VARIABLE COMPRESSION ENGINE
FIELD OF THE INVENTION
[0001] The present invention relates to internal combustion engme, more
particularly, to internal combustion engine having variable compression.
BACKGROUND
[0002] In an internal combustion engme, many a times, compressiOn ratio IS
increased for better performance and bettet fuel economy. Engine with a highcompression
ratio poses a threat of higher probability of occurrence of engine knocking,
in particular, at. relatively high engine loads, low engine revolution per minute (RPM) at
full throttle condition, etc. In a contrary, if the engine compression ratio is lowered,
output torque of the engine and thus the engine output performance is compromised at
part-throttle condition.
[0003] It is known to vary (e.g, increase or decrease) the volume of the combustion
chamber of the engine to change the compression ratio of engine. One such mechanism
is disclosed in a European patent application number EP1503060Al. The patent
application EP 1503 060A 1 discloses an internal combustion engine variable compression
ratio system that enables an outer piston to be moved to and held at a low compression·
ratio position and a high compression ratio position simply and reliably without rotating
the outer piston thereby making the compression ratio variable. An operating device
disposed between an inner piston and the outer piston moves and holds the outer piston ·
relative to the inner piston alternately at the low compression ratio position close to the
piston pin and at the high. compression ratio position close to the combustion chamber.
However, such internal combustion engine involves complex mechanism and its
implementation involves excessive modifications in conventional internal combustion
engine, which increases the overall cost of the engine.
SUMMARY
(0004] A four stroke internal combustion engine of a vehicle is disclosed. In an
embodiment, the four stroke internal combustion engine comprises a cylinder block, a
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IP··0. n!;JE;·:ILl.\.U.h.lTii., GZ-89-2015
17
bleeding port and a primary controlling means. The cylinder block comprises a cylinder
' bore. The bleeding port is provided on a wall of the cylinder bore. The bleeding port
fluidly connects the cylinder bore to a passageway. The primary controlling means is
provided to the bleeding port to control opening and closing of the passageway during a
compression stroke of the four stroke internal combustion engine based on one or more
engine running parameters associated with the vehicle for controlling a fluidic
communication between the cylinder bore and the passageway. The controlling of the
fluidic communication enables varying an amount of charge present in the cylinder bore
during the compression stroke.
[0005] In an embodiment, the primary controlling means comprises one or more
valves, and the four stroke internal combustion engine further comprises a control unit
and a valve operating means. The control unit is configured to access the one or more
engine running parameters and generate a signal corresponding to the one or more
accessed engine running parameters. The valve operating means controls opening and
closing of the one or more valves based on the signal received from the control unit. In
an embodiment, the one or more valves comprise at least one of a rotary valve, a puppet
valve and a solenoid valve. In an embodiment, the valve operating means is an electric
motor operated by the control unit.
[0006] In an embodiment, the one or more engine running parameters comprises at
least one. of an engine temperature, an engine revolution per minute (RPM), an engine
load and an information of knocking of the four stroke internal combustion engine. In an
embodiment, the primary controlling means is. a combination of two .. or more valves
connected in series in the passageway. In an embodiment, the control unit is configured
to, based on intensity of the one or more engine running parameters, actuate the valve
operating means to open the primary controlling means for an estimated time period and
with a specified degree of opening in the compression stroke.
[0007] In an embodiment, the four stroke .internal combustion engine further
comprises a rotary valve for controlling opening and closing of the bleeding port during
the compression stroke of the four stroke internal combustion engine. In an embodiment,
the rotary valve is fixedly mounted to an auxiliary shaft being rotated by a crankshaft via
an auxiliary timing transmission device, where the crankshaft is housed in a. crankcase.
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IPO DELHI 82.-09-281,5. 1:1. 12'
The four stroke internal combus~ion engine further comprises a piston reciprocatingly
movable in the cylinder bore and is connected to the crankshaft by a connecting rod. In
an embodiment, the bleeding port is provided at an intermediate position between a top
dead centre (TDC) and a bottom dead centre (BDC) of the piston in the cylinder bore.
[0008] In an embodiment, the rotary valve is fixedly mounted to an auxiliary shaft
being rotated by a camshaft via an auxiliary timing transmission device, where the
camshaft is rotatably supported on a cylinder head of the four stroke internal combustion
engine. The camshaft is operatively configured to open and close each of an intake valve
and an exhaust valve of the four stroke internal combustion engine.
