MOUNTING STRUCTURE FOR A SECONDARY AIR INJECTION SYSTEM IN A MOTORCYCLE

FIELD OF THE INVENTION

[0001] The present subject matter relates generally to a secondary air injection system, and more particularly, to a mounting structure for a secondary air injection system in a vehicle with swinging power unit.

BACKGROUND OF THE INVENTION

[0002] A secondary air injection system provides a mechanism to control the emissions produced from a vehicle by injecting additional air near to an exhaust port. Usually the exhaust gases contain large quantities of unburned gases including carbon monoxide and other hydrocarbons. If the secondary air abundant in oxygen is added at a place close enough to the exhaust port and where exhaust gases still have a high temperature, the added air can complete the combustion of any unburned hydrocarbons by oxidising them (known as afterburning) and also convert carbon monoxide into carbon dioxide. Thus the supply of secondary air to the exhaust system can be helpful in reducing the emissions of unwanted gas constituents.

[0003] The secondary air injection system usually consists of a reed valve, an air-cut valve, an air filter and conduits for connecting the said valves to other elements. The reed valve is a one way check valve which is opened by a negative pressure of a pressure wave of the exhaust gas. It permits the air to flow into the exhaust system but does not permit the exhaust gases to escape into the atmosphere. The air-cut valve restricts the flow of the secondary air so as to prevent excessive air from entering into the exhaust gas passage such as under power unit idle or high load, high speed conditions. The system draws air from clean side of the air filter.

[0004] Generally such secondary air injection system together with a separate air filter is mounted on the vehicle frame with the help of a bracket and is co-fastened along with the said air filter. The entire system is positioned underneath a side panel of the vehicle above a swinging power unit and hence concealed from an onlooker under this mounting system. Meanwhile, the secondary air injection system is connected to a cylinder head assembly via a conduit.

[0005] However this mounting system and its position lead to several locational and functional problems. The length of the conduit required for connecting the secondary air injection system to the exhaust port of the cylinder head assembly is more as it has to pass sequentially through the frame length, swinging power unit width and the power unit bottom towards the exhaust port. The long conduit increases the cost of manufacturing of the vehicle. Further, the secondary air injection system is disposed underneath the side panel pursuant to assembly of the swinging power unit and its subsequent mounting to the vehicle frame. This requires a separate assembly of the secondary air injection system in a small area which may prove to be inconvenient. Furthermore, due to proximity to the swinging power unit, the conduit may undergo oscillations which may lead to failure of the conduit in the form of breakages and cracks further leading to malfunctioning of the secondary air injection system.

[0006] The present invention is directed to overcome all or any of the problems as set above and obviate a lacunae in the prior art. It is therefore one of the object of this invention to disclose a superior mounting structure for a secondary air injection system for use in a vehicle having a swinging power unit. It is another object of this invention to achieve cost efficiency during the vehicle assembly comprising the secondary air injection system. A further object of the present invention is to improve the durability of the secondary air injection system by providing a proficient mounting structure.

SUMMARY OF THE INVENTION

[0007] To this end, the present subject matter discloses a mounting structure for a secondary air injection system for a vehicle with a swinging power unit, the secondary air injection system comprising a secondary air valve having an integrated reed valve, an air cut valve and a conduit extending from the reed valve to an exhaust pipe of the engine for delivering air to said exhaust pipe, characterized in that the said secondary air injection system is disposed at substantially a central portion on an upper surface of a cooling cowl of the swinging power unit through mounting inserts.

[0008] According to an aspect of the present invention, the said secondary air injection system is connected to an air filter wherein the air filter is separately mounted on the upper surface of the cooling cowl through a holder attached to the cooling cowl. Specifically, the secondary air system and the air filter positioned on the opposite sides of an intake port on the upper surface of the cooling cowl. Meanwhile, the holder and the mounting inserts may be made of any material including plastic resin.

[0009] The foregoing objectives and summary provide only a brief introduction to the present subject matter. 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,

appended claims and accompanying drawings where:

FIG. 1 shows a side view of a typical vehicle with a swinging power unit capable to accommodate the concerned invention.

FIG. 2 shows a top view of a mounting structure of a secondary air injection system according to the present subject matter.

FIG. 3 shows a front view of the mounting structure of the secondary air injection system according to the present subject matter.

