JPH05202737A - Exhaust emission control device for automobile - Google Patents

Abstract

PURPOSE:To efficiently eliminate hydrocarbon (HC) generated immediately after start of an engine in a simple method. CONSTITUTION:This device is provided with an engine 1, a battery 2, a cold- start exhaust-gas purifying catalyst unit 6, a magnetron 7, a micro-wave control device 9, a preheat switch 10 and a temperature switch 11. Either in the state where a door key is inserted or a door is opened or in the state where an engine key is inserted when seated on a driver's seat, the preheat switch 10 is turned on so as to generate micro waves and heat a catalyst.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle exhaust gas purifying apparatus.

[0002]

2. Description of the Related Art Most conventional exhaust gas purifying apparatuses for automobiles employ a main metal exhaust gas purifying apparatus and a sub metal exhaust gas purifying apparatus at two locations. However, since the volume of the exhaust gas purifying device of each of the main and subordinate automobiles is about 1000 cc, a large amount of electric power is required to raise the temperature of the catalyst to a temperature at which the catalyst works (about 350 ° C or higher) in a short time. , It was necessary to increase the battery capacity so much that it was not put into practical use. Therefore, it was not possible to remove hydrocarbons (HC) that are often generated when the engine is started.

[0003]

SUMMARY OF THE INVENTION As described above, the conventional structure cannot remove hydrocarbons (HC) and has not been put into practical use. However, from the standpoint of the global environment, it has become necessary to establish a method for removing this that cannot be left unattended. However, as shown in FIGS. 3a, 3b, and 3c, most of the hydrocarbons (HC) are generated in a cold state immediately after the engine is started. Therefore, there is a problem that the catalyst does not work until about 1 minute after the temperature of the catalyst rises.

The present invention has been made to solve the above problems and has as its object the purification of toxic gases, particularly hydrocarbons (HC), in exhaust gas of automobiles immediately after the engine of the automobile is started.

[0005]

In order to achieve the above object, the present invention provides an exhaust gas purifying apparatus equipped with a catalyst in an exhaust portion of an engine of an automobile, and a means for heating the catalyst when the engine is started. , When the door key of the automobile is inserted or the door is opened, the driver is seated, or the engine start key is inserted, the means for heating the catalyst is activated. It is a thing.

[0006]

With the above structure, the present invention can raise the temperature of the catalyst to a temperature at which exhaust gas can be purified (about 350 ° C.) immediately after the engine of the automobile is started, and particularly hydrocarbons (HC ) Can be reduced.

[0007]

Embodiments of the present invention will be described below with reference to FIGS.

1 to 3, 1 is an engine, 2 is
Is a battery for starting the engine, 3 is a manifold that connects the exhaust of the engine to the exhaust pipe, and 4 is a main metal exhaust gas purification catalyst unit (commonly known as a three-way catalyst), which serves to purify various toxic exhaust gases. Reference numeral 5 denotes a sub exhaust gas purifying catalyst unit, which works to completely purify harmful exhaust gas that could not be purified by the main metal exhaust gas purifying catalyst unit. 6
Is a cold start exhaust gas purifying catalyst unit, which is made of a material such as ceramics that transmits microwaves and is coated or impregnated with a radio wave absorber and attached with a catalyst material. 7
Is a magnetron for generating a microwave, 8 is a waveguide for supplying the microwave generated by the magnetron 7 to the cold start exhaust gas purification catalyst unit 6, and 9 is a microwave for controlling the generation of microwaves. The control device 10 is a preheat switch for operating the cold start exhaust gas purification catalyst unit 6 a little faster than the start of the engine 1 to raise the temperature, and is a key for the driver to open the door of the car to drive the car. When the preheat switch 9 is actuated and the engine 1 is started, the cold start exhaust gas purification catalyst unit is already activated because it works when the engine is inserted, the door is opened, the seat is seated, or the key is inserted to start the engine. 6 is heated, and is further superposed by the exhaust gas from the engine 1 and immediately after the engine is started. Toxic gases, especially hydrocarbons raw (H
The ability to purify C) is improved, 11 is once engine 1
The engine 1 is turned off after the temperature of each of the installed catalysts 4, 5 or 6 has risen, and the engine 1 is restarted, and restarted when each of the catalysts 4, 5, 6 is not cold (the temperature is raised). It is a temperature sensor for stopping the generation of microwaves when it does.

