DESC:FIELD OF INVENTION

The invention relates generally to an exhaust gas purifying system for an internal combustion engine and, in particular, to position of a secondary air injection valve of the exhaust gas purifying system in saddle type vehicles.

BACKGROUND

With growing concern of increased pollution, global warming etc., and depletion of natural resources, it is essential to reduce automotive emissions and use of the fuel to the optimum level. Usually automotive emissions are specified in terms of amount of hydrocarbon (HC) and carbon monoxide (CO) in the exhaust gas.

One of the common practice, to reduce concentrations of HC and CO in exhaust gas from an internal combustion engine, is to provide an exhaust gas purifier of the type that oxidizes exhaust gases using secondary air provided through a secondary air injection system. To optimize the amount of secondary air mixed with the exhaust gas, a secondary air control device is provided to control pressure, within a secondary air supply pipe, which is delivered from an air pump. In some cases, air injection can also be achieved by taking advantage of the negative pressure pulses in the intake manifold. The secondary air which is mixed with the exhaust gas is usually drawn from the primary air cleaner of the vehicle. However, a separate secondary air cleaner may be provided based on design and packaging requirements.

Use of an exhaust gas purifying system using secondary air injection is common in Saddle type vehicle to reduce the pollutant level in exhaust gas. Saddle type vehicle, being a compact vehicle, packaging of additional components such as secondary air control device, secondary air cleaner, associated tubing, etc. is always a challenge.

Saddle type vehicles such as motorcycle, scooter, use various type frame structures for mounting of various vehicle components such as engine, fuel tank, air cleaner, etc. One such frame structure used in motorcycle is a perimeter type frame which has two side members extending rearward from the head pipe creating a space there between within which engine and other vehicle components are usually accommodated.

In a saddle type vehicle with a perimeter type frame, as the engine, elements of intake system, etc. are positioned within the side members of the frame, hence positioning of the secondary air control device and associated tubing becomes challenging. The secondary air control device may be positioned within the side members of the perimeter frame above engine as described in JP04755513B2. However, this exposes the secondary air control device and associated tubing to direct engine heat which may deteriorate its performance. Further, if the engine height is more, such position may not be feasible at all as engine head may foul with positioning of secondary air control device.

Such position may also pose challenge in mounting of the fuel tank which is usually mounted over side members extending rearward from the head pipe. Further, positioning of the secondary air control device may create challenge during servicing of the engine by obstructing the access to engine from top.

Alternately, the secondary air control device may be mounted on rear side of the frame for e.g. seat support frame. However, this will lead to increase in tubing length associated with the secondary air system. This also increases material required, cost and complexity in assembly and maintenance. Increased tubing length also increases the pressure drop which may affect the functionality and performance of the secondary air control device. Mounting of the secondary air control device on rear side of the frame also exposes it to customer view and deteriorates the aesthetic appeal of the vehicle.

Due to the unique structure of the perimeter frame, limited space is available along the width of the frame. Accommodating additional component such as secondary air control device within vehicle width between the side members of the perimeter frame is difficult.

In light of foregoing discussion, there is a need to provide a secondary air injection system for saddle type vehicle with a perimeter frame to overcome the limitations stated above.

OBJECTIVES OF THE INVENTION

It is an object of the present invention is to provide an improved secondary air injection system wherein the secondary air control device has optimum tubing length.

Yet another object of the present invention is to provide a secondary air injection system with a secondary air control device which is protected from exposure to dust, dirt and water.

It is an object of the present invention is to provide an improved secondary air injection system wherein the secondary air control device is protected from the direct engine heat.

Yet another object of the present invention is to provide a secondary air injection system with a secondary air control device which is easy to assemble, easy to service and cost effective.

Yet another object of the present invention is to provide a secondary air injection system with a secondary air control device which is accommodated within the vehicle width without affecting position of other components.

Yet another object of the present invention is to provide a secondary air injection system which does not affect the vehicle aesthetics.

