ITTO980205A1 - SECONDARY AIR SUPPLY DEVICE FOR THE GAS EXHAUST SYSTEM OF A SMALL MOTORCYCLE. - Google Patents

Description

DESCRIPTION of the industrial invention entitled: "SECONDARY AIR SUPPLY DEVICE FOR THE GAS EXHAUST SYSTEM OF A SMALL MOTORCYCLE"

DESCRIPTION

The present invention relates to a device for supplying secondary air to a gas exhaust system of an internal combustion engine for the purpose of purifying the exhaust gases in a small motorcycle, such as a scooter or the like.

As a secondary air supply device for a small motorcycle, such as a conventional scooter or the like, a system is provided in which an air cleaner (air cleaner for a gas exhaust system) for cleaning secondary air fed to the system exhaust gas is fixed to a frame of the vehicle body and also having a shut-off valve (a reed valve) fixed to the internal combustion engine (Japanese patent publications available to the public Nos. Hei 5-139.364, 5- 131.969 and 5-332.132) and another system in which an air cleaner for the exhaust gas system and a shut-off valve are attached to a storage container under a saddle (Japanese patent publication available to the public No. Hei 4 -47.114) or similar.

In the secondary air supply device according to the aforementioned prior art, a secondary air supply duct portion connecting an air cleaner for a gas exhaust system fixed to the vehicle frame with a shut-off valve fixed to the engine at internal combustion or another secondary air supply duct to connect the air cleaner for the gas exhaust system fixed to a storage container and the shut-off valve with the gas exhaust system (connection part of the gas supply duct secondary air) must be made in an elongated shape with the application of a certain flexibility (a bent part) so as to be able to absorb the elongation or shortening produced by oscillations of the internal combustion engine group. In addition, when a maintenance operation was performed for the secondary air supply device, such as the air cleaner for the exhaust gas system or the shut-off valve, attachment or disassembly of the body shell was required.

Also, in case the air cleaner for the exhaust gas system is attached to the body frame or glove box, it is often found that the air cleaner is installed in an empty space between the vehicle body frame, the glove box and the body trim and in this case the definition of the shape and volume of the air cleaner for the exhaust gas system is limited. So, for example, if the air purifier for the gas exhaust system is made to have a shape with many flattened planes when the previous limitation applies, the planes are made to vibrate generating a noise, introducing a disadvantage.

The present invention relates to an improvement of the secondary air supply device for the gas exhaust system of a small motorcycle which solves the aforementioned problems, and the invention described in claim 1 consists of a fuel supply device. secondary air for a small motorcycle exhaust system where secondary air is supplied to the small motorcycle exhaust system through a secondary air supply duct whose end end is connected to the air cleaner for the gas exhaust system and which has an interception valve installed in its central part, characterized in that the aforementioned air purifier for the gas exhaust system is arranged in correspondence with a muffler.

Since the invention described in claim 1 is constructed as described above, the air cleaner for the exhaust gas system is arranged to be exposed to the outside of the body shell, with the consequence that when performing a maintenance operation for the air purifier, it does not become necessary to fix or disassemble the cover of the body. Furthermore, its shape and volume can be freely fixed and, for example, they can be defined in a shape and volume suitable for an effect corresponding to a damping action and the noise damping effect of gases. exhaust or internal combustion engine vibration noise transmitted to the air cleaner for the exhaust gas system can be improved.

Furthermore, the invention described in claim 1 is implemented as described in claim 2, with the consequence that the air cleaner for the exhaust gas system and the shut-off valve oscillate together with the muffler which is part of the combustion engine assembly. internal oscillating system, so that the secondary air supply duct that connects the air purifier for the gas exhaust system, the shut-off valve and the gas exhaust system (connecting part of the secondary air supply) is made in such a way as to allow its lengthening or shortening due to oscillations of the internal combustion engine unit and therefore the length of each of the sections and the overall length of the elements can be shortened.

Furthermore, since the air cleaner for the exhaust gas system and the shut-off valve are arranged together at the muffler, the whole secondary air supply device can be arranged in a compact form. Furthermore, the air cleaner for the exhaust gas system and the shut-off valve are arranged to be exposed to the outside of the body shell, with the consequence that it does not become necessary that, when a maintenance operation is performed for these parts, the body upholstery is fixed or disassembled.

Also, since the shut-off valve is arranged in a spacing relationship from the internal combustion engine, it cannot be affected by heat damage.

Further, the invention described in claim 3 consists of a secondary air supply device for a small motorcycle exhaust system in which secondary air is supplied to the small motorcycle exhaust system through a secondary air supply duct whose terminal end is connected to the air purifier for the gas exhaust system and having an on-off valve mounted in its central part, characterized in that the aforementioned on-off valve is arranged in correspondence with a muffler.

