JPH06330735A - Exhaust particles remover of diesel engine - Google Patents

Abstract

PURPOSE:To detect abnormality of an exhaust gas cutoff valve during reactivation of a filter in an exhaust particulates remover of a diesel engine for switching an exhaust cutoff valve at the time of reactivation process of the filter and for carrying out reactivation process in a closed space. CONSTITUTION:The particulates in an exhaust gas are collected by filters 5A, 5B provided on the exhaust tube 2 of an engine 1. Electric heaters HA, HB provided on the end surface of the filters 5A, 5B are electrified at the time of reactivating the filters 5A, 5B, while the filters 5A, 5B are reactivated by feeding secondary air to this exhaust particulates remover, in which the channel of exhaust gas is changed by control valves V1, V2 at the time of reactivation. The discharge pressure PP of an electric air pump 9 or the pressure of the downstream side of the exhaust control valve V1 is detected. The abnormality of the exhaust control valve V1 is reported to the side of an operator by means of the detected pressure value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust particulate remover for a diesel engine, and more particularly, to a filter for collecting particulates contained in the exhaust gas of a diesel engine at the time of regeneration of the exhaust gas to the filter during regeneration. The present invention relates to an exhaust particle removal device for a diesel engine that can detect an abnormality in an exhaust control valve that blocks inflow.

[0002]

2. Description of the Related Art Exhaust gas of an internal combustion engine of an automobile or the like, especially a diesel engine, contains exhaust particulates (particulates) containing carbon as a main component, which is a cause of exhaust black smoke. From the viewpoint of environmental pollution, it is desirable to remove the particulates. In recent years, it has been proposed to dispose a diesel particulate by this filter by disposing a ceramic filter in the exhaust passage of the diesel engine.

[0003] In an exhaust particulate remover configured to remove particulates by a ceramic filter disposed in the exhaust passage of a diesel engine, the particulates trapped inside the particulate filter when the particulate filter is used. When the amount of the particulate matter is increased, the air permeability is gradually lost and the engine performance is deteriorated. Therefore, it is necessary to periodically regenerate the filter in which the particulates are trapped to some extent.

The judgment of the regeneration time is made by detecting the amount of particulates trapped in the filter, and the amount of particulates trapped in the filter is usually detected by the exhaust gas on the upstream side of the particulate filter. And the differential pressure (pressure loss) on the downstream side. That is, it is judged that the regeneration time is reached when the pressure difference becomes larger than a predetermined value.

In the filter regeneration process, generally, a filter that collects particulates is separated from an exhaust gas flow path by an exhaust cutoff valve, and a regeneration gas, for example, secondary air is supplied to the filter into which the exhaust gas does not flow. At the same time, the electric heater is energized and heated to ignite the particulates in the filter and burn the particulates.

[0006] For example, in Japanese Patent Laid-Open No. 4-109019, secondary air is supplied at the time of regeneration processing in accordance with the pressure difference between the upstream side and the downstream side of the filter, and the flow direction of the exhaust gas is in the opposite direction. An apparatus for reproducing is disclosed.

[0007]

However, in the exhaust particle removing device of the diesel engine which performs the regenerating process by flowing the secondary air in the opposite direction of the flow of the exhaust gas, the regenerating process is performed due to the abnormality of the exhaust gas cutoff valve. Sometimes, when exhaust gas cannot be completely blocked, there is a problem that exhaust gas flows into the filter side during regeneration, obstructs the flow of secondary air, and unburned residue occurs due to insufficient secondary air. Japanese Patent Laid-Open No. Hei 4
In the technique described in Japanese Patent Laid-Open No. -1019019, the differential pressure between the upstream and downstream of the filter is detected during the regeneration process, but there is no disclosure regarding the detection of the abnormality of the exhaust cutoff valve that blocks the exhaust gas during the regeneration process. However, there is a fear that such cases cannot be dealt with sufficiently.

In view of the above, the present invention relates to a conventional diesel engine exhaust particulate removal device constructed so that exhaust gas does not flow into the filter being regenerated by using an exhaust cutoff valve during the filter regeneration process. Another object of the present invention is to provide an exhaust particulate removal device for a diesel engine that can detect an abnormality in the exhaust gas cutoff valve.