SUMMARY OF THE INVENTION

With such objects in view, the present invention provides a saddle type vehicle comprising
a frame having a head pipe, a plurality of side members extending rearward and downward from the head pipe forming a hollow space there between and a seat frame extending rearward from the plurality of side members;
an engine positioned within the hollow space between the plurality of side members; and
an exhaust gas purifying system comprising a secondary air control device to control supply of secondary air within a secondary air supply pipe;
wherein the secondary air control device is mounted on one of side member of the frame.

The plurality of side members of the frame may be classified as a left side member which is positioned on the left side of driving direction and a right side member which is positioned on right side of driving direction. The secondary air control device is preferably mounted on left side member of the frame. Further, the secondary air control device is mounted within the hollow space between the side members.

Further, position of the secondary air control device is such that
- the secondary air control device is at least partially behind an engine cylinder
- the secondary air control device is at least partially between the engine cylinder and an air cleaner
- the secondary air control device is at least partially above a transmission
- the secondary air control device is at least partially between an intake port of the engine and the transmission

The frame used in the saddle type vehicle is a perimeter type frame.

In case of the perimeter frame, various wiring harnesses e.g. wiring harness of the headlights, horn, etc. is routed along the side members of the frame. Further, in some cases the wiring harnesses need to be routed across the side members of the frame for e.g. wiring harness for starter motor. The wiring harness is attached to the side members using attaching members such as clips, hooks, etc. Mounting of the secondary air control device on the side member of the frame causes obstruction in routing of the wiring harness. The attaching members for the wiring harness are suitably repositioned/ reoriented on the side member or within the hollow space between the side members of the frame so as to avoid obstruction to routing of the wiring harness.

When the secondary air control device is mounted on the side member of the frame, carburetor and its choke lies in proximity of the secondary air control device. The secondary air control device is positioned such that it does not obstruct access to the choke and allows the free movement of the choke.

As the secondary air control device is at least partially behind an engine cylinder, it is protected from direct engine heat. This helps to prevent deterioration in performance of the secondary air control device. Further, the positioning of secondary air control device between the engine cylinder and an air cleaner is such that it does not affect volumetric capacity of the air cleaner which may otherwise affect engine performance. Further, the position of air filter need not to be altered which may otherwise lead to change in position and packaging of other associated components.

As the secondary air control device is mounted on the side member of the frame from inside of the frame, it is not directly visible. This eliminates any effect on the vehicle aesthetics due to presence of the secondary air control device. Further, this position also protects the secondary air control device from direct exposure to dust, debris, mud, water, etc. This also prevents any direct mechanical impact on the secondary air control device.

The saddle type vehicle may be provided with a mounting means for mounting the secondary air control device on the side member. Preferably the mounting means is a bracket attached to the side member. Mounting bracket is attached to the side member of the frame such that, it does not obstruct routing of the wiring harness and positioning and working of other vehicle components such as choke, air cleaner, etc. The bracket along with the secondary air control device may be formed as a separate subassembly and mounted on the side member. This provides ease of assembly and facilitates easy maintenance.

In one of the embodiments of the invention, the exhaust gas purifying system may take clean air to be injected in exhaust gas through the secondary air control device from a main air cleaner that supplies air to the engine as well.

In yet another aspect of the invention, a saddle type vehicle comprising
a frame having a head pipe, a plurality of side members extending rearward and downward from the head pipe forming a hollow space there between and a seat frame extending rearward from the plurality of side members;
an engine positioned within the hollow space between the plurality of side members; and
an exhaust gas purifying system comprising a secondary air control device to control supply of secondary air within a secondary air supply pipe and a secondary air cleaner which supplies clean air to the secondary air control device;
wherein the secondary air control device and the secondary air cleaner is mounted on one of side member of the frame.

In yet another aspect of the invention, where the secondary air cleaner is provided for clean air supply to the exhaust gas purifying system, the secondary air cleaner is mounted on same the mounting means i.e. a bracket that is being used for mounting of the secondary air control device on the side member.

Mounting of the secondary air cleaner and the secondary air control device enables accommodation of key components of the exhaust gas purifying system within minimum space. Further, as both components are mounted on same bracket, they are in close proximity. This keeps the tubing length minimum. Also, this arrangement eliminates the need of additional bracket. Due to which cost is reduced and overall assembly becomes compact.

