JP3582497B2 - Exhaust gas purification device for scooter type vehicle - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an exhaust gas purification device for a scooter type vehicle having a unit swing engine.
[0002]
[Prior art]
Generally, a scooter-type vehicle is equipped with a so-called unit swing engine integrally provided with a power transmission device for transmitting power to rear wheels. The unit swing engine has a front end rotatably supported by the vehicle body and swings up and down to cause the rear wheels to follow the road surface.
[0003]
Since the unit swing engine is mounted on the rear lower part of the vehicle due to the structure of the scooter type vehicle, the traveling wind hardly hits its cylinder. Therefore, conventionally, an air-cooling fan is provided at the end of the crankshaft, a duct is formed by covering the periphery of the air-cooling fan and the cylinder with a cover, and the cooling air is forcibly blown to the cylinder by the air-cooling fan in the cover. Like that. In some cases, a sound absorbing material is provided on the cover body for forced air cooling or the clutch cover that covers the side surface of the entire engine (see, for example, JP-A-6-200757 and JP-A-1-113513).
[0004]
Also, when secondary air is sucked into the exhaust system of such a unit swing engine for the purpose of purifying exhaust gas, the secondary air is normally passed through an air cleaner and a reed valve dedicated to the secondary air in order to discharge the secondary air to the exhaust section. To be introduced. Various technologies have been conventionally proposed for a secondary air supply device of this type of scooter type vehicle. For example, Japanese Patent Application Laid-Open No. H4-101011 discloses an exhaust purification device for forcibly sending secondary air. Have been. Japanese Patent Application Laid-Open No. 5-163940 discloses a secondary air supply device in which a secondary air reed valve is installed on the cylinder cover.
[0005]
[Problems to be solved by the invention]
As described above, the conventional unit swing engine requires an air cleaner dedicated to the secondary air system, so that there is a problem that the number of components constituting the secondary air system is large and the cost is high. The sound absorbing material provided in the unit swing engine is used only for the purpose of sound absorption, and has no other functions.
[0006]
The present invention has been made in view of the above-described conventional problems, and a place where secondary air is introduced in an exhaust system and an outlet of a secondary air of an exhaust gas purification device are close to each other, and the outlet and the exhaust system It is an object of the present invention to provide an exhaust gas purifying apparatus for a scooter type vehicle, in which a connecting member for connecting the components can be shortened and the number of components of the secondary air system can be reduced and the cost can be reduced.
[0007]
[Means for Solving the Problems]
The present invention has the following configuration to achieve the above object.
The present invention, the rear axle front as well as rotatably supported at the rear is rotatably supported on the vehicle body at the bracket for the engine suspension and can swing in the vertical direction, and the engine body and the power transmission apparatus Equipped with a unit swing engine that is integrally assembled , and the secondary air that passes through the filter after being introduced from the inlet that introduces the secondary air passes through the suction pipe and then to the exhaust system through the reed valve equipped with an exhaust gas purifying apparatus for supplying, to place the storage box in a rear cover which covers the seat lower space, Te exhaust gas purification apparatus smell of the scooter type vehicle to form a footrest space for the driver on the front of the seat and disposing the exhaust gas purification device below the storage box, said pipe the suction pipe through the secondary air passing through the filter to the engine body upper unit Connected to the reed valve attached to the front of the engine, the side view of the vehicle, the connection point between the inlet for introducing secondary air to the filter and the exhaust system sandwiched the engine suspension bracket in the vehicle longitudinal direction. An exhaust gas purifying apparatus for a scooter-type vehicle, wherein a secondary air passage is formed in a state .
In the present invention, the filter for the secondary air of the exhaust gas purifying device is arranged on the front side of the vehicle of the air cleaner for purifying the air sent to the carburetor, and the inlet of the air passing through the filter is moved to the space below the seat. It may be below the covering rear cover and outside the rear cover space.
[0008]
According to the present invention, the secondary air passes through the filter and is sucked as secondary air from the suction port of the exhaust system. In addition, the location where the secondary air is introduced in the exhaust system and the outlet of the secondary air of the exhaust gas purification device are close to each other, and the connecting member that connects the outlet and the exhaust system is short, and the components of the secondary air system are required. , The cost and the size of the vehicle can be reduced.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIGS. 1 and 2 are diagrams showing the configuration of the exhaust gas purifying apparatus of the first embodiment. FIGS. 3 and 4 are diagrams showing the configuration of the exhaust gas purifying apparatus of the second embodiment. The common configuration other than the configuration specific to the embodiment (specifically, the configuration of the cover body provided with the sound absorbing material, etc.) is the same in each drawing, and therefore, even in the first embodiment, the description of the common configuration will be omitted. Reference is also made to FIGS. 3 and 4 as appropriate.