[0009]

The exhaust particle removing apparatus for a diesel engine of the present invention which achieves the above object, collects particulates in exhaust gas by a filter provided in an exhaust passage of the engine, and regenerates the filter. With the exhaust control valve blocking the inflow of exhaust gas to the filter that trapped particulates, the particulates that are trapped on the filter are ignited and the regeneration gas is supplied from the regeneration gas supply means to a diesel engine. In the exhaust particulate removal apparatus, a means for detecting the discharge pressure of the regeneration gas supply means or a pressure on the downstream side of the exhaust control valve, and a means for judging abnormality of the exhaust control valve based on the detected pressure value. The feature is that it is provided.

[0010]

According to the exhaust particle removing apparatus for a diesel engine of the present invention, when the filter that collects the particulates in the exhaust gas is regenerated, the filter for controlling the exhaust gas is blocked by the exhaust control valve. When the particulates inside are ignited and the regeneration gas is supplied from the regeneration gas supply means, the discharge pressure of the regeneration gas supply means or the pressure on the downstream side of the exhaust control valve is detected, and the detected pressure The value determines the abnormality of the exhaust control valve.

[0011]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows a schematic configuration of an embodiment of an exhaust particulate removing device 20 of a dual filter type diesel engine of the simultaneous collection and reverse flow alternating regeneration according to the present invention. In the exhaust gas particulate remover 20 of the diesel engine of this embodiment, the exhaust pipe 2 for guiding the exhaust gas from the engine 1 is
It branches into branch pipes 2A and 2B at the branch portion a, and then merges at the merge portion b to be connected to the muffler 6. Casing 3 provided in the middle of the branch pipes 2A, 2B
A first filter 5A and a second filter 5B are provided in A and 3B, respectively, for collecting particulates in the exhaust gas.

Each of the filters 5A and 5B is a honeycomb filter having partition walls made of a porous material such as ceramic, and is generally cylindrical, and has a large number of rectangular parallelepiped passages (filter cells) surrounded by partition walls. ). Adjacent ones of these passages are closed passages that are alternately plugged with ceramic plugs (plugs) on the exhaust gas inflow side and the exhaust gas outflow side. Therefore, the particulates in the exhaust gas flowing into the filters 5A and 5B are collected by the filter cell when the exhaust gas passes through the wall surface of the filter cell.

Further, pressure introducing pipes SPU and SPD are provided on the upstream side of the branch portion a of the branch pipes 2A and 2B and on the downstream side of the joining portion b, respectively, and the differential pressure sensor 10 is provided upstream of the branch portion a. The pressure on the side and the pressure on the downstream side of the merging portion b are introduced. Then, the pressure difference (pressure loss) between the upstream and downstream sides of the filters 5A and 5B is obtained by the differential pressure sensor 10, and the detected value is input to the ECU (control circuit) 100. The control circuit 100 determines the regeneration timing of the filters 5A and 5B based on this pressure difference (differential pressure).

On the other hand, electric heaters HA and HB for heating the filters and igniting the particulates near the downstream end faces of the filters 5A and 5B, or at the plug members (not shown) at the downstream end, during filter regeneration. The electric heaters HA and HB have one end grounded and the other end connected to the battery 11 via switches SWA and SWB controlled by the control circuit 100. Furthermore, filter 5
A temperature sensor ST that detects the exhaust gas temperature is provided upstream of A and 5B, and the detected value ThG of the exhaust temperature of this temperature sensor ST is also input to the control circuit 100. Although not shown, the engine 1 is provided with an intake air temperature sensor for detecting the intake air temperature, an intake air amount sensor for detecting the intake air amount, and a water temperature sensor for detecting the temperature of the engine 1 by the water temperature. The intake air amount Ga, the intake air temperature ThA, and the water temperature ThW from these sensors are also input to the control circuit 100.

The branch part a is provided with a first control valve V1 for distributing the flow of exhaust gas from the exhaust pipe 2 on the upstream side of the branch part a to the branch pipes 2A and 2B, and the junction part b is branched. A second control valve V2 is provided for switching the connection to the exhaust pipe 2D on the downstream side of the joining portion b of the pipes 2A and 2B. Both of the control valves V1 and V2 are driven by the control circuit 100, and the control valves V1 and V2 are controlled by a control signal from the control circuit 100 so that the branch pipes 2A and 2B are not closed, or a branch position. It is positioned at a position where either one of the tubes 2A and 2B is closed.

