DE19808500A1 - Secondary air supply device for exhaust system of motor scooter - Google Patents

Abstract

The secondary air supply device includes an air filter (35) fitted to the silencer (28). The outer end of the secondary air supply tube is connected to the air filter to supply secondary air to the exhaust system. This tube includes a no-return valve (36) in its middle sector. The no-return valve is also fitted to the silencer. Alternatively, the air filter may be at the side, against the transmission casing (22), or may be made in one with the air filter for the intake system, with a common air cleaning chamber for both filters.

Description

The invention relates to a device for supplying secondary air an exhaust system of an internal combustion engine to run in a small Motorcycle, such as a scooter, to clean the exhaust gas.

As a secondary air supply device for a small motorcycle, such as one Scooter or the like, a system is known in which an air filter (a Air filter for the exhaust system) for cleaning the exhaust system secondary air to be supplied is attached to a vehicle main frame and further includes a check valve (a leaf valve) connected to the Internal combustion engine is fixed (Japanese Patent Laid-Open No. Hei-5-139364, 5-131969 and 5-332132). Another system is known in which an air filter for the exhaust system and a check valve til are attached to a storage box under a seat (japani Hei 4-47114).

With the conventional secondary air supply devices, either a part of a secondary air supply pipe, one on the vehicle frame attached air filter for the exhaust system with one on the combustion motor-attached check valve connects, or another secondary Air supply pipe for connecting the attached to the storage box air filter for the exhaust system and the check valve with the Exhaust system (connecting part of the secondary air supply pipe) with one certain lots (bent part) that are formed by Vibration of the internal combustion engine unit caused stretching or Shrinking movements could be absorbed. If beyond that Maintenance work on the secondary air supply device, such as the  Air filter for the exhaust system or the check valve the hull cover had to be removed and fastened.

If the air filter for the exhaust system either on the main frame or the storage box is attached, the air filter is often in a space between the vehicle main frame, the storage box and the fuselage cover attached, and in this case the choice is yours the shape and volume of the air filter for the exhaust system limits. If, for example, the air filter for the exhaust system has a shape with many flat layers under the above restrictions, the planes were vibrated and made noise.

The invention relates to an improvement in the secondary air supply device for the exhaust system of a small motorcycle to solve the above problems. The invention defined in claim 1 is one Secondary air supply device for the exhaust system of a small Motorcycles, secondary air being the exhaust system of the small motorcycle is fed through a secondary air supply pipe, the outer end of which the air filter for the exhaust system is connected and in its between lying part has a check valve, characterized in that the air filter for the exhaust system is arranged on a silencer or is appropriate.

This ensures that the air filter for the exhaust system outside the fuselage cover is arranged so that when attached to the air filter Maintenance work is to be carried out, the fuselage cover is not removed or must be attached. In addition, its shape and Choose volume freely. For example, shape and volume can be so choose that the silencing effect and the effect of silencing of the exhaust gas sound or vibrations of the combustion engine, the transferred from the air filter for the exhaust system, improved can be.  

According to the preferred embodiment of claim 2 it is achieved that the Air filter for the exhaust system and the check valve together with the Mufflers are vibrated, which is part of the swing the internal combustion engine unit, so that you have the secondary air supply pipe as the respective connection between the air filter for the exhaust system, the Check valve and the exhaust system (connecting part of the secondary air Feed pipe) does not have to be shaped so that it vibrates according to the Internal combustion engine can stretch and shrink. So the length each of the sections and the total length of the elements can be shortened.

Because, moreover, the air filter for the exhaust system and the recoil valve are arranged together on the silencer, the entire Secondary air supply device arranged in compact dimensions will. Furthermore, the air filter for the exhaust system and the check valve placed outside the fuselage cover so that it no longer is required when performing maintenance on this Elements to attach or remove the fuselage cover.

Because, moreover, the check valve is far from burning arranged motor, there can be no thermal damage subject to.

After carrying out the invention of claim 3, a secondary air Proposal device for an exhaust system of a small motorcycle gene, whereby secondary air in the exhaust system of the small motorcycle through a Secondary air supply pipe is supplied, the outer end of which with the Air filter for the exhaust system is connected and in between the part has a check valve, characterized in that the Check valve is arranged or attached to a silencer.

