JPS5918222A - Exhaust gas purification device for diesel engine - Google Patents

Abstract

PURPOSE:To prevent dry grass or a passerby from being burned by a method wherein in the case of a device for preventing the clogging of a filter by operating a clogging removing means such as a burner, the operation of the clogging removing means is stopped when the vehicle is stopped. CONSTITUTION:When exhaust gases from the diesel engine 1 reaches the filter 4 and then passes through the latter through an exhaust passage 3, carbon particles in the exhaust gases are collected and removed. In case where the filter 4 is clogged, a clogging detector 6 generates an output by detecting the clogging of the filter from the lowering of the resistance value between electrodes 5a and 5b. Thus a fuel pump 13 and an air pump 14 are driven by the output of the clogging detector 6 through a control circuit 16 and the burner 7 is operated by turning an ignition switch 9 ON to thereby remove the clogging. Further, when an output is generated from a vehicle stop detector 15 during the clogging removing operation, the operation of the burner 7 is stopped so that no unfavorable phenomenon takes place due to the operation of the burner 7.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exhaust purification device for a diesel engine.

Generally, exhaust purification devices for diesel engines are installed in the exhaust passage to prevent problems such as air pollution if fine particles such as carbon particles decomposed and liberated from the fuel in the high-temperature combustion chamber are released into the atmosphere. The filter member attempts to collect carbon particles and the like in the exhaust gas to purify the exhaust gas. By the way, when this exhaust purification device is used for a long time (and the amount of carbon particles etc. collected increases), the filter member becomes clogged with the carbon particles, and the pressure of the exhaust gas on the upstream side of the filter member increases. increases and this becomes an operating resistance of the engine, resulting in a problem that the engine output decreases.

Therefore, in order to prevent a drop in engine output, conventional exhaust purification devices use a burner device to prevent the clogging from occurring when the mileage reaches a predetermined distance or when one filter member becomes clogged. Carbon particles are heated to burn the carbon particles to eliminate clogging of filter members (Japanese Patent Application Laid-Open No. 49-1999)
(See Publication No. 71315).

Dry the conventional exhaust gas purification equipment as mentioned above.

When the distance traveled reaches a predetermined distance or when a filter member becomes clogged, the burner device is operated even when the vehicle is stopped. However, if this is done, the temperature of the exhaust gas while the burner device is operating is as high as 60 crc to 1000°C, so the heat of this exhaust gas may cause problems such as burning dry grass on the road surface or burning passersby. Ta. In addition, when installing a burner device while the vehicle is stopped, the engine is in the idle region and the rotation speed is low, and in order to operate the air pump that supplies air to the burner device, the engine is in the idle region. The problem was that an air pump was required.

This invention has been made in view of the above-mentioned conventional problems.In an exhaust purification device having a filter member and a clogging eliminating means such as a burner device in the exhaust passage, the clogging eliminating means is not activated when the vehicle is stopped. The purpose of the present invention is to provide an exhaust purification device for a diesel engine which can eliminate problems such as dry grass burning and burns of passersby, and can downsize the air pump.

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

FIG. 1 shows an exhaust purification device for a diesel engine according to an embodiment of the present invention. In the figure, 1 is a diesel engine, 2 is an intake passage, and 3 is an exhaust passage, and a filter member 4 is disposed in the middle of the exhaust passage 3 to collect fine particles such as carbon particles in the exhaust gas. . This filter member 4 has honeycomb-shaped passages 4a and 4b formed therein, and one of the adjacent passages 4m and 4b4 has an opening on the terminal end side, and the other opening on the starting end side, which are respectively closed by a blind zook 4C. There is. Also, filter member 4
A pair of electrodes 5λ, 5b are attached to the electrode 53.5b, which is connected to a clogging detector 6. The clogging detector 6 energizes the electrode 5a15b so that both electrodes 5a
, 5b, clogging of the filter member 4 is detected.

Further, a burner device (clogging eliminating means) 7 is disposed on the upstream side of the filter member 4 of the exhaust passage 3.
The burner device 7 has an ignition plug 8, and an ignition switch 9 is connected between the ignition plug 8 and a power source (not shown). This burner device 7 has a fuel supply passage 10
and the air supply passage 11 are connected to the fuel supply passage 1.
The number in the middle of 0 means that the fuel in the fuel tank 12 is transferred to the burner device 7.
In the middle of the air supply passage 11, there is an air pump 14 that pumps air to the burner device 7I.
are arranged respectively.

