DESC:TECHNICAL FIELD
[0001] The present subject matter relates generally to an internal combustion engine of a vehicle. More particularly but not exclusively, the present subject matter relates to an auto decompression system capable of performing decompression.
BACKGROUND
[0002] Generally, an internal combustion engine is functionally connected to a rear
wheel of a vehicle to provide a forward motion to it. The internal combustion engine comprises a cylinder bore or a combustion chamber where the combustion occurs to provide the needed power for the forward motion of the vehicle. The internal combustion (IC) engine, among other components, has a cylinder on top of which a cylinder head is mounted, and receives a reciprocating piston from the bottom. On combustion of the air-fuel mixture, the piston transfers the energy generated during combustion to a crankshaft through a connecting rod thereby driving the crankshaft. In this way, the reciprocal motion of the piston is converted to the rotary motion of the crankshaft. The crankshaft rotation then in turn powers the vehicle. For easy starting or cranking of the engine decompression mechanism is used, which reduces the pressure of the air-fuel mixture in the combustion chamber by releasing an amount of the mixture to the exhaust system. The compression is reduced by momentarily opening an exhaust valve on the compression stroke of the piston to partially vent the combustion chamber. Reducing the engine compression reduces the force required to kick start or pull start the engine and allows the use of smaller less powerful electric starting components.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is described with reference to system of an auto decompression for an exemplary embodiment of an engine of a vehicle along with the accompanying drawings. The same numbers are used throughout the drawings to refer to similar features and components.
[0003] Fig 1 exemplarily illustrates a exemplarily illustrates a plain enlarged view of right side of a cylinder of the internal combustion engine (100) in accordance with an embodiment of the present subject matter.
[0004]
[0005] Fig 2 exemplarily illustrates a block diagram of the auto decompression system in accordance with an embodiment of the present subject matter
[0006]
[0007] Fig 3 exemplarily illustrates a flow chart of the method of auto decompression system in accordance with an embodiment of the present subject matter.

DETAILED DESCRIPTION
[0008] Generally, the internal combustion engine is the power unit of the vehicle enabled to provide the required drive. Typically, the internal combustion engine is coupled to the drive wheel, which is generally the rear wheel. Mostly, the internal combustion engine comprises a cylinder bore where the combustion occurs to provide the needed power for the forward motion of the vehicle. The internal combustion (IC) engine, among other components, comprises a cylinder on top of which a cylinder head is mounted. The cylinder head is mounted to accommodate and receive the to-and-fro motion of the piston reciprocating from the bottom in an upward direction. On combustion of the air-fuel mixture, the piston transfers the energy generated during combustion to a crankshaft through a connecting rod thereby driving the crankshaft. In this way, the reciprocating motion of the piston is converted to the rotary motion of the crankshaft which in turn powers the vehicle.
[0009] The internal combustion engine comprises of an inlet port and an exhaust port formed in the cylinder head through which air-fuel mixture is sent in and after combustion, the exhaust is sent out. The internal combustion engine comprises an inlet valve and exhaust valve to control the opening and closing of the passage of the exhaust port and inlet port. The opening and closing of the exhaust valve and the inlet valve are based on the kind of stroke occurring in the engine, whether it is an intake stroke, compression stroke, power stroke, or an exhaust stroke. The engines are provided with one spark plug which forms an integral part of the internal combustion engine and develops a spark. The spark developed in the combustion chamber of the internal combustion engine ignites the air-fuel mixture and develops the required power.
[00010] The internal combustion engine cycle begins with the intake stroke as the piston is pulled towards a crankshaft. In intake stroke, the inlet valve is open, through which air-fuel mixture is drawn past the valve into the combustion chamber through the inlet port located on top of the combustion chamber. For the intake stroke, the exhaust valve is closed and the electrical contact switch is open. At the end of the intake stroke, the piston is located at the bottom dead center (BDC) and begins to move back towards the top dead center (TDC). The combustion chamber is full of the low-pressure air-fuel mixture and, as the piston begins to move to the TDC, the intake valve closes.