This ensures that the check valve outside the fuselage cover is arranged and its maintenance is simplified. Because about it  the check valve swings together with the silencer, which is part of the oscillating engine unit, it will not that part of the secondary air supply pipe that the Check valve connects to the exhaust system (a connecting part of the Secondary air supply pipe), so that it is stretching and shrinking can absorb movement according to vibrations of the internal combustion engine, which shortens its length. Because also the check valve with Distance from the internal combustion engine, it can not be from thermal damage to the engine.

According to the preferred embodiment of claim 4, the air filter swings for the exhaust system together with the power transmission device that is part of the vibrating engine unit so that it is not that part of the secondary air supply pipe that the Air filter for the exhaust system connects to the check valve, so too shape that their stretching and shrinking motion due to vibration of the Internal combustion engine unit is absorbed. Therefore, it can be lengthwise be performed briefly, and furthermore the total length of the secondary air Feed tube are made short.

According to the preferred embodiment of claim 5, the air filter Shape slightly for the exhaust system. Because, moreover, a single Air filter housing or a fastening web or the like is not required, the number of components can be reduced.

Because also the air filter for exhaust system also together with the air filter for the intake system that swings part of the swinging combustion motor unit, you need that part of the secondary air Inlet pipe that contains the air filter for the exhaust system with the check valve connects, do not shape so that its stretching or shrinking is absorbed due to vibrations of the internal combustion engine unit.  

Therefore, it can be made short in length, and further, that Total length of the secondary air supply pipe should be short.

According to the preferred embodiment of claim 6, wherein the outer end of the secondary air supply pipe only through the housing of the air filter for the inlet system runs through and is connected to it the receipt of purified secondary air for the exhaust system, so that the Training of the air filter for the exhaust system is further facilitated.

According to the preferred embodiment of claim 7, a mutual Malfunction between the supply system for the supply to the exhaust system de Secondary air and the supply system for the intake air system primary air to be supplied prevented.

According to the preferred embodiment of claim 8, the respective air inlet passages between the exhaust air filter system and the air filter for the intake air system easily.

According to the preferred embodiment of claim 9, a mutual Malfunction between the secondary air supply system, the exhaust gas system and the primary air supply system that the Inlet gas system supply is even better avoided.

According to the preferred embodiment of claim 10, it is possible to Air filter for the exhaust system on the vehicle frame in a stable manner fasten, and at the same time it is possible to change the external appearance of the Keep silencer and air filter for the intake system.

According to the preferred embodiment of claim 11, the air filter swings for the exhaust system together with the internal combustion engine, so that one the part of the secondary air supply pipe that the air filter for the Exhaust system connects to the check valve, does not have to shape so  that a stretching and shrinking of the same due to vibration of the Internal combustion engine is absorbed. This allows it to be of length briefly, and furthermore the total length of the secondary air can increase guide tube are briefly executed.

In addition, it is possible that the air filter for the exhaust system on the Shield the internal combustion engine in the same place where the main body by the muffler is present, is arranged, whereby the Air filter for the exhaust system and the check valve close to each other can be arranged so that the entire secondary air Can arrange feed device compact.

According to the preferred embodiment of claim 12, the air filter Shape slightly for the exhaust system. Beyond that you don't need one single air filter housing or a fastening web or the like., whereby the number of components can be reduced.

According to the embodiment of claim 13 according to the invention, a Secondary air supply device for an exhaust system of a small motorcycle proposed, in the secondary air the exhaust system of the small Motorcycles are fed through a secondary air supply pipe, the outer End connected to the air filter for the exhaust system and in its intermediate part has a check valve, characterized net that both the air filter for the exhaust system and the rear check valve are arranged under a bottom portion.

This ensures that the air filter for the exhaust system and Check valve together near the combustion link arranged motor, whereby the length of the secondary air Feed pipe can be run short and at the same time the entire Secondary air supply device can be made compact.  

According to the preferred embodiment of claim 14, the length of the Make the secondary air supply pipe shorter.

According to the preferred embodiment of claim 15, the Maintenance work for the main body of the muffler, which on Main body of the muffler arranged secondary air supply device device (the air filter for the exhaust system and the check valve) and that Carry out rear wheel or the like more easily.

According to the preferred embodiment of claim 16, the fastening can or remove the muffler or the secondary air supply device tion (the air filter for the exhaust system, the check valve), which on the Mufflers or located under the bottom section, easily carry out. Furthermore, since these parts are not completely from the vehicle Maintenance work on these items can be removed as well as easier for the rear wheel. Furthermore, that The weight of the vehicle can be made lighter.