[0009] In an embodiment, the rotary valve is a disc comprising an elongated slot
therethrough. The elongated slot is an· arc shaped opening positioned at a radial distance
from an axis of the auxiliary shaft. Moreover, when the elongated slot overlaps with the
bleeding port, the fluidic communication is maintained between the cylinder block and
upto the primary controlling means in the passageway.
[0010] In an embodiment, the passageway is connected to an intake system of the
four stroke internal combustion engine. Charge escaped from the cylinder bore through
the passageway is re-circulated into the intake system. In an embodiment, the four stroke
internal combustion engine further comprises an auxiliary chamber configured between
the passageway and the intake system.
[0011] In an embodiment, the four stroke internal combustion engme further
comprises a secondary controlling means disposed between the auxiliary· chamber and
the intake system. The secondary controlling means is controlled by a control unit, where
the control unit is configured to open the secondary controlling means during an intake
stroke of the four stroke internal combustion engine. In an embodiment, the auxiliary
chamber is filled with a fuel adsorbing material.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0012] The invention itself, together with further features and ~ttended advantages,
will become apparent from consideration of the following detailed description, taken in
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IPO DELHI 02-99-2915 17. 12
conjunction with the accompanying drawings. One or more embodiments of the present
invention are now described, by way of example only wherein like reference numerals
represent like elements and in which:
[0013] Figure 1 is side view of a two wheeled vehicle which incorporates a four
stroke internal combustion engine with variable compression, according to an .
embodiment of the present invention;
[0014] Figure 2. is a cross sectional view of the four stroke internal combustion
engine with variable compression, according to an embodiment of the present invention;
[0015] Figure 3 is another cross sectional view of the four stroke internal combustion
engine with variable compression, according to an embodiment of the present invention;
[0016] Figure 4 is a . cross sectional view of the four stroke internal combustion
engine with variable compression, according to an embodiment of the present invention;
and
[0017] Figure 5 is another cross sectional view of the four stroke internal combustion
engine with variable compression, according to an embodiment of the present invention.
[0018] The drawings referred to in this description are not to be understood as being
drawn to scale except if specifically noted, and such drawings are only exemplary in
nature.
DETAILED DESCRIPTION
[0019] While the invention is susceptible to various modifications and alternative
forms, an embodiment thereof has been shown by way of example in the drawings and
will be described here below. It should be understood, however that it is not intended to
limit the invention to the particular forms disclosed, but on the contrary, the invention is
to cover all modifications, equivalents, and alternative falling within the spirit and the
scopt! ofthe invention.
[0020] The terms "comprises", "comprising", or any other variations thereof, are
intended to cover a non-exclusive inclusion, such that a setup, device .or method that
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IPO DELHI 02-09-2915 17 12
.....---------------------------------------
comprises a list of components or steps does not include only those components or steps
but may include other components or steps not expressly listed or inherent to such setup
or device or method: In other words., one or more elements in a system or apparatus
proceeded by "comprises ... a" does not, without more constraints, preclude the existence
of other elements or additional elements in the system or apparatus.
[0021] An embodiment of the invention is explained with reference to a two wheeled
vehicle such as motorcycle and a four stroke internal combustion engine, however,
person skilled in the art would appreciate that the same may be extended to other
vehicles and engines as well.
[0022] For the better understanding of this invention, reference would now be made
to the embodiment illustrated in the accompanying figures and description here below,
further, in the following figures; the same reference numerals are used to identify the
same components in various views.
[0023] Figure 1 is a side view of a two wheeled vehicle which incorporates a four
stroke internal combustion ·engine (hereinafter referred to as 'internal combustion
engine' or 'engine') with variable compression, according to an embodiment of the
present invention. The two wheeled vehicle (0 1) comprises, inter-alia, a body frame, a
front fork (112), a front fender (106), a front wheel (108), a headlight (110), a steering
handlebar (132), a fuel tank (102), an engine (E), an air cleaner assembly (114), a fuel
supply system (116), a rear suspension (118), a swing arm (122), a dress guard (124), a
rear wheel (126), a rear fender (128), a taillight assembly (130), and a seat (104). It may
be noted that the vehicle is shown to include above stated parts, however, those skilled in
the art would appreciate that the vehicle includes other parts which may not be relevant
for explaining the present invention and hence are not shown and described.
