Description:FIELD OF THE INVENTION
[001] Present invention relates to a cylinder head assembly for an internal combustion engine. Embodiments of the disclosure also disclose the internal combustion engine including the cylinder head assembly.

BACKGROUND OF THE INVENTION
[002] Vehicles, are provided with a power unit such as an Internal Combustion (IC) engine. The IC engine is adapted to generate a motive force which propels the vehicle. The IC engine typically includes a cylinder head, a cylinder block mounted below the cylinder head and a crankcase that is mounted below the cylinder block. Additionally, the IC engine is also provided with one or more types of engine cooling mechanism, such as an air-cooling mechanism, an oil cooling mechanism and a liquid cooling mechanism. Based, on the type of cooling mechanism employed to the IC engine, overall efficiency and performance parameters of the IC engine are determined.
[003] Conventionally, IC engines of a smaller capacity, such as a 110cc, is provided with the air-cooling mechanism for cooling. The air-cooling mechanism is provided due to its simplicity in construction and for accommodating space constraints in the IC engine. Also, the air-cooling mechanism to the IC engine of smaller capacity is inexpensive and doesn’t require layout changes in the cylinder head. However, the IC engine provided with the air-cooling mechanism has poor efficiency. Also, an air entry passage in the air-cooling mechanism is subjected to entry of dust and pebbles during running condition of the vehicle, which is undesirable.
[004] Additionally, the IC engine is provided with an exhaust port, an exhaust channel extending from the exhaust port and an intake port. An oxygen sensor is also provided in the IC engine for sensing amount of oxygen present in exhaust gases that is discharged from the IC engine. However, the air-entry passage provided due to the air-cooling mechanism impinges onto the oxygen sensor, thereby reducing accuracy of sensing carbon emissions and amount of oxygen present in the exhaust gases.
[005] Furthermore, IC engine with the smaller capacity faces a problem that a higher power is required to initiate combustion of the fuel and air mixture, and thus for starting the vehicle. However, in IC engine provided with the air-cooling mechanism, under certain circumstances, when an electric start of the vehicle doesn’t work due to low battery, then a kick start mechanism is used to start the vehicle. In such circumstances, the rider is required to generate a high kick force for starting the vehicle. This high kick force in turn may induce trauma to leg and joints of the rider, which is undesirable.
[006] Thus, there is a need for a cylinder head for an IC engine, which addresses at least the aforementioned problems.

SUMMARY OF THE INVENTION
[007] In one aspect, a cylinder head assembly for an Internal Combustion (IC)
[008] engine is disclosed. The cylinder head assembly comprises an intake port provided on a cylinder head lower portion and is fluidically coupled to an intake opening. The intake port is adapted to route at least one of an air and a fuel into the IC engine. An exhaust port is provided in the cylinder head lower portion and is fluidically coupled to an exhaust opening. The exhaust port is adapted to discharge exhaust gases routed from the exhaust opening from the IC engine. An oil flow path is provided in the cylinder head lower portion. The oil flow path comprises one or more oil inlet ports and one or more oil outlet ports. Each of the one or more inlet ports and the one or more oil outlet ports are fluidically coupled to an oil sump of the IC engine. Each of the one or more oil inlet ports are adapted to route the oil from the oil sump to the oil flow path in the cylinder head lower portion. The oil flow path is adapted to circulate the oil within the cylinder head assembly for cooling.
[009] In an embodiment, the one or more oil inlet ports are provided on a right side of the cylinder head lower portion. The one or more inlet ports are located adjacently to a spark plug.
[010] In an embodiment, each of the one or more oil outlet ports is disposed on a left side of the cylinder head lower portion.
[011] In an embodiment, an oxygen sensor is provided to the exhaust port. The oxygen sensor comprises a probe portion disposed in the exhaust port, wherein the oxygen sensor is disposed at a predetermined orientation with respect to a vertical axis of the cylinder head assembly, wherein the predetermined orientation with respect to the vertical axis (Y-Y’) is between 10 degrees to 30 degrees.
[012] In an embodiment, the oxygen sensor is fastened in a hole provided in the cylinder head lower portion. The hole has screw threads for enabling fastening of the oxygen sensor.
[013] In an embodiment, a cylinder head top portion is provided on the cylinder head lower portion. The cylinder head top portion is provided with a decompression device. The decompression device is coupled to a camshaft of the IC engine and comprises a decompression valve. The decompression valve is operable to one of an open position and a closed position, wherein the decompression valve in the open position is adapted to vent pressure within a combustion chamber during a kick-start operation of the IC engine.
[014] In an embodiment, a spark plug is mounted to the cylinder head lower portion. The spark plug is displaced downwardly in the cylinder head lower portion corresponding to location of the decompression device, wherein the spark plug is disposed downwardly in the cylinder head lower portion upto a distance of 5mm along a vertical axis (Y-Y’) of the cylinder head assembly.
[015] In an embodiment, a recessed portion is provided in the cylinder head lower portion. The oil flow path is provided over the recessed portion.
[016] In another aspect, the IC engine for a vehicle is provided. The IC engine comprises a crankcase, a cylinder block mounted onto the crankcase and a cylinder head assembly mounted over the cylinder block. The cylinder head assembly comprises the intake port provided on the cylinder head lower portion and fluidically coupled to the intake opening. The intake port is adapted to route at least one of the air and the fuel into the IC engine. The exhaust port is provided in the cylinder head lower portion and is fluidically coupled to the exhaust opening. The exhaust port is adapted to discharge exhaust gases routed from the exhaust opening from the IC engine. The oil flow path is provided in the cylinder head lower portion. The oil flow path comprises the one or more oil inlet ports and one or more oil outlet ports. Each of the one or more inlet ports and the one or more oil outlet ports are fluidically coupled to the oil sump of the IC engine. Each of the one or more oil inlet ports are adapted to route the oil from the oil sump to the oil flow path in the cylinder head lower portion. The oil flow path is adapted to circulate the oil within the cylinder head assembly for cooling.