As the secondary air cleaner and the secondary air control device are mounted on the same bracket, it may be formed as a separate subassembly during manufacturing and directly mounted on the side member of the frame. This enhances the ease of assembly and optimizes the production time. Such arrangement also facilitates easy maintenance.

Further, such positioning of the secondary air cleaner along with the secondary air control device does not affect the position, function or performance of other vehicle components such as choke, main air cleaner, wiring harness, etc.

The exhaust gas purification system described above allows improved packaging and performance of the secondary air control device. At the same time, the exhaust gas purification system described herein provides other benefits such as protection of the secondary air control device from dust, dirt, debris and water, preservation of vehicle aesthetics and ease of assembly and maintenance. The proposed position also suits in a vehicle where engine height is more. Further, all the benefits are achieved without affecting position, function or performance of other vehicle components.

BRIEF DESCRIPTION OF DRAWINGS

In the drawings:

Figure 1 is a side view of a motorcycle including the secondary air injection system according to one embodiment of the present invention.

Figure 2A and 2B are orthogonal views of a perimeter frame structure of the motorcycle in figure 1.

Figure 3 is a side view of the frame along with the components accommodated within frame of the motorcycle of the figure 1.

Figure 4 is an orthogonal view of the frame along with arrangement of wiring harnesses

Figure 5A and 5B are orthogonal views of the frame along with the bracket mounted with the secondary air control device.

Figure 5C represent changes made in the positioning of the clip/s for mounting of wiring harnesses according to one embodiment of the invention.

Figure 6A is an orthogonal view of the frame along with the bracket mounted with the secondary air control device and its associated tubing connections.

Figure 6B and 6C are top views of the frame along with the bracket mounted with the secondary air control device and its associated tubing connections.

Figure 7A and 7B are schematic of the secondary air injection system along with secondary air control device and its associated tubing connections with vehicle components.

Figure 7C is a side view depicting position of the secondary air control device relative to other vehicle components.

Figure 7D is side view depicting position of the secondary air control device relative to other vehicle components.

Figure 8A is an orthogonal views of the assembly of the secondary air control device and its supporting bracket.

Figure 8B is an exploded view of the assembly of the secondary air control device and its supporting bracket.

Figure 9 is a cross sectional view of the secondary air control device.

Figure 10 is an orthogonal view of the frame along with the bracket mounted with the secondary air control device and secondary air cleaner.

Figure 11A and 11B are orthogonal views of the assembly of the secondary air control device, the secondary air cleaner and its supporting bracket.

Figure 11C is an exploded view of the assembly of the secondary air control device, the secondary air cleaner and its supporting bracket.

Figure 12A is an orthogonal view of the bracket for mounting of the secondary air control device and the secondary air cleaner

Figure 12B is an side view of the bracket for mounting of the secondary air control device and the secondary air cleaner
DETAILED DESCRIPTION

Description of preferred but non-limiting embodiments of the secondary air injection system of the present invention will now follow with reference to the above drawings.

Referring to Figures 1 to 3, there is shown a motorcycle 100 having a frame 110 and front forks 105. Front wheel 70 is connected to front forks 105 in conventional manner. The frame 110 of the motorcycle 100 comprises a head pipe 115, side member 125L on left of the head pipe 115 in driving direction and side member 125R on right of the head pipe 115 in driving direction extends rearward and diagonally downward from the head pipe 115, and a seat frame 130 that extends rearward from the side members 125L and 125R. The hollow space 135 formed between the side members 125L and 125R of the frame 110 accommodates other vehicle components such as engine, transmission, air cleaner, carburetor, etc. The side members 125L and 125R may be connected to each other using cross bars 127 at one or more locations which imparts strength and stiffness to overall frame 110.