[0010]
First, an exhaust gas purifying apparatus for a scooter type vehicle according to a first embodiment will be described. The scooter type vehicle according to the first embodiment includes a front wheel 2 and a rear wheel 4, as shown in FIG. A footrest space S for the driver is formed between the steering wheel 6 for steering the front wheel 2 and the driver's seat 8 disposed above and in front of the rear wheel 4. At the lower end of the footrest space S, a footrest floor 12 supported by the body frame 10 is provided. From the rear end of the footrest floor 12, a rear cover 14 surrounds the lower space of the seat 8. Is provided. A storage box 16 used to open and close the seat 8 is formed in the rear cover 14. The storage box 16 accommodates, for example, a helmet 18.
[0011]
A unit swing engine (hereinafter, referred to as “engine”) 20 is mounted below the rear cover 14. As shown in FIG. 2, the engine 20 includes an engine body 20A mainly composed of a cylinder portion 22 and a crankcase portion 24, and a power transmission device 20B for transmitting power taken out by a crankshaft 26 to a rear wheel shaft 28. They are assembled together. As shown in FIG. 3, the engine 20 includes a carburetor 30 for supplying air-fuel mixture to an engine intake port (not shown), an air cleaner 32 for purifying air sent to the carburetor 30, and an exhaust gas from the cylinder 22. An exhaust muffler 34 connected to the port 22a is provided.
[0012]
As shown in FIG. 2, the crankcase portion 24 includes left and right crankcase halves 24a and 24b. The left crankcase half 24a is formed to the left side of the rear wheel 4 along the left side surface of the rear portion of the vehicle and rotatably supports the rear wheel shaft 28. An engine suspension bracket 36 projects forward from the front of the crankcase 24 (see FIG. 3). The front end of the bracket 36 is connected to the vehicle body frame via a link 40. 10 is rotatably mounted. A cushion unit 42 is interposed between the rear upper portion of the left crankcase half 24a and the rear portion of the vehicle body (see FIG. 3). Therefore, the engine 20 swings up and down with respect to the vehicle body by the bracket 36 and the link 40 and expands and contracts the cushion unit 42, and moves the rear wheel 4 up and down according to the unevenness of the road surface.
[0013]
As shown in FIG. 2, the cylinder portion 22 projects forward and substantially horizontally from the crankshaft 26. Both the upper and lower surfaces and the left side surface of the cylinder portion 22 are covered by a substantially box-shaped cylinder cover 44.
[0014]
At the right end of the crankshaft 26, as shown in FIG. 2, a magnet 46 and an air cooling fan 48 for forcibly taking in cooling air are sequentially provided from the inside. The air cooling fan 48 is fastened to the side end surface of the magnet 46 and is located outside the right crankcase half 24b. The air cooling fan 48 is attached to the side edge of the crankcase half 24b. A fan cover 50 that includes and covers the right side surface of the cylinder portion 22 is fastened. The fan cover 50 has a double structure including an outer cover 50a and an inner cover 50b except for a cooling air inlet 52. The inner cover 50b is formed by further joining left and right half parts. Be composed. The space between the outer cover 50a and the inner cover 50b is filled with a sound-absorbing material 54 having air permeability. As the sound absorbing material 54, for example, a porous body such as a urethane sponge is used. In FIG. 2, reference numeral 56 denotes an oil pump, and reference numeral 58 denotes an ignition coil.
[0015]
As shown in FIG. 2, the power transmission device 20B is a well-known automatic type using a V-belt 60, and is provided at the left end of the crankshaft 26 and has a drive-side pulley around which the front end of the V-belt 60 is wound. Means 62, a driven pulley means 64 around which the rear end of the V-belt 60 is wound, a drive shaft 66 supporting the driven pulley means 64, and a drive shaft 66 driven by the drive shaft 66 via an idle shaft 68. It mainly comprises a final gear 70 for applying power to the wheel shaft 28. The drive shaft 66, the idle shaft 68, and the rear wheel shaft 28 are supported by the crankcase half 24a and a gear case 24a1 provided inside the crankcase half 24a.
