Note: Descriptions are shown in the official language in which they were submitted.
METHOD AND SYSTEM FOR CONTROLLING A TURBOCHARGED
TWO STROKE ENGINE BASED ON BOOST ERROR
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. Application No.
16/692,470, filed November 22, 2019, which claims priority to U.S. Application
No. of
62/776,611, filed December 7, 2018 and U.S. Application No. 62/960,414, filed
January
13, 2020. This application incorporates the disclosures of U.S. Application
No.
16/691,995 filed November 22, 2019, U.S. Application No. 16/696,198 filed
November
26, 2019, U.S. Application No. 16/691,097 filed November 21, 2019, U.S.
Application
No. 16/692,336 filed November 22, 2019, U.S. Application No. 16/692,470 filed
November 22, 2019, U.S. Application No. 16/692,628 filed November 22, 2019,
U.S.
Application No. 16/692,724 filed November 22, 2019, U.S. Application No.
16/692,795
filed November 22, 2019, and U.S. Provisional Application No. 62/690,388 filed
on
January 13, 2020. The entire disclosures of the above applications are
incorporated
herein by reference.
FIELD
[0002] The present disclosure relates to a vehicle engine and, more
particularly,
to a method of operating the engine and turbocharger based on boost error.
BACKGROUND
[0003] This section provides background information related to the
present
disclosure which is not necessarily prior art.
1
Date Recue/Date Received 2022-01-07
[0004]
A vehicle, such as a snowmobile, generally includes an engine assembly.
The engine assembly is operated with the use of fuel to generate power to
drive the
vehicle. The power to drive a snowmobile is generally generated by a
combustion
engine that drives pistons and a connected crankshaft. Two-stroke snowmobile
engines
are highly tuned, and high specific power output engines that operate under a
wide
variety of conditions.
[0005]
Vehicle manufacturers are continually seeking ways to improve the power
output for engines. Turbochargers have been used together with two-stroke
engines to
provide increased power output. However, improving the packaging and
performance
of a turbocharged two-stroke engine is desirable.
SUMMARY
[0006]
This section provides a general summary of the disclosures, and is
not a comprehensive disclosure of its full scope or all of its features. The
present
disclosure provides a system of control based on boost error.
[0007]
In a first aspect of the disclosure, a method of controlling a
wastegate comprises determining a boost pressure target, measuring a boost
pressure,
determining a boost pressure error from the measured boost pressure and the
boost
pressure target, determining a wastegate position change based on boost
pressure
error, and changing the wastegate position corresponding to the wastegate
position
change.
[0008]
In another aspect of the disclosure, a system includes a boost
pressure sensor generating a boost pressure signal and a controller programmed
to
2
Date Recue/Date Received 2022-01-07
determine a boost pressure error from the boost pressure signal and a boost
pressure
target, determine a wastegate position change based on boost pressure error. A
wastegate actuator is coupled to the controller changing the wastegate
position based
on the wastegate position change.
[0009] Further areas of applicability will become apparent from the
description
provided herein. The description and specific examples in this summary are
intended for
purposes of illustration only and are not intended to limit the scope of the
present
disclosure.
DRAWINGS
[0010] Figure 1 is a perspective view of a snowmobile.
[0011] Figure 2 is an exploded view of the snowmobile of FIG 1.
[0012] Figures 2A and 2B are enlarged exploded views of FIG 2.
[0013] Figure 3 is a block diagram of the engine of Figure 2.
[0014] Figure 4 is an exploded view of the engine of FIG 3.
[0015] Figure 5A is a perspective view of a turbocharger according to the
present
disclosure.
[0016] Figure 5B is a side view of the turbocharger Figure 5A.
[0017] Figure 5C is a cutaway view of the turbine housing of the
turbocharger of
Figure 5A.
[0018] Figure 5D is a partial cross-sectional view of the turbine housing
of the
turbocharger of Figure 5A.
[0019] Figure 5E is a cutaway view of the turbocharger having the
diverter valve
in a position closing off the first scroll.
3
Date Recue/Date Received 2022-01-07
[0020] Figure 5F is a partial cutaway view of the turbocharger having the
diverter
valve in a neutral position.
[0021] Figure 5G is a partial cutaway view of the turbocharger having the
diverter
valve in a position closing off the second scroll.
[0022] Figure 5H is a partial cutaway view of an alternate valve for
controlling
flow to the scrolls in a partially open position.
[0023] Figure 51 is a partial cutaway view of the valve in Figure 5H in a
closed
position.
[0024] Figure 5J is a partial cutaway view of another alternate valve for
controlling flow to one of the scrolls in a closed position.
[0025] Figure 5K is a partial cutaway view of the valve in Figure 5J in a
partially
open position.
[0026] Figure 6A is a cross-sectional view of an exhaust gas bypass
valve.
[0027] Figure 6B is the exhaust bypass valve of Figure 6A in a first open
position.
[0028] Figure 6C is the exhaust bypass valve of Figure 6A in a second
open
position.
[0029] Figure 6D is the exhaust bypass valve of Figure 6A in a third open
position.
[0030] Figure 6E is the exhaust bypass valve of Figure 6A in a fully open
position.
[0031] Figure 6F is a perspective view of the exhaust bypass valve with
an
actuator arm.
4
Date Recue/Date Received 2022-01-07
[0032] Figure 6G is an end view of the exhaust bypass valve in the
position
illustrated in Figure 6E.
[0033] Figure 6H is a block diagrammatic view of a system for operating
the
exhaust bypass valve of Figure 6A.
[0034] Figure 61 is a perspective view of an exhaust bypass valve and
diverter
valve controlled by a common actuator.
[0035] Figure 6J is a perspective view of a wastegate actuator according
to an
example of the present disclosure.
[0036] Figure 6K is a block diagrammatic view of a wastegate actuator and
a
coupler.
[0037] Figure 6L is another example of a coupler for a wastegate.
[0038] Figure 6M is a perspective view of a method for joining a coupler.
[0039] Figure 6N is a perspective view of a turbocharger system with
exhaust
bypass valve coupled via flexible shaft to an electronic actuator.
[0040] Figure 60 is a perspective view of a rotating member of the
coupler Figure
6N.
[0041] Figure 6P is a perspective view of a flexible coupler for a
wastegate
coupled to a wastegate actuator coupled to a bracket formed with the
turbocharger.
[0042] Figure 6Q is a perspective view of a clamp for clamping a
wastegate
actuator and wastegate to a tuned pipe.
[0043] Figure 7A is a schematic view of a system for bypassing exhaust
gas.
[0044] Figure 7B is a schematic view of a second example for bypassing
exhaust
gas.
Date Recue/Date Received 2022-01-07
[0045] Figure 7C is a schematic view of a third example of bypassing
exhaust
gas.
[0046] Figure 7D is a schematic view of a fourth example of bypassing
exhaust
gas.
[0047] Figure 7E is a diagrammatic representation of an engine system
including
exhaust bypass for increasing the stability of a two-stroke engine.
[0048] Figure 7F is a diagrammatic representation of an engine assembly
comprising a second example of increasing the stability of a two stoke engine.
[0049] Figure 7G is a diagrammatic representation of an engine assembly
having
a third example of an exhaust bypass valve for increasing the stability of a
two-stroke
engine alternate positions of the exhaust bypass valve are illuminated.
[0050] Figure 7H is a diagrammatic representation of a control valve
within a
stinger of the exhaust system of a normally aspirated two-stroke engine
assembly.
[0051] Figure 71 is a diagrammatic representation of a control valve
within a
silencer.
[0052] Figure 7J is a diagrammatic representation of a control valve
within a sub-
chamber of a silencer.
[0053] Figure 7K is a schematic view of another example of bypassing
exhaust
gas using a silencer and supplemental silencer with a common wall.
[0054] Figure 7L is a schematic view of two part muffler with a common
wall
therebetween having two inputs and a single exhaust pipe receiving exhaust
gasses
from both parts of the muffler.
6
Date Recue/Date Received 2022-01-07
[0055] Figure 7M is a schematic view of a pipe from a turbocharger and
pipe from
a wastegate joined at a Y-joint before the silencer.
[0056] Figure 7N is a schematic view of the pipe coupled to a flange
prior to
entering the silencer wherein the flange and joint may all be formed as one
component.
[0057] Figure 70 is a schematic view of the engine assembly, the tuned
pipe and
the turbocharger wherein the effective area of cross-sectional flow of the
wastegate or
exhaust bypass valve is greater than the cross-section flow area of the
stinger.
[0058] Figure 8A is a schematic view of a system for bypassing the
compressor
of a turbocharged engine to provide airflow to the engine.
[0059] Figure 8B is a rear side of the boost box of Figure 8A.
[0060] Figure 8C is a left side view of the boost box of Figure 8A.
[0061] Figure 8D is a front side view of the boost box of Figure 8A.
[0062] Figure 8E is a right side view of the boost box of Figure 8A.
[0063] Figure 8F is an enlarged view of the one-way valve of Figure 8A.
[0064] Figure 8G is a side view of an engine compartment having the boost
box
oriented so that the one-way valve is located rearwardly.
[0065] Figure 8H is a side view of a boost box coupled to a duct.
[0066] Figure 81 is a side view of the boost box coupled to a channel
integrally
formed with a fuel tank.
[0067] Figure 9A is a block diagrammatic view of a system for controlling
an
exhaust bypass valve.
[0068] Figure 9B is a flowchart of a method for controlling the exhaust
gas
bypass valve.
7
Date Recue/Date Received 2022-01-07
[0069] Figure 9C is a plot of boost error versus time for a plurality of
signals used
for updating the exhaust gas bypass valve position.
[0070] Figure 9D is a plot of the calculation multiplier versus boost
error.
[0071] Figure 9E is a graph illustrating the absolute pressure and
changes over
various altitudes.
[0072] Figure 9F is a flowchart of a method for controlling an exhaust
gas bypass
valve to increase power or stability of a two-stroke engine.
[0073] Figure 9G is a block diagrammatic view of a first example of the
exhaust
gas bypass valve position control module.
[0074] Figure 9H is a flowchart of a method for operating the exhaust gas
bypass
valve in response to an idle and acceleration event.
[0075] Figure 10A is a side view of a rotor of a turbocharger.
[0076] Figure 10B is an end view of the rotor of Figure 10A.
[0077] Figure 10C is a diagrammatic representation of the exducer area.
[0078] Figure 10D is a plot of the ratio of exhaust gas bypass valve or
bypass
valve area to exducer area for known four stroke engines, two stroke engines
and the
present example.
[0079] Figure 11A is a method for controlling the exhaust valve of the
engine.
[0080] Figure 11B is a diagrammatic representation of the gains for the
wastegate position.
[0081] Figure 11C is a flowchart of a method for changing the wastegate
position.
[0082] Figure 12A is a block diagrammatic view of a system for allowing
the user
to select a boost mode.
8
Date Recue/Date Received 2022-01-07
[0083] Figure 12B is a flowchart of a method for allowing a user to
select a boost
mode.
[0084] Figure 12C is a flowchart of the control strategy of Figure 12B.
[0085] Figure 13A is a flowchart of a method for preventing overboost in
an
engine.
[0086] Figure 13B is a flowchart of a method for preventing
overtemperature in
an engine.
[0087] Figure 14A is a flowchart of a method for controlling the
wastegate based
upon deceleration.
[0088] Figure 14B is a signal diagram that shows the wastegate opening
slightly
based upon an overboost condition.
[0089] Figure 14C is a signal diagram that shows driving the wastegate
more fully
opened based upon deceleration.
[0090] Figure 15A and 15B are flowcharts of a method for controlling the
engine
in an acceleration mode.
[0091] Figure 15C is a signal diagram showing the engine when controlled
for an
acceleration mode.
[0092] Figure 16A is a front view of a connecting rod according to the
present
disclosure.
[0093] Figure 16B is a cross-sectional view of the connecting rod.
[0094] Figure 16C is a force diagram of connecting rods with and without
the
inertia reducing holes.
9
Date Recue/Date Received 2022-01-07
[0095] Figure 16D is an inertia diagram of the connecting rods with and
without
the inertia reducing holes.
[0096] Figure 17 is a perspective view of roller bearings according to
the present
disclosure,
[0097] Figure 18 is a block diagrammatic view of a system for controlling
the
engine in further detail relative to a sensor diagnostic mode, a wastegate
initialization
mode, an exhaust valve controller and fuel adjustment module.
[0098] Figure 19 is a flowchart of a method for controlling an engine
based upon
the absolute air box pressure.
[0099] Figure 20 is a method for checking the range of a wastegate upon
startup.
[00100] Figure 21 is a flowchart of a method for monitoring the current of the
wastegate upon startup.
[00101] Figure 22 is a flowchart of a method of controlling fueling and
ignition
based upon the wastegate position.
[00102] Figure 23 is a signal diagram of the engine speed uncorrected and
corrected relative to the wastegate position and the throttle position and the
boost
pressure.
[00103] Figure 24 is a flowchart of a method for determining the difference
between barometric pressure and the boost sensor.
[00104] Figure 25 is a diagrammatic view of a diagnostic threshold for use
with the
method of Figure 24.
Date Recue/Date Received 2022-01-07
DETAILED DESCRIPTION
[00105] Examples will now be described more fully with reference to the
accompanying drawings. Although the following description includes several
examples
of a snowmobile application, it is understood that the features herein may be
applied to
any appropriate vehicle, such as motorcycles, all-terrain vehicles, utility
vehicles,
moped, scooters, etc. The examples disclosed below are not intended to be
exhaustive
or to limit the disclosure to the precise forms disclosed in the following
detailed
description. Rather, the examples are chosen and described so that others
skilled in the
art may utilize their teachings. The signals set forth below refer to
electromagnetic
signals that communicate data.
[00106] Referring now to Figures 1 and 2, one example of an exemplary
snowmobile 10 is shown. Snowmobile 10 includes a chassis 12, an endless belt
assembly 14, and a pair of front skis 20. Snowmobile 10 also includes a front-
end 16
and a rear-end 18.
[00107] The snowmobile 10 also includes a seat assembly 22 that is coupled to
the chassis assembly 12. A front suspension assembly 24 is also coupled to the
chassis
assembly 12. The front suspension assembly 24 may include handlebars 26 for
steering, shock absorbers 28 and the skis 20. A rear suspension assembly 30 is
also
coupled to the chassis assembly 12. The rear suspension assembly 30 may be
used to
support the endless belt 14 for propelling the vehicle. An electrical console
assembly 34
is also coupled to the chassis assembly 12. The electrical console assembly 34
may
include various components for displaying engine conditions (i.e., gauges) and
for
electrically controlling the snowmobile 10.
