Note: Descriptions are shown in the official language in which they were submitted.
CA 02879253 2016-04-21
Hybrid Split Cycle Internal Combustion Engine
Field of Invention
The invention relates to a hybrid engine between two devices: a single
cylinder 2 stroke pump and a single cylinder 2 stroke 4 cycle internal
combustion engine. The invention also relates to 5 cycles instead of the
conventional 4 cycles of internal combustion and a novel method of
subdividing 4 of the 5 cycles into stages and the use of a redesigned cylinder
heads, a redesigned crankshaft and corresponding camshaft to allocate these
stages to be performed in either the pump cylinder and/or the engine
cylinder. The invention is expected to run in spark ignition or compression
ignition mode.
The invention also relates to 2-stroke and 4-stroke internal combustion
engines.
For the rest of this document, the invention is referred to as the Hybrid
Engine.
Background
Internal Combustion Engine Sub-Assemblies
Generally two or three sub-assemblies make up an internal combustion
engine: Shown in Figure 1 is a cylinder head sub-assembly (A), a cylinder
block (B) and a crankcase block (C) of a 4 stroke split cycle internal
combustion engine. The crankcase houses a crankshaft (19) with at least one
crank throw (18). The cylinder block houses at least one cylinder bore (5 &
13). One end of the bore is covered by a cap known in the industry as the
cylinder head. The cylinder bore houses at least one piston (3 & 11) with
compression rings around it. The top of the piston, known as the crown, the
walls of the cylinder and the cylinder head defines a space in the cylinder
known as the combustion chamber (16). A rod (17) connecting the piston to
1
CA 02879253 2016-04-21
the crank throw (18) enables the mechanical conversion of the lateral up and
down stroke of the expansion piston (11) into 360 degree circular motion of
the crankshaft (19) which in turn causes the up and down movement of the
compression piston (4).
Four Cycles of Internal Combustion Engine
Four steps or cycles govern the operation of an internal combustion engine.
1. Mixture of air and fuel is delivered inside a chamber or cylinder, then
2. Compressed, then
3. Made to combust inside the combustion chamber, then
4. Smoke and other combustion by-products are exhausted from the
combustion chamber.
They are known in the industry as intake, compression, combustion and
exhaust cycles.
Strokes and Cycles
The boundary and duration of a stroke is conventionally defined by the top
and bottom spots where the piston reverses directions in its up and down or
left and right travel inside the cylinder. These are respectively known in the
industry as top dead center (TDC) and bottom dead center (BDC).
The conventional 4 stroke internal combustion design has one cylinder head
sub-assembly consisting of valves, camshafts, belts and gears. One stroke is
assigned to each of the 4 cycles and 4 strokes are required to turn a
crankshaft one complete revolution.
The conventional 2 stroke internal combustion design does not have a
cylinder head. It has exhaust and intake ports in the cylinder wall Instead of
intake and exhaust valves. This arrangement allows it to combine the intake
and compression cycles in one stroke and combustion and exhaust cycles in
another. With no cylinder head, 2-stroke engine turns its crankshaft one
complete revolution in 2 strokes of its piston. The light small footprint
2
CA 02879253 2016-04-21
makes it the engine of choice in motorcycles, garden tools, lawnmowers and
motor boats where small housing is a definite advantage.
Ignition and Fuels
In addition to strokes and cycles, internal combustion engines are classified
based on the type of fuel and the type of combustion. Spark ignition in 4
stroke internal combustion engines are mostly found in motorcycles, cars
and aircrafts which use gasoline or kerosene as fuel.
Buses, trucks,
locomotives stationary generating plants and large marine engines use the 2
stroke internal combustion design to provide high compression ignition of
diesel fuel.
Scavenging - Exhaust Gas Out, Fresh Air In
Scavenging is the process of pushing exhausted gas-charge out of the
combustion chamber and drawing in a fresh draught of air or air/fuel mixture
for the next cycle.
In a 4 stroke internal combustion engine, this is
accomplished using 2 strokes, the exhaust stroke and the intake stroke
respectively. In a 2 stroke internal combustion engine the exhaust cycle and
the intake cycle overlap when both the intake and exhaust ports are open.
This generally results in a small but not so insignificant amount of unburned
air/fuel escaping out into the atmosphere. Small 2 stroke internal
combustion engines using a mixture of gasoline and crank case oil for fuel
and lubrication, which produces exhaust gases containing higher amount of
unburned hydrocarbons. This type of 2 stroke scavenging is expensive and
injures the environment.
Attached Auxiliary Devices
A high engine temperature from combustion and friction between moving
metallic parts must be maintained below a specific threshold to minimize
engine wear and tear and to keep the engine running efficiently. Driven by
the engine's crankshaft, the 4 stroke internal combustion engine employs
auxiliary devices like fans and pumps to circulate air, oil and water around
the engine block.
