JP2002309934A - Secondary air supply system for scooter type vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To downsize by improving space efficiency and to prevent air control valve or the like from being hit by a flying gravel. SOLUTION: In the secondary air supply system for a scooter type vehicle: a unit swing engine 1 is constructed so that an engine portion 1a comprising a cylinder 1c approximately horizontally forward-tilting, a cylinder head 1f, an intake pipe 27 and a carburetor 24 are integrally connected with a power transmitting portion 1b transmitting driving force of the engine portion 1a to a rear wheel 21; the secondary air supply system for supplying secondary air to exhaust gas exhausted from the unit swing engine 1 to purify the exhaust gas is disposed to the unit swing engine 1; and the unit swing engine is mounted on the scooter type vehicle. The air control valve 25 for controlling the secondary air in the secondary air supply system is disposed to a position where it is overlapped with the carburetor 24 and the intake pipe 27, seen from a side of the vehicle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secondary air supply device for a scooter type vehicle for supplying secondary air to exhaust gas derived from a unit swing engine.

[0002]

2. Description of the Related Art Conventionally, a scooter type having an air control valve and a reed valve for supplying secondary air to an exhaust passage in order to enhance a combustion and purification action of a catalyst provided in an exhaust passage of an engine. As vehicles, for example, JP-A-2000-310115 and JP-A-11-311
No. 121 is disclosed.

[0003] Japanese Patent Application Laid-Open No. 2000-310115 discloses an air control valve which is disposed via a stay on a side of a cylinder head or a head cover of a cylinder which is inclined substantially horizontally forward, and a reed valve is provided. This is provided at the front of the cylinder head.

Japanese Patent Application Laid-Open No. 11-311121 discloses a secondary air supply device in which an air control valve and a reed valve are housed in a single housing, and which is provided on a side of a cylinder head of an engine. It is arranged in.

[0005]

However, in the technique described in JP-A-2000-310115,
Since the air control valve is provided on the side of the engine via the stay, the vibration of the engine is easily transmitted to the air control valve via the stay, and the vibration is easy.

Further, since the air control valve also swings at the same time as the unit swing engine swings, it is necessary to maintain the stay at a suitable strength. In addition, as described above, a system in which a reed valve is incorporated into a cylinder head of a cylinder that is tilted substantially horizontally forward (hereinafter, referred to as built-in), and an air control valve is disposed on the side of the cylinder head, allows a Easily exposed to flying stones.

In the device disclosed in Japanese Patent Application Laid-Open No. H11-311121, the air control valve and the reed valve are housed in a single housing, so that the number of parts is reduced and assembly is easy. Although the compactness can be achieved, since the air control valve is arranged on the side of the cylinder head in the vehicle width direction, the air control valve is easily exposed to a stepping stone or the like from the front wheels.

Accordingly, the present invention provides a secondary air supply device for a scooter-type vehicle that can improve the space efficiency and reduce the size, and can prevent the air control valve and the like from being exposed to a stepping stone from the front wheels. It is intended to provide.

[0009]

In order to achieve the above object, the present invention has the following arrangement. That is, the present invention
An engine unit having a cylinder inclined forward substantially horizontally, a cylinder head connected to an upper part of the cylinder, an intake pipe connected to the cylinder head, and a carburetor connected to the intake pipe; A unit swing engine integrally connected to a power transmission unit for transmitting to wheels, wherein secondary air is supplied to exhaust gas derived from the unit swing engine to purify the exhaust gas.
In a secondary air supply device of a scooter type vehicle equipped with a unit swing engine provided with a secondary air supply device, an air control valve for controlling the supply of secondary air in the secondary air supply device is viewed from the side of the vehicle. And is arranged at a position overlapping the carburetor and the intake pipe.

[0010] With this configuration, it is possible to effectively utilize the space at the position overlapping the carburetor and the intake pipe when the vehicle is viewed from the side, thereby improving the space efficiency and preventing a stepping stone or the like from the front wheels. It is possible to prevent the air control valve and the like from being exposed.

The scooter-type vehicle has a storage box capable of storing a helmet or the like above the unit swing engine, and a lower surface of a bottom wall of the storage box is provided to avoid interference with the carburetor and the air control valve. By forming a single interference avoiding recess recessed toward the inside of the storage box, there is no need to separately form a recess for avoiding interference with the air control valve.

By arranging the air control valve so that its height from the ground surface is lower than that of the intake pipe, it is easy to avoid interference with the storage box and the degree of freedom in design is improved. Let me do.

By arranging the fuel tank below and forward of the unit swing engine, it is effective in preventing stepping stones and the like from the front wheels from colliding with the air control valve and the reed valve.