BRIEF DESCRIPTION OF THE DRAWINGS
[017] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figure 1 is a perspective view of a cylinder head assembly of an Internal Combustion (IC) engine, in accordance with an exemplary embodiment of the present invention.
Figure 2 is a front view of the cylinder head assembly, in accordance with an exemplary embodiment of the present invention.
Figure 3 is a sectional view of the cylinder head assembly along a plane A-A shown in Figure 2, in accordance with an exemplary embodiment of the present invention.
Figure 4 is a perspective view of the cylinder head assembly, in accordance with an exemplary embodiment of the present invention.
Figure 5 is a perspective view of the cylinder head assembly, in accordance with an exemplary embodiment of the present invention.
Figure 6 is a bottom view of the cylinder head assembly, in accordance with an exemplary embodiment of the present invention.
Figure 7 is a schematic view of the cylinder head assembly depicting an intake valve, an exhaust valve and a camshaft provided above a recessed portion, in accordance with an exemplary embodiment of the present invention.
Figure 8 is a schematic view of the cylinder head assembly depicting an intake valve, an exhaust valve and a camshaft provided above a recessed portion, in accordance with an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION
[018] The present invention relates to a cylinder head assembly for an Internal Combustion (IC) engine. The cylinder head assembly is provided with an oil flow path, for ensuring lubrication and cooling of components, thereby ensuring operation of the cylinder head assembly under optimal conditions. The IC engine is typically used in the vehicle such as a two-wheeled vehicle, a three-wheeled vehicle, a four wheeled vehicle or a multi-wheeled vehicle or any other application as per requirement. Additionally, the IC engine is a small capacity engine having a capacity of one of 100 cc or 125 cc.
[019] In the present disclosure, the arrow indications provided in Figures pertain to directional indications of the cylinder head assembly with respect to the vehicle. As such, the terms “front side”, “rear side”, “right side”, “left side”, “upside” and “downside” respectively correspond to front, rear, right, left, up and down sides of the cylinder head assembly with respect to the vehicle, until and unless specified otherwise.
[020] Figure 1 is a perspective view of a cylinder head assembly 100 of an Internal Combustion (IC) engine in accordance with an exemplary embodiment of the present invention. The cylinder head assembly 100 is mounted onto a cylinder block (not shown), wherein the cylinder block is mounted onto a crankcase (not shown). In the present embodiment, the IC engine is a small capacity engine. In the present embodiment, the IC engine is defined with a capacity of 100 cubic centimeters or 125cc cubic centimeters.
[021] The cylinder head assembly 100 further comprises a cylinder head top portion 128 and a cylinder head lower portion 112. The cylinder head lower portion 112 is provided below the cylinder head top portion 128. The cylinder head top portion 128 is adapted to enclose a camshaft 132 (as shown in Figures 4, 7 and 8), an intake valve assembly 138 (as shown in Figures 7 and 8) and an exhaust valve assembly 140 (as shown in Figures 7 and 8). The cylinder head assembly 100 is also provided with a cam chain window 122 (as shown in Figure 3). The cam chain window 122 is adapted to receive a continuous power transmission drive (not shown) such as a chain (not shown) or a belt (not shown) coupled to the camshaft 132 and a crankshaft in the crankcase.
[022] Referring to Figures 2 and 3 in conjunction with Figure 1, the cylinder head assembly 100 comprises an intake port 102 (as shown in Figure 3) provided on the cylinder head lower portion 112. The intake port 102 is fluidically coupled to an intake opening 104. The intake port 102 is adapted to route an air into the IC engine. The cylinder head assembly 100 also comprises an exhaust port 106 provided in the cylinder head lower portion 112. The exhaust port 106 is fluidically coupled to an exhaust opening 108. The exhaust port 106 is adapted to discharge exhaust gases routed from the exhaust opening 108 from the IC engine. The exhaust port 106 is provided at a front portion (not referenced in Figures) of the cylinder head lower portion 112, while the intake port 102 is provided at a rear portion (not referenced in Figures) of the cylinder head lower portion 112. As such, the intake port 102 is disposed oppositely to the exhaust port 106. In an embodiment, each of the intake port 102 and the exhaust port 106 is a channel that connects with the intake opening 104 and the exhaust opening 108, respectively.