3
CA 02879253 2016-04-21
To help improve the engine's efficiency and power, modern internal
combustion engines use exhaust gas in turbo charger and exhaust gas
recirculation valve. Driven the engine's exhaust gas a turbo charger is a
turbine that forces extra air into the combustion chamber. As the name
suggests, the exhaust gas recirculation valve re-circulates some of the hot
exhaust gas back into the combustion chamber.
The two-stroke engine with compression ignition is also favored in large
marine engines and stationary power-generating plants that require
dependable long hours of continuous operation. The use of diesel fuel to
reduce operating costs is also a factor. The 4 stroke 4 cycle spark ignition
design using gasoline for fuel is none the less used in in cars and aircrafts.
Air cooled small 2 stroke internal combustion engines in motorcycles, motor
boats and the home and garden appliances do not use auxiliary devices.
Split Cycle Internal Combustion Engine
The split cycle 4 stroke internal combustion engine divides the four internal
combustion cycles into two groups of two cycles and assigns each group to
an expansion cylinder and a compression cylinder. The split cycle engine has
a cylinder head with camshaft and uses 2 strokes of the expansion piston and
2 strokes of the compression piston simultaneously for a combined total of 4
strokes. Similar to a conventional 2 stroke internal combustion engine, a
split cycle engine turns the crankshaft in 2 strokes, 50% more efficient than
the conventional 4 stroke internal combustion engine. A four, six or eight
cylinder split cycle 4 stroke internal combustion spark ignition engine will
require 50% less fuel injectors and 50% fewer spark plugs than their
conventional 4 stroke internal combustion spark ignition engine having an
equal number of cylinders.
Dugald Clerk Engine, the first Supercharger
Development of the internal combustion engine dates back to 1800. A
patent was rewarded to the Otto 4 stoke 4 cycle of internal combustion. In
4
CA 02879253 2016-04-21
getting around the Otto patent, Dugald Clerk developed a 2 stoke equivalent.
There is no record of a patent rewarded to Dugald Clerk or the Clerk cycle.
From the Wikipedia:
"Clerk's engine was made of two cylinders ¨ one working cylinder and an
additional cylinder to charge the cylinder, expelling the exhaust through a
port uncovered by the piston. Some sources consider this additional
cylinder the world's first supercharger. Clerk himself states that "It is not
a
compressing pump, and is not intended to compress before introduction
into the motor, but merely to exercise force enough to pass the gases
through the lift valve into the motor cylinder, and there displace the burnt
gases, discharging them into the exhaust pipe." Hence sources recognise
it instead as a "pumping cylinder", pointing out that it did not actually
compress the fuel-air mixture, it simply moved the fresh mixture to the
working cylinder to force out the gasses burnt previously
Dugald Clerk describes a Cambell engine as using his cycle, as follows: "It
has two cylinders, respectively pump and motor, driven from cranks
placed at almost right angles to each other, the pump crank leading. The
pump takes in a charge of gas and air, and the motor piston overruns a
port in the side of the cylinder at the out-end of its stroke to discharge the
exhaust gases. When the pressure in the motor cylinder has fallen to
atmosphere, the pump forces its charge into the back cover of the motor
cylinder through a check valve, displacing before it the products of
combustion through an exhaust port; the motor piston then returns,
compressing the contents of the cylinder into the compression space. The
charge is then fired and the piston performs its working stroke. This is the
Clerk cycle."
Typical Split Cycle Configuration
Figure 1 shows a cylinder head block (A), cylinder block (B) and crank case
(C)
configuration of a typical split cycle engine. The cylinder block (A) in the
5
CA 02879253 2016-04-21
split-cycle internal combustion engine has two cylinder bores (5 &13) and
corresponding cylinder head sub-assemblies. One set of bore and cylinder
head sub-assembly is for an expansion cylinder (5) and another for a
compression cylinder (13). The two cylinder head sub-assemblies have a
passageway (15) connection controlled by a pressure check valve (6) and an
outlet valve (7). The 4 cycles of internal combustion are split between the
two cylinders.
