DESC:FIELD OF INVENTION

[001] The present invention relates to the field of exhaust system arrangement and more particularly relates to an oxygen sensor mounting arrangement with associated assembly.

BACKGROUND OF INVENTION

[002] Effective environmental pollution control is currently one of the biggest need and internal combustion (IC) engines is one of the contributor to Air pollution. Hence there is need to monitor and control the emissions from IC engines in vehicles. Various methods are available for controlling the emissions of engine, one of which is to monitor and control the air-fuel ratio. If a stoichiometric air- fuel ratio is not balanced then there is a higher possibility of incomplete combustion of air-fuel mixture in engine which results in emitting unburned carbon and other polluted gases. Therefore, the air-fuel mixture needs to be completely combusted inside engine for reduced pollution contains. The fuel mixture inside engine is completely combusted or not can be determined from leftover oxygen (O2) content in the exhaust gas. If the O2 content are more that indicates the unburned contents are more and the mixture is not completely combusted. The O2 content in the exhaust gas can be measured using an Oxygen (O2) or lambda sensor. Modern electronic fuel injection system helps in controlling the air-fuel ratio in engine based on the measurements taken by O2 sensor.

[003] A conventional exhaust system of two-wheeled vehicle comprises an exhaust pipe, Oxygen (O2) sensor and a catalytic converter (CAT). O2 sensor helps in monitoring the oxygen content in the exhaust gas while the CAT helps to make the exhaust gas less pollutant through chemical reactions. The O2 sensor is mounted after exhaust port of the engine to measure the O2 contents in the untreated exhaust gas. After O2 sensor the gas flows further through the exhaust pipe and is passed through the muffler which comprises the CAT. The exhaust gas gets treated at the CAT and the less polluted gases are finally sent to the atmosphere. In some of the prior exhaust systems the CAT is also mounted outside of muffler, after O2 sensor in exhaust pipe.

[004] The position of oxygen sensor plays an important role in its measurement accuracy. It should be positioned at a place where the maximum amount of O2 content is present in order to have best results, also the sensor needs to be heated to get activated. Temperature of exhaust gases is at peak near exhaust port which helps in heating the sensor quickly and controlling of air-fuel ratio can be immediately initiated once the engine is started. Therefore, it is always recommended to mount the oxygen sensor near exhaust port of the engine for better accuracy and quick activation.

[005] The position of CAT is also an important aspect from its efficiency and life perspective. In prior art exhaust system there are two types of CAT positions disclosed. In one of the prior art system the CAT is mounted outside the muffler while in other system the CAT is positioned inside the muffler of exhaust system. Similar to O2 sensor the CAT also needs to be heated to get activated or start operating which is done from the heat of exhaust gases. In both of the prior arrangement the CAT is mounted away from the engine. The major disadvantage of mounting the CAT away from the exhaust port or engine is temperature of exhaust gases reduces till it reaches the CAT, therefore it takes longer time to heat the CAT and activate after engine is started.

[006] In the prior exhaust system where CAT is mounted inside the muffler one end of the exhaust pipe is connected to the exhaust port of engine and the other end is connected to the muffler using soft metallic gasket. Muffler is typically supported by a frame of vehicle. As there exists a connection between engine, exhaust pipe, muffler and frame so any dimensional variation in this arrangement causes a misalignment at exhaust pipe to Muffler joint leading to the leakage of untreated gas from the system. Similarly the outside air can flow inside the exhaust system through the leakages. The air leaked into the system may increase Oxygen contents in exhaust gas and disturbs normal chemical reactions in CAT which reduces its emission reduction efficiency. Therefore, mounting the CAT away from engine is disadvantageous as it firstly delays the activation of CAT and secondly there is a possibility of exhaust gas leakage if CAT is mounted into the muffle.

[007] To overcome the disadvantageous describe hereinabove the CAT and O2 sensor are recommended to be mounted near engine or exhaust port to have better accuracy, life and efficiency. There are various arrangements available which disclose mounting of O2 sensor near exhaust port. However the major challenge is the heat and the energy of exhaust gas is maximum near engine and it gets directly acted upon the CAT and O2 sensor, which is not desirable for their life. The energy of exhaust gas comprises both static and dynamic pressure forces. In case of engine misfires the energy and the heat is very high which can cause mechanical and thermal damage of CAT and O2 sensor.