According to the preferred embodiment of claim 17, the exhaust gas fully ignite the two-stroke internal combustion engine, clean sufficiently and lead away.

According to the preferred embodiment of claim 18, it is possible that a Muffling effect against exhaust noise from the combustion engine or Vibrating noises of the check valve that hit the air filter for the Exhaust system are transmitted, is improved.

The invention will now be described with reference to exemplary embodiments explained on the accompanying drawings. Show it:  

Fig. 1 in side view of a small motorcycle with a secondary air supply device for an exhaust system according to a preferred embodiment (embodiment 1) according to claims 1 to 3 and 15 to 18th

Fig. 2 is a partially sectioned side view of an essential part of Fig. 1 on an enlarged scale;

Fig. 3 is a partially sectioned schematic plan view of a wesentli Chen part of Figure 1 (internal combustion engine unit) on an enlarged scale.

Fig. 4 is a partially longitudinally sectioned side view of the silencer part in Fig. 2;

Fig. 5 partially in cross section a schematic plan view of the combustion engine unit with the secondary air supply device for the exhaust system according to a preferred embodiment (embodiment 2) according to claim 4, which figure corresponds to Fig. 3;

. Fig. 6 is a schematic plan view of the engine unit to the secondary air supply device for the exhaust system after a Favor th embodiment (Embodiment 3) Figures 5 and 6, this figure corresponds to the demands of Figure 3;

FIG. 7 is a plan view in cross section of a housing part of the air filter in FIG. 6;

Fig. 8 is a schematic plan view of the engine unit to the secondary air supply device for the exhaust system after a Favor th embodiment (embodiment 4) according to claims 7 and 8, this figure corresponds to FIG. 3;

FIG. 9 is a plan view in cross section of a housing part of the air filter in FIG. 8;

FIG. 10 is a plan view in cross section of a housing part in claim 9, this figure corresponds to an air filter in a secondary air supply device for the exhaust system according to a preferred embodiment (embodiment 5) of FIG. 9;

Fig. 11 is a side view of a small motorcycle with the Sekundärluftzu driving device for the exhaust system according to a preferred embodiment (embodiment 6) according to claim 10;

Figure 12 is a schematic plan view of part of the internal combustion engine unit with the secondary air supply device for the exhaust system according to a preferred embodiment (embodiment 7) according to claim 11;

Fig. 13 is a side view of an essential part, seen from the direction XIII in Fig. 12, with a part cut away;

Fig. 14 is a side view of an essential part of the secondary air supply device for the exhaust system according to a preferred embodiment (embodiment 8) according to claim 12, with a part cut away and this figure corresponds to Fig. 13;

15 is a side view of a small motorcycle with the secondary air supply device for the exhaust system according to a preferred embodiment (embodiment 9) according to claims 13 and 14.

FIG. 16 is a schematic plan view, partly in cross section, an essential part of FIG. 15 being enlarged and this figure corresponding to FIG. 3; and

FIG. 17 shows an example of a modification of the embodiment shown in FIG. 15 (embodiment 9).

First, a preferred embodiment (embodiment 1) will be described, which is shown in FIGS. 1 to 4.

In these figures, 1 denotes a motorcycle-type motorcycle for use in a secondary air supply device in an exhaust system of a preferred embodiment 1 shown in the left side view, and 2 denotes a seat in front of which a handlebar head 10 protrudes upward and a lower floor portion 3 spaced from a front part of the seat is arranged.

A handlebar shaft 6 to be rotated by a handle 5 is pivotably mounted on a head tube 7 . A front wheel 9 is suspended from the lower end of the shaft 6 by a front fork 8 . A front frame 10 extends from the head pipe 7 , branches at its lower portion into a right side and a left side extending rearward at the bottom portion 3 , and then the front frame is connected to a rear frame 11 . The rear frame 11 extends obliquely upwards and backwards and reaches the lower part of the rear end of the seat 2 .