[023] Further, an oxygen sensor 126 is disposed onto the exhaust port 106. The oxygen sensor 126 is adapted to determine amount of oxygen in the exhaust gases discharged from the IC engine upon combustion. Based on the amount of oxygen determined, an Electronic Control Unit (not shown) controls actuation of a fuel injection unit for tweaking or adjusting the quantity of fuel delivered to the IC engine, thereby improving fuel efficiency as well as performance in the IC engine. The oxygen sensor 126 comprises a probe portion 126a connected to a body portion 126b (as shown in Figure 1). The probe portion 126a is disposed in the exhaust port 106. Such a disposition of the oxygen sensor 126 in the exhaust port 106 ensures that the exhaust gases directly impinge onto the probe portion 126a of the oxygen sensor 126, thereby enhancing accuracy of detecting the amount of oxygen in the exhaust gases. Additionally, due to such disposition of the probe portion 126a within the exhaust port 106, the ambient air does not contact the probe portion 126a. Thus, the issues pertaining to deviation in detection of amount of oxygen in the exhaust gases due to influence of impingement of ambient air onto the oxygen sensor 126 is mitigated.
[024] In an embodiment, the exhaust port 106 is provided with a hole 146 (as shown in Figure 2) for receiving the oxygen sensor 126. Accordingly, dimensions of the hole 146 corresponds to dimensions of the oxygen sensor 126. The hole 146 is provided with screw threads for enabling engagement with the oxygen sensor 126. Thus, the oxygen sensor 126 is fastened onto the hole 146 provided on the exhaust port 106. The oxygen sensor 126 upon fastening onto the hole 146 is positioned such that, the body portion 126b is disposed outside of the exhaust port 106, while the probe portion 126a is disposed within the exhaust port 106.
[025] In an embodiment, the oxygen sensor 126 is disposed at a predetermined orientation α (as shown in Figure 2) with respect to a vertical axis Y-Y’ of the cylinder head assembly 100. Accordingly, the hole 146 is oriented at the predetermined orientation α for disposing the oxygen sensor 126 at the predetermined orientation α. The inclination is provided for ensuring accommodation of the oxygen sensor 126 onto the exhaust port 106. In an embodiment, the predetermined orientation α with respect to the vertical axis Y-Y’ is between 0 degrees and 30 degrees.
[026] In an embodiment, the cylinder head assembly 100 is provided with a plurality of slots 136 (as shown in Figure 5). The plurality of slots 136 align with through holes (not shown) provided on the cylinder block and on an upper wall (not shown) of the crankcase. A fastener (not shown) such as a bolt is inserted into each of the plurality of slots 136 and the through holes and fastened for connecting the cylinder block and the cylinder head assembly onto the crankcase.
[027] Referring to Figures 5 and 6 in conjunction with Figures 1-4, the cylinder head assembly 100 further comprises a recessed portion 110 provided on a bottom surface 120 of the cylinder head lower portion 112. The recessed portion 110 is provided at a central portion (not shown) of the cylinder head lower portion 112. The recessed portion 110 is provided with the intake opening 104 and the exhaust opening 108. Accordingly, the recessed portion 110 is adapted to receive an intake valve 142 (as shown in Figure 6) of the intake valve assembly 138 and an exhaust valve 144 (as shown in Figure 6) of the exhaust valve assembly 140. The intake valve 142 as well as the exhaust valve 144 are operable such that the intake opening 104 and the exhaust opening 108 are selectively opened. The recessed portion acts as a top portion of a combustion chamber (not shown) provided in the cylinder block. Accordingly, the air and/or the fuel selectively enters into the recessed portion 110, and the exhaust gases generated post combustion of the air and/or the fuel is selectively discharged from the recessed portion 110.
[028] Referring to Figures 7 and 8 in conjunction with Figure 1-6, the cylinder head assembly 100 is provided with an oil flow path 114 that is fluidly coupled to an oil sump (not shown). The oil flow path 114 is adapted to enable flow of lubricating oil from the oil sump into the cylinder head assembly 100, and thus ensure cooling. Such a construction of the oil flow path 114 enables cooling of the cylinder head assembly 100, even for the cylinder head assembly 100 of the IC engine defined with a smaller capacity.
