JP2008180116A - Exhaust gas cleaning device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust gas cleaning device for an internal combustion engine equipped with novel structure capable of preventing melting damage in a catalytic device with no rising in the cost of a product. <P>SOLUTION: In this exhaust gas cleaning device C for an internal combustion engine, a catalyst metal carrier 10 is composed of a metal outer cylinder 11 constituting a portion of a flow passage of exhaust gas G generated in the internal combustion engine, and a core piece 12 partitioning the inside of the metal outer cylinder 11 by a partitioning wall along the longitudinal direction of the cylinder. The exhaust gas G from the internal combustion engine is cleaned by the catalytic device 1 composed of the catalyst metal carrier 10 having a catalyst-functional material 13 coated thereon. The catalytic device 1 forms a melting damage avoiding action part 15 within the range of an inflow side of the exhaust gas G, and the melting damage avoiding action part 15 is composed in a state of not having the catalyst-functional material 13 coated on the catalyst metal carrier 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an exhaust gas purifying device for an internal combustion engine, which is particularly suitable for application to a small motorcycle or the like, which is often used in a full rotation state during running.

Conventionally, it has been stipulated that a device for purifying exhaust gas has recently been stipulated for small motorcycles, which have been considered to have a lower environmental impact than automobiles, and development of devices suitable for them has been earnestly made. .
On the other hand, for motorcycles equipped with an engine with a total displacement of around 100 cc, for example, regardless of the case in Japan, depending on the region of use (country), legal speed and road environment may be full. There are often situations where the vehicle travels long in the throttle state.
Such a use situation is extremely severe for a catalyst device of an exhaust gas purification device, and in a severe case, the catalyst device is burned down, and a sufficient exhaust gas purification function cannot be exhibited, or There was a concern about the problem of lowering the running performance.

Specifically, the catalyst metal carrier that supports the catalyst functional material in the catalyst device has a core piece of, for example, a honeycomb shape or a curved plate inside the metal outer cylinder, and the catalyst on the surface of the metal outer cylinder and the core piece. Although the functional material is coated, it is also expected that this portion is exposed to a high temperature of the exhaust gas and is subjected to a heat load that melts particularly the core piece in the catalyst metal support.
By the way, the melt in this type of catalytic device is most likely to occur when the exhaust pipe connected to the catalytic device from the engine side is exposed to the highest temperature. As in the case of No. 75724 (prior art document 1), a heat-resistant measure is particularly taken on the exhaust gas introduction side.
However, in this type of product that has extremely strict cost requirements, it is difficult to take measures that cause such an increase in cost.
JP 2006-75724 A

  The present invention has been made in consideration of these various backgrounds, and is an exhaust gas purification system for an internal combustion engine having a novel configuration capable of preventing melting in a catalytic device without increasing the cost of the product. A device is proposed.

  The exhaust gas purifying device for an internal combustion engine according to claim 1 divides a metal outer cylinder constituting a part of a flow path of exhaust gas generated in the internal combustion engine, and a partition along the longitudinal direction of the cylinder. In the device for purifying the exhaust gas from the internal combustion engine by the catalyst device in which the catalyst metal carrier is configured by the core piece and the catalyst metal material is coated on the catalyst metal carrier, the catalyst device is provided on the inflow side of the exhaust gas. In the range, a melting avoidance action portion is formed, and this melting avoidance action portion is characterized in that the catalyst metal support is not coated with a catalyst functional material.

  In the exhaust gas purifying apparatus for an internal combustion engine according to claim 2, in addition to the above requirements, the length of the melting avoidance action portion is set to 5% to 30% of the longitudinal dimension of the catalyst metal carrier. Is a feature.

  The exhaust gas purifying device for an internal combustion engine according to claim 3 is characterized in that, in addition to the above requirements, the catalyst device is incorporated in a silencer unit attached to the internal combustion engine.

First, when exposed to the exhaust gas of an internal combustion engine, the catalytic function material functions in the catalyst device, and the catalytic function material itself exhibits a heat storage state. As a result, the core piece as the catalyst metal carrier carrying the catalyst functional material is brought into a heated state exceeding the melting limit, and is melted by receiving a physical impact such as exhaust gas pulsation. Once this smashing starts, the smashed catalyst metal carrier material is then heated by the flow of exhaust gas, further heating the surrounding materials, resulting in significant damage. It has been elucidated.
However, according to the first aspect of the present invention, in the portion where the heat load is the highest, since there is no catalytic functional material, a sufficient heat resistance effect can be achieved. Even in the catalytic action area provided in the stage, a situation in which the melting does not occur is obtained, and as a result, the durability and stable function of the catalytic device itself are ensured.

  Further, according to the second aspect of the invention, the melting avoidance action portion is set to an appropriate dimension setting range.

  Furthermore, according to the invention described in claim 3, by placing the catalyst device in the silencer unit, a more rational design is possible in an exhaust system device such as a motorcycle that requires a relatively compact design. It is.

  BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention includes an embodiment described below, and includes various improved embodiments based on this technical idea.

Hereinafter, the present invention will be specifically described based on illustrated embodiments.
First, reference numeral M in FIG. 1 represents a motorcycle as an example to which the exhaust gas purifying apparatus C for an internal combustion engine of the present invention is applied. In the middle of the exhaust gas G discharge path from the engine unit E of the motorcycle M, the catalyst device 1 that is a substantial main member of the exhaust gas purification device C for an internal combustion engine of the present invention is mounted. Specifically, the catalyst device 1 is provided in the silencer unit 2, and the position where the catalyst device 1 is provided is near the connection portion of the exhaust pipe 3 extending from the engine unit E.

