JPH09151807A - Abnormality detecting device for exhaust gas recirculating device of internal combusting engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly detect abnormality in draft resistance of an atmospheric pressure introducing port of an electronic vacuum regulating(EVR) valve, which selectively introduces the negative pressure/atmospheric pressure into an exhaust gas recirculating(EGR) valve. SOLUTION: An E.G.R. device 16 is provided with an E.G.R valve 18 and an EVR valve 19. The E.G.R. valve 18 is opened/closed by the negative pressure and atmospheric pressure, which is supplied selectively. The EVR valve 19 is provided with a port 19a, which communicates with the E.G.R. valve 18, a port 19b for introducing the negative pressure, and a port 19 c for introducing the atmospheric pressure. A filter 22 is installed in the port 19c. To open the E.G.R. valve 18, both ports 19a and 19b communicated with each other so that the negative pressure is introduced into the E.G.R. valve 18. To close the E.G.R. valve 18, both ports 19a and 19c are communicate with each other so that the atmospheric pressure is introduced into the E.G.R. valve 18. An electronic controlling unit(ECU) 41 measures the time required for the E.G.R. valve 18 to be closed from its opened state, and, if the time measured is larger than a prescribed value, it is judged that the draft resistance of the filter 22 is abnormally large.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas recirculation system for recirculating a part of exhaust gas discharged from an internal combustion engine to an exhaust passage to the intake passage and returning it to the internal combustion engine. More specifically, in an exhaust gas recirculation device equipped with a negative pressure operating valve that operates by negative pressure and atmospheric pressure to control the recirculation of the exhaust gas, an abnormality relating to the responsiveness of the negative pressure operating valve is detected. The present invention relates to an abnormality detection device for an exhaust gas recirculation device for an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally known exhaust gas recirculation (exhaust gas recirculation: E) used in internal combustion engines such as diesel engines and gasoline engines.
GR) device. This EGR device reduces nitrogen oxides (NOx) contained in the exhaust gas by recirculating a part of the exhaust gas discharged from the combustion chamber to the exhaust passage and returning it to the combustion chamber again. As an EGR device of this type, there is a device that can control the presence or absence of EGR according to the operating state of the internal combustion engine.

Japanese Unexamined Patent Publication No. 7-19127 discloses a diesel engine equipped with an EGR amount adjustable E
A GR device is disclosed. As shown in FIG. 10, this EGR
The device has an E for flowing exhaust gas from the exhaust passage to the intake passage.
A GR passage 51 and an EGR valve 52 for controlling the EGR amount flowing through the EGR passage 51 are provided. This EGR
The valve 52 is a diaphragm valve that selectively opens and closes by selectively introducing negative pressure and atmospheric pressure as operating pressure.
The EGR valve 52 includes a housing 52b having a diaphragm 52a built therein, a valve body 52c fixed to the diaphragm 52a, and a spring 52d for urging the valve body 52c in a direction in which the EGR passage 51 is closed. The EGR device further includes an electrically controlled electric vacuum regulator (E) for adjusting the negative pressure and the atmospheric pressure to be introduced into the housing 52b.
VR) valve 53 is provided.

The EVR valve 53 is a three-way valve having three ports, and has an output port 53a communicating with the housing 52b and a negative pressure port 53b communicating with a negative pressure supply source.
And an atmosphere port 53c communicating with the atmosphere. Generally, a filter 54 is provided at the atmospheric port 53c.
The filter 54 prevents dust and muddy water from entering the EVR valve 53 through the atmospheric port 53c. EVR valve 53
Is electrically turned on, the output port 53a and the negative pressure port 53b communicate with each other and the housing 52b
Negative pressure is introduced into. As a result, the diaphragm 52a
Is displaced upward against the biasing force of the spring 52d, the valve body 52c moves upward, and the EGR passage 51 is opened. on the other hand,
By electrically turning off the EVR valve 53, the output port 53a and the atmospheric port 53c communicate with each other, and atmospheric pressure is introduced into the housing 52b. As a result, the diaphragm 52a is displaced downward by the biasing force of the spring 52d, the valve body 52c moves downward, and the EGR passage 51 is closed.

Here, the responsiveness of EGR control in an internal combustion engine has a considerable influence on emissions. EGR
The responsiveness of the control is the responsiveness of the operation of the EGR valve 52, and further the EV
It depends on the operation response of the R valve 53. Therefore, in order to improve the responsiveness of EGR control, mechanical improvement of both valves 52 and 53 and improvement of a control method of EVR valve 53 are being advanced.