At the time of reproducing the above-mentioned filters 5A and 5B,
It is necessary to energize the electric heater HA or HB, to flow the regeneration gas from the downstream side of the energized side of the filter 5A or the filter 5B, and to discharge the combustion gas from the upstream side. Therefore, in this embodiment, the branch pipe 2
A regeneration gas supply pipe 7 is provided between the merging portion b of A and 2B and the filters 5A and 5B, and an electric air pump 9 for supplying secondary air is provided at one end of the regeneration gas supply pipe 7. ing. A check valve V3 is provided in the regeneration gas supply pipe 7 on the secondary air discharge side of the electric air pump 9, and an opening / closing valve V5 is provided at a connection portion of the regeneration gas supply pipe 7 to the branch pipes 2A and 2B. , V6 are provided. Further, the regeneration gas supply pipe 7 between the discharge port of the electric air pump 9 and the check valve V3 has a pressure sensor 1 for detecting the pressure between the check valve V3 and the discharge port of the electric air pump 9.
3 is provided. The pressure detection value PP of the pressure sensor 13 is also input to the control circuit 100.

A combustion gas discharge pipe 8 is provided between the branch portions a of the branch pipes 2A and 2B and the filters 5A and 5B, and one end of the combustion gas discharge pipe 8 is open to the atmosphere. A check valve V4 is provided near the open end of the combustion gas discharge pipe 8, and opening / closing valves V7 and V8 are provided at the connection portions of the combustion gas discharge pipe 8 to the branch pipes 2A and 2B, respectively. The valves V3 to V8 and the electric air pump 9 are all driven and controlled by the control circuit 100.

The valves V1 to V8 are actually driven by a diaphragm type actuator, a negative pressure switching valve, or an electric type actuator, but the drive mechanism is not particularly limited, and therefore is shown here. And their description is omitted. However, in the present invention, it is necessary to switch some of the valves V1 to V8 immediately when the engine is started. Therefore, when a diaphragm type actuator or a negative pressure switching valve is used, the vehicle is controlled by a negative pressure tank or the like. Source must be provided.

The control circuit 100 includes, for example, an interface INa for inputting an analog signal, an interface INd for inputting a digital signal, a converter A / D for converting an analog signal into a digital signal, a central processing unit CPU for performing various arithmetic processes, and a random processor. Access memory RAM, read-only memory ROM, backup memory B-RA that retains data even when the engine key switch is turned off
Although it is composed of a microcomputer including M, the output circuit OUT, and the bus line 111 connecting them, detailed description of the operation of the structure will be omitted.

The particulate filter 5 is provided in the interface INa for inputting the analog signal of the control circuit 100.
A differential pressure signal PD of the exhaust gas on the upstream and downstream sides of A and 5B,
The intake air temperature signal ThA, the water temperature signal ThW of the engine 1, the engine speed signal Ne from a speed sensor (not shown), the pressure PP between the check valve V3 and the discharge port of the electric air pump 9, and the like are input and used for digital signal input. Interface I
A signal or the like from the key switch is input to Nd. The output circuit OUT of the control circuit 100 has a control valve V
A valve abnormality lamp 12 indicating abnormality of 1 and V2 is connected.

Next, the operation of the exhaust particle removing device 20 of the diesel engine of the embodiment constructed as described above will be explained.

[When collecting particulates in exhaust gas]
The control valves V1 and V2 are controlled to the neutral position, and the check valves V3 and V4 and the open / close valves V5 to V8 are closed. FIG. 1 shows this state, and the diesel engine 1
The exhaust gas discharged from the exhaust gas flows into both the branch pipes 2A and 2B, the particulates are removed by the filters 5A and 5B, and the exhaust gas is discharged into the atmosphere through the muffler 6.

[When the filter is regenerated] Filters 5A and 5B
When the amount of collected particulates in the inside exceeds a predetermined value and the differential pressure detection values on the upstream side and downstream side of the filters 5A and 5B of the differential pressure sensor 10 exceed the reference value, the filter regeneration processing is executed from the filter 5A. It When the filter 5A is regenerated, the control valves V1 and V2 close the inlet side and the outlet side of the branch pipe 2A, and the check valves V3 and V4 and the open / close valves V5 and V7 are opened. Secondary air from the air pump 9 is the regeneration gas supply pipe 7
Is supplied to the filter 5A through the heater HA, and the heater HA is energized to burn the particulates in the filter 5A.
The combustion gas is discharged into the atmosphere through the combustion gas discharge pipe 8. At the time of regeneration of the filter 5B, the control valves V1 and V2 close the inlet side and the outlet side of the branch pipe 2B, and check valves V3 and V4.
Remains open, the on-off valves V5 and V7 close, and the on-off valve V
6, V8 opens. The secondary air from the air pump 9 is supplied to the filter 5B through the regeneration gas supply pipe 7, the heater HB is energized, the particulates in the filter 5B burn, and the combustion gas passes through the combustion gas discharge pipe 8. Emitted into the atmosphere.

