DESC:TECHNICAL FIELD
[001] The embodiments herein generally relate to engines in vehicles and more particularly, but not exclusively to compressed natural gas (CNG) engine in vehicles.

BACKGROUND
[002] Conventional vehicles generally use gasoline/diesel as a fuel for powering an engine. As a result of combustion in the engine, harmful emissions from the engine are emitted into the atmosphere thereby causing air pollution. The harmful emissions of the engine contain carbon di-oxide (CO2), a primary greenhouse gas that tends to trap heat in the atmosphere thereby causing global warming. In addition, the harmful emissions also have adverse effects on living things and environment. Owing to stringent emission norms and limited availability of fossil fuels, demand for improving fuel efficiency and reduction of harmful emission has become the prime concern. Further, the combustion system in the engine of the aforementioned vehicles is subjected to irregular combustion thereby leading to lower power output of the engine.
[003] Therefore, there exists a need for an efficient engine for a vehicle that can use alternate fuels to reduce harmful emission into the atmosphere.

OBJECTS
[004] The principal object of an embodiment of this invention is to provide a compressed natural gas (CNG) engine for a vehicle, which has reduced emission levels.
[005] Another object of an embodiment of this invention is to provide a compressed natural gas (CNG) engine for a vehicle, which has better combustion efficiency and high thermal efficiency.
[006] These and other objects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF DRAWINGS
[007] The embodiments of the invention are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[008] FIG. 1 depicts a cross-sectional view of a portion of an engine, according to an embodiment of the invention as disclosed herein;
[009] FIG. 2 depicts a cross-sectional view of a piston of the engine, according to an embodiment of the invention as disclosed herein;
[0010] FIG. 3 depicts a top view of a cylinder head of the engine, according to an embodiment of the invention as disclosed herein; and
[0011] FIG. 4 depicts a front view of an intake manifold of the engine, according to an embodiment of the invention as disclosed herein.

DETAILED DESCRIPTION
[0012] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0013] The embodiments herein achieve a compressed natural gas (CNG) engine for a vehicle, which has reduced emission levels. Further, embodiments herein achieve a compressed natural gas (CNG) engine for a vehicle, which has better combustion efficiency and high thermal efficiency. Referring now to the drawings, and more particularly to FIGS. 1 through 4, where similar reference characters denote corresponding features consistently throughout the figures there are shown embodiments.
[0014] FIG. 1 depicts a cross-sectional view of a portion of an engine 10, according to an embodiment of the invention as disclosed herein. In an embodiment, the engine 10 includes a combustion system 100, at least one intake camshaft (not shown), at least one exhaust camshaft (not shown), at least one intake manifold 110 (as shown in fig. 4) and may include other standard components used in the standard compressed natural gas engine. In an embodiment, the engine 10 is a naturally aspirated compressed natural gas (‘hereinafter CNG’) direct injection engine. In another embodiment, the engine 10 is a turbocharged CNG direct injection engine. In another embodiment, the engine 10 is a naturally aspirated CNG engine. In an embodiment, compression ratio of the naturally aspirated CNG direct injection engine 10 is 14:1. In another embodiment, the compression ratio of the naturally aspirated CNG direct injection engine 10 is in the range of 12:1 to 15:1. In an embodiment, compression ratio of the turbocharged CNG direct injection engine 10 is 13.5:1. In another embodiment, compression ratio of the turbocharged CNG direct injection engine 10 is in the range of 12:1 to 15:1. In an embodiment, compression ratio of the naturally aspirated CNG engine 10 is 12:1. In another embodiment, compression ratio of the naturally aspirated CNG engine 10 is in the range of 11:1 to 13:1. In an embodiment, the engine 10 can be configured to use natural gases such as bio-CNG, liquefied natural gas (LNG), hydrogen, liquefied petroleum gas (LPG) and the like, as a fuel. However, it is also within the scope of the invention to configure the engine 10 to use any other type of fuels without otherwise deterring the intended function of the engine 10 as can be deduced from the description.
[0015] In an embodiment, the combustion system 100 includes at least one piston 102 (as shown in fig. 1 and fig. 2), at least one fuel injector 104, at least one spark plug 106, at least one cylinder head 108 (as shown in fig. 1 and fig. 3), at least one intake valve (not shown), at least one exhaust valve (not shown), at least one cylinder (not shown) and may include other standard components used in standard CNG engine.