[00011] In furtherance to it, next is a compression stroke in which both the inlet valve and exhaust valve are closed and the cylinder and combustion chamber form
a completely closed vessel and contain the fuel/air mixture. As the piston is pushed to the TDC, the volume is reduced, and the air-fuel mixture is compressed during the compression stroke. However, no heat is transferred to the air-fuel mixture during the compression stroke. As the volume is decreased because of the piston's motion, the pressure in the gas is increased, as described by the laws of thermodynamics. During the compression stroke, the electrical contact for the spark plug is kept open.
[00012] After the compression stroke engine processes a power stroke, in which the electrical contact is opened. When the volume is the smallest, and the pressure the highest, the contact is closed, and a current of electricity flows through the spark plug. The sudden closing of the contact produces a spark in the combustion chamber which ignites the air-fuel mixture. Rapid combustion of the fuel releases heat and produces exhaust gases in the combustion chamber. Because the inlet and exhaust valves are closed, the combustion of the fuel takes place in an enclosed vessel. The combustion increases the temperature of the exhaust gases, any residual air in the combustion chamber, and the combustion chamber itself. From the ideal gas law, the increased temperature of the gases also produces an increased pressure in the combustion chamber. The high pressure of the gases acting on the face of the piston causes the piston to move to the BDC which initiates the power stroke. Unlike the compression stroke, the hot gas does work on the piston during the power stroke. The force on the piston is transmitted by the piston rod to the crankshaft, where the linear motion of the piston is converted to the rotational motion of the crankshaft. The work done on the piston is then used to turn a crankshaft in the cylinder's compression stroke. Having produced the igniting spark, the electrical contact remains closed.
[00013] For easy starting or cranking of the engine decompression mechanism is used, which reduces the pressure of the air-fuel mixture in the combustion chamber by releasing an amount of the mixture to the exhaust system. The compression is reduced by momentarily opening an exhaust valve on the compression stroke of the piston to partially vent the combustion chamber when the speed of the engine is less example around 400 to 800 rpm which is achieved while kick start or pull starting the engine. Reducing the engine compression reduces the force required to kick start or pull start the engine and allows the use of smaller less powerful electric starting components. The quantity of air-fuel mixture released, and the final compression pressure completely depends upon existing compression pressure, which in turn depends on the quantity of residual fuel mixture and fresh fuel mixture intake. The quantity of residual fuel mixture in the engine is inconsistent for every stop-start cycle of the vehicle, due to which the quantity of fuel mixture released, and the final compression pressure is also inconsistent. During starting, final compression pressure is critical as it decides the cranking speed and torque, which in turn affects the cranking current required to power the engine by the starter motor. In few cases said engine cranks at a higher load, resulting in high cranking current and speed which are excessive than ideal values, and in some conditions, the engine cranks at lower load, resulting in low cranking current and speed which are insufficient to ideal values as a result which does not allow the engine to start easily. Excess high pressure in the chamber would need high power and big starter motor and high-power battery to provide sufficient cranking current which would eventually increase the cost of the vehicle manufacturing, weight, and maintenance complexity. Even though decompression is aiding in the cranking process, the amount of fuel mixture released through decompression is inconsistent as decompression mechanism is based on engine speed and centrifugal force being generated.
[00014] As per known art, the pressure of the chamber is released by a pressure release valve which needs manual intervention by the user during cranking of the system and after cranking the user must close the said valve. However, such a system releases the fuel mixture for lowering pressure even during the power stroke of the engine, which is undesirable as this will affect the overall efficiency of the engine. The decompression is desirable only for cranking the engine.
[00015] As per yet another known art, the fuel mixture is released through a compression relief valve provided in the combustion chamber, and the valve is actuated using a hydraulic system. The system is complex, and it releases fuel mixture during power stroke also which can result in emission because an amount of unburnt fuel is being released unnecessarily thus, reducing fuel efficiency economically. The condition under which the compression relief valve will be operated is not certain.
