JP2000045761A - Catalytic converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalytic converter by which an inner peripheral cylinder wall is rapidly heated by the exhaust gas of high temperature introduced to a catalyst support so that the catalyst support can rapidly reaches the reaction temperature, and the exhaust gas can be clarified. SOLUTION: A honeycomb monolithic catalyst support 16 comprising a holding member 13 on its outer periphery and the packings 14, 15 on its front and rear parts, is installed in a cylindrical catalyst case 12 having an exhaust gas inlet 10 and an exhaust gas outlet 11. The catalyst case 12 is provided with a flange 18 mounted on the outer periphery of the exhaust gas inlet 10 and connected to an exhaust manifold 17. The catalyst case 12 comprises a space part 23 having an opening 21 on the flange 18 side and a connecting wall 22 between an outer peripheral cylinder 19 and an inner peripheral cylinder 20 on the opposite side, so that the double tubular structure consisting of the outer peripheral cylinder 19 and the inner peripheral cylinder 20 is formed. A flange 24 connected to an exhaust pipe not shown in Fig., is mounted on the outer periphery of the exhaust gas outlet 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalytic converter mounted on, for example, a vehicle exhaust system.

[0002]

2. Description of the Related Art FIG. 2 shows an example of this type of catalytic converter. As shown in the figure, this catalytic converter is connected to an exhaust manifold 1 of the engine.
A catalyst carrier 5 is accommodated in a catalyst case 4 having an exhaust gas inlet 2 connected to the outlet side of the catalyst and an exhaust gas outlet 3 connected to an exhaust pipe. By interposing the cushion material 6,
The catalyst carrier 5 is held in the catalyst case 4 and at the same time, damage and the like are prevented. Further, packings 7 and 8 are inserted before and after the catalyst carrier 5. A protector 9 is held on the outer periphery of the catalyst case 4 by fixing bolts 11 to a support portion 10 provided on the catalyst case 4 to protect the catalyst case 4 and to shield the heat of the high heat radiated from the catalyst case 4. ing.

[0003] With this configuration, the exhaust gas of the engine that has passed through the exhaust manifold 1 is guided from the exhaust gas inlet 2 into the catalyst case 4, and the exhaust gas is passed through the catalyst carrier 5. Purify carbon oxides, nitrogen oxides, etc. to make them harmless and exhaust gas outlet 3
To the exhaust pipe.

However, there are actually the following technical problems.

[0005]

That is, in the above-described conventional catalytic converter, since the catalyst case is made of cast iron and made relatively thick, high-temperature exhaust gas is introduced into the catalyst carrier. However, since it takes time for the heat to be taken by the catalyst case and the catalyst carrier to reach the reaction temperature, unburned gas is released from the exhaust pipe during that time.

Also, since high temperature is radiated along the wall of the catalyst case, it is necessary to install a protector on the outer periphery of the catalyst case to protect the temperature and protect the catalyst case. There was a problem that sound was emitted along the wall.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and provides a space between an outer peripheral tube and an inner peripheral tube of a catalyst case to form a cast iron catalyst case that comes into contact with a catalyst carrier. By reducing the wall thickness of the inner peripheral cylinder, the inner peripheral cylinder wall is quickly heated by the high-temperature exhaust gas introduced into the catalyst carrier, and the catalyst carrier can quickly reach the reaction temperature, and the exhaust gas is reduced. It is an object of the present invention to provide a catalytic converter that can be purified and that prevents heat and sound from being transmitted by a space portion, thereby reducing heat and sound radiation from a catalyst case.

[0008]

In order to achieve the above object, a catalytic converter according to the present invention accommodates a catalyst carrier in a catalyst case having an exhaust gas inlet and an exhaust gas outlet, and discharges the engine exhaust gas. In a catalytic converter for purifying by passing through a catalyst carrier, a space portion is provided in the catalyst case to form a double tube structure having an outer peripheral tube and an inner peripheral tube.

