JPH037009B2 - - Google Patents

Description

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

Conventionally, in diesel engines, filter members have been used to collect particulate components such as carbon particles in exhaust gas in order to prevent them from being released into the atmosphere, as shown in Japanese Patent Laid-Open No. 56-124618. is placed in the exhaust passage, and
A heater is provided on the upstream side of the filter member, and the temperature of the exhaust gas is increased by delaying the timing of fuel injection by the fuel injection pump, and after preheating the filter member, the particulate components collected by the filter member are heated by the heater. A diesel engine exhaust gas purification device that eliminates exhaust gas by combustion has been proposed, but the use of a heater has the disadvantage of reducing fuel efficiency.

In view of this, the present invention provides a cylinder reduction operation mechanism that increases the amount of fuel injection in a specific cylinder while stopping fuel injection in the remaining cylinders, in which a filter member for collecting particulate components in exhaust gas is provided in the exhaust passage. and a shutoff device that shuts off the introduction of exhaust gas from the remaining cylinders to the filter member, and when the filter member is clogged or at predetermined intervals, the cylinder reduction operation mechanism and the shutoff device are activated to perform cylinder reduction operation. To provide an exhaust gas purification device for a diesel engine, which is equipped with a control device for preventing exhaust gas from remaining cylinders from being introduced into a filter member, and to effectively increase the temperature of the filter member without having a heat source such as a heater. This is intended to reliably eliminate clogging of the filter member.

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

Embodiment 1 In FIG. 1, 1 is a multi-cylinder (4-cylinder) diesel engine, and 2 is each cylinder 1A of the engine 1.
This is an exhaust passage that leads out exhaust gas from ~1D. The exhaust passage 2 includes a filter member 4 that collects particulate components such as carbon particles in the exhaust gas.
A reactor 3 coated with an oxidation catalyst is disposed.

The filter member 4 of the reactor 3 is formed in a honeycomb shape from a porous material such as ceramic.
Every other pore along the exhaust flow is closed at its end, and the exhaust gas that flows in from the open pore at one end passes through the permeable porous partition wall and passes through the open pore at the other end. The filter member 4 is configured to collect fine particles such as carbon particles in the exhaust gas when it passes through the partition wall, and the surface of the filter member 4 is coated with an oxidation catalyst made of noble metal or base metal.

The exhaust passage 2 has an upstream portion of the reactor 3.
A first exhaust passage 2a that constantly guides exhaust gas from specific cylinders 1B and 1C (second and third cylinders) to the filter member 4
and a second exhaust passage 2b that guides exhaust gas from the remaining cylinders 1A and 1D (first and fourth cylinders) to the filter member 4, and the first and second exhaust passages 2a,
2b joins upstream of reactor 3.

Further, reference numeral 5 denotes a shutoff device that shuts off the introduction of exhaust gas from the remaining cylinders 1A and 1D to the filter member 4, and this shutoff device 5 branches from the second exhaust passage 2b and bypasses the filter member 4. A bypass passage 6 is formed, and a remaining cylinder 1 is provided at a branch part between the second exhaust passage 2b and the bypass passage 6.
A switching valve 7 is provided to switch whether the exhaust gas from A, 1D is introduced into the bypass passage 6 or into the reactor 3, and the switching valve 7 is operated by an actuator 8. During operation, the bypass passage 6 is opened and the remaining cylinders 1A, 1
It is configured to prevent the exhaust gas from D from being introduced into the filter member 4.

On the other hand, reference numeral 9 indicates fuel passages 11a to 11a to 10d to fuel injection nozzles 10a to 10d disposed in each cylinder 1A to 1D.
This fuel injection device 9 is a fuel injection device that supplies fuel at a predetermined timing through a cylinder 11d, and this fuel injection device 9 performs reduced-cylinder operation in which it increases the amount of fuel injected into specific cylinders 1B and 1C, while stopping the fuel injection in the remaining cylinders 1A and 1D. It has a mechanism.

That is, the fuel injection device 9
First fuel injection pump 1 that supplies fuel to B and 1C
2A and the second cylinder that supplies fuel to the remaining cylinders 1A and 1D.
The fuel injection pump 12B operates to increase the amount of fuel supplied from the first fuel injection pump 12A during cylinder reduction operation, while stopping the fuel supply from the second fuel injection pump 12B.

Furthermore, 13 is a control device that controls the switching valve 7 of the shutoff device 5 and the operation of the cylinder reduction operation mechanism of the fuel injection device 9. aisle 2
A detection signal from an exhaust pressure sensor 14 that detects the exhaust pressure of the engine and a detection signal from a load sensor 15 that detects the amount of accelerator operation are input, and control is performed in accordance with the detection signals.