[00016] Therefore, a system should be designed that can help in achieving consistency of auto decompression as per the requirement of the engine working condition and attaining ideal cranking speed and torque values in an efficient, and simple manner. A system that can provide and maintain a consistent fuel mixture in the engine for easy cranking of the engine is desirable. A system capable of achieving optimum air-fuel mixture in the engine which is sufficient to crank the engine in a minimum attempt and easier to compress with minimum energy required for the efficient functioning of the vehicle is desirable.
[00017] Taking note of the above, it is an object of the present invention to provide an engine of a vehicle that can achieve optimum air-fuel mixture which is sufficient to crank the engine in a minimum attempt and easier to compress with minimum energy required for the efficient functioning of the vehicle.
[00018] Another object of the present invention is to provide an auto decompression system that can ensure consistency of the amount of fuel mixture in the engine for easy cranking and efficient operation of the vehicle.
[00019] It is yet another object of the present invention to prove a method of auto decompression mechanism in an engine of a vehicle.
[00020] It is yet another object of the present invention to provide a pressure release valve that works on the predetermined parameter of the combustion chamber based upon an electronic power supply for the auto decompression system of the vehicle.
[00021] It is another object of the present invention to provide an auto decompression system that will maintain the efficiency of the vehicle during the power cycle of the engine.
[00022] It is another object of the present invention to provide an auto decompression system that will not unwantedly contribute to the emission of fuel.
[00023] Hence, the present invention provides a method of auto decompression of an engine of a vehicle, the method comprising the steps of verifying power key status of the vehicle is in active mode; If the power key status is in active mode then verifying start switch status of the vehicle is active mode. If the start switch is in active mode, then, the controller examines the status of engine cranking. Then the control unit activates a pressure release valve if the engine cranking position is deactivated i.e. if the engine has not yet cranked. The control unit deactivates the pressure release valve if the engine crank status is active meaning the engine has already cranked.
[00024] As per an aspect of the present invention, the activating step of the pressure release valve wherein the pressure release valve comprises a solenoid which when powered is configured to compress and decompress a spring based upon a predetermined parameter of the combustion chamber exceeds a threshold value.
[00025] As per an aspect of the present invention, wherein the activating step, the pressure release valve is closed by decompressing the spring by said solenoid when the predetermined parameter of the combustion chamber is less than the threshold value.
[00026] As per an aspect of the present invention wherein, the activating step the pressure release valve is opened by compressing the spring by said solenoid when the predetermined parameter of the combustion chamber exceeds the threshold value.
[00027] As per an aspect of the present invention, the predetermined parameter of the combustion chamber is the compression pressure of fuel mixture.
[00028] As per an aspect of the present invention the deactivating step, the pressure release valve is deactivated in the power cycle of the engine.
[00029] As per an embodiment of the present invention an auto decompression system for a two-wheeled vehicle, the two-wheeled vehicle comprises a combustion chamber comprising a cylinder to accommodate a reciprocating piston for combustion of fuel; a cylinder head disposed of over said cylinder block to receive said reciprocation piston; an inlet port formed on the said cylinder head to allow entry of air-fuel mixture in said internal combustion engine; an exhaust port formed on the said cylinder head to allow exhaust formed after combustion to leave said internal combustion engine; a pressure release valve and an inlet valve disposed of in said cylinder head enabling opening and closing of the said exhaust port and said inlet port;
wherein a control unit activates and deactivates the pressure release valve comprising a solenoid based upon the cranking position of the engine and power cycle of said engine.
[00030] As per an aspect of the present invention, the auto decompression system the pressure release valve comprises a solenoid; and a spring; wherein activating the pressure release valve powers said solenoid which is configured to compress and decompress said spring based upon a predetermined parameter of the combustion chamber.
[00031] As per an aspect of the present invention, wherein in the activating step, the pressure release valve is closed by decompressing the spring by said solenoid when the predetermined parameter of the combustion chamber is less than the threshold value.