11
Date Recue/Date Received 2022-01-07
[00108] The snowmobile 10 also includes an engine assembly 40. The engine
assembly 40 is coupled to an intake assembly 42 and an exhaust assembly 44.
The
intake assembly 42 is used for providing fuel and air into the engine assembly
40 for the
combustion process. Exhaust gas leaves the engine assembly 40 through the
exhaust
assembly 44. The exhaust assembly 44 includes the exhaust manifold 45 and
tuned
pipe 47. An oil tank assembly 46 is used for providing oil to the engine for
lubrication
where it is mixed directly with fuel. In other systems oil and fuel may be
mixed in the
intake assembly. A drivetrain assembly 48 is used for converting the rotating
crankshaft
assembly from the engine assembly 40 into a potential force to use the endless
belt 14
and thus the snowmobile 10. The engine assembly 40 is also coupled to a
cooling
assembly 50.
[00109] The chassis assembly 12 may also include a bumper assembly 60, a hood
assembly 62 and a nose pan assembly 64. The hood assembly 62 is movable to
allow
access to the engine assembly 40 and its associated components.
[00110] Referring now to Figures 3 and 4, the engine assembly 40 is
illustrated in
further detail. The engine assembly 40 is a two-stroke engine that includes
the exhaust
assembly 44 that includes an exhaust manifold 45, tuned pipe 47, an exhaust
valve 49,
an exhaust port actuator 49A and exhaust silencer 710. The exhaust valve 49
may be
electronically controlled to achieve various states of opening and closing.
[00111] The engine assembly 40 may include spark plugs 70 which are coupled to
a one-piece cylinder head cover 72. The cylinder head cover 72 is coupled to
the
cylinder 74 with twelve bolts which is used for housing the pistons 76 to form
a
12
Date Recue/Date Received 2022-01-07
combustion chamber 78 therein. The cylinder 74 is mounted to the engine upper
crankcase 80.
[00112] The fuel and ignition system 82 that forms part of the engine assembly
40,
includes fuel lines 84 and fuel injectors 86 and the controlloer to determine
fuuel
quantities and ignition timing. The fuel lines 84 provide fuel to the fuel
injectors 86 which
inject fuel, in this case, into a port in the cylinder adjacent to the pistons
76. In other
cases, an injection may take place adjacent to the piston, into a boost box
(detailed
below) or into the throttle body. An intake manifold 88 is coupled to the
engine upper
crankcase 80. The intake manifold 88 is in fluidic communication with the
throttle body
90. Air for the combustion processes is admitted into the engine through the
throttle
body 90 which may be controlled directly through the use of an accelerator
pedal or
hand operated lever or switch. A throttle position sensor 92 is coupled to the
throttle to
provide a throttle position signal corresponding to the position of the
throttle plate 94 to
an engine controller discussed further herein.
[00113] The engine upper crankcase 80 is coupled to lower crankcase 100 and
forms a cavity for housing the crankshaft 102. The crankshaft 102 has
connecting rods
104 which are ultimately coupled to the pistons 76. The movement of the
pistons 76
within the combustion chamber 78 causes a rotational movement at the
crankshaft 102
by way of the connecting rods 104. The crankcase may have openings or vents
106
therethrough.
[00114] The system is lubricated using oil lines 108 which are coupled to the
oil
injectors 110 and an oil pump 112.
13
Date Recue/Date Received 2022-01-07
[00115] The crankshaft 102 is coupled to a generator flywheel 118 and having a
stator 120 therein. The flywheel 118 has crankshaft position sensors 122 that
aid in
determining the positioning of the crankshaft 102. The crankshaft position
sensors 122
are aligned with the teeth 124 and are used when starting the engine, as well
as being
used to time the operation of the injection of fuel during the combustion
process. A
stator cover 126 covers the stator 120 and flywheel 118.
[00116] Discussed below are various features of the engine assembly 40 used in
the snowmobile 10. Each of the features relate to the noted section headings
set forth
below. It should be noted that each of these features can be employed either
individually or in any combination with the engine assembly 40. Moreover, the
features
discussed below will utilize the reference numerals identified above, when
appropriate,
or other corresponding reference numerals as needed. Again, as noted above,
while the
engine assembly 40 is a two-stroke engine that can be used with the snowmobile
10,
the engine assembly 40 can be used with any appropriate vehicles and the
features
discussed below may be applied to four-stroke engine assemblies as well.
[00117] The engine assembly 40 also includes an exhaust manifold 45 that
directs
the exhaust gases from the engine. The exhaust manifold 45 is in fluid
communication
with a tuned pipe 47. The tuned pipe 47 is specifically shaped to improve the
performance and provide the desired feedback to the engine assembly 40. The
tuned
pipe 47 is in communication with a stinger 134. The tuned pipe 47 has a bypass
pipe
136 coupled thereto. The bypass pipe 136 has an exhaust gas bypass valve 138
used
for bypassing some or all of the exhaust gases from being directed to a
turbocharger
140. Details of the turbocharger 140 are set forth in the following Figures.
14
Date Recue/Date Received 2022-01-07
[00118] Referring now to Figures 5A-5G, the turbocharger 140 includes a
turbine
portion 510 and a pump or compressor portion 512. The turbine portion 510 and
the
compressor portion 512 have a common shaft 521 that extends there between.
That is,
the rotational movement within the turbine portion 510 caused from the exhaust
gases
rotate a turbine wheel 520 which in turn rotates the shaft 521 which, in turn,
rotates a
compressor wheel 519. The compressor portion 512 includes an inlet 514 and an
outlet
516. Movement of the compressor wheel 519 causes inlet air from the inlet 514
to be
pressurized and output through the outlet 516 of the housing 518.
[00119] The turbine portion 510 includes a turbine wheel 520 with housing 522.
The housing 522 includes a turbine inlet 524 and a turbine outlet 526. The
inlet 524
receives exhaust gas through the tuned pipe 47 and the stinger 134 as
illustrated
above. The exhaust gases enter the inlet 524 and are divided between a first
scroll 528
and a second scroll 530. Of course, more than two scrolls may be implemented
in a
system. The scrolls 528, 530 may also be referred to as a volute. Essentially
the first
scroll 528 and the second scroll 530 start off with a wide cross-sectional
area and taper
to a smaller cross-sectional area near the turbine wheel. The reduction in
cross-
sectional area increases the velocity of the exhaust gases which in turn
increases the
speed of the turbine wheel 520. Ultimately, the rotation of the turbine wheel
520 turns
the compressor wheel 519 within the compressor portion 512 by way of a common
shaft
521. The size of the first scroll 528 and the second scroll 530 may be
different. The
overall area to radius (A/R) ratio of the scrolls may be different. The first
scroll 528 has
a first end 528A and a second end 528B and the second scroll has a second
first end
530A and a second end 530B. The first ends 528A, 530A are adjacent to the
turbine
Date Recue/Date Received 2022-01-07
inlet 524. The second ends 528B, 530B are adjacent to the turbine wheel 520
within
the housing 522. The volume of the first scroll 528 and second scroll 530 may
be
different. The cross-sectional opening adjacent to the turbine wheel 520 may
be
different between the scrolls.
[00120] The first scroll 528 and the second scroll 530 are separated by a
separation wall 532. The separation wall 532 separates the first scroll 528
from the
second scroll 530. The separation wall 532 may extend from the first end 528A
of the
first scroll 528 and the first end 530A of the second scroll 530 to the second
end 528B,
530B of the respective scrolls.
[00121] The turbine portion 510 includes an exhaust gas diverter valve 540
mounted adjacent to the separation wall 532. The exhaust gas diverter valve
540 is
used to selectively partially or fully close off either the first scroll 528
or the second scroll
530. A valve seat 542A is located adjacent to the first scroll 528. A second
valve seat
542B is located adjacent to the second scroll 530. Either one of the valve
seats 542A,
542B receive the exhaust gas diverter valve 540 when the exhaust gas diverter
valve
540 is in a completely closed position. The valve seats 542A, 542B may be
recesses or
grooves that are formed within the housing 522. The valve seats 542A, 542B
form a
surface that receives an edge 541 of the exhaust gas diverter valve 540 so
that when
exhaust gases push the exhaust gas diverter valve 540 into the scroll outer
wall, the
valve seats 542A, 542B provide a counter force. The edge 541 is the end of the
valve
540 opposite a pivot pin 544. The valve seats 542A, 542B may be
circumferentially
formed within each of the first scroll 528 and the second scroll 530. The seal
between
16
Date Recue/Date Received 2022-01-07
the valve 540 may be on the edge 541 or on the surface of the valve 540 on
each side
of the edges 541.
[00122] The pivot pin 544 which extends across the turbine inlet 524 to
selectively
separate or close off the first scroll 528 or the second scroll 530. A partial
closing of
either the first scroll 528 or the second scroll 530 may also be performed by
the exhaust
gas diverter valve 540. The exhaust gas diverter valve 540 pivots about the
pivot pin
544. As is best shown in Figure 5B, an actuator 548 such as a motor or a
hydraulic
actuator may be coupled to the exhaust gas diverter valve 540. Other types of
actuators
include pneumatic actuator. The actuator 548 moves the exhaust gas diverter
valve to
the desired position in response to various inputs as will be described in
more detail
below. That is, there may be conditions where both scrolls may be fully
opened, or one
or the other scroll may be opened, at least partially. The opening and closing
of the
valve may be used to control the pressure in the tuned pipe. Further, one
scroll may be
partially closed using the exhaust gas diverter valve 540 while one scroll may
be fully
open as indicated by the dotted lines. That is, in Figure 5E the scroll 530 is
completely
closed by the edge 541 of the exhaust gas diverter valve 540 being received
within the
valve seat 542B. In Figure 5F the exhaust gas diverter valve 540 is in a
middle or
neutral position in which the first scroll 528 and the second scroll 530 are
fully opened.
That is, the valve is in a fully opened position and is coincident to or
parallel with the
separation wall 532. In Figure 5G the edge 541 of the exhaust gas diverter
valve 540 is
received within and rests against the valve seat 542A to fully close the first
scroll 528.
[00123] Referring now to Figures 5H and 51, a butterfly type valve 550 may be
used in place of the diverter valve 540. The butterfly valve 550 pivots about
pivot pin
17
Date Recue/Date Received 2022-01-07
544. The edge 552 of the valve 550 rests against the valve seat 556 in a
closed
position (Figure 51). The closure may result in a seal or a near closure if a
protrusion
553A is on the edge 552 of valve or bump 553B on the seat 556. A dotted
protrusion
553B is shown on the edges 552 and valve seat 556. The valve 550 may be in
communication with an actuator and motor (or hydraulic actuator or a pneumatic
actuator) to move the valve 550 into the desired position. In this manner the
valve 550
is more balanced with respect to exhaust gas acting on the valve blade than
the diverter
valve 540.
[00124] Referring now to Figures 5J and 5K, alternate configuration for a
butterfly
type valve 560 may be used in place of the diverter valves 540 and 550. The
butterfly
valve 560 is disposed within one of the scrolls. In this example scroll 530
has the first
butterfly type valve 560. The butterfly valve 560 pivots about pivot pin 564.
The edge
562 of the valve 560 rests against the valve seat 566 in a closed position
(Figure 5J).
The valve 560 may be in communication with an actuator and motor (or hydraulic
actuator or a pneumatic actuator) to move the valve 560 into the desired
position. In
this manner, the valve 560 is more balanced with respect to exhaust gas acting
on the
valve blade than the diverter valve 540.
[00125] In any of the examples in Figures 5A-5K, the valve 550 may also be
made
oval. The closed position may be less than 90 degrees. The closure may not be
air tight
intentionally. In addition, any of Figures 5A-5K may have the protrusions 553A
and/or
553B.
[00126] Referring now to Figures 6A-6F, an exhaust gas bypass valve 138 is set
forth. By way of example, for a turbocharged engine the exhaust gas bypass
valve 138
18
Date Recue/Date Received 2022-01-07
may be implemented in a wastegate or diverter valve. Some implementations do
not
have a turbocharger but an exhaust bypass valve or wastegate is used to direct
axhaust
gasses from the tuned pipe. The exhaust gas bypass valve 138 may be configured
in
the bypass pipe 136 that connects the exhaust gas from the exhaust manifold 45
and
the tuned pipe 47 to an exhaust pipe 142 coupled to the outlet of the turbine
portion of
the turbocharger 140. Of course, as detailed below, the exhaust gas bypass
valve 138
may be used in various positions within the exhaust assembly 44.
[00127] The exhaust gas bypass valve 138 has an exhaust gas bypass valve
housing 610. The exhaust gas bypass valve housing 610 may have a first flange
612A
and a second flange 612B. The flanges 612A, 612B are used for coupling the
exhaust
gas bypass valve to the respective portions of the bypass pipe 136A, 136B. Of
course,
direct welding to the tuned pipe or bypass piping may be performed. The
housing 610
has an outer wall 611 that is generally cylindrical in shape and has a
longitudinal axis
613 which also corresponds to the general direction of flow through the
exhaust gas
bypass valve housing 610. The outer wall 611 has a thickness Ti.
[00128] The housing 610 includes a valve plate or valve member 614 that
rotates
about a rotation axis 616. The rotation axis 616 coincides with an axle 618
that is
coupled to the housing 610 so that the valve member 614 rotates thereabout in
a
direction illustrated by the arrow 620. The valve member 614 is balanced to
minimize
the operating torque required to open/close the valve member 614. The
butterfly
arrangement has exhaust gas working on both sides of the valve member 614,
which
effectively causes the forces to counteract and 'cancel each other that
results in a
significantly reduced operating torque. Consequently, the valve member 614 may
be
19
Date Recue/Date Received 2022-01-07
sized as wastegate as big as necessary without significantly increasing the
operating
torque to actuate it. Advantageously a smaller (and likely less expensive)
actuator may
be utilized.
[00129] The housing 610 may include a first valve seat 622 and a second valve
seat 624. The seats 622 and 624 are integrally formed with the housing. As is
illustrated, the valve seats 622 and 624 are thicker portions of the housing.
The valve
seats 622, 624 may have a thickness T2 greater than Ti. Of course, casting
thicknesses may change such as by providing pockets of reduced thickness for
weight
saving purposes. The valves seats 622, 624 are circumferential about or within
the
housing 610. However, each of the valve seats 622 and 624 extends about half
way
around the interior of the housing to accommodate the axle 618.