[0016] The piston 102 reciprocates inside the cylinder (not shown) of the engine 10 during the operation of the engine 10. In an embodiment, the piston 102 is configured to provide greater squish area thereby enabling effective mixing of air and fuel. In an embodiment, bowl diameter of the piston 102 is 68 mm. In another embodiment, bowl diameter of the piston 102 is in the range of 60 mm to 75 mm. It is also within the scope of the invention to provide any other bowl diameter dimensions for the piston 102. In an embodiment, bowl depth of the piston 102 is 14.3 mm for naturally aspirated CNG direct injection engine 10. In another embodiment, bowl depth of the piston 102 is in the range of 12 mm to 18 mm for naturally aspirated CNG direct injection engine 10. In an embodiment, the bowl depth of the piston 102 is 15.32 mm for turbocharged CNG direct injection engine 10. In another embodiment, bowl depth of the piston 102 is in the range of 13 mm to 17 mm for turbocharged CNG direct injection engine 10. It is also within the scope of the invention to provide any other bowl depth dimensions for the piston 102. In an embodiment, bowl angle of the piston 102 is 60 degree. In another embodiment, bowl angle of the piston 102 is in the range of 45 degree to 70 degree. It is also within the scope of the invention to provide any other bowl angles for the piston 102.
[0017] The fuel injector 104 is used to inject fuel into the cylinder (not shown) of the engine 10. In an embodiment, the fuel injector 104 is provided to at least one first cavity 108a of the cylinder head 108 at 24 degree from a longitudinal plane P of the cylinder head 108 thereby facilitating effective mixing of the air and fuel. In another embodiment, the fuel injector 104 is provided to the first cavity 108a of the cylinder head 108 at the angle ranging from 10 degree to 30 degree from the longitudinal plane P of the cylinder head 108 thereby facilitating effective mixing of the air and fuel. In an embodiment, the fuel injector 104 includes a portion 104a and may include other standard elements as present in standard fuel injector. The portion 104a of the fuel injector 104 is configured to facilitate effective mixing of fuel and air. In an embodiment, the distance between the portion 104a of the fuel injector 104 and the horizontal plane P of the cylinder head 108 is 26.6 mm. In another embodiment, the distance between the portion 104a of the fuel injector 104 and the horizontal plane P of the cylinder head 108 is in the range of 22 mm to 30 mm. It is also within the scope of the invention to provide any other range of distance between the portion 104a of the fuel injector 104 and the horizontal plane P of the cylinder head 108.
[0018] The spark plug 106 is used to ignite the air-fuel mixture in the cylinder (not shown) of the engine 10. In an embodiment, the spark plug 106 is provided to at least one second cavity 108b of the cylinder head 108 at 15 degree from the longitudinal plane P of the cylinder head 108. In another embodiment, the spark plug 106 is provided to the second cavity 108b of the cylinder head 108 at the angle ranging from 0 degree to 20 degree from the longitudinal plane P of the cylinder head 108. In an embodiment, the angle between the spark plug 106 and the fuel injector 104 is 9 degree. In another embodiment, the angle between the spark plug 106 and the fuel injector 104 is in the range of 5 degree to 18 degree. In an embodiment, the spark plug 106 is M12 spark plug. However, it is also within the scope of the invention to provide any other type of spark plugs without otherwise deterring the intended function of the spark plug 106 as can be deduced from the description. In an embodiment, the spark plug 106 includes a portion 106a and may include other standard elements as present in standard spark plug. In an embodiment, the portion 106a of the spark plug 106 is configured to be exposed to a portion (not shown) of at least one combustion chamber (not shown) of the engine 10 thereby enabling better combustion. In an embodiment, the distance between the portion 106a of the spark plug 106 and the horizontal plane P of the cylinder head 106 is 7.4 mm. In another embodiment, the distance between the portion 106a of the spark plug 106 and the horizontal plane P of the cylinder head 106 is in the range of 2 mm to 15 mm. It is also within the scope of the invention to provide any other range of distance between the portion 106a of the spark plug 106 and the longitudinal plane P of the cylinder head 108. In an embodiment, the distance between the portion 106a of the spark plug 106 and the portion 104a of the fuel injector 104 is 19.98 mm. In another embodiment, the distance between the portion 106a of the spark plug 106 and the portion 104a of the fuel injector 104 is in the range of 10 mm to 25 mm. It is also within the scope of the invention to provide any other range of distance between the portion 106a of the spark plug 106 and the portion 104a of the fuel injector 104.
