JP2837382B2 - Engine exhaust purification device - Google Patents

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 applied to a vehicle engine, particularly to a motorcycle engine.

[0002]

2. Description of the Related Art As an exhaust gas purifying device applied to a motorcycle engine, an exhaust gas purifying device is generally installed in a muffler which is continuously attached to an exhaust pipe.

[0003] As a prior art having a structure in which an exhaust purification device is installed in a muffler, for example, Japanese Patent Laid-Open No. 7-3 is disclosed.
No. 05624.

The muffler described in this publication has a cylindrical body main portion connected to a tapered tapered portion, and a perforated baffle tube is arranged at the center of the body main portion. The main body space is divided into a plurality of exhaust expansion spaces by a partition plate to form a muffler, and exhaust is purified to the front of this muffler, that is, to a tapered tip at a predetermined distance from the front end of the baffle tube. A catalyst plate is installed.

The catalyst plate is formed by spraying ceramic or cermet or the like on the surface of a plate base made of a steel plate or a stainless steel material to form a sprayed layer, and the sprayed layer comprises a catalyst solution and a catalyst carrier. The slurry is applied and dried and fired to fix the catalyst on the surface of the sprayed layer.

In order to enhance the purification performance of the exhaust gas as much as possible, the catalyst plate is formed to have a curved cross-sectional shape such as an S-shape to increase the contact area with the exhaust gas, In order to assemble to the muffler body, push it into the tapered end and bolt the catalyst plate rear end to the muffler body.
It is fastened detachably using nuts.

[0007]

As described above, when the catalyst plate is assembled to the muffler body, the catalyst plate is detachably fastened to the tapered end of the muffler body by using bolts and nuts alone. In such a case, there is direct contact between the catalyst plate and the inner surface of the tapered tip, so that heat is locally transmitted from the catalyst plate, which rises in temperature due to the reaction heat of the catalyst, to the tapered tip, causing a temperature difference in the entire muffler body. Is generated.

Further, since there is a difference between the contact between the catalyst plate and the inner surface of the tapered tip portion and the gap formed between the catalyst plate and the inner surface of the tapered tip portion, a difference occurs in the flow resistance of exhaust gas at each portion of the catalyst plate. .

In the operation of mounting the catalyst plate to the muffler body, the catalyst plate is inserted from the rear end opening of the muffler body and fastened by bolts through nuts provided in the catalyst plate and fastening holes provided in the tapered tip portion. In addition, it is necessary to align a fastening hole provided near the middle of the muffler body with a nut provided on the catalyst plate.

Further, in forming the catalyst on the catalyst plate, in order to prevent the catalyst-forming substance (chemical) from adhering to the threaded portion of the nut attached to the base of the catalyst plate, it is necessary to carry out the operation in advance. Pretreatment such as screwing the external thread is required.

[0011]

In order to solve the above-mentioned problems, the present invention provides a muffler body in which a catalyst member is cantilevered by a muffler component, and a muffler component is provided.
This makes it easier to assemble the catalyst member to the muffler body.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a baffle tube front part.
The catalyst members are extended and connected to the
Around the baffle tube and the inside of the muffler body
Arrange and support a heat shield tube forming a gap, and
The front edge of the probe is lightly pressed on the inner surface of the muffler body .

It is preferable that the catalyst member is cantilevered and connected to the baffle tube so that the space for disposing the catalyst member in the muffler body is set so as to extend from the main body portion in front of the muffler to the tapered tip portion.

Further, it is effective that the catalyst member is formed in a perforated tubular shape and connected and connected concentrically with the baffle tube.

Preferably, the rear end of the catalyst member is fitted to the front end of the baffle tube, and the two are welded together.

Further, in order to cut off the direct transfer of heat from the exhaust gas to the muffler body, a heat shield tube which forms a small gap with the inner surface of the muffler body is provided around the catalyst member and the baffle tube which are connected in an extended manner. The heat insulating effect is enhanced by disposing and supporting the front end of the heat shield tube to the inner surface of the tapered tip portion.

The catalyst member configured as described above is
A unit for the muffler body that is unitized with the constituent members
Attaching a well-known single silencer to the muffler body
It can be easily done in the same way.