The front portion of the vehicle fuselage, the frame of which is formed by this front frame 10 and the rear frame 11 , is provided with a leg guard 12 which covers the rear portion of the front frame 10 and extends along the rear portion thereof, the leg shield 12 in the rearward and rearward direction runs downwards and is connected to a floor cover 13 , which covers a central floor section of the vehicle body. Then the bottom cover 13 is connected to a fuselage cover 14 which covers the rearward portion of the rear frame 11 where it rises from its horizontal portion to the sloping rear portion. The body cover 14 is connected at its front upper portion with a center cover 15 and the center cover 15 is covered, together with the front seat 2, the front portion of a fuel tank 16, which is hidden under the seat. 2

Denoted at 17 is an internal combustion engine unit (swing unit) for suspending a rear wheel 21 , the front portion of which is attached to the front lower portion of the rear frame 11 by a suspension member 18 such that it is pivotable in the upward and downward directions, and the rear portion thereof is on rear portion of the rear frame 11 suspended by a damper unit 19 .

An internal combustion engine 20 is integrally arranged on the front section of the internal combustion engine unit 17 , and a rear wheel 21 is rotatably mounted on the rear section thereof. A power transmission device (continuously variable belt transmission) 22 for transmitting the power of the engine 20 to the rear wheel 21 and a silencer 28 , which is an element constituting the exhaust system to be described later, are integrally arranged on the engine unit 17 with the rear wheel 21 held between them .

The internal combustion engine 20 is a two-stroke internal combustion engine, the intake system of which has an air filter 23 , a carburetor 24 and an intake pipe 25 , which is connected to an intake passage (not shown) of the internal combustion engine 20 .

The exhaust pipe 27 extends from an exhaust passage 26 , which is arranged on a cylinder portion of the internal combustion engine 20 , in the forward and downward direction, is then curved and points in the rearward direction. A main body 30 of the muffler is cooperatively connected to this rear part, and the muffler 28 is constructed from these elements.

The outlet pipe 27 and the main body 30 of the muffler are detachably connected to one another at a connecting part 31 such that respective flanges of these two parts are detachably connected to one another by coupling means, such as bolts and nuts.

As shown in Fig. 2, inside the main body 30 of the muffler is a catalytic converter 32 in the form of a metallic catalyst, and exhaust gas supplied from the exhaust pipe 27 performs an oxidation reaction in the catalytic converter 32 to completely burn the exhaust gas, and that Exhaust gas is released into the surrounding atmosphere in a cleaned state.

Additional secondary air is supplied to the exhaust system mentioned at the outset, as a result of which the exhaust gas cleaning effect of the aforementioned catalytic converter 32 can be improved. This secondary air is supplied from a secondary air inlet passage 34 which is formed relatively close to a portion which is connected to the outlet passage 26 of the combustion engine 20 by a later to be described of the secondary air supply system.

This secondary air supply system comprises an air filter 35 for the exhaust system, a check valve in the form of a leaf valve 36 and a secondary air supply pipe 37 which connects these elements and also connects them to the aforementioned secondary air supply inlet 34 . The secondary air supply pipe 37 includes a flexible rubber hose 38 that connects the air filter 35 for the exhaust system to the leaf valve 36 , a flexible rubber hose 39 on the side of the leaf valve 36 that connects the leaf valve 36 to the secondary air supply inlet 34 , and a Metal pipe 40 at the secondary air supply inlet 34 .

The rubber hose 38 can be separated at connecting sections 37 a, 37 b, and furthermore the hose is detachably connected to the leaf valve 36 at a connecting part 37 d. The rubber hose 39 is also detachably connected with respect to the reed valve 36 on the connecting part 37 e to the reed valve 36th In addition, the rubber hose 39 and the metal tube 40 are releasably connected to a connecting part 37 c, which is located approximately in the middle between the leaf valve 36 and the secondary air supply inlet passage 34 .

The air filter 35 for the exhaust system is fixed to the rear portion of a cock-comb-like vertical fastening piece 41 (see FIG. 4) which is fastened vertically to the upper end of the main body 30 of the silencer, the air intake inlet 35 a of which is fastened in the forward and downward direction by fastening means 42 is composed of bolts and nuts. One side of a clean chamber 35 b inside the air cleaner chamber c by a partition plate 35 divided into two chambers, said two chambers by a tubular connection 35 d are connected to each other. Air cleaned by a filter 35 e passes through these two chambers and emerges from an outlet passage 35 f and is guided to the rubber hose 38 of the secondary air supply pipe 37 .