[00130] The valve seats 622, 624 have opposing surfaces 626, 628 that have a
planar surface that are parallel to each other. The surfaces 626, 628 contact
opposite
sides of the valve member 614 in the closed position. This allows the valve
member
614 to rest against each valve seat 622, 624 to provide a seal in the closed
position.
The exhaust gas bypass valve 138 and the valve member 614 therein move in
response to movement of an actuator 630. The actuator 630 rotates the valve
member
614 about the axis 616 to provide the valve member 614 in an open and a closed
position. Of course, various positions between open and closed are available
by
positioning the actuator 630. As will be further described below, the actuator
630 may
actuate the valve member 614, exhaust gas diverter valve 540 and valves 550,
560 as
described above. As mention above the surface area of the valve member 614 is
the
Date Recue/Date Received 2022-01-07
same above and below the axis 616 so that the operating toque is minimized due
to the
exhaust gas load being distributed evenly on both sides of the axis 616.
[00131] The effective cross-sectional area of opening, passage or port P1
available to the exhaust gasses flowing through the interior of the exhaust
gas bypass
valve is limited by the distance T2 and the valve member 614 and axle 618.
After
experimentation, it was found that the effective cross-sectional area of the
exhaust gas
bypass valve 138 may be formed as a function of an exducer of the turbine
wheel 520
as is described in greater detail below.
[00132] To vary the effective area, the valve member 614 of the exhaust gas
bypass valve 138 has different angles al- a4 illustrated in Figures 6B to 6E
respectively.
The angles al- a4 progressively increase. The angular opening corresponds
directly
with the effective area of the exhaust gas bypass valve 138. The angular
opening of
the exhaust gas bypass valve 138 may be controlled in various ways or in
response to
various conditions. Although specific angles are illustrated, the exhaust gas
bypass
valve 138 is infinitely variable between the fully closed position of Figure
6A and the
fully open position of Figure 6E.
[00133] Referring now to Figure 6G, and end view of the exhaust gas bypass
valve 138 is illustrated in the open position corresponding to Figure 6E.
[00134] Referring now to Figure 6H, the exhaust gas bypass valve 138 may be in
communication with an electrical motor 640. The electrical motor 640 has a
position
sensor 642 that provides feedback to a controller 644. The controller 644 is
coupled to
a plurality of sensors 646. The sensors provide feedback to the controller 644
to control
the position of the valve 614 of the exhaust gas bypass valve 138. The sensors
646
21
Date Recue/Date Received 2022-01-07
may include a boost pressure sensor, tuned pipe pressure sensor, exhaust
manifold
pressure sensor and a barometric pressure sensor. Other types of sensors that
may be
used for controlling the motor may include various types of temperature and
pressure
sensors for different locations within the vehicle.
[00135] Referring now to Figure 61, the turbine portion 510 is shown in
relation to
an exhaust gas bypass valve 138. In this example, a dual actuation system 650
is used
to simultaneously move the diverter valves 540, 550 and 560 illustrated above.
The
diverter valve 540 moves about the pivot pin 544. The exhaust gas bypass valve
138
opens and closes as described above. In this example, a rotating member 652 is
coupled to a first actuator arm 654 and a second actuator arm 656. As the
rotating
member 652 moves under the control of a motor 658, the first actuator arm 654
and the
second actuator arm 656 move. According to that described below. Each actuator
arm
654 and 656 may have a respective compensator 660, 662. Although the type of
movement described by the rotating member is rotating, other types of movement
for
the actuator arms may be implemented. A compensator 660, 662 may thus be
implemented in a plurality of different ways. The compensator 660, 662 may be
used to
compensate for the type of movement as described below.
[00136] In this example, when the rotating member 652 is in a starting or home
position, the exhaust gas bypass valve is closed and one scroll in the turbine
is closed.
As the dual actuation system 650 progresses the turbocharger scroll is opened
and the
diverter valve is positioned in a center position so that both scrolls are
open. As the
dual actuation system 650 progresses to the end of travel the exhaust gas
bypass valve
starts to open until it is fully open at the end of the actuator's travel. The
exhaust gas
22
Date Recue/Date Received 2022-01-07
bypass valve 138 does not start to open until the diverter valve is in the
neutral position
and both scrolls are open. Once both scrolls are opened further actuator
movement
results in no movement of the diverter valve in the turbo. The compensator
660, 662
may be slots or springs that allow the exhaust gas bypass valve to continue to
move.
The compensators may also be a stop on the diverter valve so that when a
diverter
valve hits the center position the stop may prevent the adjacent scroll from
being
closed. A compression spring or other type of compensator may be used so that
when
the stop is hit, the actuator rod allows the compensator 662 to compress, thus
still
allowing the actuator to turn the exhaust gas bypass valve 138. Of course,
various
types of mechanisms for the dual actuation system 650 may be implemented.
[00137] The wastegate may have a housing that is attached to a bracket for
supporting the wastegate actuator. The spring maintains the actuator in an
open
position should there be a mechanical or electrical fault.
[00138] Referring now to Figure 6J, the wastegate housing 610 is illustrated
in
further detail.
The wastegate housing 610 has the valve member 614 rotatably
coupled thereto as described above. The valve member 614 has a valve stem 617
on
which the valve member 614 rotates. The wastegate housing 610 has a bracket
672
that has a first arm 672A, a second arm 672B and a cross member 672C. The
first
arm 672A is coupled to the wastegate 610 at a first location spaced apart from
a
second location at which the arm 672B is coupled to the wastegate housing 610.
Bosses 674A, 674B may be integrally formed with the wastegate housing 610 or
may
be used to receive fasteners (not shown) that couple the respective arm 672A,
674B to
the bosses 674A, 674B. Bosses 674A, 674B may be integrally formed with the
23
Date Recue/Date Received 2022-01-07
wastegate housing 610 and are used to receive fasteners 675 that couple the
respective arm 672A, 674B to the bosses 674A, 674B. In the present example,
the
plane of the cross member 672C of the bracket 672 is perpendicular or normal
to the
axis formed by the valve stem 670.
[00139] A spring 676, as described above, may be used to maintain the actuator
in
a particular position, such as an open position or a closed position, during
operation.
As the valve member 614 rotates, exhaust gases from the tuned pipe are
communicated to bypass the turbocharger.
[00140] A drive housing 664 is coupled to the cross member 672C. The drive
housing 664 has a motor 666 with a motor shaft 666A as is best illustrated in
Figure
6K. The motor shaft 666A is coupled to a connection mechanism 667 that
ultimately is
coupled to a driveshaft 668. The connection mechanism 667 may comprise various
types of gears such as spur gears or worm gears. The connection mechanism 667
may also be a belt or a chain drive. As the motor 666 rotates the motor shaft
666A, the
connection mechanism 667 translates the motion and rotates the driveshaft 668.
The
driveshaft 668 is coupled to the valve stem 670 through a coupler 669. The
coupler
669 allows the driveshaft 668 to directly move the valve stem 670. A front
view of the
valve stem 670 coupled to the coupler 669 and the valve member 614 is
illustrated in
Figure 6L. In the example illustrated in Figure 6J, the coupler 669 is
disposed between
the wastegate housing 610 and the cross member 672C. Although not illustrated,
the
housing 674 may have a power connector 665 for powering the motor 666.
[00141] Referring now to FIGS. 6J and 6M, the coupler 669 may comprise a first
lever arm 680A that has an opening 680c therethrough. The coupler 669 may also
24
Date Recue/Date Received 2022-01-07
include a second lever arm 680B that has an opening 680d therethrough. The
lever
arm 680A is fixedly coupled to the driveshaft 668. The lever arm 680B is fixed
coupled
to the valve stem 670. A fastener such as a bolt 682A couples the lever arm
680B to
the lever arm 680A with the use of a nut 682B. Of course, other fasteners,
such as
rivet, screw, clip or pin, may be used to couple the lever arms together. When
the
lever arms 680A and 680B are coupled together, the longitudinal axes of the
driveshaft
668 and the valve stem 670 are coaxial. The movement of the lever arms 680A
and
680B cause the valve member 614 to rotate into the desired position to allow
exhaust
gases to be communicated from the pipe.
In particular, exhaust gases are
communicated from the center portion of the tuned pipe. In other examples,
exhaust
gases may be communicated in different ways and different positions relative
to the
engine including other positions of the tuned pipe.
[00142] Referring now to Figure 6N, an alternate location for the drive
housing 664
may be coupled to a bracket 680. The bracket 680, in this example, is coupled
to the
compressor housing or compressor portions 512 of the turbocharger 140. As was
described above, a turbine portion 510, which may be referred to as the
turbine
housing, is coupled to the compressor portion 512. The driveshaft 668 is
illustrated
coupled to a flexible drive or flexible coupling 681. The flexible coupling
681 is also
shown in more detail in Figure 60. The flexible coupling 681 has an outer
sheath 681A
and a rotating member 681B that rotates with the driveshaft 668. A fastener
682A
couples the driveshaft 668A to the rotating member 681B. A fastener 682B
couples
the rotating member 681B to the valve stem 670. Various types of fasteners may
be
used including but not limited to clips, rivets, screws and combinations
thereof. The
Date Recue/Date Received 2022-01-07
advantage of using a flexible coupling 681 is the location may be varied. The
bracket
680 may also be used in other locations of the vehicle, such as a frame or the
like (not
shown). This allows the bracket 680 and the drive housing 664 to be mounted in
a
number of different locations of the vehicle.
[00143] Referring now to Figure 6P, another position for a bracket 684 is
integrally
formed with the compressor housing 612. During the formation or molding of the
compressor housing 512, the bracket 684 may be integrally formed therein. The
reduces the overall part count of the system. The housing 664 is coupled to
the
bracket that is integrally formed with the compressor housing 512 using
fasteners 685
or the like. In this example, the exhaust bypass pipe 686 is also illustrated.
The
exhaust bypass pipe 686 was eliminated for clarity in Figure 6N. The exhaust
bypass
pipe communicates exhaust gases from the tuned pipe 47 and in particular the
center
portion 47B of the tuned pipe 47 to the silencer 710.
[00144] Referring now to Figure 6Q, a clamp 688 may be used to couple the
wastegate housing 610 to the center portion 47B of the tuned pipe 47. The
clamp 688
is coupled to a flange 689 that may be integrally formed with the center
portion 47B of
the tuned pipe 47. A flange 690 formed on the wastegate housing 610 may also
be
received in the clamp. A fastener 692 may be used to secure the clamp 688 to
the
flanges 689 and 690. In particular, a pair of grooves 694 on the internal
diameter of the
clamp 688 may receive the flanges 689, 690 for securing therein. The fasteners
692
may be tightened to couple the wastegate housing 610 to the flange 689.
[00145] Referring now to Figures 7A-7C, the position of the exhaust gas bypass
valve 138 relative to the turbocharger and the silencer of the vehicle may be
changed.
26
Date Recue/Date Received 2022-01-07
Although the turbocharger 140 is illustrated, the following descriptions may
be applied to
normally aspirated (non-turbocharged) engines.
[00146] Referring now specifically to Figure 7A, the engine assembly 40 has
the
exhaust manifold 45 as illustrated above. The tuned pipe 47 communicates
exhaust
gases from the exhaust manifold 45 to the stinger 134. The stinger 134 is in
communication with the turbocharger 140, and in particular the turbine inlet
524 of the
turbine portion 510. In a non-turbocharged engine the stinger 134 may be
communicated to the silencer 710. Exhaust gases pass through the turbine
portion 510
and exit through outlet 526 at a lower total energy. In this example the
bypass pipe
136A extends from the tuned pipe 47 to the exhaust pipe 142. In particular,
the bypass
pipe is illustrated in communication with the center portion 47B of the tuned
pipe 47.
The exhaust gas bypass valve 138 is positioned within the bypass pipe 136A.
The
outlet of the bypass pipe 136 communicates with the exhaust pipe 142 before a
silencer
710. The silencer 710 has an exhaust outlet 143.
[00147] An inlet source 712 communicates air to be compressed to the
compressor portion 512 of the turbocharger 140. The compressed air is
ultimately
provided to the engine assembly 40.
[00148] As shown is dotted lines, the bypass pipe 136A may also be coupled to
the exhaust manifold 45, the diverging portion 47A of the tuned pipe 47, the
converging
portion 47C of the tuned pipe or the stinger 134.
[00149] Should the turbocharger 140 be removed, the exhaust pipe 142 is
connected directly to the stinger 134. The inlet source 712 is not required.
27
Date Recue/Date Received 2022-01-07
[00150] Referring now to Figure 7B, the silencer 710 may include a plurality
of
chambers 720A-720C. In the example set forth in Figure 7B, all of the same
reference
numerals are used. However, in this example, the bypass pipe 136B communicates
exhaust gases around the turbocharger 140 by communicating exhaust gases from
the
center portion 47B of the tuned pipe 47 through the exhaust gas bypass valve
138 to a
first chamber 720A of the silencer 710. It should be noted that the outlet of
the bypass
pipe 136B is in the same chamber as the exhaust gases entering from the
exhaust pipe
142.
[00151] As shown in dotted lines, the bypass pipe 136B may also be coupled to
the exhaust manifold 45, the diverging portion 47A of the tuned pipe 47, the
converging
portion 47C of the tuned pipe or the stinger 134.
[00152] As in Figure 7A, should the turbocharger 140 be removed, the exhaust
pipe 142 is connected directly to the stinger 134. The inlet source 712 is not
required.
[00153] Referring now to Figure 7C, the bypass pipe 136C communicates
fluidically from the tuned pipe 47 to a first chamber 720A of the silencer
710. In this
example, the first chamber 720A is different than the chamber that the exhaust
pipe 142
from the turbocharger entering the silencer 710. That is, the exhaust pipe 142
communicates with a third chamber 720C of the silencer while the bypass pipe
136C
communicates with a first chamber 720A of the silencer 710. Of course,
multiple
chambers may be provided within the silencer 710. The example set forth in
Figure 7C
illustrates that a bypass pipe 136C may communicate exhaust gases to a
different
chamber than the exhaust pipe 142.
28
Date Recue/Date Received 2022-01-07
[00154] As in the above, should the turbocharger 140 be removed, the exhaust
pipe 142 is connected directly to the stinger 134. The inlet source 712 is not
required.
[00155] Referring now to Figure 7D, engine assembly 40 is illustrated having a
fourth example of an exhaust gas configuration. In this case, bypass pipe 136D
does
not connect to the exhaust pipe 142. The outlet of the exhaust gas bypass
valve 138
connects to the atmosphere directly or through a supplemental silencer 730
then to the
atmosphere. The configuration of Figure 7D is suitable if packaging becomes an
issue.