[0006]

However, in the above-mentioned conventional EGR device, the filter 5 provided in the EVR valve 53 is provided.
4 is clogged with dust, muddy water, etc.
The ventilation resistance of No. 4 increases, and the ventilation resistance of the atmosphere port 53c tends to become abnormally large. If the ventilation resistance of the filter 54 increases, the responsiveness of the pressure change from the negative pressure to the atmospheric pressure at the output port 53a deteriorates when the EVR valve 53 is turned off. This causes a delay in the introduction of atmospheric pressure to be introduced into the housing 52b to close the EGR valve 52. Therefore, despite the mechanical improvement of both valves 52 and 53, the operating response of the EGR valve 52, that is, the closing response, deteriorates. As a result, the emission of the internal combustion engine may deteriorate.

The graph of FIG. 11 shows the relationship between the response time of pressure change at the output port 53a and the ventilation resistance of the filter 54 when the EVR valve 53 is turned off. "T1
1, R1 ”indicates the characteristics of the new filter 54.
“T12, R2” indicates the characteristic of the filter 54 in a normal state to the extent that the operation response of the EGR valve 52 is not adversely affected. On the other hand, "T13, R3" indicates the characteristics of the filter 54 at the time of abnormality that adversely affects the operation response of the EGR valve 52. As can be seen from this graph, there is a clear difference in order between the response time and the ventilation resistance between the normal time and the abnormal time.

As another EGR device, it is possible to directly connect the EVR valve to the intake passage of the internal combustion engine without providing a filter on the atmospheric port. But,
Even with this configuration, when the ventilation resistance in the intake passage abnormally increases, the ventilation resistance related to the atmospheric port of the EVR valve may abnormally increase.

The above-mentioned abnormality in ventilation resistance is unlikely to appear as a change in appearance, so that it is extremely difficult for a person to recognize it, and at present, it has been overlooked. The present invention has been made in view of the above-mentioned circumstances, and an object thereof is a negative pressure regulating valve (EVR valve) that selectively guides a negative pressure for operation and an atmospheric pressure to a negative pressure operating valve (EGR valve). In an EGR device for an internal combustion engine having the above, it is possible to properly detect an abnormality in the ventilation resistance related to the atmospheric pressure introducing port of the negative pressure adjusting valve by monitoring the operation response of the negative pressure operating valve. An object of the present invention is to provide an abnormality detection device for an exhaust gas recirculation device for an internal combustion engine.

[0010]

In order to achieve the above object, in the invention described in claim 1, as shown in FIG. 1, one of the exhaust gas exhausted from the internal combustion engine M1 to the exhaust passage M2. Part is recirculated to the intake passage M3 and the internal combustion engine M1
Is an exhaust gas recirculation device adapted to return to the negative pressure operating valve M4 that selectively opens and closes based on the negative pressure and the atmospheric pressure that are selectively supplied to control the recirculation of the exhaust gas.
And a first port M5 communicating with the negative pressure operated valve M4,
It has a second port M7 communicating with a negative pressure source M6 and a third port M8 communicating with the atmosphere, respectively, and connects the first and second ports M5, M7 to each other to open the negative pressure operating valve M4. The first and third ports M5 and M for communicating the negative pressure to the negative pressure operating valve M4 and closing the negative pressure operating valve M4.
In the abnormality detection device for an exhaust gas recirculation device, which includes a negative pressure adjusting valve M9 configured to communicate 8 with each other to guide the atmospheric pressure to the negative pressure operating valve M4, a closing response of the negative pressure operating valve M4. The measuring means M10 for measuring the state and the ventilation resistance related to the third port M8 of the negative pressure adjusting valve M9 is abnormal when the measured valve closing response state becomes worse than a predetermined reference valve closing response state. It is intended to further include an abnormality determination means M11 for determining that it is large.

According to the above construction, the negative pressure control valve M4 is opened, and the first and third ports M5 and M8 of the negative pressure control valve M9 are made to communicate with each other so that the negative pressure control valve M4 has a large pressure. The atmospheric pressure is introduced to close the negative pressure operation valve M4. Here, when the ventilation resistance of the third port M8 is abnormally increased due to clogging or the like, the introduction of atmospheric pressure to the negative pressure operating valve M4 is delayed. Therefore, the negative pressure operated valve M4
The valve closing response state of is worse than the standard response state. The measuring means M10 measures this valve closing response state, and the abnormality determining means M11 indicates to the third port M8 of the negative pressure regulating valve M9 when the measured valve closing response state becomes worse than the reference valve closing response state. It is determined that the ventilation resistance is abnormally large.