[00032] As per an aspect of the present invention, in the activating step, the pressure release valve is opened by compressing the spring by said solenoid when the predetermined parameter of the combustion chamber exceeds the threshold value.
[00033] As per an embodiment of the present invention the control unit is a vehicle control unit.
[00034] The present subject matter is further described with reference to the accompanying figures. It should be noted that the description and figures merely illustrate the principles of the present subject matter. Various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof.
[00035] The foregoing disclosure is not intended to limit the present disclosure to the precise forms or fields of use disclosed. As such, it is contemplated that various alternate embodiments and/or modifications to the present disclosure, whether explicitly described or implied herein, are possible considering the disclosure. Having thus described embodiments of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made in form and detail without departing from the scope of the present disclosure. Thus, the present disclosure is limited only by the claims.
[00036] Accordingly, this description is to be considered as illustrative and is for the purpose of teaching those skilled in the art the manner of making and using various embodiments of the disclosure. It is to be understood that the forms of the disclosure herein shown and described are to be taken as representative embodiments. Equivalent elements, materials, processes, or steps may be substituted for those representatively illustrated and described herein. Moreover, certain features of the disclosure may be utilized independently of the use of other features, all as would be apparent to one skilled in the art after having the benefit of this description of the disclosure. Expressions such as “including”, “comprising”, “incorporating”, “consisting of”, “have”, “is” used to describe, and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural.
[00037] Further, various embodiments disclosed herein are to be taken in the illustrative and explanatory sense and should in no way be construed as limiting of the present disclosure. All joinder references (e.g., attached, affixed, coupled, connected, etc.) are only used to aid the reader's understanding of the present disclosure, and may not create limitations, particularly as to the position, orientation, or use of the systems and/or methods disclosed herein. Therefore, joinder references, if any, are to be construed broadly. Moreover, such joinder references do not necessarily infer those two elements are directly connected to each other.
[00038] Additionally, all numerical terms, such as, but not limited to, “first”, “second”, “third”, “primary”, “secondary”, “main” or any other ordinary and/or numerical terms, should also be taken only as identifiers, to assist the reader's understanding of the various elements, embodiments, variations and/or modifications of the present disclosure, and may not create any limitations, particularly as to the order, or preference, of any element, embodiment, variation and/or modification relative to, or over, another element, embodiment, variation and/or modification. In addition, it is to be understood that the phraseology and terminology used herein is for description and should not be regarded as limiting.
[00039] It will also be appreciated that one or more of the elements depicted in the drawings/figures can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful in accordance with a particular application. Additionally, any signal hatches in the drawings/figures should be considered only as exemplary, and not limiting, unless otherwise specifically specified.
[00040] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
[00041] Fig 1. exemplarily illustrates a plain enlarged view of the right side of a cylinder of the internal combustion engine (100) in accordance with an embodiment of the present subject matter. Generally, the internal combustion engine (100) comprises a cylinder block (102) which accommodates a reciprocating piston (104), and a cylinder head (106) where the combustion of the air-fuel mixture occurs. In furtherance to it, a carburetor (not shown) is also provided which supplies the air-fuel mixture to the internal combustion engine (100). The cylinder head (106) comprises of an inlet port (106aa) through which the air-fuel mixture enters the internal combustion engine (100) and an exhaust port (106bb) through which the exhaust generated after combustion leaves the internal combustion engine (100). The cylinder block (102) accommodates the piston (104) with its reciprocating motion, such that the motion of the piston (104) is converted into the rotational motion of the crankshaft (not shown). The cylinder head (106) is provided with an exhaust valve (106b) and inlet valve (106a) which controls the opening and closing of the exhaust port (106bb) and inlet port (106aa). For easy starting or cranking of the engine (100), a decompression mechanism is used, which reduces the pressure of the air-fuel mixture in a combustion chamber (108) during compression stroke by releasing an amount of the mixture to the exhaust system (not shown). Conventionally, the compression is reduced by momentarily opening an exhaust valve (106b) on the compression stroke of the piston to partially vent the combustion chamber when the speed of the engine (100) is less for example around 400 to 800 rpm which is achieved while kick start or pull starting the engine (100). Reducing the engine (100) compression pressure reduces the force required to kick start or pull start the engine (100) and allows the use of smaller less powerful electric starting components. The quantity of air-fuel mixture released, and the final compression pressure completely depends upon existing compression pressure, which in turn depends on the quantity of residual fuel mixture and fresh fuel mixture intake. During starting, final compression pressure is critical as it decides the cranking speed and torque, which in turn affects the cranking current required to power the engine (100) by the starter motor.
