JPS61283714A - Exhaust purifying device for motorcycle - Google Patents

Abstract

PURPOSE:To smooth the operation of a reed valve as well as to make a driver so as to be getting off without paying special consideration for its setup, by installing the reed valve in an empty space being formed between exhaust pipes dividedly installed in a car width direction at the front side of an internal- combustion engine. CONSTITUTION:A reed valve 14 is set up in an empty space to be formed between exhaust pipes 5 and 9 dividedly installed in a car width direction at the front side of an internal-combustion engine 3. When the engine 3 is driven, this reed valve 14 is is surely opened by suction pressure of a pressure wave in exhaust gas to be exhausted to these exhaust pipes 5 and 9 from a combustion chamber. With this constitution, secondary air is fed to the inside of each exhaust pipe smoothly, thus exhaust emission control takes place.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an exhaust purification device for a motorcycle that purifies exhaust gas discharged from a combustion chamber of an internal combustion engine.

(Prior art) Some motorcycles have a plurality of exhaust pipes connected to an internal combustion engine mounted on the vehicle body, which extend from the front side of the internal combustion engine downward and backward in a substantially parallel manner, and these exhaust pipes are equipped with reed valves. .

This reed valve opens using the negative pressure of the pressure wave of exhaust gas discharged from the combustion chamber of an internal combustion engine, supplies secondary air into the exhaust pipe, and uses this secondary air to burn the exhaust gas and oxidize it. promote and purify exhaust gas.

(Problem to be solved by the invention) In this way, the reed valve that supplies secondary air to the exhaust pipe operates by using the negative pressure of the pressure wave of the exhaust gas, so it At a remote location, the negative pressure of the pressure wave becomes small, and the reed valve may not open sufficiently, leading to insufficient suction of secondary air.

Therefore, it is preferable to place the reed valve in a location close to the combustion chamber of the internal combustion engine, but in this case, consideration should be given so that the reed valve does not interfere with the arrangement of other parts placed in the internal combustion engine layer. There is a need.

This invention has been made in view of the above circumstances, and is an exhaust purification device for a motorcycle that allows smooth operation of the reed valve that supplies secondary air to the exhaust pipe and does not require special consideration for the arrangement of the reed valve. is intended to provide.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a reed valve formed between the exhaust pipes separated in the vehicle width direction at the front side of the internal combustion engine. It is characterized by being placed in a space where

(Function) In this invention, when the internal combustion engine is operated, the reed valve is reliably opened by the negative pressure of the pressure wave of the exhaust gas discharged from the five combustion chambers to the exhaust pipe, and the secondary air is smoothly introduced into the exhaust pipe. supply This secondary air burns the exhaust gas in the exhaust pipe, promoting oxidation of the exhaust gas and purifying it.

(Example) Hereinafter, an example of the present invention will be described in detail based on the accompanying drawings.

In the figure, reference numeral l indicates a motorcycle, and a four-cylinder ■-type internal combustion engine 3 is mounted on a body frame 2 of the motorcycle l.

Each cylinder 4 on the front side of the V-type internal combustion engine 3 has an exhaust pipe 5.
is connected, and this exhaust pipe 5 is divided in the vehicle width direction and extends substantially parallel downward along the engine case 6 of the V-type internal combustion engine 3, and further bends downward to pass below the V-type internal combustion engine 3. It extends rearward and is connected to the exhaust manifold pipe 7.

Further, an exhaust pipe 9 is connected to each cylinder 8 on the rear side of the V-type internal combustion engine 3, and this exhaust pipe 9 is bent and extends downward, and is connected to an exhaust manifold pipe 7 located below. There is.

A muffler 10 is connected to the exhaust manifold pipe 7, and the muffler 1
A catalyst 11 is placed inside the cell with a mat 12 interposed therebetween. For example, a monolithic catalyst is used as the catalyst 11, and the exhaust gas is purified when it passes through a honeycomb-shaped gap.

A thermosensor 13 is placed close to the rear of the catalyst 11, and is configured to turn on a warning light when the temperature exceeds a predetermined value.

A space is formed at the lower front side of the V-type internal combustion engine 3 between a pair of exhaust pipes 5 that are separated in the vehicle width direction and arranged substantially parallel to each other, and a reed valve 14 is arranged in this space. . This reed valve 14 is opened by the negative pressure of the pressure wave caused by the discharge of exhaust gas from the V-type internal combustion engine 3, and supplies secondary air to the exhaust pipe 5 from the vicinity of the combustion chamber.

