FUEL AGNOSTIC COMPRESSION IGNITION ENGINE

MOTEUR A ALLUMAGE PAR COMPRESSION AGNOSTIQUE DE CARBURANT

English Abstract

Some embodiments described herein relate to a method of operating a compression ignition (CI) engine. The CI engine can include a combustion chamber. The method of operating the CI engine includes receiving a volume of intake charge in the combustion chamber, compressing the intake charge, injecting a volume of fuel into the combustion chamber, the fuel having a cetane number less than about 40, and combusting substantially all of the volume of fuel. A delay between injecting the volume of fuel into the combustion chamber and initiation of combustion is less than about 2 ms. The CI engine includes at least a two-stroke engine, an opposed-piston engine, a two-stroke opposed piston engine, a five-stroke engine, a six-stroke engine, a free-piston engine, a free piston engine linear, a rotary engine, and/or a Wankel rotary engine.

French Abstract

Certains modes de réalisation de la présente invention concernent un procédé pour faire fonctionner un moteur à allumage par compression (CI). Le moteur CI peut comprendre une chambre de combustion. Le procédé pour faire fonctionner le moteur CI comprend la réception d'un volume de charge d'admission dans la chambre de combustion, la compression de la charge d'admission, l'injection d'un volume de carburant dans la chambre de combustion, le carburant ayant un indice de cétane inférieur à environ 40, et la combustion de sensiblement la totalité du volume de carburant. Un délai entre l'injection du volume de carburant dans la chambre de combustion et l'amorçage de la combustion est inférieur à environ 2 ms. Le moteur CI comprend au moins un moteur à deux temps, un moteur à pistons opposés, un moteur à pistons opposés à deux temps, un moteur à cinq temps, un moteur à six temps, un moteur à pistons libres, un moteur à pistons libres linéaire, un moteur rotatif et/ou un moteur rotatif Wankel.

Claims

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Claims
1. A method of operating a compression ignition engine, the compression
ignition
engine including a combustion chamber, the method comprising the steps of:
receiving a volume of intake charge in the combustion chamber;
compressing the intake charge;
injecting a volume of fuel into the combustion chamber, the fuel having a
cetane
number less than about 40; and
combusting substantially all of the volume of fuel,
wherein a delay between injecting the volume of fuel into the combustion
chamber
and initiation of combustion is less than about 2 ms,
and wherein the compression ignition engine includes at least one of a two-
stroke
engine, an opposed-piston engine, a two-stroke opposed piston engine, a five-
stroke engine, a
six-stroke engine, a free-piston engine, a free piston engine linear, a rotary
engine, or a
Wankel rotary engine.
2. The method of claim 1 wherein the intake charge is manipulated to aid in
producing a
temperature in the combustion chamber sufficient to limit the delay between
injecting the
volume of fuel into the combustion chamber and initiation of combustion to be
less than
about 2 ms.
3. The method of claim 1, wherein no more than about 50% of the volume of
the fuel is
pre-mixed with the volume of intake charge upon initiation of combustion.
4. The method of claim 3, wherein no more than about 20% of the volume of
fuel is pre-
mixed with the volume of intake charge upon initiation of combustion.
5. The method of any of the preceding claims, wherein at least 40% of the
energy
generated from combusting the volume of fuel is generated while the volume of
fuel is being
injected into the combustion chamber.
6. The method of any of the preceding claims, wherein the effective
compression ratio is
between about 15:1 and about 25:1.
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7. The method of any of the preceding claims, wherein the effective
compression ratio is
greater than about 15:1.
8. The method of any of the preceding claims, wherein the fuel is a first
fuel, the volume
of intake charge is a first volume of intake charge, and the timing of fuel
injection is a first
timing with respect to the events of the engine cycle, the method further
comprising:
receiving a volume of intake charge in the combustion chamber;
compressing the intake charge;
injecting a volume of a second fuel into the combustion chamber at a second
timing
with respect to the events of the engine cycle, during a second time period,
the second fuel
having a different cetane number, heating value, and/or chemical composition
from the first
fuel;
combusting substantially all of the volume of the second fuel,
wherein the second engine crank angle is sufficiently late in the compression
process
such that no more than about 50% of the volume of the second fuel is pre-mixed
with the
second volume of intake charge upon initiation of combustion.
9. The method of claim 8, wherein the second fuel has a cetane number lower
than the
cetane number of the first fuel.
10. The method of any of the preceding claims, wherein the volume of fuel
and the
volume of intake charge are introduced into the combustion chamber in a non-
stoichiometric
fuel-air ratio.
11. The method of any of the preceding claims, further comprising: applying
a
temperature control strategy to the volume of intake charge at any point prior
to fuel
inj ecti on.
12. The method of any of the preceding claims, further comprising:
applying a temperature control strategy to the volume of intake charge prior
to it
entering the combustion chamber.
13. The method of claim 1 1 or 12, wherein the temperature control strategy
includes
exposing the volume of intake charge to an electric heater.
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14. The method of any of the preceding claims, wherein the volume of intake
charge has a
temperature of at least about 80 C prior to entering the combustion chamber.
15. The method of claim 11 or 12, wherein the temperature control strategy
includes
exposing the volume of intake charge to a burner with flame stabilization
and/or a catalytic
burner.
16 The method of any of the preceding claims, wherein the
compression ignition engine
includes a forced induction device to pressurize air from atmospheric pressure
to a pressure
higher than atmospheric pressure, including but not limited to a turbocharger
and/or
supercharger, compressor, and/or blower, the method further comprising:
substantially
eliminating aftercooling on the forced induction device.
17. The method of any of claims 11-16, wherein the temperature control
strategy includes
transferring heat from an exhaust gas to the volume of intake charge.
18. The method of any of the preceding claims, wherein the temperature
control strategy
includes at least partial retention, rebreathing and/or recirculation of the
exhaust gas.
19. The method of claim 18, wherein the exhaust gas is trapped, rebreathed,
or
manipulated to aid in producing a temperature in the combustion chamber
sufficient to limit
the delay between injecting the volume of fuel into the combustion chamber and
initiation of
combustion to be less than about 2 ms.
20. The method of claim 18 or 19, wherein the exhaust gas is at least
partially mixed with
a volume of air in the intake charge prior to receiving the intake charge in
the combustion
chamber.
21. The method of any of the preceding claims, wherein the volume of fuel
produces,
upon continued injection, a mixing-limited plume, reacting the volume of fuel
and the
volume of intake charge.
72. The method of any of the preceding claims, wherein the first
fuel has a cetane number
of less than about 10.
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23. The method of any of the preceding claims, wherein the average
temperature of the
volume of intake charge in engine cylinder just prior to fuel injection is in
a range between
about 1000 K and about 1250 K.
24. The method of any of the preceding claims, wherein the volume of fuel
includes less
than about 3 wt% of additives that result in a substantial change in cetane
number.
25. The method of claim 24, wherein the volume of fuel includes less than
about 1 wt%
of additives that result in a substantial change in cetane number.
26. The method of claim 25, wherein the volume of fuel includes less than
1,000 ppm of
additives that result in a substantial change in cetane number.
27. The method of any of the preceding claims, wherein the volume of intake
charge
includes atmospheric air, humid air, air enriched with oxygen, air diluted
with exhaust gas,
and/or air diluted with inert gas.
28. The method of any of the preceding claims, wherein the fuel includes
the following or
blends of the following: naphtha, gasoline, alcohol, butanol, propanol,
ethanol, methanol,
gaseous hydrocarbons, natural gas, methane, ethane, propane, butane, hexane,
alternative
fuels, hydrogen, ammonia, syngas, and/or CO.
29. The method of any of the preceding claims, wherein the volume of fuel
is injected
into the combustion chamber at a pressure of at least about 800 bar absolute.
30. The method of any of the preceding claims, wherein the compression
ignition engine
includes a sensor configured to detect properties of the fuel and control the
temperature
control strategy or other aspects of engine operation, based on the properties
of the fuel.
31. The method of any of the preceding claims, wherein the compression
ignition engine
includes insulation to aid in producing a temperature in the combustion
chamber sufficient to
limit the delay between injecting the volume of fuel into the combustion
chamber and
initiation of combustion to be less than about 2 ms.
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32. A method of operating a compression ignition engine, the
compression ignition
engine including a combustion chamber, the method comprising the steps of:
receiving a volume of intake chat ge in the combustion chambet,
compressing the volume of intake charge to arrive at an effective compression
ratio of
at least about 15:1;
injecting a volume of fuel into the combustion chamber, the fuel having a
cetane
number less than about 40; and
combusting substantially all of the volume of fuel,
wherein the injection timing is sufficiently late in the compression process
such that at
least 30% of the energy generated from combusting the volume of fuel is
generated while the
volume of fuel is being injected into the combustion chamber,
and wherein the compression ignition engine includes at least one of a two-
stroke
engine, an opposed-piston engine, a two-stroke opposed piston engine, a five-
stroke engine, a
six-stroke engine, a free-piston engine, a free piston engine linear, a rotary
engine, or a
Wankel rotary engine.
33 The method of claim 32, wherein the combustion chamber
includes points with local
equivalence ratios of at least about 2.
34. Thc mcthod of either of claims 32 or 33, wherein thc temperature and
pressure within
the combustion chamber at the time of fuel injection create conditions such
that no more than
about 2 ms elapse between the start of fuel injection and ignition of the
volume of fuel.
35. The method of either of claims 32 or 33, wherein the injection timing
is sufficiently
late in the compression process such that no more than about 50% of the volume
of the fuel is
pre-mixed with the volume of intake charge upon initiation of combustion.
36. The method of either of claims 32-35, wherein the temperature and
pressure within
the combustion chamber at the time of fuel injection create conditions such
that no more than
about 50% of the volume of the fuel is pre-mixed with the volume of intake
charge upon
initiation of combustion.
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37. The method of any of claims 32-35, wherein the fuel is a first fuel,
the volume of
intake charge is a first volume of intake charge, and the injection timing is
a first timing with
respect to the othei events in the engine cycle, the method further
comprising.
receiving a second volume of intake charge into the combustion chamber;
compressing the second volume of intake charge;
injecting a volume of a second fuel into the combustion chamber at a second
injection
timing with respect to the other events in the engine cycle, the second fuel
having a different
cetane number, heating value, and/or chemical composition from the first fuel;
combusting substantially all of the volume of the second fuel,
wherein the second injection timing is sufficiently late in the compression
process
such that no more than about 50% of the volume of the second fuel is pre-mixed
with the
second volume of intake charge upon initiation of combustion.
38. The method of claim 37, wherein the second fuel has a cetane number
lower than the
cetane number of the first fuel.
39. The method of any of claims 32-38, further comprising:
applying a temperature control strategy to the volume of intake charge prior
to
receiving the intake charge into the combustion chamber.
40. The method of claim 39, wherein the temperature control strategy
includes exposing
the volume of intake charge to a burner with flame stabilization and/or a
catalytic burner.
41. The method of any of claims 39-40, wherein the temperature control
strategy includes
transferring heat from an exhaust gas to the volume of intake charge.
42. The method of claim 41, wherein the temperature control strategy
includes at least
partial retention, rebreathing, and/or recirculation of the exhaust gas.
43. The method of any of claims 32-42, wherein the average temperature of
the volume of
intake charge in the combustion chamber just prior to fuel injection is in a
range between
about 1000 K and about 1250 K.
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44. The method of any of claims 32-43, wherein the volume of fuel includes
less than
about 3 wt% of additives that result in a substantial change in cetane number.
45. A method of operating a compression ignition engine, the compression
ignition
engine including a combustion chamber, the method comprising the steps of:
receiving a volume of intake charge in the combustion chamber;
compressing the volume of intake charge in the engine to arrive at an
effective
compression ratio of at least about 15:1, and a pressure and temperature
sufficient to induce
autoignition in the combustion chamber,
injecting a volume of fuel into the combustion chamber at a first timing, the
volume
of fuel having a cetane number less than about 30; and
changing the injection timing of the volume of fuel to control the rate of
pressure rise
from the combustion of the volume of fuel in the volume of intake charge to be
less than
about 15 MPa/ms,
wherein the compression ignition engine includes at least one of a two-stroke
engine,
an opposed-piston engine, a two-stroke opposed piston engine, a five-stroke
engine, a six-
stroke engine, a free-piston engine, a free piston engine linear, a rotary
engine, or a Wankel
rotary engine.
46. The method of claim 45, wherein controlling the rate of pressure rise
from the
combustion chamber is exclusively via changing the injection timing of the
volume of fuel.
47. The method of either of claims 45 or 46, wherein the injection timing
sufficiently late
in the compression process such that no more than about 50% of the volume of
the fuel is
pre-mixed with the volume of intake charge upon initiation of combustion
48. The method of either of claims 45-47, wherein the temperature and
pressure within
the combustion chamber at the time of fuel injection create conditions such
that no more than
about 50% of the volume of the fuel is pre-mixed with the volume of intake
charge upon
initiation of combustion.
49. The method of any of claims 45-48, wherein the fuel is a first fuel,
the volume of
intake charge is a first volume of intake charge, and the injection timing is
a first injection
timing, the method further comprising:
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receiving a second volume of intake charge into the combustion chamber;
compressing the volume of intake charge;
injecting a volume of a second fuel into the combustion chamber at a second
injection
timing during a second time period, the second fuel having a different cetane
number, heating
value, and/or chemical composition from the first fuel;
combusting substantially all of the volume of the second fuel,
wherein the second injection timing is sufficiently late in the compression
process
such that no more than about 50% of the volume of the second fuel is pre-mixed
with the
second volume of intake charge upon initiation of combustion
50 The method of claim 49, wherein the second fuel has a cetane
number lower than the
cetane number of the first fuel.
51. The method of any of claims 45-50, further comprising:
applying a temperature control strategy to the volume of intake charge prior
to
receiving it into the combustion chamber.
52. A method of operating a compression ignition engine, the compression
ignition
engine including a combustion chamber, the method comprising the steps of:
receiving a first volume of intake charge in the combustion chamber;
compressing the volume of intake charge in order to arrive at an effective
compression ratio of the volume of intake charge of at least about 15;
injecting a volume of a first fuel into the combustion chamber at a first
injection
timing during a first time period into the volume of intake charge having a
first temperature,
the first temperature measured at 1 ms prior to injecting the volume of the
first fuel into the
combustion chamber, the first fuel having a first cetane number less than
about 40;
combusting substantially all of the volume of the first fuel;
receiving a second volume of intake charge in the combustion chamber;
compressing
the second volume of intake charge and arrive at an effective compression
ratio of at least
about 15,
injecting a volume of a second fuel into the combustion chamber during a
second time
period into the second volume of intake charge, the second volume of intake
charge having a
second temperature higher than the first temperature, the second temperature
measured at 1
ms prior to injecting the volume of the second fuel into the combustion
chamber, the second
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fuel different than the first fuel and having a second cetane number lower
than the first cetane
number;
coinbusting substantially all of the volume of the second fuel, wherein
a delay between injecting the volume of the first fuel and the second fuel
into the
combustion chambcr and initiation of combustion of each fuel is less than
about 2 ms,
and wherein the compression ignition engine includes at least one of a two-
stroke
engine, an opposed-piston engine, a two-stroke opposed piston engine, a five-
stroke engine, a
six-stroke engine, a free-piston engine, a free piston engine linear, a rotary
engine, or a
Wankel rotary engine
53 The method of claim 52, wherein the compression ignition
engine includes an on-
board fuel sensor.
