DESC:FIELD OF INVENTION
[001] The present invention relates to a vehicle and more particularly relates the exhaust system for the vehicle.
BACKGROUND OF INVENTION
[002] Effective environmental pollution control is currently one of the biggest need of hour. Vehicles operated on internal combustion (IC) engine is one of the contributor to air and noise pollution. Hence there is need to monitor and control the emissions from IC engines in vehicles. The exhaust system plays crucial role in controlling environmental pollution from vehicle. Generally, an exhaust system is designed to collect the burnt gases from the Internal Combustion engine, remove the toxic and/or harmful elements from it, reduce the noise level and expel the filtered exhaust gases (which comply with the emission standards) to the environment.

[003] The exhaust system comprises of an exhaust pipe connected to an engine exit, to carry exhaust gases to a muffler from where it is further treated & expelled to atmosphere. Additionally the exhaust system is provided with a catalytic converter (CAT), used to remove the harmful and toxic elements from the exhaust gases using combination of precious metal elements namely Pd (palladium), Pt (platinum), and Rh (rhodium). The number and position of the CAT may vary based on engine configuration and requirements.

[004] In addition to removal of harmful elements from the exhaust gas, the exhaust system specifically muffler, also helps in reducing engine noise. Muffler also plays an important role in engine performance by creation of back pressure. Generally, the muffler comprises of plurality of chambers created through baffles for guiding exhaust gas between chambers. The number and volume of chambers are decided considering the output noise level (in dB) and the engine performance to be achieved. The movement of exhaust gases through chambers, obstructions and perforated tubes leads to reduction in energy of the exhaust gases and reduction in the generated noise. Conventionally, the mufflers are provided with three chambers.

[005] To measure unburnt oxygen content in the exhaust gases an oxygen sensor is provided. The sensor measures the residual oxygen content of the exhaust gases and then transmits a signal to the control unit in the form of a signal to detect whether the mixture is too lean or rich. The control unit controls the A/F ratio to achieve the desired engine performance. Conventional exhaust system included single oxygen sensor to manage the emissions from the vehicle. However, to evaluate the performance of CAT two oxygen sensors are mounted at locations i.e. before the CAT and after the CAT. The two oxygen sensors can detect the unburnt oxygen content of the exhaust before it enters the CAT, and then compare it to the unburnt oxygen content of the exhaust as it leaves the CAT to evaluate the performance of CAT.

[006] According to one of available solutions, the second CAT is located inside the muffler and a problem has been observed for mounting of additional O2 sensor within muffler after second CAT. The major disadvantage with mounting of the sensor inside the muffler is, it will affect the sealing capacity of the muffler. Further, in case of malfunctioning/ serviceability it would be a challenging task to remove the second oxygen sensor being inside the muffler. During manufacturing it needs puncturing of a hole in the muffler, which requires expensive dies. The system also increases manufacturing time.

[007] In three-wheeled vehicle, the exhaust system is assembled on the vehicle assembly line, in which it is mounted on the cross member of the vehicle. Due to the space constraint, it becomes difficult for workers on assembly line to properly hold the exhaust system from two sides and mount it on the cross-member. It increases assembling time due to the current structure of the muffler, as one end of the muffler doesn’t has any proper structure to which worker can hold to for mounting the exhaust system on the vehicle. In existing vehicle, the exhaust system is mounted on vehicle body. One of the disadvantage of mounting the exhaust system/ muffler on vehicle body (cross-member) is the vehicle vibrations as well as engine vibrations are transferred to the muffler, thereby leading to failure of mounting provision of exhaust system. This leads to deterioration of NVH of the vehicle and frequent replacement leading to increases cost.

[008] Additionally, space is a constraint in a compact vehicle like three wheeled vehicle. The existing muffler mounted on vehicle body is large in size leading to more weight and volume. In order to address the issue, when the muffler is made compact by decreasing size, it effects the NVH and engine performance. Therefore, it is required to design a compact muffler with optimum design of chambers with doesn’t affect the NVH and engine performance of vehicle.

[009] Hence, in view of above problems of existing systems there is a clear need to provide an improved exhaust system providing a convenient mounting provision for an additional oxygen sensor and which is of compact design, low cost, easy to manufacture and service.

OBJECTIVES OF THE INVENTION:
[010] In light of the aforementioned, it is an objective of this invention to provide a convenient location of mounting an additional oxygen sensor on the exhaust system.

[011] Another objective of the present invention is to ease manufacturing of exhaust system.