[0024] Figure 1 further illustrates a body frame of the two wheeled vehicle (01). The
·body frame of the two wheeled vehicle (01) comprises a main frame (202), a head pipe
(207), a pair of seat rail members such as .a left seat rail member (204a) and a right seat
rail member (not shown in Figures), a pair of sub-frame members such as a left subframe
member (206a) and a right sub-frame member (not shown in Figures), a down
frame member (208) and one. or more brackets. The main frame (202) having a front
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IPO DELHI 02-99-2015 17 1 2
portion (202a) which extends obliquely in the rearward and downward direction from the
head pipe (207) and a rear portion (202b) changing the direction and thereafter,
extending further downward, the pair of seat rails i.e. the left seat rail member (204a) and
the right seat rail member extend from rear end of the front portion (202a) of the main
frame (202), the down frame member (208) obliquely extends in the downward direction
from the lower portion of the head pipe (207), the left sub-frame member (206a) and the
right sub-frame member are connected to the rear portion (202b) of the main frame (202)
and to the rt:spective left seat rail member (204a) and right seat rail member through
bracket(s).
[0025] As illustrated in Figure 1, the front fork (112) is rotatably attached to the head
pipe (207) enabling free steering. The front fork (112) supports the front wheel (1 08) at.
lower end thereof and the steering handlebar (132) at upper end thereof. The fuel tank
(1 02) is supported by the front portion (202a) of the main frame (202) of the two
wheeled vehicle (01) at a position upper than the engine (E).
[0026] The left seat rail member (204a) and the right seat rail member primarily
intended to support the seat (1 04) for a rider and/or pillion, are disposed above the rear
'
wheel (126). The dress guard (124) is connected to the left seat rail member (204a); the
dress guard (124) is intended to cover the left side of the rear wheel (126). The rear
wheel (126) is covered from above by the rear fender (128). The rear wheel suspension
section includes. the swing arm (122) supporting the rear wheel (126) and at least one
rear suspension (118) attached between the swing C!flll (122) and the left seat rail member
(204a) or the right seat rail member. The tail lamp assembly (130) is mounted on the rear
·fender (128).
. [0027] As illustrated in Figure 1, the engine (E)· is mounted on the two wheeled
vehicle (0 1 ). The engine (E) is disposed in a space surrounded by the front portion
. (202a) and the rear ·portion (202b) of the main frame (202), and the down frame (208),
and is supported by the rear portion (202b) of the main frame (202) and the lower end of
the down frame (208) using one or more brackets (not shown) on the down frame (208)
and the rear portion (202b) of the main frame (202). A transmission (not shown) is
arranged behind the engine (E) to transmit the power output from the engine (E) to the
rear wheel (126) via a transmission means.
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IPO DELHI 82-09-2915 17 : 12
[0028] As shown in Figures 2 to 5, the engme (E) has an engme body (02)
comprising a crankcase (04), a cylinder block (06) coupled to an upper portion of the
frontal end of the crankcase (04) and projecting upwardly and forwardly therefrom, and a
cylinder head (09) coupled to the upper end of the cylinder block (06). In an
embodiment, the engine body (02) can take a form comprising the crankcase (04), the
cylinder block (06) coupled to a frontal portion of the front end of the crankcase (04) and
projecting forwardly therefrom (and slightly upwardly), and the cylinder head (09) is
coupled to the frontal end of the cylinder block (06). The cylinder head (09) is covered
with a cylinder cover (08).
[0029) A crankshaft (10) housed in the crankcase (04) is rotatably supported on the
left and right side walls of the crankcase (04) using bearings. A piston (12) is
reciprocatingly movable in a cylinder bore (14) in the cylinder block (06). The piston
(12) is connected to the crankshaft (10) by a connecting rod (16). Further, a bleeding port
(18) in fluidic communication with the cylinder bore (14) is provided on the sidewall of
the cylinder block (06). The bleeding port (18) is provided at an intermediate position
between the top dead centre (TDC) and the bottom dead center (BDC) of the piston (12)
in the cylinder bore (14). There is provided a passageway (24) establishing fluidic
communication between the intake system (20) and the cylinder bore (14).
[0030] . The cylinder head (09) has a combustion chamber (38) being faced by the top
surface of the piston. (12), an intake port (40) communicating. with the combustion
chamber (3 8) and opening at a first surface of the cylinder head (09), and an exhaust port
(42) communicating with the combustion .. chamber (38) and opening at a second surface
of the cylinder head (09). An intake valve (44) for opening and closing the intake port
( 40) is mounted in the cylinder head (09). An exhaust valve ( 46) for opening and closing
the exhaust port (42) is mounted in the cylinder head (09). The intake valve (44) and the
exhaust valve ( 46) are operated by a valve operating mechanism ( 48) which is disposed
in a valve operating chamber (50) in the cylinder head (09). The intake port (40) is in
fluidic communication with the intake system (20). The intake system (20) comprises an
intake pipe at one end connected to the intake port ( 40) and at other end connected to a
throttle body, the throttle body is coupled with the air intake system such as air cleaner
and the fuel intake system such as fuel tank. In an embodiment, the air intake system
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IPO DELHI 02-09-2915 17"12
-----------------------------------
may include the fuel injection system such as fuel pump instead of the throttle body. The
present invention is not limited to any particular type of fuel intake system. An exhaust
pipe is connected to the exhaust port ( 42) and a muffler is connected to the other end of
the exhaust pipe.