[0014]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective side view of a scooter-type vehicle provided with a secondary air supply device according to one embodiment of the present invention. FIG. 2 shows a main part of a unit swing engine, and FIG. FIG.
FIG. 3A is a plan view of the unit swing engine, as viewed from the direction of arrow I shown in FIG. In the following description, the terms “front and rear,” “up, down,” and “right and left” refer to the vehicle traveling direction of a scooter type vehicle. is there.

The scooter type vehicle A is a two-seater large vehicle equipped with a so-called unit swing engine 1, and the entire body frame 2 is covered with a body cover 3 made of synthetic resin.

The body frame 2 has an upper frame 4 whose front half is formed substantially horizontally, and whose rear half is gradually bent upward. Side standing parts 5a, 5b
The lower frame 5 is formed in a substantially L-shaped side surface, and the auxiliary frame 6 is formed on the front upper portion of the upper frame 4 behind the front rising portion 5a of the lower frame 5.
And these are appropriately connected by welding or the like.

The vehicle body cover 3 is provided with a leg shield 7 and a screen 8 projecting to the left and right sides at the front side, has a backrest 9 and the like at the rear side thereof, and has a helmet H and the like below. A double seat 11 having a storage box 10 to be stored is held, and a pair of left and right plate-shaped ones on which the occupant on the double seat 11 can place his / her feet between the front side of the vehicle body and the double seat 11 are held. Of the floor unit 1 by the footrests 12 and 12 (one of which is not shown) and the upwardly protruding portion 13 provided between the footrests 12 and 12.
4 is formed, and a rear cover 15 is provided on the rear side of the floor portion 14.

A front fork (not shown) is steerably supported on a steering head pipe 16 connected to the front upright portion 5a of the lower frame 5 and the upper end of the auxiliary frame 6, and a lower end of the front fork. The front wheel 17 is pivotally supported by the steering wheel 1 at the upper end.
8 are connected.

A radiator 19 is provided on the front upright portion 5a of the lower frame 5, and is mounted on the lower frame 5 on the rear side of the radiator 19, that is, on the rear side of the front wheel 17. A substantially rectangular parallelepiped fuel tank 20 that is long in the front and rear direction is disposed.

The middle part of the upper frame 4 and the lower frame 5
The unit swing engine 1, which is formed by integrally connecting an engine unit 1 a and a power transmission unit 1 b that transmits the driving force of the engine unit 1 a to the rear wheel 21, It is mounted on the frame so that it can swing up and down.

The unit swing engine 1 has the cylinder 1c of the engine section 1a directed forward of the body frame 2,
This is a water-cooled single-cylinder four-stroke cycle that is inclined substantially horizontally forward. The rear wheel 21 is pivotally supported at the rear of the power transmission part 1b, and the rear part of the power transmission part 1b and the upper A rear shock unit 23 is provided between the rear portions of the frame 4.

The unit swing engine 1 is formed integrally with a crankcase 1d that houses a crankshaft (not shown) and the like and extends behind the crankcase 1d, and transmits the rotational force of the crankshaft to the rear wheel 21. A swing case 1e having a built-in power transmission mechanism (not shown), a cylinder 1c protruding from the front end of the crankcase 1d, a cylinder head 1f, and a cylinder head cover 1g covering the front end of the cylinder head 1f. The shell is composed.

An air control valve 25 for controlling secondary air supplied to exhaust gas derived from the unit swing engine 1 is provided above the cylinder head 1f.
Carburetor 24 and intake pipe 27 as viewed from the side of the vehicle
And the height from the ground surface G is lower than the intake pipe 27 and fixed. More specifically, as shown in FIG. 2 (B), the intake pipe 27 has a cylinder head 1f when viewed from the front of the vehicle.
The air control valve 25 is disposed and fixed so as to be located on the right side of the cylinder head 1f in the width direction of the vehicle body and substantially half the height of the intake pipe 27. ing.

As shown in FIGS. 2 and 3, the air control valve 25 includes a diaphragm that is bent by a pressure difference and a valve body (both not shown) that opens and closes in accordance with the bending of the diaphragm in a cylindrical main body 25a. The main body 25a has an inflow pipe 25b at one end, a control pipe 25d at the other end, and an outflow pipe 25c at the peripheral wall.

The inflow pipe 25b of the main body 25a is provided with an air cleaner 29 described later via an air hose 31, the outflow pipe 25c is provided with a reed valve 26a described later via an air hose 32, and the control pipe 25d is provided with a pipe 33.
The intake pipes 27 are connected to each other via a and 33b. 33c is a pipe 33a, 33
This is a T-shaped branch pipe connecting b.

