JPH02130252A - Anomaly judging device for exhaust recirculation device - Google Patents

Abstract

PURPOSE:To speedily judge anomaly with high precision by compulsorily opening a control valve by a prescribed opening degree in idling state and calculating the variation rate of the revolution speed at this time and comparing the rate with a prescribed value and judging anomaly of an exhaust recirculation device on the basis of the result of the comparison. CONSTITUTION:When an idling judging means M5 judges that an internal combustion engine EG is in idling on the basis of the result of the detection by an operation state detecting means M4, the control valve M2 of an exhaust recirculation device (EGR device) M3 is compulsorily opened by a prescribed opening degree by a compulsorily valve opening means M6. The variation rate of the revolution speed of the engine EG in the case when the valve M2 is opened is calculated on the basis of the result of the detection of the detecting means M4, by an operation speed variation rate calculating means M7, and the variation rate is compared with a prescribed value by a comparing means M8, and an anomaly judging means M9 judges the anomaly of the EGR device M3 on the basis of the result. Further, even if the opening degree of the valve M2 which is detected by the means M6 is little, the revolution variation of the engine EG can be detected, and the generation of stall can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides an exhaust gas recirculation (hereinafter referred to as EGR) device that recirculates a part of the exhaust gas of an internal combustion engine to the intake system. The present invention relates to an abnormality determination device for an exhaust gas recirculation device that determines an abnormality in an EGR device in an internal combustion engine.

[Prior Art] Conventionally, some internal combustion engines are equipped with an EGR device that recirculates a portion of exhaust gas to an intake system in order to reduce NOX contained in the exhaust gas. Such an EGR device has a control valve (
An EGR valve (hereinafter referred to as an EGR valve) is provided, and when the internal combustion engine is in a predetermined EGR operating range, the opening degree of the EGR valve is controlled based on the rotational speed and load of the internal combustion engine to determine the EGR amount. ing.

By the way, if the EGR system malfunctions due to malfunction of the EGR valve or blockage of the exhaust gas recirculation path, the N
Ox tends to increase significantly. However, EGR failure
Since it has little effect on driving performance itself, a large amount of NOx may be emitted without the driver noticing an abnormality, polluting the atmosphere.

As a countermeasure to this problem, a device for determining failure of the EGR device has been proposed, for example, as described in Japanese Utility Model Application Publication No. 62-71363. That is, E.G.
A gas temperature sensor or the like is installed in the R pipe, and it is determined from the change in gas temperature that the exhaust gas is being recirculated normally.

However, the above-mentioned conventional example requires a gas temperature sensor, complicates the configuration, and increases costs.
Calculate the deviation of the rotational speed of the internal combustion engine when the GR device is switched from on to off, and if the deviation of the internal combustion engine is less than a predetermined one shift, it is determined that the EGR quantity is abnormal.
It has been proposed in Japanese Patent Application Laid-Open No. 62-51746.

[Problems to be Solved by the Invention] However, in such a conventional device, when a small amount of EGR is recirculated to the intake system when the EGR device is turned on, the deviation in the rotational speed of the internal combustion engine is small; Since it takes time to obtain this, in order to quickly and accurately determine the abnormality, it is necessary to increase the amount of EGR when EGR is turned on. For this reason, if an attempt is made to determine an abnormality in the EGR system during idling, when steady operation is possible, a large amount of EGR will be returned to the intake system during idling, when the engine speed is low, and as a result, the internal combustion A problem occurred that caused the engine to stall and stop.

The present invention has been made in view of the above-mentioned problems, and provides an abnormality determination device for an exhaust gas recirculation system that can quickly and accurately determine an abnormality in an EGR system without causing a stall in the internal combustion engine. is intended to provide.