[029] The oil flow path 114 is provided in the cylinder head lower portion 112 and is disposed above the recessed portion 110. In an embodiment, the oil flow path 114 is disposed over a top surface 110a of the recessed portion 110. The oil flow path 114 comprises one or more oil inlet ports 116 and one or more oil outlet ports 118. The one or more inlet ports 116 and the one or more oil outlet ports 118 are fluidically coupled to the oil sump. Each of the one or more oil inlet ports 116 is adapted to route the oil from the oil sump to the oil flow path 114 in the cylinder head lower portion 112. Each of the one or more oil outlet ports 118 is adapted to discharge the oil from the cylinder head lower portion 112 to the oil sump. In an embodiment, the oil sump is provided within the crankcase.
[030] In an embodiment, each of the one or more oil inlet ports 116 is provided on a right side 112a (as shown in Figure 6) of the cylinder head lower portion 112. In an embodiment, each of the one or more inlet ports 116 is located adjacently to the spark plug 124. In an embodiment, each of the one or more oil outlet ports 118 is disposed on a left side 112b (as shown in Figure 6) of the cylinder head lower portion 112. In an embodiment, location of each of the one or more inlet ports 116 as well as each of the one or more outlet ports 118 on the recessed portion is selected as per design feasibility and requirement in the oil flow path 114 and/or the cylinder head assembly 100.
[031] In an embodiment, the oil from the oil sump is routed into each of the inlet ports 116 through one of a splashing method or a pump method. In an embodiment, the splashing method is achieved through splashing of the oil into each of the one or more inlet ports 116 by the continuous power transmission drive connecting the crankshaft and the camshaft 132. In an embodiment, each of the one or more inlet ports 116 are coupled to a pump device (not shown) such as an oil pump. The pump device is adapted to pump the oil from the oil sump to each of the one or more inlet ports 116.
[032] Further, a decompression device 130 (shown in Figure 7) is provided in the cylinder head assembly 100. As such, even the IC engine with the smaller capacity is provided with the decompression device 130. The decompression device 130 is disposed near the spark plug 124 and coupled to the camshaft 132 of the IC engine and comprises a decompression valve 134. The decompression valve 134 is operable to one of an open position (not shown) and a closed position (not shown). The decompression valve 134 in the open position is adapted to vent pressure within the combustion chamber (not shown) during a kick-start operation of the IC engine, thereby reducing trauma induced to a rider of the vehicle during the kick-start operation. In an embodiment, the decompression device 130 is disposed diametrically opposite to the camshaft 132.
[033] Further, the spark plug 124 is mounted to the cylinder head lower portion 112. The spark plug 124 is displaced downwardly in the cylinder head lower portion 112 corresponding to location of the decompression device 130. Such a disposition of the spark plug 124 is considered for accommodating the decompression device 130 in the cylinder head assembly 100. The spark plug 124 is disposed downwardly in the cylinder head lower portion 112 upto a distance of 5mm along a vertical axis Y-Y’ of the cylinder head assembly 100. Accordingly, the orientation of the spark plug 124 varies corresponding to the size of the decompression device 130.
[034] The claimed invention as disclosed above is not routine, conventional or well understood in the art, as the claimed aspects enable the following solutions to the existing problems in conventional technologies. Specifically, the claimed aspect of providing the oil flow path in the cylinder head assembly ensures that cylinder head assembly is cooled. Thus, the components in the cylinder head assembly operate in optimal operating conditions, thereby enhancing performance and durability of the components. Additionally, the cylinder head assembly of the present invention is provided for IC engine with smaller capacity of 100cc or 125cc. Thus, the construction of the oil flow path in the cylinder head assembly is made possible in smaller capacity IC engines as well.
[035] Further, the probe portion is disposed in the exhaust port. Such a disposition of the oxygen sensor in the exhaust port ensures that the exhaust gases directly impinge onto the probe portion of the oxygen sensor, thereby enhancing accuracy of detecting the amount of oxygen in the exhaust gases. Additionally, due to such disposition of the probe portion within the exhaust port, the ambient air does not contact the probe portion. Thus, the issues pertaining to deviation in detection of amount of oxygen in the exhaust gases due to influence of impingement of ambient air onto the oxygen sensor is mitigated.
[036] Moreover, the cylinder head assembly is provided with the decompression device for relieving trauma induced to the rider during kick-starting operation of the IC engine for starting.
[037] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.

