JPH05319353A - Exhaust gas purifying device for scooter - Google Patents

Abstract

PURPOSE:To avoid the breakdown of a secondary air leading pipe effectively even in the case where a clearance is small between the road surface and the vicinity of an exhaust muffler base end, to which a secondary air leading pipe is connected. CONSTITUTION:In a power unit 13 for scooter, in which a cylinder 17 is provided forward and horizontally and an exhaust muffler 25 is extended from the lower surface of the cylinder 17 to the road surface side and suspension members 18, 19 are positioned in both sides of the lower part of the cylinder 17, a secondary air leading pipe 28 is connected to the vicinity of the exhaust muffler 25 base end. A check valve 29 is connected to the other end of this secondary air leading pipe 28 to form an exhaust gas purifying device for scooter, and in this exhaust gas purifying device for scooter, the secondary air leading pipe 28 is connected to a position upper than the lowest part 25a of the exhaust muffler 25, and the secondary air leading pipe 18 is arranged between the cylinder 17 and the suspension members 18, 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying apparatus for a scooter which introduces secondary air into exhaust gas to completely combust unburned components, and more particularly to the position of the secondary air supply pipe.

[0002]

2. Description of the Related Art A secondary air introduction type exhaust gas purifying apparatus for introducing secondary air from the outside into an exhaust muffler and completely burning harmful unburned components contained in the exhaust gas is
It is generally used in vehicles such as motorcycles. This exhaust gas purifying apparatus is configured by connecting a secondary air introducing pipe near the base end of the exhaust muffler and providing a check valve at the other end of the secondary air introducing pipe.

Since positive pressure and negative pressure are repeatedly generated in the exhaust muffler due to the pulsation of the exhaust gas, when the negative pressure is generated in the exhaust muffler, the check valve is opened and the secondary air flows in the exhaust muffler. Is introduced, and oxygen in the secondary air re-ignites unburned components in the high-temperature exhaust gas to completely burn it. Further, when the pressure in the exhaust muffler becomes positive, the check valve is closed to prevent the outflow of exhaust gas.

[0004]

By the way, in many scooters of recent years, a large-capacity helmet storage chamber is provided below a seat, and in such scooters, an engine cylinder has a bottom portion of the helmet storage chamber. In order to avoid interference with the cylinder, the cylinder is installed almost horizontally toward the front. The exhaust muffler attached to the cylinder has a shape that extends below the cylinder (on the road surface side) and curves rearward.

When the above-mentioned secondary air introduction type exhaust gas purifying device is installed in such a scooter, generally, a branch pipe is provided near the base end of the exhaust muffler, and a heat resistant rubber hose or the like is used for this branch pipe. The secondary air introducing pipe is connected, and a check valve is provided at the other end of the secondary air introducing pipe. The check valve is arranged in the upper part of the engine or the like.

However, as described above, the exhaust muffler extends from the lower surface of the cylinder to the road surface side, and the clearance between the base end of the exhaust muffler and the road surface is small. The secondary air introduction pipe connected near the base end portion is likely to be hit by obstacles on the road surface, flying stones from the front wheels, and the like, which may damage the secondary air introduction pipe.

The present invention has been made in order to solve this problem. Even when the clearance between the exhaust muffler base end portion to which the secondary air introduction pipe is connected and the road surface is small,
An object of the present invention is to provide an exhaust gas purification device for a scooter that can effectively avoid damage to the secondary air introduction pipe.

[0008]

In order to achieve the above object, in an exhaust gas purifying apparatus for a scooter according to the present invention, a cylinder is installed substantially horizontally toward the front, and an exhaust muffler is provided from a lower surface of the cylinder to a road surface side. A secondary air introduction pipe connected to the vicinity of the exhaust muffler base end of the scooter power unit where suspension members are located on both sides of the lower part of the cylinder, and a check valve is connected to the other end of the secondary air introduction pipe. In the exhaust gas purifying apparatus for the connected scooter, the secondary air introduction pipe is connected to a position above the lowest portion of the exhaust muffler, and the secondary air introduction pipe is piped between the cylinder and the suspension member. It is a feature.

[0009]

When the exhaust gas purifying device for a scooter is constructed in this way, the secondary air introduction pipe is protected from obstacles and flying stones on the road surface by the exhaust muffler and the suspension member, and damage is avoided.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a left side view of a scooter to which the present invention is applied. This scooter 1 has a general vehicle body layout, and its vehicle body frame 2 has a head pipe 5 for supporting the front wheels 3 and the front forks 4, a down tube 6 extending rearward and downward from the head pipe 5, and a down tube 6 It is composed of a pair of left and right rear frames 7 extending from the rear end to the upper rear. Rear frame 7
A helmet storage room 9 capable of storing the helmet 8 is installed on the top of the helmet storage room 9.
Is mounted so that it can be opened and closed. The vehicle body frame 2 and the helmet storage chamber 9 as described above are covered with a frame cover 11 made of synthetic resin or the like, and the appearance of the scooter 1 is adjusted.

In the power unit 13 of the scooter 1, a swing case 15 extending rearward is integrally connected to the left side surface of the crankcase 14 of the engine, and a rear wheel 16 is rotatably supported on the rear right side surface of the swing case 15. The power transmission devices are built in the swing case 15, and the cylinder 17 of the engine faces forward from the front of the crankcase 14 in order to avoid interference with the bottom of the helmet storage chamber 9. It is installed so that it extends almost horizontally.