The reed valve 36 is front by connecting means 44, such as bolts and nuts, at two and rear arms 43 a, b secured 43, which protrude in the horizontal direction from the attachment piece 43 which is fixed to a front wide portion of the vertical mounting piece 41st

This air filter 35 for the exhaust system and the leaf valve 36 are thermally shielded by a muffler cover 45 in front of the main body 30 of the muffler. The muffler cover 45 is attached to the main body 30 of the muffler at a predetermined distance, with a slot part 45 a in the cover portion of the same being placed on a welding web 41 a of the vertical fastening piece 41 .

In this construction of preferred embodiment 1, since both the air filter 35 and the leaf valve 36 for the exhaust system are arranged outside the fuselage cover 14 , it is not necessary, for example for maintenance purposes, to remove and attach the fuselage cover 14 .

In addition, it is possible to freely design both the shape and volume of the air filter for the exhaust system. The exhaust noise of the internal combustion engine, which is transmitted to the air filter 35 for the exhaust system, or the vibration noise of the leaf valve 36 can be damped particularly effectively by making its shape cylindrical or increasing its volume or the clean chamber 35 b in the chamber into a plurality divided by chambers connected in series.

In addition, both the air filter 35 and the leaf valve 36 for the exhaust system swing together with the swinging main body 30 of the muffler of a part of the engine unit 17 , so that it is not necessary to have respective portions 38 , 39 , 40 of the secondary air supply pipe 37 which the Air filter 35 , the leaf valve 36 for the exhaust system and the secondary air supply passage 34 connect to form so that stretching or shrinkage due to vibration of the engine unit 17 can be absorbed, and so that a length of the respective sections 38 , 39 and 40 a total length this can be kept short.

Furthermore, because both the air filter 35 and the blade valve 36 for the exhaust system are all arranged together on the main body 30 of the muffler, the entire secondary air supply device can be arranged in a compact manner.

In addition, because the leaf valve 36 is spaced from the internal combustion engine 20 , there is no possibility that it will be thermally damaged by the engine.

If the main body 30 of the muffler, the secondary air supply device (the air filter 35 for the exhaust system and the leaf valve 36 ) disposed on the main body 30 of the muffler, and the rear wheel 31 or the like are to be repaired and serviced, the Main body 30 of the silencer is removed together with the secondary air supply device. Furthermore, the rear wheel 21 can be removed so that the work can be carried out easily because the main body 30 of the muffler is formed such that it can be freely attached or removed together with the exhaust pipe 27 .

Because in this case the rubber hose 39 is removably arranged on the connecting part 37 c with respect to the metal pipe 40 , the rubber hose 39 is detachable from the metal pipe 40 or the connection state on the connecting part 37 e is detachable to remove the rubber hose 39 from the leaf valve 36 to be able to. Here, the main body 30 of the muffler and the secondary air supply device arranged on the main body 30 of the muffler can be completely separated from the vehicle. This arrangement makes maintenance work even easier.

Because the rubber hose 39 is flexible, the maintenance work can be easily performed even when the main body 30 of the muffler and the secondary air supply device arranged on the main body 30 of the muffler are not completely separated from each other, as described above.

In addition, because the metallic catalyst is housed in the main body 30 of the muffler, a complete combustion of exhaust gas enriched with not yet ignited substances, which is output from the two-stroke engine 20 , can be achieved by the metallic catalyst and the secondary air supplied to the exhaust system, to achieve a sufficient cleaning effect of the exhaust gas and its exhaust process.

Another preferred embodiment (embodiment 2) will now be described with reference to FIG. 5.

In embodiment 2, the air filter 35 for the exhaust system in the secondary air supply device on the housing of a power transmission device (continuously variable belt transmission) 22 via the air filter 23 for the intake system is fastened and arranged by connecting means such as bolts and nuts, not shown . Since the other configurations are similar to that of the embodiment 1, their detailed description is omitted.

Due to this construction of the embodiment 2, the air filter 35 for the exhaust system can swing in this case together with the power transmission device 22 which is part of the oscillating combustion engine unit 17 . Accordingly, you do not need to train that part 38 (rubber hose) of the secondary air supply pipe for connecting the air filter 35 to the leaf valve 36 for the exhaust system in such a way that its stretching and shrinkage due to vibration of the combustion engine unit 17 can be absorbed. Furthermore, its length can be shortened, and moreover, the total length of the secondary air supply pipe 37 can be shortened.