Here, the deterioration of the valve closing response state of the negative pressure operating valve M4 is caused by the delay in the introduction of atmospheric pressure into the valve M4, and the delay is the negative pressure adjusting valve M9 at the first port M5. Is connected to the second port M7 to the third port M8
When it is switched to, the response delay until the atmospheric pressure acts from the third port M8 to the first port M5, and eventually the ventilation resistance related to the third port M8. Therefore, even if the ventilation resistance related to the third port M8 is unknowingly and abnormally increased, that is not the case.
It is determined without omission based on the operating state of.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment in which an abnormality detecting device for an exhaust gas recirculation device for an internal combustion engine according to the present invention is embodied in a diesel engine of an automobile will be described in detail below with reference to the drawings. To do.

FIG. 2 is a schematic diagram showing the diesel engine system of this embodiment. An engine 1 as an internal combustion engine has a plurality of cylinders including a combustion chamber 2. In the intake stroke of the engine 1, when the intake port 3 provided for each cylinder is opened by the intake valve 4, the outside air drawn into the intake passage 6 through the air cleaner 5 flows into each combustion chamber 2. The fuel injection nozzle 7 provided for each cylinder injects the fuel pumped from the fuel injection pump 8 into each combustion chamber 2. In the compression stroke of the engine 1, the fuel and the outside air in each combustion chamber 2 are pressurized by the upward movement of the piston 9 and explode / combust, so that the piston 9 moves downward and the crankshaft 10 rotates. Driving force is obtained. In the exhaust stroke of the engine 1, the exhaust port 11 provided for each cylinder is opened by the exhaust valve 12, whereby the exhaust gas generated in each combustion chamber 2 is led to the exhaust passage 13 and further discharged to the outside. .

The throttle valve 14 provided in the intake passage 6 operates in conjunction with the operation of the accelerator pedal 15 to selectively open and close the intake passage 6. The operation of the throttle valve 14 adjusts the amount Q of air taken into the intake passage 6.

The exhaust gas recirculation (EGR) device 16 recirculates a part of the exhaust gas discharged from each combustion chamber 2 to the exhaust passage 13 to the intake passage 6 and returns it to each combustion chamber 2. This E
The GR device 16 includes an EGR passage 17 for flowing a part of the exhaust gas from the exhaust passage 13 to the intake passage 6, and an EGR valve 18 for controlling the amount of EGR flowing through the passage 17. The EGR valve 18 as the negative pressure operating valve of the present invention selectively introduces negative pressure and atmospheric pressure as operating pressures,
It is a diaphragm valve that selectively opens and closes. EGR valve 18
Is a housing 18b containing a diaphragm 18a
A valve body 18c fixed to the diaphragm 18a; and a spring 18d for urging the valve body 18c in the direction in which the EGR passage 17 is closed. The EGR device 16 is
Furthermore, an electrically controlled electric coil for adjusting the negative pressure and the atmospheric pressure to be introduced into the housing 18b.
A vacuum regulating (EVR) valve 19 is provided.

The EVR valve 19 as the negative pressure adjusting valve of the present invention
Is a three-way valve having three ports 19a, 19b, 19c. The EVR valve 19 is a housing 18 of the EGR valve 18.
The output port 19a as the first port of the present invention communicating with b through the communication passage 20 and the negative pressure as the second port of the present invention communicating with the vacuum pump 21 as the source of the negative pressure. The port 19b and the atmospheric port 19c as the third port of the present invention, which communicates with the atmosphere via the filter 22, are provided. The filter 22 prevents dust and muddy water from entering the EVR valve 19 through the atmospheric port 19c.

When the EVR valve 19 is electrically turned on, the output port 19a and the negative pressure port 19b communicate with each other and a negative pressure is introduced into the housing 18b of the EGR valve 18. As a result, in the EGR valve 18, the diaphragm 18a is displaced upward against the biasing force of the spring 18d, the valve body 18c is moved upward, and the EGR passage 17 is opened. That is, the EGR valve 18 opens and the EGR passage 17
Exhaust gas flows, and the exhaust gas is recirculated to the intake passage 6 and returned to each combustion chamber 2. That is, EGR is executed. On the other hand, when the EVR valve 19 is electrically turned off, the output port 19a and the atmospheric port 19c communicate with each other, and atmospheric pressure is introduced into the housing 18b. As a result, in the EGR valve 18, the diaphragm 18a is displaced downward by the urging force of the spring 18d, and the valve body 1
8c moves downward and the EGR passage 17 is closed. That is,
The EGR valve 18 is closed and the flow of exhaust gas in the EGR passage 17 is stopped. That is, the execution of EGR is stopped.