Starting with the passageway control valve (7) in closed position, the two
cylinders are uncoupled. The exhaust valve (8) of the expansion cylinder is
closed and the intake valve (1) of the compression cylinder is open. From the
previous combustion cycle, the expansion piston (11) is pushed down by the
expanding hot gas turning the crankshaft. The compression cylinder (5) goes
into intake cycle as the compression piston (3) is pulled down by circular
motion of its crank throw, admitting air from the atmosphere and fuel from a
fuel delivery sub-system. When the compression piston (3) reaches the
bottom dead center (4) the intake valve (1) closes, the compression piston
(5) reverses direction; it goes into the compression cycle putting the intake
air/fuel mixture under pressure. As the expansion piston (11) reaches the
bottom dead center (12), the exhaust valve (8) opens and the expansion
piston (11) reverses direction; the expansion cylinder (13) goes into the
exhaust cycle, the expansion piston (11) pushes the exhaust gas out of the
cylinder. The intake valve (1) stays closed. At a preset time shortly before
the compression piston (3) reaches top dead center (2), the exhaust valve (8)
closes, the passageway control valve (6) opens and the pre-compressed
air/fuel mixture in the compression cylinder (5) transfers to the expansion
cylinder (13). The passageway control valve (7) closes and the pre-
compressed air/fuel mixture is ignited. The expansion cylinder (13) goes into
combustion cycle. The cycle repeats.
The Scuderi engine US patents US6543225, US6609371, US6722127,
US6880502, US6952923, US6966329, US7017536, US7121236, US7588001,
US7628126, US7810459, US7954461,US7954463,
US8006656,
US20110220075, US20110220077, of the Scuderi Group is the most recent
6
CA 02879253 2016-04-21
example of previous description of a 4 stroke split cycle internal combustion
engine design.
Referring to Figure 1, a Scuderi engine is shown near the end of the exhaust
stroke; the pressure check valves (6) and outlet valve (7) separating the
compression cylinder (5) from the expansion cylinder (13 ) are closed and the
expansion piston (11) is nearing its top dead center (9) leading the
compression piston (3) still in the compression stroke. Before all the pre-
compressed air/fuel mixture is completely transferred from the compression
cylinder (5) into, and confined in, the combustion chamber (10) of the
expansion cylinder (13), the expansion piston (11) will be way past the top
dead center (9) and would already have reversed direction towards its
bottom dead center (12). Igniting the spark plug (14) before the expansion
piston (11) reaches top dead center (9) will not result in the desired
combustion.
This explains the ignition taking place after the expansion piston (11) is
past
top dead center (9). This is contrary to the conventionally accepted and
decade old practice in spark ignition engines of firing the spark plug a few
degrees before the piston reaches top dead center. Ignition after top dead
center is highly unusual and a probable cause for concern at high engine
RPM.
Why Hybrid Engine
Recent increases in the world oil and gas supply encouraged the continued
used of the internal combustion as the primary source of power in the
transportation industry. At the same time, public awareness of the negative
impact of internal combustion technology on the environment has
increased.
The majority of cars and trucks on the road today run on a 4 stroke 4 cycle 4
cylinder internal combustion engines.
A 4 cylinder Hybrid Engine is
expected to have the same or smaller carbon and physical foot print.
7
CA 02879253 2016-04-21
The Hybrid Engine can be manufactured using the same environmentally
friendly technologies and manufacturing facilities used for making the 4
cylinder 4 cycle 4 stroke engine.
The less costly Hybrid Engine requires fewer parts (50% less spark plug, 50%
less fuel injector and 25% less valve), turns its crankshaft in 50% fewer
strokes (2 stroke of the pump piston and 2 strokes of the engine piston
happening simultaneously).
Because of these characteristics the Hybrid Engine can be expected to be
more fuel efficient and financially and environmentally friendly.
Brief Description of the Drawings
Figure 1 ¨ Example of Scuderi Split Cycle 4 Stroke Engine at Exhaust Stroke
Figure 2 ¨ Example Embodiment of the Hybrid Engine (Using 67.5 degrees
Crank Throw Angle)
Figure 3 ¨ Example Embodiment of the Hybrid Engine (Using 45 degrees
Crank Throw Angle)
Figure 4 ¨ Example Embodiment of the Hybrid Engine (Using 90 degrees
Crank Throw Angle)
Figure 5 ¨ 67.5 Degrees Crank Throw Positions at the Start of the Final
Compression Stage
Figure 6 ¨ 45 Degrees Crank Throw Positions at the Start of the Final
Compression Stage
Figure 7 ¨ 90 Degrees Crank Throw Positions at the Start of the Final
Compression Stage
Figure 8 ¨ Compression Valve Stem Seal
Figure 9 ¨ Compression Plate
8
CA 02879253 2016-04-21
Figure 10 ¨ Early Air Intake Stage and Final Compression Stage
Figure 11 ¨ Final Air Intake Stage and Start of Combustion
Figure 12 ¨ Early Exhaust Stage and Early Air Transfer Stage
Figure 13 ¨ Middle Exhaust Stage and Middle Air Transfer Stage
Figure 14 ¨ Final Exhaust Stage and Middle Air Transfer Stage
Figure 15 ¨ Early Compression Stage and Final Air Transfer Stage
Brief Description of the Tables
Table 1¨ Stages, Piston Directions and Valve Controls Using 67.5 Degrees
Crank Throw Angle (refer to Figure 5 for Pump and Engine Crank
Throws Positions)
Table 2 ¨ Stages, Piston Directions and Valve Controls Using 45 Degrees
Crank Throw Angle (refer to Figure 6 for Pump and Engine Crank
Throws Positions)
Table 3 ¨ Stages, Piston Directions and Valve Controls Using 67.5 Degrees
Crank Throw Angle (refer to Figure 7 for Pump and Engine Crank
Throws Positions)
Table 4 ¨ Effect of Different Crank Throw Angles on Early
Compression Stage and Final Compression Stage
Detailed Description of the Hybrid Engine
The Clerk engine, Scuderi engine and the Hybrid Engine in this invention, all
have two cylinders one of which is the power, engine or expansion cylinder
where combustion takes place. The second cylinder in the Scuderi engine
9
CA 02879253 2016-04-21
compresses the intake air; in the Clerk engine, it is a simple pump. In the
Hybrid Engine the second cylinder serves as both a pump and a compressor
hence it has a special compressor seal around the stem of its compression
valve.