[0018]

Embodiments will be described with reference to the drawings.
In FIG. 1, an engine (not shown) is connected via an exhaust pipe A.
The muffler body 1 of the muffler connected to the main body 3 has a configuration in which a tapered tapered portion 2 is connected to a cylindrical body main portion 3, and a muffler 4 is provided in the body main portion 3. .
This silencer 4 has a baffle tube 5 having a vent hole in the center of the main body of the body, and a partition plate 6 for lining the inside of the main body 3.
It is a well-known configuration in which a plurality of exhaust expansion cavities 7 are partitioned, and exhaust gas is sequentially introduced into and out of each of the cavities 7 through the baffle tube 5 to reduce the exhaust pressure and also exhibit a sound-muffling effect. .

In the present invention, the front portion of the baffle tube 5 constituting the muffler 4, a catalyst member 8 bonded continuously provided to the extension form without contacting the muffler body 1 is coupled continuously provided in the extension like this A heat shield tube 13 forming a small gap with the inner surface of the muffler body 1 is disposed around the catalyst member 8 and the baffle tube 5, and the front end of the heat shield tube 13 is lightly pressed to the inner surface of the muffler body 1. ing.

The heat shield tube 13 in this embodiment is
Divided into forward heat shield tube 13a and the rear heat shield tube 13b, as shown in FIG. 3, rear heat shield tube 13b
Is sandwiched and supported between two partition plates 6 located at an intermediate portion of the baffle tube 5, and the rear end of the tube is welded to the front surface of the corresponding partition plate 6 by welding (all-around welding) a.
The front edge of the tube is fitted into the outer peripheral portion forming the rearward tubular portion of the corresponding partition plate 6, and the rear edge of the partition plate 6 is welded (all-around welding) to the rear heat shield tube 13b.

The front heat shield tube 13a has a cone-shaped partition plate 6a fitted to the joint between the catalyst member 8 and the baffle tube 5 inserted into the tube to support the tube middle part from inside. , The rear heat shield tube 1
The inner edge of the partition plate 6a is welded to the catalyst member 8 at the front part of the baffle tube 5 by welding (total circumference welding) c, and the outer peripheral edge of the partition plate 6a. The middle part of the front heat shield tube 13a is welded (plug welded) at a plurality of places (preferably about three places) in the circumferential direction, and the rear edge of the front heat shield tube 13a is located in front of the corresponding partition plate 6. It is welded to the side surface (full circumference welding) e.

As described above, since the components of the muffler 4 and the catalyst member 8 including the heat shield tube 13 are unitized, the unitized member is attached to the muffler body 1 when the muffler body 1 is assembled. The mounting flange 10 inserted and fixed to the rear end of the baffle tube 1 is fastened to the mounting bracket 11 inside the muffler body 1 using bolts 12. This embodiment is applied to the muffler body 1 in which the body main part 3 of the muffler body 1 to be applied is tapered so as to be slightly expanded rearward. In this state, the front end edge of the front heat shield tube 13a is lightly press-fitted into the inner surface of the tapered tip portion 2 to maintain a lightly pressed state and to be stable, and formed between the heat shield tube 13 and the muffler body 1. This prevents the exhaust gas from directly flowing into the gap and exerts a heat insulating effect.

[0023]

The present invention is embodied in the form described above and has the following effects.

A catalyst member is connected to and extended from the front of the baffle tube, and a heat shield tube forming a small gap with the inner surface of the muffler body is arranged and supported around the catalyst member and the baffle tube. Since the front end of the tube is lightly pressed to the inner surface of the muffler body, the small gap formed between the muffler body and the heat shield tube functions as an insulating gap, and there is no direct contact of exhaust with the inner surface of the muffler body. The temperature rise of the body is suppressed, and the temperature of the entire muffler body is equalized in a low temperature state. In addition, the muffler constituting member and the catalyst member including the heat shield tube can be made into a unit, and the assembling to the muffler body can be easily performed by attaching a well-known single muffler to the muffler body.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing an embodiment of an exhaust gas purifying apparatus for an engine to which the present invention is applied.

FIG. 2 is a cross-sectional view of a unitized muffler component member and a catalyst member in FIG.

FIG. 3 is a partial cross-sectional view of a main part showing a joining relationship between a heat shield tube and related components.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Muffler body 2 Taper tip part 3 Body main part 4 Muffler 5 Baffle tube 6 Partition plate 8 Catalyst member 9 Weld joint 13 Heat shield tube

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F01N 3/28 F01N 1/08 F01N 3/24

Claims (1)

(57) [Claims] A catalyst member is connected to and extended from a front portion of a baffle tube, and a heat shield tube which forms a small gap with an inner surface of a muffler body is disposed and supported around the catalyst member and the baffle tube. Exhaust gas purification system for engines with the front end of the heat shield tube lightly pressed against the inner surface of the muffler body.