[0031] The valve operating mechanism (48) comprises a camshaft (30) rotatably
supported on the cylinder head (09) by a pair of left and right bearings, where the
camshaft (30) runs parallel to the crankshaft (10) in a position intermediate between the
intake valve (44) and the exhaust valve (46). An intake rocker arm (62) is pivotally
supported on the cylinder head (09) and is operatively interconnecting the camshaft (30)
and the intake valve (44), and a valve spring (64) is provided for normally biasing the
intake valve (44) in a valve closing direction. An exhaust rocker arm (66) is pivotally
supported on the cylinder head (09) and is operatively interconnecting the camshaft (30)
and the exhaust valve (46), a valve spring (64) is provided for normally biasing the
exhaust valve ( 46) in a valve closing direction.
[0032] The camshaft (30) is operatively coupled to the crankshaft (1 0) by a timing
transmission device. The timing transmission device comprises a drive sprocket (70)
fixed to the crankshaft ( 1 0) disposed outwardly of and adjacent to a left bearing (72)
which supports the crankshaft (10), a driven sprocket (74) fixed to an end of the
camshaft (30). An endless timing chain (76) trained around the sprockets (70) and (74).
The timing transmission device is capable of transmitting rotation of the crankshaft (1 0)
to the camshaft (30) at a speed reduction ratio of 1/2. The timing chain (76) is disposed
in a timing chain passage which is defined in a side wall of the cylinder block (06).
[0033] The crankcase (04) accommodates a transmission having an input shaft (82)
and an output shaft (84) which extends parallel to the crankshaft (10). The input and
output shafts (82), (84) are supported on the opposite side walls ofthe crankcase (04) by
respective pairs of bearings. A transmission gear train is. interposed between the input
shaft (82) and the output shaft (84). Power generated by the crankshaft (10) is
transmitted through a primary speed reduction to the input shaft (82), and then
transmitted from the input shaft (82) through a selected transmission gear train to the
output shaft (84) from which the power is transmitted through a chain transmitting
device or the like to the rear wheel (126), thus rotating the rear wheel (126). In an
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IPO DELHI 02~09-2015 17 12
-----------------------
embodiment, power generated ~y the crankshaft (1 0) is transmitted through a continuous
variable transmission. Further, it should be appreciated that the present invention should
not be limited to any particular type of transmission.
[0034] A typical four stroke internal combustion process comprises strokes such as
an intake stroke, a compression stroke, an expansion stroke and an exhaust stroke in one
cycle. During the intake stroke, the piston (12) moves downwards i.e. from the top dead
center (TDC) to the bottom dead center (BDC), and during this stroke, the camshaft (30)
pushes up the intake rocker arm (62) to open the intake valve (44) and the charge is
inducted into the cylinder bore (14). The communication between the cylinder bore (14)
and the passageway (24) remains closed during this stroke.
[0035] During the compression stroke (as illustrated in Figure 2 and Figure 3), the
intake rocker arm (62) closes the intake valve (44) and the exhaust rocker arm (66)
maintains the closed position of the exhaust valve (46) and the piston (12) moves in
upward direction from the bottom dead center (BDC) to top dead center (TDC). If the
communication between the cylinder bore (14) and the intake system (20) through the
passageway (24) is in closed state then the charge in the cylinder bore (14) gets
compressed as the piston (12) moves in upward direction i.e. from the bottom dead
center (BDC) to the top dead center (TDC). If the communication between the cylinder
bore (14) and the intake system (20) through the passageway (24) is established then the
charge escapes out through the bleeding port (18) till the fluidic communication between
the cylinder bore (14) and the iritake system (20) is blocked. Sometimes, if the
communication between the cylinder bore (14) and the intake system (20) through the
passageway (24) is established then part of the charge escapes out through the bleeding
port (18) and remaining part of the charge gets compressed with upward movement of
the piston (12). Once the communication between the cylinder bore (14) and the intake
system (20) through the passageway (24) is blocked, then further upward movement of
the piston (12) causes compression of the charge. The fluidic communication between
the cylinder bore (14) and the intake system (20) is blocked in the compression stroke
itself, preferably, the fluidic communication between the cylinder bore (14) and the
intake system (20) is blocked at such position of piston that the escaped charge in the
passageway (24) do not enter into the crankcase (04).
