JPH09242532A - Catalyst device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst device, which can efficiently perform the catalytic reaction at the time of restarting an engine after the engine is stopped for a short time. SOLUTION: A cylindrical body 6 for raising heat capacity, of which thickness is larger than that of a metal foil of a metal carrier 2, is provided inside of the metal carrier 2 of a metal catalyst device 5. Since the cylindrical body 6 is made of the metal material and held in the condition that the cylindrical body 6 is insulated from an outer cylinder of the metal carrier 2, even in the case where an engine is stopped for a short time, a sudden lowering of the catalyst temperature is not generated, and the catalytic reaction immediately after restarting the engine is efficiently performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst device for purifying exhaust gas, in which a metal block for improving heat capacity is mounted inside a catalyst.

[0002]

2. Description of the Related Art Conventionally, exhaust gas from automobiles contains various harmful components (CO, HC, etc.). Therefore, a catalyst is used to reduce the harmful components to a certain level. The catalyst is mounted in the exhaust system of the engine, for example, directly below the exhaust manifold of the engine or in the middle of the exhaust pipe connected to the exhaust manifold.
The catalyst is housed and held in a catalyst case interposed in the exhaust system.

As a catalyst for purifying exhaust gas, a ceramic catalyst in which an active component is carried on a honeycomb ceramic carrier formed of ceramic, or a metal in which an active component is carried on a honeycomb metal carrier formed of a metal foil is used. There is a catalyst.

Comparing the above-mentioned ceramic catalyst and metal catalyst with the same purifying ability, the metal catalyst is easier to make smaller because the metal foil is thinner, and further, the metal foil is thinner and has better thermal conductivity, so the catalyst is better. It has the advantage of being activated quickly.

As a catalytic converter, the actual converter 62
There is one disclosed in Japanese Patent Publication No. 143015. The catalyst disclosed in this publication is obtained by filling a cell in the outer peripheral portion of a monolith carrier with a porous ceramic having a thermal expansion coefficient larger than that of the carrier, and supporting a catalyst metal on the monolith carrier filled with the ceramic. is there.

Further, as a muffler, a full-scale shokai 60-124
There is one disclosed in Japanese Patent No. 523. The silencer disclosed in this publication is provided with a metal foil heat storage plate having a large number of minute vent holes in a chamber on the exhaust gas inflow side.

[0007]

However, since the metal catalyst has good thermal conductivity of the material, when the engine is stopped, the temperature of the catalyst lowers faster than that of the ceramic catalyst, and the engine is stopped for a short time. After that, it is restarted, and the catalyst purification capability immediately after that is inferior to the ceramic catalyst.

If the temperature of the metal catalyst drops quickly, hydrocarbons (H
C) and carbon monoxide (CO) will increase rapidly. With this, it is difficult to meet the regulation value in the exhaust gas operation mode under the regulations of foreign countries, for example, North America.

Of course, when the engine is stopped for a long time and then restarted until the temperature of the ceramic catalyst is sufficiently lowered, the catalyst cleaning ability after the engine is started is the same for both the metal catalyst and the ceramic catalyst.

In the catalytic converter disclosed in Japanese Utility Model Laid-Open No. 62-143015, since the porous ceramic is provided in the cell at the outer peripheral portion of the monolith carrier,
Since the porous ceramic is not insulated from the outer peripheral portion, it is difficult to reliably suppress the temperature decrease.

Further, in the muffler disclosed in Japanese Utility Model Laid-Open No. 60-124523, since the metal foil heat storage plate is provided so as to face the exhaust gas flow, this plate prevents the exhaust gas flow resistance. Therefore, the exhaust efficiency may decrease.

The present invention has been made to solve the above-mentioned problems, and a metal block is integrally provided inside the honeycomb carrier of the catalyst to increase the heat capacity, and the engine is stopped for a short time and then restarted. Thus, it is an object of the present invention to provide a catalyst device that avoids a decrease in catalyst purification capacity immediately after restarting and efficiently performs a purification action.

