EXHAUST GAS PURIFYING DEVICE
FIELD OF THE INVENTION
[0001] The present subject matter relates generally to an exhaust gas
> purifying device, and more particularly, but not exclusively to, a device for
purifying exhaust gases let out of an internal combustion engine in an automotive
vehicle.
BACKGROUND OF THE INVENTION
[0002] A conventional two wheeled vehicle is powered by an internal
) combustion engine generally disposed at a lower half of the vehicle. This engine converts chemical energy into mechanical energy by combustion of air-fuel mixture within a combustion chamber of the engine. The said engine, among other components, has a cylinder comprising a cylinder head atop or in front of the cylinder and receiving a reciprocating piston from the bottom or the rear. On
> combustion of the air-fuel mixture (also called combustible charge), the piston
___. transfers theenergy generated during combustion to a crankshaft through a ,_ connecting rod thereby driving the crankshaft which then drives the wheel through a transmission system. The gases left after the combustion exit from the engine through an exhaust port in the form of exhaust gases.
) [0003] Conventionally, anexhaust gas purifyingdevice (or EGP device) is
operatively connected to the internal combustion engine to control the emissions

produced by the engine by injecting secondary air near to an exhaust port. The exhaust gases contain large quantities of unburned gases including carbon monoxide and other hydrocarbons. The secondary air, abundant in oxygen, is added at a place close enough to the exhaust port where exhaust gases still have a high temperature. The added air completes the combustion of any unburned hydrocarbons by oxidising them (known as afterburning) and also converts carbon monoxide into carbon dioxide. Thus the supply of secondary air to the engine can be helpful in reducing the emissions of unwanted gas constituents.
[0004] Conventionally, an EGP deviceis disposed on a vehicle frame
along with a separate air filter and it is co-fastened along with the air filter. The exhaust gas purifying device is connected to a cylinder head assembly of the internal combustion engine through a conduit and provides fresh air (or secondary air) into the conduit to allow fuller combustion of exhaust gases released after combustion of air-fuel mixture. Through the oxidation of outgoing exhaust gases, the emission of harmful exhaust gases containing carbon monoxide and urburnt hydrocarbons into the environment can be reduced, more particularly during cold start conditions. In an automotive vehicle, the device is positioned in a manner that it is concealed from an onlooker.
[0005] However, it is to noted that the volume of required secondary air
varies with respect to the engine capacity. A bigger engine will emit more exhaust gases and hence need more secondary air volume to keep exhaust emissions within the permissible limits. Similarly, a small engine will emit less exhaust gases and would need less secondary air. The EGP device used for a bigger

engine is unusable in a smaller engine as it will inject more secondary air into the exhaust system which is undesirable in the small engine. Further, the conventional mechanical EGP devices do not have a flow control mechanism. They are designed and operated with flow range values depending on the engine vacuum.
[0006] On the other hand, electronic EGP devices are available but they
need an electronic control unit depending upon the vehicle capability. They are costlier and hence increase the cost of ownership in low priced automotive vehicles. Additionally, depending upon the engine, the mechanical EGP device requires different packaging and modifications to becomedeployable across different products including a motorcycle and a scooter type motorcycle.
SUMMARY OF THE INVENTION
[0007] Therefore, the secondary air supply to the exhaust system needs to
be controlled so that same EGP device can be used across different engine configurations while maintaining the flow volume required in the exhaust system. The same EGP device need not be replaced from product to product or engine to engine thereby making the assembly process easy and lead to horizontal deployment of parts across categories. Controlling the flow volume would also help in making the EGP device compliant to stricter emission norms.The present invention is aimed at overcoming the challenges associated with a conventional EGP device and regulate the air flow volume in the device without changing the design of the EGP device so that same EGP device can be used across varying engine specifications and product ranges.

[0008] To this end, the present invention discloses an automotive vehicle
having an exhaust gas purifying device comprising a reed valve, an air cut valve, an air filter wherein a supplementary member having a through hole is provided in the path of the secondary air from the reed valve to an exhaust system of the vehicle. According to an aspect, the supplementary member is disposed into a secondary air carrying hoseconnecting the reed valve to the exhaust system. According to another aspect, the supplementary member is disposed into asecondary air outlet provided in the reed valve.
[0009] The foregoing objectives and summary is provided to introduce a
selection of concepts in a simplified form, and is not limiting. To fully appreciate these and other objects of the present subject matter as well as the subject matter itself, all of which will become apparent to those skilled in the art, the ensuing detailed description of the subject matter and the claims should be read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[00010] The above and other features, aspects, and advantages of the
subject matter will be better understood with regard to the following description and accompanying drawings where:
[00011] FIG. 1 is a side view of an automotive vehicle exemplified by a
conventional motorcycle.

