JPH0754642A - Exhaust device of engine - Google Patents

Abstract

PURPOSE:To efficiently purify harmful component in exhaust gas by quickly starting catalytic reaction even just after engine is started. CONSTITUTION:In an exhaust device provided with an exhaust pipe 11 to be connected to the exhaust port 10 of an engine and an exhaust muffler connected on the downstream side of the exhaust pipe 11, wherein a main catalyst member 14 is provided in the exhaust pipe 11, an auxiliary catalyst member 18 protruded in the exhaust port 10 is provided on the exhaust port connecting part of the exhaust pipe 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine exhaust system in which exhaust gas is purified by a catalyst member installed inside.

[0002]

2. Description of the Related Art A general exhaust system used in a motorcycle or the like comprises an exhaust pipe connected to an exhaust port of an engine and an exhaust muffler connected to the rear of the exhaust pipe. A catalyst member is often installed inside such an exhaust device, and when exhaust gas flowing in the exhaust device comes into contact with the catalyst member, harmful components such as HC and CO contained in the exhaust gas. Undergoes catalytic reaction and is oxidized. Therefore, these harmful components are purified, and the pollution of exhaust gas is reduced.

As described above, in order to purify the exhaust gas by causing the harmful components in the exhaust gas to undergo a catalytic reaction, the catalyst member itself needs to have a sufficiently high temperature. Therefore, the catalyst member is installed in the exhaust pipe close to the exhaust port so that the catalyst member can be heated by the high-temperature exhaust gas discharged from the exhaust port of the engine. Further, in this way, the high-temperature exhaust gas discharged from the exhaust port can immediately contact the catalyst member, so that the catalytic reaction is started quickly and the exhaust gas can be purified efficiently.

[0004]

However, immediately after the engine is started, for example, since the temperature of the catalyst member is room temperature, it takes some time for the catalyst member to reach a high temperature due to the heat of the exhaust gas. Then, during this period, the efficient catalytic reaction is not promoted, and there is a concern that some harmful components may be directly discharged to the outside.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to quickly start the catalytic reaction immediately after the engine is started, and it is possible to effectively purify harmful components in the exhaust gas. An object is to provide an exhaust system for an engine.

[0006]

In order to achieve the above object, an engine exhaust system according to the present invention comprises an exhaust pipe connected to an exhaust port of the engine and an exhaust muffler connected to a downstream side of the exhaust pipe. Prepare,
In an exhaust system of an engine in which a main catalyst member is provided in an exhaust pipe, an auxiliary catalyst member protruding into the exhaust port is provided at an exhaust port connecting portion of the exhaust pipe.

Further, the main catalyst member is installed in the exhaust pipe so as to be continuous to the downstream side of the auxiliary catalyst member.

Further, the auxiliary catalyst member is fixed to the exhaust port connecting portion of the exhaust pipe and protrudes into the exhaust pipe, and is fixed to the cylindrical sleeve portion carrying the catalyst component and the inner peripheral portion of the sleeve portion. And a plate portion along with the flow of the exhaust gas and carrying the catalyst component.

[0009]

According to the exhaust system of the engine having the above structure,
Since the auxiliary catalyst member protruding into the exhaust port can come into contact with the exhaust gas at the highest temperature, even if the auxiliary catalyst member is at room temperature immediately after the engine is started, the auxiliary catalyst member will be exposed to the hot exhaust gas to assist the exhaust gas. The catalyst member quickly rises in temperature to quickly start a catalytic reaction to purify exhaust gas.

By the reaction with such an auxiliary catalyst member,
The exhaust gas further rises in temperature and continues to contact the main catalyst member. Therefore, the temperature of the main catalyst member is quickly raised, and the catalytic reaction by the main catalyst member is started in a very short time, so that the exhaust gas is further purified. Therefore, the harmful components in the exhaust gas are effectively purified even immediately after the engine is started.

Further, since the main catalyst member is installed in the exhaust pipe so as to be continuous to the downstream side of the auxiliary catalyst member, the temperature of the exhaust gas whose temperature has risen due to the reaction with the auxiliary catalyst member as described above decreases. The main catalyst member can be immediately contacted without causing it. Therefore, the temperature rise time of the main catalyst member is further shortened, and the start of the catalytic reaction by the main catalyst member is accelerated.

Further, a cylindrical sleeve portion fixed to the exhaust port connecting portion of the exhaust pipe and protruding into the exhaust pipe and carrying a catalyst component, and an inner peripheral portion of the sleeve portion are fixed to the exhaust gas flow. Since the auxiliary catalyst member is configured to include the plate portion on which the catalyst component is supported along with the above, the effective contact area of the auxiliary catalyst member becomes very large. This promotes efficient exhaust gas purification.

[0013]

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 motorcycle equipped with an exhaust system according to the present invention. This motorcycle 1
An engine 2 is mounted on a substantially central portion of a vehicle body, and exhaust devices 5 and 6 connected to the cylinder assemblies 3 and 4 of the engine 2 extend rearward along both side surfaces of the vehicle body. Silencers 7 and 8 are connected to the rear ends of these exhaust devices 5 and 6, respectively.