FIG. 2 shows the operation of the control circuit 100 for detecting an abnormality in the control valves V1 and V2 during the filter regeneration processing in the embodiment shown in FIG. This reproduction process is actually executed in the form of an interrupt at predetermined time intervals, but here, in order to briefly show the overall flow of the process,
The reproduction process is shown as a continuous flow from the start to the end, and an interval is provided in the middle of the process to indicate that the reproduction process is executed at predetermined time intervals. All subsequent flow charts will be described in this form.

In step 201, the differential pressure PD is detected, and in step 202 it is judged whether or not it is the regeneration time. The determination of the regeneration timing is performed based on whether the output value PD of the differential pressure sensor 10 is the determination value or more. When it is not the regeneration time, after a predetermined interval (indicated by □), the differential pressure PD is detected again in step 201, and the process of determining whether it is the regeneration time or not is repeated in step 202. On the other hand, when it is determined in step 202 that the reproduction time has come, the routine proceeds to step 203.

At step 203, the reproduction process of the filter 5A is executed. At the time of the regeneration process of the filter 5A, the control valve V
1, V2 block the inlet side and the outlet side of the branch pipe 2A, and the check valves V3, V4 and the open / close valves V5, V7 are opened. In this state, the secondary air from the electric air pump 9 is supplied to the filter 5A through the regeneration gas supply pipe 7 to energize the heater HA. The heater HA is energized to ignite and burn the particulates in the filter 5A, and the combustion gas is discharged into the atmosphere through the combustion gas discharge pipe 8. At this time, the exhaust gas flows to the filter 5B, and the filter 5B continues to collect particulates.

During the regeneration process of the filter 5A as described above, the discharge pressure PP of the electric air pump 9 is detected, and in step 204 the discharge pressure PP of the electric air pump 9 is the minimum discharge pressure Pmin and the maximum during the normal regeneration process. It is determined whether or not it is within the discharge pressure Pmax. This is the control valve V
1, V2 determines whether or not the branch pipe 2A is normally closed. As shown in FIG. 3, when the control valves V1 and V2 both normally close the branch pipe 2A, the discharge pressure PP is P during the period from the regeneration start to the regeneration end of the filter 5A.
min ≦ PP ≦ Pmax. On the other hand, when PP <Pmin, the control valve V2 does not normally close the branch pipe 2A, the secondary air flows to the exhaust pipe 2D side without being supplied to the filter 5A, and the discharge pressure PP decreases. Status is considered, P
When P ≧ Pmax, the control valve V1 does not normally close the branch pipe 2A, and the exhaust gas may flow into the branch pipe 2A side and the discharge pressure PP may increase.

First, the control valves V1 and V2 are normally connected to the branch pipe 2.
The case where A is closed will be described. In this case, it is determined in step 205 whether the valve abnormality flag VAEF is "1", and when the control valves V1 and V2 are normal, VAEF =
Since it is "0", the routine proceeds to step 206, where it is judged whether or not the reproduction is ended, and thereafter, the processing from step 203 to step 206 is repeated for each predetermined interval until the reproduction is ended. In addition, the valve abnormality flav VAEF is previously
It is set to "0" and becomes "1" when any of the control valves V1 and V2 does not normally close the branch pipe 2A.

Next, a case where either one of the control valves V1 and V2 does not normally close the branch pipe 2A will be described.
In this case, in step 204 PP <Pmin or PP
≧ Pmax, and the routine proceeds to step 207. Step 20
In step 7, the valve abnormality lamp 12 is made to blink, and in step 208 the valve abnormality flag VAEF is set to "1". Then, in step 206, it is determined whether or not the reproduction is completed, and after a predetermined interval, the process returns to step 203. The control valve V
When an abnormality occurs in which either one of V1 and V2 does not normally close the branch pipe 2A, the valve abnormality flag VAEF becomes "1" in step 208, and then Pmin ≤ PP ≤ Pmax in step 204. However, since VAEF = "1" in step 205, step 2
Proceeding to 07, the valve abnormality lamp 12 continues to blink.

