TECHNICAL FIELD
[0001] The present subject matter relates generally to an engine assembly for a two or three-wheeled vehicle, and more particularly but not exclusively to an exhaust emission system for the engine assembly.
BACKGROUND
[0002] Generally, a vehicle comprises of a frame assembly extending rearwardly from a head tube. The frame assembly acts as a skeleton and a structural member for the vehicle that supports the vehicle loads. At least one front wheel is connected to a front portion of the frame assembly through one or more front suspension(s). The frame assembly extends towards a rear portion of the vehicle. At least one rear wheel is connected to a frame assembly through one or more rear suspension(s). The frame assembly comprises of an engine assembly coupled to it. The"engine assembly is functionally connected to the rear wheel, which provides forward motion to the vehicle. A muffler assembly is provided at a lateral side of the vehicle mounted to the frame assembly or the vehicle through a mounting bracket. The muffler assembly extends in a rearward direction along the length of the vehicle. An exhaust port is provided in the engine assembly through which an exhaust pipe extends in a reverse direction forming a part of the muffler assembly. [0003] These vehicles incorporating the internal combustion engine are powered by gasoline or diesel. Combustion process that takes place in the internal combustion engine is converted into mechanical energy for producing the required amount of power and torque. Also, the combustion process generates exhaust gas that is to be scavenged into the atmosphere. An exhaust system is very essential system of the vehicle as the exhaust gasses are to be carefully treated before emitting into the atmosphere. AJso, the exhaust system is essential to determine the effective working of the engine. Conventionally, in a vehicle the muffler assembly is provided to dampen the noise arising from the engine. The muffler assembly also comprises of a catalytic converter which helps in oxidation of the NOX into harmless oxides which are ultimately released in the atmosphere.

BRIEF DESCRIPTION OF THE DRAWINGS
[0004] The detailed description of the present subject matter is described with
reference to the accompanying figures. Same numbers are used throughout the
drawings to reference like features and components.
[0005] Fig. 1 illustrates a left side view of an exemplary two-wheeled vehicle, in
accordance with an embodiment of the present subject matter.
[0006] Fig. 2 depicts a left side view of the engine assembly 100, in accordance
with theembodiment.
[0007] Fig. 3 illustrates a top view of a cylinder head of the engine assembly.
[0008] Fig. 4 is a sectional view of the cylinder head assembly taken along A-A
axis as shown in the Fig. 3.
[0009] Fig. 5 illustrates a sectional view of the cylinder head assembly including
at least one detecting member; the section is taken along A-A axis as shown in
the Fig. 3.
[00010] Fig. 6 is a sectional view of the cylinder head assembly taken along A-A
axis as shown in the Fig. 3.
[00011] Fig. 7 illustrates a top perspective view of the cylinder head assembly.
[00012] Fig. 8 illustrates a top view of a cylinder head cover.
[00013] Fig.9 illustrates the depression configured in the cylinder block of the
engine assembly.
DETAILED DESCRIPTION [00014] Typically, in a two-wheeled vehicle, the engine assembly is mounted to the body frame or is swingably connected to the frame assembly. The engine assembly is provided with an' air supply system and a fuel supply system that supply air-fuel mixture from an air filter and a fuel tank respectively. Combustion of air-fuel mixture takes place in a cylinder portion of the engine assembly. The combustion process either in two-stroke or four-stroke engine creates reciprocating motion of a piston disposed therein. The reciprocating motion of the piston is converted into rotary motion of the crankshaft thereby generating desired power/torque that gets transmitted to at least one wheel of the vehicle.