[Means for solving the problem] In order to achieve the above object, the present invention has adopted the configuration shown below as a means for solving the problem. That is, as illustrated in the basic configuration diagram of FIG. 1, the abnormality determination device for the exhaust gas recirculation device of the present invention includes a control valve in the exhaust gas recirculation path M1 connecting the exhaust system and intake system of the internal combustion engine EG. M2, and an exhaust gas recirculation device M3 that controls the opening degree of the control valve M2 and recirculates a part of the exhaust gas to the intake system when the internal combustion engine EC is under a predetermined operating range. and the exhaust gas recirculation device M3
An abnormality determination device for an exhaust gas recirculation device that detects an abnormality in C1; an operating state detection means M4 for detecting an operating state of the internal combustion engine EC including at least the rotational speed of the internal combustion engine EC; and a detection of the operating state detection means M4. idling determining means M5 for determining whether or not the internal combustion engine EG is in an idling state based on the result; and when the idling determining means M5 determines that the internal combustion engine EG is in an idling state, controlling the exhaust gas recirculation device M3; a forced valve opening means M6 that forcibly opens the valve M2 to a predetermined opening degree; and a forced valve opening means M6 that forcibly opens the valve M2 based on the rotational speed of the internal combustion engine EC, which is one of the detection results of the operating state detection means M4.
a rotational speed fluctuation rate calculating means M7 for calculating the fluctuation rate of the rotational speed when the control valve M2 is opened; Comparison means M for comparing with a predetermined value
8, and abnormality determination means M9 for determining abnormality of the exhaust gas recirculation device M3 based on the comparison result of the comparison means M8.

[Operation] The abnormality determination device for an exhaust gas recirculation device of the present invention configured as described above is configured such that when the internal combustion engine EG is under a predetermined operating range, the exhaust gas recirculation path M3
A part of the exhaust gas is recirculated to the intake system by controlling the opening degree of the control valve M2 disposed in the idling determination means M.
5, when it is determined that the internal combustion engine EG is in the idling state based on the detection result of the operating state detection means M4, the control valve M2 of the exhaust gas recirculation device M3 is opened to a predetermined opening degree by the forced valve opening means M6. Calculating the fluctuation rate of the rotational speed of the internal combustion engine EG when the control valve M2 is forcibly opened by the rotational speed fluctuation rate calculation means M7 based on the detection result of the operating state detection means M4, The comparison means M8 compares the calculated rotational speed fluctuation rate with a predetermined value, and based on the comparison result, the abnormality determination means M9 determines whether there is an abnormality in the exhaust gas recirculation device M3. work.

Therefore, even if the opening degree of the control valve M2 forcibly opened by the forced valve opening means M6 is small and only a small amount of EGR can be obtained, by comparing the fluctuation rate of the rotational speed of the internal combustion engine EG with a predetermined value, , it is possible to reliably detect rotational fluctuations of the internal combustion engine EG based on the EGR amount. Moreover, since a small amount of EGR is sufficient to detect rotational fluctuations,
There is no possibility of stalling of the internal combustion engine EG.

[Embodiments] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a schematic configuration diagram showing an internal combustion engine for a vehicle equipped with an abnormality determination device for an EGR system according to a first embodiment of the present invention, and its peripheral devices.

As shown in the figure, intake air that has passed through an air cleaner 6 flows into an intake pipe 4 of an internal combustion engine 2, and an intake air temperature sensor 8 that detects intake air temperature is attached to the air cleaner 6. In addition, a throttle valve 10 is provided in the intake pipe 4.
is provided, and the amount of intake air to the internal combustion engine 2 is controlled by controlling the opening of the throttle valve 10. The throttle valve 10 is equipped with a throttle position sensor 11 equipped with an idling (hereinafter also referred to as idling) switch that detects its opening degree and detects its fully closed state. Further, a bypass passage 12 is formed to bypass the intake pipe 4 in which the throttle valve 10 is inserted, and an idle speed control valve (hereinafter referred to as 15CV) 14 is inserted in the bypass passage 12. ing. The l5CV14 is a so-called step motor type in which a rotor 14a of a step motor rotates in response to a pulse signal from an electronic control circuit to be described later, and the lift amount of the valve body 14b changes, thereby changing the opening area of the valve. , by controlling the opening degree of l5CVI4, the amount of intake air to the internal combustion engine 2 is controlled independently of the throttle valve 10. Further downstream of the intake pipe 4, a surge tank 16 is formed to suppress pulsation of intake air, and an intake pressure sensor 17 is provided to detect the absolute pressure (intake pressure) within this tank.

On the other hand, in the exhaust pipe 18 of the internal combustion engine 2, there is an air-fuel ratio sensor 20 that detects the air-fuel ratio of the fuel mixture supplied to the internal combustion engine 2 from the opening degree (oxygen in the exhaust gas) and a three-way catalyst for purifying the exhaust gas. A converter 22 is provided. The exhaust pipe 18 is also provided with an EGR device 24 that recirculates the exhaust gas by returning it to the intake pipe 4.