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IPO D· E· LH· I· e-.2-.0S-2015 11:12
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[0036] In the expansion stroke, the intake valve ( 44) and the exhaust valve ( 46) are
in the closed position and the compressed charge is ignited by a spark plug (90) forcing
the piston (12) downwardly. The communication between the cylinder bore (14) and the
intake system (20) through the passageway (24) remains closed during the expansion
stroke.
[0037] In the exhaust stroke, the exhaust rocker arm (66) lifts up the exhaust valve
(46) and the exhaust gases are emitted from the cylinder bore (14). The intake valve (44)
and the communication between the cylinder bore (14) and the intake system (20)
through the passageway (24) remains closed during the exhaust stroke.
[0038] In some engines there may be overlap of opening and closing of the intake
valve (44) and the exhaust valve (46).
[0039] It will be known to those skilled in the art that a geometric compression ratio
of an engine is defined as the ratio of the volume enclosed by the cylinder of an internal
combustion engine at the beginning of the compression stroke to the volume enclosed at
the end of the compression stroke. However, a dynamic compression ratio depends on
the pressure ratio. In terms of pressure, the dynamic compression ratio is as per the
following expression:
P = Pox (DCR)0
Where 'Po' is the cylinder pressure at the BDC, 'P' is the cylinder pressure at the TDC
and 'DCR' is dynamic compression ratio.
[0040] Thus, it is evident from the expression that the dynamic compression ratio
(DCR) is dependent on peak compression pressure i.e. the dynamic compression ratio of
an engine will be more if the peak compression pressure· is more and dynamic
compression ratio will be less if the peak compression pressure is less.
[0041] As per an embodiment of the present invention, the passageway (24) is
provided with a primary controlling systein comprising a primary controlling means (92)
disposed therein, adapted to control the opening and the closing of the passageway (24)
during the compression stroke of the engine (E). For instance, the fluidic communication
11
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between the cylinder bore (14) and the intake system (20) is established through the
passageway (24) when the primary controlling means (92) is in an opened state, and the
fluidic communication between the cylinder bore (14) and the intake system (20) is
blocked through the passageway (24) when the primary controlling means (92) is in a
closed state. In an embodiment, the primary controlling means (92) is controlled by a
control unit (C). In an embodiment, the primary· controlling means (92) is a valve
actuated by a valve operating means (98), where the valve operating means (98) is
controlled by the control unit (C). In an embodiment, the control unit (C) is an electronic
control unit, and hereinafter also referred to as the electronic control unit (C). In an
embodiment, the primary controlling means (92) is a combination of two or more valves
connected in series in the passageway (24). In an embodiment, the valve is a rotary valve
or a puppet valve or a solenoid valve. In an embodiment, the electronic control unit (C)
operates the valve operating means (98), for example by using an electric motor to open
and close the primary controlling means (92) i.e, valve. In an embodiment, the electronic
control unit (C) controls the duration of opening of the primary controlling means (92)
such as valve. In an embodiment, the electronic control unit (C) controls the degree of
opening of the primary controlling means (92).
[0042] The electronic control unit (C) is configured to access (e.g., by sensing or
receiving in form of inputs) the information relating to one or more engine running
parameters. Examples of the one or more engine running parameters include, but are not
limited to engine temperature,. engine revolutions per minute (RPM),· engine load,
information of knocking of engine, etc. In an embodiment, one or more sensors can be
used to detect such engine running parameters. In an embodiment, the electronic control
unit (C) is equipped with intelligence to determine, based on the engine running
parameter, whether the compression of the engine (E) should be decreased or not.
Further, the electronic control unit (C) may also be configured to determine the
compression stroke based on the inputs. When the Electronic control unit (C) determines
that compression of the engine (E) is to be decreased, it generates a signal for actuating
the valve operating means (98) (e.g., an electric motor) to open the primary controlling
means (92) (e.g., the valve) in the compression stroke. The electronic control unit (C)
provides the signal to the valve operating means (98) for actuating the valve operating
means (98) (e.g., electric motor) to close the primary controlling means (92) after a
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IPD DELHI 92-09-2015 17 1.2
specific time period, in the compressiOn stroke itself. Herein, the time period may
depend upon the intensity of the engine running parameter(s). In an embodiment, the
electronic control unit (C:) actuates the valve operating means (98) to open the primary
controlling means (92) (e.g., the valve), partially, for an estimated time period with a
specified degree of opening, in the compression stroke itself. The time period and degree
of opening depends upon the intensity of the engine running parameter(s). Generally, the
electronic control unit (C) actuates the valve operating means (98) (e.g., electric motor)
· to close the primary controlling means (92) (e.g., valve) during the compression stroke
and before the piston (12) overlaps the bleeding port (18).