FIG. 4 shows a detailed top view of the mounting structure of the secondary air injection system.

FIG. 5 shows a side view of the entire secondary air injection system mounted over the cooling cowl of the swinging power unit.

DETAILED DESCRIPTION OF THE INVENTION

[00011] The subject matter described herein relates to a mounting structure of a secondary air injection system in a vehicle with a swinging power unit. It is to be noted that "front" and "rear", and "left" and "right" wherever referred to in the ensuing description, refer to front and rear, and left and right directions as seen in a state of being seated on a seat of the vehicle. Further, a longitudinal axis, wherever referred to, refers to a front to rear axis relative to the vehicle, while a lateral axis refers generally to a side to side, or left to right axis relative to the vehicle. In the description, the vehicle is a saddle ride type vehicle with a swinging power unit. However it is contemplated that the concepts of the present invention may be applied to other types of vehicles within the spirit and scope of this invention such as a scooter or moped. The term 'motorcycle' includes within its ambit a vehicle with a swinging power unit. Various other features of the mounting structure according to the present subject matter here will be discernible from the following further description thereof, set out hereunder. The detailed explanation of the constitution of parts other than the subject matter which constitutes an essential part has been omitted at suitable places.

[00012] FIG. 2 illustrates a side view of a concerned vehicle with a swinging power unit capable to accommodate the present subject matter. Typically such a vehicle includes a body frame assembly made up of several tubes welded together which usually supports the body of the said vehicle. The vehicle has a steerable anterior wheel 110 and a driven rear wheel 111 driven by driving force generated by the power unit. The body frame assembly 101 of the vehicle is an elongated structure, which typically extends from a forward end to a rearward end of the vehicle. It is generally convex in shape, as viewed from a side elevational view. The body frame assembly 101 includes a head pipe (not shown) and a down pipe that extends downward from the head pipe, and is covered by a plurality of vehicle body covers including a front panel 115, a leg shield 116, an under seat cover 117 and rear panels 112.

[00013] A handlebar assembly 105 and a seat assembly 106 are supported at opposing ends of the frame assembly and a generally open area is defined there between known as floorboard 107 which functions as a step through space. A fuel tank (not shown) that stores fuel supplied to the engine is disposed at the rear end of the vehicle above the rear wheel 111. It is present on the upper side of the power unit along with a fuel tank cap. The seat for a driver and a pillion is placed forward to the fuel tank and rearwardly of the floorboard 107. A muffler is provided to the right side of the rear wheel, and connects to the engine. A side stand fixed to the left side of the body frame supports the vehicle such that vehicle inclines to the left side without falling.

[00014] Typically, a front suspension assembly 103 is operatively positioned between the anterior wheel 110 and the frame assembly. Similarly a rear suspension assembly 114 is operatively positioned between the rear wheel 111 and the frame assembly. The front suspension assembly 103 commonly is a telescopic fork arrangement while the rear suspension assembly 114 is a hydraulic damped arrangement.

[00015] In the said vehicle, the rear suspension swing arm typically supports the power unit which is configured to drive the rear wheel 111 of the vehicle. The power unit is structured such that an engine 102 and a swing case 108, which together form the power unit, are integrally constructed. In an embodiment of the present invention, the engine is a four stroke single cylinder internal combustion engine and the swing case 108 is connected to a left side surface of a crankcase of the engine 102 so as to extend forward.

[00016] It is disposed on the vehicle frame with one end of the swing case 108 attached to the rear wheel hub in such a way that the power unit is substantially angularly disposed to the ground. The engine 102 is arranged horizontally, that is, its crankshaft is placed perpendicularly to the longitudinal direction of the vehicle body. Since the basic construction of an engine is known to those versed in the art, the details have been omitted.

[00017] The rear portion of the vehicle, on both sides of the longitudinal axis, is generally covered on both sides by the rear panels 112. The side panels improve the aesthetic look of the vehicle. A secondary air injection system, indicated generally by the reference numeral 200, is not visible to an onlooker as it is positioned in the space between the rear panels 112.

[00018] A mounting structure of the secondary air injection system 200 according to the present invention is now described. A top view of the mounting structure is shown in FIG. 2 and a front view is shown in FIG. 3. The power unit is surrounded by a shroud with a fan to enhance forced cooling of the power unit.