Since the invention described in claim 3 is constructed as described above, the shut-off valve is arranged to be exposed to the outside of the body lining and its maintenance characteristics are improved. Furthermore, since the shut-off valve swings together with the muffler which is part of the oscillating internal combustion engine assembly, it does not become necessary for the part of the secondary air supply line that connects the shut-off valve with the exhaust gas system ( connection part of the secondary air supply duct) is made in such a way as to allow the absorption of its elongation or shortening produced by oscillations of the internal combustion engine, and therefore its length can be shortened. Also, since the shut-off valve is arranged in a spacing relationship with respect to the internal combustion engine, it cannot be affected by damage from the heat of the engine.

Further, the invention described in claim 3 is embodied as described in claim 4, and the air cleaner for the exhaust gas system is oscillated together with the motion transmission device which is part of the oscillating internal combustion engine assembly. , with the consequence that it does not become necessary that the part of the secondary air supply duct which connects the air purifier for the gas exhaust system with the shut-off valve is made in such a way as to allow the absorption of its elongation or of the its shortening produced by the oscillation of the internal combustion engine unit, its length can be shortened and furthermore the overall length of the secondary air supply duct can be shortened.

Furthermore, the invention described in claim 3 is embodied as described in claim 5 to make the air cleaner for the gas exhaust system be made easily. Furthermore, since a single air cleaner housing or fixing bracket or the like is not required, the number of component parts can be reduced.

Furthermore, since the air cleaner for the exhaust gas system is also swung together with the air cleaner for the gas intake system which is part of the oscillating internal combustion engine assembly, with the consequence that it does not become necessary for the part of the secondary air supply duct that connects the air cleaner for the gas exhaust system with the shut-off valve is made in such a way as to allow the absorption of its elongation or shortening produced by the oscillation of the engine a internal combustion, its length can be shortened and furthermore the overall length of the secondary air supply duct can be shortened.

Further, the invention described in claim 5 is embodied as described in claim 6, whereby a simple passage of the terminal end of the secondary air supply duct through the air cleaner enclosure for the air intake system and its connection allows to obtain the purified secondary air for the gas exhaust system, so that the realization of the air purifier for the gas exhaust system is further facilitated.

Furthermore, the invention described in claim 5 is implemented as described in claim 7, whereby mutual interference is prevented between the supply system for the secondary air supplied to the exhaust gas system and the supply system for the air. primary fed to the air intake system.

Further, the invention described in claim 7 is embodied as described in claim 8, whereby it is possible to easily perform the manufacture of each of the air intake ports between the air cleaner for the exhaust gas system and the air for the air intake system.

Furthermore, the invention described in claim 7 is implemented as described in claim 9, whereby a mutual interference between the supply system for the secondary air supplied to the gas exhaust system and the supply system for primary air fed to the air intake system.

Furthermore, the invention described in claim 3 is implemented as described in claim 10, whereby it is possible to fix the air cleaner for the exhaust system rigidly to the vehicle frame and at the same time it is possible to maintain the appearance characteristics exterior of the muffler and air cleaner for the air intake system.

Further the invention described in claim 3 is embodied as described in claim 11, whereby the air cleaner for the exhaust gas system is swung together with the internal combustion engine, with the result that it does not become necessary for the part of the secondary air supply duct that connects the air purifier for the gas exhaust system with the shut-off valve is made in such a way as to allow the absorption of its elongation or shortening produced by oscillations of the internal combustion engine unit , its length can be shortened and furthermore the overall length of the secondary air supply duct can be shortened.

It is also possible that the air cleaner for the exhaust gas system is exposed at the lining of the internal combustion engine in the same position as the main body of the muffler, so that the air cleaner for the exhaust system of the gases and the shut-off valve can be arranged close to each other, with the result that the entire secondary air supply device can be arranged compactly.

Furthermore, the invention described in claim 11 is embodied as described in claim 12, whereby the manufacture of the air cleaner for the gas exhaust system can become easy. Furthermore, it is not necessary to have a single air cleaner enclosure or a fixed support or the like, and it is possible to reduce the number of component parts.

Further the invention described in claim 13 consists of a secondary air supply device for a small motorcycle exhaust system in which secondary air is supplied to the small motorcycle exhaust system through a duct of secondary air supply whose terminal end is connected to the air purifier for the gas exhaust system and having an interception valve mounted in its central part, characterized in that it is the aforementioned air purifier for the exhaust system of the gas and the aforementioned shut-off valve are arranged under a section of the platform.

Since the invention described in claim 13 is implemented as described above, it is possible that the air cleaner for the exhaust gas system and the shut-off valve are arranged together near the suspension arm of the internal combustion engine, whereby the length of the secondary air supply duct can be shortened and at the same time the whole secondary air supply device can be made compact.