The EGR device 24 has a configuration in which an EGR valve (hereinafter referred to as EGRV) 28 and an EGR cooler 30 are provided in an exhaust gas recirculation path 26 that connects the exhaust pipe 1 and the surge tank upstream of the intake pipe 4. This EGRV2B is a so-called step motor type in which a rotor 28a of a step motor rotates in response to a pulse signal from an electronic control circuit to be described later, and the lift a of the valve body 28b changes, thereby changing the opening area of the valve. By controlling the opening degree of this EGRV 28, the amount of exhaust gas recirculated to the intake pipe 4 is controlled. The EGR cooler 28 lowers the temperature of gas flowing through the exhaust gas recirculation path 26 with a water passage along the exhaust gas recirculation path 26.

The distributor 32 is for distributing the high voltage output from the igniter 34 to the spark plugs 36 of each cylinder in synchronization with the crank angle of the internal combustion engine 2, and the ignition timing of the spark plugs 36 is determined by the high voltage output from the igniter 34. Determined by output timing.

In addition, the internal combustion engine 2 includes:
The above-mentioned intake temperature sensor 8 and throttle position sensor 1
1. In addition to the intake pressure sensor 17 and the air-fuel ratio sensor 20,
Internal combustion engine 2 from the rotation of the rotor of distributor 32
a rotational speed sensor 38 that detects the rotational speed of the rotor; a height determination sensor 40 that outputs a pulse signal once every two revolutions of the crankshaft of the internal combustion engine 2 in accordance with the rotation of the rotor; A water temperature sensor 42 is provided to detect the water temperature, and a vehicle speed sensor 44 is provided near the axle and generates a pulse signal according to the vehicle speed. Further, an unillustrated instrument panel of a vehicle equipped with such an internal combustion engine 2 is provided with an alarm lamp 45 that notifies the driver of an abnormality in the EGR device 24.

Detection signals from each sensor are output to an electronic control circuit 46 configured as a logic operation circuit centered on a microcomputer. Based on these detection signals, the electronic control circuit 46 drives the fuel injection valve 48 to start the internal combustion engine 2.
control the fuel injection amount to the IS, drive the igniter 34 to control the ignition timing, drive the l5CV14 to control the IS
It executes C control, drives the EGRV 2B to execute EGR control, executes EGR abnormality diagnosis processing, and lights up the alarm lamp 45.

Note that, as shown in FIG. 3, the electronic control circuit 46 includes a CPU 50 that executes various arithmetic processing for the control according to a preset control program, and a control program necessary for the CPU 50 to execute the arithmetic processing. R0M52 in which initial data is stored in advance, RAM54 in which various data are temporarily read and written to assist the arithmetic processing executed by the CPU 50, and backup by random to retain various data even after the power is turned off. a backup RAM 55, a clock signal generation circuit 56 that generates a clock signal that determines the control timing necessary for the CPU 50 to execute arithmetic processing, a human powered boat 58 that manually inputs the detection signals from each of the sensors, and l5CV14, EG RV 2 B, and fuel injection valve 4
It is composed of an output port 0 that outputs a drive signal to the igniter 34 and a lighting voltage to the alarm lamp 45.

Next, the main routine representing the basic control of the internal combustion engine executed by the electronic control circuit 46 will be explained using the flowchart in FIG. 4, and then the various processes executed therein will be explained in FIGS. This will be explained in detail using the flowchart shown in FIG.

This main routine starts executing when a key switch (not shown) is turned on. As shown in Figure 4, when the process starts, it first performs initialization such as setting initial values of various data. Processing is performed (step 100).

Subsequently, a value of 1 is set in the EGR abnormality diagnosis process permission flag XEGRDG, which determines whether or not to execute the EGR abnormality diagnosis process to be described later (step 110). Next, the vehicle speed SPD is determined from the detection result of the vehicle speed sensor 44, the idle signal LL is determined from the detection result of the idle switch of the throttle position sensor 11, and the current opening degree (actual opening degree) of the EGRV 28 is determined from the execution result of the R9TEP calculation routine, which will be described later.
A process of reading each R9TEP is executed (step 120).

After executing step 120, the process moves to steps 130 to 160, and various determination processes are executed.

Specifically, if the vehicle speed SPD read in step 120 is
km/h or not (step 130), step 1
Determining whether or not the idle signal LL read in step 20 is Hani 1, that is, whether or not it is in the idle state (step 140);
Determining whether the actual opening degree R9TEP read in step 120 is 0, that is, whether it is fully open (step 150);
A determination (step 160) is made as to whether or not the EGR abnormality diagnosis process permission flag XEGRDG has a value of 1, that is, whether or not the EGR abnormality diagnosis process is permitted.

