JPH088244Y2 - Catalytic converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of Invention] (Field of Industrial Use) The present invention relates to a catalytic converter for purifying exhaust gas, which is provided in, for example, an exhaust system of an engine of an automobile.

(Prior Art) For example, some automobiles are equipped with a catalytic converter 1 as shown in FIG. 3 in order to purify harmful components in exhaust gas such as unburned hydrocarbons.

That is, the catalytic converter 1 is composed of the converter container 2
Inside, the two catalysts 3 and 4 on the front stage side and the rear stage side are coaxially arranged. Then, as shown by an arrow A, the exhaust gas is caused to flow from one end side to the other end side in the axial direction, and the exhaust gas is sequentially passed through the catalysts 3 and 4. Further, the catalytic converter 1 uses the thermal energy of the exhaust gas, etc.
4 is heated and activated. And catalytic converter 1
Uses the activated catalysts 3 and 4 to remove harmful components such as unburned hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NO _x ) in the exhaust gas, and then exhaust the exhaust gas. Let

Further, catalyst holding layers (hereinafter, referred to as holding layers) 5 and 6 are formed in the catalytic converter 1. This holding layer 5,
6 is formed so as to be sandwiched between the inner peripheral surface of the converter container 2 and the outer peripheral surfaces of the two catalysts 3 and 4, respectively. Further, the holding layers 5 and 6 are made of a metal mesh such as steel wool. The holding layers 5 and 6 cover the outer surfaces of the catalysts 3 and 4, and the catalysts 3,
4 is held at a predetermined position inside the converter container 2.

Here, reference numerals 7 and 8 in FIG. 3 denote holding layers 5 and 6, respectively.
Is a ring-shaped seal member that is disposed inside the catalyst and extends in the circumferential direction of the catalysts 3 and 4, and seals between the converter container 2 and the catalysts 3 and 4.

(Problems to be Solved by the Invention) In the catalytic converter 1 as described above, a large amount of heat is radiated from the inside of the converter container 2 to the outside. There was a problem that it took a lot of time to activate.

An object of the present invention is to provide a catalytic converter capable of activating the entire catalyst in a short time.

[Constitution of device]

(Means and Actions for Solving the Problem) In order to achieve the above-mentioned object, the present invention arranges a catalyst in a converter container and accommodates a front-stage catalyst and a rear-stage catalyst coaxially in the converter container. In addition, a catalyst holding layer made of a heat insulating ceramic material having a flow groove through which exhaust gas flows is provided between the pre-stage side catalyst and the converter container.

By doing so, the present invention increases the temperature of the adiabatic ceramic material by the heat energy of the exhaust gas flowing through the flow groove of the catalyst holding layer, and also transfers the heat from the front-stage catalyst which is heated by the heat energy of the exhaust gas. Can be suppressed. Therefore, the front-stage catalyst is activated in a short time. Since the latter-stage catalyst is coaxially arranged, it is possible to purify the unpurified exhaust gas that has flowed through the flow groove.

(Embodiment) An essential part of an embodiment of the present invention will be described below with reference to FIGS. 1 and 2. The same parts as those described in the section of the prior art are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 1 shows an embodiment of the present invention. In the figure, reference numeral 3 denotes a pre-stage side catalyst (hereinafter referred to as a catalyst) arranged on the pre-stage side of the converter container 2. This catalyst 3 is of a monolith type and is formed into a cylindrical shape. The catalyst 3 is coaxially arranged inside the converter container 2 which is also cylindrical. Further, the catalyst 3 causes the exhaust gas flowing into the converter container 2 and flowing in the axial direction to flow in from the front surface 3a thereof. Then, the catalyst 3 allows the exhaust gas to flow in the axial direction inside thereof,
It is made to flow from 3b toward the post-stage catalyst 4 not shown.

Further, on the outside of the catalyst 3, a foamed ceramic (interlam mat (trade name)) 11 as a heat insulating ceramic material is provided. The foam ceramic 11 has excellent heat insulating properties and is formed into a rectangular plate shape. And
The foamed ceramic 11 has a widthwise dimension set substantially equal to the axial dimension of the catalyst 3, and a longitudinal dimension set substantially equal to the circumferential dimension of the catalyst 3.