Furthermore, the invention described in claim 13 is embodied as described in claim 15, whereby the length of the secondary air supply duct can be shortened.

Furthermore, the invention described in any one of claims 1 to 14 is implemented as described in claim 15, whereby it is possible to facilitate the maintenance operation of the main body of the muffler, of the secondary air supply device arranged in correspondence with the main body of the aforementioned muffler (the air cleaner for the exhaust gas system and the shut-off valve) and of the rear wheel or the like.

Furthermore, the invention described in any one of claims 1 to 15 is implemented as described in claim 16, the attachment or disassembly of the muffler, or of the secondary air supply device (the air cleaner for the exhaust system of the gas, the shut-off valve) arranged in correspondence with the aforementioned muffler or under the platform section can be easily performed and at the same time even if these parts are not completely disassembled from the vehicle, the maintenance operation of these parts as well as of the rear wheel can be performed more easily. In addition, the vehicle can be made with a low weight.

Furthermore, the invention described in any one of claims 1 to 16 is embodied as described in claim 17, and it is possible that the exhaust gases of the two-stroke internal combustion engine are completely burned, sufficiently purified and discharged.

Furthermore, the invention described in any one of claims 1 to 17 is implemented as described in claim 18, whereby it is possible to improve a sound damping effect with reference to the internal combustion engine exhaust gas noise or vibrating noise. of the shut-off valve transmitted to the air cleaner for the exhaust gas system.

The invention will be described below with reference to the attached drawings, in which:

Figure 1 is a side elevational view showing a small motorcycle equipped with a secondary air supply device for a gas exhaust system forming part of a preferred embodiment (preferred embodiment 1) of the present invention described in claims 1 to 3 and claims 15 to 18;

Figure 2 is a side elevation view, partially in longitudinal section, in which a substantial part of Figure 1 is enlarged;

Figure 3 is a schematic top plan view, partially in cross section, in which a substantial part of Figure 1 (the internal combustion engine assembly) is enlarged;

Figure 4 is a side elevational view, partially in longitudinal section, to show only a portion of the muffler in Figure 2;

Figure 5 is a schematic top plan view, partially in cross section, to show the internal combustion engine unit provided with the secondary air supply device for the exhaust gas system forming part of a preferred embodiment ( preferred embodiment 2) of the present invention described in claim 4 of the present invention, and this figure corresponds to figure 3;

Figure 6 is a schematic top plan view to show the internal combustion engine assembly provided with the secondary air supply device for the gas exhaust system forming part of a preferred embodiment (preferred embodiment 3) of the present invention described in claims 5 and 6 of the present invention, and this figure corresponds to figure 3;

Figure 7 is a cross-sectional top plan view to show a shell portion of the air cleaner in Figure 6;

Figure 8 is a schematic top plan view to show the internal combustion engine assembly provided with the secondary air supply device for the gas exhaust system forming part of a preferred embodiment (preferred embodiment 4) of the present invention described in claims 7 and 8 of the present invention, and this figure corresponds to figure 3;

Figure 9 is a cross-sectional top plan view to show a housing portion of the air cleaner in Figure 8,

Figure 10 is a cross-sectional top plan view to show a housing part of an air cleaner in the secondary air supply device for the exhaust gas system forming part of a preferred embodiment (FIG. preferred embodiment 5) of the present invention described in claim 8 of the present invention, and this figure corresponds to figure 9;

Figure 11 is a side elevational view showing a small-sized motorcycle equipped with the secondary air supply device for the exhaust gas system forming part of a preferred embodiment (preferred embodiment 6) of the present invention described in claim 10 of the present invention;

Figure 12 is a schematic top plan view to show a part of the internal combustion engine assembly provided with the secondary air supply device for the exhaust gas system forming part of a preferred embodiment (preferred embodiment 7) of the present invention described in claim 11 of the present invention;

Figure 13 is a side elevational view to show a substantial portion looking along a direction XIII in Figure 12, with a portion thereof interrupted;

Figure 14 is a side elevational view to show a substantial part of the secondary air supply device for the exhaust gas system forming part of a preferred embodiment (preferred embodiment 8) of the present invention described in claim 12 of the present invention, with an interrupted part thereof, and this figure corresponds to figure 13;

Figure 15 is a side elevational view showing a small motorcycle equipped with the secondary air supply device for the exhaust gas system forming part of a preferred embodiment (preferred embodiment 9) of the present invention described in claims 13 and 14 of the present invention,

Figure 16 is a schematic top plan view, partially in cross section, in which a substantial part of Figure 15 is enlarged, and this figure corresponds to Figure 3; And

Figure 17 is similar to Figure 15, and shows an example of modification of a preferred embodiment (preferred embodiment 9) illustrated in Figure 15.