[00156] As shown is dotted lines, the bypass pipes 136C, 136D in Figures 7C
and
7D may also be coupled to the exhaust manifold 45, the diverging portion 47A
of the
tuned pipe 47, the converging portion 47C of the tuned pipe or the stinger
134.
[00157] As in the above, should the turbocharger 140 be removed, the exhaust
pipe 142 is connected directly to the stinger 134. The inlet source 712 is not
required.
[00158] Referring now to Figure 7E, a two-stroke engine system is set forth.
In the
present system an engine assembly 40 is coupled to an exhaust manifold 45. The
exhaust manifold 45 is in communication with the tuned pipe 47. The tuned pipe
47 has
a divergent portion 47A, a center portion 47B and a convergent portion 47C.
The
divergent portion 47A widens the tuned pipe 47 to the center portion 47B. The
center
portion 47B may be a relatively straight portion or a portion that has a
generally
constant cross-sectional area. The convergent portion 47C reduces the diameter
of the
center portion 47B to a diameter that is in communication with the stinger
134. Exhaust
gases from the exhaust manifold 45 travel through the divergent portion 47A
and the
center portion 47B and the convergent portion 47C in a "tuned" manner. That
is, the
portions 47A-47C are tuned for the particular design of the engine to provide
a certain
29
Date Recue/Date Received 2022-01-07
amount of back pressure. Thus, a certain amount of power and stability is
designed into
the engine assembly. The exhaust gases travel from the stinger 134 to a
silencer 710.
As described above a turbocharger 140 may be used to recover some of the
energy in
the exhaust gases. The tuned pipe 47 has a tuned pipe pressure sensor 734 that
is
coupled to the tuned pipe 47 to sense the amount of exhaust gas pressure
within the
tuned pipe 47. The tuned pipe pressure sensor 734 generates a signal
corresponding
to the exhaust gas pressure within the tuned pipe 47.
[00159] An exhaust gas bypass valve 740 in this example is coupled directly to
the
exhaust manifold 45. The exhaust gas bypass valve 740 provides a bypass path
through the bypass pipe 136 which may enter either the silencer 710 or
communicate
directly to atmosphere through a supplemental silencer 730. Of course, the
bypass pipe
136 may be configured as set forth above in the pipe between the turbocharger
140 and
the silencer 710. The exhaust gas bypass valve 740 may be electrically coupled
to a
controller as will be described further below. Based upon various engine
system sensor
signals, exhaust gas bypass valve 740 may be selectively opened to provide an
increase in power and or stability for the engine assembly 40. The exhaust gas
bypass
valve 740 changes the pressure within the tuned pipe 47 so the airflow through
the
engine is increased or decreased, by changing the differential pressure across
the
engine. A change in the airflow may be perceived as an increase in power,
engine
stability or improved combustion stability or a combination thereof.
[00160] Referring now to Figure 7F, the exhaust gas bypass valve 740' may be
disposed on the center portion 47B of the tuned pipe 47. However, the exhaust
gas
bypass valve 740' may also be located on the divergent portion 47A or the
convergent
Date Recue/Date Received 2022-01-07
portion 47C as illustrated in dotted lines. In the example set forth in Figure
7F the
exhaust gas bypass valve 740' is mounted directly to the outer wall 741 of the
center
portion 47B of the tuned pipe 47. The exhaust gas bypass valve 740' may also
be
coupled to the stinger 134 also as illustrated in dotted lines.
[00161] Referring now to Figure 7G, the exhaust gas bypass valve 740" may be
positioned away from the outer wall 741 of the tuned pipe 47 by a standoff
pipe 742.
The standoff pipe 742 may be very short such as a few inches. That is, the
standoff
pipe 742 may be less than six inches. Thus, the exhaust gas bypass valve 740"
may be
positioned in a desirable location by the standoff pipe 742 due to various
considerations
such as packaging.
[00162] In this example standoff pipe 742 and hence the exhaust gas bypass
valve 740" is coupled to the center portion 47B of the tuned pipe 47. However,
as
illustrated in dotted lines, the standoff pipe 742 may be may be coupled to
the exhaust
manifold 45, the diverging portion 47A, the converging portion 47C or the
stinger 134.
[00163] The valve 740" may also be located within the center portion 47B of
the
tuned pipe 47. The valve 740" may also be located within the divergent portion
47A or
the convergent portion 47C or in the exhaust manifold as illustrated in dotted
lines.
[00164] Referring now to Figure 7H, a control valve 740" may be disposed
within
the stinger 134. The valve 740" may not communicate bypass exhaust gasses out
of
the exhaust stream but the control valve 740" may be configured in a similar
manner as
the exhaust gas bypass valves described above with controlled flow
therethrough.
Valve 740" may be partially opened in the most closed position to allow some
exhaust
gasses to flow there through. Although the valve 740" may be used in a
turbocharged
31
Date Recue/Date Received 2022-01-07
application, a normally aspirated engine application may be suitable as well.
The valve
740" may open in response to various conditions so that the power output of
the engine
may be adjusted depending on such inputs as throttle, load engine speed, tuned
pipe
pressure and temperature, exhaust pressure and temperature. Other location of
the
control valve 740" are also illustrated in the diverging portion 47A of the
tuned pipe 47,
the middle portion 47B and the converging portion 47C of the tuned pipe.
[00165] The exhaust gas bypass valves 740, 740', 740" and 740" may have
various types of configurations. In one example the exhaust gas bypass valve
740-
740" may be configured as an exhaust gas bypass valve similar to that set
forth above
and used to bypass the turbocharger 140. The structural configuration of the
valves
740-740" may include but are not limited to a butterfly valve, a slide valve,
a poppet
valve, a ball valve or another type of valve.
[00166] Referring now to Figure 71, the exhaust bypass valve 740 illustrated
above
may be implemented within a first chamber 720A of the silencer 710. In this
example,
the tuned pipe 47 communicates exhaust gasses to the silencer 710. The tuned
pipe 47
may communicate exhaust gasses from a first portion 747A, a center portion
747B, or a
third portion 747C. These are illustrated in the above examples. The exhaust
bypass
valve 740" is disposed within one of the chambers 720A-720C. In this example,
the
exhaust bypass valve 740" is disposed within the first chamber 720A. In this
example,
the turbocharger140 communicates exhaust gasses to the silencer through the
pipe
142. In this example, the turbocharger140 is coupled to the pipe 142 which is
in
communication with the first chamber 720A. However, any one of the chambers
720A-
720C may receive exhaust gasses from the turbocharger140 through the pipe 142.
32
Date Recue/Date Received 2022-01-07
[00167] Referring now to Figure 7J, the chamber 720A illustrated in Figure 1
is
divided into a first chamber portion 720A' and a second chamber portion 720A"
which
are separated by a wall 746. Exhaust gasses are communicated between the first
chamber portion 720A' and the second chamber portion 720A" through the exhaust
bypass valve 7401v.
[00168] The valve 740" and 7401v are provided to control the amount of
pressure
in various tuning characteristics of the tuned pipe 47. In Figure 7J, the
turbocharger140
may be in communication with any one of the chambers 720A", chamber 720B, and
chamber 720C.
[00169] Any of the chambers 720A-C may be divided into two chambers.
[00170] Referring now to Figure 7K, the supplemental silencer 730 and the
silencer 710 may be disposed as a single unit. The supplemental silencer 730
may be
disposed in a common housing but maintain separate flow paths from the valve
138 and
the turbocharger 140. The silencer 710 and the supplemental silencer 730 may
have a
common wall 724 therebetween. The common wall reduces manufacturing costs and
vehicle weight by reducing the amount of wall material.
[00171] Referring now to Figure 7L, a simplified version of Figures 7A through
7K
is set forth. In Figures 7L through 7N, components such as the engine assembly
and all
of the piping is eliminated for simplicity purposes. Of course, although the
turbocharger
140 is illustrated, the turbocharger 140 in Figures 7L through 7N correspond
to the
turbine portion of the turbocharger 140.
[00172] Referring now specifically to Figure 7L, the turbocharger 140 receives
exhaust gases from the stinger and tuned pipe which originated from the
engine. The
33
Date Recue/Date Received 2022-01-07
wastegate 740 receives bypass exhaust gases from the tuned pipe. The muffler
750
receives exhaust gases from the pipe 142 at port 750A and exhaust gases from
pipes
136D at port 750B. The muffler 750 may be one singular muffler or may include
a
separate wall 752 to keep the exhaust gases separate. That is, wall 752 is an
optional
component. A pipe 754 is coupled to both sides of the wall 752 and receive
exhaust
gases from each side of the muffler 750. That is, exhaust gases that
originated at port
750A and 750B are ultimately combined in the pipe 754.
[00173] Referring now to Figure 7M, pipe 142 from turbocharger 140 and pipe
136D from the wastegate 740 are joined together at a joint 756. The joint is a
Y-joint
that comes together before the silencer 710. Ultimately, the silencer 710 so
that the
silencer 3 710 includes one inlet pipe 758 and one outlet pipe760.
[00174] Referring now Figure 7N, the pipe 758 is coupled to a flange 762 prior
to
entering the silencer 710. In a practical example, the flange 762 and the
joint 756 may
all be formed as one component. The flange 762 may be used to increase the
manufacturability of the configuration.
[00175] Referring now to Figure 70, the engine assembly 40, the tuned pipe 47
and the turbocharger 140 are all illustrated. The wastegate or exhaust bypass
valve
740 is illustrated coupled to the center section 47B. In this example, the
effective area
of cross-sectional flow of the wastegate or exhaust bypass valve 740 is
greater than the
cross-section flow area of the stinger 134. Correspondingly, the cross-
sectional flow
area of the pipes 136D and 136 also have a cross-sectional flow area about or
greater
than that of the cross-sectional flow area of the wastegate or exhaust bypass
valve 740.
34
Date Recue/Date Received 2022-01-07
[00176] Referring now to Figure 8A, schematic view of an engine air system
that a
boost box 810 is illustrated. The boost box 810 has a one-way valve 812
coupled
therein. The valve 812 may be an active valve such as a motor controlled valve
or a
passive valve such as a reed valve. When a lower pressure is present in the
boost box
810 than the ambient pressure outside the boost box 810, the valve 812 opens
and
allows air to bypass the compressor portion 512 of the turbocharger 140. That
is, a
bypass path is established through the boost box from the valve 812 through
boost box
810 to the engine. That is, the air through the valve 812 bypasses the
compressor
portion 512 of the turbocharger 140 and the air in boost box 810 is directed
to the air
intake or throttle body of the engine assembly 40.
[00177] The one-way valve 812 may be a reed valve as illustrated in further
detail
in Figure 8F. By using a one-way valve 812, engine response is improved to
activate
turbocharger 140 sooner. When the engine response is improved the turbocharger
lag
is reduced by allowing the engine to generate exhaust mass flow quicker, in
turn forcing
the turbine wheel speed to accelerate quicker. When the compressor portion 512
of the
turbocharger 140 builds positive pressure the one-way valve 812 closes. When
implemented, a decrease in the amplitude and duration of the vacuum present in
the
boost box 810 was achieved. In response, the engine speed increased sooner,
and the
compressor built positive pressure sooner.
[00178] Referring now to Figures 8A-8F, the boost box 810 has the one-way
valve
812 as described above. The one-way valve 812 allows air into the boost box
810 while
preventing air from leaving the boost box 810. The boost box 810 also includes
a
compressor outlet 814. The compressor outlet 814 receives pressurized air from
the
Date Recue/Date Received 2022-01-07
compressor portion 512 of the turbocharger 140. However, due to turbocharger
lag the
compressor takes some time to accelerate and provide positive pressure to the
boost
box 810 particularly when wide open throttle is demanded suddenly from a
closed or
highly throttled position.
[00179] The boost box 810 also includes a pair of intake manifold pipes 816
that
couple to the throttle body 90 of the engine assembly 40.
[00180] A portion of a fuel rail 820 is also illustrated. The fuel rail 820
may be
coupled to fuel injectors 822 that inject fuel into the boost box 810 or
throttle body 90.
The fuel rail 820 and fuel injectors 822 may also be coupled directly to the
throttle body
90.
[00181] A pressure sensor 824 may also be coupled to the boost box 810 to
generate an electrical signal corresponding to the amount of pressure in the
boost box
810, which also corresponds to the boost provided from the compressor portion
512 of
the turbocharger 140. The boost box pressure sensor signal takes into account
the
boost pressure and the barometric pressure. That is the boost box pressure
sensor
signal is a function of both the boost pressure and the barometric pressure.
[00182] Referring now to Figure 8F, the one-way valve 812 is illustrated in
further
detail. The one-way valve 812 may include a plurality of ports 830 that
receive air from
outside of the boost box 810 and allow air to flow into the boost box 810.
That is, when
a lower pressure is developed within the boost box 810 such as under high
acceleration
or load, the turbocharger 140 is not able to provide instantaneous boost and
thus air to
the engine is provided through the one-way valve 812 to reduce or eliminate
any
negative pressure, relative to ambient pressure outside the boost box, within
the boost
36
Date Recue/Date Received 2022-01-07
box 810. When compressor portion 512 of the turbocharger 140 has reached
operating
speed and is pressurizing the boost box 810, the pressure in the boost box 810
increases and the one-way valve 812 closed. That is, the ports 830 all close
when
pressure within the boost box 810 is higher than the ambient pressure outside
the boost
box.
[00183] Referring now to Figure 8G, the boost box 810 is illustrated within an
engine compartment 832. The engine compartment 832 roughly illustrates the
engine
assembly 40 and the turbocharger 140. In this example the one-way valve 812 is
illustrated rearward relative to the front of the vehicle. The position of the
one-way valve
812 allows cooler air to be drawn into the boost box 810.
[00184] Referring now to Figure 8H, the one-way valve 812 may be coupled to a
duct 840. The duct 840 allows cooler air to be drawn into the boost box 810
from a
remote location. In this example, an upper plenum 842 is coupled to the duct
840. The
upper plenum may pass the air through a filter 862, such as a screen or fine
mesh, prior
to being drawn into the boost box 810. The filter 862 may filter large
particles and
prevent damage to the boost box 810 and the one-way valve 812. The upper
plenum
receives air from a vent 846. A filter 862' may be located at the vent 846 or
between the
vent 846 and upper plenum 842. Of course, in one system one filter 862 or the
other
filter 862' may be provided.
[00185] The vent 846 may be located in various places on the vehicle. For
example, the vent 846 may draw air externally though the hood of the vehicle,
the
console of the vehicle or from a location under the hood that has clean and
cool air.