54. The method of claim 53, further comprising:
implementing a thermal management technique to adjust the temperature of the
combustion chamber based on fuel properties detected by the fuel sensor.
55. The method of any of claims 52-54, wherein the first fuel has a cetane
number
between about 30 and about 40, and the first temperature is at least about 900
K.
56. The method of any of claims 52-54, wherein the first fuel has a cetane
number
between about 20 and about 30, and the first temperature is at least about
1000 K.
57 The method of any of claims 52-54, wherein the first fuel has
a cetane number
between about 10 and about 20, and the first temperature is at least about
1050 K.
58. The method of any of claims 52-54, wherein the first fuel has a cetane
number
between about 0 and about 10, and the first temperature is at least about 1150
K.
59. The method of any of claims 52-54, wherein the first fuel has a cetane
number less
than about 0, and the first temperature is at least about 1250 K.
53
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Description

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FUEL AGNOSTIC COMPRESSION IGNITION ENGINE
Cross-reference to Related Applications
[0001]
This application claims priority and benefit of U.S. Provisional
Application No.
63/236,965, filed August 25, 2021 and titled "Fuel Agnostic Compression
Ignition Engine,"
the disclosure of which is hereby incorporated by reference in its entirety.
Technical Field
[0002]
Embodiments described herein relate to fuel agnostic compression ignition
engines,
and methods of operating the same.
Background
[0003]
A diesel engine is a rugged, reliable engine architecture having high
torque/efficiency and simple ignition control enabled by the largely non-
premixed nature of
the combustion process Standard diesel engine operation depends on the fuel
being sufficiently
ignitable in air, which requires pre-injection temperatures at least ¨850K.
These temperatures
are most commonly achieved by compressing the air in a geometric volume ratio
of about 17:1.
During operation, this air compression is accomplished in the cylinder prior
to fuel being
sprayed in from a high-pressure direct injection from the fuel injector (i.e.,
the pressure in the
fuel injector is greater than 800 bar at the point in time the fuel is
injected). Diesel fuel itself
meets this ignition criterion (i.e., igniting in air at 850K with a
sufficiently short ignition delay),
while numerous other fuels do not. This ignition criterion causes the
exclusion of fuels with
otherwise desirable attributes such as cost, regional availability, or other
properties related to
the way they burn. Currently, only fuels that can meet the diesel ignition
criteria can be used
in a diesel cycle (that is, non-premixed, mixing-controlled compression
ignition). The ignition
criteria is defined by a measurement of the fuel's ignition delay (a short
ignition delay ¨ short
compared to the other time scales in the engine cycle such as piston motion
and intake or
exhaust event durations ¨ is desired for a non-premixed combustion process),
and is reported
as a value called cetane number. A standard diesel engine has a narrow range
of cetane
numbers, for which the fuel can be combusted properly in the diesel engine.
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Summary
[0004]
Embodiments described herein relate to engines that can operate in a diesel
cycle
on any fuel regardless of cetane number, and methods of operating the same.
Some
embodiments described herein relate to a method of operating a compression
ignition (CI)
engine. The CI engine can include a combustion chamber. The method of
operating the CI
engine includes receiving a volume of intake charge in the combustion chamber,
compressing
the intake charge, injecting a volume of fuel into the combustion chamber, the
fuel having a
cetane number less than about 40, and combusting substantially all of the
volume of fuel. A
delay between injecting the volume of fuel into the combustion chamber and
initiation of
combustion is less than about 2 ms. The CI engine includes at least a two-
stroke engine, an
opposed-piston engine, a two-stroke opposed piston engine, a five-stroke
engine, a six-stroke
engine, a free-piston engine, a free piston engine linear, a rotary engine,
and/or a Wankel rotary
engine.
Brief Description of the Drawings
[0005]
FIG. 1 is a chart of autoignition delay times of various fuels as a
function of ignition
temperature
[0006]
FIG. 2 is a schematic illustration of a compression ignition architecture,
according
to an embodiment.
[0007]
FIG. 3 is a block diagram of a method of operating a compression ignition
engine,
according to an embodiment.
Detailed Description
[0008]
Chemical fuels (petroleum, alcohols, biodiesel, etc.) remain important to
heavy-
duty on-road transportation. Their high energy density is important for users
who need to travel
long distances and refuel quickly. As a result, the need for chemically fueled
diesel engines
will persist for decades. However, diesel fuel prices have increased
substantially over the last
three decades and diesel fuel is a significant contributor to greenhouse gas
emissions.
Additionally, emissions standards for nitrogen dioxide and nitric oxide
(collectively referred
to as NON) as well as soot are becoming ever stricter.
[0009]
Embodiments described herein relate to engines that can operate in a diesel
cycle
on any fuel regardless of cetane number, and methods of operating the same. In
some
embodiments, an engine can operate as a "fuel agnostic" engine by creating a
high temperature
environment inside the engine or in the immediate vicinity of the engine In
some
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embodiments, the high temperature environment can be created without having to
change the
traditional diesel engine architecture. In other words, the compression ratio
of the diesel engine
can remain the same, with only minimal changes to other components or aspects
of the diesel
engine. An increase in temperature can shorten the ignition delay of a fuel,
allowing the fuel
to behave in a similar manner to how a more ignitable fuel would behave at a
lower
temperature. For example, a first fuel with a cetane number of 55 can have a
similar ignition
delay at 700 K to the ignition delay of a second fuel with a cetane number of
15 at 1000 K. At
sufficiently high temperatures, all fuels (even those most resistant to
ignition) have sufficiently
short ignition del ay to sustain diesel style engine operation. Fuels have
ignition del ay curves
that can depend on temperature, pressure, oxygen content of the air mixture in
a cylinder the
fuel is injected into, and/or any other factors.
[0010]
In some embodiments, the high-temperatures created to achieve a "fuel
agnostic"
characteristic can be implemented in engine architectures other than a four-
stroke diesel engine
architecture, including but not limited to two-stroke engines, opposed-piston
engines, two-
stroke opposed piston engines, five-stroke engines, six-stroke engines, free-
piston engines, free
piston engines linear, rotary or Wankel rotary engine designs, or other
internal combustion
engine designs.
[0011]
FIG. 1 shows a chart of autoignition delay times of various fuels as a
function of
ignition temperature. The x-axis shows initial temperature upon ignition,
while the y-axis
shows autoignition delay times as a function of initial temperature. Fuels
shown on this chart
include methane, iso-octane, n-heptane, and dimethyl ether (DME). Of the fuels
shown, DME
has the highest cetane number, about 55. Therefore, the other fuels shown (n-
heptane, iso-
octane, methane) require a higher temperature than DME to ignite after a given
delay period
(e.g., 2 ms). Ignition delay can be reduced or finely tuned by manipulating
the temperature in
the combustion chamber.
[0012]
Benefits to creating a high temperature in the combustion chamber can
include
enablement of a fuel-flexible engine that can match the torque and power
density of a diesel
engine with the freedom to operate on any fuel, regardless of cetane number.
In some
embodiments, the fuel agnostic or fuel-flexible engine can be configured such
that one or more
on-board sensors detect fuel properties and control a temperature control
mechanism employed
in the engine. For example, the temperature control mechanism can add more
heat to
compensate when the sensor detects a low-cetane fuel. In some embodiments, the
engine can
be configured to adjust the amount of fuel injected, injection
timing/scheduling, injection
pressure, amount of exhaust gas retention (EGR), or any other suitable factors
to achieve a
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desired engine load and combustion phasing, based on the fuel detected by the
on-board sensor.
This type of versatility can allow an owner or operator of the engine to
choose a fuel that is
most available, most affordable, or a fuel that meets any other desired
criterion on any given
occasion. The fuel-agnostic combustion process can de-couple the desirable
attributes of the
diesel cycle from fuel having ignition characteristics similar to those of
diesel fuel. Fuels can
instead be chosen based on other factors, such as cost, availability, carbon
intensity, or
emissions criteria.
[0013]
FIG. 2 shows a compression ignition (CI) engine 200 that includes a
cylinder 210,
a piston 220 configured to move in the cylinder 210, a head deck 225, an
intake valve 230, and
an exhaust valve 240. The cylinder 210, piston 220, head deck 225, intake
valve 230, and
exhaust valve 240 collectively define the combustion chamber 250. The intake
valve 230 can
cover an intake port (not shown) and the intake valve 230 can be opened to
uncover the intake
port (i.e., to allow fluid flow through the intake port). The exhaust valve
240 can cover an
exhaust port and the exhaust valve 240 can be opened to uncover the exhaust
port (i.e., to allow
fluid flow through the exhaust port). In some embodiments, the CI engine 200
can be absent
of the intake valve 230 and the exhaust valve 240 and simply include the
intake ports and the
exhaust ports. As a non-limiting example of such an embodiment, a two-stroke
engine can be
absent of intake valves and/or exhaust valves.
[0014]
In some embodiments, the CI engine 200 can be absent a cylinder head, such
as in
the case of an opposed piston engine. In such cases, the boundaries of the
combustion chamber
250 can be defined by other surfaces, such as multiple pistons, a cylinder
wall, and/or other
boundaries creating the combustion chamber.
[0015]
In some embodiments, the CI engine 200 can have a non-cylindrical
combustion
chamber, as in the case of a Wankel-style rotary engine or other rotary engine
designs. In this
case, rather than a "cylinder" the engine has a combustion chamber defined by
pi ston(s) and a
combustion chamber wall.
[0016]
As shown, the CI engine 200 further includes a first fuel supply 260a, a
second fuel
supply 260b (collectively referred to as fuel supplies 260), an exhaust
aftertreatment device
265, a fuel injector 270, a sensor 272, a crankshaft 280, a recirculation path
290, and an EGR
cooler 295. The intake valve 240 and the exhaust valve 250 can both be in
contact with
camshafts (not shown) that rotate to open and close the intake valve 240 and
the exhaust valve
250 in accordance with the timing and distance necessary to achieve the
desired intake. In
some embodiments, the intake valve 240 and the exhaust valve 250 can operate
with a variable
valve timing (VVT) scheme, as described in International Patent Publication WO
2020/232287
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("the '287 publication"), filed May 14, 2020 and entitled "Cold Start for High-
Octane Fuels in
a Diesel Engine Architecture," the disclosure of which is hereby incorporated
by reference in
its entirety. In some embodiments, one or more components of the CI engine 200
can include
a thermal barrier coating 255, as described in U.S. Patent No. 9,903,262
entitled,
"Stoichiometric High-Temperature Direct-Inj ection Compression-Ignition
Engine," filed April
6, 2015 ("the '262 patent"), the disclosure of which is incorporated herein by
reference in its
entirety. Examples of fuel agnostic implementations are described in
International Patent
Application No. PCT/US2021/019930 entitled, "Fuel Agnostic Compression
Ignition Engine,"
filed February 26, 2021 ("the '930 patent"), the disclosure of which is
incorporated herein by
reference in its entirety.
[0017]
In some embodiments, the cylinder 210 can have a bore of at least about 1
cm, at
least about 2 cm, at least about 3 cm, at least about 4 cm, at least about 5
cm, at least about 6
cm, at least about 7 cm, at least about 8 cm, at least about 9 cm, at least
about 10 cm, at least
about 20 cm, at least about 30 cm, at least about 40 cm, at least about 50 cm,
at least about 60
cm, at least about 70 cm, at least about 80 cm, at least about 90 cm, or at
least about 100 cm (1
m). In some embodiments, the cylinder 210 can have a bore of no more than
about 100 cm (1
m), no more than about 90 cm, no more than about 80 cm, no more than about 70
cm, no more
than about 60 cm, no more than about 50 cm, no more than about 40 cm, no more
than about
30 cm, no more than about 20 cm, no more than about 10 cm, no more than about
9 cm, no
more than about 8 cm, no more than about 7 cm, no more than about 6 cm, no
more than about
cm, no more than about 4 cm, no more than about 3 cm, or no more than about 2
cm.
[0018]
Combinations of the above-referenced bore values of the cylinder 210 are
also
possible (e.g., at least about 1 cm and no more than about 100 cm, or at least
about 5 cm and
no more than about 20 cm), inclusive of all values and ranges therebetween. In
some
embodiments, the cylinder 210 can have a bore of about 1 cm, about 2 cm, about
3 cm, about
4 cm, about 5 cm, about 6 cm, about 7 cm, about 8 cm, about 9 cm, about 10 cm,
about 20 cm,
about 30 cm, about 40 cm, about 50 cm, about 60 cm, about 70 cm, about 80 cm,
about 90 cm,
about 100 cm, or larger than about 100 cm.
[0019]
As shown, the first fuel supply 260a is fluidically coupled to the fuel
injector 270.
The fuel injector 270 injects fuel into the combustion chamber 250. As shown,
the second fuel
supply 260b is also fluidically coupled to the fuel injector 270. As shown,
the first fuel supply
260a and the second fuel supply 260b are both fluidically coupled to the same
fuel injector 270.
In some embodiments, the first fuel supply 260a can be fluidically coupled to
a first fuel
injector and the second fuel supply 260b can be fluidically coupled to a
second fuel injector.
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In some embodiments, the first fuel supply 260a can contain a first fuel and
the second fuel
supply 260b can contain a second fuel. In some embodiments, the second fuel
can have a
different cetane number, heating value, and/or chemical composition from the
first fuel. As
shown, the CI engine includes two fuel supplies 260a, 260b. In some
embodiments, the CI
engine can include 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
19, 20, or at least 20 fuel
supplies 260, inclusive of all values and ranges therebetween. In some
embodiments, the
exhaust aftertreatment device 265 can include a three-way catalyst.
[0020]
As shown, the fuel injector 270 injects fuel parallel to the motion of the
piston 220.
In some embodiments, the fuel injector 270 can inject fuel at an angle of
about 5 , about 10 ,
about 15 , about 20 , about 25 , about 30 , about 35 , about 40 , about 45 ,
about 50', about
55 , about 60 , about 65 , about 70 , about 75 , about 80 , about 85 , or
about 90 relative to
the motion of the piston 220, inclusive of all values and ranges therebetween.
[0021]
In some embodiments, the piston 220 can include a low heat transfer piston.
In
some embodiments, the piston 220 can include a full metal piston with an
insulating material.
In some embodiments, the CI engine 200 can be absent of a piston, and the
compression of the
contents inside the combustion chamber 250 can be achieved via other means
(e.g., in a Wankel
rotary engine, where the compression of the contents in the combustion chamber
occur via
rotation of the rotor around an eccentric shaft).
[0022]
In some embodiments, the sensor 272 can detect or aid in detecting the type
of fuel
being injected into the combustion chamber 250. In some embodiments, the
sensor 272 can
detect or aid in detecting a certain property of the fuel once the fuel is
combusted. In some
embodiments, the sensor 272 can detect relative permittivity of the fuel being
injected into the
combustion chamber 250 or use the capacitive principle. In some embodiments,
the sensor 272
can detect pH. In some embodiments, the sensor 272 can include a heating
element such that
the sensor 272 can detect a boiling point or a vaporization point of the fuel
entering the
combustion chamber 250. In some embodiments, the sensor 272 can include a
pressure
transducer. In some embodiments, the sensor 272 can include a temperature
sensor or a
temperature sensing device. In some embodiments, the sensor 272 can include
tooling for
infrared spectroscopy. In some embodiments, the sensor 272 can include a gel
that changes
color when it absorbs a certain type of fuel (e.g., carbon monoxide). In some
embodiments, a
light sensor can detect a change in color in the gel and can accordingly
detect the type of fuel
being injected. In some embodiments, if the sensor 272 is in the exhaust port,
manifold, path,
or near the aftertreatment device, then the detected oxygen content,
temperature, and/or other
quantities of the fuel or fuel's combustion products can be used to infer fuel
attributes and
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inform a control mechanism to adjust the temperature control mechanism and
fueling
accordingly.