First, a preferred embodiment of the invention (preferred embodiment 1) described in claims 1 to 3, and in claims 15 to 18, illustrated in figures 1 to 4, will be described below.

In these figures, 1 indicates a scooter-type motorcycle in which a secondary air supply device is applied to an exhaust system according to a preferred embodiment 1 of the present invention illustrated in a side elevation view from the left, and 2 indicates a saddle, in which a steering head 4 projects upwards, with a lowered footboard section 3 spaced in a front part of the saddle.

A rotary handlebar shaft 6 rotated through a handlebar 5 is pivotally supported at a head tube 7 and a front wheel 9 is suspended at the lower end of the shaft through a front fork 8. Hence, a descending frame 10 extends from the head tube 7 in a downward direction, branches out into its lower section in a right and a left side, extending at the footrest section 3 in a rearward facing direction and hence the frame descending is connected to a rear frame 11. The rear frame 11 extends in an oblique direction facing upwards and backwards and reaches the lower part of the rear end of the saddle 2.

The front section of the vehicle body, the framework of which is formed by this descending frame 10 and this rear frame 11, is provided with a shield 12 which covers the rear section of the descending frame 10 and extends along this rear section, in which the shield 12 extends in a rearward and downward facing direction and is connected to a footboard covering 13 which covers a central footboard section of the vehicle body. Then the footboard liner 13 is connected to the body liner 14 which covers the rearward extending section of the rear frame where it faces upward from its horizontal section to the oblique rear section, the body liner 14 is connected to a central lining 15 at its front upper section and the central lining 15 covers, together with the front saddle 2, the front section of a fuel tank 16 arranged under the saddle 2.

17 indicates an internal combustion engine unit (oscillating unit) usable for the suspension of a rear wheel, in which its front section is fixed to the lower front section of the rear frame through a suspension arm 18 so as to be able to swing in a upward or downward direction and its rear section is suspended at the rear section of the rear frame 11 through a shock absorber assembly 19.

An internal combustion engine 20 is integrally arranged in the front section of the internal combustion engine unit 17 and a rear wheel 21 is arranged in an articulated manner in its rear section. Hence a motion transmission device (a continuously variable belt gearbox) 22 which can be used to transmit the motion from the internal combustion engine 20 to the rear wheel 21, and a muffler 28 which constitutes an element forming part of a gas exhaust system which will be described below, are integrally arranged in correspondence with the combustion engine unit internal 17, with the rear wheel 21 arranged between them.

The internal combustion engine 20 is a two-stroke internal combustion engine in which an intake system consisting of an air cleaner 23, a carburetor 24 and an intake duct 25 is connected to an intake port (not shown) of the internal combustion engine 20.

The exhaust duct 27 extends from an exhaust port 26 arranged at a cylinder section of the internal combustion engine 20 in a forward and downward facing direction, subsequently it is curved and directed in a rearward facing direction , a main body 30 of the muffler is connected in cooperative relationship with its rear portion, and the muffler 28 consists of these members.

The exhaust duct 27 and the main body 30 of the muffler are connected in a detachable manner at a connection part 31 so that the flanges of each of them are connected in a detachable manner by means of a coupling means consisting of a screw and a dice.

As illustrated in Figure 2, inside the main body 30 of the muffler there is contained a catalytic converter 32 composed of a metal catalyst, in which the exhaust gas fed by the exhaust duct 27 undergoes an oxidation reaction in the catalytic converter 32 becoming completely burnt gas and the gas is discharged into the external atmosphere as it is purified.

Secondary air is also supplied to the aforementioned exhaust system, and the exhaust gas purification effect with the aforementioned catalytic converter 32 is improved. This secondary air is supplied from a secondary air inlet port 34 formed relatively close to a section connected to the exhaust port 26 of the internal combustion engine 20 via a secondary air supply system which will be described below.

The aforementioned secondary air supply system consists of an air purifier 35 for an exhaust system, an interception valve consisting of a reed valve 36, and a secondary air supply duct 37 which connects these members and which connects furthermore the latter to the aforementioned secondary air supply inlet 34. The secondary air supply duct 37 consists of a flexible rubber tube 38 which connects the air cleaner 35 for the exhaust system to the reed valve 36, to be a rubber hose 39 on the side of the reed valve 36 which connects the reed valve 36 to the secondary air supply inlet 34, and from a metal conduit 40 at the secondary air supply inlet 34.