[00015] Typically, a two-wheeled vehicle is operated through an engine assembly which is horizontally coupled to the rear end of the frame assembly and a fuel tank disposed between the rear portions of the pair of the side tubes. Air fuel mixture is supplied to the engine assembly by means of a carburetor. Thereafter combustion of the air fuel mixture takes place so that a piston disposed in the engine assembly is set into motion. The piston is operated in a linear motion, after which said liner motion is converted to a rotational motion, wherein said rotational motion is transferred to the rear wheel finally resulting into motion of the vehicle. This mechanism also results in generation of power and torque by the engine assembly. [00016] Generally, an exhaust system of a two wheeled vehicle extends in a downward manner from the engine assembly and further extending rearwardly along the length of the vehicle. The un-bumt air-fuel mixture in form of exhaust gases is emitted in the atmosphere after a proper oxidation reaction which takes place in the muffler assembly. Typically, the exhaust gases enter the exhaust system through a main exhaust pipe and later pass through the adapter to the catalytic converter for conversion.
[00017] Also, the air-fuel mixture defines the fuel consumption and performance of the engine. Generally, a closed loop control is used to control air-fuel mixture thereby providing fuel economy and providing reduced emissions. For example, a lambda sensor is mounted to the engine assembly to quantify the oxygen concentration or concentration of other gases depending on which a control system modifies the fuel quantity. r
[00018] It is known in the art, wherein the lambda sensor is mounted in the exhaust pipe of the engine assembly. The exhaust pipe is a connection between the exhaust port and the muffler. The lambda_ sensor placed in the exhaust pipe is considerably away from the exhaust port. The temperature of the exhaust gases is the highest at the exhaust port. However, the temperature reduces as the exhaust gases traverse away from the exhaust port through the exhaust pipe. Under such circumstances, the lambda sensor may not provide appropriate results by sensing the available exhaust gases in the exhaust pipe. Therefore, in order to'bbtain more

accurate results from the lambda sensor, it is desirable to dispose the lambda sensor closer to the exhaust port.
[00019] Accordingly, the lambda sensor used to measure the oxygen concentration of exhaust gas in the engine assembly is preferably placed at nearest point where the exhaust temperature is high enough to measure the oxygen concentration in exhaust gasses exiting from the cylinder head exhaust port. Typically, the cylinder head of the engine assembly is an integral cylinder head type including a cylinder head cover as an integral part and a split cylinder head type including a separate cylinder head cover. In a split cylinder head type engine, numerous dynamic parts including the valves, the valve train parts are to . be assembled during multiple assembly operations due to presence of multiple split parts. Here, the time taken to assemble the dynamic parts is more and also the split cylinder head type engine has more number of parts. The cost of the split cylinder head type engine is also increased due to more number of parts. Whereas, in the integrated cylinder head type engine, all the dynamic parts are already assembled inside the cylinder head that is covered by a simple cylinder head cover. Just by accessing the cylinder head cover, the dynamic parts inside the cylinder head can be easily accessed for servicing and replacement. Further, the number of split parts is also reduced in the integrated cylinder head type engine.
[00020] The lambda sensor in both the integral cylinder head type and the split cylinder head type can be disposed outside a fin area in the cylinder head by providing a suitable boss to accommodate the lambda sensor. However, in the case of a split cylinder head type engine assembly, the fins extend till the end of the exhaust port. Therefore, in the split cylinder head type engine assembly, it is challenging and tedious to accommodate the lambda sensor. It is known in the art, wherein in a split cylinder head type of engine assembly, the lambda-sensor is accommodated by providing a suitable boss projected beyond the exhaust port. However, such a projected boss is not desirable, because, the lambda sensor will also correspondingly project out of the projected boss and away from the exhaust port. This may result in damage to the lambda sensor due to interference with