[00012] FIG. 2 shows a detailed side view of an exhaust gas purifying
device disposed on the motorcycle and operatively connected with an internal combustion engine.
[00013] FIG. 3(a) shows a detailed perspective view of the exhaust gas
purifying device according to an embodiment of the present invention.
[00014] FIG. 3(b) shows a sectional view of a secondary air carrying hose
of FIG. 3(a).
[00015] FIG. 4(a) and 4(b) respectively show a perspective view and
sectional view of the exhaust gas purifying device according to a second embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[00016] The present invention, therefore, proposes to disclose an exhaust
gas purifying device operatively connected to an internal combustion engine which is configured to control the flow of air into the exhaust system using a simple mechanical means. In order that those skilled in the art can understand the present invention, the invention is further described below in detail so that various features of the invention thereof proposed here are discernible from the description thereof set out hereunder. However these descriptions and the appended drawings are only used for those skilled in the art to understand the objects, features, and characteristics of the present invention and not to be used to confine the scope and spirit of the present invention. The present subject matter would now be described in greater detail in conjunction with the figures in the

following description.The description is to be understood as an exemplary embodiment and reading of the invention is not intended to be taken restrictively.The EGP device is installed on an automotive vehicle. In an embodiment, the automotive vehicle is a two wheeled saddle type motorcycle. However, the. embodiments disclosed herein can also be practiced in a scooter type motorcycle, with a floorboard or a step through space, or a moped. For the sake of ease of illustration, the ensuing description uses an automotive vehicle exemplified in the form of a motorcycle.
[00017] FIG. 1 shows a side view of a conventional motorcycle capable of
accommodating the present subject matter. The vehicle M comprises a body frame assembly made up of a number of tubes welded together. The vehicle M has a steerable front wheel 11 and a driven rear wheel 12. The body frame primarily includes a head pipe 1 disposed at a front end of the body frame, a main tube 18 running across the longitudinal axis of the vehicle M and enclosed by several vehicle components, and a down tube 2. A front fork 3 is connected to the head pipe 1 through any known type of suspension system for the front wheel and rotatably carries the front wheel 11. The head pipe 1 supports a steering shaft (not shown) disposed inside the head pipe 1. The upper and lower ends of the steering shaft are fixed on an upper bracket and an under bracket (both not shown). The front end of the main tube 18 and an upper end of the down tube 2 are connected to the head pipe 1. The down tube 2 extends obliquely downward in front of an engine 15 from the head pipe 1 whereas the main tube 18 extends rearward from the front end thereof.

[00018] A front fender 4 is provided below the under bracket to avoid the
vehicle and its occupants from being splashed with impurities including mud, water, wet soil and the like. Similarly, a rear fender 17 is provided proximately to the rear wheel 12. A fuel tank 5 is disposed above the main tube 18for storing the fuel for propelling the vehicle M. A seat 6 for a driver and a pillion is further provided, with the said seat 6 being placed behind the fuel tank 5 and rearwardly of the main tube.
[00019] The anterior portion of the motorcycle placed forward to the fuel
tank 5 comprises of a headlamp assembly, the headlamp assembly further comprising a headlamp 8 and a visor 7 placed forward to a handlebar assembly. The handle bar assembly further comprises of a handle bar 9 extending transversely to the vehicle and several control switches for various vehicle operations.
[00020] The said vehicle M is powered by the internal combustion engine
15 disposed below the main tube 18 and supported by the down tube 2. The engine may be liquid-cooled or air-cooled. Drive force output from the engine 15 is transmitted to the rear wheel 12 through a transmission system 16. The rear wheel 12 revolves about a sprocket splined shaft (or axle) 13. The axle 13 is supported at each end by a swing arm 14, the swing arm in turn pivotally connected to the body frame of the vehicle M by a suspension 10. Generally a saddle type vehicle may use any of the two arrangements for rear suspensions, namely dual suspension and mono suspension. However the present vehicle is exemplified through a dual suspension system.Both suspensions in the suspension

system are fixed at their upper ends to the vehicle frame and at their lower ends to the swing arm 14.
[00021] FIG. 2 illustrates a detailed view of an EGP device mounted to the
vehicle frame. The EGP device 25 is supported on the vehicle frame in a front portion of the said motorcycle M. It is mounted below the fuel tank 5. Hence, a substantial portion of the EGP device 25 is not visible to an onlooker. The EGP device 25 is connected to anEGP device mounting bracket 20 which in turn is supported on a frame reinforcement bracket 19. The frame reinforcement bracket 19 is provided between the interjection of the main tube 18 and the downtube 2. In an embodiment, the frame reinforcement bracket 19 is welded to the main tube 18 and the downtube 2.
[00022] The EGP device 25 is operatively connected to the internal
combustion engine 15. It is explained in more detail using FIG. 3(a). The EGP device comprises of a reed valve 27, an air-cut valve 26, an air filter 28 and several conduits for connecting the said valves to other elements. The reed valve 27 is a one way check valve which is opened by a negative pressure of a pressure wave of the exhaust gas. It connects the EGP device with an exhaust pipe of the exhaust system. It permits the secondary air to flow into the exhaust system but does not permit the exhaust gases to escape into the atmosphere through it. The air-cut valve 26 restricts the flow of the secondary air to the exhaust system during deceleration or high vacuum conditions. It prevents excessive air from entering into the exhaust gas passage. The EGP device intakes atmospheric air which is filtered by the air filter 28. The air intake by the EGP device 25 is routed