[008] Also, it is always recommended to mount the O2 sensor directly in the flow path of exhaust gases to have accurate reading and emission control. However; by keeping the sensor in the exhaust flow the chances of thermal and mechanical damage increases. The position of O2 sensor on the connecting piece is designed such that the exhaust gas flow near periphery of O2 sensor is adequate enough such that it will not damage the O2 sensor as well as does not hamper sensing efficiency of O2 sensor.

[009] There are numerous amount of oxygen sensor arrangements available such that mounting the oxygen sensor on cylinder head, exhaust pipe, exhaust port and other connecting parts etc. Mounting the sensor in cylinder head can be a complex as well as costly method since the cylinder head design has to be modified to accommodate the sensor. Mounting the sensor in the exhaust pipe can be a convenient, easy and less costly method. However the oxygen sensor is generally mounted inclined at certain angles the inclined mounting of oxygen sensor becomes difficult in exhaust pipe as proper alignment has to be done. Also the area around the sensor mounting becomes weak and be susceptible to damage or leakage. The other option is to mount the sensor on a connecting parts such as mouthpiece, connecting pipes which connects the exhaust port and the exhaust pipe. However, as explained above the sensor cannot be placed near exhaust port as the sensor is susceptible to heat and energy of exhaust gases. Thus, there is a need to have a system where Oxygen sensor along with CAT is positioned near to engine or exhaust port and also capable to handle the energy and heat of exhaust gas such that it does not damage the CAT and O2 sensor and also does not deteriorate the efficiency /life of sensor and CAT.
OBJECTIVES OF THE INVENTION
[010] In light of the aforementioned, it is an objective of this invention to provide a convenient way of mounting oxygen sensor and CAT near exhaust port of an engine.

[011] Another objective of the present invention is to ensure that the oxygen sensor and CAT will not get damaged due to the energy and heat of exhaust gases.

[012] Still another objective of the invention is to provide an arrangement to obtain better performance of the oxygen sensor and CAT without damage.

[013] Other objects and advantages of the present disclosure will be more apparent from the following description when read in conjunction with the accompanying figures, which are not intended to limit the scope of the present disclosure
SUMMARY OF THE INVENTION
[014] With these objectives in view, the present invention provides an exhaust system connected to an exhaust port of an engine comprising:
a coupling assembly;
a connecting piece
at least an oxygen sensor;
at least a catalytic convertor (CAT);
an exhaust pipe;
a muffler,
connected to each other, characterised in that;
said coupling assembly is mounted on the exhaust port of the engine;
said connecting piece mounted on the coupling assembly;
said catalytic convertor (CAT) connected to an outlet end of connecting piece;
said exhaust pipe is connected to an outlet end of the CAT;
said muffler connected to end of the exhaust pipe;
wherein; the connecting piece is having varying dimension at its inlet side and outlet side and is arranged near exhaust port such that the resultant force (F) of exhaust gas is resolved in a horizontal (FH) and a vertical force component (FV) and the horizontal force component (FH) is larger than the vertical force component (FV) and wherein at least an oxygen sensor is mounted on to said connecting piece.

[015] As one of the embodiment, the shape of the connecting piece is such that it has at least a wall having tapered shape and at least another wall having straight shape provided opposite to the tapered wall such that both the wall extends in the downward direction of the exhaust port.

[016] The shape of the connecting piece is such that it has at least a wall of tapered shape is having a concave surface on inner side of the connecting piece.

[017] The shape of connecting piece is such that the dimensions of the area between inlet side of connective piece and outlet side is varying.

[018] The connecting piece is arranged such that the horizontal force component (FH) of exhaust gas is directed towards the tapered wall of the connecting piece.

[019] The oxygen sensor mounted on the connecting piece such that the sensing part of the oxygen sensor is offset to a centreline of direction of flow of exhaust gas.

[020] The connecting piece comprises a hole and an O2 sensor connector is welded on the hole for positioning O2 sensor.

[021] The oxygen sensor mounted on the connecting piece is inclined at acute angle to the horizontal plane.

[022] According to one of the embodiment the connecting piece is formed of plurality of pieces connected together such that it forms a suitable O2 sensor mounting arrangement.