37
Date Recue/Date Received 2022-01-07
[00186] Referring now to Figure 81, a channel 850 may be formed in the fuel
tank
852. That is, the channel 850 may act as the duct 840 illustrated above in
Figure 8H.
The channel 850 may be integrally formed into the outer walls 854 of the fuel
tank. The
boost box 810 may be attached to the fuel tank 852 so that the air drawn into
the boost
box 810 is received through the channel 850. A seal 856 may be used between
the
boost box and the fuel tank 852 so that the air is completely drawn through
the channel
850. Various types of seals may be used. Rubber, foam, thermoplastics are some
examples. The seal 856 may be a gasket. A duct 860 may be coupled between the
fuel
tank 852 and the boost box 810 to receive air from a remote location such as
the vent
846 illustrated in Figure 8H or another location within the engine compartment
832 of
the vehicle. Of course, the duct 860 may draw air from other portions of the
vehicle or
outside the vehicle. A filter or screen 862 may be used to prevent debris from
entering
the channel 850.
[00187] Referring now to Figure 9A, a block diagrammatic view of a control
system
for a two-stroke turbocharged engine is set forth. In this example a
controller 910 is in
communication with a plurality of sensors. The sensors include but are not
limited to a
boost pressure sensor 912, an engine speed sensor 914, an atmospheric
(altitude or
barometric) pressure sensor 916, a throttle position sensor, tuned pipe
pressure sensor
734, an exhaust valve position sensor 937 and an exhaust manifold pressure
sensor.
Each sensor generates an electrical signal that corresponds to the sensed
condition.
By way of example, the boost pressure sensor 912 generates a boost pressure
sensor
signal corresponding to an amount of boost pressure. The engine speed sensor
914
generates an engine speed signal corresponding to a rotational speed of the
crankshaft
38
Date Recue/Date Received 2022-01-07
of the engine and the atmospheric or barometric pressure sensor 916 generates
a
barometric pressure signal corresponding to the atmospheric ambient pressure.
[00188] The tuned pipe pressure sensor 734 may also be in communication with
the controller 910. The tuned pipe pressure sensor 734 generates a tuned pipe
pressure signal corresponding to the exhaust pressure within the tuned pipe 47
as
described above. The exhaust valve position sensor 937 generates an exhaust
valve
position signal corresponding to the position of the exhaust valve. The
exhaust
manifold pressure sensor 939 generates a signal corresponding to the pressure
in the
exhaust manifold. A vehicle speed sensor 939A generates a speed signal
corresponding to the speed of the vehicle. An exhaust gas temperature sensor
939B
generates an exhaust gas temperature signal, an exhaust valve position sensor
939C
generates an exhaust valve position signal, and a post compressor temperature
sensor
939D generates a temperature signal of the temperature of the exhaust after
the
compressor.
[00189] The controller 910 is used to control an actuator 920 which may be
comprised of an exhaust gas bypass valve actuator 922 and exhaust gas diverter
valve
actuator 924. An example of the actuator is illustrated in Figure 61 above. Of
course, as
mentioned above, the actuators may be one single actuator. The actuator 922 is
in
communication with the exhaust gas bypass valve 138. The actuator 924 is in
communication with the exhaust gas diverter valve 540. The controller 910
ultimately
may be used to determine an absolute pressure or a desired boost pressure.
[00190] A boost error determination module 930 is used to determine a boost
error. The boost error is determined from the boost pressure sensor 912 in
comparison
39
Date Recue/Date Received 2022-01-07
with the desired boost pressure from the boost pressure determination module
932.
The boost pressure error in the boost pressure determination module 930 is
used to
change an update rate for determining the boost pressure for the system. That
is, the
boost error determination is determined at a first predetermined interval and
may be
changed as the boost error changes. That is, the system may ultimately be used
to
determine an update rate at a faster rate and, as the boost pressure error is
lower, the
boost pressure determination may determine the desired boost pressures at a
lower or
slower rate. This will be described in further detail below. This is in
contrast to typical
systems which operate a PID control system at a constant update rate.
Ultimately, the
determined update rate is used to control the exhaust gas bypass valve using
an
exhaust gas bypass valve position module 934 which ultimately controls the
actuator
920 or actuator 922 depending if there is a dedicated actuator for the exhaust
gas
bypass valve 138. By determining the boost target in the boost pressure
determination
module 932, the update rate may be changed depending on the amount of boost
error.
By slowing the calculations, and subsequent system response, during the
approach of
the target boost value, overshoot is controlled and may be reduced. Also, the
update
rate may be increased to improve system response when large boost errors are
observed.
[00191] The controller 910 may be coupled to a detonation sensor 935. The
detonation sensor 935 detects detonation in the engine. Detonation may be
referred to
as knock. The detonation sensor 935 may detect an audible signal.
[00192] The controller 910 may also include an absolute pressure module 936
that
keeps the engine output constant at varying elevations. That is, by comparing
the
Date Recue/Date Received 2022-01-07
altitude or barometric pressure from the atmospheric pressure sensor 916, the
boost
pressure may be increased as the elevation of the vehicle increases, as well
as to
compensate for increased intake air charge temperature due to increased boost
pressure to maintain constant engine power output. This is due to the
barometric
pressure reducing as the altitude increases. Details of this will be set forth
below.
[00193] The controller 910 may also include a second exhaust gas bypass valve
position control module 938. The exhaust gas bypass valve position control
module
938 is used to control the exhaust gas bypass valve and position the actuator
926 which
may include a motor or one of the other types of valve described above. The
exhaust
gas bypass valve position control module 938 may be in communication with the
sensors 912-918, 935 and 734. The amount of pressure within the tuned pipe may
affect the stability and power of the engine. Various combinations of the
signals may be
used to control the opening of the exhaust gas bypass valve 740-740". The
exhaust
gas bypass valves 740-740" may, for example, be controlled by feedback from
the
tuned pipe pressure sensor 734. The tuned pipe pressure sensor signal may be
windowed or averaged to obtain the pressure in the tuned pipe as a result of
the
opening or closing of the exhaust gas bypass valve 740-740". The tuned pipe
pressure
sensor 734 may be used in combination with one or more of the other sensors
912-918,
734 and others to control the opening and closing of the exhaust gas bypass
valve 740-
740". The boost pressure or average boost pressure from the boost pressure
sensor
912 may also be used to control the exhaust gas bypass valves 740-740". The
boost
pressure determination module 932 may provide input to the exhaust gas bypass
valve
41
Date Recue/Date Received 2022-01-07
position control module 938 to control the exhaust gas bypass valve based upon
the
boost pressure from the boost pressure determination module 932 as described
above.
[00194] A map may also be used to control the specific position of the exhaust
gas
bypass valve 740-740". For example, the engine speed signal, the throttle
position
signal and/or the barometric pressure signal may all be used together or alone
to open
or close the exhaust gas bypass valve 740-740" based on specific values stored
within
a pre-populated map.
[00195] Referring now to Figure 9B, in step 940 the actual boost pressure is
measured by the boost pressure sensor 912 as mentioned above. In step 942 a
boost
pressure error is determined. Because this is an iterative process, the boost
error is
determined by the difference between the target boost and the actual boost
pressure.
Once the process is cycled through once, a boost error will be provided to
step 942.
[00196] Referring to step 944, the update interval is changed based upon the
boost error determination in step 942. That is, the boost error is used to
determine the
update rate of the exhaust gas bypass valve control method. That is, the
update rate
corresponds to how fast the method of determining error, then moving the
exhaust gas
bypass valve actuator, and determine timing of the next cycle is performed. As
mentioned above, as the actual boost or measured boost pressure becomes closer
to
the target boost pressure the update rate is reduced in response to the
observed boost
error.
[00197] In step 946 a desired absolute pressure is established. Step 946 may
be
established by the manufacturer during the vehicle development. The desired
absolute
pressure may be a design parameter. In step 948 the barometric pressure of the
42
Date Recue/Date Received 2022-01-07
vehicle is determined. The barometric pressure corresponds to the altitude of
the
vehicle. In step 950 a required boost pressure to obtain the absolute pressure
and
overcome additional system losses due to elevation is determined. That is, the
barometric pressure is subtracted from the required absolute pressure to
determine the
desired boost pressure. In step 952 the exhaust gas bypass valve and/or the
exhaust
gas diverter valve for the twin scroll turbocharger is controlled to obtain
the desired
boost pressure. Because of the mechanical system the desired boost pressure is
not
obtained instantaneously and thus the process is an iterative process. That
is, the
required boost pressure from step 950 is fed back to step 942 in which the
boost error is
determined. Further, the after step 952 step 940 is repeated. This process may
be
continually repeated during the operation of the vehicle.
[00198] Referring now to Figure 9C, a throttle position sensor 918 may provide
input to the controller 910. The throttle position sensor signal 954 is
illustrated in Figure
9C. The engine speed signal 960 is also illustrated. The signal 958
illustrates the
position of the exhaust gas bypass valve. The signal 956 illustrates the
amount of boost
error.
[00199] Referring now to Figure 9D, a plot of a calculation multiplier delay
versus
the absolute boost error pressure is set forth. As can be seen as the boost
error
decreases the frequency of calculations decreases. That is, as the boost error
increases the frequency of calculations increases.
[00200] Referring now to Figure 9E, a plot of absolute manifold pressure
versus
elevation is set forth. The barometric pressure and the boost pressure change
to obtain
the total engine power or target absolute pressure. That is, the absolute
pressure is a
43
Date Recue/Date Received 2022-01-07
design factor that is kept relatively constant during the operation of the
vehicle. As the
elevation increases the amount of boost pressure also increases to compensate
for the
lower barometric pressure at higher elevations as well as increased intake air
temperature.
[00201] Referring now to Figure 9F, a method for operating the exhaust gas
bypass valve 740-740" is set forth. In this example the various engine system
sensors
are monitored in step 964. The engine sensors include but are not limited to
the boost
sensor 912, the engine speed sensor 914, the altitude/barometric pressure
sensor 916,
the throttle position sensor 918 and the tuned pipe pressure sensor 734.
[00202] In step 966 the exhaust gas bypass valve 740-740" is adjusted based
upon the sensed signals from the sensors. The adjustment of the opening in
step 966
may be calibrated based upon the engine system sensors during development of
the
engine. Depending upon the desired use, the load and other types of
conditions,
various engine system sensors change and thus the amount of stability and
power may
also be changed by adjusting the opening of the exhaust gas bypass valve.
[00203] In step 968, the pressure within the tuned pipe is changed in response
to
adjusting the opening of the exhaust gas bypass valve 740-740". In response to
changing the pressure within the tuned pipe, the airflow through the engine is
changed
in step 969. When the airflow through the engine is changed the stability of
the engine,
the power output of the engine or the combustion stability or combinations
thereof may
also be improved. It should be noted that the opening of the exhaust gas
bypass valve
740-740" refers to the airflow though the exhaust gas bypass valve 740-740".
Thus,
the opening may be opened and closed in response to the engine system sensors.
44
Date Recue/Date Received 2022-01-07
[00204] Referring now to Figure 9G, the exhaust gas bypass valve position
control
module 934 is illustrated in further detail. As mentioned above, the exhaust
gas bypass
valve effective area may be varied depending on various operating conditions.
The
addition of a turbocharger to a two-stroke engine adds the restriction of the
turbine
which causes the engine to respond slower than a naturally aspirated engine of
similar
displacement. The loss of response caused from the turbine may be viewed by a
vehicle operator as turbocharger lag.
[00205] The exhaust gas bypass valve position module 934 is illustrated having
various components used for controlling the exhaust gas bypass valve. An idle
determination module 970 is used to receive the engine speed signal. The idle
determination module may determine that the engine speed is below a
predetermined
speed. A range of speeds may be used to determine whether or not the engine is
at
idle. For example, a range between about 1000 and 2000 rpms may allow the idle
determination module 970 to determine the engine is within or at an idle
speed. Idle
speeds vary depending on the engine configuration and various other design
parameters. Once the engine is determined to be at idle the exhaust gas bypass
valve
effective area module 972 determines the desired effective exhaust gas bypass
valve
area for the exhaust gas bypass valve. The exhaust gas bypass valve effective
area
module 972 determines the opening or effective area of the exhaust gas bypass
valve
for the desired control parameter. For idle speed, a first effective exhaust
gas bypass
valve area may be controlled. That is, one effective exhaust gas bypass valve
area
may be used for idle speed determination. Once the exhaust gas bypass valve
area is
determined the exhaust gas bypass valve actuator 922 may be controlled to open
the
Date Recue/Date Received 2022-01-07
exhaust gas bypass valve a first predetermined amount. The exhaust gas bypass
valve
for idle may be opened a small effective area. That is, the exhaust gas bypass
valve
may be opened further than a fully closed position but less than a fully
opened position.
For exhaust gas bypass valve such as those illustrated in Figure 6 above about
twenty
degrees of opening may be commanded during the idling of the two-stroke
engine. By
opening the exhaust gas bypass valve a predetermined amount some of the
exhaust
gases are bypassed around both the turbine portion 510 of the turbocharger 140
and
the stinger 134 at the end of the tuned pipe.
The effective predetermined area may
change depending on various sensors including but limited to in response to
one or
more of the engine speed from the engine speed sensor, throttle position from
the
throttle position sensor or a detonation from the detonation sensor.
[00206] The exhaust gas bypass valve position control module 934 may also
control the exhaust gas bypass valve position during acceleration or to
improve engine
stability. Acceleration of the engine may be determined in various ways
including
monitoring the change in engine speed, monitoring the throttle position or
monitoring the
load on the engine. Of course, combinations of all three may be used to
determine the
engine is accelerating. When the engine is accelerating as determined in the
acceleration determination module 974 the exhaust gas bypass valve effective
area
module 972 may hold the exhaust gas bypass valve open a predetermined amount.
The predetermined amount may be the same or different than the predetermined
amount used for the engine idle. Again, some of the exhaust gases are bypassed
around the stinger 134 and the turbine portion 510 of the turbocharger 140.
The
determined exhaust gas bypass valve effective area is then commanded by the
exhaust
46
Date Recue/Date Received 2022-01-07
gas bypass valve effective area module 972 to control the exhaust gas bypass
valve
actuator module 922. In a similar manner, the engine sensor may be used to
monitor
engine stability. In response, the wastegate may open for various amounts of
time to
increase engine stability.
[00207] Referring now to Figure 9H, a method for operating the exhaust gas
bypass valve in response to acceleration and idle is set forth. In step 980
the engine
speed is determined. As mentioned above, the crankshaft speed may be used to
determine the speed of the engine. In step 982 is to determine whether the
engine is at
idle. Determining the engine is at idle may be performed by comparing the
engine
speed to an engine speed threshold or thresholds. When the engine speed is
below the
engine speed threshold or between two different engine speed thresholds, the
engine is
at idle. When the engine is at idle, step 984 determines an effective area for
the
exhaust gas bypass valve and opens the exhaust gas bypass valve accordingly.