A preferred embodiment (embodiment 3) will now be described with reference to FIGS. 6 and 7.

In embodiment 3, the air filter 35 for the exhaust system in the secondary air supply device is formed integrally with the air filter 23 for the intake gas system, namely by sharing an air cleaning chamber 23 a. Since the other configurations are similar to those of the embodiment 1 , their detailed description is omitted. In addition, 23 e denotes an air intake passage.

Due to this construction of the preferred embodiment 3, it is sufficient to pass only the outer end of the secondary air supply pipe section (rubber hose) 38 through the inner housing 23 b of the air filter 23 for the intake gas system and to connect it. This provides purified secondary air for the exhaust system, so that the design of the air filter 35 for the exhaust system becomes fairly simple. A separate air filter housing or a fastening web or the like is not required, and the number of components can be reduced. In addition, 23 c denotes an outer housing for the air filter of the intake system.

In this case too, the air filter 35 for the exhaust system can oscillate back and forth together with the air filter 23 for the intake system, which is part of the oscillating internal combustion engine unit 17 . Accordingly, a secondary air supply pipe part (rubber hose) 38 for connecting the air filter 35 for the exhaust system to the leaf valve 36 need not be designed such that its stretching or shrinking due to vibration of the engine unit 17 can be absorbed. Furthermore, the length can be shortened and, moreover, the total length of the secondary air supply pipe 37 can be shortened.

A preferred embodiment (embodiment 4) will now be described with reference to FIGS. 8 and 9.

In the preferred embodiment 4, which differs from the embodiment 3, the air filter 35 for the inlet system in the secondary air supply device is integrally formed with the air filter 23 for the inlet system, the respective air cleaning chambers 35 g, 23 d being separated from one another . Here, these air cleaning chambers 35 g, 23 d have a common air intake 23 e. 23 f denotes a partition for separating these two air cleaning chambers 35 g, 23 d. 23 g denotes a filter which is arranged over both air cleaning chambers 35 g, 23 d. The other configurations are similar to that of the embodiment 3, and their detailed description is omitted.

The above construction of the embodiment 4 prevents mutual interference between a system for supplying secondary air to the exhaust system for purifying the exhaust gas of the engine 20 and a system for supplying primary air to the intake system as combustion air for the engine 20 .

In addition, the respective air intake passages between the air filter 35 for the exhaust system and the air filter 23 for the intake system can be easily formed.

A preferred embodiment (embodiment 5) will now be described with reference to FIG. 10.

In the embodiment 5, which differs from the embodiment 4, the two air cleaning chambers 35 g and 23 d have separate air inlet passages 35 h and 23 h. Therefore, both air cleaning chambers 35 g, 23 d are completely separated from each other by a partition 23 i, which is arranged vertically on a common inner housing 23 b, and a partition 23 j, which is arranged vertically on a common outer housing 23 c.

In addition, a filter 35 i for the air filter 35 for the exhaust system and a filter 23 k for the air filter 23 for the intake system are arranged separately, and their inner ends are held and supported by grooves on the outer end of the partition 23 i according to the figure in opposite directions are formed. Because the other configurations are similar to those of the embodiment 4, their detailed description is omitted.

Due to the above construction of the embodiment 5, a mutual Malfunction between the secondary air supply system and the primary air supply system further prevented.

A preferred embodiment (embodiment 6) will now be described with reference to FIG. 11.

In embodiment 6, which differs from embodiments 1 to 5, the air filter 35 for the exhaust system in the secondary air supply device is connected to the rear frame 11 by connecting means 46 , such as bolts and nuts or the like, in such a way that the air filter can be arranged in a free space between the shield 47 for the internal combustion engine 20 and the fuselage cover 14 . Here, the air filter 35 for the exhaust system and the leaf valve 36 are connected by the secondary air supply pipe section (rubber hose) 38 . Because the other configurations are similar to that of the embodiment 1, their detailed description is omitted.

Due to the above construction of the embodiment 6, the air filter 35 for the exhaust system can be fixed to the rear frame 11 in a stable manner. In addition, the external appearance of the main body 30 of the muffler and the air filter 35 for the intake system is not affected.

A preferred embodiment (embodiment 7) will now be described with reference to FIGS. 12 and 13.