List of Reference Numerals
100 – Cylinder head assembly
102 – Intake port
104 – Intake opening
106 – Exhaust port
108 – Exhaust opening
110 – Recessed portion
112 – Cylinder head lower portion
112a – Right side of the cylinder head lower portion
112b – Left side of the cylinder head lower portion
114 – Oil flow path
116 – One or more oil inlet ports
118 – One or more oil outlet ports
120 – Bottom surface of the cylinder head lower portion
122 – Cam chain window
124 – Spark plug
126 – Oxygen sensor
126a – Probe portion of Oxygen sensor
126b – Body portion of Oxygen sensor
128 – Cylinder head top portion
130 – Decompression device
132 – Camshaft
134 – Decompression valve
136 – Plurality of slots
138 – Intake valve assembly
140 – Exhaust valve assembly
142 – Intake valve
144 – Exhaust valve
146 – Hole on exhaust port
, Claims:1. A cylinder head assembly (100) for an Internal Combustion (IC) engine, the cylinder head assembly (100) comprising:
an intake port (102) provided on a cylinder head lower portion (112) and fluidically coupled to an intake opening (104), the intake port (102) being adapted to route air into the IC engine;
an exhaust port (106) provided in the cylinder head lower portion (112) and fluidically coupled to an exhaust opening (108), the exhaust port (106) being adapted to discharge exhaust gases routed from the exhaust opening (108) from the IC engine;
an oil flow path (114) provided in the cylinder head lower portion (112), the oil flow path (114) comprising one or more oil inlet ports (116) and one or more oil outlet ports (118), each of the one or more inlet ports (116) and the one or more oil outlet ports (118) being fluidically coupled to an oil sump of the IC engine,
wherein each of the one or more oil inlet ports (116) being adapted to route the oil from the oil sump to the oil flow path (114) in the cylinder head lower portion (112), the oil flow path (114) being adapted to circulate the oil within the cylinder head assembly (100) for cooling of the IC engine.