The expansion crank throw in the Scuderi engine leads the compression
crank throw and the spark plug fires on or after top dead center. In the Clerk
and the Hybrid Engines, it is the reverse and the spark plug fires before top
dead center.
Both the Hybrid Engine and the Scuderi engine have cylinder heads with
intake and exhaust valves and an air passageway in place of the intake and
exhaust ports in the cylinder walls of the Clerk engine. To manage the flow
of air between cylinders the Hybrid Engine relies solely on the cylinder head
valves, making the pressure control valve unnecessary.
Ordinarily during the exhaust cycle, exhaust gas is simply pushed by the
engine piston out of the engine cylinder. Both valves of the 2 stroke engine
of the Hybrid Engine are simultaneously open during part of the exhaust
cycle. The same is true in the Clerk engine but not for the Scuderi engine.
Pushed by the pump piston in the Hybrid Engine, the cooler, dense intake air
from the pump cylinder displaces the bulk of hot, less dense exhaust gas
from the engine cylinder. In this process, some residual exhaust gas remains
and gets re-cycled, possibly eliminating the need for an exhaust gas re-
circulating valve mentioned in the Background.
Similar to current 4 stroke spark ignition internal combustion engines, the
Hybrid Engine uses a fuel injector for fuel delivery during the compression
cycle which prevents unburned air/fuel mixture from escaping into the
atmosphere.
Novelty Features of the Hybrid Engine
The major properties that make the Hybrid Engine unique are:
CA 02879253 2016-04-21
1. It designates one cylinder as the 2 stroke engine and the second cylinder
as a 2 stroke air pump that supplies the engine with a reliable flow of air
from the atmosphere for scavenging. But unlike the Clerk and the
Scuderi engines, the Hybrid Engine's pump cylinder also works in
conjunction with the engine cylinder during part of the intake, part of
the compression cycle and part of the exhaust cycle.
2. The Hybrid Engine uses 5 cycles instead of the conventional 4 cycles of
internal combustion:
a. The conventional intake cycle is renamed air intake cycle when the
pump cylinder admits air from the atmosphere.
b. A new air transfer cycle is inserted between the conventional intake
cycle and the compression cycle. This cycle moves intake air from the
pump cylinder into the engine cylinder. Fuel is delivered during the
air transfer cycle and/or compression cycle.
c. Compression, combustion and exhaust cycles complete the Hybrid
Engine's 5 cycles of internal combustion.
3. The Hybrid Engine splits the 5 cycles of internal combustion into smaller
stages.
4. The equal arc subdivisions of the 360 degree circumference of
crankshaft revolution define the opening and closing of the intake,
compression and exhaust valves.
5. The crank throw assignment to the pump piston and engine piston with
the pump piston in the lead, it arrives at its dead centers ahead of the
engine piston.
6. The compression seal around the stem of the compression valve has not
been used in other engines.
7. The volume capacity of the pump cylinder is equal to or greater than the
volume capacity of the engine cylinder,
8. The optional compression plate is sandwiched between the engine
cylinder head sub-assembly and the engine cylinder block.
The values assigned to the arc and crank throw angle determine the
characteristics of the Hybrid Engine.
11
CA 02879253 2016-04-21
The above features are expanded upon below.
Cylinder Designation
The Hybrid Engine uses the secondary cylinder as an auxiliary air pump
device. Like the fans, oil and water pumps the attached or embedded 2
stroke air pump is essential for the successful and continued running of the 2
stroke engine.