[012] Yet another objective of the invention is to provide ease of serviceability and accessibility.

[013] Still another objective of the invention is to provide a compact sized muffler.

[014] Another objective of the present invention is to reduce the manufacturing cost of the exhaust system.

[015] 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
[016] With these objectives in view, the present invention provides an exhaust system for a vehicle comprising:
an exhaust pipe connected to an engine to carry gases to atmosphere; comprising at least a first pipe portion and a second pipe portion;
a muffler covering at least a part of the second pipe portion;
wherein the second pipe portion has at least a U-shape portion;
wherein the U-shape portion is outside the muffler.

[017] According to one of the embodiment, the U-shape portion comprises a provision for mounting at least an oxygen sensor.

[018] The first pipe portion is connected to first side of the muffler and the U-shape portion of the second pipe portion is on second side of the muffler.

[019] The U-shape portion is further extended into the muffler to direct the exhaust gases to the muffler through a perforated portion of exhaust pipe.

[020] According to one of the embodiment, the muffler comprises plurality of chambers, preferably two chambers with volume of first chamber in the range of 60 to 80% of the total volume of the muffler.

[021] The chambers are formed using at least one baffle comprising at least an opening for allowing exhaust gases to flow from first chamber to second chamber, wherein the opening is provided with a guiding bracket for directing the flow of exhaust gases in second chamber. Preferably, perpendicular to the longitudinal axis of the muffler.

[022] The muffler is provided with a tail pipe to expel exhaust gases from the second chamber to atmosphere.

[023] The muffler comprises a plate preferably within first chamber, provided to support the muffler.

[024] According to one of the embodiment of present invention, the exhaust system comprises at least a catalytic converter (CAT) provided within first pipe portion. Preferably, at least a second CAT is provided within a second pipe portion within the muffler.

[025] According to one of the embodiment of the present invention, a first oxygen sensor is provided on the first pipe portion.

[026] According to another embodiment of the present invention, the muffler is provided with at least a mounting bracket for mounting the muffler. Preferably, the muffler is mounted on a crankcase of the engine.

[027] The exhaust system according to present invention is employed on any vehicle including two-wheeled, three-wheeled and four-wheeled vehicle.

BRIEF DESCRIPTION OF DRAWINGS
[028] The above and other objects, features, and advantages of the present disclosure will be more apparent from the detailed description taken in conjunction with the accompanying drawings. One or more embodiments of the present invention are now described, by way of example only with reference to the accompanied drawings wherein like reference numerals represent like elements:

[029] Fig. 1 illustrates an isometric three-dimensional view of an engine with exhaust system, according to an embodiment of the present disclosure;

[030] Fig. 2a illustrates an isometric three-dimensional view of the exhaust system, according to an embodiment of the present disclosure;
[031] Fig. 2b illustrates an isometric three-dimensional view of the exhaust system of Fig. 2a from rear side, according to an embodiment of the present disclosure;

[032] Fig. 3a illustrates an isometric three-dimensional view illustrating details of muffler of the exhaust system of Fig. 2a, according to an embodiment of the present disclosure;

[033] Fig. 3b illustrates a side view of the exhaust system of Fig. 3a, according to an embodiment of the present disclosure;

[034] Fig. 4 illustrates an isometric three-dimensional view illustrating details of muffler of the exhaust system of Fig. 2a, according to an embodiment of the present disclosure;

[035] Fig. 5a illustrates a side view of mounting arrangement of the exhaust system on the engine, according to an embodiment of the present disclosure;

[036] Fig. 5b illustrates an isometric three-dimensional view of mounting arrangement of the exhaust system on the engine of Fig. 5a from rear side, according to an embodiment of the present disclosure;

[037] Fig.6 illustrates a rear view of vehicle with the exhaust system employed in a three wheeled vehicle, according to an embodiment of the present disclosure.

DETAIL DESCRIPTION OF DRAWINGS:
[038] 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.

[039] It will be readily understood that components of present invention as generally described and illustrated in figures herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the invention as represented in the figures is not intended to limit the scope of the invention but is merely representative of certain examples of presently contemplated embodiments in accordance with the invention. The presently described embodiments will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout.