[0023]
In some embodiments, the sensor 272 can communicate with various components
of the CI engine 200. In some embodiments, the sensor 272 can communicate with
the
recirculation path 290. For example, the sensor 272 can alert the
recirculation path 290 to
recirculate more exhaust to raise the temperature in the combustion chamber
250 when the
sensor 272 detects a low cetane fuel. In some embodiments, the sensor 272 can
communicate
with the EGR cooler 295 to reduce cooling in order to raise the temperature in
the combustion
chamber 250 In some embodiments, the sensor 272 can communicate with a
variable
geometry turbocharger and/or any other variable exhaust restriction device to
raise pressure in
the exhaust manifold in order to drive a larger quantity of exhaust through
the recirculation
path 290. In some embodiments, the sensor 272 can communicate with a grid
heater (not
shown) to change the rate heat is added to a volume of air entering the
combustion chamber
250. In some embodiments, the CI engine 200 can include an EGR crossover tube
(not shown).
In some embodiments the sensor 272 can communicate with a variable valve
timing mechanism
to trap or re-breathe more or less exhaust to change the mass-averaged
temperature of gases in
the cylinder. In some embodiments, the sensor 272 can communicate with a flame
stabilizer
(not shown) to change the rate heat is added to the volume of air entering the
combustion
chamber 250. In some embodiments, the sensor 272 can communicate with a
catalytic burner
(not shown) to change the rate heat is added to the volume of air entering the
combustion
chamber 250. In some embodiments, the sensor 272 can communicate with a forced
induction
device (not shown) to compress air to a pressure greater than atmospheric
pressure. In some
embodiments, the sensor 272 can communicate with a turbocharger and/or
supercharger (not
shown) to change the amount of aftercooling on the turbocharger and/or
supercharger. In some
embodiments, the sensor 272 can communicate with a Roots blower (not shown) to
change the
amount of compression or aftercooling on the Roots blower. In some
embodiments, the sensor
272 can substantially eliminate aftercooling on the turbocharger,
supercharger, and/or other
forced induction device. In some embodiments, the sensor 272 can communicate
with the fuel
injector 270 to modify the pressure at which fuel is injected from the fuel
injector 270. In some
embodiments, the sensor 272 can communicate with the fuel injector 270 to
modify the timing
or scheduling of fuel injection events.
[0024]
As shown, the sensor 272 is disposed in the combustion chamber 250. In some
embodiments, the sensor 272 can be coupled to the fuel line at a point between
the fuel supplies
260 and the fuel injector 270. In some embodiments, the sensor 272 can be
coupled to a fuel
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tank or the fuel supply 260. In some embodiments, the sensor can be located
inside the fuel
tank. In some embodiments, the sensor can be coupled to an exhaust stream. In
some
embodiments, the sensor can be located in the exhaust port and/or exhaust
manifold In some
embodiments, the sensor can be located in the exhaust recirculation path 290.
In some
embodiments, the sensor can be located near an aftcrtreatment device (e.g.,
the aftertreatment
device 265). In some embodiments, the sensor 272 can be physically coupled to
the fuel injector
270. In some embodiments, the sensor 272 can be physically coupled to the fuel
injector 270
inside the combustion chamber 250. In some embodiments, the sensor 272 can be
physically
coupled to the fuel injector 270 outside the combustion chamber 250 In some
embodiments,
the sensor 272 can be disposed in a bowl region of the combustion chamber 250.
In some
embodiments, the sensor 272 can be disposed in a squish region of the
combustion chamber
250. In some embodiments, the CI engine can include multiple sensors disposed
at different
locations. In some embodiments the sensor 272 can be situated in the exhaust
to detect
temperature, oxygen concentration, or other quantities.
[0025]
Based on fuel properties the sensor 272 detects, thermal management
techniques
can be implemented to facilitate combustion with minimal ignition delay. For
example, a grid
heater can apply heat or increase its rate of heat supply based on the
detection of a low-cetane
fuel by the sensor 272 in order to minimize ignition delay.
[0026]
Based on fuel properties the sensor 272 detects, other attributes of the
engine control
can be implemented to facilitate combustion with desired phasing, such as
adjusting injection
timing or scheduling, addition of a pilot injection, adjusting injection
pressure, exhaust back-
pressure, EGR valve position, and/or any other engine control attributes.
[0027]
In some embodiments, the CI engine 200 can include an intake manifold (not
shown). In some embodiments, the intake manifold can include a heater. In some

embodiments, intake manifold heating can be implemented at ambient
temperatures above 0
C. In some embodiments, the intake manifold heater operation can include idle
or "off'
operating conditions. In some embodiments, the CI engine 200 can include a
control strategy
of when to use and when not to use the intake manifold heating. In some
embodiments, the CI
engine 200 can include a dedicated EGR cylinder (not shown). In some
embodiments; the CI
engine 200 can include an external source of hot exhaust (not shown).
[0028]
In some embodiments, the CI engine 200 can include an aftercooler (not
shown).
In some embodiments, the CI engine 200 can include an adjustable aftercooler
bypass (not
shown). In some embodiments, the CI engine 200 can employ the aftercooler
bypass and
control combustion air temperature.
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[0029]
In some embodiments, the CI engine 200 can be equipped with a variable
geometry
turbocharger (VGT) or waste-gated turbocharger, allowing for adjustment of the
work
extracted and compression provided by the turbocharger, while simultaneously
adjusting back-
pressure in the exhaust manifold. In some embodiments, the CI engine 200 can
be operated
such that a VGT or other adjustable back-pressure device can be used to force
higher flow of
exhaust through the recirculation path in order to control intake conditions
(e.g., temperature,
pressure, and/or mixture composition of the intake charge).
[0030]
In some embodiments, the CI engine 200 can be equipped with an EGR pump, or
an exhaust pumping device In some embodiments, the EGR pump or exhaust pumping
device
can be used to force exhaust through the recirculation path in the absence of
a driving pressure
gradient, or to overcome an adverse pressure gradient. In some embodiments,
the EGR pump
or exhaust pumping device can be used to control intake conditions
(temperature, pressure, or
mixture composition of the intake charge). In some embodiments, the EGR pump
or exhaust
pumping device can be coupled to one or many sensors detecting intake
conditions, fuel
properties, exhaust composition or properties, or other aspects of the
engine's operation.
[0031]
FIG. 3 is a block diagram of a method 10 of operating a CI engine,
according to an
embodiment. As shown, the method 10 includes receiving a volume of intake
charge in the
combustion chamber at step 11. The method 10 optionally includes applying a
temperature
control strategy at step 12. In some embodiments the temperature control
strategy at step 12
can take place prior to receiving intake charge in the combustion chamber at
step 11. The
method 10 optionally includes closing the intake valve at step 13, and
optionally includes
moving the piston from BDC to TDC at step 14. In some embodiments the
combustion chamber
contents are compressed by some other means than moving a piston from BDC to
TDC such
as in a rotary or Wankel engine. The method 10 includes injecting fuel into
the combustion
chamber at step 15, and combusting the fuel at step 16. The method 10
optionally includes
injecting and combusting additional fuel (e.g., a second fuel) at step 17. In
some embodiments,
the CI engine and the combustion chamber can be same or substantially similar
to the CI engine
200 and the combustion chamber 250, as described above with reference to FIG.
2.
[0032]
Step 11 includes receiving a volume of intake charge in the combustion
chamber.
In some embodiments, using four-stroke engine crank angle convention, the
intake process can
begin at an engine crank angle of at least about 660 , at least about 665 , at
least about 670 ,
at least about 675 , at least about 680 , at least about 685 , at least about
690 , at least about
695 , or at least about 700 . In some embodiments, the intake process can
begin at an engine
crank angle of no more than about 705', no more than about 700', no more than
about 695',
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no more than about 690 , no more than about 685 , no more than about 6800, no
more than
about 675 , no more than about 670 , or no more than about 665 . Combinations
of the above-
referenced engine crank angles for the start of the intake process are also
possible (e.g., at least
about 660 and no more than about 7050 or at least about 665 and no more than
about 700 ),
inclusive of all values and ranges therebetween. In some embodiments, the
intake process can
begin at an engine crank angle of about 660 , of about 665 , of about 670 ,
about 675', about
680 , about 685 , about 690 , about 695 , about 700 , or about 7050

.
[0033]
In some embodiments, the volume of intake charge drawn into the combustion
chamber during step 11 can include atmospheric air, humid air, air enriched
with oxygen, air
diluted with exhaust gas, air diluted with inert gas, air mixed with an amount
of uncombusted
fuel, or any combination thereof. In some embodiments, the volume of intake
charge can be
enriched with oxygen, such that the volume of intake charge has an oxygen
content of at least
about 25%, at least about 30%, at least about 35%, at least about 40%, at
least about 45%, at
least about 50%, or at least about 55% by volume. In some embodiments, the
volume of intake
charge can have an oxygen content of no more than about 60%, no more than
about 55%, no
more than about 50%, no more than about 45%, no more than about 40%, no more
than about
35%, or no more than about 30% by volume. Combinations of the above-referenced
values of
oxygen content in the volume of intake charge are also possible (e.g., at
least about 25% and
no more than about 60% by volume or at least about 30% and no more than about
50% by
volume), inclusive of all values and ranges therebetween. In some embodiments,
the volume
of intake charge can have an oxygen content of about 25%, about 30%, about
35%, about 40%,
about 45%, about 50%, about 55%, or about 60% by volume.
[0034]
In some embodiments, the volume of intake charge drawn into the combustion
chamber during step 11 can include fuel. In some embodiments, the volume of
intake charge
drawn into the combustion chamber during step 11 can include at least about
1%, at least about
2%, at least about 3%, at least about 4%, at least about 5%, at least about
6%, at least about
7%, at least about 8%, at least about 9%, at least about 10%, at least about
11%, at least about
12%, at least about 13%, at least about 14%, at least about 15%, at least
about 16%, at least
about 17%, at least about 18%, or at least about 19% v:v fuel. In some
embodiments, the
volume of intake charge drawn into the combustion chamber during step 11 can
include no
more than about 20%, no more than about 19%, no more than about 18%, no more
than about
17%, no more than about 16%, no more than about 15%, no more than about 14%,
no more
than about 13%, no more than about 12%, no more than about 11%, no more than
about 10%,
no more than about 9%, no more than about 8%, no more than about 7%, no more
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6%, no more than about 5%, no more than about 4%, no more than about 3%, or no
more than
about 2% v:v fuel. Combinations of the above-referenced volumetric percentages
of fuel in
the volume of intake charge are also possible (e.g., at least about 1% and no
more than about
20% or at least about 5% and no more than about 15%), inclusive of all values
and ranges
therebetween. In some embodiments, the volume of intake charge drawn into the
combustion
chamber during step 11 can include about 1%, about 2%, about 3%, about 4%,
about 5%, about
6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%,
about
14%, about 15%, about 16%, about 17%, about 18%, about 19%, or about 20% v.v
fuel.
100351
At step 12, the method 10 optionally includes applying a temperature
control
strategy. In some embodiments, the temperature in the combustion chamber can
be
manipulated by heating the volume of intake charge prior to drawing the volume
of intake
charge into the combustion chamber. Since the charge is heated during the
compression step
of the engine cycle, inlet air temperatures can be increased before, during,
or after intake, or
before, during, or after the compression step to achieve a sufficiently high
temperature in the
combustion chamber prior to the injection of fuel into the combustion chamber.
In other words,
the volume of intake charge can be heated to an intermediate value prior to or
upon entering
the combustion chamber, and then the compression in the combustion chamber can
raise the
temperature of the volume of intake charge (and the fuel) to a suitable
combustion chamber
with minimal ignition delay. As an example, the volume of intake charge can be
heated to a
temperature of about 130 C to achieve a pre-fuel injection temperature inside
the combustion
chamber of about 1100 C. In some embodiments, the volume of intake charge can
be heated
to a temperature of at least about 50 C, at least about 60 C, at least about
70 C, at least about
80 'V, at least about 90 'V, at least about 100 "V, at least about 110 C, at
least about 120 CC,
at least about 130 C, at least about 140 C, at least about 150 C, at least
about 160 C, at least
about 170 C, at least about 180 C, at least about 190 C, at least about 200
C, at least about
210 C, at least about 220 C, at least about 230 C, at least about 240 C,
at least about 250
C, at least about 260 C, at least about 270 C, at least about 280 C, or at
least about 290 C
prior to or upon entering the combustion chamber. In some embodiments, the
volume of intake
charge can be heated to a temperature of no more than about 300 CC, no more
than about 290
C, no more than about 280 C, no more than about 270 C, no more than about
260 C, no
more than about 250 C, no more than about 240 C, no more than about 230 C,
no more than
about 220 C, no more than about 210 C, no more than about 200 C, no more
than about 190
C, no more than about 180 C, no more than about 170 C, no more than about
160 C, no
more than about 150 C, no more than about 140 C, no more than about 130 CC,
no more than
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about 120 C, no more than about 110 C, no more than about 100 C, no more
than about 90
C, no more than about 80 C, no more than about 70 C, or no more than about
60 C prior to
or upon entering the combustion chamber. Combinations of the above-referenced
temperatures
of the volume of intake charge prior to or upon entering the combustion
chamber are also
possible (e.g., at least about 50 C and no more than about 300 C or at least
about 100 C and
no more than about 200 C), inclusive of all values and ranges therebetween.
In some
embodiments, the volume of intake charge can be heated to a temperature of
about 50 C, about
60 'V, about 70 'V, about 80 'V, about 90 'V, about 100 C, about 110 'V,
about 120 C, about
130 C, about 140 C, about 150 C, about 160 C, about 170 C, about 180 C,
about 190 C,
about 200 C, about 210 C, about 220 C, about 230 C, about 240 C, about
250 C, about
260 C, about 270 C, about 280 C, about 290 C, or about 300 C prior to or
upon entering
the combustion chamber.
[0036]
In some embodiments, step 12 can include eliminating aftercooling on a
turbocharger, supercharger, and/or other forced induction device, using
electric heating, adding
heat from the engine's exhaust, adding or recirculating the engine's exhaust,
or some other
method to increase temperature. In some embodiments, adding heat from the CI
engine's
exhaust can be via heat exchange (i.e., through the walls of a heat exchange
apparatus). In
some embodiments, adding heat from the CI engine's exhaust can include
introducing hot
exhaust gas into the volume of intake charge drawn into the combustion chamber
(i.e., EGR).
In some embodiments, the volume of intake charge drawn into the combustion
chamber upon
opening the intake valve can include at least about 1%, at least about 2%, at
least about 3%, at
least about 4%, at least about 5%, at least about 10%, at least about 15%, at
least about 20%,
at least about 25%, at least about 30%, at least about 35%, at least about
40%, at least about
45%, at least about 50%, or at least about 55% by weight of recirculated
exhaust gas. In some
embodiments, the volume of intake charge drawn into the combustion chamber
upon opening
the intake valve can include no more than about 60%, no more than about 55%,
no more than
about 50%, no more than about 45%, no more than about 40%, no more than about
35%, no
more than about 30%, no more than about 25%, no more than about 20%, no more
than about
15%, no more than about 10%, no more than about 5%, no more than about 4%, no
more than
about 3%, or no more than about 2% by weight of recirculated exhaust gas.