Splitting of 360 Degrees into Arcs and Stage of Five Internal Combustion
Cycles
Conventional internal combustion engines define the down stroke of the
piston inside the cylinder to begin at the top dead center (TDC) and ends at
the bottom dead center (BDC). The up stroke does the opposite. The timing
and duration of the intake, compression, combustion and exhaust cycles
directly correlate to the position of the piston being at or very close to TDC
or
BDC.
The 5 cycles of the Hybrid Engine's internal combustion is shown in Tables 1,
2 and 3. During the air intake cycle the pump cylinder admits air from the
atmosphere. This cycle is divided into early an air intake stage and a final
air
intake stage. The air transfer cycle is inserted between the air intake cycle
and the compression cycle. This new cycle is divided into an early an air
transfer stage, a middle air transfer stage and a final air transfer stage
when
intake air is transferred from the pump cylinder into the engine cylinder. The
compression cycle is divided into an early compression stage and a final
compression stage. The combustion cycle remains intact as one stage. The
exhaust cycle is divided into an early exhaust stage and a final exhaust
stage.
Shown in Figures 5, 6 and 7, the Hybrid Engine subdivides the 360 degree
rotation of the crank throw into at least 16 equal arcs. The arcs are 0 to 1,
1
to 2, 3 to 4, 4 to 5, 5 to 6, 6 to 7, 7 to 8, 8 to 9, 9 to 10, 10 to 11, 11 to
12, 12
to 13, 13 to 14, 14 to 15 and 15 to 0. Timing and duration of the stages are
defined using the arc which the crank throw is pointing at and accordingly
12
CA 02879253 2016-04-21
the valves are set to open or close positions as required for the execution of
a specific stage of the cycle.
Tables 1, 2 and 3, in addition to the cycles and stages, show the pistons'
direction, the valves positions and the arcs the crank throws point to at
different stages. The following is a detailed description of the Hybrid
Engine's operation.
1. Illustrated in Figure 10, the Hybrid Engine assigns the early air intake
stage to the pump cylinder (8) and the final compression stage of the
compression cycle to the engine cylinder (18). The pump intake valve
(2) is open, the engine compression valve (10) is closed and the engine
exhaust valve (12) is closed. The pump piston (6) moves down admitting
air from the atmosphere and the engine piston (16) moves up
compressing the air/fuel mixture in the engine cylinder (18). When the
engine piston reaches X degrees before TDC, a spark plug ignites
initiating combustion of compressed air/fuel mixture.
2. Illustrated in Figure 11, the Hybrid Engine assigns the combustion cycle
to the engine cylinder and the final air intake stage of the intake cycle to
the pump cylinder (8). The pump intake valve (2) is open, the engine
compression valve (10) is closed and the engine exhaust valve (12)
closes. The pump piston (6) moves down and the engine piston (16)
moves down. When the pump crank throw (26) reaches arc 8 to 9, the
intake valve (2) closes and the pump piston (6) reverses direction and
begins to move up.
3. Illustrated in Figure 12, the Hybrid Engine assigns the early exhaust
stage to the engine cylinder (18) when the pump intake valve (2) is
closed, the engine compression valve (10) closed and the engine crank
throw reaches arc 6 to 7. The pressure in the engine cylinder is higher
that the atmospheric pressure. The exhaust valve (12) opens and the
hot exhaust gas escapes out the exhaust port (13). The engine piston
(16) continues moving down and the pump piston (6) continues moving
up. With the engine compression valve (10) in a closed position, the
pump piston (6) exerts pressure on the intake air in pump cylinder (8).
13
CA 02879253 2016-04-21
4. Illustrated in Figure 13, the Hybrid Engine assigns the middle air
transfer stage and the middle exhaust stage to both pump cylinder (8)
and engine cylinder (18). When the engine crank throw (27) reaches arc
7 to 8, the engine compression valve (10) opens. Due to the higher
cylinder (8) pressure, air blows into the engine cylinder (18). The
blowing action lowers the temperature inside the engine cylinder (18)
and forces more gas out the exhaust port (11). The two cylinders go into
the early air transfer and middle exhaust stages. The engine piston (16)
continues moving down. After the pump crank throw (26) passes arc 10
to 11, the middle air transfer stage begins. The pump piston (6)
continues moving up pushing the intake air from the pump cylinder (8)
into the engine cylinder (18). The hot exhaust gas directly below the
engine compression valve (10) is displaced. The exhaust gas directly
under the exhaust valve (12) is displaced and goes out the engine
exhaust port (11).
5. Illustrated in Figure 14, the Hybrid Engine assigns the middle air transfer
stage and the final exhaust stage to both pump cylinder (8) and engine
cylinder (18). The pump intake valve (2) is closed, the engine
compression valve (10) is open and the engine exhaust valve (12) is
open. The pump piston (6) moves up, pushing the intake air from the
pump cylinder (8) into the engine cylinder (18), displacing the hot
exhaust gas directly below the compression valve (10). The engine
piston (16) moves up, pushing the hot exhaust gas directly below the
exhaust valve (12) out the exhaust port (13).