The rubber hose can be separated at connecting sections 37a, 37b and furthermore the hose is dismountable with respect to the reed valve 36 at a connection part 37d with the reed valve 36. The hose rubber hose 39 is also detachably disposed with respect to reed valve 36 at the connecting part 37 and with reed valve 36. Furthermore, the rubber hose 39 and the metal conduit 40 are detachably arranged in correspondence with of a connection part 37c arranged at a point substantially intermediate between the reed valve 36 and the inlet port for the supply of secondary air 34.

The aforementioned air cleaner 35 for the exhaust system is attached to the rear section of a cockscomb-shaped vertical fixing piece 41 (see figure 4) vertically fixed to an upper end of the main body 30 of the muffler with its inlet air intake 35a directed in a forward and downward facing direction by some fastening means 42 consisting of screws and nuts, wherein one side of a clean air chamber 35b within the air purification chamber is divided by a partition plate 35c into two chambers, the two chambers are put in communication through a communication duct 35d, the air purified by a filter 35e passes through these two chambers, exits through an outlet port 35f and is guided towards a flexible tube rubber tube 38 of the secondary air supply duct 37.

The aforementioned reed valve 36 is fixed, by means of connection means 44 consisting of screws and nuts, to the two front and rear arms 43a, 43b which extend in a horizontal direction from the fixing piece 43 fixed to a wide front section of the piece of vertical fixing 41.

Hence, this exhaust system air cleaner 35 and reed valve 36 are shielded from heat by the muffler lining 45 relative to the muffler main body 30. The aforementioned muffler liner 45 is attached to the muffler main body 30 with a predetermined clearance while a slotted portion 45a in its upper section is coupled with a welded foot 41a of the vertical fastening piece 41.

Since the preferred embodiment 1 is constructed as previously described, both the air cleaner 35 and the reed valve 36 for the exhaust system are arranged to be exposed to the outside of the body shell 14, and it does not become necessary fix or remove the cover 14 of the body.

Furthermore, it becomes possible to freely determine the shape and volume of the air cleaner 35 for the exhaust system and the exhaust noise of the internal combustion engine transmitted to the air cleaner 35 for the exhaust system or the vibration noise of the valve. lamella 36 can be effectively damped by making its shape cylindrical or by increasing its volume or by dividing the clean air chamber 35b in the chamber into a plurality of communicating chambers in series.

Furthermore, both the air cleaner 35 and the reed valve 36 for the exhaust system oscillate together with the oscillating main body 30 of the muffler forming part of the internal combustion engine assembly 17, so that it is not necessary to make each of the sections 38, 39, 40 of the secondary air supply duct 37 which connects the air cleaner 35, the reed valve 36 for the exhaust system and the inlet port for the secondary air supply 34, so that they can absorb stretches or shortenings produced by the internal combustion engine unit 17, and therefore the length of each of the sections 38, 39 and 40 and their overall length can be shortened.

Furthermore, since both the air cleaner 35 and the reed valve 36 for the exhaust system are arranged as a whole in correspondence with the main body 30 of the muffler, it is possible to arrange the entire secondary air supply device in a compact manner.

Further, since the reed valve 36 is disposed in a spaced relationship with respect to the internal combustion engine 20, there is no possibility that it will be damaged by the heat of the engine.

Furthermore, in the case in which the main body 30 of the muffler, the secondary air supply device (the air cleaner 35 for the exhaust system and the reed valve 36} arranged in correspondence with the aforementioned main body 30 of the muffler and the rear wheel 21 or the like are repaired and maintained, the main body 30 of the muffler can be disassembled together with the secondary air supply device, the rear wheel 21 can be removed so as to allow operations to be easily carried out for the the fact that the main body 30 of the muffler is made in such a way that it can be freely fixed or disassembled together with the exhaust duct 27.

In this case, since the rubber hose 39 is removably disposed at the connecting part 37c against the metal conduit 40, the rubber hose 39 is removed from the metal conduit 40 or the connecting condition at the metal conduit part 37e is eliminated so as to allow the rubber hose 39 to be removed from the reed valve 36, whereby the main body 30 of the muffler and the secondary air supply device arranged at the main body 30 of the muffler can be completely separated from the vehicle. With such a preceding arrangement, the aforementioned maintenance operation can be performed more easily.

Since the rubber hose 39 has a certain flexibility, the above maintenance operation can be easily performed even if the main body 30 of the muffler and the secondary air supply device arranged at the main body 30 of the muffler are not completely separated as previously described.

furthermore, since the metal catalyst is contained in the main body 30 of the muffler, it is possible to carry out a complete combustion of the exhaust gases containing not yet burned substances discharged from the two-stroke internal combustion engine 20 through the metal catalyst and the secondary air supplied to the gas exhaust system, and carry out their sufficient purification at the same time as their exhaust operation.

A preferred embodiment of the present invention (preferred embodiment 2) described in claim 4 of the present invention and illustrated in Figure 5 will now be described.

