JPH0610134Y2 - Catalyst converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a catalytic converter, and more particularly to a catalytic converter made of metal.

(Prior Art) Among catalytic converters, there is one in which a catalyst carrier is made of metal as seen in Japanese Utility Model Publication No. 52-32753. This type is called a metal catalyst, and many studies have been made to put it into practical use because of its ease of manufacturing.

In such a case, the metal catalyst is made of a metal, and thus has a drawback of poor heat retention due to heat dissipation due to its thermal conductivity.

It is considered effective to interpose a heat insulating material between the metal catalyst and the casing against such a problem.

However, if the heat insulating material is simply interposed, the exhaust gas may blow through the heat insulating material without being purified. Further, the gas attack of the exhaust gas may cause the heat insulating material to be thermally deteriorated, which may further promote the blow-through of the exhaust gas.

Therefore, an object of the present invention is to provide a metal catalyst, that is, a catalytic converter that solves the above problems that occur when a heat insulating material is interposed between a metal catalyst carrier and a casing. .

(Means and Actions for Solving Problems) In order to achieve the above object, according to the present invention, in a catalytic converter in which a catalyst carrier housed in a casing is made of metal, an outer peripheral surface of the catalyst carrier is provided. A cylindrical holding plate is joined to accommodate the catalyst carrier, a space is provided between the outer peripheral surface of the holding plate and the inner peripheral surface of the casing, and the outer peripheral surface of the holding plate or the casing. Two annular protrusions are provided on the inner peripheral surface of the upstream end portion and the downstream end portion thereof, and a heat insulating material having thermal expansion characteristics is disposed between the two protrusions. At least one projection is provided on the holding plate.

With the above configuration, first, the heat insulation between the catalyst carrier and the casing keeps the catalyst carrier warm, and of the two protrusions, the protrusion located at the upstream end serves as a wall. The amount of exhaust gas entering the gap between the casing and the holding plate is narrowed down, and as a result, gas attack on the heat insulating material is reduced. Further, along with this, the possibility of exhaust gas blow-through is reduced. Moreover, because the insulation has adiabatic expansion properties,
Even if the temperature is high, the thermal expansion causes the catalyst carrier and the holding plate to be supported as a kind of floating.

Furthermore, the cylindrical holding plate itself prevents thermal deformation and thermal expansion of the catalyst carrier, and the protrusions provided on the holding plate increase the rigidity of the holding plate, further improving the function of the holding plate. I will let you. For this reason,
It is possible to effectively suppress deterioration of durability due to thermal deformation of the catalyst carrier.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows an exhaust system E of an automobile engine. The exhaust system E is composed of an exhaust manifold 1, an exhaust pipe 2, and a silencer 3 in this order from the engine body (not shown) side. The pipe 2 is provided with a catalytic converter 10 that purifies harmful components in the exhaust gas.

The catalytic converter 10 has a casing 12, as shown in FIG. The casing 12 is made of stainless steel and includes an inlet 12a and an outlet 12b,
The expansion chamber 12 is provided between the inlet 12a and the outlet 12b.
c is provided, and the catalyst carrier 14 is disposed in the expansion chamber 12c.

The catalyst carrier 14 here is the above-mentioned Japanese Utility Model Publication No. 52-3275.
Similar to the one disclosed in Japanese Patent Publication No. 3), it is formed by spirally winding a flat thin plate and a corrugated thin plate both formed from a stainless thin plate in a strip shape, and the catalyst carrier 14 has a flat thin plate. The catalyst (Pt, etc.) is supported by coating the front and back of the corrugated thin plate.

The catalyst carrier 14 has such an outer diameter H that it can form a space L between it and the inner peripheral surface 12 d of the casing 12, and the outer peripheral surface 14 a of the catalyst carrier 14 has a cylindrical holding plate 16. Is fixed by welding.

The holding plate 16 is provided with two beads 18 extending circumferentially around the catalyst carrier 14 at intervals in the direction of the axis l, that is, at the upstream end and the downstream end.
In the height dimension of 8, the apex is the inner peripheral surface 1 of the casing 12.
The size is such that a gap δ of about 1 mm can be formed between it and 2d. A heat insulating material 20 is interposed between the holding plate 16 and the casing 12 in a compressed state, and the heat insulating material 20 is held by the beads 18.