surrounding' parts. Further, it becomes a challenging task with complex engineering required to accommodate the lambda sensor in the split cylinder head type of engine assembly. Therefore, there is a need for a simpler mounting design to accommodate the lambda sensor in the cylinder head.
[00021] However, there are various challenges in disposing the lambda sensor at a proximity to the exhaust port. The lambda sensor closer to the exhaust port is always associated with packaging issues due to interference with layout design, sub-system level interface issues and also the lambda sensor disposed in the cylinder head adds to the weight of the cylinder head.
[00022] The at least one detecting member in known art, when disposed away from the exhaust port is often subject to high concentration of contamination in the exhaust gases due to more accumulation of the exhaust gases and also until the exhaust gases reaches the at least one detecting member disposed away from the exhaust port. Under such circumstances, the catalytic action performed on the exhaust gases increases and which may result in quicker deterioration of the catalyst, which further, calls for frequent servicing for replacement of the catalytic converter. The exhaust gases after passing out of the locus point, enter into the exhaust pipe and expand there within, which may lead to inappropriate detecting of the oxygen concentration by the at least one detecting member. [00023] Therefore, it is always desirable to have the at least one detecting member disposed closer to the exhaust port, which is more efficient and provides better performance.
[00024] According to an embodiment of the present invention, a two-wheeled vehicle includes an engine assembly comprising a cylinder, a cylinder head attached to the cylinder. Further, a cylinder head cover is disposed upon the cylinder head to cover at least a portion of the cylinder head. The cylinder head of the engine assembly includes one or more ports. The one or more ports include at least one input port and at least one exhaust port for intake and exhaust of the air-fuel mixture and the exhaust gases respectively.
[00025] According to an embodiment of the present invention, at least one detecting member for detecting the oxygen concentration in the exhaust gases

emitted from the exhaust port is disposed in the exhaust port. The at least one detecting member will accordingly detect the oxygen concentration in the exhaust gases inside the exhaust port and send the signals to a controller configured to provide input signals for appropriate action of a catalyst. The at least one detecting member is, for example, a lambda sensor also called as an oxygen sensor.
[00026] According to an embodiment of the present invention, the at least one detecting member is disposed in the exhaust port. The exhaust port includes an originating portion, from which the exhaust gases from the combustion chamber originate to traverse through the exhaust port. The exhaust port further includes an emerging portion, through which the exhaust gases are emerging outside of the exhaust port to travel into an exhaust pipe connecting between the exhaust port and a muffler. Further, the exhaust port includes an exhaust path traversing between the originating portion and the emerging portion, the exhaust path is for traversing of the exhaust gases in the exhaust port.
[00027] The exhaust port is adjoined by an exhaust pipe to pass on the exhaust gases to the muffler. The exhaust port and .the exhaust pipe together are so designed to form a curved structure including an increasing curve in the exhaust port and a decreasing curve in the exhaust pipe. The increasing curve and the decreasing curve form a locus point disposed at a junction between the exhaust port and the exhaust pipe. In other words, the locus point so formed is sandwiched at the mating surface such that it is between the exhaust port and the exhaust pipe. The curved structure is elevated at the locus point. The locus point in the exhaust port is where the exhaust gases are accumulated inside the exhaust port having a greater cross-section, wherein abundant exhaust gases are available for the at least one detecting member for sensing the oxygen concentration appropriately. The availability of greater surface area at the locus point inside the exhaust port results in accurate functioning of the at least one detecting member, which further results in accurate functionality of the catalytic converter. This way, the catalytic converter need not be replaced frequently, which further does not call for frequent servicing of the exhaust system of the engine assembly.

Further, therefore, a more reliable functioning of the at least one detecting
member is achieved according to the proposed invention.
[00028] Therefore, according to an embodiment of the present invention, the at
i
least one detecting member is disposed ahead of the locus point in the curved structure. Such that, abundance of the exhaust gases are readily available for detecting of the oxygen concentration by the at least one detecting member. [00029] According to an embodiment of the present invention, the exhaust path inside the exhaust port is connected with a continuous exhaust path inside the exhaust pipe to let the exhaust gases outside into the atmosphere through the muffler.
[00030] According to an embodiment of the present invention, at least a portion of the cylinder head, forming the exhaust path includes a depression configured to receive at least a portion of the at least one detecting member. In particular, the at least one detecting member includes a detecting portion disposed inside the depression.
[00031] According to another embodiment of the present invention, the depression includes a threaded hole configured to receive the detecting portion of the at least one detecting member. Further, the cylinder head covered by the cylinder head cover also includes a contour comprising . a 'C* shape in conformation and in-line with the depression. Such that, the cylinder head portion and the cylinder head cover portion at a proximity to the at least one detecting member do not interfere with the at least one detecting member. Further, the threaded hole provides a stable mounting of the at least one detecting member inside the exhaust port in the cylinder head. This ensures that minimum vibrations and other impacts are transferred to the at least one detecting member during the engine assembly operation.
[00032] According to an embodiment of the present invention, the exhaust port, and the exhaust pipe forming the curved structure is disposed below a horizontal component passing through the locus point in the exhaust port. The curved structure is disposed with respect to the detecting portion such that the horizontal