[040] Fig. 1 illustrates an engine (100) for an automotive vehicle provided with an exhaust system (150); wherein the exhaust system (150) comprises of an exhaust pipe (101) connected to a muffler or casing (105). The exhaust pipe (101) is configured to carry the exhaust gases generated during operation of the engine (100) to the muffler (105). The muffler (105) is configured to further expand the exhaust gases in order to attenuate airborne noise of engine (100) and further improve the engine performance through creation of back pressure. The exhaust system (150) preferably comprises a catalytic converter (CAT) (102) to reduce the harmful pollutants from exhaust gases and emit less polluted gas. In present embodiment, the CAT (102) is fitted in the exhaust pipe (101) before the muffler (105). The number of CATs and their position may vary based on engine configuration and requirements for example, additional CATs may be provided in exhaust pipe (101) and within the muffler (105).

[041] Figs. 2a to 4, illustrating further details of the exhaust system (150) according to one of the embodiment of present invention. The exhaust pipe (101) is connected to an exhaust port (not shown) of the engine (100) through suitable means (125) likes flange. The first pipe portion (101a) is connected to the muffler (105) to carry exhaust gases from the engine (100) to the muffler (105). The first pipe portion (101a) is mounted on first side of the muffler (105) through suitable means such as flange. The first pipe portion (101a) is provided with a first CAT (102) preferably mounted near exhaust port of engine (100) to treat the exhaust gases for reducing toxic pollutants. The position and number of CATs may vary. The first pipe portion (101a) is provided with a first oxygen sensor (O2 Sensor) (115) mounted close to the exhaust port, in order to measure the unburned oxygen contents in the exhaust gases. There may be an additional O2 sensor mounted within the first pipe portion (101a) to evaluate performance of first CAT (102).

[042] The second pipe portion (101b) is substantially covered by the muffler (105). Preferably, a second CAT (240) is provided within the second pipe portion (101b). There may be additional CATs provided within the second pipe portion (101b) in muffler (105). Further, the second pipe portion (101b) is extended outside the muffler (105) in U-shape portion (101c). The extended U-shape portion (101c) is on the second side of the muffler (105). The exhaust gases, flows through the U-shape portion (101c) and again enters into the muffler (105). According to an important aspect of present invention, a second O2 sensor (120) is mounted on the U-shape extended portion (101c). The arrangement for mounting second O2 sensor (120) helps in solving various problems related to existing systems such as O2 sensor need not be mounted within muffler and there is no need to puncture the muffler for mounting O2 sensor (120), thereby avoiding need of any expensive dies such as deep draw die for manufacturing. It is also easier to hold the assembly and mount the O2 sensor (120) during manufacturing, thereby reducing significant manufacturing time. The present system also helps in retaining better sealing capability of the muffler (105), thereby drastically reducing the sealing cost. As the O2 sensor (120) is mounted outside the muffler (105) it is easily accessible for any replacement or servicing purpose.

[043] Further, the exhaust gases enters into the muffler (105) for further expansion and noise attenuation through a perforated portion (101d) of exhaust pipe (101). As the exhaust pipe is extended outside the muffler, it may increase overall size of the exhaust system (150) and muffler (105). In order to compensate for this, the overall muffler (105) size is reduced in the present invention and made compact. This advantageously helps in reducing weight of the exhaust system (150). However; with the compact muffler (105) it is difficult to achieve the NVH characteristics and engine performance. In order to achieve the necessary performance characteristics the muffler (105) is provided with plurality of chambers (105a, 105b) formed using a baffle plate (105d). Preferably, the muffler (105) is provided with two chambers (105a, 105b) optimized to achieve necessary performance, such that the first chamber (105a) is of higher volume as compared to second chamber (105b). Preferably, the volume of first chamber is 60% to 80% of the total volume of the muffler (105) i.e. the volume of second chamber (105b) is only of 20% to 40% of the total volume of the muffler (105). By having large first chamber (105a) it is possible to achieve higher first expansion of the gases.

[044] The perforated portion (101d) of the exhaust pipe (101) further helps in achieving the noise attenuation. The baffle (105d) is in a form of a plate having an opening for allowing the gases to flow from the first chamber (105a) to the second chamber (105b) in a controlled manner. Additionally, a guiding bracket (300) is provided on the opening of the baffle (105d), to direct the gases in a direction perpendicular to the longitudinal axis of the muffler (105). This feature helps in controlled expansion of gases in second chamber (105b) and helps in improving NVH characteristics of the exhaust system/ vehicle. The muffler (105) is further strengthen by providing at least one plate (105c). The muffler (105) is completely closed with sealing from sides using side plates. Finally, the treated exhaust gas is expelled from muffler (105) to atmosphere through a tail pipe (135).

