JPH0325607B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a particulate purification device for a diesel engine, and particularly to control when energizing an electric heater provided in the particulate purification device.

Exhaust gas discharged from a diesel engine is passed through a trap installed in the exhaust passage, and particulates such as soot (hereinafter referred to as particulates) contained in the exhaust gas are passed through a porous ceramic material that constitutes the trap. It is collected by a collection material consisting of: As time passes, particulate accumulates in the trap, increasing pressure loss and increasing engine output loss. Therefore, before particulate accumulates to a certain extent and affects output, the particulate is incinerated and removed to regenerate the trap. There is a need.

This regeneration can be done either by placing an electric heater on the collection material and using the electric heater to directly ignite the particulate and burning it, or by restricting intake and exhaust air to raise the exhaust gas passing through the collection material to a temperature above the combustion temperature of the particulate. This is done by letting the heated exhaust gas burn the particulate. The electric heater uses the same battery as the power source for headlights, taillights, and other electrical equipment in the vehicle. Powering the electric heater consumes a relatively large amount of power, so if the electric heater is turned on for trap regeneration when the battery is not fully charged, the battery will overheat and other It may interfere with the operation of electrical equipment.

The object of the present invention is to prevent battery build-up due to energization of the electric heater in a diesel engine equipped with an electric heater for trap regeneration.

To achieve this objective, in the diesel engine particulate purification device of the present invention, an electric heater installed in the trap is connected to a computer, and the timing of energization is controlled by the computer. On the other hand, the fuel injection pump is provided with an actuator that increases or decreases the amount of fuel supplied from the fuel injection pump, and this actuator usually consists of a diaphragm device, and its operation is controlled by the computer. There is. Then, the computer controls the electric heater and the fuel injection pump so that if the engine is idling when the electric heater is energized, the fuel supply amount is increased to increase the idle. It is associated.

In such a device, when the engine is idling while the electric heater is energized, the engine is controlled by a computer to increase the idle and keep the engine speed relatively high. In conventional engines that do not have this kind of control, the engine speed is low at idle, and the amount of power supplied from the alternator, which supplies power in proportion to the engine speed, is small, so it is difficult to compare When power is started to be applied to the trap's electric heater, which consumes a large amount of electric power, the battery may become exhausted, which may cause various troubles to other electrical devices in the vehicle that use the battery as a power source. However, in a device like the present invention, where the idle rotation is increased while the electric heater is energized, there is a margin in the power supplied from the alternator, so even if the electric heater consumes power, the battery will not run out. No phenomenon occurs.

The technology of igniting particulate by energizing an electric heater has existed for some time, but
Conventionally, the technology was limited to the inside of a trap, and unlike the present invention, there was no control of energization to an electric heater in relation to other equipment in the vehicle, and it was not possible to link it to idle up by a fuel injection pump. This prevents the battery from rising.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the diesel engine particulate purifying device of the present invention will be described below with reference to the drawings.

FIG. 1 shows a system of an embodiment of a diesel engine particulate purification device according to the present invention. In the figure, 1 is an exhaust passage of a diesel engine, and 2 is a trap for collecting particulate matter in the exhaust gas. Trap 2 has bypass passage 3
A bypass valve 4 is provided in the bypass passage 3. The bypass valve 4 is opened and closed by a diaphragm 5, and the diaphragm 5 is operated by VSVs 6 and 7.
One VSV6 is connected to the vacuum pump,
The other VSV7 connects to the atmosphere. Trap 2
A collection material 8 is charged in the container, and an electric heater 9 for igniting the particulate is provided upstream of the collection material 8. This electric heater 9 is body grounded. Further, the trap 2 is provided with a temperature detection sensor 10, which detects, for example, the temperature of the incoming gas. The electric circuit of the electric heater 9 is provided with a battery 11 and a relay 12 that turns on and off power to the electric heater 9. Reproduction is controlled by computer 13 (ECU). When the ECU 13 determines that the regeneration time has come, the bypass valve 4 is opened by operating the VSVs 6 and 7, the relay 12 is turned on, the electric heater 9 is energized, and the exhaust gas flowing through the trap 2 is is controlled by opening and closing bypass valve 4, while trap 2
is played back. The computer 13 has this control function.

On the other hand, the fuel injection pump 15 that supplies fuel to the diesel engine body 14 is equipped with a diaphragm device 16 as an actuator, as shown in FIGS. 2 and 3, so that the amount of fuel supplied can be increased or decreased. There is. That is, the rod 17 retracting from the diaphragm device 16 is connected to the arm 1.
8 around the fulcrum 19, and the arm 21 is rotated by the push rod 20 attached to the tip of the arm 18, thereby causing the fuel injection pump 1 to rotate.
5. Increase or decrease the opening degree of the fuel passage. 22 is a drive gear of the pump, and 23 is a fuel discharge port. A pipe 24 from a vacuum pump is connected to the diaphragm device 16, and a vacuum switching valve (VSV) 25 is provided in the middle of the pipe to switch between negative pressure or atmospheric pressure introduced into the diaphragm device 16. The vacuum switching valve 25 is connected to the computer 13 and controls the operation of the diaphragm device 16 under the control of the computer 13, thereby controlling the amount of fuel supplied by the fuel injection pump 15.