When the regeneration of the filter 5A is completed in this way, the routine proceeds from step 206 to step 209, and the exhaust gas passage is switched. That is, the control valves V1 and V2
Block the inlet side and outlet side of the branch pipe 2B with a check valve V
While keeping the valves V3 and V4 open, the valves V5 and V7 are closed and the valves V6 and V8 are opened. Then, in step 210, the secondary air from the electric air pump 9 is supplied to the filter 5B through the regeneration gas supply pipe 7, the heater HB is energized to burn the particulates in the filter 5B, and the combustion gas is discharged as combustion gas. It is discharged into the atmosphere through the pipe 8. At this time, the exhaust gas flows to the filter 5A, and the filter 5A collects particulates.

During the regeneration process of the filter 5B as described above, the discharge pressure PP of the electric air pump 9 is detected, and in step 211, as in the case of the filter 5A, the discharge pressure PP of the electric air pump 9 is normally regenerated. It is determined whether or not it is between the minimum discharge pressure Pmin and the maximum discharge pressure Pmax during processing. When the control valves V1 and V2 normally close the branch pipe 2B, it is determined in step 212 whether the valve abnormality flag VBEF is "1". If the control valves V1 and V2 are normal, the process proceeds to step 213. It is determined whether or not the reproduction is completed, and thereafter, the processing from step 211 to step 213 is repeated for each predetermined interval until the reproduction is completed.

When one of the control valves V1 and V2 does not normally close the branch pipe 2A, in step 211, PP
<Pmin or PP ≧ Pmax, and step 214
Proceed to. In step 214, the valve abnormality lamp 12 is made to blink, and in step 215, the valve abnormality flag VBEF is set.
Set to "1". Then, in step 213, it is determined whether or not the reproduction is completed, and after a predetermined interval, step 210
Return to. Even during the regeneration of the filter 5B, if an abnormality occurs in which either one of the control valves V1 and V2 does not normally close the branch pipe 2A, once during the regeneration, Pmin ≦ P in step 211.
Even when P ≦ Pmax, the routine proceeds to 214, where the valve abnormality lamp 12 continues to blink.

As described above, in the exhaust particle removing apparatus for the diesel engine of the present invention, since the abnormality of the exhaust control valve can be detected, the exhaust gas flows into the filter side during regeneration and the flow of the secondary air is changed. It is possible to reduce the risk of unburning due to the shortage of secondary air due to the obstruction. FIG. 4 shows a procedure of another embodiment of the control of the control device 100 in the exhaust particulate removal device of the diesel engine of the present invention. When the process of FIG. 4 is executed, in the exhaust particulate removal device 20 of the diesel engine of FIG. 1, the pressure sensors SP1 and SP2 are provided on the regeneration gas supply pipe 7 side and the combustion gas exhaust pipe 8 side of the filter 5A, respectively. It is necessary to provide pressure sensors SP3 and SP4 on the regeneration gas supply pipe 7 side and the combustion gas discharge pipe 8 side of the filter 5B, respectively. In this case, the detection values of the pressure sensors SP1 to SP4 are respectively P
From 1 to P4.

In this embodiment, the differential pressure PD is detected in step 401, and it is determined in step 402 whether it is the regeneration time. The determination of the regeneration timing is performed by the differential pressure sensor 10
The output value PD of is greater than or equal to the determination value. When it is not the reproduction time, step 401 is performed again after a predetermined interval.
At step 402, the differential pressure PD is detected, and the process of determining whether or not it is the regeneration time is repeated. On the other hand, step 4
When it is judged that the reproduction time is reached in step 02, step 403
Proceed to.

At step 403, the regeneration process of the filter 5A is executed. At the time of the regeneration process of the filter 5A, the control valve V
1, V2 block the inlet side and the outlet side of the branch pipe 2A, and the check valves V3, V4 and the open / close valves V5, V7 are opened. In this state, the secondary air from the electric air pump 9 is supplied to the filter 5A through the regeneration gas supply pipe 7 to energize the heater HA. The heater HA is energized to ignite and burn the particulates in the filter 5A, and the combustion gas is discharged into the atmosphere through the combustion gas discharge pipe 8. At this time, the exhaust gas flows to the filter 5B, and the filter 5B continues to collect particulates.

In step 404, it is determined whether or not one minute before the end of the reproduction process of the filter 5A. If one minute before the end of the reproduction process of the filter 5A, the process returns to step 403 after a predetermined interval, and the determination of step 404 is repeated. When it is determined in step 404 that one minute before the end of regeneration of the filter 5A, the routine proceeds to step 405, where the upstream / downstream differential pressure PA = P1-P2 of the filter 5A is detected, and the detected differential pressure PA is the maximum allowable at the end of regeneration. In step 406, it is determined whether the pressure difference is larger than the differential pressure PAmax. If PA ≦ PAmax, the routine proceeds to step 407, this time the differential pressure PA detected at step 405 is the minimum allowable differential pressure PAmi at the end of regeneration.
Determine if it is less than n.