If all of the determinations in steps 130 to 160 are affirmative, the process moves to step 170.

In step 170, EGR abnormality diagnosis processing is executed.

This EGR abnormality diagnosis process is a process related to the main configuration of the present invention for determining whether or not a failure has occurred in the EGR device 24, and will be explained in detail later, but according to this process,
When it is determined that a failure has occurred in the EGR device 24, the warning lamp 45 is turned on and the EGR abnormality flag XEGR is turned on.
The value 1 is set in F. After executing the EGR abnormality diagnosis process in step 170, step 180 sets the EGR abnormality diagnosis process permission flag XEGRDG to a value of 0.
), the process moves to step 190.

On the other hand, if a negative determination is made in any of steps 130 to 160, the process skips steps 170 and 180 and proceeds to step 190.

The step 190 executes a fuel injection time calculation process to determine the amount of fuel to be injected into the internal combustion engine 2, and then calculates the ignition timing to determine the ignition timing of the spark plug 36. '
step 192) to execute the il calculation process, step 194) to execute the EGRV control amount calculation process to determine the control amount of EGRV2B for EGR control, and step 194) to execute the IS calculation process.
I SCV control amount calculation processing is executed to determine the control amount of I SCV 14 for C control (step 19
6). Note that the fuel injection time calculation process, ignition timing calculation process, and EGRV control amount calculation process will be described in detail later.

Next, it is determined whether or not the operation of the internal combustion engine 2 is to be continued (step 198), and if it is determined to be continued, the process returns to step 120.

On the other hand, when the operation is stopped, the process ends.

As shown in FIG. 5, which will be explained next, the EGR abnormality diagnosis process executed in step 170 is performed based on the flowchart in FIG. A process is executed to set the degree TSTEP to a predetermined value α that is an EGRV opening degree that causes slight fluctuations in rotation of the internal combustion engine in an idling state (step 200). Next, a CDLNE calculation process is executed to calculate a fluctuation rate counter CDLNE representing the rotational speed fluctuation rate α of the internal combustion engine (step 210).
.

In detail, in the CDLNE calculation process, as shown in FIG. 6, first, the fluctuation rate counter CDLNE and the time counter C3M5 are each set to the value 0 (step 211).
Then, the rotation speed NE is read from the detection result of the rotation speed sensor 38 (step 212). Next, the rotational speed deviation DLNE is calculated by subtracting the previous rotational speed NEO stored in step 214, which will be described later, when this routine was last processed from the read rotational speed NE.
Step 213). Subsequently, the rotational speed NE read by the stem 212 is stored as the previous rotational speed NEO (step 214). After that, the rotation speed side difference DL
Step 215) Determine whether NE is greater than or equal to a predetermined value B.
, if it is determined that the rotational speed is greater than or equal to the predetermined value B, it is assumed that there has been a rapid fluctuation in the rotational speed, and the fluctuation rate counter CDLNE is incremented by the value 1 (step 216). - On the other hand, if it is determined in step 215 that it is smaller than the predetermined value B, the process in step 216 is skipped. Subsequently, the time counter C3M5 is incremented by the value 1 (step 217), and it is determined whether or not the time counter C3M5 has become equal to or greater than the value β indicating that 3 seconds have passed (step 218). Here, if it is determined that C3M5 is smaller than the value β, it is determined that 3 seconds have not yet elapsed, and the process returns to step 212, and the processes of steps 212 to 218 are repeated. On the other hand, if it is determined in step 218 that C3M5 is greater than or equal to the value β, it is assumed that 3 seconds or more have elapsed, and the process exits to rRETURNJ and proceeds to step 220 in FIG.

That is, according to this CDLNE arithmetic processing, by counting how many times there is a sudden change in the rotational speed such that the deviation DLNE of the rotational speed within a predetermined time is equal to or greater than the predetermined value B in 3 seconds, The rapid fluctuation rate is calculated as a fluctuation rate counter CDLNE.

Returning to FIG. 5, after executing the CDLNE calculation process, the process moves to step 220, and the calculated fluctuation rate counter C
It is determined whether DLNE is less than or equal to a predetermined value A. Here, if it is determined that the value is below the predetermined value A, it is assumed that there is something wrong with the EGR device 24, and an EGR abnormality display is executed in which the warning lamp 45 is turned on (step 230). Set the EGR abnormality flag XEGRF to the value 1 (step 24
0).