A fuel tank 60 is mounted behind the head pipe 110 within the space formed by the frame side members 125L and 125R. The fuel tank 60 may be provided with suitable cowl 65 for aesthetic and aerodynamic purposes. A seat 90 is mounted on the seat frame 130 in a conventional manner. An engine 50 along with the transmission 160 is positioned between the side members 125L and 125R of the frame 110 and suitably supported on the frame. Rear wheel 80 is connected to the frame 110 through a swing arm 52. An air cleaner 150 is mounted behind the engine 50 within the space formed between the seat frame members 130 with the help suitable mounting arrangement for e.g. bolting arrangement. A carburetor 152 is positioned between the engine 50 and the air cleaner 150 and above the engine transmission 160. The carburetor 152 is connected to the air cleaner 150 to provide air fuel mixture to an engine intake manifold 51. A sleeve 154 connects the engine intake manifold 51 and the carburetor 152. The sleeve 154 acts as insulation and protects the carburetor 152 from heat of the engine intake manifold 51. The motorcycle 100 is also provided with a muffler 170 connected to the engine 50.

Referring to figure 4, various wiring harnesses such as wiring harness 140 of the headlights, horn, etc. is routed along the side members 125L and 125R of the frame 110. Further, some wiring harnesses need to be routed along and across the side members 125L and 125R of the frame for e.g. wiring harness 142 for a starter motor. The wiring harness 140 is attached to the side members using attaching members such as clips, hooks, etc.

Due to mounting of the various vehicle components such as engine 50, transmission 160, carburetor 152, air cleaner 150, etc. within the side members 125L and 125R of the frame 110, limited space is available for mounting any other additional components. Further as wiring harnesses 140, 142 are routed along and across the side members 125L and 125R, mounting space for any other additional components such as an exhaust gas purifier system is not conveniently available.

An exhaust gas purifier system needs to be provided for reducing concentrations of HC and CO in exhaust gas from the engine 50. In the present invention, an exhaust gas purifier system is provided which oxidizes exhaust gases using secondary air provided through a secondary air injection system. Referring to figure 5A to 7D, in one aspect of the invention, the secondary air injection system includes a secondary air control device 200 and its associated tubing which connects it with the air cleaner 150, the intake manifold 51 and an engine head 49.

In one embodiment of the invention, the secondary air control device 200 is mounted preferably on the side member 125L of the frame. The mounting bracket 190 is provided to mount the secondary air control device 200. The secondary control device 200 is mounted on the mounting bracket 190 and the mounting bracket 190 is in turn mounted on the side member 125L of the frame 110. The mounting bracket 190 may be attached to the side member 125L by various attaching methods for e.g. welding, bolting, etc.

The secondary air control device 200 is preferably positioned on side member 125L such that it is at least partially behind the engine cylinder 48, at least partially between the engine cylinder 48 and an air cleaner 150, at least partially above the engine transmission 160 and at least partially between the intake port 45 of the engine 50 and the transmission 160.

While accommodating the secondary air control device 200, the attaching members for the wiring harness 140 and 142 such as hooks and clips are suitably repositioned/ reoriented on the side member 125L and 125R of the frame 110 so as to avoid obstruction to routing of the wiring harness. One such change is represented in the figure 5C. The clip C’ represents position of clip before mounting of the secondary air control device 200. To facilitate the mounting and positioning of air control device 200, the clip is repositioned from position C’ to position C.

While positioning the secondary air control device 200 on the frame 110, the secondary air control device 200 is attached to the mounting bracket through suitable attaching arrangement such as bolting, gluing, welding, etc. In another aspect of invention, the secondary air control device 200 and the mounting bracket 190 may be formed as integral assembly.

The position of the secondary air control device 200 on the side member 125L of the frame 110 is in proximity of the carburetor 152 and its choke. The secondary air control device 200 is positioned such that it does not obstruct access to the choke and allows the free movement of the choke.

Since the position of the secondary air control device 200 is at least partially behind an engine 50, it is protected from direct engine heat. This helps to prevent deterioration in performance of the secondary air control device 200. As the secondary air control device 200 is not positioned above the engine 50, the proposed position suits in cases where engine height is more. Further, the positioning of secondary air control device 200 between the engine 50 and the air cleaner 150 is such that it does not affect volumetric capacity of the air cleaner which may otherwise affect engine performance. Further, the position of air filter 150 need not to be changed which may have affected position and packaging of other associated components.

Further, as the secondary air control device 200 is mounted on the side member 125L of the frame 110 from inside of the frame, it is not directly visible. This eliminates any effect on the vehicle aesthetics due to presence of the secondary air control device. This protects the secondary air control device from direct exposure to dust, debris, mud, water, etc. This also prevents any direct mechanical impact on the secondary air control device 200.