[0016]
At the left end of the drive shaft 66, a clutch means 72 for intermittently transmitting power is provided. A clutch cover 74 is fastened to the side edge of the left crankcase half 24a so as to include the front and rear pulleys 62 and 64 and the clutch 72. A kick starter shaft 76 is rotatably provided behind the crankshaft 26, and a left end of the kick starter shaft 76 protruding laterally from the clutch cover 74 is operated by a driver or the like when the engine is started. Kick pedal 78 is fixed.
[0017]
As shown in FIGS. 1 and 2, the exhaust muffler 34 includes an exhaust pipe 34a connected to the exhaust port 22a on the lower surface of the cylinder 22, and a large-diameter muffler 34b connected to the exhaust pipe 34a. The exhaust pipe portion 34a extends rearward through the vicinity of the lower side of the fan cover 50 after being curved in a substantially U shape from the exhaust port 22a, and is connected to the front end of the muffler portion 34b. The muffler portion 34b extends rearward and upward along the right side surface of the rear wheel 4 from near the lower side of the fan cover 50.
[0018]
Subsequently, the configuration of the exhaust gas purification device of the first embodiment will be described. As shown in FIGS. 1 and 2, the exhaust gas purifying apparatus has a secondary air intake port 80 provided near the exhaust port 22a in the exhaust pipe section 34a, and the secondary air intake port 80 is provided inside the fan cover 50. The secondary air that has passed through the sound absorbing material 54 is made to communicate with the sound absorbing material 54 so that the secondary air is sucked into the exhaust muffler 34 from the secondary air suction port 80.
[0019]
That is, at a position behind the cooling air inlet 52 of the outer cover 50a, as shown in FIG. 1, an inlet 82 for introducing the secondary air into the sound absorbing material 54 is opened, while an upper surface of the front end of the outer cover 50a is opened. As shown in FIG. 2, an outlet 84 for taking out the secondary air passing through the sound absorbing material 54 to the outside is provided, and a suction pipe 86 is connected to the outlet 84. The suction pipe 86 is piped from the outlet 84 to the left along the upper surface of the cylinder cover 44, and is connected to the inlet side of a reed valve 88 provided on the left side of the cylinder cover 44. Another suction pipe 90 is connected to the outlet side of the reed valve 88. The suction pipe 90 is piped from the outlet side of the reed valve 88 to the right side near the front lower end of the cylinder cover 44, and then the secondary air Connected to suction port 80.
[0020]
According to the first embodiment having the above-described configuration, the air around the fan cover 50 flows into the sound absorbing material 54 from the inlet 82 provided in the outer cover 50a and passes through the inside of the sound absorbing material 54 (specifically). After the dust and sand are removed by flowing around the upper and lower sides of the substantially oval cooling air inlet 52), the dust is removed from the fan cover 50 through the outlet 84, and further, the suction pipe 86 and the lead are removed. The secondary air is sucked as secondary air from the secondary air suction port 80 into the exhaust portion 34a through the valve 88 and the suction pipe 90 sequentially. Therefore, the sound absorbing material 54 in the fan cover 50 functions as a filter for filtering the secondary air, and an air cleaner and a filter dedicated to the secondary air are not required. Can be reduced in size.
[0021]
Further, since the outlet 84 of the secondary air in the sound absorbing material 54 is arranged on the upper surface of the front end of the outer cover 50a, the secondary air suction port 80 of the exhaust pipe portion 34a and the outlet 84 become closer, and the suction pipes 86 and 90 are shortened. be able to.
[0022]
Next, an exhaust gas purifying apparatus according to a second embodiment will be described. In the second embodiment, as shown in FIGS. 3 and 4, the left side of the engine is different from the first embodiment in which the sound absorbing member 54 provided on the fan cover 50 has a filter function for secondary air. The sound absorbing material 54 is provided on the clutch cover 74 that is configured, and the air passing through the sound absorbing material 54 is sucked into the exhaust portion 34a as secondary air.