After that, this routine is temporarily ended. On the other hand, step 2
If it is determined in step 10 that CDLNE is greater than the predetermined value A, steps 230 and 240 are skipped and this routine is temporarily ended.

The fuel injection time calculation process executed in step 190 is performed in the seventh step.
Based on the flowchart in the figure, as shown in FIG.
, the throttle opening TA, intake pipe pressure PM, rotation speed NE, cooling water temperature THW, etc. are read from the detection results of the rotation speed sensor 38, water temperature sensor 42, etc. (step 300), and the rotation speed NE and intake pipe pressure PM are read. A process is executed to calculate the basic fuel injection time TP from (step 310). The basic injection time TP is defined by a two-dimensional map of the rotational speed NE and the intake pipe pressure PM, and the basic injection time TP is determined based on such a basic injection time map ζ stored in the ROM 52 in advance. is calculated. Next, in order to determine whether the EGR device 24 is out of order, it is determined whether the EGR abnormality flag XEGRF obtained in the EGR abnormality diagnosis process described above is 1 (step 320). . Here, if it is determined that the EGR device 24 is not in one shift, that is, the EGR device 24 is not out of order, the rotational speed N read in step 300
EGR fuel correction coefficient FEGR from E and intake pipe pressure PM
Step 330), the basic fuel injection time TP is multiplied by the EGR fuel correction coefficient FEGR to calculate the basic injection time TP that takes into account the influence of EGR (Step 34).
0). Note that the EGR fuel correction coefficient FEGR is defined by a two-dimensional map of the rotational speed NE and the intake pipe pressure PM, and is based on such an EGR fuel correction coefficient stored in the ROM 52 in advance.
FEGR is calculated based on the fuel correction coefficient map. On the other hand, if it is determined in step 320 that the EGR device 24 is out of order, the processes in steps 330 and 340 are skipped.

After that, the throttle opening degree T read in step 300
A. Calculate various fuel correction coefficients f based on cooling water temperature THW, etc. Step 350), Step 310 or 3
Multiply the basic fuel injection time TP calculated in step 40 by the various fuel correction coefficients f to calculate the fuel injection time TAU (
step 360). After executing step 360, the processing of this routine is temporarily terminated.

The ignition time calculation process executed in step 192 is based on the flowchart of FIG. 8, and as shown in FIG. The intake pipe pressure PM, rotational speed NE, cooling water temperature THW, etc. are read from the detection results of the water temperature sensor 42 and the like (step 400);
A process for calculating the basic fuel ignition timing ABASE from the rotational speed NE and intake pipe pressure PM is executed (step 410). The basic ignition timing ABASE is defined by a two-dimensional map of rotational speed NE and intake pipe pressure PM.
Based on such a basic ignition time map stored in the ROM 52 in advance, the basic ignition timing ABASE is calculated. Next, in order to determine whether or not the EGR device 24 is out of order, the EGR abnormality flag XEGRF described above is
It is determined whether or not the value is 1 (step 420). Here, if it is determined that (not 11, that is, the EGR device 24 is not malfunctioning), calculate the EGR ignition timing correction coefficient AEGR from the rotational speed NE and intake pipe pressure PM read in step 400. Step 430), EGR ignition timing correction coefficient AEGR is added to the basic ignition timing ABASE.
Basic ignition timing AB which takes into account the influence of EGR by adding
ASE is calculated (step 440). The EGR ignition time correction coefficient AEGR is determined by the rotational speed NE and the intake pipe pressure PM, which is stored in advance in the ROM 52.
Calculated based on the dimensional map.

On the other hand, if it is determined in step 420 that XEGRF is the value 1, that is, the EGR device 24 is out of order, steps 430 and 440 are skipped.

Thereafter, various ignition timing correction coefficients AAD are calculated based on the coolant temperature THW etc. read in step 400. In step 450), the basic ignition timing ABASE calculated in step 410 or 440 is multiplied by the various ignition timing correction coefficients AAD. , calculate the ignition time AOP (step 460).

After executing step 460, the processing of this routine is temporarily terminated.