[0043] In an example, when the engine (E) is running at lower load condition, the
electronic control unit (C) does not open the primary controlling means (92) at all
enabling the engine (E) to run at higher dynamic compression ratio. Further, when the
electronic control unit (C) determines that load on the engine (E) is beyond a
predetermined load limit, electronic control unit (C) facilitates opening and closing of the
primary controlling means (92) in a manner as described above, thereby enabling the
engine (E) to run at a lower dynamic compression ratio. Accordingly, the engine (E) is
adapted to work with variable compression controlled by the electronic control unit (C).
The electronic control unit (C) provides an effective compression ratio by opening and
closing of the primary controlling means (92) (e.g., valve) based on the engine running
parameters. With this controlled compression ratio by the electronic control unit (C), the
engine (E) is operated optimally in different load conditions.
[0044] ·In an embodiment, the primary controlling system is a combination of two or
more primary controlling means (92, 94a) such as valve similar to . the primary
controlling means (92) described above being controlled by the electronic control unit
(C) and a rotary valve (94a} being controlled by a timing transmission mechanism. In an
embodiment, the rotary valve (94a) is in the form of rotating disc. The rotary valve (94a)
is fixedly mounted to an auxiliary shaft (28) being rotated by the crankshaft (10) or the
camshaft (30). The rotary valve (94a) is adapted to open and close the bleeding port (18)
during the compression stroke. The rotary valve (94a) is fixedly mounted to the auxiliary
shaft (28) which is rotatably supported at one end by the cylinder block (06). In an
embodiment, the auxiliary shaft (28) is operatively coupled to the camshaft (30) by an
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IPO DELHI 92-09-2015 17 12
auxiliary timing transmission device (32). The auxiliary timing transmission device (32)
is capable of transmitting rotation of the camshaft (30) to the auxiliary shaft (28) at the
same speed. In another embodiment, as illustrated in Figure 2, the auxiliary shaft (28) is
operatively coupled to the crankshaft (1 0) by the auxiliary timing transmission device
(32), where the auxiliary timing transmission device (32) is capable of transmitting
rotation of the crankshaft (10) to the auxiliary shaft (28) at the speed reduction ratio of
Yz. In an embodiment, the auxiliary timing transmission device (32) is similar to that of
the timing transmission device for the inlet valve (44) and the exhaust valve (46).
[0045) In an embodiment, as illustrated in the Figure 2, the rotary valve (94a)
(hereinafter referred as a disc (94a)) in the form of the disc has an elongated slot (96)
there though. The elongated slot (96) is an arc shaped opening located at particular radial
distance from the axis of the auxiliary shaft (28). The disc (94a) is timed in such way that
the elongated slot (96) overlaps with the bleeding port (18) only during the part of
compression stroke. In an embodiment, the disc (94a) forms a seal proof arrangement
with the bleeding port (18) such that communication between the cylinder bore ( 14) and
the passageway (24) is established only when the elongated slot (96) overlaps with the
bleeding port (18). The elongated slot (96) on the disc (94a) on the auxiliary shaft (28) is
located such that it opens the bleeding port (18) at the start or during the compression
stroke only and the angular length of the elongated slot (96) is such that it closes the
bleeding port (18) during the compression stroke itself and before the piston (12)
overlaps the bleeding port (18).
[0046) , During running of the engine (E), as the ·disc (94a) completes one rotation in
one cycle, the disk (94a) opens the bleeding port (18) in each cycle irrespective of the
engine· running parameters. For instance, in each cycle, the disk (94a) facilitates
communication between the between the cylinder bore (14) and upto the primary
controlling means (92) in the passageway (24). Further, the electronic control unit (C) is
configured to receive the information relating to engine running parameter(s), where the
engine running parameters includes at least one from among the engine temperature, the
engine RPM, the engine load, information of knocking of the engine, etc. In an
embodiment, one or more sensor( s) can be used to detect such engine running
parameters. In an embodiment, the electronic control unit (C) is equipped with the
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IPO DELHI G2-B9-201S 17 12
intelligence to determine, based on the engme runnmg parameter, whether the
compression of the engine (E) is to be decreased or not. When the Electronic control unit
(C) determines that compression of the engine (E) should be decreased, it actuates the
valve operating means (98) such as electric motor to open the primary controlling means
(92) i.e. valve.