In the preferred embodiment 2, the air cleaner 35 for the gas exhaust system in the secondary air supply device is fixed and arranged on the housing of a motion transmission device (continuously variable belt gear) 22 through the air cleaner 23 for a suction system through connection means consisting of screws and nuts, not shown. Since the other configurations are similar to those of the preferred embodiment 1, their detailed description will be eliminated.

Since the preferred embodiment 2 is constructed as described above, the air cleaner 35 for the exhaust gas system can also be made to oscillate in this case together with the motion transmission device 22 which is part of the combustion engine assembly. internal oscillating 17. Consequently, a part of the secondary air supply duct (rubber hose) 38 is not required to connect the air cleaner 35 with the reed valve 36 for the exhaust gas system to be made of so as to be able to absorb its elongation or contraction produced by the oscillation of the internal combustion engine unit 17, its length can be shortened and furthermore the overall length of the secondary air supply duct 37 can be shortened.

A preferred embodiment will now be described (preferred embodiment 3) described in claim 5 and claim 6 of the present invention and illustrated in Figures 6 and 7.

In the preferred embodiment 3 of the present invention, the air cleaner 35 for the gas exhaust system in the secondary air supply device is made integrally with the air cleaner 23 for the gas intake system with joint use of a single air purification chamber 23a. Since the other configurations are similar to those of the preferred embodiment 1, their detailed description will be eliminated. Additionally, 23e indicates an air intake port.

Since the preferred embodiment 3 of the present invention is constructed as previously described, the simple passage of the terminal end of the secondary air supply duct section (rubber hose) 38 through the inner casing 23b of the air cleaner 23 for the gas suction system and its connection allow to obtain the purified secondary air for the gas exhaust system, so the realization of the air purifier 35 for the gas exhaust system becomes quite easy, it is not required a separate housing of the air cleaner or a fixing bracket or the like, and the number of component parts can be reduced. Further, 23c indicates an outer casing for the air cleaner for the air intake system.

Furthermore, also in this case, the air cleaner 35 for the exhaust gas system can be swung together with the air cleaner 23 for the gas intake system which is part of the oscillating internal combustion engine assembly 17. Di Consequently, it is not necessary that a part of the secondary air supply duct (rubber hose) 38 to connect the air cleaner 35 for the exhaust gas system with the reed valve 36 is made in such a way as to be able to absorb the its lengthening or its contraction produced by the oscillation of the internal combustion engine unit 17, its length can be shortened and furthermore the entire length of the secondary air supply duct 37 can be shortened.

A preferred embodiment will now be described (preferred embodiment 4) described in claim 7 and claim 8 of the present invention and illustrated in Figures 8 and 9.

In the preferred embodiment 4 of the present invention, which differs from the preferred embodiment 3, the air cleaner 35 for the gas suction system in the secondary air supply device is integrally formed with the air cleaner 23 for the system gas suction while each of the air purification chambers 35g, 23d is separated from the other. Hence, these air cleaning chambers 35g, 23d have a common air intake inlet 23e. 23f indicates a partition wall for separating these two air cleaning chambers 35g, 23d. 23g indicates a filter disposed across the two air purification chambers 35g, 23d. The other configurations are similar to those of the preferred embodiment 3, and their detailed description will be eliminated.

Since the preferred embodiment 4 of the present invention is constructed as described above, mutual interference is prevented between a system for supplying secondary air fed to the exhaust gas system for purifying the exhaust gases of the internal combustion engine 20 and a system for supplying primary air fed to the gas intake system as combustion air for the internal combustion engine 20.

Further, each of the air intake ports between the air cleaner 35 for the gas exhaust system and the air cleaner 23 for the gas intake system can be formed easily.

A preferred embodiment (preferred embodiment 5) described in claim 9 of the present invention and illustrated in Figure 10 will now be described.

In the preferred embodiment 5 of the present invention, which differs from the preferred embodiment 4, the two aforementioned air purification chambers 35g, 23d have separate air intake ports 35h, 23h. For this fact, the two air purification chambers 35g, 23d are completely separated by a partition wall 23i arranged vertically in correspondence with a common internal casing 23b and by a partition wall 23j arranged vertically in correspondence with a common external casing 23c .

Furthermore, a filter 35i for the air cleaner 35 for the exhaust gas system and a filter 23k for the air cleaner 23 for the gas suction system are arranged separately and their inner ends are blocked and supported by grooves formed at the end of the partition wall 23i in an opposite direction, as shown in the figure. Since the other configurations are similar to those of the preferred embodiment 4, their detailed description will be eliminated.

Since the preferred embodiment 5 is constructed as described above, mutual interference between the secondary air supply system and the primary air supply system is further prevented.

A preferred embodiment will now be described (preferred embodiment 6) described in claim 10 of the present invention and illustrated in Figure 11.