6. Illustrated in Figure 15, the Hybrid Engine assigns the final air transfer
stage and the early compression stage to both the pump cylinder and
the engine cylinder. The pump intake valve (2) is closed, the engine
compression valve (10) is open and the engine exhaust valve is closed.
The pump piston is moving up and the engine piston is moving up.
Injector (21) delivers the fuel. The two cylinders are coupled and both
pistons are compressing the air/fuel mixture.
Five cycles are completed and process goes back to step a.
14
CA 02879253 2016-04-21
Cylinder Head Connection
Shown in Figures 2, 3 and 4, the Hybrid Engine shows the top dead center (4)
of the pump piston (6) in line with the top lip of the air passageway (9) of
the
engine cylinder head (11) sub-assembly. This makes a shortest air
passageway for faster transferral of as much air as possible.
Crank Angle
As acknowledged in the Background, the pump crank throw (26) leading the
engine crank throw (27) at right angle or 90 degrees was introduced in 1807.
In the Hybrid Engine, the value of the crank throw angle (30) between the
crank throws (26 & 27) is that it provides a wider range between 10 and 110
degrees.
Shown in Figures 5, 6 and 7, in the Hybrid Engine the crank throw (26) which
is connected to the pump piston (6) leads the crank throw (27) connected to
the engine piston (16). Whether the crankshaft (28) is in a clockwise or
counterclockwise rotation, the pump piston (6) reaches its top dead center
(4) and bottom dead (7) center ahead of the engine piston (16) reaching its
top dead center (14) and bottom dead center (17) respectively.
Given that the position of engine crank throw (27) of the engine piston (16)
stays the same, Tables 1, 2 and 3 shows that using different values for the
crank throw angle (30), the position the pump crank throw (26) points to
changes. For example, the combustion cycle of the engine cylinder (19)
begins when the engine crank throw (27) of the engine piston (16) is at 0 or
360 degree and ends when the engine crank throw (27) reaches arc 6 to 7.
The engine piston (16) is moving down.
1. With a value of 67.5 degrees for crank angle (30) in Table 1, the pump
piston (6) is moving down when the leading pump crank throw (26) is at
arcs 3 to 8 and ending at arcs 9 to 10 when the pump piston (6) is
moving up.
2. With a value of 45 degrees for crank angle (30) in Table 2, the pump
piston (6) is moving down when the leading pump crank throw (26) is at
CA 02879253 2016-04-21
arcs 2 to 8 and ending at arcs 8 to 9 when the pump piston (6) is moving
up.
3. With a value of 90 degrees for crank angle (30) in Table 3, the pump
piston (6) is moving down when the leading pump crank throw (26) is at
arcs 4 to 8 and ending at arcs 11 to 12 when the pump piston (6) is
moving up.
Table 4 summarizes the impact of different values, from 45 degrees, 67.5
degrees and 90 degrees, for the crank throw angle (30) on the position of the
pump crank throw (26) and the position of the engine crank throw (27)
during the early compression and final compression stages. By implication,
this also has a direct impact on the final position of the engine piston (16)
at
the start of the early compression and at the end of the final compression
stages. Anyone in the field can deduce that the eventual size of the
compression chamber (30), the pre-ignition pressure inside the combustion
chamber and the resulting engine's compression ratio will depend on when
the exhaust valve closes at the start of the early compression stage.
Compression Integrity
Referring to Figure 8, the Hybrid Engine shows the stem of the compression
valve (10) fitted with a compression seal (22) to preserve compression
integrity and to prevent the air/fuel mixture from leaking out through the
clearance space between the stem hole and the compression valve (10) stem
in the engine cylinder (11) head.
Referring to Figure 2, 3 & 4, the Hybrid Engine is designed to maximize the
air transfer from pump cylinder (8) into the engine cylinder (18).
1. The pump piston's top dead center (4) is made higher than the engine
cylinders' top dead center (14),
2. The pump piston at its TDC and the pump engine piston (15) ring below
the lower lip of the air passageway (9) of the engine cylinder head (11)
sub-assembly ensures that the air/fuel mixture does not leak into the
pump crankcase.