Referring to Figures 6A to 9, now the schematic of the secondary air injection system and its working are explained. The secondary air control device 200 is in the form of a one way valve which allows the flow of the secondary air only in one direction. In one of the embodiments, the secondary air control device 200 includes a hollow body 205 within which a spring loaded diaphragm 206 is placed to allow one way flow of the secondary air. The secondary air control device has three nozzles namely an air filter connection nozzle 225, an intake manifold nozzle 235 and an exhaust nozzle 215. All the nozzles are in fluid communication with the hollow body 205 of the secondary air control device 200.

The air filter connection nozzle 225 is connected to a clean side of the air cleaner 150 through a tube 220 which carries a clean air from the air cleaner 150 to be injected in exhaust gas of the vehicle. The intake manifold nozzle 235 is connected to the intake manifold 51 of the engine 50 through a tube 230. This connection communicates pressure drop in the intake manifold 51 to the diaphragm 206 in the body 205 of secondary air control device 200 based on which the diaphragm 206 remain opens or close to allow or stop the flow of the secondary air.

The exhaust nozzle 215 of the secondary air control device 200 is connected to the engine head 49 through tube 210. A hole is provided in the engine head such that the secondary air carried by the tube 210 is released at the exit of the exhaust gas in order to oxidize the unburnt fuel residues in the exhaust gas to reduce the amount of pollutant in the exhaust. The tube 210 can be connected to exhaust pipe, however temperature in the exhaust pipe is lower than in engine head. Due to which the oxidation of unburnt fuel may not happen and desired effect of reducing pollutant in the exhaust in may not be achieved.

During the working of the secondary air injection system when the engine 50 is operating at lower rpm for e.g. 1200 rpm, the speed of air in the intake manifold 51 is low and pressure is high. Due to which the diaphragm 206 under pressure from the intake manifold and the tension of spring 207 remains open and secondary air from the air cleaner 150 travel through the secondary air control device 200 in to the engine exhaust. However, when the engine speed increases, the velocity of air in the intake manifold 51 increases and pressure reduces. This lead to pressure drop in the body 205 of the secondary air control device 200 and diaphragm 206 closes and stops the flow of the secondary air.

In one of the embodiments of the invention for mounting of the secondary air control device 200 on the mounting bracket 190, bolting arrangement is provided. The mounting bracket 190 has two holes 191 and the body 205 of secondary air control device 200 is also provide with the matching holes 251 through which bolts 250 pass. For the firm mounting and prevent effect of vibration, the holes 191 of the mounting bracket 190 are provided with rubber grommets 270. Finally assembly is secured with nuts 280 on the other end of the bolts 250.

In an another embodiment of the invention, referring to Figure 10 to 11C, the secondary air to the secondary air control device 200 is provided from the secondary air cleaner 300 instead of the main air cleaner 150. The secondary air cleaner 300 is mounted on the same mounting bracket 190 which is used for the mounting of the secondary air control device 200 using a suitable mounting arrangement for e.g. nuts and bolts. In this case the air filter connection nozzle 225 is connected to a clean side of the secondary air cleaner 300 through a tube 220 which carries a clean air from the secondary air cleaner 300 to be injected in exhaust gas of the vehicle. Rest of the assembly works in the same way as explained earlier for the arrangement with main air cleaner 150. This arrangement also helps in cases where increasing the capacity of main air cleaner is not possible.

For mounting of the secondary air cleaner 300 and secondary air control device 200 on same the mounting bracket 190, certain changes made in the structure of the mounting bracket 190. Referring to Figure 12A and 12B, the modified mounting bracket 190 has two substantially perpendicular faces 193a and 191a. However, the orientation of the faces may be varied based on availability of space, shape of secondary air filter, etc.