According to the above construction, by providing a space between the outer cylinder and the inner cylinder of the catalyst case, the thickness of the wall of the inner cylinder made of cast iron that comes into contact with the catalyst carrier can be reduced. As a result, the inner peripheral wall is quickly heated by the high-temperature exhaust gas introduced into the catalyst carrier, the catalyst carrier can quickly reach the reaction temperature, and the exhaust gas can be purified. In addition, it is possible to provide a catalytic converter that can prevent heat and sound from being transmitted by the space portion and reduce heat and sound radiation from the catalyst case.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view of the catalytic converter of the present invention.

As shown in FIG. 1, a holding member 13 is provided on the outer periphery of a cylindrical catalyst case 12 having an exhaust gas inlet 10 and an exhaust gas outlet 11, and a back and forth packing 1 is provided.
A honeycomb-shaped catalyst carrier 16 made of a monolith provided with 4, 15 is housed therein.

The catalyst case 12 has a flange 18 provided on the outer periphery of the exhaust gas inlet 10 and connected to an exhaust manifold 17. And the catalyst case 12
An opening 21 is provided on the flange 18 side, and a connecting wall 22 between the outer cylinder 19 and the inner cylinder 20 is provided on the opposite side so as to form a double pipe structure composed of the outer cylinder 19 and the inner cylinder 20. It has a space 23 having the same. A flange 24 to which an exhaust pipe (not shown) is connected is provided on the outer periphery of the exhaust gas outlet 11.

The thickness of the inner peripheral cylinder 20 is desirably set to, for example, about 3 mm in order to accelerate the temperature rise of the inner peripheral cylinder 20, and the space 23 is required in order to prevent heat insulation and noise.
Is desirably about 8 to 10 mm. In the above configuration, high-temperature exhaust gas discharged from the engine passes through the exhaust manifold 17, enters the honeycomb-shaped catalyst carrier 16 from the exhaust gas inlet 10, and the inner peripheral cylinder 20 is heated together with the catalyst carrier 16. Since the wall thickness of the inner peripheral cylinder 20 becomes thin (about 3 mm), the heating rate can be increased, whereby the catalyst carrier 16 reaches the reaction temperature quickly, and the exhaust gas is purified by the catalyst carrier 16. Purified gas is discharged from the exhaust gas outlet 11 to the outside via the exhaust pipe. At this time, since the space 23 is provided between the outer cylinder 19 and the inner cylinder 20, there is an effect that heat insulation and soundproofing can be achieved.

[0014]

In the above arrangement, high-temperature exhaust gas discharged from the engine passes through the exhaust manifold, enters the honeycomb-shaped catalyst carrier from the exhaust gas inlet, and the inner peripheral cylinder is heated together with the catalyst carrier. The heating speed can be increased because the wall thickness of the inner peripheral cylinder is reduced,
The catalyst carrier quickly reaches the reaction temperature, whereby the exhaust gas is purified by the catalyst carrier, and the purified gas is discharged from the exhaust gas outlet to the outside via the exhaust pipe. At this time, since a space is provided between the outer cylinder and the inner cylinder, there is an effect that heat insulation and soundproofing can be achieved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a catalytic converter according to the present invention.

FIG. 2 is a cross-sectional view of a conventional catalytic converter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Exhaust gas inlet 11 Exhaust gas outlet 12 Catalyst case 16 Catalyst carrier 19 Outer cylinder 20 Inner cylinder 23 Space

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) // F02B 77/11 F02B 77/11 D (72) Inventor Katsunori Bonshihara 3 Nakamachidai, Tsuzuki-ku, Yokohama-shi, Kanagawa No.12-3, Tokyo Foki Co., Ltd. F term (reference) 3G004 AA01 BA01 BA06 DA14 EA05 3G091 AA02 AB01 BA02 BA03 BA04 BA39 FA02 FA04 FB02 FC07 GA06 HA03 HA27 HA28

Claims (1)

[Claims] 1. A catalytic converter for accommodating a catalyst carrier in a catalyst case having an exhaust gas inlet and an exhaust gas outlet and purifying the catalyst by passing exhaust gas from an engine through the catalyst carrier. A catalytic converter having a double-pipe structure having an outer cylinder and an inner cylinder.