[023] The catalytic convertor (CAT) is connected to the connecting piece using a CAT connector.

[024] The coupling assembly comprises a mouthpiece gusseted inside the exhaust port of engine; a flange provided on mouthpiece having mounting arrangement for mounting the exhaust system engine; and a pipe passing through the flange and having one end connected to the mouthpiece and other end connected to the connecting piece provided for directing the exhaust gas towards the connecting piece.

[025] According to another embodiment of the present invention the exhaust system (200) comprises second Oxygen sensor and second CAT mounted in the exhaust pipe.
BRIEF DESCRIPTION OF DRAWINGS
[026] The proposed invention related to an oxygen sensor and CAT mounting arrangement which will now be described with the help of accompanying drawings, in which:

[027] Figure 1 illustrates the overall arrangement of exhaust system including oxygen sensor, CAT, exhaust pipe and muffler according to one of the prior art.

[028] Figure 2 illustrates the overall arrangement of exhaust system including oxygen sensor, CAT, exhaust pipe and muffler according to one of the embodiment of present invention.

[029] Figure 3 illustrates an isometric view of the coupling assembly, connecting piece and O2 sensor, CAT in assembled condition according to the present invention.

[030] Figure 4 illustrates isometric side view of the assembly illustrating the oxygen sensor mounting angles and offset position according to present invention.

[031] Figure 5 illustrates the cross-sectional side view of the assembly indicating the force reactions acting on the wall of the connecting piece according to present invention.

[032] Figure 6 illustrates the velocity flow path of exhaust gas according to present invention.

[033] Figure 7 illustrates the relation or position of overall exhaust system with oxygen sensor w.r.t. vehicle according to present invention.
DETAILED DISCRIPTION OF DRAWINGS:
[034] A preferred embodiment will now be described in detail with reference to the accompanying drawings. The preferred embodiment does not limit the scope and ambit of the disclosure. The description provided is purely by way of example and illustration.

[035] The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments 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. The system and method of the present disclosure will be described herein below with reference to FIGURES 1 to 6.

[036] Figure 1 represents the conventional exhaust system (100) of two-wheeled vehicle having single cylinder engine according to one of the prior art. The system comprises an exhaust pipe (101), an oxygen sensor mounting arrangement (102) and a muffler or silencer (103) which comprises a catalytic converter (CAT) (104). One end of the exhaust pipe (101A) is connected to an engine exhaust port. Typically Oxygen (O2) sensor (102) is mounted after the first bend in the exhaust pipe (101). As explained in the background section this arrangement has disadvantages like the CAT (104) and O2 sensor (102) takes more time to start operating and has low efficiency since the CAT (104) and O2 sensor (102) are mounted away from exhaust port. To overcome these disadvantages the O2 sensor (102) and CAT (104) are positioned near exhaust port however it has various other challenges mainly concerning reduced life due to thermal and mechanical damages as explained in background section.

[037] Figure 2 represent the improved exhaust system (200) and associated arrangement for mounting Oxygen (O2) sensor (202) and catalytic convertor (CAT) (204) according to one of the embodiment of present invention. The proposed arrangement is preferably used for two-wheeled vehicle preferably having single cylinder engine (210). Proposed arrangement enables to overcome the disadvantages cited of the conventional system through the use of specially designed connecting piece (206). The arrangement comprises a coupling assembly (208) which preferably consists of a mouthpiece (302), a pipe (306) and a flange (304). However; the coupling assembly (208) is not limiting to said arrangement and all the conventional coupling assembly can be used in the proposed arrangement. The specially designed connecting piece (206) is provided on said coupling assembly (208) to connect the connecting piece (206) with the exhaust port (211) of engine (210). The connecting piece (206) is of diverging shape from inlet to outlet and positioned near to exhaust port (211) of engine (210). Dimensions at the inlet portion (206A) is different than the dimensions at the outlet side (206B) of the connecting piece (206). Similarly according to alternate embodiment the area between inner and outer end is provided with varying dimensions. The inlet side (206A) of the connecting piece is from where exhaust gas enters the connecting piece and outlet side (206B) is from where the gas flows outside the connecting piece (206). The shape of the connecting piece (206) is such that it causes exhaust flow to change its direction where CAT (204) is mounted, preferably in the downward direction. A suitable arrangement for mounting oxygen sensor (310) is provided on the connecting piece (206). The outlet end (206A) of the connecting piece (206) is connected to the CAT (204) using a CAT connector (308). The outlet end (204B) of the CAT (204) from where the exhaust gas flows out from CAT (204) is connected to the exhaust pipe (212). The muffler (214) is connected to the end of the exhaust pipe using suitable clamping arrangement (215). This completes the exhaust system (200) of the vehicle and the exhaust gases finally flows out to atmosphere from muffler (214).