Combinations of
the above-referenced weight percentages of exhaust gas in the volume of intake
charge drawn
into the combustion chamber upon opening the intake valve are also possible
(e.g., at least
about 1% and no more than about 50% or at least about 10% and no more than
about 30%),
inclusive of all values and ranges therebetween. In some embodiments, the
volume of intake
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charge drawn into the combustion chamber upon opening the intake valve can
include about
1%, about 2%, about 3%, about 4%, about 5%, about 10%, about 15%, about 20%,
about 25%,
about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, or about 60%
by weight
of recirculated exhaust gas. In some embodiments, a burner with flame
stabilization and/or a
catalytic burner can be used to create hot combustion products in the intake
channel of the CI
engine to elevate the temperature of the air drawn into the combustion
chamber. In some
embodiments a designated exhaust cylinder can be used to provide hot exhaust
to the intake
charge. In some embodiments hot exhaust or hot air can come to the intake
charge from an
external source In some embodiments, a grid heater can be used to apply heat
to the volume
of intake charge prior to being drawn into the combustion chamber.
[0037]
In addition to introducing higher temperature air or intake mixture into
the CI
engine, an insulating effect within the CI engine can retain thermal energy
that can achieve the
sufficiently high pre-injection temperature to achieve combustion of any fuel
in a diesel style
architecture. In some embodiments, thermal insulation can include surface
treatments, use of
low thermal conductivity materials, elevated coolant temperatures, and/or any
other method of
reduced cooling. In some embodiments, the insulation can be located on the
piston, on the
intake valve surface, within the intake valve, on the exhaust valve surface,
within the exhaust
valve, on the cylinder head if present, and/or any other suitable locations in
the CI engine.
Further examples of thermal insulation are described in the '262 patent.
[0038]
In some embodiments, any combination of the above-referenced thermal
management methods can be used together in parallel and/or in series. In other
words, a first
thermal management method can be used for a first time period, and a second
thermal
management method can be used for a second time period. In some embodiments,
the second
thermal management method can be different from the first thermal management
method. In
some embodiments, the first time period can at least partially overlap with
the second time
period. In some embodiments, the first time period can fully overlap with the
second time
period. In some embodiments, the first time period can be separate from the
second time
period. In some embodiments, the first thermal management method can have a
shorter
response time than the second thermal management method. For example, in a
transient
situation, a heater (e.g., a grid heater or glow plug) can be used during the
first time period and
EGR can be used during the second time period. A heater has a shorter response
time, and can
be effective more quickly (i.e., in less than one second), while EGR can be
slower to respond
and be effective.
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[0039]
In some embodiments, the method 10 can include implementing an EGR
recirculation strategy external to the combustion chamber. In some
embodiments, the method
can be implemented without EGR cooling up to a prescribed power level. In some

embodiments, intake charge temperature can be controlled by limiting or fully
eliminating EGR
cooling. In other words, the method 10 can be implemented without the use of a
prechamber
or a glow plug.
[0040]
In some embodiments, the first time period and/or the second time period
can be
about 20 ms, about 40 ms, about 60 ms, about 80 ms, 0.1 seconds, about 0.2
seconds, about 0.3
seconds, about 0.4 seconds, about 0.5 seconds, about 0.6 seconds, about 0.7
seconds, about 0.8
seconds, about 0.9 seconds, about 1 second, about 1.1 seconds, about 1.2
seconds, about 1.3
seconds, about 1.4 seconds, about 1.5 seconds, about 1.6 seconds, about 1.7
seconds, about 1.8
seconds, about 1.9 seconds, about 2 seconds, about 4 seconds, about 6 seconds,
about 8
seconds, about 10 seconds, about 12 seconds, about 14 seconds, about 16
seconds, about 18
seconds, about 20 seconds, about 25 seconds, about 30 seconds, about 35
seconds, about 40
seconds, about 45 seconds, about 50 seconds, about 55 seconds, about 60
seconds, about 70
seconds, about 80 seconds, about 90 seconds, about 100 seconds, about 110
seconds, or about
120 seconds, inclusive of all values and ranges therebetween.
[0041]
The method 10 can further include closing the intake valve at step 13.
Closing the
intake valve can be pertinent to engine designs that include an intake valve
(e.g., some four-
stroke engine designs), but can be irrelevant to engine designs without an
intake valve (e.g.
some two-stroke engine designs). In some embodiments, the intake valve can be
closed at an
engine crank angle (using four-stroke engine crank angle convention) of at
least about 160 , at
least about 165', at least about 170', at least about 175', at least about
180', at least about 185',
at least about 190 , at least about 195 , at least about 200 , at least about
205 , at least about
210 , at least about 215 , at least about 220 , at least about 225 , at least
about 230 , at least
about 235 , at least about 240 , at least about 245 , at least about 250 , or
at least about 255 .
In some embodiments, the intake valve can be closed at an engine crank angle
of no more than
about 260 , no more than about 255 , no more than about 250 , no more than
about 245 , no
more than about 240', no more than about 235', no more than about 230', no
more than about
225 , no more than about 220 , no more than about 215 , no more than about 210
, no more
than about 205 , no more than about 200 , no more than about 195 no more than
about 190 ,
no more than about 185 , no more than about 180 , no more than about 175 , no
more than
about 170 , or no more than about 165 . Combinations of the above-referenced
engine crank
angles for the closing of the intake valve are also possible (e.g., at least
about 160' and no more
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than about 260 or at least about 1800 and no more than about 200 ), inclusive
of all values
and ranges therebetween. In some embodiments, intake valve can be closed at an
engine crank
angle of about 160', about 165', about 170 , about 175 , about 180", about
185", about 190 ,
about 195 , about 200 , about 205 , about 210 , about 215 , about 220 , about
225', about
230 , about 235 , about 240 , about 245 , about 250 , about 255 , or about 260
.
[0042]
The method 10 can further include closing the intake valve, or concluding
the intake
process, at step 13. Closing the intake valve can be pertinent to engine
designs that include an
intake valve (e.g., some four-stroke engine designs), but can be irrelevant to
engine designs
without an intake valve (e g some two-stroke engine designs) In some
embodiments, the
intake process can be concluded at a time, relative to the end of the
compression process, of at
least about 1 ms prior to the end of the compression process, at least about 2
ms prior to the
end of the compression process, at least about 5 ms prior to the end of the
compression process,
at least about 10 ms prior to the end of the compression process, at least
about 25 ms prior to
the end of the compression process, at least about 50 ms prior to the end of
the compression
process, at least about 100 ms prior to the end of the compression process, at
least about 250
ms prior to the end of the compression process, at least about 500 ms prior to
the end of the
compression process, or at least about 1 second prior to the end of the
compression process. In
some embodiments, the intake process can be concluded at a time of no more
than about 1
second prior to the end of the compression process, no more than about 500 ms
prior to the end
of the compression process, no more than about 250 ms prior to the end of the
compression
process, no more than about 100 ms prior to the end of the compression
process, no more than
about 50 ms prior to the end of the compression process, no more than about 25
ms prior to the
end of the compression process, no more than about 10 ms prior to the end of
the compression
process, no more than about 5 ms prior to the end of the compression process,
no more than
about 2 ms prior to the end of the compression process, or no more than about
1 ms prior to the
end of the compression process.. Combinations of the above-referenced timing
for the closing
of the intake valve or end of induction process with respect to the end of the
compression
process are also possible (e.g., at least about 2 ms and no more than about 1
second, or at least
about 10 ms and no more than about 50 ms prior to the end of the compression
process),
inclusive of all values and ranges therebetween. In some embodiments, intake
valve can be
closed or the intake process ended at a time with respect to the end of the
compression process
of about 1 ms prior, about 2 ms prior, about 5 ms prior, about 10 ms prior,
about 25 ms prior,
about 50 ms prior, about 100 ms prior, about 250 ms prior, about 500 ms prior,
about 750 ms
prior, or about 1 second prior to the end of the compression process.
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[0043]
In some embodiments, thermal energy can be added to the CI engine during
the
compression stroke from sources other than the compression process. In some
embodiments,
the combustion chamber can include heating devices such as a glow plug, a hot
air jet, plasma,
and/or any other device for introduction of additional thermal energy to the
volume of intake
charge and/or the volume of fuel in the combustion chamber prior to ignition.
In some
embodiments, the temperature of the volume of intake charge and/or the volume
of fuel in the
combustion chamber prior to ignition can be tuned to the ignition
characteristics of each fuel
being used in the engine. In some embodiments, the rise in temperature of the
volume of intake
charge and/or the volume of fuel in the combustion chamber can be held
constant at a value
high enough that any fuel to be used in the engine would ignite with minimal
ignition delay
(e.g., an ignition delay of less than 2 ms).
[0044]
The method 10 optionally includes moving the piston from BDC to TDC at step
14
to compress the charge. Step 14 of the method 10 can include other ways of
compressing the
charge to a pressure higher than the pressure upon intake. In many engines
compressing the
charge can be accomplished using piston movement. In engines such as rotary or
Wankel
engines compressing the charge can be accomplished through other movement of
components
defining the combustion chamber boundary to accomplish the compression. In
some
embodiments, the CI engine can have a compression ratio of at least about
10.1, at least about
11:1, at least about 12:1, at least about 13:1, at least about 14:1, at least
about 15:1, at least
about 16:1, at least about 17:1, at least about 18:1, at least about 19:1, at
least about 20:1, at
least about 21:1, at least about 22:1, at least about 23:1, at least about
24:1, at least about 25:1,
at least about 26:1, at least about 27:1, at least about 28:1, or at least
about 29:1. In some
embodiments, the CI engine can have a compression ratio of no more than about
30:1, no more
than about 29:1, no more than about 28:1, no more than about 27:1, no more
than about 26:1,
no more than about 25:1, no more than about 24:1, no more than about 23:1, no
more than
about 22:1, no more than about 21:1, no more than about 20:1, no more than
about 19:1, no
more than about 18:1, no more than about 17:1, no more than about 16:1, no
more than about
15:1, no more than about 14:1, no more than about 13:1, no more than about
12:1, or no more
than about 11:1. Combinations of the above-referenced compression ratios are
also possible
(e.g., at least about 10:1 and no more than about 30:1 or at least about 13:1
and no more than
about 20:1), inclusive of all values and ranges therebetween. In some
embodiments, the CI
engine can have a compression ratio of about 10:1, about 11:1, about 12:1,
about 13:1, about
14:1, about 15:1, about 16:1, about 17:1, about 18:1, about 19:1, about 20:1,
about 21:1, about
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22:1, about 23:1, about 24:1, about 25:1, about 26:1, about 27:1, about 28:1,
about 29:1, or
about 30:1.
[0045]
In some embodiments, moving the piston(s) or other features of the
combustion
chamber to accomplish compression can occur at least partially concurrently
with the induction
of intake charge into the combustion chamber. In some embodiments, moving the
piston(s) or
other features of the combustion chamber to accomplish compression can occur
substantially
concurrently with the induction of intake charge into the combustion chamber.
In some
embodiments, moving the piston(s) or other features of the combustion chamber
to accomplish
compression can occur with little or no overlap to the induction of intake
charge into the
combustion chamber. In some embodiments, moving the piston from BDC to TDC (in
the case
of two-stroke, four-stroke, or other engine designs having BDC and TDC
designations) can
occur at least partially concurrently with the closing of the intake valve. In
some embodiments,
moving the piston(s) or other features of the combustion chamber to accomplish
compression
can occur substantially concurrently with the induction of intake charge into
the combustion
chamber. In some embodiments, moving the piston(s) or other features of the
combustion
chamber to accomplish compression can occur with little or no overlap to the
induction of
intake charge into the combustion chamber.
[0046]
The method 10 includes injecting a volume of fuel into the combustion
chamber at
step 15. In some embodiments, the volume of fuel and the volume of intake
charge can be
introduced into the combustion chamber in a stoichiometric ratio. In some
embodiments, the
volume of fuel and the volume of intake charge can be introduced into the
combustion chamber
in a non-stoichiometric ratio.
[0047]
In some embodiments, the fuel can have a cetane number of at least about -
10, at
least about -5, at least about 0, at least about 5, at least about 10, atleast
about 15, at least about
20, at least about 25, at least about 30, or at least about 35. In some
embodiments, the fuel can
have a cetane number of no more than about 40, no more than about 35, no more
than about
30, no more than about 25, no more than about 20, no more than about 15, no
more than about
10, no more than about 5, no more than about 0, or no more than about -5.
Combinations of
the above-referenced cetane numbers of the fuel are also possible (e.g., at
least about -10 and
no more than about 40 or at least about 10 and no more than about 20),
inclusive of all values
and ranges therebetween. In some embodiments, the fuel can have a cetane
number of about -
10, about -5, about 0, about 5, about 10, about 15, about 20, about 25, about
30, about 35, or
about 40. In some embodiments, the fuel can include naphtha, gasoline,
alcohol, butanol,
propanol, ethanol, methanol, gaseous hydrocarbons, natural gas, methane,
ethane, propane,
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butane, hexane, alternative fuels, hydrogen, ammonia, syngas, and/or CO. In
some
embodiments, the fuel can include Cl (single carbon atom per molecule)
hydrocarbons, C2
(two carbon atoms per molecule) hydrocarbons, C3 hydrocarbons, C4
hydrocarbons, and/or
fuels having no carbon atoms. In some embodiments, the fuel can have a low
amount of
additives that result in a substantial change in cetane number. In some
embodiments, the fuel
can include a small amount of additives to modify lubricity or viscosity of
the fuel.
[0048]
In some embodiments, the fuel can include any blend or combination of any
of the
aforementioned fuels (e.g., methanol/ethanol, methane/ethane, methane/propane,

ethane/propane, m ethane/ethane/propane, methane/butane, ethane/butane,
propane/butane,
methane/ethane/butane, ethane/propane/butane,
methane/ethane/propane/butane,
hydrogen/syngas, hydrogen/CO). In some embodiments, the fuel can include any
blend or
combination of any of the aforementioned fuels with gasoline or any other high
hydrocarbon
fuels added thereto (e.g., methanol/ethanol + gasoline, methane/ethane +
gasoline,
methane/propane + gasoline, ethane/propane + gasoline, methane/ethane/propane
+ gasoline,
methane/butane + gasoline, ethane/butane + gasoline, propane/butane
gasoline,
methane/ethane/butane gasoline, ethane/propane/butane
gasoline,
methane/ethane/propane/butane + gasoline, hydrogen/syngas + gasoline,
hydrogen/CO +
gasoline). In some embodiments, the fuel can include blends of two or more of
the
aforementioned fuels.
[0049]
In some embodiments, the fuel can include less than about 5,000 ppm, less
than
about 4,000 ppm, less than about 3,000 ppm, less than about 2,000 ppm, less
than about 1,000
ppm, less than about 900 ppm, less than about 800 ppm, less than about 700
ppm, less than
about 600 ppm, or less than about 500 ppm by weight of additives that result
in a substantial
change in cetane number. In some embodiments, the fuel can be substantially
free of additives
that result in a substantial change in cetane number.
[0050]
In some embodiments, the fuel can include less than about 5,000 ppm, less
than
about 4,000 ppm, less than about 3,000 ppm, less than about 2,000 ppm, less
than about 1,000
ppm, less than about 900 ppm, less than about 800 ppm, less than about 700
ppm, less than
about 600 ppm, or less than about 500 ppm by weight of additives that result
in a substantial
change in lubricity or viscosity. In some embodiments, the fuel can be
substantially free of
additives that result in a substantial change in lubricity or viscosity.