through an air inlet hose29open on one side towards the atmosphere. This fresh air is fed into the air filter 28 which filters the air.
[00023] As shown in FIG. 2and 3(a), the air cut valve 26 is connected to an
intake pipe 21 through an air cut hose 33. The intake pipe 21 carries the air-fuel
> mixture from a metering device 22 to the combustion chamber of the. engine
through an intake port. The air cut valve senses the engine vacuum through the air
cut hose 33 to cut off fresh air from EGP device to enter into the exhaust system.
[00024] The reed valve 27 is connected to the exhaust system through a
secondary air carrying hose 31 which is covered by a rubber member 30 at its ) conjunction point with the reed valve 27. The reed valve 27 has a secondary air outlet 35 to which the secondary air carrying hose 31 is joined. When the exhaust pressure is higher than the atmospheric pressure, the reed valve27 in the EGP device closes and reverse flow of the exhaust air is precluded. The secondary air carrying hose 31 carries the secondary air from the EGP device to the exhaust
> system, more particularly the exhaust pipe.
[00025] According to an aspect, a supplementary member 34 having a
through hole41 is provided in the path of the secondary air from the reed valve 27 to an exhaust system of the vehicle. In an embodiment, the secondary air carrying hose 31 is provided with a supplementary member 34 having a through ) hole 41. The supplementary member 34 is inserted into the secondary air carrying hose 31 and the secondary air carrying hose 31 is then joined to the secondary air outlet 35 of the reed valve 27. A cross sectional view of the assembled secondary

air carrying hose 31 is shown in FIG. 3(b), The through hole 41 of the supplementary member 34 controls the volume of the air flow of secondary air.
[00026] In a second embodiment of the EGP device as shown in FIG 4(a)
and 4(b), the supplementary member 34 is inserted into the secondary air outlet 35 of the reed valve 27. The secondary air carrying hose 31 is then joined to the secondary air outlet 35.
[00027] According to an aspect of the present invention, the supplementary
member 34is removable / detachable. It is just inserted into the desired location and can be removed. In an embodiment, the supplementary member is made of any material from a group consisting of plastic resin or heat resistant material.
[00028] In an embodiment, the thickness of supplementary member is in
the range between 1 to 7 mm.
[00029] In both the embodiments, the supplementary member 34 controls
the flow of secondary air by controlling the diameter of the flow path. The flow volume of secondary air passing through the reed valve 27 to the exhaust system is controlled by the through hole of the supplementary member 34. The inner diameter of the supplementary member 34 can be varied depending upon the requirement to control the air flow. Thus, the same EGP device can be used across various engine configurations and vehicle models as it would require just the insertion of the supplementary member 34 with the desired diameter of the through hole into the secondary air carrying hose 31 or the secondary air outlet 35. The diameter depends upon the engine specification and flow volume

required.This requires less development time and is extremely inexpensive compared to designing of a new EGP device altogether. By controlling the flow volume, nitrogen oxide emissions can be reduced by the EGP device. Thus, the same EGP device with different supplementary member of required diameter can be used across product ranges and engine specifications. It provides an inexpensive means to control the flow volume in the EGP device.
[00030] The present subject matter is thus described. The description is not
intended to be exhaustive nor is it intended to limit the invention to the precise form disclosed. It will be apparent to those skilled in the art that the disclosed embodiments may be modified in light of the above description. The embodiments described are chosen to provide an illustration of principles of the invention and its practical application to enable thereby one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. Therefore the forgoing description is to be considered exemplary, rather than limiting, and the true scope of the invention is that described in the appended claims.

We claim:
1. An automotive vehicle (M) having an exhaust gas purifying device (25) operatively connected to an internal combustion engine and comprising a reed valve (27), an air cut valve (26), an air filter (28) wherein a supplementary member (34)having a through hole (41) is provided in the path of the secondary air from the reed valve (27) to an exhaust system of the vehicle.
2. The vehicle as claimed in claim 1, wherein the supplementary member (34) is disposed into a secondary air carrying hose (31) connecting the reed valve (27) to the exhaust system.
3. The vehicle as claimed in claim 1, wherein the supplementary member (34) is disposed into asecondary air outlet (35) provided in the reed valve (27). :
4.. The vehicle as claimed in claim 1, wherein the supplementary member (34) is removable.
5. The vehicle as claimed in claim 1, wherein the supplementary member (34) is made of any material including a group consisting of plastic resin and heat resistant material.
6. The vehicle as claimed in claim 1, wherein the diameter of the through hole (41) of the supplementary member (34) is in the range between 1mm to 7mm.