If the filter 5A is normally regenerated and the control valves V1 and V2 are operating normally, step 40
No in 6 and NO in step 407, step 41
Go to 2. On the other hand, when the control valve V1 is not operating normally, the exhaust gas flows into the regeneration downstream side of the filter 5A, so that the pressure P2 increases and PA <PAmin. Further, when the control valve V2 is not operating normally, the secondary air flows out to the exhaust pipe 2D side, so the pressure P1 becomes low and P
A <PAmin. In this case, step 406
And NO in step 407, and YES in step 407, and the process proceeds to step 408. In step 408, the abnormal lamp 12 of the control valve is made to blink, and in step 409, the process of increasing the secondary air amount at the time of the next regeneration of the filter 5A is performed, and the process proceeds to step 412. In the process of step 409, the regeneration process is not normally performed because the current secondary air amount is too small regardless of which of the control valves V1 and V2 is abnormal. Therefore, the secondary air amount is increased at the next regeneration. It is for.

Further, when there is a large amount of unburned particulates in the filter 5A during the regeneration process of the filter 5A,
The differential pressure PA upstream and downstream of the filter 5A becomes larger than PAmax. In such a case, YE in step 406.
When S is reached, the routine proceeds to step 410, where the unburned residue abnormality lamp (not shown in FIG. 1, but provided similarly to the valve abnormality lamp 12) blinks. Then, in step 411, processing is performed to increase the electric power of the heater HA and the amount of secondary air when the filter 5A is regenerated next time, and the process proceeds to step 412.

In step 412, it is determined whether or not one minute has passed since it was determined in step 404 that the reproduction process was one minute before, and it is determined whether or not the reproduction process was completed. Step 412 is executed every predetermined interval until YES. Then, after YES in step 412, the flow path of the exhaust gas is switched in step 413. That is, the control valves V1 and V2 close the inlet side and the outlet side of the branch pipe 2B, and the check valves V3 and V
4 is left open, the on-off valves V5 and V7 are closed, and the on-off valve V
Open V6 and V8. Then, the secondary air from the electric air pump 9 is supplied to the filter 5B through the regeneration gas supply pipe 7, the heater HB is energized to burn the particulates in the filter 5B, and the combustion gas is discharged through the combustion gas discharge pipe 8. Discharge into the atmosphere. At this time, the exhaust gas flows to the filter 5A, and the filter 5A collects particulates.

The processes of steps 414 to 424 are the processes of the filter 5A of steps 403 to 413 described above executed on the filter 5B. In step 414, the reproduction process of the filter 5B is executed, and in step 415. One minute before the end of regeneration of the filter 5B, the differential pressure PB = P3-P4 at the upstream and downstream of the filter 5B is detected in step 416, and the detected differential pressure PB is larger than the maximum allowable differential pressure PBmax at the end of regeneration. Whether or not it is determined in step 417. When PB ≦ PBmax, the routine proceeds to step 418, this time the differential pressure PB detected at step 416 is the minimum allowable differential pressure PBmi at the end of regeneration.
Determine if it is less than n.

If the filter 5B is regenerated normally and the control valves V1 and V2 are operating normally, step 41
No in step 7 and NO in step 417, step 41
Go to 2. PB <P when the control valve V1 is not operating normally or when the control valve V2 is not operating normally
Bmin is reached, NO in step 417, step 418
Is YES and the process proceeds to step 419. Step 41
In step 9, the abnormal lamp 12 of the control valve is made to blink, and step 4
In step 20, the secondary air amount is increased when the filter 5B is regenerated next time, and the process proceeds to step 423.

During the reproduction process of the filter 5B, the filter 5B
If there are many unburned particles, PB> P
Since it is Bmax, YES is obtained in the step 417, the process proceeds to a step 421, and an unburned residue abnormality lamp (not shown in FIG. 1) is blinked. Then, in step 422, the electric power of the heater HB and the secondary air amount are increased when the filter 5B is regenerated next time, and the process proceeds to step 423.

In step 423, it is determined whether or not one minute has elapsed after the reproduction processing of the filter 5B was judged to be one minute before the reproduction processing of the filter 5B was completed in step 415.
Step 423 is executed at predetermined intervals until YES. After YES in step 423, the exhaust gas flow path is switched. That is, the control valves V1 and V2 are set to neutral 1, the check valves V3 and V4, and the open / close valves V5 to V8 are all closed, and the driving of the electric air pump 9 is stopped. This state is a state where the filters 5A and 5B shown in FIG.