The catalyst device 1 will be specifically described below. In this embodiment, in order to expect an effective action of the catalyst device 1, the catalyst device 1 is provided in two series in series, and is constituted by a primary catalyst unit 1A and a secondary catalyst unit 1B.
The specific embodiments of the present invention described below are particularly preferably provided in the primary catalyst unit 1A, but may be provided in the secondary catalyst unit 1B.
First, the catalyst device 1 uses a metal carrier for catalyst as a basic skeleton member, and this is constituted by, for example, a pipe-shaped metal outer cylinder 11 and a core piece 12 accommodated therein.
In the illustrated embodiment, for example, the core piece 12 is formed by bending a metal plate and fitting it into the metal outer cylinder 11 so that several spaces along the longitudinal direction of the cylinder are defined inside the metal outer cylinder 11. It is comprised as follows.

  By the way, this is the type that the applicant has already manufactured and sold under the trade name (registered trademark) of “Pipe S-Cat.” As shown in FIG. This is applied, and the configuration disclosed in Japanese Patent Application Laid-Open No. 2005-186027, Japanese Patent Application Laid-Open No. 2005-188474, etc. is applied. Of course, as the core piece 12 itself, as shown in FIG. 2B, a so-called honeycomb core piece 12 of a type in which a flute material integrated with a conventional flat metal liner is spirally wound is applied. You can also do it.

  The catalytic functional material 13 is coated on the surface of the core piece 12 and the inner peripheral surface of the metal outer cylinder 11 so as to function as the catalytic device 1. As a feature of the present invention, the catalyst device 1 is provided with a melting avoidance operating portion 15 on the exhaust gas introduction side, and this melting avoidance operating portion 15 is simply described without using a separate heat-resistant material or the like. It is configured as a region where the catalytic functional material 13 is not coated. Accordingly, the area where the catalytic functional material 13 is applied is displayed as the catalytic functional area 16.

The present invention is based on such a configuration, and when the exhaust gas G in the engine unit E reaches the catalyst device 1 through the exhaust pipe 3, first, the exhaust gas G is introduced into the melting avoidance operating unit 15. In this case, the absence of the catalytic function material 13 having a heat storage effect prevents the melting, and in that state, the catalyst function region 16 is reached and the nitrogen oxide component in the exhaust gas G is reached. It purifies environmentally hazardous compounds such as hydrocarbon components.
Of course, theoretically, in the catalytic function region 16, there is naturally a heat storage action by the catalytic function material 13, and there is a concern about melting of the catalyst metal carrier 10, but heat generation during the experiment is The situation that does not lead to melting has been confirmed. The reason for this is not necessarily elucidated, but the exhaust gas G flowing inside the catalyst device 1 is always in a pulsating state, and its physical influence is once introduced into the catalyst device 1. It is presumed that the rectification state is sometimes caused, and the shock applied to the core piece 12 or the like is reduced, or a certain temperature drop is caused.

[Other Examples]
The present invention is based on the embodiment described above as one basic technical idea, but the following modifications can be considered.
For example, as defined in claim 3, when the design of the exhaust system member of the motorcycle M or the like is made more compact, it is a preferred embodiment that the catalyst device 1 is provided in the silencer unit 2. When there is a sufficient installation space or when a catalytic function at a constant temperature or higher can always be expected, the catalyst device 1 can be installed inside the exhaust pipe 3 before the silencer unit 2.

  In addition, in the background description of the present invention in the present specification, the small motorcycle M and the like in which such a technical problem has occurred are illustrated, but of course, the same environmental load is necessarily generated in the small engine unit E. Instead, the present invention may be applied to an automobile having an engine unit E having a larger displacement.

It is explanatory drawing which shows the Example of the exhaust-gas purification apparatus for internal combustion engines of this invention combined with the application object. It is explanatory drawing containing a partially broken perspective view same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Catalytic apparatus 1A Primary catalyst unit 1B Secondary catalyst unit 10 Metal carrier for catalyst 11 Metal outer cylinder 12 Core piece 13 Catalytic functional material 15 Melting avoidance action part 16 Catalytic functional area 2 Silencer unit 3 Exhaust pipe C Exhaust gas for internal combustion engine Purifier E Engine unit M Motorcycle G Exhaust gas

Claims (3)

A catalyst metal carrier is constituted by a metal outer cylinder constituting a part of a flow path of exhaust gas generated in an internal combustion engine, and a core piece that divides the inside of the metal outer cylinder by a partition along the longitudinal direction of the cylinder. In an apparatus for purifying exhaust gas from an internal combustion engine by a catalyst device in which a catalytic functional material is coated on a metal carrier for use in
The catalyst device forms a melting avoidance action part in the exhaust gas inflow side range, and the melt avoidance action part is configured so that the catalytic metal material is not coated on the catalyst metal carrier. An exhaust gas purifying device for an internal combustion engine.   2. The exhaust gas purifying device for an internal combustion engine according to claim 1, wherein the length of the erosion avoiding action portion is set to 5% to 30% of the longitudinal dimension of the catalyst metal carrier.   The exhaust gas purification device for an internal combustion engine according to claim 1 or 2, wherein the catalyst device is incorporated in a silencer unit attached to the internal combustion engine.

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