The well-known distribution type fuel injection pump 8 supplies the fuel to be burned in each combustion chamber 2 to each injection nozzle 7. The injection pump 8 compresses the fuel stored in a fuel tank (not shown) to a high pressure, and sends it to each injection nozzle 7 with a required amount and timing. Each injection nozzle 7 operates based on the pressure of the fuel to be pumped, and injects the fuel into the corresponding combustion chamber 2. A governor (not shown) built in the injection pump 8 adjusts the amount of fuel discharged from the pump 8 each time. Similarly, a timer (not shown) incorporated in the injection pump 8 adjusts the discharge start timing and the discharge end timing of the fuel from the pump 8, respectively. These governors and timers are electrically controlled. The drive shaft 8a of the injection pump 8 is connected to the crankshaft 10 of the engine 1. Therefore, the injection pump 8
Are driven in conjunction with the operation of the engine 1.

The air flow meter 31 provided adjacent to the air cleaner 5 is provided with an air quantity Q sucked into the intake passage 6.
Is detected and a signal corresponding to the amount is output. The intake air temperature sensor 32 provided adjacent to the air flow meter 31
Temperature T of intake air (intake air temperature) T
HA is detected and a signal corresponding to the temperature is output. A throttle sensor 33 provided in the vicinity of the throttle valve 14 detects the opening of the valve 14 as an accelerator opening ACCP as an operation amount of the accelerator pedal 15, and outputs a signal corresponding to the opening. The sensor 33 includes a well-known idle switch (not shown). The idle switch is turned on and outputs an idle signal IDL when the throttle valve 14 is fully closed, that is, when the accelerator pedal 15 is not operated. The intake pressure sensor 34 provided in the intake passage 6 detects the intake pressure PM in the intake passage 6 and outputs a signal according to the pressure. The rotation speed sensor 35 provided in the injection pump 8 indirectly detects the rotation speed (engine rotation speed) NE of the crankshaft 10 based on the rotation of the drive shaft 8a,
The signal according to the speed is output.

On the other hand, the pressure sensor 36 provided in the communication passage 20 between the EGR valve 18 and the EVR valve 19 detects the internal pressure PH of the housing 18b and outputs a signal corresponding to the pressure.

A warning lamp 30 provided on the driver's seat (not shown) of the automobile operates to notify the abnormality of the EGR device 16. An electronic control unit (ECU) 41, which constitutes the measuring means and the abnormality determining means of the present invention, inputs signals output from the various sensors 31 to 36 described above. EC
U41 is based on these input signals, the injection pump 8, E
It controls the VR valve 19 and the warning lamp 30, respectively.

The ECU 41 is a central processing unit (CPU) 4
2. Read only memory (ROM) 43, random access memory (RAM) 44 and backup RAM 45
Is provided. The ECU 41 constitutes a logical operation circuit in which these units 42 to 45, an external input circuit 46, an external output circuit 47 and the like are connected by a bus 48. Where CP
U42 has both the function of arithmetic control and the function of a counter. The ROM 43 stores a predetermined control program and the like in advance. The RAM 43 temporarily stores the calculation result of the CPU 43 and the like. The backup RAM 45 stores previously stored data. The external input circuit 46 includes a buffer, a waveform shaping circuit, an A / D converter, and the like. The external output circuit 47 includes a drive circuit and the like. Various sensors 31 to 36 are external input circuits 46.
Connected to. Each member 8, 19, 30 is an external output circuit 4
7 is connected.

The CPU 42 reads the signals from the various sensors 31 to 36 input via the external input circuit 46 as input values. Based on these input values, the CPU 42 controls each member 8, 19, 30 and the like in order to execute fuel injection control, EGR control, and abnormality detection control related to the EGR device.

Here, the fuel injection control is to control the amount and timing of the fuel discharged from the injection pump 8 according to the operating state of the engine 1. What is EGR control?
Similarly, by controlling the EVR valve 19 according to the operating state of the engine 1, the EGR valve 18 is operated to control the EGR amount.

Next, of the various controls executed by the ECU 41, the processing contents of the EGR control and the abnormality detection control relating to the EGR device 16 will be described. Figures 4 and 5 described later
The ROM 43 stores in advance control programs and the like relating to various routines shown in the flowchart of FIG.

FIG. 4 shows "EG" for executing EGR control.
5 is a flowchart showing an "R control routine". ECU
41 periodically executes this routine at predetermined time intervals. First, at step 100, the ECU 41 reads the values of the intake air amount Q, the engine rotation speed NE, and the internal pressure PH, respectively, based on the detection signals of the sensors 31, 35, 36.