Further, the foamed ceramic 11 has a plurality of linear flow grooves 12, which are arranged in parallel in the width direction, on the inner surface thereof.
The foamed ceramic 11 has the flow grooves 12 ... Arranged at substantially equal intervals over substantially the entire length in the longitudinal direction. Then, the foamed ceramic 11 is bent inward with the portion where the flow grooves 12 are located as a fold. Then, the foamed ceramic 11 covers the catalyst 3 in such a manner that the surface on the side where the flow grooves 12 are provided faces the outer peripheral surface 3c of the catalyst 3 and is bent while being wound around.

Further, as shown in FIG. 2, the foamed ceramic 11 is in close contact with the outer peripheral surface 3c of the catalyst 3 and the inner peripheral surface of the converter container 2, and the flow grooves 12 ... An opening is formed around the periphery of 3a and the rear surface 3b. The foam ceramic 11 is fixed to the catalyst 3 and the converter container 2, and holds the catalyst 3 inside the converter container 2. The foam ceramic 11 forms a holding layer 13 between the catalyst 3 and the converter container 2. Here, the foam ceramic 11 is heated and expands. Further, the catalyst 3 is omitted in FIG.

That is, in the catalytic converter 14 provided with the foam ceramic 11 as described above, the exhaust gas flowing into the converter container 2 is passed through the flow groove 12 between the catalyst 3 and the foam ceramic 11.
The catalyst 3 from the front side 3a side. Then, the exhaust gas is caused to flow through the flow grooves 12, and is made to flow from the rear surface 3b side of the catalyst 3 toward the rear side catalyst (not shown) side.

Further, the catalytic converter 14 heats the ceramic foam 11 with the thermal energy of the exhaust gas flowing through the flow grooves 12. Further, the catalytic converter 14 greatly reduces the transfer of heat from the catalyst 3 or the like heated by the passing exhaust gas to the converter container 2 due to the foamed ceramic 11. Therefore, heat dissipation from the converter container 2 to the outside can be prevented, and the temperature of the catalyst 3 can be efficiently raised. Therefore,
It is possible to sufficiently activate the catalyst 3 in a short time at the time of cold start or the like.

Here, in this embodiment, since the flow grooves 12 ... Are formed only on the outer peripheral portion of the front catalyst 3 and the flow grooves 12 are not formed on the rear catalyst (not shown) side, the flow grooves 12 are not formed. The exhaust gas that has passed through does not flow out of the converter container 2 in an unpurified state.

Incidentally, the holding layer on the catalyst side of the latter stage may be made of foamed ceramic in which the flow grooves 12 are not formed, or may be made of a metal mesh.

Further, in the present embodiment, the flow grooves 12 are formed so as to be parallel to the axial direction of the catalyst 3, but the present invention is not limited to this, and the direction of the flow grooves may be, for example, that of the catalyst 3. It may be formed along the circumferential direction.

Further, in the present embodiment, a monolith type catalyst is adopted for explanation, but other types of catalyst may be adopted.

[Effect of device]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, a front-side catalyst and a rear-side catalyst are coaxially arranged and housed in a converter container, and a flow groove through which exhaust gas flows between the front-side catalyst and the converter container. A catalyst holding layer made of a heat-insulating ceramic material is provided. Therefore, it is possible to raise the temperature of the heat insulating ceramic material by the heat energy of the exhaust gas flowing through the flow groove of the catalyst holding layer, and also suppress the transfer of heat from the upstream catalyst which has been raised by the heat energy of the exhaust gas. . Therefore, the front-stage catalyst is activated in a short time. In addition, since the latter stage catalyst is arranged coaxially,
It becomes possible to purify the unpurified exhaust gas that has flowed through the flow groove.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention.
FIG. 1 is a perspective view showing a main part in a partially disassembled state, FIG. 2 is a vertical sectional front view showing a converter container and foam ceramic, and FIG.
The figure is a longitudinal sectional view showing a conventional example. 2 ... Converter container, 3 ... Pre-stage side catalyst, 11 ... Foamed ceramic (insulating ceramic material), 12 ... Flow groove, 13 ...
… Retaining layer, 14… Catalytic converter.

Front page continuation (72) Inventor Takeo Kume 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (56) References JP 61-89916 (JP, A) Shoukai 62-143015 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. An adiabatic ceramic in which a pre-stage catalyst and a post-stage catalyst are coaxially arranged and accommodated in a converter container, and a circulation groove through which exhaust gas flows is provided between the pre-stage catalyst and the converter container. A catalytic converter comprising a catalyst holding layer made of material.