16
CA 02879253 2016-04-21
Compression Plate
Referring to Figure 2, 3 & 4, the Hybrid Engine shows the engine has an
optional compression plate (1) sandwiched between the engine cylinder
head (11) and the cylinder block (29). Shown in Figures 9 the compression
plate (1) has a spark plug hole (5), an optional fuel injection hole (9), a
compression valve hole (2) and an exhaust valve hole (6). The valve holes (2
& 5) have inner and outer circumferences (4 &3, 7 & 8) designed to promote
swirl of the incoming intake air/fuel mixture and faster outflow of the
exhaust gas respectively. In addition the compression plate:
1. serves as the top boundary for the combustion chamber,
2. allows:
a. the compression plate to absorb most of the stresses from high
temperature and combustion pressure,
b. design options for shape and contour of the compression valve hole
(3a) to optimize and promote the swirl of the air inflow into the
engine cylinder (18),
c. design options for shape and contour of the exhaust valve hole (4a)
to maximize the outflow of exhaust gas from the engine cylinder (18),
d. some flexibility in manufacturing the pump cylinder head (1) and
engine cylinder head (11) as either two separate units or as one
single unit.
3. reduces:
a. the stresses from high temperature and combustion pressure on the
entire cylinder head assembly,
b. weight by using a lighter material for the pump cylinder head (1) and
engine cylinder head (11).
4. Lowers the cost of maintenance related to cracked or warped cylinder
heads; replacing only the compression plate is cheaper than replacing
the complete cylinder head assembly.
Cylinder Volume
17
CA 02879253 2016-04-21
Referring to Figures 2, 3 & 4, the Hybrid Engine the pump cylinder (8) and the
stroke of the pump piston (6) is longer than that of the engine cylinder (18)
and the engine piston (16). The pump cylinder volume capacity is greater
than the engine cylinder's volume capacity which compensates for the
scavenging loss of intake air mass. Although this can also be accomplished
through other means, such as larger pump cylinder bores and larger pump
piston (not shown), this option is easily implemented in conjunction with the
configuration of the air passageway (9).
18
CA 02879253 2016-04-21
Summary of the Invention
The Hybrid Engine is an unprecedented cross between a single cylinder 2 stroke
pump and a single cylinder 2 stroke 4 cycle internal combustion engine. The
Hybrid Engine uses 2 strokes of the pump plus the simultaneous 2 strokes of
the
engine to circulate fresh air through the two cylinders and back to the
atmosphere. Using the intake air from the pump, the engine completes the
Hybrid Engine's 5 cycles of internal combustion to turn the crankshaft. Since
the
2 strokes are happening simultaneously inside 2 cylinders, the Hybrid Engine
takes only 2 strokes to turn its crankshaft one complete revolution. The
Hybrid
Engine is a 2-stroke 5-cycle internal combustion engine. The invention can be
classified under either 2-stroke or 4-stroke internal combustion engine.
The Hybrid Engine uses five cycles to produce internal combustion:
1. Additional cycle added to the conventional 4 cycles of internal
combustion.
2. Subdivision of the resulting five cycles into stages.
3. The cylinder head design, i.e. the passageway, the compression seal and
the compression plate, that allows the stages to be performed in either
the pump cylinder and/or the engine cylinder.
The stages of the 5 cycles of internal combustion in the Hybrid Engine are:
1. An air transfer cycle to move intake air from the pump cylinder to the
engine cylinder inserted between the conventional intake cycle and the
compression cycle and subdivided into an early air transfer stage, a
middle air transfer stage and a final air transfer stage.
2. The conventional intake cycle is renamed air intake cycle when the
pump cylinder admits air from the atmosphere; fuel is injected either
during the air transfer cycle, the compression cycle or both; these stages
are early air intake and final air intake.
3. Compression of the air/fuel mixture includes an early compression and a
final compression stages.
4. Combustion of the air/fuel mixture takes place only a single stage.
19
CA 02879253 2016-04-21
5. The procedure to push smoke and other combustion by-products out of
the combustion chamber into the atmosphere is done during an early
exhaust stage, a middle exhaust stage and a final exhaust stage.
The Hybrid Engine has the following notable features:
1. Sixteen equal arc subdivisions of the 360 degree circumference, using
the arc positions to define the opening and closing of the intake,
compression and exhaust valves.
2. The crank throw assignments of the pump piston and engine piston with
the pump piston in the lead, arriving at its dead centers ahead of the
engine piston; the value of the angle between crank throws, also known
as crank throw angle, directly impacts the resulting compression ratio
and the behavior of the single cylinder 2 stroke engine. A cost/benefit
research and development study on using a gear-shifting mechanism to
dynamically change the crank throw angle can be designed.
3. The compression seal around the stem of the compression valve.
4. The optional compression plate sandwiched between the engine
cylinder head sub-assembly and the engine cylinder block.
5. During the air transfer and compression cycles, fresh intake air mixes
with the exhaust gas inside the engine cylinder. This makes the use of
exhaust gas recirculation valve redundant.
6. The larger pump cylinder volume capacity also makes the use of
turbocharger unnecessary.