In the embodiment described above, the abnormality of the control valve and the unburned residue at the time of filter regeneration can be detected to notify the occupant, and when detected, appropriate processing can be taken at the time of the next regeneration. it can. The exhaust gas particulate remover 20 for the diesel engine in the above-described embodiment uses the filters 5A and 5B to simultaneously collect the particulates in the exhaust gas, and the secondary air flows in the opposite direction to the flow of the exhaust gas during regeneration. Although it is of the simultaneous trapping type and the reverse flow alternation regenerating type in which the filters 5A and 5B are alternately regenerated by flowing from the above, the present invention is limited to the exhaust particulate removing device of the diesel engine of this simultaneous trapping type, the reverse flow alternating regeneration type. Not a thing. For example, as shown in FIG. 5, the filters 5A and 5B are used to simultaneously collect particulates in the exhaust gas, and at the time of regeneration, secondary air is caused to flow from the same direction as the flow of the exhaust gas to filter the filters 5A and 5B. Exhaust particulate removal device 30 of diesel engine of simultaneous collection and forward flow alternating regeneration that alternately regenerates,
The present invention can also be applied to an exhaust particulate removal device 40 of a diesel engine of a type in which a filter is provided only on one of the branch pipes 2A and 2B as shown in FIG.

In the exhaust particulate matter removing devices 30 and 40 of the diesel engine shown in FIGS. 5 and 6, the same components as those of the exhaust particulate matter removing device 20 of the diesel engine are designated by the same reference numerals. Therefore, the description of the configuration is omitted. FIG. 7 is a control valve V in the exhaust particulate removal device 20, 30 of the diesel engine shown in FIGS.
1 shows an example of a configuration of No. 1. When the opening / closing operation of the control valve V1 is performed by a diaphragm device that uses negative pressure and spring force, that is, negative pressure is applied to the diaphragm to suck the rod, and when no negative pressure is applied, the rod is projected by the force of the spring. When the diaphragm device is used, the suction force of the rod due to the negative pressure is smaller than the thrust force of the rod due to the spring. Therefore, the diaphragm 71 and the spring 7 that biases the diaphragm 71
2. When the diaphragm device 70 provided with the rod 73 protruding from the diaphragm 71 is used to drive the control valve V1, the branch pipes 2A, 2B and the diaphragm device 70 are arranged as shown in FIG. 7 (a). . However, illustration of the regeneration gas supply pipe 7 or the combustion gas discharge pipe 8 is omitted.

That is, the branch pipe 2B is branched from the branch pipe 2A so as to be orthogonal to each other, and the control valve V1 provided at the branch portion a is shown in FIG.
As shown in (a), the control valve V1 closes the branch pipe 2A while the diaphragm 71 is sucked by the negative pressure, and the diaphragm 71 is biased by the spring force as shown in FIG. 7 (b). The control valve V1 is configured to close the branch pipe 2B. With this configuration, in the state of FIG. 7 (a), the control valve V1 biases the branch pipe 2A in the valve closing direction by the pressure of the exhaust gas, so that the valve closing force of the branch pipe 2A due to the negative pressure is weak. Can be supplemented.

FIG. 8 shows another embodiment of the structure of the control valve V1 in the exhaust particle removing devices 20 and 30 of the diesel engine shown in FIGS. As described above, when the opening / closing operation of the control valve V1 is performed by the diaphragm device 70 including the diaphragm 71, the spring 72 for urging the diaphragm 71, and the rod 73 projecting from the diaphragm 71, the rod 73 by negative pressure is used. The attraction force is smaller than the thrust output of the rod 73 by the spring 72.
Therefore, as shown in FIGS. 8 (a) and 8 (b), the spring 72
The branch pipe 2A for the first regeneration is closed by the urging force of 1 and the branch pipe 2B for the later regeneration is closed by the force of the negative pressure. However, illustration of the regeneration gas supply pipe 7 or the combustion gas discharge pipe 8 is omitted.

In this way, the amount of exhaust gas leaking from the control valve V1 to the filter side during regeneration is larger due to the negative pressure shown in FIG. 8 (b). However, in an exhaust particulate removal device for a diesel engine that performs simultaneous collection and alternate regeneration, the amount of particulates collected on the side of the filter 5A that performs regeneration first is small, so the control valve V1 uses a spring force during regeneration of the filter 5A. If the branch pipe 2A is securely closed, 2
The next air can be made to flow according to the setting and can be regenerated satisfactorily.
On the other hand, the filter 5B, which is to be reproduced later, has the filter 5
Since the amount of collected particulates is large during the regeneration of A as well, the unburned residue is generated even if the exhaust gas slightly flows in from the control valve V1 during regeneration and the amount of secondary air decreases. Hard to do.

