JP2580095Y2 - Catalyst device for diesel engine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst system for a diesel engine using an oxidation catalyst.

[0002]

2. Description of the Related Art A diesel engine in which an oxidation catalyst is provided in an exhaust pipe of a diesel engine to oxidize HC components discharged from the engine to reduce the emission of HC components into the atmosphere. Is known.

[0003]

When a vehicle equipped with such an oxidation catalyst is idling for a long time, the oxidation catalyst is not activated due to a low exhaust gas temperature. For this reason, since the HC component in the exhaust gas is accumulated in the oxidation catalyst during a long idling, the exhaust temperature rises when the vehicle is started thereafter, but the exhaust temperature reaches the activation temperature of the catalyst. Previously, there was a problem that a large amount of white smoke was discharged due to evaporation of the accumulated HC component.

The present invention has been made in view of the above points, and has as its object to generate white smoke generated when a vehicle is started after prolonged idling in a diesel engine using an oxidation catalyst. It is an object of the present invention to provide a catalyst device for a diesel engine capable of reducing the fuel consumption.

[0005]

A catalyst device for a diesel engine according to the present invention is an exhaust pipe for a diesel engine.
A catalyst part provided in the passage and a part of the exhaust gas inlet of the catalyst part
Switching device having an on-off valve for opening and closing the valve, and idle operation
Operation detection means for detecting the idle operation;
When the idling operation is detected by the output means, the switching device
Activate the valve to close the on-off valve and discharge to the catalyst section.
Reduce the gas gas introduction area and increase
Release the on-off valve to introduce the exhaust gas to the catalyst section.
And means for increasing the

[0006]

When the idling operation is detected, the switching device is operated to close the on-off valve to reduce the area for introducing exhaust gas to the catalyst portion. The amount of the HC component stored in the catalyst portion is reduced.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a catalytic converter of a diesel engine according to an embodiment of the present invention; FIG. 1 is an overall configuration diagram showing a catalyst device of a diesel engine,
FIG. 2 is a diagram illustrating a main part of the oxidation catalyst 13. In the figure, reference numeral 11 denotes a diesel engine. An exhaust port of the diesel engine 11 is connected to an inlet of an oxidation catalyst 13 via an exhaust pipe 12. This oxidation catalyst 13 has a double structure. At the entrance of the inner peripheral portion 131 of the oxidation catalyst 13,
A butterfly valve 14 is provided as an on-off valve for opening and closing a part of the exhaust gas inlet, and restricts passage of exhaust gas to the inner peripheral portion 131 of the oxidation catalyst 13. Further, an outer peripheral portion 132 of the oxidation catalyst 13 is connected to one end of the exhaust pipe 12.

The butterfly valve 14 is driven to open and close by an air cylinder 15, and the cylinder chamber of the air cylinder 15 is connected to an air source 17 via an electromagnetic on-off valve 16.
A drive signal from a controller 18 is input to the solenoid on-off valve 16. Further, an operation signal from an accelerator SW 19 for outputting an ON signal when the accelerator pedal is at an idle position is input to the controller 18. Reference numeral 20 denotes a lever.

Next, the operation of the embodiment of the present invention configured as described above will be described. When idling,
An ON signal is output from the accelerator SW 19 to the controller 18. When the controller 18 receives the ON signal, the controller 18 outputs a drive signal to open the solenoid valve 16. As a result, the compressed air from the air source 17 is sent to the air cylinder 15 via the electromagnetic on-off valve 16, and the butterfly valve 14 is closed by the air cylinder 15. For this reason,
The exhaust gas discharged from the diesel engine 11 is an oxidation catalyst 1
3 to the atmosphere through the outer periphery 132. As described above, when the engine is idling, the exhaust gas temperature of the engine is not high enough to activate the oxidation catalyst 13.
2 is accumulated.

Thereafter, when the vehicle is started by depressing an accelerator pedal (not shown), an off signal is output from the accelerator SW 19 to the controller 18. For this reason,
The controller 18 controls the closing of the electromagnetic on-off valve 16,
The opening of the butterfly valve 16 is controlled.

The HC component accumulated in the oxidation catalyst 13 at the time of idling is reduced to the outer peripheral portion 132 of the oxidation catalyst 13.
Therefore, even if the exhaust gas temperature rises, only a small amount of the accumulated HC component evaporates, so that the generation of white smoke can be greatly reduced.

In the above embodiment, the idle operation is detected by the idle SW, but the low load operation may be detected by a detecting means other than the idle SW. Further, in the above embodiment, the driving of the butterfly valve 14 is not limited to the embodiment, and may be driven by a motor. Further, not only the inner peripheral portion 131 may be closed by the butterfly valve 14 but also the oxidation catalyst 13 may be partially closed.

[0013]

As described above in detail, according to the present invention, in a diesel engine using an oxidation catalyst, the generation of white smoke generated when a vehicle is started after a long idling is reduced. And a catalyst device for the diesel engine.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a catalyst device of a diesel engine according to an embodiment of the present invention.

FIG. 2 is a view showing a main part of an oxidation catalyst according to the embodiment.

[Explanation of symbols]

11 diesel engine, 12 exhaust pipe, 13 oxidation catalyst, 14 butterfly valve, 15 air cylinder, 16
... electromagnetic on-off valve, 17 ... air source.

Claims (1)

(57) [Scope of request for utility model registration] (1)Installed in the exhaust line of the diesel engine
Catalyst part, An on-off valve for opening and closing a part of the exhaust gas inlet of the catalyst unit
A switching device; Idle operation detection means for detecting idle operation; The idle operation is detected by the idle operation detection means.
Then, the switching device is operated to close the on-off valve,
The area for introducing exhaust gas into the catalyst section is reduced,
During operation other than fuel operation, the on-off valve is released to discharge to the catalyst section.
Means for increasing gas gas introduction area And that
Characteristic catalyst device for diesel engine.