[00042] Fig 2. exemplarily illustrates a block diagram of the auto decompression system in accordance with an embodiment of the present subject matter. The vehicle is switched on or activated by an ignition switch (202) which is powered by a power source (200). Once the ignition switch is ON, the electric start, and brake switch (204,206) is activated for engine cranking. The status of the ignition switch, electric start, and brake switch (202, 204,206) is monitored by a vehicle control unit (212). A starter motor (214) that gets a power supply from the power source (200) supplies power to the engine (216) to get started or cranked. The status of the engine (216) such as its cranking position, the status of the piston, i.e., the stroke in which it is operating is continuously monitored by the vehicle control unit (212) or a TCI unit (not shown) which is mounted on mount the TCI unit on the head tube (not shown) by using a bracket or any other mounting means (not shown). A pressure release valve (218) is coupled with the engine (216) which releases the pressure upon getting activated by a control unit (220). The control unit (220) gets the status update of the engine (216) from the vehicle control unit (212). Therefore, when the control unit (220) receives a signal about the activation of the ignition switch and electric start, along with the cycle of the engine (216) operation, then said control unit (220) powers the pressure release valve (218) which activates the said pressure release valve (218). Once the pressure release valve (218) is activated it closes and opens as per the predetermined parameter of the combustion chamber. The predetermined parameter of the combustion chamber as per an embodiment is the compression pressure of the fuel at compression stroke.
[00043] The pressure release valve (218) can be operated mechanically by several principles. As per an embodiment, the pressure release valve (218) comprises a solenoid (not shown) and a spring (not shown). The activation of the pressure release valve (218) activates the solenoid, which is configured to set the spring load by pulling/pushing the spring using magnetic force such that the spring can be compressed only if compression pressure is greater than pre-set value. On compressing the spring, the pressure release valve (218) opens while on decompression pressure release valve (218) closes. Once the compression pressure becomes less than the pre-set pressure, the valve will be closed. On powering off the pressure relief valve (218), it deactivates solenoid thereby the spring resets to its default position which can be set at the installation phase such that spring load is more than the compression load in all engine working conditions. So, the spring remains uncompressed, and the pressure relief valve (218) will be closed always. The pre-set pressure value is determined by several trials such that it can help in attaining ideal rpm and torque values.
[00044] As per an embodiment of the present invention, the pressure relief valve (218), is an exhaust valve (106b, shown in Fig.1).
[00045] As per an embodiment the control unit (220) is the vehicle control unit (212) which activated or deactivate the pressure release valve (218).
[00046] Fig 3. exemplarily illustrates a flow chart of the method of auto decompression system in accordance with an embodiment of the present subject matter. The method comprises the steps of starting the vehicle at step 300. The ignition key or switch is switched ON at step 302, followed by an electric start switch at step 304. If both the switches at step 302 and 304 are ON, then the vehicle control unit (212) examines the cranking position of the engine (216) at step 306. If the engine (216) is cranked, then the cranking process by cycling the engine (216) in four strokes gets initiated, and the pressure release valve (218) gets powered by the control unit (220) at step 308. In case the compression pressure is more than the pre-set value at step 310, then the pressure release valve (218) will be opened as per step 312. However, in case the compression pressure is less than the pre-set value at step 310, the pressure release valve (218) will be closed or remain in closed condition as per step 314. If the engine (216) comes in power stroke before the engine (216) is cranked or the engine (216) has already cranked at step 316, then the pressure release valve (218) will be deactivated as per step 318 by switching off the power supply to the pressure release valve (218). After the engine (216) has already cranked the pressure release valve (218) gets deactivated for further working conditions of the engine in the same cycle.