In step
986 some of the exhaust gases are bypassed around the stinger 134 and the
turbine
portion 510 as described above.
[00208] When the engine is not at idle in step 982 and after step 986, step
988
determines whether the engine is in an acceleration event. As mentioned above,
the
acceleration event may be determined by engine speed alone, load alone or the
throttle
position or combinations of one or more of the three. When the engine is in an
acceleration event step 990 holds the exhaust gas bypass valve to a
predetermined
amount to reduce the backpressure. The predetermined amount may be the same
predetermined amount determined in step 984. The effective area may be
controlled by
the valve in the exhaust gas bypass valve or another type of opening control
in a
47
Date Recue/Date Received 2022-01-07
different type of exhaust gas bypass valve. In step 992 some of the exhaust
gases are
bypassed around the stinger 134 and turbine portion 510.
[00209] Referring back to step 988, if the engine is not in an acceleration
event the
engine operates in a normal manner. That is, in step 994 the boost pressure or
exhaust
backpressure is determined. In step 996 the exhaust gas bypass valve opening
is
adjusted based upon the boost pressure, the exhaust backpressure or both.
After step
996 and step 992 the process repeats itself in step 980.
[00210] Referring now to Figures 10A, 10B, 10C and 10D, the compressor wheel
519, the turbine wheel 520 and the shaft 521 are illustrated in further
detail. The
compressor wheel 519 is used to compress fresh air into pressurized fresh air.
The
compressor wheel 519 includes an inducer diameter 1010 and an exducer diameter
1012. The inducer diameter 1010 is the narrow diameter of the compressor
wheel. The
exducer diameter 1012 is the widest diameter of the compressor wheel 519.
[00211] The turbine wheel 520 includes an exducer diameter 1020 and an inducer
diameter 1022. The exducer diameter 1020 is the small diameter of the turbine
wheel
520. The inducer diameter 1022 is the widest diameter of the turbine wheel
520. That
is, the top of the blades 1024 have the exducer diameter 1020 and the lower
portion of
the blades 1024 have the inducer diameter 1022. The exducer diameter 1020 is
smaller than the inducer diameter 1022. The area swept by the blades 1024 is
best
illustrated in Figure 10C which shows the exducer area 1030 and the inducer
area
1032. The area of the port of the exhaust gas bypass valve was described above
relative to Figure 6G. The port area is the amount of area available when the
valve
member 614 is fully open. By sizing the area of the exhaust gas bypass valve
port in a
48
Date Recue/Date Received 2022-01-07
desirable way the operation of the two-stroke engine performance is increased.
As has
been experimentally found, relating the exhaust gas bypass valve effective
area (port
area) to the area of the turbine wheel exducer is advantageous. The exducer
area 1030
may be determined by the geometric relation 7 times half of the exducer
diameter
squared. By way of a first example, the port area for a two-stroke engine may
be
greater than about thirty-five percent of the exducer area. The port area of
the exhaust
gas bypass valve may be greater than about fifty percent of the exducer area.
In other
examples the port area of the exhaust gas bypass valve may be greater than
about
sixty percent of the exducer area. In another example the port area of the
exhaust gas
bypass valve may be greater than about sixty-five percent of the exducer area.
In yet
another example the port area of the exhaust gas bypass valve may be greater
than
about sixty-five percent and less than about ninety percent of the exducer
area. In
another example the port area of the exhaust gas bypass valve may be greater
than
about sixty-five percent and less than about eighty percent of the exducer
area. In yet
another example the port area of the exhaust gas bypass valve may be greater
than
about seventy percent and less than about eighty percent of the exducer area.
In yet
another example the port area of the exhaust gas bypass valve may be greater
than
about seventy-five percent and less than about eighty percent of the exducer
area.
[00212] As is mentioned above, the exhaust gas bypass valve may be
incorporated into a two-stroke engine. The exhaust gas bypass valve may be in
communication with the tuned pipe 47 and bypassing the turbocharger through a
bypass pipe 136. The exhaust gas bypass valve 138 may be coupled to the center
portion of the tuned pipe 47 The effective area of the port is determined
using the
49
Date Recue/Date Received 2022-01-07
diameter Pi shown in Figure 6G and subtracting the area of the valve member
614 and
the axle 618.
[00213] Referring now to Figure 10D, a plot of the ratio/percentage of exhaust
gas
bypass valve or bypass valve area to exducer area for known four stroke
engines, two
stroke engines and the present example are illustrated. As was observed,
providing a
higher ratio improved engine performance. The ratios or percentages may be
used is
four stroke and two stroke engines. From the data set forth is Figure 10D,
four stoke
engines have a maximum ratio of the port area to the exducer area of .5274 or
52.74
percent and for two stroke engines a 35.54 percentage port area to exducer
area was
found.
[00214] Referring now to Figure 11A, a portion of the controller 910
illustrated in
Figure 9A is set forth. One or more sensors 1110 are used to generate sensors
signals
that are communicated to a boost pressure set point 1112. The sensors 1110 may
include one or more of the sensors illustrated in Figure 9A such as the boost
pressure
sensor 912, the engine speed sensor 914, the atmospheric pressure sensor 916,
the
throttle position sensor 918, the tuned pipe pressure sensor 734, the exhaust
valve
position sensor 937, the exhaust manifold pressure sensor 939 and the
denotation
sensor 935. In particular, the sensors such as the engine speed sensor 914,
the throttle
position sensor 918, the exhaust manifold pressure sensor 939, the vehicle
speed
sensor 939A, the exhaust gas temperature sensor 939B,the exhaust valve
position
sensor 939C, and the post compressor temperature sensor 939D may be used to
determine a boost pressure set point. The measured boost pressure from the
boost
Date Recue/Date Received 2022-01-07
pressure sensor 912 is communicated to a summation block 1114. From this, a
boost
error is determined.
[00215] Minimizing actuator movement at the boost target set point is
important for
engine performance because it creates a constant and predictable airflow
through the
bypass system for consistent engine speed and minimizes wear to the electronic
actuator. A PID controller 1116 may be part of the controller 910. The PID
controller
uses the boost error to determine the gains to be used to change the position
of the
wastegate actuator. Ultimately, the gain Kp, Ki and Kd are determined at
blocks 1118,
1120 and 1122, respectively. The gains are determined from a look-up table
1124 in
one example. Other examples for determining the gains are provided below. As
set
forth in more detail below, the distance from the set point or a threshold or
thresholds
may be used to compare to the boost error determined in the boost error
determination
module 930. The gains determined in boxes 1118-1122 are used as part of the
system
transfer function 1130. Ultimately, the exhaust valve position control module
934 uses
the gains to determine an amount of wastegate position change that is desired
from the
current position. The change of the wastegate position is ultimately measured
by the
boost pressure sensor error 912.
[00216] Referring now also to Figure 11B, the boost pressure set point 1112 is
illustrated graphically relative to a first boost pressure threshold 1140 and
a second
boost pressure threshold 1142. The boost error may be a positive number or a
negative
number. That is, error is the boost pressure minus the target pressure. When
the boost
pressure is greater than the target value at a value above the threshold 1140,
high
gains may be provided. The high gain corresponds to a high wastegate position
51
Date Recue/Date Received 2022-01-07
change. When the target pressure is much greater than the boost pressure, the
value
might be significantly negative and therefore past or lower than the threshold
1142. A
high gain with a high wastegate position change may be provided. In the area
between
the first threshold 1140 and the second threshold 1142, low wastegate change
may be
provided. That is, only a small amount of wastegate position change may be
desired in
the area between the thresholds 1140 and 1142. This helps mitigate over-boost
or
over-shoot situations on a transient response. The system is used for a two
stroke
application in which it is desirable to have a fast response and stable
actuator
movement between near the set point. A typical PID controller may present an
undesirable situation in trying to balance two competing requirements. The use
of
variable gains allows a more flexible pressure control loop to provide fast
pressure
response on transient situations while providing exceptional PID control
stability at the
set point due to the reduced gains which translate to smaller wastegate
positions
changes. The use of variable gains may also be gradual in the look-up table.
That is,
as the distance from the boost set point increases, the amount of change may
increase
in the positive and negative directions. This control system also reduces the
need for
individual term dead-bands near the set point because the gains can be brought
to near
zero to prevent cycling about the set point on a highly unstable airflow
system. The
pressure stability is also increased because undershoot and over compensation
of PID
control near the set point is prevented.
[00217] Referring now to Figure 11C, a method of operating the system is set
forth. In this example, the actual boost pressure is measured at step 1150. In
step
1152, the boost set point is determined. The boost set point may be determined
from
52
Date Recue/Date Received 2022-01-07
various sensors including sensors indicative of the desired response from the
system
operator including the throttle position. In step 1154, the boost error is
determined by
comparing or subtracting the actual boost pressure and the boost set point.
After step
1154, three alternatives are provided for ultimately changing the wastegate
position
based upon the wastegate position change signal as is determined. In step
1156, the
wastegate position change signal that is based on the boost error signal is
derived from
the look-up table. As mentioned above, a low amount of gain or a low amount of
wastegate position change is determined close to the set point. After step
1156, the
wastegate position based on the wastegate position change signal is generated.
Ultimately, the system continually repeats at step 1150. In step 1158, the
wastegate
position may be based upon the amount of distance above or below a set point.
The
amount of wastegate position change may be directly calculated based upon the
boost
pressure amount above or below a boost set point. This may be a linear or non-
linear
function. In step 1160, it is determined whether the boost error is greater
than a
threshold. The boost error may be an absolute value of the boost error because
the
boost error may be above or below the set point, thus being a negative number.
When
the boost error is greater than the threshold, meaning above the first
threshold 1140 or
below the second threshold 1142 in step 1160, step 1164 determines the
wastegate
position gain signal or the wastegate change signal accordingly. It should be
noted that
the thresholds 1140, 1142 may be different distances from the boost set point.
Therefore, step 1160 may be replaced by determining whether the boost is above
the
first boost threshold 1140 or below the set threshold 1142 illustrates in
Figure 11 B.
53
Date Recue/Date Received 2022-01-07
[00218] When the boost error is not greater than the boost error threshold in
step
1160, step 1166 applies less gain which is used in step 1164 to calculate the
wastegate
position gain signal or the wastegate change signal. After step 1164, step
1158 is
again performed to determine the wastegate position that is based upon the
amount of
distance above or below a set point. The amount of wastegate position change
may be
directly calculated based upon the boost pressure amount above or below a
boost set
point.
Thereafter, step 1170 the wastegate position is changed based upon the
wastegate position change signal.
Ultimately, this system continually repeats to
reposition the wastegate based upon the various sensors.
[00219] Referring now to Figure 12A, turbocharged two-stroke engines create
substantially more power in higher elevations than naturally aspirated
snowmobile
engines which leads to a more difficult operating experience because the power
delivery
may be too much for an unskilled operator. Aftermarket turbocharger kits are
difficult to
handle in challenging situations.
Riders of different skill levels desire different
performance characteristics so they do not feel overwhelmed. In the following
example,
the controller 910 of Figure 9A is illustrated in further detail. For
simplicity sake, the
sensors 912-918, 734, 937, 939 , 935 , 939A,939B, 939C, and 939D are not set
forth
but are incorporated by reference. In this example, an user interface 1212 is
shown as
a switch 1214 that has various positions such as an off position, a sport
position, a
performance position and a race position. Of course, those skilled in the art
will
recognize that the names and the number of selectable features may be varied.
In
addition, a touch screen user interface 1216 is illustrated. The touch screen
user
interface 1216 includes touch screen button 1218A that corresponds to a sport
mode,
54
Date Recue/Date Received 2022-01-07
touch screen button 1218B that corresponds to a performance mode and touch
screen
button 1218C that corresponds to a race mode. Of course, the touch screen
interface
may also include physcial buttons 1220A-1220C that correspond to the sport,
performance and race modes, respectively. Further, a spearate "off" button may
be
provided. Of couse a second selection of the touch screen buttons 1218A-C or
physical
buttons 1220A-C may turn the particular mode off. As mentioned above, the
wording
or descriptors of the various modes and the number of modes may change. Also,
in a
constructed example, one of the switch 1214, the touch screen user interface
1216 or
the physcial buttons 1220A-1220C may be provided.
[00220] The user interface 1212 is coupled to the controller 910 through a
controller area network 1222. The controller area network communicates the
signals
corresponding to the switches that provides a mode signal to the controller
910.
[00221] The controller 910 includes an idle module 1230 that determines
whether
the vehicle is idling. The idle module communicates signals to a boost filter
module
1232. A boost set point module 1234 and a scale module 1236 communicates
signals
to the boost target module 1238. The boost target module 1238 communicates a
signal
to the boost error module 1240 which, in turn, receives signals from the boost
filter
module 1232. An overtemperature module 1242 may also be included within the
controller 910. The overtemperature module 1242 provides correction for the
condition
where overtemperature is determined. An overboost module 1244 provides the
controller 910 with a correciton for overboost.
[00222] Referring now to Figure 12B, a method for controlling the system
according to the user selectable interface is set forth. In step 1250, the
barometric
Date Recue/Date Received 2022-01-07
pressure is determined. In step 1251, the base target boost pressure is
determined. In
step 1252, it is determined whether an interlock is engaged. When an interlock
is
engaged in step 1252, step 1250 is again performed. The interlocks are set
forth in
steps 1253A-1253F. Various types of interlocks may prevent the user interface
selection from being used to control the vehicle. For example, 1253A allows a
limited
ability user lock to be enabled. The limited ability user lock may be enabled
by the user
interface menus in which a limited ability user lock inteface code or password
may be
set. Without knowing the password, the lmited ability lock may prevent the
system from
using the user selectable modes. The limited ability user lock may also be
referred to
as a child lock. A password protection may also be provided in step 1253B.
When a
password is provided, the boost modes may not be selectable. Such a condition
is
suitable for the rental market in which certain modes may not be desirable for
various
users. In step 1253C, whether the throttle position sensor is generating a
signal
greater than the throttle position sensor interlock threshold is determined.