7. A 4 cylinder 2 stroke Hybrid Engine will use 50% less spark plug, 50% less
fuel injector, no turbocharger and no exhaust gas recirculation valve
compared to a comparable current 4 cylinder 4 stroke engine.
The Hybrid Engine can easily be manufactured for the original equipment
manufacturers market using current technologies. This applies also to the
parts
of the engine, such as cylinder head sub-assembly, the crankshaft, the
compression plate and the modified version of engine control unit software
module, for conversion and after sales market.
CA 02879253 2016-04-21
The invention is a hybrid, four-cylinder, 2-stroke, 5-cycle engine that turns
the
crankshaft two times faster than a comparable conventional four-cylinder, 4
stroke, 4-cycle engine does.
21
Pump Piston (6)
Engine Piston (16)
Exhaust
Engine Shared Intake
Compressio
Cycle Stage
Valve
Drawing ? Valve (2) Piston Crank Throw
Piston Crank Throw n Valve (10)
(12)
Direction _ Position Direction Position
Air Intake, Early
Figure 10 0 to 3 Up 13 to 0
.
Compression Final Open Down
Close
Air Intake Final 3 to 8
Close
Figure 11 No 0 to
6
Combustion 8 to 9
Exhaust Down
Figure 12 Early 9 to 10 6 to
7
Air Transfer
Exhaust
7 to 8
Figure 13
Open
Air Transfer Middle Close Up 10 to 12 8 to
9
Air Transfer 9 to 10 Open
Figure 14 Yes
0
Exhaust Final 12 to 14
UP 10 to 11
o
Air Transfer
Final i..)
Figure 15 14 to 0 11 to 13
Close co
Compression Early
ko
i..)
Table 1¨ Stages, Piston Directions and Valve Controls Using 67.5 Degrees Crank
Throw Angle (xi
u.)
i..)
o
Pump Piston (6)
Engine Piston (16) 1-,
Exhaust
cn
Engine Shared Intake
Compression O
Cycle Stage
Valve .o.
Drawing ? Valve (2) Piston Crank Throw
Piston Crank Throw Valve (10) 1
(12)
i..)
Direction Position
Direction Position
Early &
Air Intake
Figure 10 Final 0 to 2 Up 14-0
Open Down
Close
Compression Final No
Close
Figure 11 Combustion 2 to 8 0 to
6
Exhaust
Figure 12 Early 8 to 9 Down 6 to
7
Air Transfer
Exhaust
7 to 8
Figure 13
Open
Air transfer Middle 9 to 12 8 to 9
close Up
Air Transfer 9 to 10 Open
Figure 14 _____________ Yes
Exhaust Final 12 to 13
Up 10 to 11
Air Transfer Final
Figure 15 13 to 0 11 to 14
Close
Compression Early
Table 2 ¨ Stages, Piston Directions and Valve Controls Using 45 Degrees Crank
Throw Angle
3.
Pump Piston (6) Engine
Piston (16) Exhaust
Engine Shared Intake
Compression
Cycle Stage
Valve
Drawing ? Valve (2) Piston Crank
Throw Piston Crank Throw Valve (10)
(12)
Direction Position
Direction Position _
Air Intake Early
Figure 10 0 to 4 Up
12-0
Compression Final Open Down
Close
Air Intake Final 4 to 8
Close
Figure 11 No
0 to 6
Combustion 8 to 10
Exhaust
Figure 12 Early
Air Transfer Down
to 11 6
to 7
Exhaust
Figure 13
Open o
Air Transfer Middle Close Up
o
Air Transfer 11 to 12
7 to 8 Open n.)
co
Figure 14 Yes
Exhaust Final 12 to 15
8 toll ko
_
n.)
cri
Air Transfer, Final Up
w
Figure 15 15 to 0
11 to 12 Close
Compression Early
n.)
I
o
1-,
Table 3 ¨ Stages, Piston Directions and Valve Controls Using 90 Degrees Crank
Throw Angle 0,
O
Ø
i
iv
1-,
Pump Piston (7) Engine
Piston (17) Exhaust
Angle in Compression Shared
Intake Compression
Drawing
Valve
Degrees Stage ? Valve (2) Piston Crank
Throw Piston Crank Throw Valve (10)
Direction Position
Direction Position (12)
Early Yes Up 13 to 0 Up ,
11 to 14 Open Close
Figure 3 45 Close
Final No
14 to 0 Close , Close
Early Yes Up 14 to 0 Up
11 to 13 Open . Close
Figure 2 67.5 Close
Final No
13 to 0 Close Close
Early Yes Up 15 to 0 Up
11 to 12 Open Close
Figure 4 90 Close
Final No
12 to 0 Close Close
Table 4¨ Effect of Different Crank Throw Angles on Compression Stages Timing
1