FIG. 2 is a left side view of the exhaust device 5 provided on the left side of the motorcycle 1 body, and FIG. 3 is a III-II of FIG.
It is sectional drawing which follows the I line. The exhaust device 5 includes an exhaust pipe 11 connected to an exhaust port 10 of the engine 2 (cylinder assembly 3) and an exhaust muffler 12 connected to the downstream side of the exhaust pipe 11. A tail pipe 13 is connected to the downstream side of the exhaust muffler 12, and the silencer 7 is connected to the rear end of the tail pipe 13.

As shown in FIG. 3, the exhaust pipe 1
1 has a structure in which a pair of left and right pipe halves 11L and 11R are joined by welding or the like in the central portion. Further, the exhaust muffler 12 has a similar structure and is joined to the exhaust pipe 11 by welding or the like.

A main catalyst member 14 is provided in the exhaust pipe 11. The main catalyst member 14 is, for example, in the form of a plate having catalyst components carried on the front and back surfaces, and fixing pieces 14a and 14b provided on both edges thereof are joined to the pipe half body 11R side. The main catalyst member 14 is provided with ribs 14c for reinforcement and surface area increase, and a plurality of holes 14d for allowing exhaust gas to flow to the front and back of the main catalyst member 14.

FIG. 4 is an enlarged view of the IV portion of FIG. 2, showing an embodiment of the present invention. Further, FIG. 5 is a VV arrow view of FIG.

At the outer end of the exhaust port 10, a flange insertion portion 10a having a slightly large diameter is formed. On the other hand, a bellows pipe 16 is fixed to the exhaust port connecting portion of the exhaust pipe 11 via a spacer 15.
The mounting washer 17 fixed to the tip of the exhaust port 10 is fixed to the exhaust port 10 with a bolt or the like not shown. The bellows pipe 16 has a function of absorbing thermal expansion of the exhaust pipe 11 and absorbing a vibration from the engine 2.

An auxiliary catalyst member 18 projecting into the exhaust port 10 is provided at the exhaust port connecting portion of the exhaust pipe 11.
Is provided. As shown in FIG. 6, the auxiliary catalyst member 18 includes a cylindrical sleeve portion 19 and a plate portion 20 fixed to the inner peripheral portion of the sleeve portion 19.

The sleeve portion 19 is formed with a flange 19a at one end and an enlarged diameter portion 19b at the other end. Further, the plate portion 20 has a shape along the flow of exhaust gas and is provided with a large number of holes 20a. Fixed by etc. The catalyst component is carried on the inner peripheral surface of the sleeve portion 19 and the front and back surfaces of the plate portion 20 by thermal spraying or the like.

As shown in FIG. 4, the expanded diameter portion 19b of the sleeve portion 19 is fixed to the inner peripheral portion of the bellows pipe 16 on the downstream side,
The flange 19a of the sleeve portion 19 projects upstream from the mounting washer 17. Therefore, the mounting washer 17
Is fixed to the outlet of the exhaust port 10, the flange 19a of the sleeve portion 19 projects into the exhaust port 10 and is inserted into the flange insertion portion 10a of the exhaust port 10 via the gasket 21. Here, the main catalyst member 14 installed in the exhaust pipe 11 is arranged to be continuous to the downstream side of the auxiliary catalyst member 18.

The structure of the exhaust device 6 provided on the right side of the motorcycle 1 is also the same as that of the exhaust device 5.

When the engine 2 operates, the exhaust port 10
The exhaust gas discharged from the first contact the auxiliary catalyst member 18, and then the main catalyst member 14. At that time, harmful components such as HC and CO contained in the exhaust gas undergo a catalytic reaction to be oxidized and the exhaust gas is purified.

Exhaust device 5 (6) constructed as described above
According to the above, the auxiliary catalyst member 1 protruding into the exhaust port 10
Since the exhaust gas 8 can come into contact with the exhaust gas in the highest temperature, even if the auxiliary catalyst member 18 is at the normal temperature immediately after the engine 2 is started, the auxiliary catalyst member 18 is exposed to the high temperature exhaust gas and the auxiliary catalyst member 18 quickly becomes high in temperature. And quickly start the catalytic reaction to purify the exhaust gas.

Due to such reaction with the auxiliary catalyst member 18, the temperature of the exhaust gas further rises and continues to contact the main catalyst member 14. Therefore, the temperature of the main catalyst member 14 also rises rapidly, and the catalytic reaction by the main catalyst member 14 is started in a very short time, and the exhaust gas is further purified. Therefore,
Even immediately after the engine 2 is started, the harmful components in the exhaust gas are effectively purified.

