DESC:FIELD OF INVENTION
[001] The present invention is generally related to an exhaust system for a vehicle and, more particularly to mounting of a catalytic converter used for purifying exhaust gases.
BACKGROUND
[002] Conventionally, in a vehicle exhaust system, a catalytic converter is provided for purifying the exhaust system arranged in an exhaust path connected to an exhaust port of an engine to a muffler on a rear portion of a vehicle body. The catalytic converter is an apparatus installed in the exhaust system to reduce the toxicity of exhaust gases. Generally, catalytic converters use catalysts such as platinum, palladium, or rhodium to oxidize carbon monoxide and unburned hydrocarbons, and reduce oxides of nitrogen and eliminate up to 97% of carbon monoxide (CO) and hydrocarbon (HC) emissions. The catalytic converter is designed to perform at least the pre-defined distance coverage of a vehicle.
[003] The catalytic converter provided in the exhaust system of a two-wheeled vehicle forms part of the exhaust pipe and mounted at certain position and orientation w.r.t the vehicle’s engine. In the case of substantially vertical engine, the exhaust pipe typically starts from the exhaust port of the engine, transverses substantially downward along front side of the engine and further extends in a substantial horizontal and rearward direction along the vehicle’s length with a bending portion between the substantially downward and rearward portion. The exhaust pipe is further connected to the muffler to expel the exhaust gases. The catalytic converter in the exhaust pipe may be positioned in the substantially downward portion or at a bending portion or at a horizontal rearward portion after the bending portion.
[004] Generally, the exhaust pipe comprises an upstream portion, such as, a part of exhaust pipe between the exhaust port and the catalytic converter, and a downstream portion, such as, a part of exhaust pipe between the catalytic converter and the muffler outlet. Based on the available space, engine orientation and other components, position of the catalytic converter is decided. The catalytic converter comprises a mesh type structure similar to honeycomb and is housed in a casing. In certain scenarios, predominantly when the catalytic converter is positioned near the bending portion of the exhaust pipe, catalytic converter (CAT) failure occurs at a shorter distance (half of a pre-defined distance) than the pre-estimated distance coverage. Distinguishing between the short-lived catalytic converter and a full-term catalytic converter, it was observed that the failure of the CAT was mainly observed at the entry portion of the CAT. This leads to complete failure of the CAT despite having majority of the areas still functional. This is because of hot exhaust gases directly hit the entry area of the CAT at high velocity especially when the CAT is placed near bending portion. It is also reported that in such a failure, a complete catalytic converter needs to be replaced.
[005] Thus, presently there is a need in the art for a device that prevents premature deterioration at the inlet region of the catalytic converter, thereby reducing the risk of catalytic failure and effectively addressing the aforementioned challenges described above.
OBJECT OF THE INVENTION
[006] An object of the present disclosure is to ameliorate limitations of the existing prior art by providing an improved design of a catalytic converter (CAT) of an exhaust system of a two-wheeled vehicle.
[007] Another object of the present disclosure is to decrease the deterioration of the catalytic converter for increasing the life of the CAT.
[008] Yet another object of the present invention is to protect an entry area of the CAT from deterioration.
[009] Another object of the present invention is to reduce failure in the CAT before a pre-defined time period.
[010] 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
[011] With these objectives in view, the present invention provides an exhaust system for a vehicle comprising, an engine as a drive source for the vehicle, an exhaust pipe connected to the engine to carry exhaust gases to an atmosphere. The exhaust pipe comprises at least a first pipe portion extending from an exhaust port of the engine, a second pipe portion connected to a muffler and a catalytic converter (CAT) used to purify the exhaust gases and is configured to carry the exhaust gases from the first pipe portion to the second pipe portion. The CAT is connected to the first pipe portion using at least a connecting member and the connecting member is overlapping at least an inner portion of catalytic converter.
[012] In an embodiment the present invention, the connecting member joins a rear end of the first pipe portion and a frontal end of the second pipe portion.
[013] In an embodiment the present invention, the second pipe portion forms a cover for the CAT.
[014] In an embodiment the present invention, the connecting member is concentric with the catalytic converter. The connecting member has a converging profile along the flow of the exhaust gases towards the second pipe portion.
[015] In an embodiment the present invention, the connecting member is a ring type or collar type member having plurality of resting flanges for attaching the first pipe portion, the second pipe portion and at least a slot for mounting the catalytic converter. The resting flanges include a front flange for connecting the rear end of the first pipe portion, a rear flange for connecting the frontal end of the second pipe portion, and a rear slot for connecting a peripheral portion of the catalytic converter.