[0019] The cylinder head 108 includes at least one first cavity 108a, at least one second cavity 108b, at least one first seat 108c, at least one second seat 108d, a longitudinal plane P and may include other standard elements as present in standard CNG cylinder head. In an embodiment, the first cavity 108a of the cylinder head 108 is used to receive the fuel injector 104. In an embodiment, the second cavity 108b of the cylinder head 108 is used to receive the spark plug 106. In an embodiment, the first seat 108c of the cylinder head 108 is used to facilitate seating for a portion (not shown) of the fuel injector 104. In an embodiment, the second seat 108d of the cylinder head 108 is used to facilitate seating for a portion (not shown) of the spark plug 106.
[0020] The intake valve (not shown) is operated by the intake camshaft (not shown) to regulate the flow of air to the cylinder (not shown) of the engine 10. In an embodiment, hardness value of the intake valve seat (not shown) is 80 HRA. In another embodiment, the hardness value of the intake valve seat (not shown) is in the range of 60 HRA to 100 HRA. It is also within the scope of the invention to provide any other range of hardness value for the intake valve seat.
[0021] The exhaust valve (not shown) is operated by the exhaust camshaft (not shown) to facilitate discharge of exhaust gas from the cylinder (not shown) of the engine 10. In an embodiment, hardness value of exhaust valve seat (not shown) is 80 HRA. In another embodiment, the hardness value of the exhaust valve seat (not shown) is in the range of 60 HRA to 100 HRA. It is also within the scope of the invention to provide any other range of hardness value for the exhaust valve seat.
[0022] The intake camshaft (not shown) is used to operate at least one intake valve (not shown) of the engine 10. The exhaust camshaft (not shown) is used to operate at least one exhaust valve (not shown) of the engine 10. In an embodiment, the intake camshaft (not shown) is adapted to facilitate opening of the intake valve (not shown) 10 degree before a base camshaft intake valve opening timing and the exhaust camshaft (not shown) adapted to facilitate closing of the exhaust valve (not shown) at a base camshaft exhaust valve closing timing. In another embodiment, the intake camshaft (not shown) is adapted to facilitate opening of the intake valve (not shown) 10 degree before the base camshaft intake valve opening timing and the exhaust camshaft (not shown) adapted to facilitate closing of the exhaust valve (not shown) 10 degree after the base camshaft exhaust valve closing timing. The base camshaft inlet valve opening timing is 353.6 degree. The base camshaft exhaust valve closing timing is 363.6 degree.
[0023] The intake manifold 110 is used to facilitate uniform distribution of air to at least one cylinder (not shown) of the engine 10. In an embodiment, the intake manifold 110 includes at least one inlet runner 110a (as shown in fig. 4) and at least one outlet runner 100b (as shown in fig. 4). The inlet runner 110a of the intake manifold 110 is used to facilitate entry of filtered air from an air filter (not shown) to the intake manifold 110. The outlet runner 110b of the intake manifold 110 is used to facilitate exit of air from the intake manifold 110 to the cylinder (not shown) through cylinder head 108 of the engine 10.
[0024] The aforementioned engine 10 provides better combustion efficiency, high thermal efficiency, high volumetric efficiency, better engine power output, lower specific fuel consumption (SFC), increased knock resistance and reduced emission levels.
[0025] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

,CLAIMS:CLAIMS
We claim,
1. A combustion system 100 in an engine 10, said combustion system 100 comprising:
at least one piston 102;
at least one fuel injector 104;
at least one spark plug 106; and
at least one cylinder head 108 having at least one first cavity 108a adapted to receive said fuel injector 104 and at least one second cavity 108b adapted to receive said spark plug 106,
wherein
said fuel injector 104 adapted to be provided to the first cavity 108a of said cylinder head 108 at an angle from a longitudinal plane P of said cylinder head 108; and
said spark plug 106 adapted to be provided to the second cavity 108b of said cylinder head 108 at an angle from the longitudinal plane P of said cylinder head 108.
2. The combustion system 100 as claimed in claim 1, wherein said spark plug 106 is M12 spark plug.
3. The combustion system 100 as claimed in claim 1, wherein a bowl diameter of said piston 102 is in the range of 60 mm to 75 mm.

4. The combustion system 100 as claimed in claim 1, wherein a bowl angle of said piston 105 is in the range of 45 degree to 70 degree.