As the heat insulating material 16, an interram mat is adopted here. As is well known, the interrum mat is made by adhering leucite to a ceramic fiber, and the leucite (vermiculite) is composed of hydromagnesium silicate containing Al and Fe, and its volume is high at high temperature. About 6 ~
It has the property of expanding 20 times.

In such a structure, heat transfer from the catalyst carrier 14 to the casing 12 is suppressed by the heat insulating material 20, and the catalyst carrier 14 is kept warm. Therefore, exhaust gas can be sufficiently purified under a smooth catalytic reaction. Further, the exhaust gas passing through the interval L has its inlet narrowed by the upstream bead 18, so that the gas attack on the heat insulating material 20 is reduced, and accordingly, the exhaust gas is purified through the heat insulating material 20. The risk of being blown without is reduced. In addition, the catalyst carrier 14 is supported by the heat insulating material 20 as a kind of floating support, and the thermal expansion of the heat insulating material 20 ensures reliable floating support even at high temperatures. For this reason, vibration transmission from the catalyst carrier 14 to the casing 12 is also suppressed. Further, this embodiment has an advantage that the shape of the casing 12 need not be modified.

3 and subsequent drawings show other embodiments of the present invention.
The same elements as those of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. Only the characteristic portions will be described below.

FIG. 3 shows the second embodiment. In the present embodiment, the length dimension of the holding plate 16 is set to extend across the expansion chamber 12c of the casing 12, and the upstream end and the downstream end thereof are arranged. Is formed with a flange 30 extending outward in the radial direction. As a result, the holding plate 16 becomes the heat insulating material 20.
In addition to the holding function of the catalyst carrier 14, the catalyst carrier 14 also has a positioning function for the casing 12.

FIG. 4 shows a third embodiment. In this embodiment, the casing 12 is formed with two beads 40 that project inward in the radial direction, while the holding plate 16 is provided only at the downstream end thereof. A flange 42 is formed.

According to this embodiment, the upstream bead 40 and the flange 42
The heat insulating material 20 is held by and the catalyst carrier 14 is positioned by the cooperation of the downstream bead 40 and the flange 42.

(Effects of the Invention) As is clear from the above description, according to the present invention, the heat insulating material keeps the catalyst carrier warm, so that the exhaust gas can be sufficiently purified by the catalyst. Also,
It is possible to reduce the risk of the gas attack on the heat insulating material and the possibility that the exhaust gas will blow through the heat insulating material. Further, the vibration of the metal catalyst carrier can be prevented from being transmitted to the casing by a kind of floating support by the heat insulating material. In addition, it is possible to effectively suppress deterioration of durability due to thermal deformation of the catalyst carrier.

[Brief description of drawings]

FIG. 1 is a sectional view of a catalytic converter according to the first embodiment, FIG. 2 is an overall configuration diagram of an exhaust system of an engine, FIG. 3 is a sectional view of a catalytic converter according to a second embodiment, and FIG. It is sectional drawing of the catalytic converter which concerns on 3rd Example. DESCRIPTION OF SYMBOLS 10: Catalytic converter 12: Casing 12c: Enlarged chamber of casing 12d: Inner peripheral surface of casing 14: Catalyst carrier 14a: Outer peripheral surface of catalyst carrier 16: Holding plate 18, 40: Bead 20: Heat insulating material 30: Flange

Claims (1)

[Scope of utility model registration request] 1. A catalytic converter in which a catalyst carrier housed in a casing is made of metal, and a cylindrical holding plate is joined to an outer peripheral surface of the catalyst carrier so as to house the catalyst carrier. A gap is provided between the outer peripheral surface of the plate and the inner peripheral surface of the casing, and two annular protrusions are provided on the outer peripheral surface of the holding plate or the inner peripheral surface of the casing at the upstream end portion and the downstream end portion thereof. And a heat insulating material having a thermal expansion characteristic is disposed between the two protrusions, and at least one protrusion of the two protrusions is provided on the holding plate. .