[0023]
That is, as shown in FIGS. 3 and 4, the clutch cover 74 has a double structure including an outer cover 74a and an inner cover 74b, and is formed between the outer cover 74a and the inner cover 74b. The gap is filled with the same sound absorbing material 54 as in the first embodiment. An inlet 92 for introducing secondary air into the sound absorbing material 54 is provided at a substantially central portion in the front-rear direction above the outer cover 74a, while a secondary air passing through the sound absorbing material 54 is provided above the front end surface of the outer cover 74a. An outlet 94 is provided to take out the outside. A suction pipe 96 is connected to the outlet 94. The suction pipe 96 extends inward from the outlet 94, and is then connected to an inlet side of a reed valve 88 provided on the left side surface of the cylinder cover 44. . A suction hose 98 connecting the outlet side of the reed valve 88 and the exhaust portion 34a extends forward and downward from the reed valve 88, and then bends to the right to connect to the secondary air intake 80 of the exhaust portion 34a. Is done.
[0024]
According to the second embodiment configured as described above, after the secondary air flows into and passes through the sound absorbing material 54 from the inlet 92 provided in the outer cover 74a of the clutch cover 74 and is purified, the suction hose is passed through the outlet 94. 96. The air that has entered the suction hose 96 is sucked into the exhaust portion 34a via the reed valve 88 and the suction hose 98. In the second embodiment, in addition to the effect that the air cleaner dedicated to the secondary air can be eliminated as in the first embodiment, the installation side of the reed valve 88 (left side of the cylinder cover 44) and the arrangement side of the sound absorbing material 54 ( Since the left side of the engine 20 is shifted to the same side in the left-right direction, a unique effect that the length of the suction pipe 96 can be further reduced can be obtained. In the second embodiment, since the clutch cover 74 having a relatively large area can be filled with a large amount of the sound absorbing material 54, an extremely advantageous effect that secondary air can be satisfactorily purified can be obtained.
[0025]
This embodiment is a preferred embodiment of the present invention, and the technical scope of the present invention is not limited to this embodiment. For example, in the present invention, the engine side cover body provided with the sound absorbing material includes a cover other than the fan cover and the clutch cover (for example, the cylinder cover 44 in the embodiment).
[0026]
【The invention's effect】
As described above, according to the present invention, the number of components of the secondary air system can be reduced, and cost reduction and vehicle miniaturization can be achieved. Further, the connecting member for connecting the outlet of the secondary air and the exhaust system in the sound absorbing material can be shortened.
[Brief description of the drawings]
FIG. 1 is a side view of a scooter type vehicle according to a first embodiment.
FIG. 2 is a cross-sectional view of the unit swing engine viewed from above according to the first embodiment.
FIG. 3 is a side view of a scooter type vehicle according to a second embodiment.
FIG. 4 is a sectional view of a unit swing engine according to a second embodiment as viewed from above.
[Explanation of symbols]
Reference Signs List 20 unit swing engine 28 rear wheel axle 34 exhaust muffler 50 fan cover (an example of a cover on the engine side)
54 Sound absorbing material 74 Clutch cover (an example of a cover body on the engine side)
80 Secondary air inlet 84 Exit 94 Exit

Claims (2)

The rear wheel shaft is rotatably supported at the rear, and the front is rotatably supported by the vehicle body with a bracket for engine suspension so that it can swing up and down. The engine body and the power transmission device are integrally assembled includes a unit swing engine which is, and the exhaust gas supplied from being introduced from the inlet for introducing the secondary air secondary air passing through the filter, the exhaust system via a reed valve from via the suction pipe Equipped with a purifying device, a storage box is disposed in a rear cover that covers the space below the seat, and in a scooter type vehicle exhaust gas purifying device in which a footrest space for a driver is formed in front of the seat,
The reed valve mounted on the front of the unit swing engine by arranging the exhaust gas purifying device below the storage box , piping a suction pipe through which secondary air passing through the filter passes through the upper portion of the engine body, , And a connection point between an inlet for introducing secondary air to the filter and an exhaust system forms a secondary air passage in a state where the bracket for engine suspension is sandwiched in a vehicle longitudinal direction. exhaust gas purification device of the scooter-type vehicle according to claim. The filter for the secondary air of the exhaust gas purifying device is arranged on the front side of the vehicle of the air cleaner for purifying the air sent to the carburetor, and the inlet of the air passing through the filter is positioned below the rear cover covering the lower space of the seat. 2. The exhaust gas purifying apparatus for a scooter-type vehicle according to claim 1, wherein the exhaust gas purifying apparatus is provided outside the rear cover space.

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