component passing through the locus point and the detecting portion is always a tangent to the curved structure.
[00033] According to an embodiment of the present invention, the at least one detecting member is disposed in any of the orientation with respect to the ■horizontal component. Any of the orientations of the detecting member with respect to the horizontal component includes a vertical direction, a horizontal direction, and at an angle in the range of 0 degrees to 90 degrees.
[00034] Fig. 1 illustrates a left side view of an exemplary two-wheeled vehicle 200, in accordance with an embodiment of the present subject matter. Arrows provided in the top right comer of each figure depicts direction with respect to the vehicle, wherein an arrow F denotes front direction, an arrow R indicates rear direction, an arrow Up denotes upward direction, and an arrow Dw denotes downward direction. The vehicle 200 includes a frame assembly 201 that extends rearward from a head tube 201A. The frame assembly 201 extends along in a longitudinal direction F-R of the vehicle 200. The frame assembly 201 includes a mainframe comprising a main tube 201B extending rearward from a rear portion of the head rube 201A and a down tube 201C that extends rearwardly downward from the head tube 201 A. The frame assembly 201 may further comprise a sub-frame formed by a pair of rear tubes that extend obliquely rearward from the main frame. An engine assembly 100 is mounted to the main frame of the frame assembly 201.
[00035] The engine assembly 100 acts as the power unit of the vehicle 200, wherein the power unit may also include a traction/electrical motor (not shown). The engine assembly 100 is coupled to an exhaust assembly 110 that scavenges exhaust gases there through. A front portion of a swing arm 115 is swingably connected to the frame assembly 201 and a rear portion of the swing arm 115 rotatably supports a rear wheel 120. The rear wheel 120 is functionally coupled to the engine assembly 100 through a transmission system/member 125. In a preferred embodiment, the transmission system 125 includes a chain drive coupled to an output of manual gear transmission. However, the transmission

system 125 may include an automatic transmission or continuously variable transmission. Further, the swing arm 115 is coupled to the frame assembly 201 through one or more rear suspension(s) (not shown). In the present embodiment, a mono-shock rear suspension connects the swing arm 115 to the frame assembly 201. Similarly, a pair of front forks 130 supports a front wheel 135 and is steerably supported by the head tube 201 A. A handlebar assembly 140 is connected to an upper portion of the pair of front forks 130. Further, a front fender 145 covers at least a portion of the front wheel 135 and the front fender assembly 145 is mounted to the front forks 130.
[00036] A fuel tank 150 is mounted to the main tube 201B of the frame assembly 201 and disposed rearwardly of the handlebar assembly 140. A seat assembly including a rider seat 155 and a pillion seat 160 is disposed rearwardly of the fuel tank assembly 150 and is supported by the rear tubes. A pair of rider foot pegs 165 is disposed on either sides and is mounted to the frame assembly 201 of the vehicle that supports rider foot. A rear fender 170 is disposed upwardly of the rear wheel 120 covering at least a portion of the rear wheel 120.
[00037] Further, the engine assembly 100 is functionally coupled to an air-fuel supply system (not shown) that supplies air and fuel to the engine assembly 100. The torque/power output of the engine assembly 100 is transferred to a drive sprocket (not shown). A chain drive 125 is coupled to the drive sprocket. A sprocket cover encloses the drive sprocket and at least a portion of the chain drive 125.
[00038] Furthermore, the vehicle 200 includes various electrical and electronic systems including a starter motor (not shown), a headlamp 175, a vehicle control unit, and a tail lamp 180. In addition, the vehicle includes safety systems including a synchronous braking system (not shown), and an anti-lock braking system.
[00039] Fig. 2 depicts a left side view of the engine assembly 100, in accordance with the embodiment. In the present embodiment, the engine assembly 100 includes at least one cylinder head 102 comprising at least one intake valve (not
■ i. J • ■!— — -