FIG. 2 shows a second embodiment of the essential part of FIG.
Since the waveguide 8 for irradiating the cold start exhaust gas purifying catalyst unit 6 with the radio waves generated from the magnetron 7 is too large and the mounting position is limited, a flexible coaxial cable 12 is used instead of the waveguide 8. The magnetron mounting position has flexibility. When the main metal exhaust gas purification catalyst unit 4 is made of ceramics, the microwave is mainly used (ceramic).
The cold start is absorbed by the exhaust gas purification unit 4 and the irradiation amount of microwaves to the exhaust gas purification catalyst unit 6 is reduced and the temperature rise is slowed down. The microwave shielding plate 13 is provided.

3a, 3b and 3c are timing charts showing the relationship between the operation of the cold start exhaust gas purification catalyst unit 6, the purification rate (temperature rise), the amount of hydrocarbon (HC) generated and the purification based on experimental data. The change in the exhaust gas purification rate due to the difference in the preheat time lag is clearly understood. The curve A is an example of the exhaust amount of hydrocarbons (HC) in the state without the cold start exhaust gas purifying apparatus of the present invention, and actually varies greatly depending on the engine speed (how the accelerator is depressed). Curve B is the average temperature rise value of the cold start exhaust gas purification catalyst, and at the same time is the purification rate of the catalyst. According to the apparatus of the present invention, when the cold start exhaust gas purifying apparatus is operated, the temperature of the catalyst is about 5-1.
It is around 350 ° C where the catalyst works in 0 seconds. A curve C is a product of the hydrocarbon (HC) concentration and the purification rate and represents the purification state.

FIG. 3a is a chart when the cold start exhaust gas purifying apparatus is started and the engine is started at the same time. Almost no purification is performed for about 10 seconds after the engine is started.

FIG. 3b is a chart when the cold start exhaust gas purifying apparatus is started when the passenger is seated in the seat, and the purifying is hardly performed for about 5 seconds after the engine is started.

FIG. 3c is a chart when the cold start exhaust gas purifying apparatus is started when the door key is inserted. Purification starts immediately after the engine starts and almost no hydrocarbon (HC) is discharged.

[0014]

As described above, the exhaust gas purifying apparatus of the present invention has an effect that hydrocarbons (HC), which are often generated in a short time after the engine is started, can be purified very efficiently.

[Brief description of drawings]

FIG. 1 is a configuration diagram according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a main part according to a second embodiment of the present invention.

[Fig. 3] Timing chart for exhaust gas purification

[Explanation of symbols]

 1 Engine 6 Cold start Exhaust gas purification catalyst unit 7 Magnetron 9 Microwave controller 10 Preheat switch

Claims (4)

[Claims] 1. A catalyst is provided in an exhaust portion of an automobile engine,
When the means for heating the catalyst is provided at the time of starting the engine, when the door key of the vehicle is inserted or the door is opened, the driver's seat is seated, or the engine key is inserted, An exhaust gas purifying device for an automobile having a structure for activating a means for heating a catalyst. 2. The exhaust gas purifying apparatus for an automobile according to claim 1, wherein the single body for the catalyst is located between the manifold and the main metal exhaust gas purifying catalyst. 3. A means for heating a catalyst at engine start-up,
2. The exhaust gas purifying apparatus for an automobile according to claim 1, wherein the exhaust gas purifying apparatus for a vehicle according to claim 1, wherein when the engine is started once and the temperature of the catalyst is raised, the engine is stopped and restarted. 4. The exhaust gas purifying apparatus for an automobile according to claim 1, wherein the means for heating the catalyst comprises a microwave generating means.