As shown in FIG. 9, which will be explained next, the EGRV control amount calculation process executed by the step unit 194 is performed based on the flowchart in FIG. In order to determine whether or not there is a failure, the EG obtained in the EGR abnormality diagnosis process described above
It is determined whether the R abnormality flag XEGRF has a value of 1 (step 500). Here, it is not 1 shift 1, that is, E
If it is determined that the GR device 24 is not malfunctioning,
Throttle position sensor 11, intake pressure sensor 17,
From the detection results of the rotational speed sensor 38, water temperature sensor 42, etc., a process is performed to read the throttle opening TA, intake pipe pressure PM, rotational speed NE, cooling water temperature TF (W, etc.) (step 510).Next, By determining whether the read values of throttle opening TA and cooling water temperature T)IW satisfy predetermined conditions, it is possible to determine whether the operating state of the internal combustion engine is in the exhaust gas recirculation region (EGR region). It is determined whether or not (step 520). Here, if it is determined that the area is in the EGR area, the following process is executed. First, a process is performed to calculate the commanded opening degree TSTEP of the EGR valve 28 from the rotational speed NE and intake pipe pressure PM read in step 510 (step 5
30). The command opening degree TSTEP is defined by a two-dimensional map of the rotational speed NE and the intake pipe pressure PM, and is determined in advance by R.
It is calculated based on the indicated opening degree map as shown in FIG. 11 stored in the OM 52. Note that in FIG. 11, the values between each cell are determined by interpolation calculation. Next, from the calculated instruction opening degree TSTEP, R5T, which will be described later, is determined.
Actual opening degree R of EGRV2B calculated by the EP calculation routine
5TEP to calculate the opening difference VSTEP (step 540), and the calculated opening difference VSTEP is calculated.
Calculate the control amount of EGRV28 based on STEP (
step 550).

After executing step 550, the processing of this routine is temporarily ended. On the other hand, if it is determined in step 520 that it is not the EGR region, steps 530 to 550 are skipped and the processing of this routine is ended without executing the opening degree control of EGRV 2B. Also, in step 500,
Steps 510 to 5 are also performed when EGRF has a value of 1, that is, it is determined that the EGRiW device 24 is malfunctioning.
50 is skipped, and the processing of this routine is ended without executing the opening degree control of the EGRV 28.

Next, R3 calculates the actual opening degree R9TEP of EGRV2B.
The TEP calculation routine will be explained.

This routine runs for a predetermined period of time, 8m5ec in this routine.
This is a process that is executed by an interrupt every time. When the process starts, first, the command opening degree T calculated in the EGR control routine is
STEP is the actual opening R5T calculated in this routine last time.
It is determined whether it is equal to EP (step 600). Here, if it is determined that the two are not equal, then R9
It is determined whether TEP is greater than TSTEP (step 610). Here, if it is determined that R9TEP>TSTEP, the actual opening degree R5TEP is incremented by the value 1 (step 620), and if R9TEP≦TSTEP
When it is determined that the actual opening degree R9TEP is decremented by the value 1 (step 630). After executing step 620 or step 630, the processing of this routine ends.

On the other hand, if it is determined in step 600 that the instructed opening degree TSTEP and the actual opening degree R9TEP are equal, steps 610 to 630 are skipped, and the processing of this routine ends.

According to such R9TEP calculation routine, EGRV2
In order to control the opening degree of B, the commanded opening degree T is set in the EGR control routine.
When STEP is output, the actual opening R3TEP is updated by one step every interrupt time of this routine, that is, every 8 m5ec. This configuration was made because the operation delay time from when the EGRV28 receives an opening instruction until it actually reaches that opening is 8 m5ec for one step, and for this reason, the R9TFPW output routine is By executing this, the current actual opening degree R5TEP of the EGRV 28 is calculated.

As described in detail above, the abnormality determination device for the EGR device of this embodiment is configured such that when the vehicle speed SPD is Okm/h and the idle signal L
L has a value of 1, EGRV28 (7) actual opening R9TEP has a value of 0
In this case, if the opening degree of the EGRV 2B is forcibly opened to a predetermined value α, and the fluctuation rate CDLNE of the rotational speed NE at that time becomes less than the predetermined value A, the EGR device 24 is considered to be abnormal and the first notification lamp 45 is activated. is configured to light up.

Therefore, even if the forced opening degree α of EGRV2B is large enough to obtain only an amount of EGR that causes slight rotational fluctuations of the internal combustion engine, the fluctuation rate CD of the rotational speed NE
Since EGR abnormality is determined based on LNE, the rotational fluctuation can be reliably detected. the result,
EGR without causing a stall in the internal combustion engine 2.
Abnormalities in the device 24 can be determined quickly and reliably.