In step 110, the ECU 41 determines, based on the values of both parameters Q and NE, whether or not the condition for executing EGR is satisfied for the operating state of the engine 1. If this execution condition is not satisfied, E
The CU 41 shifts the processing to step 120.

At step 120, the ECU 41 sets E
In order to stop the GR, the EVR valve 19 is turned off to close the EGR valve 18. At the same time, the ECU
Reference numeral 41 sets the execution flag XFEGR of EGR to "0", and thereafter ends the processing once.

On the other hand, if the execution condition is satisfied in step 110, the ECU 41 executes the process in step 13
Move to 0. In step 130, the ECU 41 turns on the EVR valve 19 to execute the EGR.
The R valve 18 is opened. In this embodiment, the ECU 41
Fully opens the EGR valve 18. At the same time, the ECU 4
1 sets the execution flag XFEGR of EGR to "1". In this embodiment, the ECU 41 that executes the processing of steps 100 to 130 corresponds to EGR control means for controlling the EGR according to the operating state of the engine 1. In this way, the EGR is performed, so that each combustion chamber 2
A part of the exhaust gas is returned to the combustion chamber 2 to improve combustion, nitrogen oxide (NOx) contained in the exhaust gas discharged from each combustion chamber 2 is reduced, and emission is improved. To be

Next, at step 140, the ECU
Reference numeral 41 determines whether or not the value of the internal pressure PH read this time is equal to or greater than a predetermined reference value P1. Here, assuming that the internal pressure PH and the reference value P1 respectively indicate negative pressure, the ECU 41 compares the magnitudes of negative pressure. Here, when the value of the internal pressure PH is smaller than the reference value P1, the EGR
The negative pressure introduced into the housing 18b of the valve 18 will be relatively small. Therefore, the ECU 41 determines that the EGR valve 1
Assuming that 8 is not fully open, step 1
Move to 50. In step 150, the ECU 41
Sets that the inspection flag XFFC is set to "0" and that the subsequent processing is once terminated, assuming that the inspection regarding the ventilation resistance of the filter 22 of the EVR valve 19 is not particularly performed.

On the other hand, in step 140, when the value of the internal pressure PH is not less than the reference value P1, the negative pressure similarly introduced into the housing 18b is relatively large.
Assuming that the EGR valve 18 is fully open, the ECU 4
1 shifts the processing to step 160. Step 160
At 41, the ECU 41 sets the inspection flag XFFC to "1" to inspect the filter 22, and then ends the subsequent processing.

Therefore, according to the processing of this routine, E
Only when the GR is being performed and the EGR valve 18 is fully opened, the inspection of the filter 22 is permitted. In this embodiment, the ECU 41 that executes the processing of steps 140 to 160 uses the filter 22 of the EVR valve 19.
It corresponds to the inspection determination means for determining whether or not to permit the inspection regarding the ventilation resistance of.

FIG. 5 shows the above flags XFEGR and XFF.
An abnormality of the EGR device 16 based on C, particularly the filter 22
5 is a flowchart showing an "abnormality detection routine" for detecting an abnormality related to the above. The ECU 41 periodically executes this routine at predetermined time intervals.

First, at step 200, the ECU 41
Determines whether the inspection flag XFFC is "1". Here, when the flag XFFC is “0”, the ECU 41 determines that the inspection of the filter 22 is not to be performed, and the process proceeds to step 210. In step 210, the ECU 41 resets the value of the clocked value CFC for inspection to "0" and temporarily ends the subsequent processing.

On the other hand, if the check flag XFFC is "1" in step 200, the ECU 41 further determines in step 220 whether the execution flag XFEGR is "0". Here, when the flag XFEGR is "1", since EGR is being executed, the EC
The U41 executes the process of step 210 and once ends the subsequent processes. When the flag XFEGR is "0", the inspection of the filter 22 is permitted, that is, EGR.
Assuming that the valve 18 starts to close from the fully open state, the ECU
41 shifts the processing to step 230.

At step 230, the ECU 41 determines that E
Time required from the start of closing the GR valve 18, that is, the EGR valve 1
The timer value CFC reflecting the valve closing response state of 8 is incremented by "1".

Next, at step 240, the ECU
Reference numeral 41 determines whether or not the measured value CFC is greater than or equal to a predetermined reference value T1. This reference value T1 indicates that the ventilation resistance of the filter 22 is abnormally large due to the poor clogging of the filter 22, and is a value experimentally determined in advance. Here, when the measured value CFC is smaller than the reference value T1, the ECU 41 shifts the processing to step 250.