In the present embodiment, the air hose 31 is piped so as to draw a gentle arc from the air control valve 25 to the air cleaner 29 on the upper side of the cylinder 1c, and supplies the secondary air smoothly. I can do it.

The outer surface of the air cleaner 29 is constituted by an air cleaner case 30. The outer shell is arranged along the upper surface of the swing case 1e, and swings up and down integrally with the swing case 1e. ing.

The carburetor 24 is connected to an air supply port (not shown) of the cylinder head 1f via the intake pipe 27, and to the air cleaner 29 via an inlet tube 28. The carburetor 24 has the fuel tank 20 disposed in front of the cylinder head cover 1g.
Are connected via a fuel pump (not shown).

The reed valve 26a is connected to the cylinder head 1
The lower part of the front end of the cylinder head cover 1g that covers the front end part of the vehicle body f is slightly offset leftward in the vehicle width direction. The reed valve 26a is of a built-in type,
Reed valve cap 26 and cylinder head cover 1
g of the air control valve 25, an inflow pipe 26b for connecting the other end of an air hose 32 connected to the outflow pipe 25c of the air control valve 25 to the other end thereof. However, the cylinder head cover 1g has an outlet hole 26c for connection to an exhaust port 34 provided in the cylinder head 1f.
Are arranged.

In the present embodiment, the air hose 32 is piped in such a manner as to draw a gentle arc in front of the cylinder head cover 1g, so that secondary air can be smoothly led out.

An exhaust pipe 35 for guiding exhaust gas discharged from the exhaust port 34 of the cylinder head 1f extends under the crankcase 1d and extends to the right of the rear wheel 21. The pipe 35 is connected to a muffler 36 disposed on the right side of the rear wheel 21.

The storage box 10 is disposed in the rear half of the upper frame 4 and above the unit swing engine 1. The storage box 10 has a main storage portion 10a having a volume capable of storing the helmet H and the like.
And a sub-housing portion 10b extending in front of the sub-housing portion. The sub-housing portion 10b is located above the cylinder head 1f.

On the lower surface of the bottom wall 10d of the storage box 10, the carburetor 2
4 and a single recess 10c for avoiding interference between the air control valve 25 and the air control valve 25 arranged in parallel with the recess 4c.
Are formed. As shown in FIG. 1, the interference avoiding concave portion 10 c is formed in a shape and volume that overlaps with the upper half of the carburetor 24 and forms an extra space with the carburetor 24 when viewed from the side of the vehicle. ing. In addition,
In the present embodiment, as shown in FIG. 2A, the above-described air cleaner 29, air hose 31, air control valve 25, air hose 32, and reed valve 26a constitute a secondary air supply device B.

The flow of air from the air cleaner 29 to the unit swing engine 1 and the flow of secondary air from the air cleaner 29 to the reed valve 26a are as follows. <Flow of Air from Air Cleaner 29 to Unit Swing Engine 1> The air introduced from the air cleaner 29 removes dust and the like from the inlet tube 28.
Is supplied to the carburetor 24. Here, the carburetor 24 mixes the fuel and air supplied from the fuel tank 20 described above, and supplies the air-fuel mixture into the cylinder head 1f of the unit swing engine 1 to drive the engine unit 1a, thereby driving the engine unit 1a. The power is transmitted to the rear wheel 21 by the power transmission mechanism, and is converted into a rotational force of the rear wheel 21.

<Air cleaner 29 to reed valve 26
flow of secondary air reaching a> On the other hand, the air filtered by the air cleaner 29 flows into the air control valve 25 via the air hose 31. The air that has passed through the air control valve 25 is supplied to the exhaust port 34 via the reed valve 26a. The air control valve 25 is provided with pipes 33a, 33 connected to a control pipe 25d.
3b, is connected to the intake pipe 27,
Normally, air is always supplied to the exhaust port.

However, when the pressure in the intake pipe 27 becomes a negative pressure higher than the set pressure of the valve due to abrupt accelerator full closing operation or the like during operation, the diaphragm in the valve bends and the valve closes, and the inflow pipe 25b and the outflow pipe 25b The tube 25c is shut off. As a result, after being filtered by the air cleaner 29, the air control valve 25, the air hose 32 and the reed valve 2
The air supplied to the exhaust pipe 35 via 6a is shut off.