In embodiment 7, which differs from embodiments 1 to 6, the air filter 35 for the exhaust system in the secondary air supply device is attached to the right side surface of the shield 47 of the internal combustion engine 20 by connecting means 48 using a bolt and a nut and arranged. Because the other configurations are similar to those of the embodiment 1, their detailed description is omitted.

Furthermore, the shield 47 covers the cylinder part of the internal combustion engine 20 , and the ambient air is sucked by a blower from a cold air inlet passage formed on either the front surface or the left side surface, and flows into the shield 47 to the cylinder part (not shown) forced to cool.

Due to the above construction of the embodiment 7, the air filter 35 for the exhaust system can vibrate together with the internal combustion engine 20. Therefore, it is not necessary to form the secondary air supply pipe section (rubber hose) 38 for connecting the air filter 35 of the exhaust system with the leaf valve 36 so that stretching or shrinking thereof due to vibrations of the engine 17 can be absorbed. Therefore, the length thereof can be made short and also an entire length of the secondary air supply pipe 37 can be made short.

Further, since the air filter 35 for the exhaust system is disposed on the right side surface of the shield 47 on the same side as that of the main body 30 of the muffler, the air filter 35 for the exhaust system and the leaf valve 36 can be arranged approximately, and further, the whole Secondary air supply device can be arranged in a compact size.

A preferred embodiment (embodiment 8) will now be described with reference to FIG. 14.

In embodiment 8, which differs from embodiment 7, the air filter 35 for the exhaust system in the secondary air supply device is integrally formed and arranged on the outer wall of the shield 47 of the internal combustion engine 20 .

Here, an inner housing 35 j of the air filter 35 for the exhaust system is formed integrally with the housing of the shield 47 of the internal combustion engine 20 . The outer housing 35 is molded separately to facilitate mounting and maintenance of the filter 35 l. Because other configurations are similar to that of Embodiment 7, their detailed description is omitted.

Due to the above construction of the embodiment 8, the shaping of the air filter 35 for the exhaust system is facilitated. In addition, because it is not necessary to prepare a separate air filter or a mounting bracket or the like, the number of components can be reduced.

A preferred embodiment (embodiment 9) will now be described with reference to FIGS. 14 to 17.

In embodiment 9, which differs from embodiments 1 to 8, the air filter 35 for the exhaust system and the leaf valve 36 in the secondary air supply device are fastened in a horizontally extending part of a front frame 10 under the floor 3 by connecting means (not shown) and arranged using a web that protrudes from the front frame 10 , a bolt and a nut.

Here is the secondary air supply pipe 37 for connecting the air filter 35 for the exhaust system and the leaf valve 36 with the secondary air inlet passage 34 , which is formed on the outlet pipe 27 of the engine 20 (see Fig. 16), so that it is arranged by a Passes near the suspension ring or member 18 for the engine unit 17 .

FIGS. 15 and 16 show a state in which the device is applied to a small motorcycle, which is provided with a vertical internal combustion engine 20 which is inclined at an angle from the vertical from the rear. Fig. 17 shows another state in which the device is applied to a small motorcycle which is provided with a horizontal internal combustion engine 20 which stands up a little from its horizontal.

If, in embodiment 9, maintenance work for the air filter 35 for the exhaust system or the leaf valve 36 has to be carried out, an under cover 50 (FIGS . 15, 17) is removed from the vehicle.

Due to the above construction of the embodiment 9, it is possible that the air filter 35 for the exhaust system and the leaf valve 36 are arranged together near the suspension member 18 of the engine unit 17 , whereby the length of the secondary air supply pipe 37 can be shortened. In addition, the entire secondary air supply device can be arranged compactly.

An air filter 35 of a secondary air supply device for the exhaust system of a small motorcycle is arranged on the muffler 28 . An outer end of a secondary air supply pipe is connected to the air filter 35 to supply secondary air to the exhaust system of the small motorcycle 1 through the secondary air supply pipe 37 , in the intermediate part of which a check valve 36 is arranged. The check valve 36 is also provided on the muffler 28 . This eliminates the need to attach or remove a cover for maintenance work on the secondary air supply device for the exhaust system of the small motorcycle, increases the design freedom of the air filter, improves the noise reduction effect and also shortens the length of the secondary air supply pipe.