At step 250, the ECU 41 determines whether or not the value of the internal pressure PH is less than or equal to a predetermined reference value P2. Here, when the value of the internal pressure PH is larger than the reference value P2, the negative pressure introduced into the housing 18b is relatively large. Therefore, the ECU 41 determines that the EG
Assuming that the R valve 18 is not sufficiently closed, the subsequent processing is once ended.

On the other hand, the value of the internal pressure PH is the reference value P.
When it is 2 or less, the negative pressure introduced into the housing 18b is sufficiently small. Therefore, the EGR valve 18 is sufficiently closed before the measured value CFC reaches the reference value T1, and the ventilation resistance of the filter 22 connected to the atmospheric port 19c of the EVR valve 19 is sufficiently small. Therefore, the ECU 41 determines that the filter 22 is not badly clogged, that is, the ventilation resistance of the filter 22 is not abnormally large, and the process proceeds to step 260.

In step 260, the ECU 41 resets the inspection flag XFFC to "0". Next, in step 261, the ECU 41 turns off the warning lamp 30. Further, in step 262, the ECU 41
Backups the normal code indicating that the filter 22 is normal and the EGR valve 18 closing response is normal.
The data is stored in the AM 45, and the subsequent processing is temporarily terminated.

On the other hand, in step 240, the measured value C
When FC is equal to or greater than the reference value T1, the measured value CFC is equal to the reference value T
Even if the value reaches 1, the EGR valve 18 is not fully closed. Therefore, the ECU 41 determines that the filter 22 is badly clogged and the ventilation resistance is abnormally large, and the process proceeds to step 270.

At step 270, the ECU 41 resets the inspection flag XFFC to "0". Next, in step 271, the ECU 41 turns on the warning lamp 30 to notify the abnormality of the filter 22. Furthermore,
In step 272, the ECU 41 determines that the closing responsiveness of the EGR valve 18 is abnormal due to the abnormality of the filter 22, stores an abnormality code indicating this in the backup RAM 45, and temporarily ends the subsequent processing.

In this embodiment, the above steps 220, 2
The ECU 41 that executes the process of 30 corresponds to the measuring means of the present invention for measuring the valve closing response state of the EGR valve 18. ECU 41 that executes the processing of step 240
Corresponds to the abnormality determining means of the present invention. That is, the ECU 4
1 is the time value C that reflects the closing response state of the EGR valve 18.
When FC is larger than the reference value T1, it is determined that the ventilation resistance of the filter 22 related to the atmospheric port 19c of the EVR valve 19 is abnormally large. Step 2
ECU 41 and warning lamp 30 for executing the processing of 71
Corresponds to an informing unit for informing an abnormality of the filter 22. ECU 41 that executes the processing of step 272
Corresponds to a recording unit for recording the abnormality of the filter 22.

The behaviors of the parameters PH, XFEGR and CFC are shown in the timing charts of FIGS. 3 (a), 3 (b) and 3 (c). With the EGR valve 18 fully open, at time t
When the EGR is stopped at 0 and the execution flag XFEGR changes from "1" to "0", the addition of the clock value CFC is started.

After that, when the ventilation resistance of the filter 22 is normal, at time t2 and t3, the value of the internal pressure PH falls below the reference value P2 before the measured value CFC reaches the reference value T1. It is determined that the filter 22 is normal.

On the other hand, when the ventilation resistance of the filter 22 is abnormal, at time t4, the measured value CFC is changed to the reference value T1.
Since the value of the internal pressure PH exceeds the reference value P2 even when the temperature reaches, it is determined that the filter 22 is abnormal at this point.

As described above, according to the configuration of this embodiment, the EVR valve 19 is opened while the EGR valve 18 is open.
By connecting the output port 19a and the atmospheric port 19c to each other, the atmospheric pressure is introduced into the housing 18b of the EGR valve 18 and the valve 18 is closed. Here, when the ventilation resistance of the filter 22 connected to the atmosphere port 19c is abnormally increased due to bad clogging, FIG.
As indicated by the broken line in (a), the introduction of atmospheric pressure into the housing 18b is delayed. Therefore, the time required to close the EGR valve 18 from the open state becomes longer than the standard value.

The ECU 41 uses this required time as the clock value CFC.
The measured value CFC is compared with a predetermined reference value T1. When the measured value CFC is larger than the reference value T1, the ECU 41 determines that the EVR valve 19 has the atmospheric port 19
It is determined that the ventilation resistance of the filter 22 related to c is abnormally large.