[0047] Thus, for example, when the engine (E) is running at lower load condition,
the elongated slot (96) of the disc (94a) overlaps with the bleeding port (18) but the
electronic control unit (C) does not open the primary controlling means (92) (e.g., valve)
at all, enabling the engine (E) to run at the higher dynamic compression ratio. However,
when the engine (E) is running at high load condition, the elongated slot (96) of the disc
(94a) overlaps with the bleeding port (18) and the electronic control unit (C) determines
that load on the engine (E) is beyond the particular load limit, and the electronic control
unit (C) operates the valve operating means (98) (e.g., the electric motor) to open the
primary controlling means (92) and to close the primary controlling means (92) after
estimated time period enabling the engine (E) to run at lower dynamic compression ratio.
Thus, the engine (E) is adapted to work with variable compression. The electronic
control unit (C) and the primary controlling means (92) can work in similar way as
mentioned in the earlier embodiment.
[0048] In an embodiment, the charge which is escaped from the cylinder bore ( 14)
through the passageway (24) is re-circulated into the· intake system (20). In an
embodiment, an auxiliary chamber (22) is provided between the passageway (24) and the
intake system (20). In an embodiment, a secondary controlling means (not shown in
Figures) (e.g., a valve) is disposed between the auxiliary chamber (22) and the intake
system (20). The secondary controlling means is controlled by the electronic control unit
(C). The electronic control unit (C) is adapted to open the secondary controlling means
during intake stroke of the engine (E). The secondary controlling means can be opened
and closed during the particular portion of the intake stroke. The secondary controlling
means is substantially similar to the primary controlling means (92) described above.
[0049] In another embodiment, the charge which is escaped from the cylinder bore
(14) through the passageway (24) is re-circulated into the intake system (20). In an
embodiment, the auxiliary chamber (22) is provided between the passageway (24) and
15
IPO DELHI 02-09-2015 17 12'
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the intake system (20). In an embodiment, the auxiliary chamber (22) can be filled by
suitable fuel adsorbing material, which adsorbs the fuel from the leaked charge from the
engine (E). In such implementation, the air can be vented_ off from the auxiliary chamber
(22), and the fuel can be released in the intake system (20) by mechanisms such as an
electrically controlled purge valve.
[0050] In another embodiment, the secondary controlling means is a secondary
rotary valve (100) (hereinafter referred to as secondary disc (100)) mounted to the
auxiliary shaft (28). The secondary disc (1 00) is adapted to open and close the
passageway (24) during the intake stroke of the engine (E). In an embodiment, the
secondary disc (1 00) comprises an elongated slot ( 1 03 ), and has configurations
substantially same as that of the disc (94a) described above.
[0051] Those skilled in the art would appreciate that by utilizing the auxiliary
chamber (22) and the secondary rotary valve (1 00), the charge I fuel escaped from the
cylinder bore (14) is re-circulated to the engine (E) in the subsequent cycles, and thereby
precluding any wastage of the fuel.
[0052] As stated in the foregoing description, various embodiments of the present
invention provide internal combustion engine having variable compression, wherein a
reduction for dynamic compression ratio at peak load can be achieved with minimum
and simple components. The present invention provides a simple arrangement and
system for the internal combustion engine having variable compression which can be
applied on any engine (e.g., spark ignition engine, diesel engine, or gaseous fuels based
engine) and requires a minimum of simple components and control only. This improves
overall efficiency in part load condition associated with the engine.
[0053) In various embodiments, the bleeding poJ;t is provided on the sidewall of the
cylinder block at a position which is at predetermined distance from the TDC, hence, the
bleeding port and the valve system provided in the bleeding port are not exposed to the
· high temperature during operation of the engine.
[0054] While few embodiments of the present invention have been described above,
it is to be understood that the invention is not limited to the above embodiments and
16
IPO DELHI 92~B9-2Bl5 17
modifications may be appropriately made ·thereto within the spirit and scope of the
invention.
lOOSS] While considerable emphasis has been placed herein on the particular features
of this invention, it will be appreciated that various modifications can be made, and that
many changes cim be made in the preferred embodiments without departing from the
principles of the invention. These and other modifications in the nature of the invention
or the preferred embodiments will be apparent to those skilled in the art from the
disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive
matter is to be interpreted merely as illustrative of the invention and not as a limitation.