[016] In an embodiment the present invention, a ratio of annular thickness of the connecting member to an outer diameter of the CAT is in a range of 0.05 to 0.10. A length of the peripheral portion of the CAT overlapped by the connecting member is up to 15% of total length of the CAT.
[017] In an embodiment the present invention, the second pipe has a varying cross-section along a length of the pipe ranging from circular to elliptical.
[018] In an embodiment the present invention, the first pipe, second pipe and the CAT may be connected using known connecting processes such as welding processes, such as MIG welding, CO2 welding, or can be connected through a snap fit or a threaded fit arrangement.
[019] In an embodiment the present invention, the connecting member connects a rear end of the first pipe portion and the second pipe portion is connected to the rear portion of the CAT using connecting or mounting means such as welding or snap fit or threaded fit arrangement.
[020] In an embodiment of the present invention, the exhaust system is employed in a two-wheeled vehicle comprising a single cylinder engine. The first pipe portion is connected to the exhaust port of the engine and transverses rearward and downward, and the CAT is connected to the first pipe portion near the downward portion of the engine or at a rearward side of the engine and connected to the second pipe portion.
[021] In an embodiment of the present invention, the exhaust system is employed on any vehicle including two-wheeled, three-wheeled and four-wheeled vehicle.
BRIEF DESCRIPTION OF DRAWINGS
[022] 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:
[023] Fig. 1 illustrates a representative view of an exemplary engine and an exhaust system in accordance with the present disclosure;
[024] Fig. 2a illustrates an isometric view of the exemplary exhaust system, according to an embodiment of the present disclosure;
[025] Fig. 2b illustrates an isometric exploded view of the exemplary exhaust system in accordance with the present disclosure;
[026] Fig. 3 illustrates a portion of the exemplary exhaust system in accordance with the present disclosure; and
[027] Fig. 4 illustrates another portion of the exemplary exhaust system in accordance with the present disclosure.
LIST OF REFERENCE NUMERALS:
100 – Engine
150 – Exhaust system
102 – Exhaust pipe
104 – Muffler
106 – Catalytic converter (CAT)
106a – Peripheral Portion of CAT
108 – First pipe portion
108a – Frontal end of first pipe portion
108b – Rear end of the first pipe portion
110 – Second pipe portion
110a – Frontal end of second pipe portion
110b – Distal end of second pipe portion
112 – Connecting member
114 – Converging profile
116 – Front flange
118 – Rear flange
120 – Slot
122 - Inner portion of Catalytic Converter
DETAILED DESCRIPTION
[028] 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.
[029] 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.
[030] Fig. 1 illustrates a representative view of an exemplary engine (100) and an exhaust system (150) in accordance with the present disclosure. The engine (100) for a vehicle is provided with the exhaust system (150). The exhaust system (150) comprises an exhaust pipe (102) connected to a muffler (104). The engine (100) is the drive source for the vehicle. The exhaust pipe (102) is configured to carry the exhaust gases generated during operation of the engine (100) to the muffler (104). The muffler (104) is configured to further expand the exhaust gases in order to attenuate airborne noise of the engine (100) and expel the exhaust gases to the atmosphere. The exhaust system (150) preferably comprises a catalytic converter (CAT) (106) to reduce the harmful pollutants from exhaust gases and emit less polluted gas. In an embodiment, the CAT (106) is fitted in the exhaust pipe (102) before the muffler (104). The number of CATs (106) and their position may vary based on engine’s configuration and requirements, for instance, additional CATs (106) may be provided in the exhaust pipe (102) and within the muffler (104).
[031] Figs. 2a and 2b illustrate further details of the exhaust system (150) in accordance with the present disclosure. The exhaust pipe (102) is connected to an exhaust port (not shown) of the engine (100) through suitable means likes flange. The exhaust pipe (102) is connected to the engine (100), the exhaust pipe (102) comprising at least a first pipe portion (108) extending from an exhaust port of the engine (100), a second pipe portion (110) extending towards the muffler (104), and the catalytic converter (106) used to purify the exhaust gases and configured to carry the exhaust gases from the first pipe portion (108) to the second pipe portion (110). The CAT (106) is connected to the first pipe portion (108) using at least a connecting member (112). The connecting member (112) overlaps at least an inner portion of the catalytic converter (122).