2. The cylinder head assembly (100) as claimed in claim 1, wherein the one or more oil inlet ports (116) being provided on a right side (112a) of the cylinder head lower portion (112), the one or more inlet ports (116) being located adjacently to a spark plug (124).

3. The cylinder head assembly (100) as claimed in claim 1, wherein each of the one or more oil outlet ports (118) being disposed on a left side (112b) of the cylinder head lower portion (112).

4. The cylinder head assembly (100) as claimed in claim 1, wherein an oxygen sensor (126) being provided to the exhaust port (106), the oxygen sensor (126) comprising a probe portion (126a) being disposed in the exhaust port (106), wherein the oxygen sensor (126) being disposed at a predetermined orientation (α) with respect to a vertical axis (Y-Y’) of the cylinder head assembly (100),
wherein the predetermined orientation (α) with respect to the vertical axis (Y-Y’) is between 0 degrees and 30 degrees.

5. The cylinder head assembly (100) as claimed in claim 4, wherein the oxygen sensor (126) being fastened in a hole (146) provided in the cylinder head lower portion (112), the hole (146) having screw threads for enabling fastening of the oxygen sensor (126).

6. The cylinder head assembly (100) as claimed in claim 1 comprises a cylinder head top portion (128) provided on the cylinder head lower portion (112), the cylinder head top portion (128) being provided with a decompression device (130), the decompression device (130) disposed proximally to a spark plug (124) and being coupled to a camshaft (132) of the IC engine and comprises a decompression valve (134), the decompression valve (134) being operable to one of an open position and a closed position,
wherein the decompression valve (134) in the open position is adapted to vent pressure within a combustion chamber during a kick-start operation of the IC engine.

7. The cylinder head assembly (100) as claimed in claim 6 comprising a spark plug (124) mounted to the cylinder head lower portion (112), the spark plug (124) being displaced downwardly in the cylinder head lower portion (112) corresponding to location of the decompression device (130),
wherein the spark plug (124) being disposed downwardly in the cylinder head lower portion (112) upto a distance of 5mm along a vertical axis (Y-Y’) of the cylinder head assembly (100).

8. The cylinder head assembly (100) as claimed in claim 1, comprising a recessed portion (110) provided in the cylinder head lower portion (112), the oil flow path (114) being provided over the recessed portion (110).

9. An Internal Combustion (IC) engine for a vehicle, the IC engine comprising:
a crankcase;
a cylinder block mounted onto the crankcase; and
a cylinder head assembly (100) mounted over the cylinder block, the cylinder head assembly (100) comprising:
an intake port (102) provided on a cylinder head lower portion (112) and fluidically coupled to an intake opening (104), the intake port (102) being adapted to route air into the IC engine;
an exhaust port (106) provided in the cylinder head lower portion (112) and fluidically coupled to an exhaust opening (108), the exhaust port (106) being adapted to discharge exhaust gases routed from the exhaust opening (108) from the IC engine;
an oil flow path (114) provided in the cylinder head lower portion (112), the oil flow path (114) comprising one or more oil inlet ports (116) and one or more oil outlet ports (118), each of the one or more inlet ports (116) and the one or more oil outlet ports (118) being fluidically coupled to an oil sump of the IC engine,
wherein each of the one or more oil inlet ports (116) being adapted to route the oil from the oil sump to the oil flow path (114) in the cylinder head lower portion (112), the oil flow path (114) being adapted to circulate the oil within the cylinder head assembly (100) for cooling.

10. The IC engine as claimed in claim 9, wherein the one or more oil inlet ports (116) being provided on a right side (112a) of the cylinder head lower portion (112), the one or more inlet ports (116) being located adjacently to a spark plug (124).

11. The IC engine as claimed in claim 9, wherein each of the one or more oil outlet ports (118) being disposed on a left side (112b) of the cylinder head lower portion (112).

12. The IC engine as claimed in claim 9, wherein an oxygen sensor (126) being provided to the exhaust port (106), the oxygen sensor (126) comprising a probe portion (126a) being disposed in the exhaust port (106), wherein the oxygen sensor (126) being disposed at a predetermined orientation (α) with respect to a vertical axis (Y-Y’) of the cylinder head assembly (100),
wherein the predetermined orientation (α) with respect to the vertical axis (Y-Y’) is between 0 degrees and 30 degrees.

13. The IC engine as claimed in claim 12, wherein the oxygen sensor (126) being fastened in a hole (146) provided in the cylinder head lower portion (112), the hole (146) having screw threads for enabling fastening of the oxygen sensor (126).

14. The IC engine as claimed in claim 9 comprises a cylinder head top portion (128) provided on the cylinder head lower portion (112), the cylinder head top portion (128) being provided with a decompression device (130), the decompression device (130) being coupled to a camshaft (132) of the IC engine and comprises a decompression valve (134), the decompression valve (134) being operable to one of an open position and a closed position,
wherein the decompression valve (134) in the open position is adapted to vent pressure within a combustion chamber during a kick-start operation of the IC engine.

15. The IC engine as claimed in claim 14 comprising a spark plug (124) mounted to the cylinder head lower portion (112), the spark plug (124) being displaced downwardly in the cylinder head lower portion (112) corresponding to location of the decompression device (130),
wherein the spark plug (124) being disposed downwardly in the cylinder head lower portion (112) upto a distance of 5mm along a vertical axis (Y-Y’) of the cylinder head assembly (100).

16. The IC engine as claimed in claim 9 comprising a recessed portion (110) provided in the cylinder head lower portion (112), the oil flow path (114) being provided over the recessed portion (110).