FIG. 2 is a view taken along the line II-II of FIG. Figure 1
As shown in FIG. 2, the crankcase 14 is integrally formed with a pair of left and right suspension arms 18, 18 extending to both sides of the lower portion of the cylinder 17, and these suspension arms 18, 18 are respectively provided with suspension links 19. , 19 via pivot shafts 21 mounted on the body frame 2. The suspension arms 18, 18 and the suspension links 19, 19 are collectively referred to as suspension members. In addition, the rear portion of the swing case 15 and the rear frame 7
A shock absorber 22 is connected between and. For this reason,
The power unit 13 is rotatable around the pivot shaft 21 and the pivot shaft 23 together with the rear wheel 16, and the buffer device 22 buffers the rotation of the power unit 13. As shown in FIG. 2, a forced air cooling fan device 24 that cools the cylinder 17 is installed on the right side surface of the crankcase 14.

The exhaust muffler 25 attached to the cylinder 17 has a shape extending from the lower surface of the cylinder 17 to the ground side and curving rearward. This exhaust muffler 25
It moves integrally with the rotation of the power unit 13 and the rear wheel 16.

Next, the exhaust gas purifying apparatus according to the present invention will be described. In the vicinity of the base end of the exhaust muffler 25,
A branch pipe 27 as shown in FIG. 2 is provided, and a secondary air introducing pipe 28 made of a heat resistant rubber hose is connected to the branch pipe 27. The branch pipe 27 is provided above the lowest portion 25a of the exhaust muffler 25. Further, the secondary air introducing pipe 28 is installed between the cylinder 17 and the suspension member (suspension arms 18, 18 and suspension links 19, 19) and installed on the top of the cylinder 17.
9 is connected.

For example, a small air cleaner 30 is installed above the rear frame 7, and the air cleaner 30 and the check valve 29 are connected by a rubber hose 31.
Further, a rubber hose 32 having an open end is connected to the air cleaner 30.

When the engine is operated, positive pressure and negative pressure due to the pulsation of exhaust gas are alternately generated in the exhaust muffler 25. The check valve 29 is provided from the air cleaner 30 to the exhaust muffler 2.
Since only the air flow to 5 is passed, the external air is sucked into the air cleaner 30 to remove dust only when the inside of the exhaust muffler 25 has a negative pressure, and is introduced into the exhaust muffler 25 as secondary air. The secondary air introduced into the exhaust muffler 25 is
Oxygen in the secondary air mixed with the high-temperature exhaust gas re-ignites the unburned components contained in the exhaust gas and completely burns them to purify the exhaust gas.

Since the secondary air introduction pipe 28 is located above the lowest portion 25a of the exhaust muffler 25, the exhaust muffler 25
It protects you from obstacles on the road. Further, flying stones or the like that the front wheels 3 jump up while the scooter 1 is running are shielded by the left suspension arm 18 and the suspension link 19, and there is no possibility of directly hitting the secondary air introduction pipe 28. Therefore, as in the scooter 1 of the present embodiment, the exhaust muffler 25
Even if the clearance between the base end portion and the road surface is small, it is possible to effectively avoid damage to the secondary air introduction pipe 28.

[0018]

As described above, in the exhaust gas purifying apparatus for a scooter according to the present invention, the cylinder is installed substantially horizontally toward the front, and the exhaust muffler extends from the lower surface of the cylinder to the road surface side. The secondary air introducing pipe is connected near the exhaust muffler base end of the scooter power unit in which the suspension members are located on both sides of the lower part of In the gas purifier, the secondary air introducing pipe is connected to a position above the lowest portion of the exhaust muffler, and the secondary air introducing pipe is piped between the cylinder and the suspension member. is there.

Therefore, the secondary air introduction pipe is protected from obstacles on the road surface by the exhaust muffler, and is also protected from flying stones from the front wheels by the suspension member. As a result, damage to the secondary air introduction pipe can be effectively avoided.

[Brief description of drawings]

FIG. 1 is a left side view of a scooter to which the present invention has been applied.

FIG. 2 is a view showing an embodiment of the present invention as seen from the direction of arrows II-II in FIG.

[Explanation of symbols]

 1 Scooter 2 Body Frame 13 Power Unit 14 Crankcase 15 Swingcase 16 Rear Wheel 17 Cylinder 18 Suspension Arm as a Suspension Member 19 Suspension Link 25 as a Suspension Member 25 Exhaust Muffler 25a Lower Exhaust Muffler 27 Branch Pipe 28 Secondary Air Inlet Pipe 29 Check valve 30 Air cleaner 31, 32 Rubber hose

Claims (1)

[Claims] 1. An exhaust muffler base of a power unit for a scooter in which a cylinder is installed substantially horizontally toward the front, an exhaust muffler extends from a lower surface of the cylinder to a road surface side, and suspension members are located on both sides of a lower portion of the cylinder. In the exhaust gas purifying device for a scooter, in which a secondary air introduction pipe is connected near the end and a check valve is connected to the other end of the secondary air introduction pipe,
An exhaust gas purifying apparatus for a scooter, characterized in that the secondary air introducing pipe is connected to a position above the lowest portion of the exhaust muffler, and the secondary air introducing pipe is provided between the cylinder and the suspension member.