[0051]
In some embodiments, the fuel can have an octane number (i.e., calculated
via
(RON + MON)/2 method) of at least about 50, at least about 55, at least about
60, at least about
65, at least about 70, at least about 75, at least about 80, at least about
85, at least about 90, at
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least about 95, at least about 100, at least about 105, at least about 110, at
least about 115, at
least about 120, at least about 125, at least about 130, at least about 135,
at least about 140, or
at least about 145. In some embodiments, the fuel can have an octane number of
no more than
about 150, no more than about 145, no more than about 140, no more than about
135, no more
than about 130, no more than about 125, no more than about 120, no more than
about 115, no
more than about 110, no more than about 105, no more than about 100, no more
than about 95,
no more than about 90, no more than about 85, no more than about 80, no more
than about 75,
no more than about 70, no more than about 65, no more than about 60, or no
more than about
55
Combinations of the above-referenced octane numbers are also possible (es,
at least about
50 and no more than about 150 or at least about 80 and no more than about 120,
inclusive of
all values and ranges therebetween. In some embodiments, the fuel can have an
octane number
of about 50, about 55, about 60, about 65, about 70, about 75, about 80, about
85, about 90,
about 95, about 100, about 105, about 110, about 115, about 120, about 125,
about 130, about
135, about 140, about 145, or about 150.
[0052]
In some embodiments, the fuel can have a flash point of at least about 0
C, at least
about 5 C, at least about 10 C, at least about 15 C, at least about 20 C,
at least about 25 C,
at least about 30 C, at least about 35 C, at least about 40 C, or at least
about 45 C. In some
embodiments, the fuel can have a flash point of no more than about 50 C, no
more than about
45 C, no more than about 40 C, no more than about 35 C, no more than about
30 C, no
more than about 25 C, no more than about 20 C, no more than about 15 C, no
more than
about 10 C, or no more than about 5 C. Combinations of the above-referenced
flash points
of the fuel are also possible (e.g., at least about 0 C and no more than
about 50 C or at least
about 10 C and no more than about 40 'V, inclusive of all values and ranges
therebetween. In
some embodiments, the fuel can have a flash point of about 0 C, about 5 C,
about 10 C,
about 15 C, about 20 C, about 25 C, about 30 C, about 35 C, about 40 C,
about 45 C, or
about 50 C.
[0053]
In some embodiments, the volume of fuel can be injected from a fuel
injector (e.g.,
the fuel injector 270, as described above with reference to FIG. 2) at an
injection pressure of at
least about 400 bar (absolute), at least about 500 bar, at least about 600
bar, at least about 700
bar, at least about 800 bar, at least about 900 bar, at least about 1,000 bar,
at least about 1,100
bar, at least about 1,200 bar, at least about 1,300 bar, at least about 1,400
bar, at least about
1,500 bar, at least about 1,600 bar, at least about 1,700 bar, at least about
1,800 bar, at least
about 1,900 bar, at least about 2,000 bar, at least about 2,100 bar, at least
about 2,200 bar, at
least about 2,300 bar, at least about 2,400 bar, at least about 2,500 bar, at
least about 2,600 bar,
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at least about 2,700 bar, at least about 2,800 bar, or at least about 2,900
bar. In some
embodiments, the volume of fuel can be injected from the fuel injector at an
injection pressure
of no more than about 3,000 bat, no more than about 2,900 bar, no more than
about 2,800 bar,
no more than about 2,700 bar, no more than about 2,600 bar, no more than about
2,500 bar, no
more than about 2,400 bar, no more than about 2,300 bar, no more than about
2,200 bar, no
more than about 2,100 bar, no more than about 2,000 bar, no more than about
1,900 bar, no
more than about 1,800 bar, no more than about 1,700 bar, no more than about
1,600 bar, no
more than about 1,500 bar, no more than about 1,400 bar, no more than about
1,300 bar, no
more than about 1,200 bar, no more than about 1,100 bar, no more than about
1,000 bar, no
more than about 900 bar, no more than about 800 bar, no more than about 700
bar, no more
than about 600 bar, no more than about 500 bar, no more than about 400 bar.
Combinations of
the above-referenced injection pressures are also possible (e.g., at least
about 400 bar and no
more than about 3,000 bar or at least about 1,200 bar and no more than about
2,000 bar),
inclusive of all values and ranges therebetween. In some embodiments, the fuel
can be injected
from the fuel injector at an injection pressure of about 800 bar, about 900
bar, about 1,000 bar,
about 1,100 bar, about 1,200 bar, about 1,300 bar, about 1,400 bar, about
1,500 bar, about 1,600
bar, about 1,700 bar, about 1,800 bar, about 1,900 bar, about 2,000 bar, about
2,100 bar, about
2,200 bar, about 2,300 bar, about 2,400 bar, about 2,500 bar, about 2,600 bar,
about 2,700 bar,
about 2,800 bar, about 2,900 bar, or about 3,000 bar.
[0054]
In some embodiments, the fuel can include a fuel with 1 carbon atom per
molecule
(e.g., methane, methanol, CO). In some embodiments, the fuel can be free of
carbon atoms
(e.g., hydrogen, ammonia). In some embodiments, the fuel can include a fuel
with at least
about 1 carbon atom per molecule, at least about 2 carbon atoms per molecule,
at least about 3
carbon atoms per molecule, at least about 4 carbon atoms per molecule, at
least about 5 carbon
atoms per molecule, at least about 6 carbon atoms per molecule, at least about
7 carbon atoms
per molecule, at least about 8 carbon atoms per molecule, or at least about 9
carbon atoms per
molecule. In some embodiments, the fuel can include a fuel with no more than
about 10 carbon
atoms per molecule, no more than about 9 carbon atoms per molecule, no more
than about 8
carbon atoms per molecule, no more than about 7 carbon atoms per molecule, no
more than
about 6 carbon atoms per molecule, no more than about 5 carbon atoms per
molecule, no more
than about 4 carbon atoms per molecule, no more than about 3 carbon atoms per
molecule, or
no more than about 2 carbon atoms per molecule. Combinations of the above-
referenced
numbers of carbon atoms per molecule are also possible (e.g., at least about 1
carbon atom per
molecule and no more than about 10 carbon atoms per molecule or at least about
1 carbon atom
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per molecule and no more than about 3 carbon atoms per molecule), inclusive of
all values and
ranges therebetween. In some embodiments, the fuel can include a fuel with
about 1 carbon
atom per molecule, about 2 carbon atoms per molecule, about 3 calbon atoms per
molecule,
about 4 carbon atoms per molecule, about 5 carbon atoms per molecule, about 6
carbon atoms
per molecule, about 7 carbon atoms per molecule, about 8 carbon atoms per
molecule, about 9
carbon atoms per molecule, or about 10 carbon atoms per molecule.
[0055]
In some embodiments, the volume of fuel can be injected at an engine crank
angle
(using four-stroke engine crank angle convention) of at least about 310
degrees, at least about
315 degrees, at least about 320 degrees, at least about 325 degrees, at least
about 330 degrees,
at least about 335 degrees, at least about 340 degrees, at least about 345
degrees, at least about
350 degrees, at least about 355 degrees, at least about 360 degrees, at least
about 365 degrees,
or at least about 370 degrees. In some embodiments, the volume of fuel can be
injected at an
engine crank angle of no more than about 375 degrees, no more than about 370
degrees, no
more than about 365 degrees, no more than about 360 degrees, no more than
about 355 degrees,
no more than about 350 degrees, no more than about 345 degrees, no more than
about 340
degrees, no more than about 335 degrees, no more than about 330 degrees, no
more than about
325 degrees, no more than about 320 degrees, or no more than about 315
degrees.
Combinations of the above-referenced engine crank angles at injection of the
volume of fuel
are also possible (e.g., at least about 310 degrees and no more than about 375
degrees or at
least about 330 degrees and no more than about 365 degrees), inclusive of all
values and ranges
therebetween. In some embodiments, the volume of fuel can be injected at an
engine crank
angle of about 310 degrees, about 315 degrees, about 320 degrees, about 325
degrees, about
330 degrees, about 335 degrees, about 340 degrees, about 345 degrees, about
350 degrees,
about 355 degrees, about 360 degrees, about 365 degrees, about 370 degrees, or
about 375
degrees
[0056]
In some embodiments, the volume of fuel can be injected at a time at least
about 10
ms prior to the end of the compression process, at least about 8 ms prior to
the end of the
compression process, at least about 6 ms prior to the end of the compression
process, at least
about 4 ms prior to the end of the compression process, at least about 2 ms
prior to the end of
the compression process, at least about 1 ms prior to the end of the
compression process, at
about the same time as the end of the compression process, at least about 1 ms
after the end of
the compression process, at least about 2 ms after the end of the compression
process, at least
about 4 ms after the end of the compression process, at least about 6 ms after
the end of the
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compression process, at least about 8ms after the end of the compression
process, at least about
ms after the end of the compression process.
[0057]
In some embodiments, the volume of fuel can be injected at a time of no
more than
about 10 ms after the end of the compression process, no more than about 8 ms
after the end
of the compression process, no more than about 6 ms after the end of the
compression process,
no more than about 4 ms after the end of the compression process, no more than
about 2 ms
after the end of the compression process, no more than about 1 ms after the
end of the
compression process, no more than about 1 ms prior to the end of the
compression process, no
more than about 2 ms prior to the end of the compression process, no more than
about 4 ms
prior to the end of the compression process, no more than about 6 ms prior to
the end of the
compression process, no more than about 8 ms prior to the end of the
compression process, or
no more than about 10 ms prior to the end of the compression process.
Combinations of the
above-referenced timing at injection of the volume of fuel are also possible
(e.g., at least about
10 ms prior and no more than about 2 ms after the end of the compression
process or at least
about 5ms prior to the end of the compression process and no more than about
lms after the
end of the compression process), inclusive of all values and ranges
therebetween. In some
embodiments, the volume of fuel can be injected at a timing with respect to
the end of the
compression process (t = 0) of about -10 ms, about -8 ms, about -6 ms, about -
4 ms, about -2
ms, about -1 ms, about 0 ms (or approximately coinciding with the end of the
compression
process), about 1 ms, about 2 ms, about 4 ms, about 6 ms, about 8 ms, or about
10 ms.
[0058]
In some embodiments, no more than 10% of the volume of fuel is injected
prior to
a crank angle degree (using four-stroke engine crank angle convention) of
about 310 degrees,
about 315 degrees, about 320 degrees, about 325 degrees, about 330 degrees,
about 335
degrees, about 340 degrees, about 345 degrees, about 350 degrees, about 355
degrees, about
360 degrees, about 365 degrees, about 370 degrees, about 375 degrees, about
380 degrees,
about 385 degrees, or about 390 degrees, inclusive of all values and ranges
therebetween.
[0059]
In some embodiments, no more than 10% of the volume of fuel is injected
prior to
a timing in the engine cycle, with respect to the end of the compression
process (t = 0) of about
-10 ms, about -8 ms, about -6 ms, about -4 ms, about -2 ms, about -1 ms,
approximately
coinciding with the end of the compression process Oms, about 1 ms, about 2
ms, about 4 ms,
about 6 ms, about 8 ms, about 10 ms, inclusive of all values and ranges
therebetween.
[0060]
In some embodiments, injection of the volume of fuel can occur at least
partially
concurrently with moving the piston from BDC to TDC (in the case of two
stroke, four stroke,
or other engine designs having BDC and TDC designations). In some embodiments,
injection
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of the volume of fuel can occur substantially concurrently with moving the
piston from BDC
to TDC. In some embodiments, injection of the volume of fuel can occur with
little or no
overlap to moving the piston from BDC to TDC.
[0061]
In some embodiments, injection of the volume of fuel can occur at least
partially
concurrently with compressing the charge inside the combustion chamber. In
some
embodiments, injection of the volume of fuel can occur substantially
concurrently with
compressing the charge inside the combustion chamber. In some embodiments,
injection of
the volume of fuel can occur with little or no overlap to the compression
process.
[0062]
In some embodiments, injection of the volume of fuel can be modified to
control
the rate of pressure rise in the combustion chamber from combustion of the
volume of fuel.
Pressure rise rate is often treated as a constraint in engines in attempting
to minimize engine
noise and vibration. Some alternative combustion strategies (e.g., homogeneous
charge
compression ignition engines) can struggle to minimize pressure rise rate,
particularly at high
loads. Embodiments described herein relate to methods of controlling pressure
rise rate by
controlling the rate of combustion (i.e., by controlling mixing and injection
in a mixing-limited
system). In other words, pressure rise rate can be as low as desired to reduce
noise and
vibration, and controlled in the same manner as a conventional diesel engine.
[0063]
In some embodiments, the rate of pressure rise can be less than about 15
bar per
crank angle degree, less than about 14 bar per crank angle degree, less than
about 13 bar per
crank angle degree, less than about 12 bar per crank angle degree, less than
about 11 bar per
crank angle degree, less than about 10 bar per crank angle degree, less than
about 9 bar per
crank angle degree, less than about 8 bar per crank angle degree, less than
about 7 bar per crank
angle degree, less than about 6 bar per crank angle degree, less than about 5
bar per crank angle
degree, less than about 4 bar per crank angle degree, less than about 3 bar
per crank angle
degree, less than about 2 bar per crank angle degree, or less than about 1 bar
per crank angle
degree, inclusive of all values and ranges therebetween. In some embodiments,
controlling the
rate of pressure rise can be done independently from changing the injection
timing of the
volume of fuel. In some embodiments, controlling the rate of pressure rise
from the combustion
chamber can be exclusively via changing the injection timing of the volume of
fuel. In some
embodiments, injection timing can be changed by an engine control unit using
either electrical
or hydraulic means to trigger fuel injector opening at a desired time to shift
timing either earlier
or later. In some embodiments, injection timing can be changed mechanically
based on a
mechanical linkage to a cam or other device in response to changing operating
conditions such
as engine speed.
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[0064]
In some embodiments, the rate of pressure rise can be less than about 36
MPa/ms,
less than about 34 MPa/ms, less than about 32 MPa/ms, less than about 30
MPa/ms, less than
about 28 MPa/ms, less than about 26 MPa/ms, less than about 24 MPanns, less
than about 22
MPa/ms, less than about 20 MPa/ms, less than about 18 MPa/ms, less than about
16 MPa/ms,
less than about 14 MPa/ms, less than about 12 MPa/ms, less than about 10
MPa/ms, less than
about 8 MPa/ms, less than about 6 MPa/ms, less than about 4 MPa/ms, less than
about 2
MPa/ms, or less than about 1 MPa/ms, inclusive of all values and ranges
therebetween.
[0065]
In some embodiments, controlling the rate of pressure rise can be done
independently from changing the inj ecti on timing of the volume of fuel In
some embodiments,
controlling the rate of pressure rise from the combustion chamber can be
exclusively via
changing the injection timing of the volume of fuel. In some embodiments,
injection timing
can be changed by an engine control unit using either electrical or hydraulic
means to trigger
fuel injector opening at a desired time to shift timing either earlier or
later. In some
embodiments, injection timing can be changed mechanically based on a
mechanical linkage to
a cam or other device in response to changing operating conditions such as
engine speed.