[038] Figure 3 represents the close isometric view of the complete assembly illustrating the O2 sensor location (310) on the connecting piece (206) along with coupling assembly (208) which comprises mouthpiece (302), flange (304) and the pipe (306). The mouthpiece (302) goes inside the exhaust port (211), preferably gusseted to an inner wall of the exhaust port (211). The flange (304) is mounted on the mouthpiece (302) having appropriate connection means for connecting the complete exhaust assembly (200) to the exhaust port (211) in cylinder head of the engine (210). The coupling assembly (208) further comprises a pipe (306) which goes inside the mouthpiece (302) and preferably welded. The pipe portion (306) is a small circular section onto which the connecting piece (206) is fitted. Mouthpiece (302), flange (304), pipe (306) and the connecting piece (206) are preferably welded to each other to form an integral assembly.

[039] Figure 4 illustrates isometric side view of the assembly indicating position of O2 sensor (202). The sensor (202) is preferably mounted inclined on the connecting piece (206) using an O2 sensor connector (310). The inclined position of O2 sensor (202) is such that the axis of O2 sensor (202A) is at an acute angle with the horizontal plane (202B) as indicated in figure 4. A hole is bored on the connecting piece (206) and the connector (310) is welded into the hole. The connector can be optionally provided with a threated boss (not shown) into which the O2 sensor (202) can be mounted. In an alternative embodiment the connecting piece (206) can be formed of multiple parts preferably two. Two parts are then preferably welded to each other to form the complete connecting piece (206). Optionally the two parts of the connecting piece (206) are provided with a protrusion such that when the two parts are welded to each other the protruding part form the connector (310) which can be used for mounting the Oxygen sensor (202). By providing a separate inclined O2 sensor connector (310) into the connecting piece (206), the difficulty of providing the inclined hole on the exhaust pipe (101) as explained in background section is overcome by providing the hole on the connecting piece (206) instead.

[040] It is always recommended to mount the O2 sensor (202) directly in the exhaust flow in order to have better efficiency. However; if the O2 sensor (202) is placed directly in the flow then the chance of damage increases due to direct impact of energy and heat. Hence it is proposed to mount the O2 sensor (202) offset to the direction of exhaust flow (402) as illustrated in figure 4. The offset is a distance between centerline of exhaust gas flow and the sensing point of O2 sensor (202) as indicated by (406) in the figure 4. The connecting piece (206) has suitable arrangement for offset mounting of O2 sensor (202). The connecting piece (206) is mounted near to exhaust port (211) this helps in achieving the advantages of placing the sensor (202) near exhaust port (211) such as increased efficiency, quick start etc. The offset position (406) helps to avoid the energy and heat of the exhaust gas receiving directly at the O2 sensor (202) especially in the event of engine misfire during which maximum heat and energy gets generated. The disadvantage of placing the sensor (202) offset is it may reduce the sensing efficiency since the amount of gases flowing over sensor reduces due to offset position. To overcome this the connecting piece (206) is designed such that the efficiency of the O2 sensor (202) is not hampered due to offset position (406). The position of O2 sensor (202) on the connecting piece (206) is designed such that the exhaust gas flow near periphery of O2 sensor (202) is adequate enough such that it will not damage the O2 sensor (202) as well as does not hamper sensing efficiency of O2 sensor (202). The design of connecting piece (206) and its associated advantages are explained hereinafter.