shown) and at least one exhaust valve (not shown). The cylinder head 102 is mounted to a cylinder block 101. The cylinder block 101 defines a cylinder portion and a piston (not shown) is radially enclosed by the cylinder portion. The cylinder head 102 is covered by a cylinder head cover 109 from a top direction. The cylinder block 101 is mounted to a crankcase 202. In the present embodiment, the engine assembly 100 is forwardly inclined type. The inclination is of a piston axis defined by reciprocating motion of the piston. In another embodiment, a vertical or a horizontal engine may be used.
[00040] The cylinder head 102 includes one or more ports. The one or more ports include at least one intake port 106 and at least one exhaust port 103.
[00041] The crankcase 202 rotatably supports plurality of engine components including the crankshaft. The reciprocating motion of the piston is converted into the rotary motion of the crankshaft. Further, the engine assembly 100 includes a clutch assembly (not shown) mounted on one latera^ side of the engine assembly and a magneto or an integrated starter generator (not shown) is mounted to another side of the engine assembly 100. The clutch assembly is enclosed by a clutch cover (not shown) that is mounted to the crankcase 202. Similarly, the magneto is enclosed by a magneto cover 203 that is mounted to the crankcase 202. In the present embodiment, the clutch cover is disposed on the right hand side RH of the engine assembly and the magneto cover 203 is disposed on the left hand side LH of the engine assembly 100. A gear actuation drum (not shown) is coupled to a gear arm that is coupled to a gearshift lever for shifting gears. In addition, a sensor is mounted to the crankcase body for identifying the gear position. In one embodiment, the sensor is mounted to identify the crankshaft speed.
[00042] Fig. 3 illustrates a top view of a cylinder head of the engine assembly. The cylinder head 106 comprises the at least one exhaust port 103. At least a portion of the cylinder head 106 is configured to form the exhaust port 103. The at least a portion of the cylinder head 106 on a top surface 103Ts of the exhaust port 103 is configured to form a depression 301.

[00043] Fig. 4 is a sectional view of the cylinder head assembly taken along A-A axis as shown in the Fig. 3. The exhaust port 103 includes an originating portion 1 103a, from which the exhaust gases originate after undergoing combustion in the combustion chamber in the cylinder block 101. Further, after originating from the originating portion 103a, the exhaust gases traverse through the exhaust path 103ca inside the exhaust port 103. The exhaust port 103 ends at an emerging portion 103b, from which the exhaust gases emerge out of the exhaust port 103 and enter the exhaust pipe 104. The exhaust pipe' 104 includes a continuous exhaust path 103cb there within, through which the exhaust gases are passed on to a muffler (not shown) to let the exhaust gases out into the atmosphere. The cylinder head 106 includes a depression 301 extending through the exhaust port 103.
[00044] Fig. 5 illustrates a sectional view of the cylinder head assembly including at least one detecting member, the section is taken along A-A axis as shown in the Fig. 3. The exhaust port 103 includes at least one detecting member 105 to detect one or more gaseous components in the exhaust gas traversing along the exhaust path 103ca from the originating portion 103a to the emerging portion 103b. The exhaust port 103 is adjoined by the exhaust pipe 104. The exhaust port 103 and the adjoining exhaust pipe 104 include an outer circumferential surface 108a, 108b to form a curved structure. The outer circumferential surface 108a, 108b includes an increasing curve 108a, which is an outer circumferential surface of the exhaust port 103, and a decreasing curve 108b, which is an outer circumferential surface of the intake port 106. The increasing curve 108a and the decreasing curve 108b includes a locus point 107 sandwiched at the mating interface between the exhaust port 103 and the exhaust pipe 104. The increasing curve 108a is elevated at the locus point 107. At the locus point 107, the cross section of the exhaust port 103 is the highest, the exhaust gases accumulated are considerably abundant at this cross-section and the at least one detecting member 105 disposed at the locus point 107 is readily available to detect the exhaust gases.