[0066]
The method 10 includes combusting the volume of fuel at step 16. In some
embodiments, combusting the volume of fuel at step 16 can occur at least
partially concurrently
with injecting the fuel into the combustion chamber at step 15. In some
embodiments, step 16
can include combusting substantially all of the volume of fuel. In some
embodiments, the
volume-average temperature in the combustion chamber immediately prior to
ignition can be
at least about 500 K, at least about 550 K, at least about 600 K, at least
about 650 K, at least
about 700 K, at least about 750 K, at least about 800 K, at least about 850 K,
at least about 900
K, at least about 950 K, at least about 1,000 K, at least about 1,050 K, at
least about 1,100 K,
at least about 1,150 K, at least about 1,200 K, at least about 1,250 K, at
least about 1,300 K, at
least about 1,350 K, at least about 1,400 K, or at least about 1,500 K. In
some embodiments,
the volume-average temperature in the combustion chamber immediately prior to
ignition can
be no more than about 1,500 K, no more than about 1,450 K, no more than about
1,400 K, no
more than about 1,350 K, no more than about 1,300 K, no more than about 1,250
K, no more
than about 1,200 K, no more than about 1,150 K, no more than about 1,100 K, no
more than
about 1,050 K, no more than about 1,000 K, no more than about 950 K, no more
than about
900 K, no more than about 850 K, no more than about 800 K, no more than about
750 K, no
more than about 700 K, no more than about 650 K, no more than about 600 K, or
no more than
about 550 K. Combinations of the above-referenced volume-average temperatures
in the
combustion chamber immediately prior to ignition are also possible (e.g., at
least about 500 K
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and no more than about 1,500 K or at least about 700 K and no more than about
1,100 K),
inclusive of all values and ranges therebetween. In some embodiments, the
volume-average
temperature in the combustion chamber immediately prior to ignition can be
about 500 K, about
550 K, about 600 K, about 650 K, about 700 K, about 750 K, about 800 K, about
850 K, about
900K, about 950K, about 1,000K, about 1,050K, about 1,100 K, about 1,150K,
about 1,200
K, about 1,250 K, about 1,300 K, about 1,350K, about 1,400 K, or about 1,500 K
[0067]
In some embodiments, the volume-average temperature in the combustion
chamber
immediately prior to ignition can be a function of the cetane number of the
fuel. In some
embodiments, if the fuel has a cetane number between about 30 and about 40,
the volume-
average temperature in the combustion chamber immediately prior to ignition
can be at least
about 700 K, at least about 750 K, at least about 800 K, at least about 850 K,
at least about 900
K, at least about 950K, at least about 1,000 K, at least about 1,050 K, at
least about 1,100 K,
at least about 1,150 K, at least about 1,200 K, or at least about 1,250K. In
some embodiments,
if the fuel has a cetane number between about 30 and about 40, the volume-
average temperature
in the combustion chamber immediately prior to ignition can be no more than
about 1,300 K,
no more than about 1,250 K, no more than about 1,200 K, no more than about
1,150 K, no
more than about 1,100 K, no more than about 1,050 K, no more than about 1,000
K, no more
than about 950 K, no more than about 900 K, no more than about 850 K, no more
than about
800 K, or no more than about 750 K. Combinations of the above-referenced
volume-average
temperatures in the combustion chamber immediately prior to ignition are also
possible (e.g.,
at least about 700 K and no more than about 1,300 K or at least about 800 K
and no more than
about 1,000 K), inclusive of all values and ranges therebetween. In some
embodiments, if the
fuel has a cetane number between about 30 and about 40, the volume-average
temperature in
the combustion chamber immediately prior to ignition can be about 700 K, about
750 K, about
800 K, about 850 K, about 900 K, about 950 K, about 1,000 K, about 1,050 K,
about 1,100 K,
about 1,150 K, about 1,200 K, about 1,250 K, or about 1,300 K.
[0068]
In some embodiments, if the fuel has a cetane number between about 20 and
about
30, the volume-average temperature in the combustion chamber immediately prior
to ignition
can be at least about 800 K, at least about 850 K, at least about 900 K, at
least about 950 K, at
least about 1,000 K, at least about 1,050 K, at least about 1,100 K, at least
about 1,150 K, at
least about 1,200 K, at least about 1,250 K, at least about 1,300 K, or at
least about 1,350 K.
In some embodiments, if the fuel has a cetane number between about 20 and
about 30, the
volume-average temperature in the combustion chamber immediately prior to
ignition can be
no more than about 1,400 K, no more than about 1,350 K, no more than about
1,300 K, no
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more than about 1,250 K, no more than about 1,200 K, no more than about 1,150
K, no more
than about 1,100 K, no more than about 1,050 K, no more than about 1,000 K, no
more than
about 950 K, no more than about 900 K, or no more than about 850 K.
Combinations of the
above-referenced volume-average temperatures in the combustion chamber
immediately prior
to ignition are also possible (e.g., at least about 800 K and no more than
about 1,400 K or at
least about 900 K and no more than about 1,100 K), inclusive of all values and
ranges
therebetween. In some embodiments, if the fuel has a cetane number between
about 20 and
about 30, the volume-average temperature in the combustion chamber immediately
prior to
ignition can be about 800 K, about 850 K, about 900 K, about 950 K, about
1,000 K, about
1,050 K, about 1,100 K, about 1,150 K, about 1,200 K, about 1,250 K, about
1,300 K, about
1,350 K, or about 1,400 K.
[0069]
In some embodiments, if the fuel has a cetane number between about 10 and
about
20, the volume-average temperature in the combustion chamber immediately prior
to ignition
can be at least about 850 K, at least about 900 K, at least about 950 K, at
least about 1,000 K,
at least about 1,050 K, at least about 1,100 K, at least about 1,150 K, at
least about 1,200 K, at
least about 1,250 K, at least about 1,300 K, at least about 1,350 K, or at
least about 1,400 K.
In some embodiments, if the fuel has a cetane number between about 10 and
about 20, the
volume-average temperature in the combustion chamber immediately prior to
ignition can be
no more than about 1,450 K, no more than about 1,400 K, no more than about
1,350 K, no
more than about 1,300 K, no more than about 1,250 K, no more than about 1,200
K, no more
than about 1,150 K, no more than about 1,100 K, no more than about 1,050 K, no
more than
about 1,000 K, no more than about 950 K, or no more than about 900 K.
Combinations of the
above-referenced volume-average temperatures in the combustion chamber
immediately prior
to ignition are also possible (e.g., at least about 850 K and no more than
about 1,450 K or at
least about 950 K and no more than about 1,150 K), inclusive of all values and
ranges
therebetween. In some embodiments, if the fuel has a cetane number between
about 10 and
about 20, the volume-average temperature in the combustion chamber immediately
prior to
ignition can be about 850 K, about 900 K, about 950 K, about 1,000 K, about
1,050 K, about
1,100 K, about 1,150 K, about 1,200 K, about 1,250 K, about 1,300 K, about
1,350 K, about
1,400 K, or about 1,450 K.
[0070]
In some embodiments, if the fuel has a cetane number between about 0 and
about
10, the volume-average temperature in the combustion chamber immediately prior
to ignition
can be at least about 950 K, at least about 1,000 K, at least about 1,050 K,
at least about 1,100
K, at least about 1,150K, at least about 1,200K, at least about 1,250K, at
least about 1,300K,
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at least about 1,350 K, at least about 1,400 K, at least about 1,450 K, or at
least about 1,500 K.
In some embodiments, if the fuel has a cetane number between about 0 and about
10, the
volume-average temperature in the combustion chamber immediately prior to
ignition can be
no more than about 1,550 K, no more than about 1,500 K, no more than about
1,450 K, no
more than about 1,400 K, no more than about 1,350 K, no more than about 1,300
K, no more
than about 1,250 K, no more than about 1,200 K, no more than about 1,150 K, no
more than
about 1,100K, no more than about 1,050 K, or no more than about 1,000 K.
Combinations of
the above-referenced volume-average temperatures in the combustion chamber
immediately
prior to ignition are also possible (e g , at least about 950 K and no more
than about 1,550 K or
at least about 1,050 K and no more than about 1,250 K), inclusive of all
values and ranges
therebetween. In some embodiments, if the fuel has a cetane number between
about 0 and
about 10, the volume-average temperature in the combustion chamber immediately
prior to
ignition can be about 950 K, about 1,000 K, about 1,050 K, about 1,100 K,
about 1,150 K,
about 1,200 K, about 1,250 K, about 1,300 K, about 1,350 K, about 1,400 K,
about 1,450 K,
about 1,500 K, or about 1,550 K.
[0071]
In some embodiments, if the fuel has a cetane number less than about 0, the
volume-
average temperature in the combustion chamber immediately prior to ignition
can be at least
about 1,050 K, at least about 1,100 K, at least about 1,150 K, at least about
1,200 K, at least
about 1,250 K, at least about 1,300 K, at least about 1,350 K, at least about
1,400 K, at least
about 1,450 K, at least about 1,500 K, at least about 1,550 K, or at least
about 1,600 K. In
some embodiments, if the fuel has a cetane number less than about 0, the
volume-average
temperature in the combustion chamber immediately prior to ignition can be no
more than
about 1,650 K, no more than about 1,600 K, no more than about 1,550 K, no more
than about
1,400 K, no more than about 1,450 K, no more than about 1,400 K, no more than
about 1,350
K, no more than about 1,300 K, no more than about 1,250 K, no more than about
1,200 K, no
more than about 1,150 K, or no more than about 1,100 K. Combinations of the
above-
referenced volume-average temperatures in the combustion chamber immediately
prior to
ignition are also possible (e.g., at least about 1,050 K and no more than
about 1,650 K or at
least about 1,150 K and no more than about 1,350 K), inclusive of all values
and ranges
therebetween. In some embodiments, if the fuel has a cetane number of less
than about 0, the
volume-average temperature in the combustion chamber immediately prior to
ignition can be
about 1,050 K, about 1,100 K, about 1,150 K, about 1,200 K, about 1,250 K,
about 1,300 K,
about 1,350 K, about 1,400 K, about 1,450 K, about 1,500 K, about 1,550 K,
about 1,600 K,
or about 1,650 K.
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[0072]
In some embodiments, less than 50% of the volume of fuel can be pre-mixed
with
the volume of intake charge upon initiation of combustion. In other words, the
ignition of the
volume of fuel can be fluxing controlled, or MCCI. In some embodiments, the
fuel can include
gasoline, and the ignition of the volume of fuel can include MCCI of gasoline
(i.e., not HCCI
of gasoline, nor HCCI of any other fuel). In some embodiments, at least about
5%, at least
about 10%, at least about 15%, at least about 20%, at least about 25%, at
least about 30%, at
least about 35%, at least about 40%, or at least about 45% of the volume of
fuel can be pre-
mixed with the volume of intake charge upon initiation of combustion. In some
embodiments,
no more than about 50%, no more than about 45%, no more than about 40%, no
more than
about 35%, no more than about 30%, no more than about 25%, no more than about
20%, no
more than about 15%, or no more than about 10% of the volume of fuel can be
pre-mixed with
the volume of intake charge upon initiation of combustion. Combinations of the
above-
referenced percentages of the volume of fuel pre-mixed with the volume of
intake charge are
also possible (e.g., at least about 5% and no more than about 50% or at least
about 10% and no
more than about 40%), inclusive of all values and ranges therebetween. In some
embodiments,
about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%,
about 40%,
about 45%, or about 50% of the volume of fuel can be pre-mixed with the volume
of intake
charge upon initiation of combustion. In some embodiments, the local
equivalence ratio at
points within the combustion chamber can be at least about 1.5, at least about
2, at least about
3, at least about 4, at least about 5, at least about 6, at least about 7, at
least about 8, at least
about 9, or at least about 10, inclusive of all values and ranges
therebetween.
[0073]
In some embodiments, at least about 25% of the energy generated from
combustion
of the volume of fuel can be generated while the volume of fuel is being
injected into the
combustion chamber. In some embodiments, at least about 30% of the energy
generated from
combustion of the volume of fuel can be generated while the volume of fuel is
being injected
into the combustion chamber. In some embodiments, at least about 35%, at least
about 40%,
at least about 45%, at least about 50%, at least about 55%, at least about
60%, at least about
65%, at least about 70%, at least about 75%, at least about 80%, at least
about 85%, or at least
about 90% of the energy generated from combustion of the volume of fuel can be
generated
while the volume of fuel is being injected into the combustion chamber. In
some embodiments,
no more than about 95%, no more than about 90%, no more than about 85%, no
more than
about 80%, no more than about 75%, no more than about 70%, no more than about
65%, no
more than about 60%, no more than about 55%, no more than about 50%, no more
than about
45%, no more than about 40%, no more than about 35%, or no more than about 30%
of the
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energy generated from combustion of the volume of fuel can be generated while
the volume of
fuel is being injected into the combustion chamber. Combinations of the above-
referenced
percentages of the energy generated from combustion of the volume of fuel can
be generated
while the volume of fuel is being injected into the combustion chamber (e.g.,
at least about
40% and no more than about 95% or at least about 60% and no more than about
80%), inclusive
of all values and ranges therebetween. In some embodiments, about 25%, about
30%, about
35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about
70%, about
75%, about 80%, about 85%, about 90%, or about 95% of the energy generated
from
combustion of the volume of fuel can be generated while the volume of fuel is
being injected
into the combustion chamber.
[0074]
In some embodiments, the volume of intake charge can have a temperature of
at
least about 80 C, at least about 90 C, at least about 100 C, at least about
150 C, at least
about 200 C, at least about 250 'V, at least about 300 "V, at least about 350
'V, at least about
400 C, at least about 450 'V, at least about 500 C, at least about 550 C,
at least about 600
C, at least about 650 C, at least about 700 C, or at least about 750 C upon
initially being
drawn into the combustion chamber. In some embodiments, the volume of intake
charge can
have a temperature of no more than about 800 C, no more than about 750 C, no
more than
about 700 C, no more than about 650 C, no more than about 600 C, no more
than about 550
CC, no more than about 500 CC, no more than about 450 CC, no more than about
400 C, no
more than about 350 C, no more than about 300 C, no more than about 250 C,
no more than
about 200 C, no more than about 150 C, no more than about 100 C, or no more
than about
90 C upon initially being drawn into the combustion chamber. Combinations of
the above-
referenced temperatures of the volume of intake charge upon initially being
drawn into the
combustion chamber are also possible (e.g., at least about 80 C and no more
than about 800
C or at least about 200 C and no more than about 600 C), inclusive of all
values and ranges
therebetween. In some embodiments, the volume of intake charge can have a
temperature of
about 80 C, about 90 C, about 100 C, about 150 C, about 200 C, about 250
C, about 300
C, about 350 C, about 400 C, about 450 C, about 500 C, about 550 C, about
600 C,
about 650 'V, about 700 'V, about 750 C, or about 800 C upon initially being
drawn into the
combustion chamber. In some embodiments, the volume of fuel can produce, upon
continued
injection, a mixing-limited plume. In some embodiments, the volume of fuel and
the volume
of intake charge can combine in a chemical reaction in the mixing-limited
plume.
[0075]
In some embodiments, a delay between the initial injection of the volume of
fuel
into the combustion chamber and the onset of combustion can be less than about
5 ms, less
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than about 4.9 ms, less than about 4.8 ms, less than about 4.7 ms, less than
about 4.6 ms, less
than about 4.5 ms, less than about 4.4 ms, less than about 4.3 ms, less than
about 4.2 ms, less
than about 4.1 ms, less than about 4 ms, less than about 3.9 ins, less than
about 3.8 ms, less
than about 3.7 ms, less than about 3.6 ms, less than about 3.5 ms, less than
about 3.4 ms, less
than about 3.3 ms, less than about 3.2 ms, less than about 3.1 ms, less than
about 3 ms, less
than about 2.9 ms, less than about 2.8 ms, less than about 2.7 ms, less than
about 2.6 ms, less
than about 2.5 ms, less than about 2.4 ms, less than about 2.3 ms, less than
about 2.2 ms, less
than about 2.1 ms, less than about 2 ms, less than about 1.9 ms, less than
about 1.8 ms, less
than about 1.7 ms, less than about 1.6 ms, less than about 1.5 ms, less than
about 1.4 ms, less
than about 1.3 ms, less than about 1.2 ms, less than about 1.1 ms, less than
about 1 ms, less
than about 0.9 ms, less than about 0.8 ms, less than about 0.7 ms, less than
about 0.6 ms, or
less than about 0.5 ms, inclusive of all values and ranges therebetween.