[0013]

According to the first aspect of the present invention,
It is characterized in that a metal lump for increasing the heat capacity of the catalyst is integrally provided in a honeycomb carrier of the catalyst arranged downstream of the exhaust manifold. In this way, a metal mass for increasing the heat capacity is integrally provided in the honeycomb carrier of the catalyst, and the metal mass is kept heat-insulated from the outer cylinder of the honeycomb body to increase the heat capacity of the catalyst, and once the engine is stopped, The temperature of the activated catalyst should not drop sharply.

According to a second aspect of the present invention, the metal block is a plate-shaped member thicker than the metal foil forming the honeycomb carrier. In this way, the metal lump is formed of a plate-shaped material thicker than the metal foil forming the honeycomb carrier, thereby increasing the heat capacity and preventing the temperature of the catalyst from immediately decreasing after the engine is stopped.

According to a third aspect of the present invention, the metal block is concentrically provided in the honeycomb carrier. In this way, the metal lumps are concentrically arranged in the honeycomb carrier, thereby increasing the heat capacity and preventing the temperature of the catalyst from rapidly decreasing after the engine is stopped.

The invention of claim 4 is characterized in that the metal block is provided in a honeycomb carrier in a spiral shape. Thus, the metal lumps are arranged in a spiral shape in the honeycomb carrier, thereby increasing the heat capacity and preventing the temperature of the catalyst from rapidly decreasing after the engine is stopped.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention grasped from the description of claim 1, as shown in FIG. 1, a metal catalyst 2 arranged downstream of an exhaust manifold is concentrically formed with a metal in a metal carrier 2. The plate body 3 for increasing the heat capacity of the catalyst 1 is integrally arranged.

In the present invention grasped from the description of claim 2, as shown in FIG. 1, the metal lump is a plate body 3 thicker than the metal foil constituting the metal carrier 2.

In the present invention grasped from the third aspect, as shown in FIG. 2, the cylindrical body 6 is concentrically provided in the metal carrier 2.

In the present invention understood from the description of claim 4, as shown in FIG. 3, the plate member 8 is provided in the metal carrier 2 in a spiral shape.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a first embodiment of the present invention will be described with reference to FIG. In the figure, reference numeral 1 is a catalyst device provided in an exhaust pipe (not shown) which is an exhaust system of an automobile engine, that is, a metal catalyst device. The metal catalyst device 1 is arranged and held in a container (not shown) interposed in the exhaust pipe.

In this metal catalyst device 1, a plate body 3 which is a metal mass is arranged inside a honeycomb-shaped metal carrier 2 made of a metal foil, and an active component (noble metal) is carried on the metal carrier 2. It was made to form. Since the plate body 3 is mounted in order to increase the heat capacity of the metal carrier 2 of the metal catalyst device 1, the plate body 3 is insulated from the outer cylinder 4 and arranged concentrically in the center of the cross section of the metal carrier 2. .

The plate 3 is several times to several tens times thicker than the metal foil forming the metal carrier 2. The metal carrier 2 is formed by alternately stacking or winding metal flat plates and corrugated plates.

Next, the operation of the first embodiment will be described. In this first embodiment, a metal plate 3 is provided inside a metal carrier 2.
Are arranged concentrically in a state where they are insulated from the outer cylinder 4 of the metal carrier 2, so that the heat capacity of the exhaust gas is increased by the plate body 3, and the temperature of the once activated metal catalyst 1 is increased. The rate of decline is extended.

As a result, if the engine is stopped for a short time, the temperature at which the metal catalyst device 1 is activated can be sufficiently maintained. Therefore, when the engine is restarted after being stopped for a short period of time, it is possible to avoid a decrease in the catalytic purifying action and efficiently perform the catalytic reaction.