Claims (18)

1. secondary air supply device for an exhaust system of a small motorcycle ( 1 ), wherein secondary air is supplied to the exhaust system of the small motorcycle ( 1 ) through a secondary air supply pipe ( 37 ), the outer end of which is connected to the air filter ( 35 ) for the exhaust system and which in its intermediate part has a check valve ( 36 ), characterized in that the air filter ( 35 ) for the exhaust system is arranged on a silencer ( 28 ). 2. Secondary air supply device according to claim 1, characterized in that the check valve ( 36 ) is also attached to the silencer ( 28 ). 3. Secondary air supply device for an exhaust system of a small motorcycle ( 1 ), wherein secondary air is supplied to the exhaust system of the small motorcycle ( 1 ) through a secondary air supply pipe ( 37 ), the outer end of which is connected to the air filter ( 35 ) for the exhaust system and which has in its intermediate part a check valve ( 36 ), characterized in that the check valve ( 36 ) is arranged on a silencer ( 28 ). 4. Secondary air supply device according to claim 3, characterized in that the air filter ( 35 ) for the exhaust system is arranged laterally next to a housing of a power transmission device ( 22 ) over the air filter ( 23 ) for an intake gas system. 5. Secondary air supply device according to claim 3, characterized in that the air filter ( 35 ) for the exhaust system is integrally formed with the air filter ( 23 ) for the intake system. 6. Secondary air supply device according to claim 5, characterized in that the air filter ( 35 ) for the exhaust system is integrally formed with the air filter ( 23 ) for the intake system, which cooperate with a single air cleaning chamber ( 35 g). 7. Secondary air supply device according to claim 5, characterized in that the air filter ( 35 ) for the exhaust system is integrally formed with the air filter ( 23 ) for the inlet system, with respective air cleaning chambers ( 35 g, 23 d) being separated from one another. 8. Secondary air supply device according to claim 7, characterized in that the respective air cleaning chambers ( 35 g, 23 d) have a common air inlet passage ( 23 e). 9. Secondary air supply device according to claim 7, characterized in that the respective air cleaning chambers ( 35 g, 23 d) have separate air inlet passages ( 35 h, 23 h). 10. Secondary air supply device according to claim 3, characterized in that the air filter ( 35 ) for the exhaust system on the rear frame ( 11 ) of the vehicle is arranged. 11. Secondary air supply device according to claim 3, characterized in that the air filter ( 35 ) for the exhaust system on a shield ( 47 ) of an internal combustion engine ( 20 ) of the vehicle is arranged. 12. Secondary air supply device according to claim 11, characterized in that the air filter ( 35 ) for the exhaust system is integrally formed with a shield ( 47 ) of the internal combustion engine. 13. Secondary air supply device for an exhaust system of a small motorcycle ( 1 ), wherein secondary air is supplied to the exhaust system of the small motorcycle ( 1 ) through a secondary air supply pipe ( 37 ), the outer end of which is connected to the air filter ( 35 ) for the exhaust system and which in its intermediate part has a check valve ( 36 ), characterized in that both the air filter ( 35 ) for the exhaust system and the check valve ( 36 ) are arranged under a bottom portion ( 3 ). 14. Secondary air supply device according to claim 13, characterized in that the secondary air supply pipe ( 37 ) passes through a location near the suspension member ( 8 ) of the engine unit ( 17 ) of the vehicle. 15. Secondary air supply device according to one of claims 1 to 14, characterized in that the muffler ( 28 ) comprises a main body ( 30 ) of the muffler ( 28 ) and the exhaust pipe ( 27 ), this main body ( 30 ) of the muffler ( 28 ) and the exhaust pipe ( 27 ) are designed to be separable from one another. 16. Secondary air supply device according to one of claims 1 to 15, characterized in that the secondary air supply pipe ( 37 ) which extends from the check valve ( 36 ) to the exhaust system ( 27 ) has a flexible hose ( 39 ) which Check valve ( 36 ) connects to a metal pipe ( 40 ) on the exhaust system ( 27 ). 17. Secondary air supply device according to one of claims 1 to 16, characterized in that the internal combustion engine ( 20 ) is a two-stroke internal combustion engine and in the silencer ( 30 ) a catalyst ( 32 ) is housed. 18. Secondary air supply device according to one of claims 1 to 17, characterized in that in a chamber of the air filter ( 35 ) for the exhaust system a clean chamber side ( 35 b) is formed, the chamber being divided into a plurality of serially connected chambers .