Further, in this embodiment, when determining the amount of fuel injection to the internal combustion engine 2 when it is determined that the EGR device 24 is abnormal,
Since the EGR device 24 is configured to stop correction of the fuel injection amount based on the GR fuel correction coefficient FEGR,
Even in the event of an abnormality, the amount of fuel injection can be optimized, and deterioration of the air-fuel ratio can be prevented.

Furthermore, when it is determined that the EGR device 24 is abnormal, when driving the igniter 34 to determine the ignition timing, the EGR
Since the ignition timing correction based on the R ignition time correction coefficient AEGR is configured to be stopped, the EGR device 24
Even in the event of an abnormality, the ignition timing can be optimized, and deterioration of combustion in the internal combustion engine 2 can be prevented.

In addition, when it is determined that the EGR device 24 is abnormal, the EGR
Opening control of the RV 2B is stopped to prevent exhaust gas from being recirculated by the abnormal EGR device 24.

By the way, in the above embodiment, according to the CDLNE calculation process shown in FIG. 6, the process is repeated for 3 seconds, but instead of this, when the internal combustion engine 2 leaves the idle state, stops the EGR abnormality diagnosis process even if the CDLNE calculation process is in progress, and switches the process to the fourth one.
It may be configured to proceed to step 190 in the figure.
By doing so, it is possible to improve safety when the idle state is interrupted in a short period of time.

A second embodiment of the invention will now be described.

This embodiment has the same hardware configuration as the first embodiment, but has a different configuration in the processing executed by the electronic control circuit 46 compared to the first embodiment. Hereinafter, such processing will be explained in detail using FIGS. 12 to 15.

FIG. 12 is a flowchart showing the main routine representing the basic control of the internal combustion engine 2.
793, 794 are steps 100, 110° 130 to 160, 194, 19 in FIG. 4 of the first embodiment.
The processing is the same as that of 0.192. Therefore, this routine will be explained below while briefly explaining these same processes.

As shown in FIG. 12, when the process is started, first the initialization process is executed (step 700), then the EGR
The abnormality diagnosis processing permission flag XEGRDG is set to the value 1 (step 71O). Next, similarly to step 120, the vehicle speed SPD, idle signal LL, and actual opening degree R3TEP of EGRV2B are read, and the water temperature sensor 4 is read.
A process of reading the cooling water temperature THW from the detection result of step 2 is executed (step 720). Next, the vehicle speed SPD is OK.
/h or not (step 730), idle signal LL (-1 or not (step 740)), EG
It is determined whether the actual opening degree R3TEP of RV2B is 0 or not (step 750), and the EGR abnormality diagnosis processing permission flag XEG is set.
It is determined whether RDG has a value of 1 (step 760). Further, it is determined whether the coolant temperature TF (W) read in step 720 is 80° C. or higher, and it is determined whether the internal combustion engine 2 has been warmed up (step 770), and the idle signal LL is It is determined whether one second has passed since the first shift, that is, the idle state (step 780).If all the determinations in steps 730 to 780 are affirmative, as will be described later. EGR abnormality diagnosis processing is executed (step 790).
If a negative determination is made in any of steps 30 to 780, a variable CDLNE and an EGR abnormality diagnosis execution flag XEGRDE, which will be described later, are set to 0 (step 791), and EGRV control amount calculation processing is executed (step 792).

After executing step 790 or step 792, the process moves to step 793, where a fuel injection time calculation process is executed, and then an ignition timing calculation process is executed.
4) Furthermore, the l5CV control amount calculation process, which will be explained in detail later, is executed (step 795). Next, the operation of internal combustion engine 2 is 1Iil! It is then determined whether or not to continue (step 796); if it is determined to be continued, the process returns to step 720. On the other hand, when the operation is stopped, the process ends.

The EGR abnormality diagnosis process executed in step 790 is
Variation rate DLNEN of rotation speed NE when RV is fully closed and EG
The difference between the fluctuation rate of rotational speed NE when RV2B is forcibly opened to the first predetermined opening is equal to or less than a predetermined value, and the fluctuation rate DLNEN when fully opened and EGRV28 are set to the second predetermined opening. This is to diagnose that there is something wrong with the EGR device 24 when the difference between the fluctuation rate of the rotational speed NE and the rate of change when the engine is forcibly opened is less than a predetermined value, and the flowchart shown in FIG. It is executed based on.