[032] In an embodiment of present invention, the first pipe portion (108) includes a frontal end (108a) and a rear end (108b). The frontal end is connected to the exhaust port and the rear end (108b) is present at a distal end from the exhaust port. Further, the second pipe portion (110) includes a frontal end (110a) and a distal end (110b), such that the frontal end (110a) is in proximity to the connecting member (112) and the distal end (110b) is positioned at a point where the muffler (104) is connected. The connecting member (112) joins the rear end (108b) of the first pipe portion (108) and the frontal end (110a) of the second pipe portion (110). The CAT (106) is covered by the portion of the second pipe portion (110).
[033] Fig. 3 and 4 illustrates a sectional view of the connecting member (112), in an embodiment of present invention, the connecting member (112) is a concentric with the catalytic converter (106). The connecting member (112) has a converging profile (114) along the flow of the exhaust gases towards the second pipe portion (110). The connecting member (112) is a ring type or a collar type member having a plurality of flanges (116, 118) for attaching the first pipe portion (108), the second pipe portion (110) and at least a slot (120) for mounting the catalytic converter (106). The resting flanges include a front flange (116) for connecting the rear end (108b) of the first pipe portion, a rear flange (118) for connecting the frontal end (110a) of the second pipe portion (110), and a rear slot (120) for connecting the catalytic converter peripheral portion (106a).
[034] In an embodiment of the present invention, the first pipe portion (108), the second pipe portion (110) and the CAT (106) may be connected using known connecting processes such as welding processes, particularly MIG welding, CO2 welding. The method used for joining different pipe portions and CAT (106) of the exhaust system (150) includes the following steps: firstly the peripheral portion (106a) of the catalytic converter (106) is joined in the rear slot (120) of the connecting member (112) using a welding process (at X). A tolerance of 1 mm is given between a slot height (h) and a wall thickness (w) of the catalytic converter (106). Secondly, the second pipe portion (110) is moved from the rear side of the catalytic converter (106), and the frontal end (110a) of the second pipe portion (110) is joined with the rear flange (118) of the connecting member (112). Thereafter, a complete welding (at Y) is performed at the joinery of the rear flange (118) of the connecting member (112) and the frontal end (110a) of the second pipe portion (110). Thirdly, the rear end of the first pipe portion (108b) is moved from the front towards the first flange (116) of the connecting member (112) and welding (at Z) is performed at the joinery. Hence, the connecting member (112) is joined with the first pipe portion (108), the second pipe portion (110) and the peripheral portion (106a) of the catalytic converter (106) and thus forms a leakproof joinery. In an embodiment of the present invention, the connecting member (112) connects the rear end of the first pipe portion (108b) and the second pipe portion (110) is connected to the rear portion of the CAT (106) using a connecting or a mounting means such as a welding or a snap fit or a threaded fit.
[035] In a preferred embodiment of the present invention, the position of the converging profile (114) of the connecting member (112) facilitates in preventing the exhaust gases from hitting a particular portion of the catalytic converter (106), such as, at entry of the catalytic converter (106) and further making the flow of the exhaust gases uniform through the entry of the catalytic converter (106). Hence, the deterioration at the peripheral portion (106a) of the catalytic converter (106) is prevented. This led to improving the lifespan of the catalytic converter (106) and thus the catalytic converter (106) performs for at least the pre-defined distance coverage of the vehicle. For optimum performance of the connecting member (112), the converging profile (114) is designed such that the ratio of annular thickness (t) of the connecting member (112) to the diameter (D) of the CAT (106) is in the range of 0.05 to 0.10. Further, the length of the peripheral portion of the CAT (106a) is overlapped by the connecting member (112) up to 15% of the total length (L) of the CAT (106).
[036] According to preferred embodiment of present invention, the second pipe portion (110) has a varying cross-section along the pipe length ranging from circular to elliptical. Further, the connecting member (112) may be located at different location w.r.t the engine’s orientation. For instance, it be located at any bending portion occurring in the exhaust pipe (102). Therefore, the number of connecting members (112) and its location defined herein are not to limit the scope of present invention.
[037] In an embodiment of the present invention, a two-wheeled vehicle comprises a single cylinder engine (100). Further, the first pipe portion (108) is connected to the exhaust port of the engine (100) and transverses rearward and downward, and the CAT (106) is connected to the first pipe portion (108) near the downward portion of the engine (100) or at a rearward side of the engine (100) and connected to the second pipe portion (110). In an embodiment, the exhaust system (150) is employed on a three-wheeled vehicle or a four-wheeled vehicle.