CLAIMS
We claim:
1. A four stroke internal combustion engine of a vehicle, the four stroke internal
combustion engine comprising:·
a cylinder block comprising a cylinder bore;
a bleeding port provided on a wall of the cylinder bore, the bleeding port fluidly
connecting the cylinder bore to a passageway; and
a primary controlling means provided to the bleeding port· to control opening
and closing. of the passageway during a compression stroke of the four stroke ·internal
combustion engine based on one or more engine running parameters associated with the
vehicle for controlling a fluidic communication between the cylinder bore and the
passageway, wherein controlling the fluidic communication enables varying an amount
of charge present in the cylinder bore during the compression stroke.
2. The four stroke internal combustion engine as claimed in claim 1, wherein the
primary controlling means comprises one or more valves, and wherein the four stroke
internal combustion engine further comprises:
a control unit configured to access the one or more engine running parameters
and generate a signal cotTesponding to the one or more accessed engine running
parameters; and
a valve operating means for controlling opening and closing of the one or more
valves based 01;1 the signal received from the control unit.
3. The four stroke internal combustion engine as claimed in claim 2, wherein the
one. or more valves comprises at least one of a rotary valve, a puppet valve and a
solenoid valve.
4. The four stroke internal combustion engine as claimed in claim 2, wherein the
valve operating means is an electric motor operated by the control unit.
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IPO DELHI 92-99-2015 17
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5. The four stroke internal combustion engine as claimed in claim 2, wherein the
one or more engine running parameters comprises at leasl one of an engine temperature,
an engine revolution per minute (RPM), an engine load and an information of knocking
of the four stroke internal combustion engine.
6. The four stroke internal combustion engine as claimed in claim 2, wherein the
primary controlling means is a combination of two or more valves connected in series in
the passageway.
7. The four stroke internal combustion engine as claimed in claim 2, wherein the
control unit. is configured to, based on intensity of the one or more engine running
parameters, actuate the valve operating means to open the primary controlling means for
an estimated time period and with a specified degree of opening in the compression
stroke.
8. The four stroke internal combustion engine as claimed in any of claims I to 7,
further comprising a rotary valve for controlling opening and closing of the bleeding
port during the compression stroke of the four stroke internal combustion engine.
9. The fourstroke internal combustion engine as claimed in claim 8, wherein the
rotary valve is fixedly mounted to an auxiliary shaft being rotated by a crankshaft via an
auxiliary timing transmission device, wherein the crankshaft is housed in a crankcase,
wherein the four stroke internal combustion engine further comprises a piston
reciprocatingly movable in the cylinder bore and connected to the crankshaft by a
connecting rod.
I 0. The four stroke internal combustion engine as claimed in claim 9, wherein the
bleeding port is provided at an intermediate position between a top dead centre (TDC)
and a bottom dead centre (BDC) of the piston in the cylinder bore.
19
IPO DELHI 92-09-2015 11 12
11. The four stroke internal combustion engine as claimed in claim 8, wherein the
rotary valve is fixedly mounted to an auxiliary shaft being rotated by a camshaft via an
auxiliary timing transmission device, wherein the camshaft is rotatably supported on a
cylinder head of the four stroke internal combustion engine, and wherein the camshaft is
operatively configured to open and close each of an intake valve and an exhaust valve
of the four stroke internal combustion engine .
. 12. The four stroke internal combustion engme as claimed in claims 9 or 11,
wherein the rotary valve is a disc comprising an elongated slot therethrough, the
elongated slot being an arc shaped opening positioned at a radial distance from an axis
of the auxiliary shaft, and wherein when the elongated slot overlaps with the bleeding
port, the fluidic communication is maintained between the cylinder block and upto the
primary controlling means in the passageway.
13. The four stroke internal combustion engine as claimed in any of claims 1 to 12,
wherein the passageway is connected to an intake system of the four stroke internal
combustion engine, and wherein charge escaped from the cylinder bore through the
passageway is re-circulated into the intake system.
14. The four stroke internal combustion engine as claimed in claim 13, further
comprising an auxiliary chamber configured between the passageway and the intake
system.
· 15. The four stroke internal combustion engine as claimed in claim 14, further
comprising a secondary controlling means disposed between the auxiliary chamber and
the intake system;· wherein· the secondary controlling means is controlled by a control
unit, wherein the control unit is configured to open the secondary controlling means
during an intake stroke of the four stroke internal combustion engine.
16. The four stroke internal combustion engine as claimed in claim 14, wherein the
auxiliary chamber is filled with a fuel adsorbing material.