In the preferred embodiment 6 of the present invention, which differs from the preferred embodiments 1 to 5, the air cleaner 35 for the gas exhaust system in the secondary air supply device is connected to and arranged at the rear frame 11 by connector means 46 using screws and nuts or the like so that the air cleaner can be disposed in an empty space between the screen 47 for the internal combustion engine 20 and the liner 14 of the body. Hence, the air cleaner 35 for the exhaust gas system and the reed valve 36 are connected by the section (rubber hose) 38 of the secondary air supply duct. Since the other configurations are similar to those of the preferred embodiment 1, their detailed description will be eliminated.

Since the preferred embodiment 6 of the present invention is constructed as described above, it is possible to fix the air cleaner 35 for the gas exhaust system to the rear frame 11 in a rigid manner. Furthermore, the external appearance characteristics of the main body 30 of the muffler and of the air cleaner 23 for the gas intake system are not compromised.

A preferred embodiment (preferred embodiment 7) of the present invention described in claim 11 and illustrated in figures 12 and 13 will now be described.

In the preferred embodiment 7 of the present invention, which differs from the preferred embodiments 1 to 6, the air cleaner 35 for the gas exhaust system in the secondary air supply device is attached to and arranged at the right side surface of the shield 47 of the internal combustion engine 20 by a connecting means 48 using a screw and a nut. Since the other configurations are similar to those of the preferred embodiment 1, their detailed description will be eliminated.

Further, the shield 47 covers the cylinder portion of the internal combustion engine 20, and the surrounding atmosphere is drawn in by a cold air intake port formed at the front or left side surface by a fan and flows into the shield. 40 so as to forcefully cool the cylinder part (not shown).

Since the preferred embodiment 7 of the present invention is constructed as described above, the air cleaner 35 for the exhaust gas system can be swung together with the internal combustion engine 20. Consequently, it does not become necessary for the section (rubber hose) 38 of the secondary air supply duct used to connect the air purifier 35 for the gas exhaust system to the reed valve 36 is made in such a way as to allow the absorption of an elongation thereof or of a its contraction due to oscillations of the internal combustion engine unit 17, with the consequence that its length can be shortened and furthermore the entire length of the secondary air supply duct 37 can be shortened.

Furthermore, the air cleaner 35 for the gas exhaust system is arranged at the right side surface of the screen 47 arranged on the same side as the main body 30 of the muffler, it is possible that the air cleaner 35 for the exhaust system gas and the reed valve 36 are arranged to be close to each other and furthermore the whole secondary air supply device can be arranged in a compact size.

A preferred embodiment (preferred embodiment 8) of the present invention described in claim 12 and illustrated in Figure 14 will now be described.

In the preferred embodiment 8 of the present invention, which differs from the preferred embodiment 7, the air cleaner 35 for the gas exhaust system in the secondary air supply device is made and integrally arranged at the outer wall of the screen 47 of the internal combustion engine 20.

For this fact, an inner casing 35j of the air cleaner 35 for the exhaust gas system is integrally formed with the casing of the shield 47 of the internal combustion engine 20. The outer casing 35k is formed separately in order to facilitate the fixing and maintenance of the filter 351. Since the other configurations are similar to those of the preferred embodiment 7, their detailed description will be eliminated.

The preferred embodiment 8 of the present invention is constructed as described above, and it becomes easy to form the air cleaner 35 for the gas exhaust system. Furthermore, since it is not necessary to prepare a separate air cleaner or a fixing bracket or the like, it is possible to reduce the number of component parts.

A preferred embodiment (preferred embodiment 9) of the present invention will now be described, described in claims 13 and 14 and illustrated in figures 14 to 17.

In the preferred embodiment 9, which differs from preferred embodiments 1 to 8, the air cleaner 35 for the exhaust gas system and the reed valve 36 in the secondary air supply device are attached to, and arranged at a horizontal extension part of a descending frame 10 under the platform 3 by means of a connection means (not shown) using a support extending from the descending frame 10, a screw and a nut.

Then, a secondary air supply duct 37 used to connect the air cleaner 35 for the exhaust gas system and the reed valve 36 to the secondary air intake port 34 formed at the exhaust gas duct 27 of the internal combustion engine 20 (see Figure 16), is arranged to pass through a position near the suspension ring 18 for the internal combustion engine assembly 17.

In this case, Figures 15 and 16 illustrate a condition in which the present device is applied to a small-sized motorcycle equipped with a vertical internal combustion engine 20 slightly inclined from its vertical line in a rearward-facing direction, and the Figure 17 illustrates another condition in which the present device is applied to a small motorcycle equipped with a horizontal internal combustion engine 20 slightly raised from its horizontal level and positioned, respectively.