The control device 13 inputs the detection signal of the exhaust pressure sensor 14, determines that a state in which the exhaust pressure has become higher than a predetermined value is the occurrence of clogging, and controls the filter member 13 to burn the particulate components in the reactor 3. It increases the temperature of

The control device 13 operates the actuator 8 of the switching valve 7 to open the bypass passage 6 and guide the exhaust gas from the remaining cylinders 1A and 1D to the bypass passage 6 when the filter member 4 is clogged. Only the exhaust gas 2a is introduced, and a control signal is output to the fuel injection device 9 to perform cylinder reduction operation.

Further, the control device 13 is configured to receive a detection signal from the load sensor 15 and output a control signal to the fuel injection device 9 to perform cylinder reduction operation when the load is low.

To explain the operation of the above embodiment, when the filter member 4 of the reactor 3 is clogged, the control device 13 detects the clog by the exhaust pressure sensor 14 and controls the control device 13 to control the specific cylinder 1B by operating the switching valve 7. ，
Only the exhaust gas of 1C is guided to the filter member 4, and the cylinder reduction operation mechanism of the fuel injection device 9 is activated to increase the amount of fuel injection to these specific cylinders 1B, 1C to ensure the required output, while the remaining cylinders 1A,
Stop 1D fuel injection. As a result, the amount of heat generated in the specific cylinders 1B and 1C increases and the exhaust gas temperature rises.

Therefore, in the reactor 3, the temperature of the filter member 4 rises due to the rise in exhaust gas temperature, and the particulate components collected in the filter member 4 are burned and removed. Further, the oxidation reaction of the catalyst increases due to contact with unburned components, and the temperature of the filter member 4 further increases due to the reaction heat, thereby ensuring that the particulate components are burnt out.

At this time, since the air discharged from the remaining cylinders 1A and 1D is bypassed, the filter member 4 is not cooled thereby, and the temperature of the filter member 4 is effectively increased.

In this way, when the filter member 4 is no longer clogged and the exhaust pressure is reduced, the reduced-cylinder operation by the operation of the fuel injection device 9 is stopped and full-cylinder operation is performed.
The bypass passage 6 is closed by the switching valve 7 and the remaining cylinder 1 is closed.
The exhaust gases A and 1D are introduced into the filter member 4, and the particulate components are collected again. If a clogging condition occurs, the clogging is removed in the same manner as described above.

In addition, when the load is low, the control device 13 controls the fuel injection device 9 based on the detection signal from the load sensor 15.
The cylinder reduction operation mechanism is activated, and specific cylinders 1B and 1C are activated.
While increasing the amount of fuel injected into the remaining cylinders 1A and 1D, fuel injection in the remaining cylinders 1A and 1D is stopped to perform reduced-cylinder operation, thereby suppressing white smoke emissions and improving fuel efficiency. In this case as well, the switching valve 7 is operated to open the bypass passage 6 to prevent the temperature of the filter member 4 from decreasing.

Embodiment 2 This example is shown in FIG. 2, where 16 is a diesel engine consisting of a cylinder head 17, a cylinder block 18, a piston 19, etc., and 20 is the engine 1.
Combustion chamber 21 of each cylinder of 6 (remaining cylinder in the case shown)
The exhaust gas from the reactor is led out through an exhaust valve 22 through an exhaust passage, and the exhaust passage 20 is equipped with a reactor 3 equipped with a filter member 4 similar to that of the previous example.
Collects particulate components in exhaust gas.

Further, 23 is a fuel injection device having a cylinder reduction operation mechanism, which includes a fuel injection pump 25 that adjusts the injection amount in response to a control signal from the control device 24 to increase the amount of fuel injection to a specific cylinder, and a fuel injection pump 25 that adjusts the injection amount in response to a control signal from the control device 24 to increase the amount of fuel injection to a specific cylinder. a nozzle selector 2 that stops fuel injection in response to a drive signal from a control device 24 to stop fuel injection;
a fuel injection nozzle 27 having a fuel injection nozzle 6;
Nozzle selector 26 of this fuel injection nozzle 27
is provided to communicate the high pressure passage 28 from the fuel injection pump 25 and the return passage 29 to disable injection when receiving a drive signal from the control device 24.

