JP2782650B2 - Electric heating catalyst 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 electric heating catalyst device provided in an exhaust passage of an engine for activating a catalytic substance.

[0002]

2. Description of the Related Art Conventionally, for the purpose of reducing harmful substances emitted immediately after starting an engine, an electric heating catalyst device for rapidly heating a catalyst immediately after starting the engine has been studied. Such an electrically heated catalyst device 10 is, for example, as shown in FIG.
A battery 15 is provided in the middle of an exhaust passage 13 interposed between a combustion chamber 12 and a muffler 14 of the engine 11 and applies a voltage from a battery power supply 17 to a carrier 15 which is a heating element via a switch 16 in an ON state. Heating the carrier 15 rapidly to activate the catalyst material carried on the carrier 15,
Harmful substances such as CO (carbon monoxide) and HC (hydrocarbon) in the exhaust gas discharged from the combustion chamber 11 have been removed.

[0003]

However, the above-described electric heating catalyst device is basically a uniform resistor, and is uniformly heated by an electric current. And the amount of heat supplied to the catalyst is not effectively utilized.

[0004] The present invention has been made in view of the above problems, and has as its object to provide an electric heating catalyst device capable of efficiently activating a catalytic substance.

[0005]

In order to achieve the above object, according to the present invention, a current path is provided by a slit provided in an exhaust passage of an engine, having a positive electrode and a negative electrode on an outer peripheral portion, and penetrating in a flow path direction. A conductive substrate that is formed and generates heat by the supplied current, and is supported by the substrate;
In addition, the present invention provides an electric heating catalyst device having a catalytic substance activated by heating, wherein the number of the slits is larger in a central portion than in an outer peripheral portion of the base.

[0006]

By forming the number of slits so that the number of the slits is larger in the central part than in the outer peripheral part, the current path in the central part of the base is made thinner, the electric resistance is increased, and the calorific value in the central part of the base is increased. . Therefore, it is possible to reduce the heat loss in the outer peripheral portion, efficiently heat the catalyst substance, and satisfactorily purify the exhaust gas.

[0007]

An embodiment of the present invention will be described with reference to FIG. FIG. 1 is a sectional view showing an embodiment of the electric heating catalyst device according to the present invention. In the figure, the electric heating catalyst device 20
The housing 21, a base 25 made of a heat-resistant alloy, positive and negative electrodes 22 and 23 connected to a battery power supply (not shown) and provided on the outer periphery of the base 25, and provided on the base 25 by arrows in FIG. Base 25
A slit 24 for defining a current path in the substrate,
Catalyst substance carried on the substrate 25 and the housing 2
1 and a heat insulating material 26 disposed between them.

The interval between the slits 24 is small near the center and the number of the slits 24 is large. Therefore, the current path near the center is thinner than the periphery, and the electric resistance is higher. Since the calorific value is proportional to the electric resistance, the calorific value in the central part is larger than that in the peripheral part.

Therefore, in this embodiment, the slits 24 in the vicinity of the center of the apparatus are arranged with a small interval therebetween, so that the amount of heat generated in the center at the time of current supply is made larger than the amount of heat generated in the periphery, and Heat loss from the part can be reduced,
The harmful substances in the exhaust gas discharged from the combustion chamber of the engine (not shown) to the exhaust passage by heating the catalytic substance efficiently,
It becomes possible to purify harmless substances well.

[0010]

As described above, according to the present invention, a current path is formed by a slit provided in the exhaust passage of the engine, having a positive electrode and a negative electrode in the outer peripheral portion, and penetrating in the flow direction. In an electric heating catalyst device having a conductive substrate that generates heat by the applied current and a catalyst substance that is supported on the substrate and that is activated by heating, the number of the slits is larger at the center than at the outer periphery of the substrate. Since more is formed, the amount of heat generated in the central portion increases, the heat loss from the outer peripheral portion is reduced, and the catalyst material can be activated efficiently.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of an electric heating catalyst device according to the present invention.

FIG. 2 is a diagram showing an attached state of an electric heating catalyst device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10, 20 Electric heating catalyst apparatus 11 Engine 12 Combustion chamber 13 Exhaust passage 15 Carrier 17 Battery power supply 21 Housing 22, 23 Electrode 24 Slit 25 Substrate 26 Insulation material

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Claims (1)

(57) [Claims] 1. A conductive base provided in an exhaust passage of an engine, having a positive electrode and a negative electrode on an outer peripheral portion, a current path formed by a slit penetrating in a flow direction, and generating heat by a supplied current. An electric heating catalyst device having a catalyst substance supported on the substrate and activated by heating, wherein the number of the slits is formed more in the central portion than in the outer peripheral portion of the substrate. Electric heating catalyst device.