5. The combustion system 100 as claimed in claim 1, wherein the angle between said fuel injector 104 and the longitudinal plane P of said cylinder head 108 is in the range of 10 degree to 30 degree.
6. The combustion system 100 as claimed in claim 1, wherein the angle between said spark plug 106 and the longitudinal plane P of said cylinder head 108 is in the range of 0 degree to 20 degree.
7. The combustion system 100 as claimed in claim 1, wherein the engine 10 is at least one of a naturally aspirated compressed natural gas (CNG) direct injection engine, a turbocharged CNG direct injection engine and a naturally aspirated CNG engine.
8. The combustion system 100 as claimed in claim 7, wherein a compression ratio of the turbocharged CNG direct injection engine 10 is in the range of 12:1 to 15:1.
9. The combustion system 100 as claimed in claim 7, wherein a compression ratio of the naturally aspirated CNG direct injection engine 10 is in the range of 12:1 to 15:1.
10. The combustion system 100 as claimed in claim 7, wherein a bowl depth of said piston 102 is in the range of 12 mm to 18 mm for the naturally aspirated CNG direct injection engine 10.
11. The combustion system 100 as claimed in claim 7, wherein a bowl depth of said piston 102 is in the range of 13 mm to 17 mm for the turbocharged CNG direct injection engine 10.
12. The combustion system 100 as claimed in claim 1, wherein an angle between said fuel injector 104 and said spark plug 106 is in the range of 5 degree to 18 degree.
13. An engine 10 comprising:
at least one intake camshaft;
at least one exhaust camshaft;
at least one intake valve;
at least one exhaust valve; and
a combustion system 100 comprising at least one piston 102; at least one fuel injector 104; at least one spark plug 106; and at least one cylinder head 108 having at least one first cavity 108a adapted to receive said fuel injector 104 and at least one second cavity 108b adapted to receive said spark plug 106, wherein said fuel injector 104 adapted to be provided to the first cavity 108a of said cylinder head 108 at an angle from a longitudinal plane P of said cylinder head 108; and said spark plug 106 adapted to be provided to the second cavity 108b of said cylinder head 108 at an angle from the longitudinal plane P of said cylinder head 108,
wherein
said intake camshaft adapted to facilitate opening of said intake valve 10 degree before a base camshaft intake valve opening timing and said exhaust camshaft adapted to facilitate closing of said exhaust valve at a base camshaft exhaust valve closing timing.
14. The engine 10 as claimed in claim 13, wherein the base camshaft intake valve opening timing is 353.6 degree and the base camshaft exhaust valve closing timing is 363.6 degree.
15. An engine 10 comprising:
at least one intake camshaft;
at least one exhaust camshaft;
at least one intake valve;
at least one exhaust valve; and
a combustion system 100 comprising at least one piston 102; at least one fuel injector 104; at least one spark plug 106; and at least one cylinder head 108 having at least one first cavity 108a adapted to receive said fuel injector 104 and at least one second cavity 108b adapted to receive said spark plug 106, wherein said fuel injector 104 adapted to be provided to the first cavity 108a of said cylinder head 108 at an angle from a longitudinal plane P of said cylinder head 108; and said spark plug 106 adapted to be provided to the second cavity 108b of said cylinder head 108 at an angle from the longitudinal plane P of said cylinder head 108,
wherein
said intake camshaft adapted to facilitate opening said intake valve 10 degree before a base camshaft intake valve opening timing and said exhaust camshaft adapted to facilitate closing of said exhaust valve 10 degree after the base camshaft exhaust valve closing timing.
16. The engine 10 as claimed in claim 15, wherein the base camshaft intake valve opening timing is 353.6 degree and the base camshaft exhaust valve closing timing is 363.6 degree.
17. The engine 10 as claimed in claim 15, further comprising an intake manifold 110 adapted to facilitate uniform distribution of air to at least one cylinder of said engine 10.
18. The engine 10 as claimed in claim 15, wherein said engine 10 is at least one of a naturally aspirated compressed natural gas (CNG) direct injection engine, a turbocharged CNG direct injection engine and a naturally aspirated CNG engine.
19. The engine 10 as claimed in claim 15, wherein a hardness value of said intake valve seat is in the range of 60 HRA to 100 HRA.
20. The engine 10 as claimed in claim 15, wherein a hardness value of said exhaust valve seat is in the range of 60 HRA to HRA.