Next, a second embodiment of the present invention will be described with reference to FIG. 2 by attaching the same symbols to the same members as in FIG. In the metal catalyst device 5 of the second embodiment, a honeycomb-shaped metal carrier 2 made of metal is coaxially mounted with a cylindrical body 6 which is a metal mass, and the metal carrier 2 is further provided with an active component (noble metal). It is formed by carrying.

Since the cylindrical body 6 is mounted to increase the heat capacity of the metal carrier 2 of the metal catalyst device 1,
The outer casing 4 is insulated from the heat and is arranged in the center of the cross section of the metal carrier 2. The plate thickness of this cylindrical body 6 is also several to several tens of times thicker than the metal foil constituting the metal carrier 2.

The mounting of the cylindrical body 6 on the metal carrier 2 will be described. First, a flat plate made of metal and a corrugated plate are wound in a spiral shape to form the inner metal carrier 2a serving as the center.
Next, the cylindrical body 6 is press-fitted concentrically with the outer peripheral portion of the inner metal carrier 2a. The plate member and the inner metal carrier 2a may be integrally formed by winding the plate member around the outer peripheral portion of the inner metal carrier 2a without press-fitting the cylindrical body 6.

Further, a flat plate and a corrugated plate are spirally wound around the outer periphery of the cylindrical body 6 to form an outer metal carrier 2b having an appropriate thickness in the radial direction, and finally, the outer metal carrier 2b is formed. The outer cylinder 4 made of metal is fitted to the outer peripheral portion to integrally form the cylindrical body 6 and the metal carrier 2.

By repeating the winding of the metal flat plate and the corrugated plate and the press-fitting of the cylindrical body 6 in this manner, the cylindrical body 6
It is also possible to form the metal catalyst device 5 in which a plurality of metal catalysts are arranged concentrically inside the metal carrier 2. Although the cylindrical body 6 is arranged concentrically with the metal carrier 2, the heat capacity is increased,
If the exhaust gas flows efficiently, it is not always necessary to arrange them concentrically.

Inner metal carrier 2a and outer metal carrier 2b
Is formed by winding a metal flat plate and a corrugated plate in a spiral shape, but without doing so, the flat plate and the corrugated plate are alternately laminated to form the inner metal carrier 2a and the outer metal carrier 2b.
May be formed.

On the other hand, a cylindrical body 6 having an outer metal carrier 2b (a donut shape) having a hole in the center thereof and having the inner metal carrier 2a mounted in the hole of the center of the outer metal carrier 2b is formed. The cylindrical body 6 and the outer metal carrier 2b may be integrally formed by press-fitting. Also in this case, the outer metal carrier 2b and the inner metal carrier 2a are formed by winding a metal flat plate and a corrugated plate, or by alternately stacking them.

Since the metal catalyst device formed from the doughnut-shaped one as described above requires shaping, the cylindrical body 6 is press-fitted into the outer peripheral portion of the inner metal carrier 2a described above, and the cylindrical body 6 is further pressed. It requires a little more time to manufacture than the case where the outer metal carrier 2b is formed by spirally winding a flat plate and a corrugated plate on the outer peripheral part of the.

Although the cylindrical body 6 is mounted on the metal carrier 2 as a metal block, the metal block may have a rectangular tube shape. Further, it may be a columnar shape or a prismatic shape, but in this case, if the diameter is increased, it may affect the exhaust gas efficiency, so that it is formed in an appropriate shape.

Next, the operation of the second embodiment will be described. In the second embodiment, a metal cylindrical body 6 is provided inside a metal carrier 2.
Are arranged concentrically in a state in which they are insulated from the outer cylinder 4 of the metal carrier 2. Therefore, the heat capacity of the metal catalyst device is increased by the cylindrical body 6, and the once activated metal catalyst 1 The rate of temperature decrease is avoided. Thus, if the engine is stopped for a short time, the temperature at which the metal catalyst device 5 is activated can be maintained. Therefore, if the engine is restarted after being stopped for a short time, an efficient catalytic reaction can be performed.