[0076]
In some embodiments, the method 10 can include opening and closing the
exhaust
valve to exhaust combusted fuel, uncombusted fuel, excess air, and/or other
gases or liquids.
In some embodiments, the exhaust process to expel combusted fuel, uncombusted
fuel, excess
air, and/or other gases or liquids can take place in absence of an exhaust
valve. Opening or
closing the exhaust valve can be pertinent to engine designs that include an
exhaust valve (e.g.,
some four-stroke engine designs), but can be irrelevant to engine designs
without an exhaust
valve (e.g. some two-stroke engine designs). In some embodiments, the exhaust
process can
be started at a time, relative to the end of the work extraction process, of
at least about is prior
to the end of the work extraction process, at least about 750 ms prior to the
end of the work
extraction process, at least about 500 ms prior to the end of the work
extraction process, at least
about 250 ms prior to the end of the work extraction process, at least about
100 ms prior to the
end of the work extraction process, at least about 50 ms prior to the end of
the work extraction
process, at least about 10 ms prior to the end of the work extraction process,
at least about 5
ms prior to the end of the work extraction process, at least about 2 ms prior
to the end of the
work extraction process, at least about 1 ms prior to the end of the work
extraction process,
approximately coincident with the end of the work extraction process, at least
about 1 ms after
the end of the work extraction process, at least about 2 ms after the end of
the work extraction
process, at least about 5 ms after the end of the work extraction process, at
least about 10 ms
after the end of the work extraction process, at least about 25ms after the
end of the work
extraction process, at least about 50 ms after the end of the work extraction
process, at least
about 100 ms after the end of the work extraction process, at least about 250
ms after the end
of the work extraction process, at least about 500 ms after the end of the
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process, at least about 750 ms after the end of the work extraction process,
or at least about is
after the end of the work extraction process. In some embodiments, the exhaust
process can
begin at least about 1 second, at least about 750 ms, at least about 500 ins,
at least about 250
ms, at least about 100 ms, at least about 50 ms, at least about 25 ms, at
least about 10 ms, at
least about 5 ms, at least about 2 ms, or at least about 1 ms prior to the end
of the work extraction
process.
[0077]
In some embodiments the exhaust process can begin at no more than about lms
after the work extraction process, no more than about 2 ms after the work
extraction process,
no more than about 5 ms after the work extraction process, no more than about
10 ms after the
work extraction process, no more than about 25 ms after the work extraction
process, no more
than about 50 ms after the work extraction process, no more than about 100 ms
after the work
extraction process, no more than about 250 ms after the work extraction
process, no more than
about 500 ms after the work extraction process, no more than about 750 ms
after the work
extraction process, or no more than about 1 second after the work extraction
process.
Combinations of the above-referenced timing for beginning the exhaust process
are also
possible (e.g., at least about 10 ms before and no more than about 750 ms
before conclusion of
the work extraction, or at least about 50 ms and no more than about 100 ms
before conclusion
of the work extraction), inclusive of all values and ranges therebetween. In
some embodiments,
the exhaust valve can be opened at about 1 second, about 750 ms, about 500 ms,
about 250 ms,
about 100 ms, about 50 ms, about 25 ms, about 10 ms, about 5 ms, about 2 ms,
about or about
1 ms prior to the end of the work extraction, or about 1 ms, about 2 ms, about
5 ms, about 10
ms, about 25 ms, about 50 ms, about 100 ms, about 250 ms, about 500 ms, about
750 ms, or
about 1 second after the end of the work extraction process.
[0078]
In some embodiments, the closing of the exhaust valve can be timed to trap
exhaust
gas in the combustion chamber to aid in thermal management. In some
embodiments, the
closing of the exhaust valve can be timed to re-introduce exhaust gas into the
combustion
chamber to aid in thermal management. In some embodiments (using four-stroke
engine crank
angle convention), the exhaust valve can be closed at an engine crank angle of
at least about -
20 , at least about -15 , at least about -10 , at least about -5 , at least
about 0 , at least about
50, or at least about 10 . In some embodiments, the exhaust valve can be
closed at an engine
crank angle of no more than about 150, no more than about 100, no more than
about 5 , no
more than about 0 , no more than about -5 , no more than about -10 , or no
more than about -
IS . Combinations of the above-referenced engine crank angles for the closing
of the exhaust
valve are also possible (e.g., at least about -20 and/or no more than about
150 or at least about
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-10 and no more than about 5 ), inclusive of all values and ranges
therebetween. In some
embodiments, the exhaust valve can be closed at an engine crank angle of about
-20 , about -
IS', about -10', about -5', about 0', about 5', about 10', or about 15'
[0079]
In some embodiments, the method 10 can include injecting and combusting
additional fuel at step 17. In some embodiments, a first fuel can be injected
during step 15,
and a second fuel can be injected during step 17, the second fuel having a
different cetane
number, heating value, and/or chemical composition from the first fuel. In
some embodiments,
the second fuel can be injected during a different engine cycle than the first
fuel. In some
embodiments, the second fuel can be subject to the same or substantially
similar steps as those
described above with reference to the first fuel. In other words, the method
10 can include
receiving a second volume of intake charge into the combustion chamber,
optionally applying
a temperature control strategy, closing the intake valve, moving the piston
from BDC to TDC,
injecting a volume of the second fuel into the combustion chamber, and
combusting
substantially all of the volume of the second fuel. In some embodiments, the
second fuel can
be subject to the same or substantially similar parameters (e.g., engine crank
angle upon fuel
injection, pressure of fuel upon injection, ignition delay, etc.) as those
described above with
reference to the first fuel.
[0080]
In some embodiments, the volume of intake charge received at step 11 can
have a
first temperature just prior to the injection of the first fuel (i.e., 0.5 ms,
1 ms, 1.5 ms, or 2 ms
prior to the beginning of the injection of the first fuel). In some
embodiments, the second
volume of intake charge can have a second temperature just prior to the
injection of the second
fuel. In some embodiments, the second temperature can be greater than the
first temperature
by about 1 `V, about 2 C, about 3 C, about 4 C, about 5 'V, about 6 C,
about 7 C, about 8
C, about 9 C, about 10 C, about 15 C, about 20 C, about 25 C, about 30
C, about 35 C,
about 40 C, about 45 C, about 50 C, about 60 C, about 70 C, about 80 C,
about 90 C, or
about 100 C.
[0081]
In some embodiments, the second fuel can have a different cetane number
from the
first fuel. In some embodiments, the second fuel can have a higher cetane
number than the first
fuel. In some embodiments, the second fuel can have a lower cetane number than
the first fuel.
In some embodiments, the second fuel can have a cetane number of at least
about -5, at least
about 0, at least about 5, at least about 10, at least about 15, at least
about 20, at least about 25,
at least about 30, at least about 35, at least about 40, at least about 45, at
least about 50, at least
about 55, at least about 60, or at least about 65. In some embodiments, the
second fuel can
have a cetane number of no more than about 70, no more than about 65, no more
than about
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60, no more than about 55, no more than about 50, no more than about 45, no
more than about
40, no more than about 35, no more than about 30, no more than about 25, no
more than about
20, no more than about 15, no more than about 10, no more than about 5, or no
more than about
0. Combinations of the above-referenced cetane numbers of the second fuel are
also possible
(e.g., at least about -5 and no more than about 70 or at least about 20 and no
more than about
50), inclusive of all values and ranges therebetween. In some embodiments, the
second fuel
can have a cetane number of about -5, about 0, about 5, about 10, about 15,
about 20, about 25,
about 30, about 35, about 40, about 45, about 50, about 55, about 60, about
65, or about 70.
100821
In some embodiments, the second fuel can have a different octane number
from the
first fuel. In some embodiments, the second fuel can have a lower octane
number than the first
fuel. In some embodiments, the second fuel can have a higher octane number
than the first
fuel. In some embodiments, the second fuel can have an octane number of at
least about 40, at
least about 45, at least about 50, at least about 55, at least about 60, at
least about 65, at least
about 70, at least about 75, at least about 80, at least about 85, at least
about 90, at least about
95, at least about 100, at least about 105, at least about 110, at least about
115, at least about
120, at least about 125, at least about 130, or at least about 135. In some
embodiments, the
fuel can have an octane number of no more than about 140, no more than about
135, no more
than about 130, no more than about 125, no more than about 120, no more than
about 115, no
more than about 110, no more than about 105, no more than about 100, no more
than about 95,
no more than about 90, no more than about 85, no more than about 80, no more
than about 75,
no more than about 70, no more than about 65, no more than about 60, no more
than about 55,
no more than about 50, or no more than about 45. Combinations of the above-
referenced octane
numbers are also possible (e.g., at least about 40 and no more than about 140
or at least about
70 and no more than about 110, inclusive of all values and ranges
therebetween. In some
embodiments, the fuel can have an octane number of about 40, about 45, about
50, about 55,
about 60, about 65, about 70, about 75, about 80, about 85, about 90, about
95, about 100,
about 105, about 110, about 115, about 120, about 125, about 130, about 135,
or about 140.
100831
In some embodiments, a sensor can adjust conditions in the engine based on
the
fuel being injected. In some embodiments, the sensor can have the same or
substantially similar
properties to the sensor 272, as described above with reference to FIG. 2. In
some
embodiments, conditions of the combustion can be adjusted based on the type of
fuel being
injected. In some embodiments, the parameters of the temperature control
mechanism can be
modified based on the type of fuel being injected. For example, if the second
fuel has a higher
cetane number than the first fuel, the intensity of the heat applied to the
volume of intake charge
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prior to injection can be reduced, as the temperature inside the combustion
chamber would not
have to be as high to facilitate a timely ignition (e.g., less than about 2
ms) of the second fuel.
In some embodiments, the crank angle at fuel injection can be modified based
on the type of
fuel being injected. In some embodiments, the composition of the volume of
intake charge
drawn into the combustion chamber can change based on the type of fuel being
injected. For
example, a fuel with a higher cetane number may not have to be mixed with a
volume of intake
charge with as high of a level of oxygen enrichment as a lower cetane fuel in
order to ignite
timely. In some embodiments, the pressure in the combustion chamber can be
modified based
on the type of fuel being injected.
[0084]
In some embodiments, the first fuel can be injected during a first time
period and
the second fuel can be injected during a second time period. In some
embodiments, the first
time period can have substantially no overlap with the second time period. In
some
embodiments, the first time period can have a partial overlap with the second
time period. In
other words, the first fuel can be phased out while the second fuel is phased
in. In some
embodiments, the first time period can have a substantial overlap with the
second time period.
In some embodiments, an overlap period between the first time period and the
second time
period can be at least about 0.1 seconds, at least about 0.2 seconds, at least
about 0.3 seconds,
at least about 0.4 seconds, at least about 0.5 seconds, at least about 0.6
seconds, at least about
0.7 seconds, at least about 0.8 seconds, at least about 0.9 seconds, at least
about 1 second, at
least about 2 seconds, at least about 3 seconds, at least about 4 seconds, at
least about 5 seconds,
at least about 6 seconds, at least about 7 seconds, at least about 8 seconds,
or at least about 9
seconds. In some embodiments, the overlap period between the first time period
and the second
time period can be no more than about 10 seconds, no more than about 9
seconds, no more than
about 8 seconds, no more than about 7 seconds, no more than about 6 seconds,
no more than
about 5 seconds, no more than about 4 seconds, no more than about 3 seconds,
no more than
about 2 seconds, no more than about 1 second, no more than about 0.9 seconds,
no more than
about 0.8 seconds, no more than about 0.7 seconds, no more than about 0.6
seconds, no more
than about 0.5 seconds, no more than about 0.4 seconds, no more than about 0.3
seconds, or no
more than about 0.2 seconds. Combinations of the above-referenced overlap
periods between
the first time period and the second time period are also possible (e.g., at
least about 0.1 seconds
and no more than about 10 seconds or at least about 0.3 seconds and no more
than about 0.5
seconds), inclusive of all values and ranges therebetween. In some
embodiments, the overlap
period between the first time period and the second time period can be about
0.1 seconds, about
0.2 seconds, about 0.3 seconds, about 0.4 seconds, about 0.5 seconds, about
0.6 seconds, about
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0.7 seconds, about 0.8 seconds, about 0.9 seconds, about 1 second, about 2
seconds, about 3
seconds, about 4 seconds, about 5 seconds, about 6 seconds, about 7 seconds,
about 8 seconds,
about 9 seconds, or about 10 seconds.
[0085]
In some embodiments, the method 10 can further include injecting and
combusting
a third fuel, the third fuel different from the first fuel and the second
fuel. In some
embodiments, the method 10 can include injecting and combusting a fourth, a
fifth, a sixth, a
seventh, an eighth, a ninth, a tenth fuel, an eleventh fuel, a twelfth fuel, a
thirteenth fuel, a
fourteenth fuel, a fifteenth fuel, a sixteenth fuel, a seventeenth fuel, an
eighteenth fuel, a
nineteenth fuel, a twentieth fuel, or any number of additional fuels
[0086]
In some embodiments, the high-temperature fuel-agnostic strategy described
herein
can be implemented on an engine having ports for intake and exhaust processes,
which are
uncovered based on piston movement or based on movement of other components
such as the
"sleeve valve" design of a Cleeves cycle engine.
[0087]
In some embodiments, the high-temperature fuel-agnostic strategy described
herein
can be implemented on an opposed piston engine, having two or more pistons
working together
to compress the gas through their combined motion, and to extract work through
their combined
motion. The opposed piston motion can be symmetric or asymmetric, and the
intake and
exhaust processes can proceed with or without conventional valves, ports,
sleeve valves, or
other means of blocking and unblocking a path for intake and exhaust
processes.
[0088]
In some embodiments, the high-temperature fuel-agnostic strategy described
herein
can be implemented in a free piston engine, where the piston is not coupled to
a crank shaft
directly, but rather moves freely in the combustion chamber, often coupled
electromagnetically
to a linear motor system to impart motion upon the piston and to extract
electrical work
resulting from the combustion. An example of a free piston architecture is
that developed by
Miller, Svrcek, Edwards, later commercialized by Main spring (originally
Etagen).
[0089]
In some embodiments, the high-temperature fuel-agnostic strategy described
herein
can be implemented in a non-conventional four-stroke or two-stroke
architecture such as an
engine employing an Atkinson linkage, Miller valve timing, or other methods to
accomplish
an asymmetric compression and expansion stroke.
[0090]
In some embodiments, the high-temperature fuel-agnostic strategy described
herein
can be implemented in a low-speed engine, having rpm lower than about 200 rpm.
In some
embodiments, the high-temperature fuel-agnostic strategy described herein can
be
implemented in a high-speed engine, having rpm higher than about 3000 rpm.
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[0091]
In some embodiments, the high-temperature fuel-agnostic strategy described
herein
can be coupled to additional exhaust or other thermal energy extraction
devices such as waste
heat recovery (wherein a working fluid is used in a create additional work
using thermal energy
from the exhaust to run a thermodynamic cycle such as a Brayton, Stirling,
Rankine, or other
cycle).