In the scooter type vehicle provided with the above-described secondary air supply device B, an air control valve 25 for controlling the supply of secondary air in the secondary air supply device B is provided.
Is arranged at a position overlapping the carburetor 24 and the intake pipe 27 in a vehicle side view, so that the carburetor 24 and the air control valve 25 are connected to the storage box 1.
0 can be arranged in the interference avoiding concave portion 10c formed on the lower surface of the bottom wall 10d. Therefore, it is not necessary to form a recess for accommodating the air control valve 25 separately from the interference avoiding recess 10c.

Further, conventionally, the side of the intake pipe 27 is a dead space, but the dead space can be effectively utilized, and the air control valve 25 can be arranged as close to the unit swing engine 1 as possible. . Further, the length of the air hose 32 for guiding the secondary air from the air control valve 25 to the reed valve 26a provided on the cylinder head cover 1g of the cylinder 1c can be reduced as much as possible, and the arrangement route of the air hose 32 is simplified. it can.

Further, since the air cleaner for supplying the secondary air and the air cleaner for supplying the air to the carburetor 24 are also used, there is no need to provide a separate air cleaner, and therefore, compared to the conventional case. The arrangement of components, piping, etc. can be performed very easily,
The assembly work can be reduced, and the size and cost of the device can be reduced.

[0040]

According to the first to fourth aspects of the present invention, the air control valve for controlling the supply of the secondary air in the secondary air supply device is disposed at a position overlapping the carburetor and the intake pipe in a vehicle side view. So that it is possible to effectively use the space on the side of the intake pipe which has not been used conventionally,
Space efficiency can be improved.

Further, since the air control valve is provided at the upper part of the cylinder, the air control valve can be hardly exposed to a stepping stone or the like from the front wheel.

In addition to the above-mentioned common effects obtained by the inventions of claims 1 to 4, the following effects can be obtained by the inventions of the respective claims. According to the second aspect of the present invention, the single box recessed toward the inside of the storage box for avoiding interference with the carburetor and the air control valve is provided on the lower surface of the bottom wall of the storage box provided above the unit swing engine. Since the one interference avoiding concave portion is formed, even when the air control valve is arranged at a position overlapping the carburetor and the intake pipe in a vehicle side view, separately from the air control valve, There is no need to form a recess to avoid interference.

According to the third aspect of the present invention, since the air control valve is disposed at a height from the ground surface lower than the intake pipe, interference with the storage box is avoided. Therefore, the degree of freedom in design can be improved.

According to the fourth aspect of the present invention, by disposing the fuel tank below the front of the cylinder head, it is effective in preventing stepping stones and the like from the front wheels from colliding with the air control valve and the reed valve. is there.

[Brief description of the drawings]

FIG. 1 is a perspective side view of a scooter type vehicle provided with a secondary air supply device according to an embodiment of the present invention.

FIGS. 2A and 2B show a main part of the unit swing engine, wherein FIG. 2A is a partial side view, and FIG. 2B is an arrow view from the direction I shown in FIG.

FIG. 3 is a plan view of the unit swing engine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Unit swing engine 1c Cylinder 2 Body frame 10 Storage box 10c Interference avoiding recess 10d Lower surface of bottom wall 20 Fuel tank 24 Carburetor 25 Air control valve 27 Intake pipe B Secondary air supply device G Ground surface H Helmet

Claims (4)

[Claims] 1. An engine section comprising a cylinder inclined forward substantially horizontally, a cylinder head connected to an upper part of the cylinder, an intake pipe connected to the cylinder head, and a carburetor connected to the intake pipe.
A unit swing engine integrally connected to a power transmission unit that transmits the driving force of the engine unit to the rear wheels, and by supplying secondary air to exhaust gas derived from the unit swing engine. A secondary air supply device for a scooter type vehicle equipped with a unit swing engine provided with a secondary air supply device for purifying the exhaust gas, wherein the secondary air supply device controls the supply of the secondary air in the secondary air supply device. A secondary air supply device for a scooter-type vehicle, wherein an air control valve is disposed at a position overlapping the carburetor and the intake pipe in a side view of the vehicle. 2. The scooter-type vehicle includes a storage box capable of storing a helmet or the like above the unit swing engine, and a lower surface of a bottom wall of the storage box includes:
2. A single interference avoiding recess formed inwardly of the storage box for avoiding interference with the carburetor and the air control valve.
A secondary air supply device for a scooter-type vehicle according to any of the preceding claims. 3. The scooter-type vehicle according to claim 1, wherein the air control valve has a height from the ground surface lower than the intake pipe. Secondary air supply device. 4. The secondary air supply device for a scooter-type vehicle according to claim 1, wherein a fuel tank is disposed below and forward of said unit swing engine.