First face 193a of the bracket 190 is provided with holes 193 using which the bracket 190 is mounted on the frame side member 125L. The second face 191a is provided with the holes 191 for mounting of the secondary air control device 200. Nuts 250 pass through the holes 191 to mount the secondary air control device 200 on the bracket 190. The second face 191a is also provided with a profile 195 between the holes 191. The profile 195 is such that body 205 of the secondary air control device 200 is accommodated in it. Further, for mounting of the secondary air cleaner 300 on the bracket 190, the second face 191a of the bracket 190 is provided with extensions 192a provided on the outer ends of the second face 191a. The extension extends substantially perpendicular to the second face 191a and parallel to first face 193a. The extensions are provided with holes 192 for facilitating the mounting of secondary air cleaner 300 on the bracket 190 using nuts and bolts.

Provision of secondary air cleaner 300 on the same mounting bracket 190 makes the arrangement more compact. This also reduces the cost and material required. Assembly of the secondary air cleaner 300 and the secondary air control device 200 can be formed as a separate subassembly which can be directly mounted on the frame. This also reduces time and effort involved in the assembly process.

The exhaust gas purifying system described above has number of advantages such as it allows improved packaging and performance of the secondary air control device, protection of the secondary air control device from dust, dirt, debris and water, preservation of vehicle aesthetics and ease of assembly and maintenance. Further, all the benefits are achieved without affecting position, function or performance of other vehicle components.

While various aspects and embodiments have been disclosed herein, modifications and variations to the invention described herein may be apparent to those skilled in the art. Such modifications and variations are deemed within the scope of the present invention. The applicant intends to rely on the provisional specification and drawings annexed to the provisional specification.
,CLAIMS:1. An exhaust gas purifying system for a saddle type vehicle, the saddle type vehicle comprising
a frame having a head pipe, a plurality of side members extending rearward and downward from the head pipe forming a hollow space there between and a seat frame extending rearward from the plurality of side members;
an engine positioned within the hollow space between the plurality of side members; and
the exhaust gas purifying system comprising a secondary air control device to control supply of secondary air;
wherein the secondary air control device is mounted on one of the side member of the frame.

2. The exhaust gas purifying system for the saddle type vehicle according to claim 1 wherein, the secondary air control device is positioned at least partially behind an engine cylinder.

3. The exhaust gas purifying system for the saddle type vehicle according to claim 1 wherein, the secondary air control device is positioned at least partially between the engine cylinder and an air cleaner.

4. The exhaust gas purifying system for the saddle type vehicle according to claim 1 wherein, the secondary air control device is positioned at least partially above a transmission.

5. The exhaust gas purifying system for the saddle type vehicle according to claim 1 wherein, the secondary air control device is positioned at least partially between an intake port of the engine and the transmission.

6. The exhaust gas purifying system for the saddle type vehicle according to claim 1 wherein, the frame of the saddle type vehicle is a perimeter type frame.

7. The exhaust gas purifying system for the saddle type vehicle according to claim 1 wherein, the frame has a left side member positioned on left side of driving direction and a right side member positioned on right side of driving direction and the secondary air control device is mounted on left side member of the frame.

8. The exhaust gas purifying system for the saddle type vehicle according to claim 1 wherein, the secondary air control device is within the hollow space between the side members.

9. The exhaust gas purifying system for the saddle type vehicle according to claim 1 wherein, a mounting means such as a bracket is provided for mounting the secondary air control device on the side member.

10. The exhaust gas purifying system for the saddle type vehicle according to claim 1 wherein, the exhaust gas purifying system take clean air to be injected in exhaust gas through the secondary air control device from a main air cleaner.

11. An exhaust gas purifying system for a saddle type vehicle, the saddle type vehicle comprising
a frame having a head pipe, a plurality of side members extending rearward and downward from the head pipe forming a hollow space there between and a seat frame extending rearward from the plurality of side members;
an engine positioned within the hollow space between the plurality of side members; and
the exhaust gas purifying system comprising a secondary air control device to control supply of secondary air and a secondary air cleaner which supplies clean air to the secondary air control device;
wherein the secondary air control device is mounted on one of the side member of the frame and the secondary air cleaner is mounted on any of the frame member.

12. The exhaust gas purifying system for the saddle type vehicle according to claim 11 wherein, the secondary air control device and the secondary air cleaner is mounted on one of the side member of the frame.

13. The exhaust gas purifying system for the saddle type vehicle according to claim 12 wherein, a common mounting means such as a bracket is provided for mounting the secondary air control device and the secondary air cleaner on the side member.