Here, the time required to close the EGR valve 18 is due to the delay in the introduction of atmospheric pressure into the housing 18b. The introduction delay is caused when the communication destination of the output 19a in the EVR valve 19 is switched from the negative pressure port 19b to the atmosphere port 19c.
This is due to the response delay until the atmospheric pressure acts on the output port 19a from c, and further to the abnormal ventilation resistance of the filter 22 related to the atmospheric port 19c.

Therefore, even if the ventilation resistance of the filter 22 related to the atmospheric port 19c is abnormally increased without being known, it can be determined without fail by monitoring the operation response of the EGR valve 18. As a result, EVR valve 1
The abnormality of the ventilation resistance of the filter 22 related to the atmosphere port 19c of No. 9 can be detected easily and properly.

According to this embodiment, since the warning lamp 30 is turned on when the abnormality of the ventilation resistance of the filter 22 is detected, the driver or the like can immediately know the abnormality. Therefore, the filter 22 is notified of the abnormality.
Can be replaced appropriately to restore the closing response of the EGR valve 18 to a normal state. In this sense,
It is possible to deal with the deterioration of the emission of the engine 1 early.

According to this embodiment, when the abnormality of the ventilation resistance of the filter 22 is detected, the fact is stored in the backup RAM 45 by the abnormality code. Therefore, at the time of checking the engine 1, the operator makes a backup R
By reading the data in the AM 45, the history regarding the abnormality of the filter 22 can be confirmed. In this sense, the filter 22 can be replaced in a timely manner, and the deterioration of the emission of the engine 1 can be dealt with earlier.

Next, a second embodiment which embodies an abnormality detecting device for an exhaust gas recirculation device for an internal combustion engine according to the present invention will be described in detail with reference to the drawings. In the configuration of this embodiment, the same members as those in the configuration of the first embodiment are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, points that are particularly different from the first embodiment will be mainly described.

FIG. 6 is a schematic configuration diagram showing the diesel engine system of this embodiment. As is clear from comparison with FIG. 2, in this embodiment, instead of the pressure sensor 36 described above, the EGR valve 18 detects the lift amount LV as the operation amount (opening) of the valve body 18c. Lift sensor 37 is provided. In the EGR valve 18,
The lift amount LV of the valve body 18c correlates with the internal pressure (negative pressure) PH of the housing 18b. Therefore, the EGR valve 18
By monitoring the change in the lift amount LV detected by the lift sensor 37 when the ECU 41 is closed,
Similar to the first embodiment, it is possible to determine the abnormality of the ventilation resistance of the filter 22.

The flowchart of FIG. 8 shows the "EGR control routine" in this embodiment, which is similar to the routine of FIG. Other than steps 300 and 340, steps 110 to 130, 150 and 160 are the same as the processing contents shown in the routine of FIG. As a different point, in step 300, the ECU 41 reads the value of the lift amount LV instead of the internal pressure PH. Further, in step 340, instead of comparing the internal pressure PH with the reference value P1, the ECU 41 compares the lift amount LV with a predetermined reference value L1.

The flowchart of FIG. 9 shows the "abnormality detection routine" in this embodiment, which is similar to the routine of FIG. Steps 200 to 2 other than step 450
40, 260-262, 270-272 are the same as the processing contents shown in the routine of FIG. As a different point, in step 450, the ECU 41 compares the lift amount LV with a predetermined reference value L2 instead of comparing the internal pressure PH with the reference value P2.

The timing charts of FIGS. 7A, 7B, and 7C show the behavior of various parameters of this embodiment, and conform to the chart of FIG. 7B and 7C other than FIG. 7A are almost the same as the contents shown in FIGS. 3B and 3C. As a different point, FIG. 7A shows a change in the lift amount LV instead of showing a change in the internal pressure PH.

Therefore, also in this embodiment, the same operation and effect as those of the first embodiment can be obtained. The present invention can be embodied in another embodiment described below. Also in the following other embodiments, it is possible to obtain the same actions and effects as those of the above-mentioned respective embodiments.

(1) In each of the above embodiments, the EGR valve 18
The abnormality of the filter 22 was determined by monitoring the responsiveness of the EGR valve 18 when the valve was closed from the fully opened state.
On the other hand, the abnormality of the filter 22 may be determined by monitoring the intermediate responsiveness of the EGR valve 18 when the EGR valve 18 is closed from the fully opened state to the predetermined opening degree.

(2) In each of the above embodiments, the present invention is embodied in a diesel engine system, but it may be embodied in a gasoline engine system. (3) In each of the above embodiments, the abnormality of the ventilation resistance of the filter 22 is detected as the abnormality of the ventilation resistance of the atmosphere port 19c of the EVR valve 19. On the other hand, when the air port is communicated with the intake passage, it is possible to detect an abnormality in the air passage resistance of the intake passage as an abnormality in the air passage resistance associated with the air port.