[00047] It is to be understood that the aspects of the embodiments are not necessarily limited to the features described herein. Many modifications and variations of the present subject matter are possible in light of the above disclosure. Therefore, within the scope of claims of the present subject matter, the present disclosure may be practiced other than as specifically described.

List of Reference numerals
100: Engine 108: Combustion chamber
102: Cylinder block 200-220: Block diagram
104: Piston 300-320: Flow chart
106: Cylinder head
106a: Inlet valve
106b: Exhaust valve
106aa: Inlet port
106bb: Exhaust port
,CLAIMS:We claim:
1. A method of auto decompression of an engine (216) of a vehicle, the method comprising the steps of:
verifying ignition key (202) status of the vehicle being in active mode at step 302;
verifying start switch (204) status of the vehicle being in active mode; at step 304
examining the status of an engine (216) crank by a control unit (220) at step 306;
activating a pressure release valve (218) by the control unit (220) if the engine (216) cranking position being deactivated at step 308;
deactivating the pressure release valve (218) by the control unit (220) when the engine (216) crank status being active at step 318.
2. The method as claimed in claim 1, wherein the activating step of the pressure release valve (218) comprising a solenoid being powered, wherein the solenoid being configured to compress and decompress a spring when a predetermined parameter of the combustion chamber exceeds a threshold value.
3. The method as claimed in claim 1 and claim 2, wherein the activating step of the pressure release valve (218) being closed by decompressing the spring by said solenoid when the predetermined parameter of the combustion chamber being less than the threshold value.
4. The method as claimed in claim 1 and 2, wherein the activating step of the pressure release valve (218) being opened by compressing the spring by said solenoid when the predetermined parameter of the combustion chamber exceeds the threshold value.
5. The method as claimed in claim 2 and claim 3, wherein the predetermined parameter of the combustion chamber being the compression pressure of air fuel mixture.
6. The method as claimed in claim 1, wherein the deactivating step, the pressure release valve (218) being deactivated in the power cycle of the engine (216).
7. An auto decompression system for a two wheeled vehicle, the two wheeled vehicle comprising:
a combustion chamber comprising a cylinder to accommodate a reciprocating piston for combustion of fuel;
a cylinder head disposed over said cylinder block to receive said
reciprocation piston;
an inlet port formed on said cylinder head to allow entry of air fuel
mixture in said internal combustion engine (216);
an exhaust port formed on said cylinder head to allow exhaust formed after combustion to leave said internal combustion engine (216);
a pressure release valve (218) and an inlet valve disposed in said cylinder head enabling opening and closing of said exhaust port and said inlet port;
wherein a control unit (220) activates and deactivates the pressure release valve (218) based upon cranking position of the engine (216) and power cycle of said engine (216).
8. The auto decompression system as claimed in claim 7, wherein the pressure release valve (218) comprises:
a solenoid; and
a spring;
wherein activating of the pressure release valve (218) powers said solenoid wherein the solenoid being configured to compress and decompress said spring based upon predetermined parameter of the combustion chamber.
9. The auto decompression system as claimed in claim 7, wherein the activating step of the pressure release valve (218) being closed by decompressing the spring by said solenoid when the predetermined parameter of the combustion chamber being less than the threshold value.
10. The auto decompression system as claimed in claim 7, wherein the activating step of the pressure release valve (218) being opened by compressing the spring by said solenoid when the predetermined parameter of the combustion chamber exceeds the threshold value.
11. The auto decompression system as claimed in claim 7, wherein the control unit (220) being a vehicle control unit (212).