[041] Figure 5 represents a cross-sectional side view of the exhaust system showing coupling assembly (208), connecting piece (206) and CAT (204) assembled to each other. The connecting piece (206) is designed such that the effective radius at inlet (206A) is smaller as compare to an effective radius at outlet (206B) of connecting piece (206). The figure 5 illustrates shape of the connecting piece (206) according to one of the embodiment. The connecting piece (206) is mounted on the pipe (306) of the coupling assembly (208). At least one wall of the connecting piece (206) is having a tapered shape (506) at suitable angle. While the opposite wall is made straighter (508) to direct the gas towards CAT (204). Both the walls (506, 508) extends towards downward direction from inlet (206A) to outlet (206B) thereby making the connecting piece (206) of diverging shape. The shape of the tapered (506) wall is not limiting to the straight taper shape but alternatively it can also comprise a curvature preferably of concave shape or a negative curvature at its inner surface. Similarly the straight shape (508) is defined as a straight shape along vertical plane with +/- 10 degrees. The exhaust port (211) and the connecting piece (206) are positioned such that the high pressure exhaust gas coming out of exhaust port (211) flows in the inclined downward direction and is directed to hit the tapered wall (506) of the connecting piece (206). The pipe (306) of the coupling assembly (208) directs the flow of exhaust gas. The high pressure gases hits the tapered wall (506) and is forced to move towards the inner side of the connecting piece (206) i.e. towards opposite straighter wall (508), this movement creates a swirl and the gases gets dispersed within a connecting piece (206). Also it helps in achieving better uniformity index of CAT (204). The swirl created in the connecting piece (206) allows the gas to flow over the Oxygen sensor (202) which is mounted slightly offset from the flow of gas. Diverging shape of connecting piece (206) also reduces the velocity of gas and allows the gas to stay over the sensor (202) and CAT (204) for longer period. Hence even though the sensor (202) is mounted offset to the flow still due to the proposed arrangement and associated swirl the accuracy of O2 sensor (202) is not hampered. . In case of engine misfiring event the major amount of energy gets absorbed by the tapered wall (506) of connecting piece (206) thereby the overall energy of the gas gets reduced. The gas with the reduced energy then flows over the sensor (202). Further, as the O2 sensor (202) is mounted offset to the direction of flow of exhaust gas such that the high pressure energy and heat is not directly applied on sensor thereby protecting it from damage without compromising on its sensing efficiency.

[042] The tapered portion (506) forces the gas to change its direction preferably in downward direction and the diverging portion reduces the possibility of any back pressure. Therefore, the gases after hitting the connecting piece (206) moves in the downward direction where the CAT (204) is installed. The figure 5 indicates that due to proposed arrangement the resultant force (F) of the exhaust gas if resolved in vertical (FV) and horizontal (FH) components as shown in the figure 5 then the horizontal component (FH) of force (F) is large as compare to a vertical force component (FV). This indicates that the major amount of force which is horizontal component (FH) first hits the tapered wall (506) where most of its energy gets absorbed. The downward or vertical force component (FV) is very less in comparison which is the direct force acting on the CAT (204). Since the vertical component (FV) is very less, the amount of direct force acting on CAT (204) is very low. Therefore, by this arrangement the CAT (204) is protected from high energy of the exhaust gases even though it is placed near exhaust port (211). At the same time since it is placed near exhaust port (211) the hot gases can still flow through CAT (204) which helps to get the CAT heated very quickly and start operating.

[043] The common phenomena of traveling around curved path is the velocity of the mass on moving across inner curvature is lower as compare to the velocity of mass flowing along outer curvature due to the difference in the radius of curvature. This phenomena is also applicable in the exhaust flow system where the exhaust gas flows across the curvature present in the exhaust system. As illustrated in the figure 6 when the gas flows along the curvature its particles flowing along the inner curve (602) path moves at lower velocity as compare to particles moving along outer curvature path (604). This creates poor uniformity index and gives inaccurate reading at oxygen sensor (202) as the gas on outer surface (604) moves quickly. In order to overcome the above lacuna the connecting piece (206) is provided with the tapered wall (506) at outer surface while a straight wall (504) at inner surface of connecting piece (206). This forces the gas to first hit the tapered wall (506) where the flow of gas gets disturbed and moves towards opposite straight surface (508) of the connecting piece (206). This movement creates a swirl in the gas; thereby the gas slowing along outer surface doesn’t pass on quickly as it hits the tapered wall (506). This allows proper gas mixing and helps in achieving better uniformity index which gives improved results.