FIG. 9 shows an embodiment in which the exhaust particulate removal device for a diesel engine which performs simultaneous collection has a curved exhaust pipe 2 upstream of the branch portion a of the branch pipes 2A and 2B. . In such a case, as shown in FIG. 9 (c), a large amount of exhaust gas flowing through the exhaust pipe 2 flows into the branch pipe 2B outside the curved portion of the exhaust pipe 2, and is collected by the filter 5B at the time of simultaneous collection. The amount of particulates that are generated increases. Therefore, as shown in FIGS. 9 (a) and 9 (b), the branch pipe 2A,
A honeycomb rectifying device 90 having a large number of partition walls is provided on the upstream side of the branch portion a of 2B. Since a large number of rectangular parallelepiped passages (cells) surrounded by partition walls are provided in parallel inside the rectifying device 90, the flow of the exhaust gas is corrected by passing through the cells to rectify the flow. Device 90
When you leave, the flow will be parallel. As a result, filter 5
The collection amount and collection distribution of A and 5B can be made equal.

[0050]

As described above, according to the exhaust particle removing apparatus for a diesel engine of the present invention, the exhaust cutoff valve is used during the regeneration process of the filter so that the exhaust gas does not flow into the filter being regenerated. In the conventional exhaust gas particulate remover for a diesel engine, it is possible to detect an abnormality in the exhaust gas cutoff valve during regeneration of the filter.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an embodiment of an exhaust particulate removal apparatus of the simultaneous collection and reverse flow alternate regeneration dual filter type of the present invention.

FIG. 2 is a flowchart showing an example of a filter regeneration processing procedure of the control circuit of FIG.

FIG. 3 is a diagram showing a discharge pressure of an electric air pump during filter regeneration.

FIG. 4 is a flowchart showing another embodiment of the filter regeneration processing procedure of the control circuit of FIG.

FIG. 5 is a diagram showing a schematic configuration of an embodiment of an exhaust particulate removal device of the simultaneous collection and forward flow alternate regeneration dual filter type of the present invention.

FIG. 6 is a diagram showing a schematic configuration of an embodiment of a backflow regeneration single filter type exhaust particulate removal device of the present invention.

7 (a) and 7 (b) are explanatory views showing a configuration and a switching operation of an embodiment when a diaphragm type actuator is used to drive the first control valve.

8 (a) and 8 (b) are explanatory views showing a configuration and a switching operation of another embodiment when a diaphragm type actuator is used to drive the first control valve.

9 (a) is a partial configuration diagram showing a configuration in the case where a rectifying device is used in an exhaust particulate removing device of a diesel engine of the present invention, and FIG. 9 (b) shows a configuration of a rectifying device alone used in (a). FIG. 6 (c) is a perspective view showing the flow of exhaust gas in the conventional exhaust gas particulate removal device for a dual filter type diesel engine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Diesel engine 2 ... Exhaust pipe 2A, 2B ... Branch pipe 5A, 5B ... Filter 7 ... Regeneration gas supply pipe 8 ... Combustion gas exhaust pipe 9 ... Air pump 10 ... Differential pressure sensor 12 ... Valve abnormal lamp 70 ... Diaphragm type actuator 71 ... Diaphragm 72 ... Spring 73 ... Rod 90 ... Rectifier 100 ... Control circuit a ... Branching part b ... Junction part HA, HB ... Electric heater V1 ... First control valve V2 ... Second control valve V3, V4 ... Check Valves V5-V8 ... Open / close valves

Claims (1)

[Claims] 1. A state in which particulates in exhaust gas are collected by a filter provided in an exhaust passage of an engine, and an exhaust control valve cuts off the inflow of exhaust gas into the filter where particulates are collected when the filter is regenerated. In the exhaust particulate removal device of the diesel engine that ignites the particulates collected by the filter and supplies the regeneration gas from the regeneration gas supply means, the discharge pressure of the regeneration gas supply means, or the exhaust control An exhaust particulate removal device for a diesel engine, comprising: a means for detecting a pressure on the downstream side of the valve; and a means for determining an abnormality of the exhaust control valve based on the detected pressure value.