Next, a third embodiment of the present invention will be described with reference to FIG. 3 for the same members as those in FIG. In the metal catalyst device 7 of the third embodiment, a flat plate and a corrugated plate made of metal and a plate material 8 which is a metal block are wound together in a spiral shape, and further, an active component (noble metal) is carried on the metal carrier 2. It was formed.

Further, the plate material 8 is several to several tens times thicker than the metal foil forming the metal carrier 2, as in the first and second embodiments. The operation of the third embodiment is substantially the same as that of the second embodiment, and will be omitted.

Further, the metal carrier 2 was formed by alternately laminating flat plates and corrugated plates made of metal or winding them in a spiral shape. It depends on the shape of the metal lump (plate, cylinder, plate) provided in the.

That is, when the outer shape of the metal mass and the cross-sectional shape of the outer cylinder 4 located at the outermost periphery of the metal catalyst device 1 are significantly different, for example, when the metal mass is triangular and the outer cylinder 4 is circular, The metal carrier 2 is preferably formed by laminating a flat plate and a corrugated plate.

When the outer shape of the metal mass and the cross-sectional shape of the outer cylinder 4 are similar, for example, when the metal mass is octagonal and the outer cylinder 4 is circular, the flat plate and the corrugated plate are wound in a spiral shape. By doing so, the metal lump and the outer cylinder 4 can be formed in similar shapes. At that time, using a corrugated plate, if it is wound so as to be in contact with the outer peripheral portion of the metal block, the metal block and the rolled plate are compared to the case where the flat plate is wound around the outer periphery of the metal block. The metal carrier can be formed in a shape close to a cylindrical shape with few gaps formed therebetween.

[0041]

According to the first aspect of the invention, since the metal mass for increasing the heat capacity is integrally provided in the honeycomb carrier of the catalyst, and the metal mass is kept in a heat-insulated state from the outer cylinder of the honeycomb body, Since the heat capacity of the catalyst increases, it is possible to prevent a sudden temperature decrease of the activated catalyst once the engine is stopped.

According to the second aspect of the present invention, since the metal mass is formed in a plate shape thicker than the metal foil forming the honeycomb carrier, the heat capacity increases, and the temperature of the catalyst sharply decreases after the engine is stopped. Can be prevented.

In the third aspect of the present invention, since the metal lumps are concentrically arranged in the honeycomb carrier, the heat capacity is increased, and a sudden temperature decrease of the catalyst is avoided after the engine is stopped. be able to.

In the fourth aspect of the present invention, since the metal lumps are arranged in a spiral shape in the honeycomb carrier, the heat capacity is increased, and it is possible to avoid a sudden temperature decrease of the catalyst after the engine is stopped. .

Therefore, in the inventions of claims 1 to 4, since the temperature does not immediately drop even after the engine is stopped, the deterioration of the catalyst cleaning action is avoided if the engine is restarted after being stopped for a short time. And the catalytic reaction can be performed efficiently.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is a perspective view showing a second embodiment of the present invention.

FIG. 3 is a perspective view showing a third embodiment of the present invention.

[Explanation of symbols]

 1 Metal catalyst 2 Metal carrier 3 Plate 6 Cylindrical 8 Plate

Claims (4)

[Claims] 1. A catalyst device, wherein a metal mass for increasing the heat capacity of the catalyst is integrally provided in a honeycomb carrier of the catalyst arranged downstream of the exhaust manifold. 2. The catalyst device according to claim 1, wherein the metal mass is a plate-shaped material thicker than the metal foil forming the honeycomb carrier. 3. The catalyst device according to claim 1, wherein the metal mass is provided concentrically in a honeycomb carrier. 4. The catalyst device according to claim 1, wherein the metal block is provided in a spiral shape in the honeycomb carrier.