[0092]
In some embodiments, the high-temperature fuel-agnostic strategy described
herein
can include a turbo-compounding device, where additional work can be extracted
from the
exhaust stream, than is needed to drive the compressor or forced induction
stage. This
additional work can be compounded mechanically to the drive shaft, extracted
electrically, or
used in some other useful way in the operation of the engine.
[0093]
In some embodiments, an engine can employ the strategies described herein
in
parallel. While independent use of each of these methods is possible, their
combination is
within the scope of this disclosure.
[0094]
Various concepts may be embodied as one or more methods, of which at least
one
example has been provided. The acts performed as part of the method may be
ordered in any
suitable way. Accordingly, embodiments may be constructed in which acts are
performed in
an order different than illustrated, which may include performing some acts
simultaneously,
even though shown as sequential acts in illustrative embodiments Put
differently, it is to be
understood that such features may not necessarily be limited to a particular
order of execution,
but rather, any number of threads, processes, services, servers, and/or the
like that may execute
serially, asynchronously, concurrently, in parallel, simultaneously,
synchronously, and/or the
like in a manner consistent with the disclosure. As such, some of these
features may be mutually
contradictory, in that they cannot be simultaneously present in a single
embodiment. Similarly,
some features are applicable to one aspect of the innovations, and
inapplicable to others.
[0095]
In addition, the disclosure may include other innovations not presently
described.
Applicant reserves all rights in such innovations, including the right to
embodiment such
innovations, file additional applications, continuations, continuations-in-
part, divisionals,
and/or the like thereof. As such, it should be understood that advantages,
embodiments,
examples, functional, features, logical, operational, organizational,
structural, topological,
and/or other aspects of the disclosure are not to be considered limitations on
the disclosure as
defined by the embodiments or limitations on equivalents to the embodiments.
Depending on
the particular desires and/or characteristics of an individual and/or
enterprise user, database
configuration and/or relational model, data type, data transmission and/or
network framework,
syntax structure, and/or the like, various embodiments of the technology
disclosed herein may
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be implemented in a manner that enables a great deal of flexibility and
customization as
described herein.
[0096]
All definitions, as defined and used herein, should be wide' stood to
control over
dictionary definitions, definitions in documents incorporated by reference,
and/or ordinary
meanings of the defined terms.
[0097]
As used herein, in particular embodiments, the terms "about" or
"approximately"
when preceding a numerical value indicates the value plus or minus a range of
10%. Where a
range of values is provided, it is understood that each intervening value, to
the tenth of the unit
of the lower limit unless the context clearly dictates otherwise, between the
upper and lower
limit of that range and any other stated or intervening value in that stated
range is encompassed
within the disclosure. That the upper and lower limits of these smaller ranges
can independently
be included in the smaller ranges is also encompassed within the disclosure,
subject to any
specifically excluded limit in the stated range. Where the stated range
includes one or both of
the limits, ranges excluding either or both of those included limits are also
included in the
disclosure.
[0098]
The phrase "and/or," as used herein in the specification and in the
embodiments,
should be understood to mean "either or both" of the elements so conjoined,
i.e., elements that
are conjunctively present in some cases and disjunctively present in other
cases. Multiple
elements listed with "and/or" should be construed in the same fashion, i.e.,
"one or more" of
the elements so conjoined. Other elements may optionally be present other than
the elements
specifically identified by the "and/or" clause, whether related or unrelated
to those elements
specifically identified. Thus, as a non-limiting example, a reference to "A
and/or B", when
used in conjunction with open-ended language such as "comprising" can refer,
in one
embodiment, to A only (optionally including elements other than B); in another
embodiment,
to B only (optionally including elements other than A); in yet another
embodiment, to both A
and B (optionally including other elements); etc.
[0099]
As used herein in the specification and in the embodiments, "or" should be
understood to have the same meaning as "and/or" as defined above. For example,
when
separating items in a list, "or" or "and/or" shall be interpreted as being
inclusive, i.e., the
inclusion of at least one, but also including more than one, of a number or
list of elements, and,
optionally, additional unlisted items. Only terms clearly indicated to the
contrary, such as "only
one of" or "exactly one of," or, when used in the embodiments, "consisting
of," will refer to
the inclusion of exactly one element of a number or list of elements. In
general, the term "or"
as used herein shall only be interpreted as indicating exclusive alternatives
(i.e. "one or the
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other but not both") when preceded by terms of exclusivity, such as "either,"
"one of," "only
one of," or "exactly one of." "Consisting essentially of," when used in the
embodiments, shall
have its ordinary meaning as used in the field of patent law.
[0100]
As used herein in the specification and in the embodiments, the phrase "at
least
one," in reference to a list of one or more elements, should be understood to
mean at least one
element selected from any one or more of the elements in the list of elements,
but not
necessarily including at least one of each and every element specifically
listed within the list
of elements and not excluding any combinations of elements in the list of
elements. This
definition also allows that elements may optionally be present other than the
elements
specifically identified within the list of elements to which the phrase "at
least one" refers,
whether related or unrelated to those elements specifically identified. Thus,
as a non-limiting
example, "at least one of A and B" (or, equivalently, "at least one of A or
B," or, equivalently
"at least one of A and/or B") can refer, in one embodiment, to at least one,
optionally including
more than one, A, with no B present (and optionally including elements other
than B); in
another embodiment, to at least one, optionally including more than one, B,
with no A present
(and optionally including elements other than A); in yet another embodiment,
to at least one,
optionally including more than one, A, and at least one, optionally including
more than one, B
(and optionally including other elements); etc.
[0101]
As used herein, "fuel" can refer to any material capable of producing an
exothermic
chemical reaction with an intake mixture, regardless of the fuel's cetane
number. This can
include fuels and blends of: naphtha, gasoline, alcohol fuels (including
butanol, propanol,
ethanol, and methanol), gaseous hydrocarbons (including natural gas, methane,
ethane,
propane, butane, hexane, etc.) and alternative fuels such as hydrogen,
ammonia, syngas, CO,
etc.
[0102]
As used herein, "plume" can refer to a mass of fuel spreading from an
injection
point, which may be entraining or mixing with the volume of intake charge as
it progresses
spatially and/or temporally during a fuel injection event.
[0103]
As used herein, "intake charge" refers to a volume of material that enters
a
combustion chamber prior to a combustion event. The intake charge can include
air,
atmospheric air, humid air, air enriched with oxygen, air diluted with exhaust
gas, air diluted
with inert gas, fuel, uncombusted fuel, or any combination thereof.
[0104]
As used herein, "combustion efficiency" can refer to the degree to which
air and
fuel are fully combusted to form the products of complete combustion. As a non-
limiting
example, combustion efficiency can be calculated using lower heating value
(LHV) of the fuel
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(e.g., ethanol, methanol, etc.) and combustion products (e.g., CO2, H20,
etc.), as set forth
below:
LHVproductsmassproducts
71 combustion ¨ 1 LHV mass
fuel fuel
Where:
71 combustion is the combustion efficiency;
LliVproducts is the LHV of the combustion products (MJ/kg);
maSSproducts is the mass of the combustion products (kg);
LHVfue/ is the LHV of the fuel (MJ/kg); and
massfuet is the mass of the fuel (kg).
[0105]
As used herein, "efficiency," "thermal efficiency," or "LHV efficiency" can
refer
to the conversion of fuel energy to mechanical work, calculated as follows:
Work
17 = LHVfueimass fuel
Where:
17 is the efficiency;
Work is the amount of mechanical work achieved (J), which can be the indicated
work
calculated from the pressure in the engine cylinder, or the brake work, where
the work is
measured at the point of the rotating shaft going from the engine into a
transmission or
generator (i.e., the "brake thermal efficiency);
LHVfuei is the LHV of the fuel (J/kg); and
massfuet is the mass of the fuel (kg).
[0106]
As used herein, a numerical definition of a "crank angle" or an "engine
crank angle"
should be understood as the crank angle relative to a fixed point in the
engine cycle (as
described below in Table 1 for the case of a four-stroke engine). In other
words, in a four-
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stroke engine, the engine crank angle is 00 (or 7200) when the piston is in
the TDC position
between the exhaust stroke and the intake stroke. The engine crank angle is
3600 when the
piston is in the TDC position between the compression stroke and the expansion
stroke. The
engine crank angle is 540 when the piston is in the BDC position between the
expansion stroke
and the exhaust stroke. The engine crank angle is 180 when the piston is in
the BDC position
between the intake stroke and the compression stroke. Negative numbers can
also be used to
describe the crank angle relative to the TDC position between the exhaust
stroke and the intake
stroke. In other words, 540' can also be described as -180', 360' can also be
described as -
360 , and 180 can also be described as -540 In a two-stroke engine, an
engine cycle is 360
in duration, described in table 2 below. A six-stroke engine would likewise
have 1080 total
degrees.
Table 1. Crank Angle Descriptions for a Four Stroke Engine
Crank Angle (Degrees) Piston Position Stroke Description
360 TDC Between compression
stroke
and expansion stroke. In some
(-360)
literature, this crank angle is
referred to as "TDC
Combustion"
Between 360 and 540 Transitioning from Expansion stroke
TDC to BDC
(Between -360 and -180)
540 BDC Between expansion
stroke and
exhaust stroke
(-180)
Between 540 and 720 Transitioning from Exhaust stroke
BDC to TDC
(Between -180 and 0)
0 or 720 TDC Between exhaust stroke
and
intake stroke. In some literature,
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this crank angle is referred to as
"TDC gas exchange"
Between 0 and 180 Transitioning from Intake stroke
TDC to BDC
(Between -720 and -540)
180 BDC Between intake stroke
and
compression stroke
(-540)
Between 180 and 360 Transitioning from Compression stroke
BDC to TDC
(Between -540 and -360)
360 TDC Between compression
stroke
and expansion stroke. In some
(-360)
literature, this crank angle is
referred to as
"TDC
Combustion"
Table 2: Crank angle convention for two-stroke engines
Crank Angle (Degrees) Piston Position Stroke Description
0 TDC Between compression
stroke
and expansion stroke. In some
(360)
literature, this crank angle is
referred to as "TDC
Combustion"
Between 1-180 Transitioning from Expansion stroke
TDC to BDC
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Between ¨90-270 Transition past BDC Exhaust,
scavenging, and intake
from expansion to
compression
Between 180 and 360 Transitioning from Compression stroke
BDC to TDC
(Between -180 and 0)
[0107]
In some embodiments, the term "immediately prior to ignition" or "just
prior to
ignition" can refer to a temporal point, at which the engine crank angle is
about 3000, about
305 , about 310 , about 315 , about 320 , about 325 , about 330 , about 335 ,
about 340 ,
about 345 , about 350 , about 355 , about 360 , about 365 , about 370 , about
375 , or about
380 , inclusive of all values and ranges therebetween.
[0108]
In some embodiments, the term "immediately prior to ignition" or "just
prior to
ignition" can refer to a temporal point of approximately 50 ms, approximately
40 ms,
approximately 30 ms, approximately 20 ms, approximately 10 ms, approximately 5
ms,
approximately 2 ms, or approximately 1 ms prior to ignition, inclusive of all
values and ranges
therebetween.
[0109]
In some embodiments, the term "immediately prior to ignition" or "just
prior to
ignition" can refer to a temporal point preceding the time at which 5% of the
fuel exothermi city
is observed to have happened. In other words, the fuel can be considered to
have ignited when
a measurable deviation in pressure could be detected to indicate exothermic
fuel oxidation is
occurring.
[0110]
In some embodiments, the term "immediately prior to ignition- or "just
prior to
ignition" can refer to a temporal point about 1 crank angle degree, about 2
crank angle degrees,
about 3 crank angle degrees, about 4 crank angle degrees, about 5 crank angle
degrees, about
6 crank angle degrees, about 7 crank angle degrees, about S crank angle
degrees, about 9 crank
angle degrees, about 10 crank angle degrees, about 11 crank angle degrees,
about 12 crank
angle degrees, about 13 crank angle degrees, about 14 crank angle degrees,
about 15 crank
angle degrees, about 16 crank angle degrees, about 17 crank angle degrees,
about 18 crank
angle degrees, about 19 crank angle degrees, or about 20 crank angle degrees
prior to ignition,
inclusive of all values and ranges therebetween.
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[0111]
In some embodiments, the term "immediately prior to ignition" or "just
prior to
ignition" can refer to a temporal point about 50 ms, about 40 ms, about 30 ms,
about 20 ms,
about 10 ms, about 5 ins, about 2 ins, or about 1 ins prim to ignition,
inclusive of all values and
ranges therebetween.
[0112]
In some embodiments, the term "immediately prior to fuel injection" or
"just prior
to fuel injection" can refer to a temporal point about 1 crank angle degree,
about 2 crank angle
degrees, about 3 crank angle degrees, about 4 crank angle degrees, about 5
crank angle degrees,
about 6 crank angle degrees, about 7 crank angle degrees, about 8 crank angle
degrees, about
9 crank angle degrees, about 10 crank angle degrees, about 11 crank angle
degrees, about 12
crank angle degrees, about 13 crank angle degrees, about 14 crank angle
degrees, about 15
crank angle degrees, about 16 crank angle degrees, about 17 crank angle
degrees, about 18
crank angle degrees, about 19 crank angle degrees, or about 20 crank angle
degrees prior to
fuel injection, inclusive of all values and ranges therebetween.
[0113]
In some embodiments, the term "immediately prior to fuel injection" or
"just prior
to fuel injection" can refer to a temporal point about 50 ms, about 40 ms,
about 30 ms, about
20 ms, about 10 ms, about 5 ms, about 2 ms, or about 1 ms prior to fuel
injection, inclusive of
all values and ranges therebetween.
[0114]
In some embodiments, the term "valve closing" (e.g., "intake valve closing"
or
"exhaust valve closing") can refer to a temporal point, wherein the valve
becomes fully seated
(i.e., 0 mm valve lift). In some embodiments, the term "valve opening" (e.g.,
"intake valve
opening" or "exhaust valve opening") can refer to a temporal point, wherein
the valve becomes
unseated (i.e., >0 mm lift).
[0115]
In the embodiments, as well as in the specification above, all transitional
phrases
such as "comprising," "including," "carrying," "having," "containing,"
"involving," "holding,"
"composed of," and the like are to be understood to be open-ended, i.e., to
mean including but
not limited to. Only the transitional phrases "consisting of' and "consisting
essentially or shall
be closed or semi-closed transitional phrases, respectively, as set forth in
the United States
Patent Office Manual of Patent Examining Procedures, Section 2111.03.
[0116]
In some embodiments, the novel, high-temperature mixing-controlled strategy
described herein can be implemented in an opposed piston engine. This could
include 2 or more
pistons configured to compress an inducted charge, the engine potentially
having no cylinder
head. This could be a two-four-or other number of stroke design.
[0117]
While specific embodiments of the present disclosure have been outlined
above,
many alternatives, modifications, and variations will be apparent to those
skilled in the art.
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Accordingly, the embodiments set forth herein are intended to be illustrative,
not limiting.
Various changes may be made without departing from the spirit and scope of the
disclosure.
Where methods and steps described above indicate certain events occurring in a
certain order,
those of ordinary skill in the art having the benefit of this disclosure would
recognize that the
ordering of certain steps may be modified and such modification are in
accordance with the
variations of the invention Additionally, certain of the steps may be
performed concurrently
in a parallel process when possible, as well as performed sequentially as
described above. The
embodiments have been particularly shown and described, but it will be
understood that various
changes in form and details may be made
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Representative Drawing