[045] Referring to Figs. 5a-5b, illustrating mounting arrangement of the exhaust system (150) according to preferred embodiment of the present invention. The complete system is mounted on the engine (100), preferably on an engine crankcase (100c) using mounting brackets (215) provided on the muffler (105). The exhaust system (150) is preferably bolted on the crankcase (100c). Though, the exhaust system (150) may also be mounted on the vehicle body part, it is preferred to mount the exhaust system (150) on the engine (100), as during vehicle operations, vehicle body vibrations are eliminated from getting transferred to the muffler (105) and thereby stopping any failure of mounting brackets (215), which is otherwise a frequent issue in body mounted exhaust systems.

[046] The present invention is applicable to any type of vehicle including two-wheeled, three wheeled or four wheeled vehicle including front mounted and rear mounted engines (100). Fig. 6 illustrates a three wheeled vehicle (600) with the exhaust system (150) mounted towards rear side of vehicle.

[047] According to preferred embodiment of present invention, the O2 sensors may be of non-heated or heated type; wherein the heated type O2 sensor is electrically heated. The exhaust pipe (101) is defined in different portions herein for sake of convenience; however, each portion may be formed by different pipes or portions connected together through suitable means such as welding. Therefore, the number of portions defined herein are not to limit the scope of present invention.

[048] The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics or essential characteristics. The described embodiments are to be considered in respects as illustrative and not restrictive.

[049] Although the exemplary forms of the present disclosure have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the present disclosure.
,CLAIMS:1. An exhaust system (150) for a vehicle comprising:
an exhaust pipe (101) connected to an engine (100) to carry gases to atmosphere; comprising at least a first pipe portion (101a) and a second pipe portion (101b);
a muffler (105) connected to the first pipe portion (101a) and covering at least a part of the second pipe portion (101b);
wherein the second pipe portion (101b) has at least a U-shape portion (101c) and the U-shape portion (101c) is provided outside the muffler (105).

2. The exhaust system (150) for vehicle as claimed in claim 1, wherein the U-shape portion (101c) comprises a provision for mounting at least an oxygen sensor (120).

3. The exhaust system (150) for vehicle as claimed in claim 1, wherein the first pipe portion (101a) is connected to first side of the muffler (105) and the U-shape portion (101c) of the second pipe portion (101b) is on second side of the muffler (105).

4. The exhaust system (150) for vehicle as claimed in claim 1, wherein the U-shape portion (101c) is further extended into the muffler (105) to direct the exhaust gases to the muffler (105) through a perforated portion (101d) of the exhaust pipe (101).

5. The exhaust system (150) for vehicle as claimed in claim 1, wherein the muffler (105) comprises at least two chambers (105a, 105b) formed using at least one baffle (105d) comprising an opening for allowing exhaust gases to flow from first chamber (105a) to second chamber (105b).

6. The exhaust system (150) for vehicle as claimed in claim 5, wherein the volume of first chamber is in the range of 60 to 80% of the total volume of the muffler (105).

7. The exhaust system (150) for vehicle as claimed in claim 5, wherein the opening is provided with a guiding bracket (300) for directing the flow of exhaust gases in second chamber (105b).

8. The exhaust system (150) for vehicle as claimed in claim 7, wherein the guiding bracket (300) is provided perpendicular to the longitudinal axis of the muffler (105).

9. The exhaust system (150) for vehicle as claimed in claim 1, the muffler (105) is connected to a tail pipe (135) to expel exhaust gases from the second chamber (105b) to atmosphere.

10. The exhaust system (150) for vehicle as claimed in claim 1, wherein the muffler (105) comprises a plate (105c) provided to support the muffler (105).

11. The exhaust system (150) for vehicle as claimed in claim 1, wherein the exhaust system comprises at least a catalytic converter (CAT) (102) provided within first pipe portion (101a).

12. The exhaust system (150) for vehicle as claimed in claim 11, wherein at least a second CAT (240) is provided within a second pipe portion (101b) within the muffler (105).

13. The exhaust system (150) for vehicle as claimed in claim 1, wherein a first oxygen sensor (115) is provided on the first pipe portion (101a).

14. The exhaust system (150) for vehicle as claimed in claim 1, wherein the muffler (105) is provided with at least a mounting bracket (215) for mounting the muffler (105) on vehicle body part.

15. The exhaust system (150) for vehicle as claimed in claim 14, wherein the muffler (105) is mounted on a crankcase (100c) of the engine.

16. The exhaust system (150) for vehicle as claimed in any one of the preceding claims, the vehicle includes a two-wheeled, a three-wheeled (600) and a four-wheeled vehicle.