[044] Figure 7 illustrates the relation or position of exhaust system of present invention w.r.t. vehicle more particularly figure 7 illustrates position of oxygen sensor w.r.t. vehicle. The vehicle is a two wheeled vehicle however; the system according to the present invention is not vehicle specific and may be applied any vehicle.

[045] According to another embodiment of the present invention the exhaust system can be provided with multiple Oxygen sensors preferably two. At least one sensor (202) is mounted at a position as explained hereinabove and the other sensor can be mounted at a position after CAT (204) or near muffler (214) at the end of exhaust pipe (212) or at any other suitable location. Similarly, additional CATs can be provided in the exhaust system for better efficiency preferably two. The first CAT (204) is mounted at a position as explained hereinabove and the second CAT can be mounted at a suitable distance from the first CAT (204) in the exhaust system (200). Size or dimensions and other properties of two CAT can vary depending on the requirement.
ADVANTAGES OF THE INVENTION
[046] Technical advancements of the system envisaged by the present disclosure include the realization following advantages:
1. A system that reduces the damage of oxygen sensor and catalytic convertor (CAT) even though it is mounted near exhaust port thereby increasing their life.
2. A system that improves the accuracy of oxygen sensor thereby improving emission control.
3. A system that provides a convenient arrangement for mounting the Oxygen sensor and CAT.
[047] Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps. The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.

[048] The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.

[049] 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 preferred 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.

Dated this on 10th December, 2018

For Bajaj Auto Limited

Milind Joshi
Sr. Manager (R&D) ,CLAIMS:1. An exhaust system connected to an exhaust port of an engine comprising:
a coupling assembly;
a connecting piece;
at least an oxygen sensor;
at least a catalytic convertor (CAT);
an exhaust pipe;
a muffler;
connected to each other characterized in that;
said coupling assembly is mounted on the exhaust port of the engine;
said connecting piece mounted on the coupling assembly;
said catalytic convertor (CAT) connected to an outlet end of the connecting piece; and
said exhaust pipe is connected to an outlet end of the CAT;
said muffler connected to end of the exhaust pipe;
wherein; the connecting piece is having varying dimension at its inlet side and outlet side and is arranged near exhaust port such that the resultant force (F) of exhaust gas is resolved in a horizontal (FH) and a vertical force component (FV) and the horizontal force component (FH) is larger than the vertical force component (FV) and wherein at least an oxygen sensor is mounted on to said connecting piece.

2. An exhaust system as claimed in claim 1 wherein; the shape of the connecting piece is provided with at least a wall having tapered shape and at least another wall having straight shape provided opposite to the tapered wall such that both the wall extends in the downward direction of the exhaust port.

3. An exhaust system as claimed in claim 2 wherein; the wall of tapered shape is having a concave surface on inner side of the connecting piece.

4. An exhaust system as claimed in claim 2 wherein; the shape of connecting piece is such that the area at inlet side of connecting piece is smaller than the area at outlet side.
5. An exhaust system as claimed in claim 4 wherein; the connecting piece is made of plurality of parts welded together.

6. An exhaust system as claimed in claim 2 wherein; the connecting piece is connected to the exhaust port such that the horizontal force component (FH) of exhaust gas is directed towards the tapered wall of the connecting piece.

7. An exhaust system as claimed in claim 1 wherein; the oxygen sensor is mounted on the connecting piece such that the sensing part of the oxygen sensor is offset to a centreline of direction of flow of exhaust gas.

8. An exhaust system as claimed in claim 1 wherein; the connecting piece comprises a hole and a connector is welded on the hole for positioning oxygen sensor.

9. An exhaust system as claimed in claim 1 wherein; the oxygen sensor mounted on the connecting piece is inclined at acute angle to the horizontal plane.

10. An exhaust system as claimed in claim 1 wherein; the connecting piece is connected to the catalytic convertor (CAT) using a CAT connector.

11. An exhaust system as claimed in claim 1 is connected to the exhaust port of the engine using a coupling assembly comprising:
a mouthpiece gusseted inside the exhaust port;
a flange provided on mouthpiece having mounting arrangement for mounting the exhaust system; and a pipe passing through the flange and having one end connected to the mouthpiece and other end connected to the connecting piece.
Dated this on 10th December, 2018

For Bajaj Auto Limited

Milind Joshi
Sr. Manager (R&D)