That is, when
the throttle position is high, meaning the throttle position is opened past an
idle state or
other threshold, the throttle position interlock threshold may prevent the
system from
being scaled according to the user interface. Likewise, in step 1253D, when
the vehicle
speed is greater than a vehicle speed interlock threshold, the scaling of the
boost
modes may not be performed. in step 1253E, the time may also be a factor for
interlocking the system. That is, when the time is less than a time interlock
threshold,
the system may not allow for the user boost to be changed. In a similar
manner, step
1253 prevents the user boost mode from activating when the absolute manifold
pressure is greater than a pressure threshold. When at least one of the steps
1253A-
56
Date Recue/Date Received 2022-01-07
1253F are true, the interlock is engaged. When the interlock is not engaged in
step
1252, step 1254 receives a boost mode selection. As illustrated in Figure 12A,
the
controller area network may provide the selection signal from the user
interface. A
boost mode scale factor is set in step 1255 according to the selection signal.
In step
1256, the target boost mode based upon the target boost and the boost modle
scale
factor is determined. In step 1257, the target boost correction is performed.
The
exhaust bypass valve is controlled based upon the target boost in step 1258.
[00223] Referring now to Figure 12C, further details of the method for
operating is
set forth. In this example, the barometric pressure is determined in step
1262A, the
engine speed is determined in step 1262B and the throttle position sensor
signal that
corresponds to the throttle position is determined in step 1262C. The throttle
position is
used to determine whether the idle mode is engaged. In step 1264, it is
determined
whether the idle modle entry conditions are determined based upon the engine
speed
from step 1262B and the throttle position from step 1262C. After step 1264,
step 1265
sets the parameter "Kboost" to 0 indicating the system is at idle mode. Kboost
is
determined once at startup and cleared when the engine is shut down.
[00224] In step 1266, determines the boost mode that is selected by the user
interface. The user selection from step 1266, the throttle position from step
1262C and
the engine speed from step 1262B are provided through the controller area
network
1222. The scaling factor from the sport module 1268A, the performance module
1268B
or the race module 1268C is provided to a boost scaling step 1270. The boost
target
base is determined in step 1271. The boost set point is determined in step
1272. The
boost set point of step 1272 is determined from the boost target base in step
1271
57
Date Recue/Date Received 2022-01-07
which is determined from the barometric pressure from step 1262A and the
engine
speed from step 1262B. Of course, other factors described below may be used to
change the boost target base. Utlimately, the boost scaling from step 1270 and
the
boost set point from step 1272 are combined in step 1273 and ultimately used
to
determine the boost target in step 1274. The vehicle is controlled using the
boost target
determined in step 1274.
[00225] Referring back to step 1265, the boost pressure readings in step 1276
are
zeroed based upon three consecutive raw boost determinations. The boost
pressure
for idle uses the raw boost with the Kboost determined in step 1276. The boost
pressure from step 1277 is used by step 1278 to determine the boost filter
value. The
boost filter value in this example uses a number of sample values from step
1277. In
step 1279, the number of values used in step 1278 is provided. A differential
block
1280 receives the filtered boost pressure and the target boost pressure in
step 1274 to
determine a boost pressure error in step 1281. The difference between the
boost target
pressure of step 1274 and the boost filter value of step 1278 that is
calculated versus
the scale boost value determines the boost error in step 1281.
[00226] It should be noted that when the boost scaling is performed in step
1270,
the amount of scaling varies depending upon the user's selections. The amount
of
scaling may, for example, take place as a percentage of the set point.
[00227] Referring now to Figure 13A, the operation of the overboost modu1e1244
of Figure 12A is set forth. In Figures 13A and 13B, the control of the engine
to prevent
overboost or high post-compressor temperatures is set forth. This allows the
engine to
be protected without being very intrusive. That is, abrupt changes in the
boost level are
58
Date Recue/Date Received 2022-01-07
avoided. The low inertia and low weight of a snow vehicle is significantly
impacted by
the amount of power delivery of the engine. Abrupt changes in the amount of
power
provided leads to a feeling of instability and may ultimately lead to the
vehicle being
stuck.
[00228] In step 1310, the target boost is determined. As mentioned above, the
target boost may be determined as described in reference to Figures 12B and
12C. In
step 1312, the actual boost pressure is measured by a pressure sensor. In step
1314,
when the boost pressure is greater than the target boost multipled by a first
overboost
factor, step 1316 is performed. When the boost pressure is not greater than
the target
boost with the overboost factor, step 1312 is performed. The overboost factor
is a
predetermined amount that is calibratable by the system designer. The
overboost factor
is a numeric factor that allows the boost pressure to exceed the target boost
by a
predetermined amount. The overboost factor may be greater than one so that the
target boost may be exceeded by a predetermined amount or percentage.
[00229] In step 1316, a timer is started. When the timer is greater than a
first
threshold in step 1318, step 1320 positions the wastegate to a calbriatable
position in
step 1320. In step 1322, a calibratable time delay is waited.
[00230] In step 1324, if the boost pressure is not greater than the target
boost with
the overboost factor, step 1310 is again performed. In step 1324 when the
boost
pressure is greater than the target boost multiplied by a second overboost
factor, step
1326 resets the timer and initiates the second timing process. The second
overboost
factor may be different than the first overboost factor of step 1314. In step
1328, if the
timer is greater than a second timer threshold, step 1330 changes the position
of the
59
Date Recue/Date Received 2022-01-07
exhaust bypass valve or wastegate. The timer in step 1316 and 1326 allow a
predetermined amount of time to pass before the values are changed. In step
1330, the
amount of opening of the exhaust bypass valve or wastegate is changed. This
may
vary depending upon the difference between the boost pressure and the target
boost or
the target boost with the overboost factor. In step 1332, an overboost warning
may be
provided after the second attempt to change the boost pressure. The time delay
in step
1322 and step 1326 is calibratable so that the air flow to the engine and
therefore the
power output of the engine has enough time to show some change. This allows
the
engine to be protected without being intrusive to the rider or leaving the
rider stranded.
[00231] Referring now to Figure 13B, a method for operating the
overtemperature
module 1242 of Figure 12A is set forth. In this example, the target boost is
determined
in step 1340. In step 1342, the maximum post compressor temperature as a
function of
the target boost is determined.
This may be a calibated factor determined duriing
development that may provided in a lookup table. In step 1344, the actual post
compressor temperature is determined. The post compressor temperature may be
determined by the post compressor temperature sensor 939D illustrated in
Figure9A.
In step 1346, the actual post compressor temperature is compared to the
maximum
post compressor temperature threshold. When the actual post compressor
temperature
is not greater than the maximum post compressor temperature threshold, step
1340 is
again performed. In step 1346, when the actual post compressor temperataure is
greater than the maximum post compressor temperature threshold, step 1348 is
performed in which a timer is started. In step 1350, the timer value is
compared to a
first time threshold. When the timer is greater than the first time threshold
in step 1350,
Date Recue/Date Received 2022-01-07
step 1352 reduces the target boost and resets the timer in step 1354. A
counter is
incremented in step 1356. When the counter is not greater than a counter
threshold,
step 1346 is again performed. In step 1358, when the counter is greater than
the
counter threshold, step 1360 commands the wastegate to a calibratable
position. In
step 1362, the electronically controlled engine exhaust valve or valves on a
multicylinder engine is commanded to a calibratable position.
In step 1364, an
overtemperature warning is generated. The overtemperature warning may be an
indicator light provided on the display of the vehicle. In the foregoing
example, the first
response loop continues for the calibratable number of loops and can
continuously drop
the target boost pressure until either the post compressor temperature drops
below the
above mentioned calibratable limit or the loop count reaches a calibratable
value.
When the loop count reaches the calibratable value, the system enters a second
state
of response in which the wastegate valve is commanded to a calibratable
position and
the exhaust valves of the engine are commanded to a calibratable position to
protect
the engine.
[00232] Referring now to Figure 14A, a method for controlling the wastegate
during deceleration of the vehicle is set forth. In the following example, the
wastegate
position is moved based upon the throttle position or the rate of change of
the throttle or
both. The method purposely opens the wastegate prior to a condition of
overboost and
may more fully open the wastegate than in an overboost condition as described
above
in Figure 13A. This allows the overboost condition to be reduced and prevents
poor
scavenging through the engine that is caused by high exhaust pressure. Poor
scavenging causes poor running quality and possible knock or denotation, or
hesitation.
61
Date Recue/Date Received 2022-01-07
[00233] In step 1410, the throttle position is determined, in step 1420, the
rate of
change of the throttle position is determined. In step 1422, the engine speed
is
determined. A boost level is determined in step 1424.
The boost level may be
determined in various ways including that set forth in Figures 12A-12C. In
step 1426,
the commanded wastegate position is determined based upon the engine speed and
the boost level. In step 1428, a correction factor is determined based on the
throttle
arate of change or the throttle position
[00234] In Figure 14B, the wastegate opens slightly based on an overboost
condition in the region set forth in the area circled by the area 1440. The
area 1440
circled is the throttle position sensor signal 1442. The engine speed is
signal 1444 and
the boost pressure is 1446. The wastegate actuator position is signal 1448. In
Figure
14C, the wastegate actuator position illustrated by signal 1448 is purposely
driven to
more fully open based upon the declining engine speed represented by the
signal 1444.
As can be seen by contrasting Figures 14B and 14C, the boost pressure 1446
does not
obtain such a high level as that illustrated in Figure 14B.
[00235] Referring now to Figure 15A, one drawback to turbocharged snowmobiles
is the time delay associated with the turbocharger building boost for the
engine to
accelerate. The use of a bypass control wastegate creates a parallel path from
the
tuned pipe to the silencer that allows for significant improvements in the off
boost
engine speed response. However, under very fast transients when the pipe
pressure
remains high and the turbocharger speed is low, the engine response requires a
different amount of bypass airflow then it would during a slower transient
response. In
62
Date Recue/Date Received 2022-01-07
the following method, a two-stage specific wastegate control based on the
engine speed
and the boost error are used until the engine has reached a target boost set
point.
[00236] In step 1510, the barometric pressure is determined from a barometric
pressure sensor. In step 1512, the engine speed is generated from an engine
speed
sensor. In step 1514, the throttle position is determined from a throttle
position sensor.
In step 1516, the boost pressure is determined from a boost pressure sensor.
It should
be noted that step 1510 through 1516 are continually performed during the
operation of
the engine. In step 1518, the boost offset of Step 1520 is performed once when
the
engine is in an idle state upon power up of the engine controller (ECU) and
stored
therein. In step 1520, the boost offset is determined in a similar manner to
that
described above. The boost offset is used for zeroing using an average to get
(Kboost).
In step 1522, the boost offset and the raw boost from step 1516 are used
together with
a barometric pressure to determine the boost pressure. That is, the raw boost
with the
offset removed and the barometric pressure removed is used to obtain the boost
pressure. A filtered boost pressure is determined in step 1524 which uses a
number of
boost pressure readings. That is, a number of samples may be averaged for the
boost
pressure reading to obtain the filtered boost pressure reading. In step 1526,
a scale
factor may be determined from the user settings as described above in Figures
12A-
12C. In step 1528, a target boost from the boost scaling is generated. In step
1530, the
boost offset is used to obtain the boost target. The fuel mode may also be
used for
changing the boost target in step 1532. Depending upon the type of fuel, a
lookup table
may be used for determining a fuel mode correction. In step 1534, a detonation
factor
may be used to adjust the boost target. In step 1536, a boost error, which is
the filtered
63
Date Recue/Date Received 2022-01-07
boost minus the target boost, is determined. In step 1538, based upon engine
speed
and the throttle position, a launch mode is determined. Launch mode is
determined
based upon the engine speed and the throttle position. This may be performed
by
referring to a table using a one or zero that defines whether the PID control
of the
wastegate is active at the operating point. In step 1540, it is determined
what the rate of
change of the throttle position sensor is. In step 1542, when the throttle
position rate of
change is greater than a throttle position rate of change threshold, step 1544
is
performed. When the throttle position rate of change is not greater than the
throttle
position rate of change threshold, step 1510 is performed. In step 1544, when
the
launch state is not active, step 1510 is performed. When the launch state is
active, the
fixed position PID control is enabled. This is in contrast to when the boost
error PID
mode is activated. Thus, when the fixed position PID control is activated, the
launch
state is active and step 1546 is performed. Step 1546 determines whether the
boost
pressure is less than the target boost times a scale factor. Thus, when all
three
conditions of steps 1542-1546 are performed, step 1550 enters a first stage of
acceleration mode. The wastegate enters a fixed position PID control stage
that
controls the wastegate position to a desired percentage opened based upon the
engine
speed and the boost error in step 1552. In step 1554, a timer is initiated. In
step 1556,
when the timer period has not expired, step 1556 is again performed. In step
1556,
when the time has expired, step 1558 is performed to determine the target
boost from a
second map based upon the engine speed and boost error. In step 1560, the
boost
pressure is determined. In step 1562, if the boost pressure is below the
target boost
pressure multiplied by a scaling factor, then a second stage PID control mode
is entered
64
Date Recue/Date Received 2022-01-07
in step 1564. The second stage will be activated as long as the condition in
5tep1562 is
true. In the second stage of 1564, step 1566 controls the wastegate to a
calibratable
percentage opened based upon the engine speed and the boost error. A separate
control map different than the control map used in the first stage may be
used. The
control maps are determined during the development process. By implementing
the
multi-stage acceleration function, fast engine and turbocharger response is
created and
thus faster acceleration is achieved. Quicker acceleration for normally
aspirated
engines is achieved during a high rate of transients. The drivability of such
a system in
high-speed throttle drop conditions, which are common in tree riding, is
achieved.
Smoother transitions from a fixed state PID control to a boost pressure PID is
achieved.
The flexibility for acceleration control with distinct maps between stages is
also
achieved. The transition from the second stage boost PID to a target boost
scaling
conditional parameter in the second stage is performed while in the loop. A
reduction in
underboost condition is also achieved with low initial turbocharger speeds.
Referring
now to Figure 15C, the engine speed signal is signal 1570. The throttle
position is
signal 1572. The boost pressure is signal 1574 and the wastegate position is
1576.
The various stages of wastegate control are illustrated. A first region 1578
shows a first
stage control. Region 1580 is controlled by the second stage. Region three is
controlled in a PID mode at 1582.
[00237] Referring now to Figures 16A and 16B, a connecting rod 1610 is
illustrated having a shank 1612 having a first bearing bore 1614 and a second
bearing
bore 1616, the first bearing bore 1614 has a first roller bearing 1618
disposed therein.
Date Recue/Date Received 2022-01-07
A second roller bearing 1620 is disposed in the second bearing bore 1616. A
description of one suitable example of a roller bearing is set forth below.