The main catalyst member 14 is the auxiliary catalyst member 18
Since it is installed in the exhaust pipe 11 so as to be continuous to the downstream side of the exhaust gas, the exhaust gas whose temperature has risen due to the reaction with the auxiliary catalyst member 18 as described above immediately enters the main catalyst member 14 without causing a temperature drop. Can contact. Therefore, the temperature rise time of the main catalyst member 14 is further shortened, and the start of the catalytic reaction by the main catalyst member 14 is accelerated.

Further, the auxiliary catalyst member 18 is composed of the cylindrical sleeve portion 19 carrying the catalyst component and the plate portion 20 with the catalyst component fixed to the inner peripheral portion of the sleeve portion 19. The effective contact area of the catalyst member 18 is very large. This promotes efficient exhaust gas purification.

Moreover, the auxiliary catalyst member 1 having such a structure
8 can be manufactured at a very low cost, and at the same time, can be easily retrofitted to a ready-made exhaust device, and thus can greatly contribute to reduction of exhaust gas pollution in a motorcycle or the like.

In some cases, the plate portion 20 of the auxiliary catalyst member 18 may be omitted (see FIG. 7), or the main catalyst member 14 and the auxiliary catalyst member 18 may be integrally connected.

[0031]

As described above, the engine exhaust system according to the present invention comprises the exhaust pipe connected to the exhaust port of the engine and the exhaust muffler connected to the downstream side of the exhaust pipe. In an exhaust system for an engine in which a main catalyst member is provided, an auxiliary catalyst member protruding into the exhaust port is provided at an exhaust port connecting portion of an exhaust pipe.

According to this structure, the auxiliary catalyst member protruding into the exhaust port can come into contact with the exhaust gas in the highest temperature state, so that even if the engine is just started and the auxiliary catalyst member is in the normal temperature state, the high temperature is high. When exposed to such exhaust gas, the auxiliary catalyst member rapidly rises in temperature and promptly initiates a catalytic reaction to purify the exhaust gas.

By the reaction with such an auxiliary catalyst member,
The exhaust gas further rises in temperature and continues to contact the main catalyst member. Therefore, the temperature of the main catalyst member is quickly raised, and the catalytic reaction by the main catalyst member is started in a very short time, so that the exhaust gas is further purified. Therefore, the harmful components in the exhaust gas are effectively purified even immediately after the engine is started.

Further, since the main catalyst member is installed in the exhaust pipe so as to be continuous to the downstream side of the auxiliary catalyst member, the temperature of the exhaust gas whose temperature has risen due to the reaction with the auxiliary catalyst member causes a temperature drop. It is possible to contact the main catalyst member immediately without using. Therefore, the temperature rise time of the main catalyst member is further shortened, and the start of the catalytic reaction by the main catalyst member is accelerated.

Further, the auxiliary catalyst member is fixed to the exhaust port connecting portion of the exhaust pipe and protrudes into the exhaust pipe, and is fixed to the cylindrical sleeve portion carrying the catalyst component and the inner peripheral portion of the sleeve portion. Therefore, the effective contact area of the auxiliary catalyst member becomes very wide because it is configured to include the plate portion on which the catalyst component is carried along with the flow of the exhaust gas. This promotes efficient exhaust gas purification.

[Brief description of drawings]

FIG. 1 is a left side view of a motorcycle provided with an exhaust device according to the present invention.

FIG. 2 is a left side view of the exhaust device.

3 is a cross-sectional view of the exhaust device taken along line III-III in FIG.

FIG. 4 is an enlarged view of an IV portion of FIG. 2, showing an embodiment of the present invention.

5 is a V-V arrow view of FIG. 4.

FIG. 6 is a perspective view of an auxiliary catalyst member.

FIG. 7 is a perspective view of an auxiliary catalyst member showing another embodiment of the present invention.

[Explanation of symbols]

 1 Motorcycle 2 Engine 5,6 Exhaust Device 10 Exhaust Port 11 Exhaust Pipe 12 Exhaust Muffler 14 Main Catalyst Member 18 Auxiliary Catalyst Member 19 Sleeve Part 20 Plate Part

Claims (3)

[Claims] 1. An exhaust pipe for an engine, comprising: an exhaust pipe connected to an exhaust port of the engine; and an exhaust muffler connected to a downstream side of the exhaust pipe, wherein an exhaust pipe of the engine is provided with a main catalyst member. An exhaust system for an engine, characterized in that an auxiliary catalyst member projecting into the exhaust port is provided at the exhaust port connecting part. 2. The exhaust system for an engine according to claim 1, wherein the main catalyst member is installed in the exhaust pipe so as to be continuous to the downstream side of the auxiliary catalyst member. 3. The auxiliary catalyst member is fixed to an exhaust port connecting portion of an exhaust pipe and protrudes into the exhaust pipe, and is fixed to a cylindrical sleeve portion carrying a catalyst component and an inner peripheral portion of the sleeve portion. The exhaust device for an engine according to claim 1, wherein the exhaust device is configured to include a plate portion on which a catalyst component is carried and which follows the flow of exhaust gas.