In the diagram, 15 is a stop detector that detects the stopped state of the vehicle from the engine speedometer, etc., and 16 is a drive signal that generates a drive signal to operate the burner device M7 while receiving a detection signal from the clogging detector 6. This is a control circuit that stops generating the drive signal while receiving the detection signal from the stop detector 15.

FIG. 2 shows the circuit configuration of the exhaust purification device, and in the figure, 6.9.13.14.15 are the above-mentioned clogging detector 1 ignition switch, fuel bonnet, air pump, and stop detector. Further, in the control circuit 16, a gate circuit 17 is normally open to allow the detection signal of the clogging detector 6 to pass through, and is closed while receiving an inverted signal of the detection signal of the stop detector 15. operates as an operation stop means for stopping the operation of the burner device 7 when the stop detector 15 detects a stop.

Next, the operation will be explained.0 During operation of the engine 1, when exhaust gas containing fine particles such as carbon particles is discharged from the combustion chamber, this exhaust gas flows through the exhaust passage 3 and reaches the filter member 4. The starting end side of the filter member 4 enters the open passage 4a. Then, since the openings on the terminal side of these passages 4a are closed, the exhaust gas enters the adjacent passage 4b through the side wall of the passage 4a, and passes through the opening on the terminal side of the passage 4b to the filter member 4. is discharged from. At this time, fine particles such as carbon particles in the exhaust gas are collected and removed by the side walls of the passage, thereby purifying the exhaust gas and releasing it into the atmosphere.

Further, if the filter member 4 is clogged with carbon particles collected while purifying the exhaust gas by burning carbon particles, the clogging detector 6 detects the electrodes 5a and 55. It is detected that the filter member 4 is clogged from the resistance value between the detectors 6 and 6.
The detection signal is passed through the gate circuit 17 to the drive circuits 18 to 20.
added to. Then, fuel pump 13 and air pump 1
4 is driven, the ignition switch 9 is turned on, the burner device 7 is operated, and the carbon particles in the filter member 4 are heated and burned, thereby eliminating the clogging of the filter member 4. It will be done.

By the way, if the burner device 7 is activated to clear the blockage while the vehicle is stopped, there is a risk that the dry grass will burn and passersby will be burned, as described above, and the air pump 14 etc. will be large. There is a problem with becoming. However, in this device, when the vehicle is stopped, the stop detector 15 detects that the vehicle is stopped from the speedometer of the engine 1, etc., and the gate circuit 17 detects the stop detector 1.
Since the drive circuits 18 to 20 are closed upon receiving the inverted signal of the detection signal No. 5, the drive circuits 18 to 20 do not receive the output from the clogging detector 6, and the burner device 7 does not operate. Therefore, in this device, the above-mentioned problems such as burns caused by burning dry grass and burns to passersby do not occur, and the air pump 14 and the like can be made small.

In the above embodiment, the clogging of the filter member was detected by electrical resistance, but the clogging may also be detected from the pressure of exhaust gas, the amount of deposited particulates such as carbon particles, etc. Further, the clogging may be cleared not after the clogging is detected, but when the travel distance reaches a predetermined distance. Furthermore, the clogging eliminating means is not a burner device (it may also be a heater device).

As described above, according to the present invention, in an exhaust purification device having a filter and a clogging eliminating means such as a burner device in the exhaust passage, the clogging eliminating means is not activated when the vehicle is stopped, so that dried grass can be burned. It is possible to eliminate problems such as burns to passersby and to reduce the size of air pumps and the like.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an exhaust purification device for a diesel engine according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of the device. DESCRIPTION OF SYMBOLS 1... Engine, 3... Exhaust passage, 4... Filter member, 7... Burner device (clog eliminating means)
, 15... Stop detector (stop detection means), 17...
Gate circuit (deactivation means). Patent applicant Toyo Kogyo Co., Ltd. agent Patent attorney Ken Hayase -107 Figure 1 Figure 2

Claims (1)

[Claims] (1) A filter member disposed in the engine exhaust passage to collect fine particles such as carbon particles in the exhaust gas, and a clogging device that eliminates the clogging by heating when the filter member becomes clogged. An exhaust gas for a diesel engine, comprising a clogging eliminating means, a stop detecting means for detecting a stopped state of a vehicle, and an operation stopping means for stopping the operation of the clogging removing means when the stop detecting means detects a stop. Purification device.