(4) In each of the above embodiments, the vacuum pump 21 is used as the negative pressure supply source. However, the negative pressure supply source is an appropriate portion of the intake passage where negative pressure is generated during engine operation, and the EVR is used. The negative pressure port of the valve may be communicated with that portion.

Further, it will be described below together with the effect that each embodiment of the present invention includes the following various embodiments according to the technical idea described in the claims. (A) In the invention described in claim 1, when the abnormality determining means determines the abnormality of the ventilation resistance, the notifying means is provided for notifying the occurrence of the abnormality.

According to this structure, a person can immediately know the abnormality of the ventilation resistance, and it is possible to deal with the abnormality earlier by receiving the report. (B) In the invention according to claim 1, when the abnormality determining means determines the abnormality of the ventilation resistance, a recording means for recording the occurrence of the abnormality is provided.

According to this structure, it is possible to promptly deal with the abnormality of the ventilation resistance by appropriately reading the record of the recording means.

[0066]

According to the first aspect of the invention, the exhaust gas recirculation system for an internal combustion engine is premised on the negative pressure operating valve having a negative pressure regulating valve for selectively introducing the operating negative pressure and the atmospheric pressure. And Then, the valve closing response state of the negative pressure operated valve is measured, and when the measured valve closing response state becomes worse than the reference valve closing response state, it relates to the port for introducing atmospheric pressure to the negative pressure regulating valve. It is determined that the ventilation resistance is abnormally large.

Therefore, even if the ventilation resistance related to the atmospheric pressure introducing port increases unknowingly, an abnormality in the ventilation resistance is determined without omission based on the operation response of the negative pressure operation valve. Therefore, it is possible to easily and properly detect an abnormality in the ventilation resistance of the port for introducing the atmospheric pressure of the negative pressure adjusting valve.

[Brief description of the drawings]

FIG. 1 is a conceptual configuration diagram showing a configuration of the present invention.

FIG. 2 is a schematic configuration diagram showing an engine system according to a first embodiment.

3 (a), (b), and (c) are timing charts showing the behavior of various parameters.

FIG. 4 is a flowchart showing an “EGR control routine”.

FIG. 5 is a flowchart similarly showing an “abnormality detection routine”.

FIG. 6 is a schematic configuration diagram showing an engine system according to a second embodiment.

7 (a), (b), and (c) are timing charts showing the behavior of various parameters.

FIG. 8 is a flowchart showing an “EGR control routine”.

FIG. 9 is a flowchart showing an “abnormality detection routine”.

FIG. 10 is a schematic configuration diagram showing a conventional EGR valve and EVR valve.

FIG. 11 is a graph showing the relationship between the response time of pressure change at the output port of the conventional EVR valve and the ventilation resistance of the filter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Diesel engine as an internal combustion engine, 6 ... Intake passage, 13 ... Exhaust passage, 16 ... EGR device, 17 ... EGR
Passage, 18 ... EGR valve, 19 ... EVR valve, 19a ... 1st
, 19b ... Negative pressure port as second port, 19c ... Atmosphere port as third port, 21 ... Vacuum pump as negative pressure supply source, 22 ... Filter, 30 ... Warning lamp , 41 ... ECU
(41 constitutes measuring means and abnormality determining means).

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location F02D 45/00 301 F02D 45/00 301F

Claims (1)

[Claims] 1. An exhaust gas recirculation device for recirculating a part of exhaust gas discharged from an internal combustion engine to an exhaust passage to the internal combustion engine and returning the exhaust gas to the internal combustion engine. Recirculation of the exhaust gas is controlled. The negative pressure operating valve that selectively opens and closes based on the negative pressure and the atmospheric pressure that are selectively supplied to the negative pressure operating valve, the first port that communicates with the negative pressure operating valve, and the second port that communicates with the negative pressure supply source. Port and a third port communicating with the atmosphere, and the first and second ports for opening the negative pressure operated valve.
Ports are communicated with each other to introduce a negative pressure to the negative pressure operated valve, and the first and third ports are communicated with each other to close the negative pressure operated valve to introduce atmospheric pressure to the negative pressure operated valve. In the abnormality detection device for an exhaust gas recirculation device including the negative pressure adjusting valve configured as described above, measuring means for measuring a valve closing response state of the negative pressure operating valve, and the measured valve closing response An abnormality determining means for determining that the ventilation resistance related to the third port of the negative pressure regulating valve is abnormally large when the state becomes worse than a predetermined reference valve closing response state. Detector for exhaust gas recirculation system of internal combustion engine.