[00045] According to an embodiment of the present invention, the at least one detecting member 105 includes a detecting portion 105a disposed upstream of and at a close proximity to the locus point 107 in the exhaust port 103. Such that, the at least one detecting member 105 can readily detect the one or more required gaseous components from the abundantly available exhaust gases around the locus point 107. This results in an accurate working of the at least one detecting member 105, which further results in efficient usage of the catalytic converter.
[00046] Fig. 6 is a sectional view of the cylinder head assembly taken along A-A axis as shown in the Fig. 3. According to an embodiment of the present invention, the detecting portion 105a of the at least one detecting member 105 and the locus point 107 are disposed to be in-line along the exhaust port. Further, a horizontal component HZ passing through the detecting portion 105a and the locus point 107 are disposed with respect to the outer circumferential surface 108a, 108b such that the horizontal component HZ is always a tangent to the outer circumferential surface 108a, 108b. Further, the outer circumferential surface 108a, 108b including the at least one detecting portion 105a is always disposed below the horizontal component HZ, such that a top most portion 105Tp . of the at least one detecting member 105 is always disposed below an axis PP" passing through the cylinder head cover 109. The axis PP" is the highest point in the cylinder head. This ensures that the at least one detecting member 105 does not interfere with other surrounding parts of the engine assembly 100 and other surrounding vehicular parts. In addition, furthermore, at least a portion of the at least one detecting member 105 is surrounded by the cylinder head 102, thereby protecting the at least a portion of the at least one detecting member 105. To achieve the same, the at least one detecting member 105 is disposed at an offset to the axis PP" when viewed from a top view.
[00047] Furthermore, the at least one detecting member 105 includes a central axis 105b passing centrally longitudinally through the at least one detecting member 105, the orientations of the central axis 105b of the at least one detecting member 105 with respect to the horizontal component HZ includes a vertical

direction, a horizontal direction, and at an angle in the range of 0 degrees to 90 degrees.
[00048] Fig. 7 illustrates a top perspective view of the cylinder head assembly. According to an embodiment of the present invention, the at least a portion of the cylinder head 109 includes the depression 301 configured to receive the detecting portion 105a (not shown) of the at least one detecting member 105. The depression 301 includes a shape in conformation and in-line with at least a portion of the at least one detecting" member 105. Further, the cylinder head cover 109 includes a 'C shaped contour 302, which has a shape to be in conformation and in-line to the portion of the at least one detecting member 105 disposed at a proximity to the cylinder head cover 109 as shown in the Fig. 8. The depression 301 and the 'C shaped contour 302 are configured to protect the at least one detecting member 105 from interfering with the cylinder block 102 and the cylinder head cover 109.
[00049] Fig.9 illustrates the depression configured in the cylinder block of the engine assembly. The depression 301 in the exhaust port 103 includes a hole 301H to receive the detecting portion of the at least one detecting member (not shown). Further, the hole 301H includes plurality of serrations 301th to securely receive the detecting portion of the at least one detecting member. The hole 301H is a through hole to allow the at least one detecting member to extend substantially inside the exhaust port 103 and be able to accurately detect the one or more gaseous components in the exhaust gases.
[00050] According to an embodiment of the present invention, the depression 301 in the cylinder head is disposed along a plane Y, which is situated lower to another plane X comprising a cylinder head wall 303 which forms the encompassing boundary of the cylinder head in the vicinity of the depression 301. The at least one detector (not shown) disposed in the plane Y is always protected by the cylinder head wall 303 that is disposed in a higher plane X. Further, the at least one detector disposed in the plane Y also ensures that the at least one detector member does not project out of the cylinder head 102 and thus, is

protected from being hit by the surrounding objects and even during handling of the engine assembly and also during assembling into the vehicle.
[00051] 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 the light of above disclosure. Therefore, within the scope of claims of the present subject matter, the present disclosure may be practiced other than as specifically described.