[00238] The shank 1612 has a first web portion 1622, a second web portion 1624
and a center portion 1626 disposed between the first web portion 1622 and the
second
web portion 1624. As is best illustrated in Figure 16B, the thickness of the
center
portion 1626 is less than the thickness of the first web portion 1622 and the
second web
portion 1624. A first hole 1628A is disposed through the center portion 1626
adjacent to
wall 1630 defining the first bearing bores 1614. A second hole 1628B is
disposed within
the center portion 1626 adjacent to the wall 1632 that defines the second
bearing bore
1616. The holes reduce the stiffness near the bores, which balances the
bearing roller
forces to improve bearing life. Since the stiffness of the connecting rod 1610
at each
end near the bores are difficult to affect with forging geometry changes, a
machined
hole or a plurality of holes after forging allows the desired stiffness to be
achieved. The
reduced stiffness in the shank near the bore balances the bearing roller
forces and
reduces the peak roller force during a compressive load due to distortion of
the bearing
bore. High roller forces in a needle roller bearing used in a connecting rod
of a two-
stroke engine causes spalling as well as overheating of the bearing. The high
roller
forces are due to the connecting rod stiffness preventing it from conforming
to the shape
of the bearing with a necessary clearance, which loads some rollers much more
than
others. The stiffness of the connecting rod in each end of the bore is
difficult to affect
with forging geometry changes. Ultimately, the reduction in stiffness causes
the
bearings to have increased life. The holes also reduce the connecting rod
mass, which
66
Date Recue/Date Received 2022-01-07
is highly desirable. The size and the location of the holes may be changed to
balance
the roller forces and optimize the weight.
[00239] Referring now to Figure 16C, a combustion event having the forces on
the
roller bearing is illustrated. Plot 1650 shows roller forces on a connecting
rod without a
hole. Plot 1652 shows the plot of the roller forces with the holes. The peak
roller force
is thus reduced by marking a comparison and the forces are more balanced
around the
perimeter of the bearing bore.
[00240] Referring now to Figure 16D, a plot of the inertia direction forces
without
the holes illustrated by lines 1654 and with the holes illustrated by lines
1656 are nearly
identical and thus the inertia direction forces are unchanged.
[00241] Referring now to Figure 17, a roller bearing 1710 suitable for use as
roller
bearing 1618 or 1620 of Figure 16A is set forth. The roller bearings 1710 may
be three
dimensionally metal printed in a first half and a second half. The roller
bearing 1710
has a cage 1712 with a plurality of longitudinal extending slots 1714. The
longitudinally
extending slots 1714 do not extend all the way to the furthest width or ends
of the cage
1712. The cage may be printed with the needle rollers 1720 incorporated
therein. This
allows the needle roller 1720 to be encapsulated in the cage with no
additional
processing required. Holes 1722 through the space or longitudinally extending
walls
1724 allow oil to pass through the cage. The cage 1712 may also be printed in
halves
for split rod bearing designs. Hollow sections are used to reduce the weight
of the
bearing with the process. The steel cage 1712 may be thinly coated with copper
or
silver during the printing process to reduce friction on all the surfaces.
This eliminates
the need for further processing or coating of the part after it is formed. As
mentioned
67
Date Recue/Date Received 2022-01-07
above, the needle roller bearing cage 1712 may be used in various locations on
a
vehicle, especially in a two-stroke engines where needle roller bearings are
typically
used.
[00242] In previous roller bearings with stamped bearing cages, the cage was
crimped to encapsulate the rollers. Deformation caused by the process affected
the
roundness of the cage. The present process of three-dimensional printing
reduces the
deformation of the bearing cage. The lubricating holes allow more oil to pass
through
the bearing and increase the life of the bearing.
[00243] Referring now to Figure 18, the controller 910 of Figure 9A is
illustrated
with different modules disposed therein. In this example, the controller 910
is coupled to
various sensors including all of the sensors illustrated in Figure 9A. In this
example, all
of the sensors are not specifically illustrated. The throttle position sensor
918 is
illustrated, the wastegate position sensor 939C, a boost pressure sensor 912,
engine
speed sensor 914, the atmospheric or barometric pressure sensor 916, the tuned
pipe
pressure sensor 734 and other sensors 1810 including the other sensors set
forth in
Figure 9A.
[00244] The controller 910 includes controller 1812, a wastegate initializer
module
1814 a fuel adjustment module 1816 and a sensor diagnostic module 1818. The
exhaust valve controller 1812 controls the position of the electronically
controlled
exhaust valve 49. The wastegate initializer 1814 is used to initialize the
position of the
wastegate to zero out any inconsistencies. The wastegate initializer 1814 may
generate
a screen display such as an indicator light or a display on the touch screen
at the
display 1820. The fuel adjustment module 1816 performs fuel amount adjustments
in
68
Date Recue/Date Received 2022-01-07
response to one or more of the boost pressure, the barometric pressure, the
engine
speed and the throttle position as determined by the sensors.
[00245] The sensor diagnostic module 1818 may generate a service flag 1822 and
generate an indicator on the display 1820. The service flag 1822 may be set
within the
software of the system.
[00246] A memory 1830 stores various parameters and calibratable data therein.
In this example, wastegate values 1832 are stored within the memory. As well,
a table
having boost box pressure and throttle position for determining the position
of an
electronically controlled exhaust valve is set forth in the memory portion
1834. The
modules 1812 through 1818 are described in further detail below.
[00247] Referring now to Figure 19, a method of operating the engine, and in
particular the exhaust valve controller 1812 of Figure 18 is set forth. The
method of
Figure 19 may be performed in engines with or without a turbocharger. In the
following
method, a method for controlling the electronically controlled exhaust valves
of the
engine is set forth. The throttle position and the absolute air box or boost
box pressure
is used to determine the engine speed at which the exhaust valve controller
1812
commands the electronically controlled exhaust valve 49 to move.
[00248] In step 1910, the boost box pressure is determined. The boost box
pressure takes into consideration the turbocharger boost if in a turbocharged
engine
and the barometric pressure, each of which are present within the boost box.
In step
1912, the throttle position is determined. The throttle position is determined
from the
throttle position signal. Typically, the throttle position is a percentage of
the amount that
the throttle is opened. In step 1914, the engine speed from the engine speed
sensor is
69
Date Recue/Date Received 2022-01-07
determined. Typically, the engine speed is a value corresponding to the
rotational speed
of the crankshaft. In step 1916, the boost box pressure signal and the
throttle position
signal are used to determine the engine speed at which to trigger the opening
of the
exhaust valve. In step 1918 when the engine speed reaches the engine speed
trigger or
is greater than the engine speed trigger step 1920 opens the exhaust valve. In
step,
1918 when the engine speed is not greater than the engine speed trigger the
system
repeats in step 1910. As mentioned above, step 1916 uses a two-dimensional
boost
box/throttle position table such as that illustrated in Figure 18 as reference
numeral
1834. By controlling the movement of the electronically controlled exhaust
valve of the
engine based upon the boost box pressure, the varying elevation and how the
engine
runs due to the different barometric pressures is taken into consideration.
Thus, a
smoother and better operating engine is achieved.
[00249] Referring now to Figure 20, a method for checking the wastegate or
exhaust bypass valve is set forth. The wastegate is placed in a parallel flow
path to the
turbocharger and has an upper and lower mechanical stop that are learned for
accurate
control of the wastegate. The lower mechanical stop and upper mechanical stop
are
learned by the controller 910 using the wastegate initializer 1814 described
above.
Essentially, the voltage readings at each stop are learned. The following
method allows
the voltages at each stop to be learned, stored and used during operation and
compared to determine whether the voltages are out of range so that an
indicator may
be generated to the vehicle operator.
[00250] In step 2010, the system determines whether the vehicle has started.
When the vehicle has started, step 2012 determines if the engine speed is
greater than
Date Recue/Date Received 2022-01-07
an exhaust bypass valve position check threshold. When the engine speed is
greater
than an exhaust bypass valve position check threshold step 2016 is performed.
In step
2012 when the engine speed is not greater than the check threshold step 2010
is
repeated. In step 2014, the position of the valve is determined by reading the
throttle
position sensor voltage. In step 2016, the exhaust bypass valve is commanded
to the
upper mechanical stop. In step 2018, the engine speed sensor and throttle
position
sensor are checked if they are less than an idle state threshold. If the
throttle position
value or engine speed value is above the threshold the sensor outputs
continually read
in step 2018. When the throttle position sensor value and engine speed value
are below
the idle state threshold step 2020 stores the voltage value at the upper
electrical stop.
In step 2022 it is determined whether the upper mechanical stop value is
greater than
an upper voltage threshold. Step 2024 generates a warning signal such as an
indicator
or audible signal at the vehicle display. In step 2022 when the upper
mechanical stop
value is not greater than an upper voltage threshold step 2026 commands the
exhaust
bypass valve to a lower mechanical stop. In step 2028 the throttle position
sensor value
is read. That is, the voltage is monitored in step 2028. In step 2030 the
throttle position
sensor value and engine speed sensor value are monitored to determine they are
less
than an idle state threshold. When the values are not below an idle state
threshold step
2028 is again performed. When the throttle position sensor value and engine
speed
value are below the idle state threshold, step 2032 stores the lower
electrical stop
voltage value. After step 2032, step 2034 determines whether the lower
mechanical
stop value is less than a lower voltage threshold. When the lower mechanical
stop value
is not less than the lower mechanical voltage threshold, step 2010 is again
performed.
71
Date Recue/Date Received 2022-01-07
In step 2034 when the lower mechanical stop value is less than a lower voltage
threshold a warning signal is generated in step 2024.
[00251] Referring now to Figure 21, a method for monitoring the current during
startup is set forth. In step 2110 the current during the startup check
performed in
Figure 20 is monitored. When the wastegate or exhaust bypass valve actuator
current is
higher than a high current threshold step 2114 generates a cleaning check
warning. A
high current may be generated when the system is encumbered by snow, ice or
other
debris.
[00252] In step 2112 when the wastegate actuator current or exhaust gas bypass
valve current is not greater than a high threshold the wastegate actuator
current is
compared to a low current threshold in step 2120. When the wastegate current
is not
below a low threshold current step 2110 is again performed. When the wastegate
actuator current is greater than a low current threshold step 2122 causes the
engine
controller 910 to enter a limp home mode and thereafter step 2124 generates a
mechanism error signal and optionally a warning display.
[00253] The methods set forth in Figures 20 and 21 allow the wear to the
wastegate to be monitored which can impact the current consumption of the
actuator
and change the airflow characteristics of the wastegate or exhaust gas bypass
valve
with regard to the control position. The system also allows the interface
between the
electrical actuator output shaft and the wastegate rotating assembly to be
monitored. In
some instances wear can lead to chatter in an otherwise stable system. Ice
buildup or
other debris on the rotating assembly can be monitored. When debris or ice
buildup
occurs, a slow response of the wastegate can cause an overshoot of the system
72
Date Recue/Date Received 2022-01-07
because the system tries to correct for the response time based on the
undershoot.
Corrections in Figure 20 using the voltage, the system may be continually
monitored for
out of range values.
[00254] Referring now to Figure 22, a method for controlling a fuel and
ignition
system for fueling and controlling the timing of ignition of the engine is set
forth. In step
2210 the boost pressure for the engine is determined. In step 2212 the
throttle position
desired for the engine is also determined. In step 2214 the exhaust bypass
valve
position is determined. In step 2216 the fuel ignition amount based upon the
exhaust
bypass valve position is generated. The amount of fuel for the fuel system is
determined
during development of the engine. The fuel and ignition are also a function of
the boost
pressure at the specific throttle position. However, in conjunction with the
exhaust
bypass valve position, the engine speed may be maintained at a more stable
position.
[00255] Referring now to Figure 23, wastegate position signal 2240 is shown
having an abrupt drop which causes the engine speed signal 2242 to rapidly
increase
then decrease. The rapid increase and decrease are shown as well at the boost
pressure signal 2244. The throttle position signal 2246 as can be seen is
maintained in
the region of the wastegate position signal rapidly decreasing. By controlling
the fueling
and the spark the engine RPM may have the upward spike and downward spike
eliminated as illustrated by the dashed line 2248.
[00256] Referring now to Figure 24, the method for diagnosing a turbocharger
system is set forth. In this example, production pressure sensors that are
mass-
produced have various tolerances. The barometric pressure sensor and the boost
pressure sensor may have different readings when exposed to the same
pressures. The
73
Date Recue/Date Received 2022-01-07
present system allows the difference to be set to zero in the control
software. However,
there is also a check for the diagnosing of a sensor failure. The following is
performed at
idle. In step 2408 it is determined whether the engine is at idle state. If
the system is
not step 2408 is performed. If the engine is at idle in step 2408, step 2410
is performed.
In step 2410, the boost pressure after the turbocharger is determined. This is
determined from a boost pressure signal generated from a boost pressure sensor
that is
disposed downstream of the turbocharger compressor. In step 2412, the
barometric
pressure is determined from a barometric pressure sensor that is disposed
before the
turbocharger. In step 2414, a pressure sensor offset value between the
barometric
pressure signal and the boost pressure signal is determined by comparing the
barometric pressure and the boost pressure signal. In step 2416, it is
determined
whether the pressure sensor offset is outside a tolerance. The tolerance may
have a
threshold 2440 and 2442 as illustrated in Figure 25. When the pressure sensor
offset is
outside of the tolerance meaning outside of the sensor acceptable tolerance
range as
defined by thresholds 2440 and 2442, a service flag may be set in the software
in step
2418. Also, a vehicle display is generated in step 2420. One example of a
vehicle
display is that set forth as the display 2450 of Figure 25. A red indicator
may be
generated when the difference between the boost pressure and the barometric
pressure
are outside of the range. It should be noted that the system measures the
boost
pressure and barometric pressure in steps 2410 and 2412 upon startup of the
engine
when no boost pressure from the turbocharger is being generated. In this state
both the
boost pressure and the barometric pressure should be identical. The engine may
be
allowed to operate in a limited manner in a limp home mode to allow the
vehicle
74
Date Recue/Date Received 2022-01-07
operator to seek help. When the offset is within the range, the boost pressure
is
corrected by the offset value and the engine operates using corrected boost
pressure in
step 2422. After step 2422, the method restarts in 2408.
[00257] The foregoing description has been provided for purposes of
illustration
and description. It is not intended to be exhaustive or to limit the
disclosure. Individual
elements or features of a particular example are generally not limited to that
particular
example, but, where applicable, are interchangeable and can be used in a
selected
example, even if not specifically shown or described. The same may also be
varied in
many ways. Such variations are not to be regarded as a departure from the
disclosure,
and all such modifications are intended to be included within the scope of the
disclosure.
Date Recue/Date Received 2022-01-07