On the other hand, reference numeral 30 denotes a shutoff device that blocks exhaust gas from being introduced into the filter member 4 from the remaining cylinders in which fuel injection is stopped. The valve selector 32 is connected to the control device 2.
4, the fulcrum position of a rocker arm 34 that links the cam 33 and the exhaust valve 22 is moved backward to hold the exhaust valve 22 in a closed state.

The control device 24 that controls the operation of the fuel injection device 23 and the shutoff device 30 includes, as in the previous example,
Detection signals from exhaust pressure sensor 14 and load sensor 15 are input. This control device 24 outputs a control signal to the fuel injection pump 25 to increase the amount of fuel injected into a specific cylinder when the fuel injection nozzle 27 stops injecting fuel into the remaining cylinders when the blockage occurs.
A drive signal is output to the nozzle selector 26 of the cylinder to perform cylinder reduction operation, and a drive signal is output to the valve selector 32 of the shutoff device 30 to prevent exhaust gas from the remaining cylinders from being introduced into the filter member 4. It is provided.

Therefore, according to the above embodiment, similarly to the previous example, when clogging occurs, cylinder reduction operation is performed to increase the temperature of the exhaust gas discharged from a specific cylinder, and at the same time, the temperature of the exhaust gas discharged from the remaining cylinders in which fuel injection has been stopped is increased. This prevents the particles from entering the filter member, effectively increases the temperature of the filter member 4, and burns out the fine particles collected in the filter member 4.

The present invention is not limited to the structures of the two embodiments described above, but includes various modifications. That is, as the filter member 4, a metal wire mesh may be used instead of porous ceramic.
In addition to the catalyst that is integrally coated on the filter member 4, the filter member 4
A catalyst formed in the shape of a metal wire may be installed upstream of the filter, but this catalyst is not essential, and if it is installed, the rise in filter temperature will be further increased due to the oxidation reaction with unburned components. It is definitely a replacement.

In addition, the above exhaust pressure sensor 1 detects the clogging state.
In addition to the method according to No. 4, an electrode may be provided on the filter member 4 to detect a change in resistance value due to adhesion of carbon particles or the like. Furthermore, without detecting the actual clogging state of the filter member 4, the clogging removal operation may be performed at predetermined intervals based on the integration of operating time or travel distance.

Furthermore, the mechanism for performing reduced-cylinder operation is compatible with the one in the fuel injection device 9 of the first embodiment and the one in the fuel injection device 23 of the second embodiment,
The combination with the blocking devices 5 and 30 can be made arbitrarily.
In addition, known mechanisms can be used as appropriate for the cylinder reduction operation mechanism and the shutoff device.

On the other hand, a temperature sensor for detecting the temperature of the filter member 4 or the exhaust temperature is provided, and the control device 1
3 and 24, the clogging may be cleared only when the temperature detected by the temperature sensor is equal to or higher than a predetermined value. Furthermore, the fuel injection rate may be reduced in response to torque fluctuations when switching to reduced cylinder operation.

As explained above, according to the present invention, when the filter member is clogged or at predetermined intervals, the amount of fuel injection in a specific cylinder is increased, while fuel injection in the remaining cylinders is stopped to perform cylinder reduction operation to exhaust the air. By introducing the heated exhaust gas into the filter member and blocking the introduction of exhaust gas from the remaining cylinders into the filter member, the temperature of the filter member is effectively raised and particulate components are reliably combusted. It has the advantage of being able to be removed, maintaining good fuel efficiency, and suppressing the emission of particulate components over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a diesel engine having an exhaust gas purification device according to a first embodiment of the present invention, and FIG. 2 is a schematic diagram of a diesel engine according to a second embodiment of the present invention. 1,16...diesel engine, 2,20...
...exhaust passage, 3 ... reactor, 4 ... filter member, 5, 30 ... cutoff device, 9, 23 ... fuel injection device, 13, 24 ... control device, 14 ... exhaust pressure sensor.

Claims (1)

[Claims] 1. In an exhaust gas purification device for a diesel engine in which a filter member for collecting particulate components in exhaust gas is provided in the exhaust passage, there is provided a cylinder reduction operation mechanism that increases the amount of fuel injection in a specific cylinder while stopping fuel injection in the remaining cylinders. , a shutoff device that shuts off the introduction of exhaust gas from the miscellaneous cylinders to the filter member, and when the filter member is clogged or at predetermined intervals, the cylinder reduction operation mechanism and the shutoff device are activated to perform the cylinder reduction operation and remove the remaining cylinders. 1. An exhaust gas purification device for a diesel engine, comprising a control device for preventing exhaust gas from a cylinder from being introduced into a filter member.