One end of each reed valve 14 is connected to the exhaust pipe 5 via a communication pipe 15, and the other end is connected to an air cut valve 16, respectively. Furthermore, the other end of the air cut valve 16 is connected to a connecting pipe 17. The air cut valve 16 closes during deceleration, the negative pressure in the exhaust pipe 5 rises, and the reed valve 14 opens wide to prevent excess air from flowing in.

The connecting pipe 17 is bent in any direction at the front central portion of the engine case 6, extends upward, and is connected to a secondary air cleaner 18.

The secondary air cleaner 18 is arranged above the V-type internal combustion engine 3 with its axial direction facing the vehicle width direction.
An air introduction pipe 19 is connected to the distal end of the air intake pipe 8 . This air introduction pipe 19 is bent, with its tip facing inward.

Further, the reed valve 14, the communication pipe 15, and the air cut valve 16 are covered by an under cowl 20.

Next, the operation of this embodiment will be explained.

When the exhaust holes of each cylinder 4, 8 open at a predetermined exhaust timing due to operation of the V-type internal combustion engine 3, high-pressure exhaust gas is intermittently discharged into the exhaust pipe 5.9.

This exhaust gas is collected in an exhaust manifold pipe 7, muffled by a muffler lO connected to the rear, and released into the atmosphere.

As the V-type internal combustion engine 3 operates, the exhaust ports of the cylinders 4 and 8 are intermittently opened and high-pressure exhaust gas is blown out, thereby generating pressure waves within the exhaust pipe s. During low speed rotation and medium speed rotation, the reed valve 14 opens due to negative pressure generated by pressure waves of exhaust gas discharged from the V-type internal combustion engine 3.

Therefore, air flows from the air introduction pipe 19 to the secondary air cleaner 1.
This secondary air is sucked into the exhaust pipe 5 through the connecting pipe 17, the air cut valve 16, and the reed valve 14.

With this secondary air, the exhaust gas discharged into the exhaust pipe 5 is combusted while it is in a high temperature state during low speed rotation and medium speed rotation, thereby oxidizing and purifying the exhaust gas.

Further, this exhaust gas is collected in an exhaust manifold pipe 7, and is purified by passing through a catalyst 11 disposed at the rear.

By the way, when the ■-type internal combustion engine 3 is decelerated, nonflammable gas is discharged and the negative pressure in the exhaust pipe 5 increases. Therefore, the air cut valve 16 is closed to restrict the introduction of air to prevent a large amount of air from being sucked in and causing an explosion.

This air cut valve 16 is arranged close to the reed valve 14, so that when the air cut valve 16 restricts the introduction of secondary air, air remaining in the pipe is not supplied.

Furthermore, during high-speed rotation, the negative pressure in the exhaust pipe 5 becomes high, making it difficult for the reed valve 14 to open. However, during high-speed rotation, combustion is performed well, and the amount of unburned gas discharged into the exhaust pipe 5 is reduced. Ru.

(Effects of the Invention) As described above, the reed valve that supplies secondary air to the exhaust pipe is located at the front side of the internal combustion engine, and the space is formed between the exhaust pipes that are separated in the width direction of the vehicle. Since the reed valve is located near the combustion chamber of the internal combustion engine,
It is reliably opened by the negative pressure of the exhaust gas pressure wave, allowing secondary air to be smoothly supplied into the exhaust pipe, and there is no need to ensure a special pace for arranging the reed valve.

[Brief explanation of drawings]

Figure 1 is a side view of a motorcycle to which this invention is applied;
The figure is a side view of the main part, and FIG. 3 is a front view of the main part. 2... Body frame 3... Internal combustion engine 4.8... Cylinder 5.9... Exhaust pipe lO... Muffler 11... Catalyst 14... Reed valve 16... Air cut valve 18...Secondary air cleaner

Claims (1)

[Claims] Multiple exhaust pipes connected to the internal combustion engine mounted on the car body,
Exhaust purification for motorcycles equipped with a reed valve that divides in the width direction of the vehicle and extends approximately parallel to the front side of the internal combustion engine, passes below and rearward, and supplies secondary air to this exhaust pipe to promote oxidation of exhaust gas. The exhaust purification device for a motorcycle, wherein the reed valve is disposed in a space formed between exhaust pipes separated in the vehicle width direction on the front side of the internal combustion engine.