[038] Although the present invention has been described in terms of certain preferred embodiments, various features of separate embodiments can be combined to form additional embodiments not expressly described. Moreover, other embodiments apparent to those of ordinary skill in the art after reading this disclosure are also within the scope of this invention. Furthermore, not all the features, aspects and advantages are necessarily required to practice the present invention. Thus, while the above detailed description has shown, described, and pointed out novel features of the invention as applied to various embodiments, it will be understood that various omissions, substitutions, and changes in the form and details of the apparatus or process illustrated may be made by those of ordinary skill in the technology without departing from the spirit of the invention. The inventions may be embodied in other specific forms not explicitly described herein. The embodiments described above are to be considered in all respects as illustrative only and not restrictive in any manner.
,CLAIMS:1. An exhaust system (150) for a vehicle comprising:
an engine (100);
an exhaust pipe (102) connected to the engine (100) to carry exhaust gases to the atmosphere, the exhaust pipe (102) comprising at least a first pipe portion (108) extending from an exhaust port of the engine (100), a second pipe portion (110) connected to a muffler (104);
a catalytic converter (CAT) (106) to purify the exhaust gases, wherein the CAT (106) is configured to carry exhaust gases from the first pipe portion (108) to the second pipe portion (110), the CAT (106) is connected to the first pipe portion (108) using at least a connecting member (112); wherein the connecting member (112) is overlapping at least an inner portion of catalytic converter (122).
2. The exhaust system (150) for a vehicle as claimed in claim 1, wherein the connecting member (112) is configured to connect a rear end of the first pipe portion (108b) and a frontal end of the second pipe portion (110).
3. The exhaust system (150) for a vehicle as claimed in claim 1, wherein the second pipe portion (110) forms a cover for the CAT (106).
4. The exhaust system (150) for a vehicle as claimed in claim 1, wherein the connecting member (112) is configured to be concentric with the CAT (106).
5. The exhaust system (150) for a vehicle as claimed in claim 1, wherein the connecting member (112) has a converging profile (114) along the flow of exhaust gas towards the second pipe portion (110).
6. The exhaust system (150) for a vehicle as claimed in claim 1, wherein the connecting member (112) is a ring type or a collar type member having a plurality of resting flanges for attaching the first pipe portion (108), the second pipe portion (110) and at least a slot (120) for mounting the CAT (106).
7. The exhaust system (150) for a vehicle as claimed in claim 6, wherein the resting flanges include at least a front flange (116) for connecting a rear end of the first pipe portion (108b) and a rear flange (118) for connecting a frontal end of the second pipe portion (110a), and a rear slot for connecting a peripheral portion of CAT (106a).
8. The exhaust system (150) for a vehicle as claimed in claim 1, wherein a ratio of annular thickness of the connecting member (112) to an outer diameter of the CAT (106) is in a range of 0.05 to 0.10.
9. The exhaust system (150) for a vehicle as claimed in claim 7, wherein a length of the peripheral portion of CAT (106a) overlapped by the connecting member (112) within rear slot is up to 15% of total length of the CAT (106).
10. The exhaust system (150) for a vehicle as claimed in claim 1, wherein the second pipe portion (110) has a varying cross-section along a pipe length ranging from circular to elliptical.
11. The exhaust system (150) for a vehicle as claimed in claim 1, wherein the first pipe portion (108), the second pipe portion (110) and the CAT (106) are integrally connected using connecting processes including welding processes comprising MIG welding and CO2 welding.
12. The Exhaust system (150) for a vehicle as claimed in claim 1, wherein the first pipe portion (108), the second pipe portion (110), and the CAT (106) are connected through a snap fit or a threaded fit.
13. The exhaust system (150) for a vehicle as claimed in claim 1, wherein the connecting member (112) connects a rear end of the first pipe portion (108b) and the second pipe portion (110) connected to the rear of the CAT (106) using a mounting means.
14. The exhaust system (150) for a vehicle as claimed in claim 1, wherein the exhaust system (150) is employed in a two-wheeled vehicle comprising a single cylinder engine (100), the first pipe portion (108) is connected to the exhaust port of the engine (100) and transverses rearward and downward, and the CAT (106) is connected to the first pipe portion (108) near the downward portion of the engine (100) or at a rearward side of the engine (100) and connected to the second pipe portion (110).
15. The exhaust system (150) for a vehicle as claimed in claim 1, wherein the exhaust system (150) is employed in a three-wheeled vehicle or a four-wheeled vehicle.