We claim:
1. An engine assembly (100) for a vehicle (200), said engine assembly (100)
comprising:
a cylinder block (101);
a cylinder head (102) disposed on said cylinder block (101);
a cylinder head cover (109) configured to enclose at least a portion of said
cylinder head (102);
one or more ports (103, 106) disposed in said cylinder head (102), said
one or more ports (103, 106) include at least one intake port (106) and at
least one exhaust port (103); and
at least one detecting member (105) for detecting one or more gaseous
component emitted from said one or more ports (103, 106),
wherein, said exhaust port (103) includes an originating portion (103a), an emerging portion (103b), and an exhaust path (103ca) traversing from said originating portion (103a) to said emerging portion(103b), said emerging portion (103b) includes a locus point (107) sandwiched at the mating surface between said at least one exhaust port (103) and an exhaust pipe (104), said at least one detecting member (105) includes a detecting portion (105a) disposed ahead and upstream of said locus point (107).
2. The engine assembly (100) as claimed in claim 1, wherein said at least one exhaust port (103) attached adjoiningly to said exhaust pipe (104) include an outer circumferential surface (108a, 108b) including an increasing curve (108a) in the at least one exhaust port (103) side, said curved structure (108a, 108b) is elevated at said locus point (107).
3. The engine assembly (100) as claimed in claim 1, wherein said exhaust path (103ca) is adjoiningly connected to a continuous exhaust path (103cb) disposed inside said exhaust pipe (104) attached adjoiningly to said at least one exhaust port (103).
4. The engine assembly (100) as claimed in claim 1, wherein at least a portion of said cylinder head (102) disposed at a close proximity to said at least one

exhaust port (103) includes a depression (301) configured to receive said at least one detecting member (105).
5. The engine assembly (100) as claimed in claim 1, wherein said cylinder
. head cover (109) includes a 'C shaped contour (302) configured to
substantially enclose at least a portion of said at least one detecting member (105).
6. The engine assembly (100) as claimed in claim 1, wherein said at least one detecting member (105) includes a top most portion (105Tp) disposed below an axis (PPS) passing through said cylinder head cover (109).
7. The engine assembly (100) as claimed in claim 1, wherein said at least one detecting member (105) is disposed at an offset to an axis (PP') passing through said cylinder head cover (109).
8. The engine assembly (100) as claimed in claim 4, wherein said depression (301) is disposed in a plane Y situated lower to another plane X comprising a cylinder head wall (303).
9. The engine assembly (100) as claimed in claim 1 or claim 2, wherein said outer circumferential surface (108a, 108b) is disposed with respect to said detecting portion (105a) such that a horizontal component (HZ) passes through said locus point (107) and said detecting portion (105a) is a tangent to said outer circumferential surface (108a, 108b).
10. The engine assembly (100) as claimed in claim 1 or claim 3, wherein said at least one detecting member (105) includes a central axis (105b) disposed at an angle to said horizontal component (HZ).
It. The engine assembly (100) as claimed in claim 4 or claim 5, wherein said depression (301) includes at least a portion disposed in line with said 'C shaped contour (302), said 'C shaped contour (302) includes a shape in conformation with at least a portion of said at least one detecting member (105).
12. The engine assembly (100) as claimed in claim 4, wherein said depression (301) includes a threaded hole (301H) configured to receive said detecting portion (105a) of said at least one detecting member (105).

13. The engine assembly (100) as claimed in claim 10, wherein said angle includes a range of 0 degrees to 90 degrees.