The computer 13 has a control function as shown in the flow chart of FIG. That is, if the engine's cumulative rotation speed n is a certain rotation speed no, for example
It is determined whether the regeneration time has come by determining whether the rotation has reached 200,000 revolutions or more.If n<no, the integration is continued, and if n≧no, it is assumed that the regeneration time has come. Start energizing the heater 9. At this time, in order to determine whether the engine is in idle operation, the engine speed N is set to the idle speed _N1 (for example,
700rpm). When idling, the idle is increased, so the actual engine speed N is the engine speed Nu (e.g.
1000rpm). and N is Nu or
When it is smaller than Nu, it is assumed that it is during idling operation, and the opening degree of the fuel injection pump 15 is increased via the VSV 25 and the diaphragm device 16 to increase the idling. Further, when N is larger than Nu, the opening degree of the fuel injection pump 15 is maintained at the normal opening degree. Regeneration is performed in this state. The electric heater 9 is usually divided into a plurality of parts due to capacity, and the electric heaters 9 are energized one by one in order. Electricity is applied to burn the particulate for a certain period of time, and then the electricity to the electric heater 9 is stopped and the opening degree of the fuel injection pump is returned to the normal opening degree to complete the regeneration. A computer 13 is configured to perform these controls, and the electric heater 9 and the fuel injection pump 15 are associated with each other via the computer 13.

Next, the operation of the apparatus configured as described above will be explained.

In FIG. 1, the bypass valve 4 is normally closed and the exhaust gas flows through the trap 2.
Particulate matter in the exhaust gas is collected by the collection material 8, and the exhaust gas is purified and discharged into the atmosphere. When the cumulative number of engine revolutions exceeds a certain number of revolutions, for example 200,000 revolutions, the computer 13 determines that it is time for regeneration, and the bypass valve 4 opens. Subsequently, the electric heater 9 is energized by the relay 12 . At this time, it is determined whether or not the engine is idling by determining whether the engine speed is below a certain speed, and if the engine is idling, the computer 13 controls the fuel injection pump 1
Increase the amount of fuel supplied in step 5 to increase the engine speed and increase the idle. As a result, the amount of power generated by the alternator increases, a surplus is created in the amount of power supplied by the alternator, the load on the battery is reduced, and battery exhaustion is avoided. Of course, when the engine speed is medium to high speed, the alternator generates enough power, and the fuel injection pump 15
The fuel supply does not need to be increased and will continue to operate normally.

Therefore, in the diesel engine particulate purification device of the present invention, in energizing the electric heater during trap regeneration, we go one step further than the conventional method of simply energizing the electric heater to ignite the particulate, and install a computer to ignite the particulate. When the heater is energized, the amount of fuel supplied by the fuel injection pump is increased when the engine is idling to increase the idle power.In other words, when the engine is idling and there is not enough battery power, the engine generates more power from the alternator. So,
According to the present invention, it is possible to prevent the battery from rising when the trap is regenerated, and it is possible to prevent various troubles caused by the battery from rising.

[Brief explanation of drawings]

Fig. 1 is a system diagram of a particulate purification device for a diesel engine according to an embodiment of the present invention, Fig. 2 is a schematic configuration diagram of a fuel injection pump, and Fig. 3 is a line direction arrow of the fuel injection pump in Fig. 2. 4 is a flow diagram showing the control functions of the computer in the apparatus of FIG. 1. DESCRIPTION OF SYMBOLS 1... Exhaust passage, 2... Trap, 3... Bypass passage, 4... Bypass valve, 8... Collection material, 9... Electric heater, 10... Temperature detection sensor, 11... Battery, 12... ...Relay, 13...
...Computer, 15...Fuel injection pump, 16
...actuator (diaphragm device), 25
...VSV.

Claims (1)

[Claims] 1. An electric heater is provided in a trap provided in the exhaust passage of a diesel engine, and energization of the electric heater is controlled by a computer, and an actuator for increasing or decreasing the amount of fuel supplied is provided in the fuel injection pump, and the operation of the actuator is controlled as described above. A computer controls the electric heater and the actuator of the fuel injection pump by increasing the amount of fuel supplied when the electric heater is idling. A particulate purification device for a diesel engine, characterized in that the device is associated with the device to perform the following steps.