The shroud present over the power unit is also known as cooling cowl 300 and may be made of plastic resin or the likes. The secondary air injection system 200 in the present invention comprises of a secondary air injection valve 201 and is connected to a small air filter 202. Both of them are attached to the cooling cowl 300.

[00019] According to an aspect of the present invention, the secondary air injection system 200 is disposed at a central portion of the cooling cowl 300 with the help of at least two mounting inserts 203 built in the cooling cowl in such a way that the secondary air injection system 200 is positioned at an upper surface of the cooling cowl 300 facing towards the seat. The mounting inserts 203 secure the secondary air injection system 200 intact over the cooling cowl 300. The secondary air injection valve 201 and the air filter 202 are at some distance to each other and not integrated. The structure is in such a way that the secondary air injection valve 201 is positioned on right side of the longitudinal axis of the vehicle whereas the air filter is positioned along the left side of the same. Specifically, the secondary air system and the air filter are positioned on the opposite sides of an intake port on the upper surface of the cooling cowl 300.

[00020] The air filter 202 consists of pleated paper filter elements (hence popularly known as paper filter) and compact in size unlike a large cylindrical foam filter commonly used. It is mounted on the cooling cowl 300 with the help of preferably a holder 207 or a bracket. An air filter inlet 206 projects out from the said air filter 202 towards the anterior and hang from the cowl 300. The secondary air is derived from the air which has been passed through the air filter 202 and which is thus cleaned. This air is then fed into the secondary air injection valve 201 through an air inlet tube 205. The secondary air injection valve injects this filtered air into the exhaust port via a conduit 204. The addition of secondary air to the exhaust system is helpful in reducing the emissions of unwanted gas constituents. When the exhaust pressure is higher than the atmospheric pressure, the reed valve in the secondary air injection system closes and reverse flow of the exhaust air is precluded. The complete assembled secondary air injection system along with the engine assembly is shown in FIG. 5.

[00021] The present mounting structure removes the necessity of the secondary air injection system to be connected to the frame. The mounting structure of the secondary air injection system on the cooling cowling 300 significantly reduces the length of the conduit 204 connecting the secondary air injection valve 201 to the exhaust port. Hence, it slashes the cost involved with respect to the conduit. Further the entire system along with the air filter can be assembled along with the swinging power unit assembly and hence a separate step to assemble the secondary air injection system is eliminated. Furthermore, the secondary air injection system is located near to the exhaust port over the cooling cowl and utilizes the empty space over the cooling cowl.

[00022] The present subject matter and its equivalent thereof offer many advantages, including those which have been described henceforth. The present invention proposes a cost effective, compact, efficient and better mounting structure for a secondary air injection system. It substantially causes the reduction in mounting space of the air filter connected to the secondary air injection system. The counting structure of the present secondary air injection system is such that the system causes less noise when in operation while still being in a concealed portion of the motorcycle concealed from an onlooker. Further, through this structure, the secondary air injection system does not interfere with the arrangement of other motorcycle parts nor it obstructs the power unit functioning.

[00023] 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. A mounting structure for a secondary air injection system for a vehicle with a swinging power unit, the secondary air injection system comprising a secondary air valve having an integrated reed valve, an air cut valve and a conduit extending from the reed valve to an exhaust pipe of the engine for delivering air to said exhaust pipe, characterized in that the said secondary air injection system is disposed at substantially a central portion on an upper surface of a cooling cowl of the swinging power unit through mounting inserts.

2. The mounting structure for a secondary air injection system as claimed in claim 1 wherein the said system is connected to an air filter, the said air filter being separately mounted on top of the cooling cowl of the swinging power unit through a holder attached to the said cowl.

3. The mounting structure for a secondary air injection system as claimed in claim 1 or claim 2, wherein the secondary air system and the air filter are positioned on the opposite sides of an intake port on the upper surface of the cooling cowl.

4. The mounting structure for a secondary air injection system as claimed in claim 1 or claim 2, wherein the said holder and the mounting inserts are made of any material including plastic resin.

5. The secondary air injection system as claimed in any of the preceding claims, wherein the said vehicle is a scooter type motorcycle.

6. The mounting structure for a secondary air injection system substantially as herein described and illustrated by the accompanying drawings.