In the preferred embodiment 9, in the event that a maintenance operation is performed for the air cleaner 35 for the gas exhaust system or for the reed valve 36, a sump 50 (figures 15, 17) is removed from the vehicle.

Since the present preferred embodiment 9 is constructed as described above, it is possible that the air cleaner 35 for the exhaust gas system and the reed valve 36 are arranged together near the suspension arm 18 of the internal combustion engine assembly. 17, whereby it is possible to shorten the length of the secondary air supply duct 37. Furthermore, the entire secondary air supply device can be arranged in compact form.

Claims (18)

CLAIMS 1. Secondary air supply device for a small motorcycle exhaust system, where secondary air is supplied to the small motorcycle exhaust system through a secondary air supply duct whose end terminal is connected to the air purifier for the gas exhaust system and having an interception valve mounted in its central part; characterized in that the aforementioned air cleaner for the gas exhaust system is arranged in correspondence with a muffler. 2. Secondary air supply device for a small-sized motorcycle exhaust system according to claim 1, characterized in that the aforesaid shut-off valve is also installed at the aforesaid muffler. 3. Secondary air supply device for a small motorcycle exhaust system, where secondary air is supplied to the small motorcycle exhaust system through a secondary air supply duct whose end terminal is connected to the air purifier for the gas exhaust system and having an interception valve installed in its central part; characterized in that the aforesaid interception valve is arranged in correspondence with a muffler. 4. Secondary air supply device for a small motorcycle exhaust system according to claim 3, characterized in that the aforementioned air cleaner for the exhaust system is arranged side by side on a housing of a motion transmission device in front of the air cleaner for a gas suction system. 5. Secondary air supply device for a small motorcycle exhaust system according to claim 3, characterized in that the aforementioned air cleaner for the exhaust system is integrally formed with the air cleaner above for the gas suction system. 6. Secondary air supply device for a small motorcycle exhaust system according to claim 5, characterized in that the aforementioned air cleaner for the exhaust system is integrally formed with the air cleaner above for the gas suction system in cooperation with a single air purification chamber. 7. Secondary air supply device for a small motorcycle exhaust system according to claim 5, characterized in that the aforementioned air cleaner for the exhaust system is integrally formed with the air cleaner above for the gas suction system, with each of the air purification chambers separated from each other. 8. Secondary air supply device for a small motorcycle exhaust system according to claim 7, characterized in that each of the aforementioned air purification chambers has a common air intake port. 9. Secondary air supply device for a small motorcycle exhaust system according to claim 7, characterized in that each of the aforementioned air purification chambers has a separate air intake port. 10. Secondary air supply device for a small motorcycle exhaust system according to claim 3, characterized in that the aforementioned air cleaner for the exhaust system is arranged at the rear frame. 11. Secondary air supply device for a small motorcycle exhaust system according to claim 3, characterized in that the aforementioned air cleaner for the exhaust system is arranged at a an internal combustion engine. 12. Secondary air supply device for a small motorcycle exhaust system according to claim 11, characterized in that the aforementioned air cleaner for the exhaust system is integrally formed with an engine screen internal combustion aforementioned. 13. Secondary air supply device for a small motorcycle exhaust system, in which secondary air is supplied to the small motorcycle exhaust system through a secondary air supply duct whose terminal end is connected to the air purifier for the gas exhaust system and having a shut-off valve mounted in its central part, characterized in that both the aforementioned air purifier for the gas discharge system and the aforementioned shut-off valve are arranged under a footboard section. 14. Secondary air supply device for a small motorcycle exhaust system according to claim 13, characterized in that said secondary air supply duct is disposed through a point close to the suspension arm of the internal combustion engine unit. 15. Secondary air supply device for a small-sized motorcycle exhaust system according to any one of claims 1 to 14, characterized in that the muffler consists of the main body of the muffler and the exhaust duct of the gas and this main body of the muffler and this gas exhaust duct are separably formed. 16. Secondary air supply device for a small-sized motorcycle exhaust system according to any one of claims 1 to 15, characterized in that the aforementioned secondary air supply duct running from the shut-off valve to the aforesaid gas discharge system is formed by connecting a flexible pipe at the aforesaid shut-off valve with a metal conduit at the aforesaid gas discharge system. 17. Secondary air supply device for a small motorcycle exhaust system according to any one of claims 1 to 16, characterized in that the internal combustion engine is a two-stroke internal combustion engine and a catalyst is contained in the muffler. 18. Secondary air supply device for a small motorcycle exhaust system according to any one of claims 1 to 17, characterized in that the aforementioned air cleaner for the exhaust system is provided in the its chamber on one side corresponding to a purified air chamber, divided into a multiplicity of communicating rooms in series.