As shown in FIG. 13, when the process moves to this routine, first the EGR error diagnosis process is executed.
The R abnormality diagnosis execution flag XEGRDE is set to country 1 (step 800), and then it is determined whether the variable CDLNE is 1 shift 0 or not (step 810). The variable CDLNE is
This is one variable calculated in the DLNEN calculation routine shown in FIG. 14, and the DLNEN calculation routine will be explained below. Note that this routine is executed every predetermined crank angle of the internal combustion engine 2.

As shown in FIG. 14, when the process starts, first
It is determined whether the GR abnormality diagnosis execution flag XEGRDE is 1 (step 820), and then it is determined whether the indicated opening degree TSTBP of EGRV2B is equal to its actual opening degree R9TEP (step 822). In addition, the actual opening R9TE
P is calculated by the R9TEP calculation routine shown in FIG. 10 of the first embodiment. If affirmative determinations are made in steps 820 and 822, the process moves to step 824, where the rotation speed difference obtained by subtracting the rotation speed NEO when this routine was executed last time from the current rotation speed NE is calculated using a variable 5DLN.
Execute the process of integrating as E.

Next, an integration counter D indicating the number of times the integration process has been executed
Increment LNEC by value 1.82
6), it is determined whether the DLNEC has reached a predetermined value C (step 828). When the predetermined 1 direct C is reached, the 5DLNE accumulated by the step 824 is then set to the predetermined value C.
(Step 8
30). Subsequently, a value of 1 is set to the flag XDLNF: indicating that the calculation of this DLNEN has been completed (step 832). Next, it is determined whether or not the counter CDLNE, which counts the number of times DLNEN has been calculated, is greater than the value 1 (Step 834). The variable DLNEA is set as the fluctuation rate of (step 836).

On the other hand, if CDLNE has a value of 1, step 83
Skip step 6. Thereafter, the counter CDLNE is incremented by the value 1 (step 83), and the processing of this routine is temporarily terminated.

On the other hand, if a negative determination is made at step 820 or 822, the integration counter DLNEC and the rotation speed difference 5DL
Clear each NE to zero (step 844), and further clear the flag XDLNE to zero (step 842).
), then the processing of this routine is temporarily terminated.

If a negative determination is made in step 828, the process moves to step 842, where XDLNE is cleared to zero, and the process of this routine is temporarily terminated.

That is, according to this DLNEN calculation routine, the rotational speed difference for a predetermined time is integrated a predetermined number of times C, and the integrated value 5D
By dividing LNE by a predetermined number of times C, the average value DLNEN of the rotational speed difference is calculated as the fluctuation rate of the rotational speed NE. Note that when the counter CDLNE is larger than the value 1, the fluctuation rate of the rotational speed NE is DLNEN
Instead, it is output as DLNEA.

Returning to FIG. 13, if it is determined at step 810 that the counter CDLNE described above has a value of 0, the process proceeds to rRET.
URN" and temporarily end this routine. On the other hand, if it is determined in step 810 that CDLNE does not have a value of zero, the following processing is performed.

First, it is determined whether or not CDLNE is (shift 1) (step 85o), and when it is determined that CDLNE is (shift 1), the rotational speed fluctuation rate DLNEN calculated by the above-mentioned DLNEN calculation routine is read (step 85o). 860), then the predetermined value α and the EGRV opening correction slope 5TEPC (described later).
In the period state, the value 0 is set. ) to calculate the indicated opening degree TSTEP of EGRV28, and
An instruction is given to forcibly open V28 by a first predetermined opening degree (step 870). On the other hand, if a negative determination is made in step 850, steps 860 and 870 are skipped.

In the following step 880, it is determined whether or not CDLNE has a value of 2. If it is determined that CDLNE is 1 shift 2, the process proceeds to step 8.
Proceed to 90. In step 890, it is determined whether a flag XDLNE indicating that the calculation of DLNEN has been completed has a value of 1. Here, if the value is 1, that is, it is determined that the process has been completed, the rotational speed fluctuation rate DLNEA calculated by the above-mentioned DLNEN calculation routine is read (step 900), and then from that DLNEA, step 860 is performed.
It is determined whether the value obtained by subtracting the DLNEN read in is less than or equal to a predetermined value (step 910). Here, if it is determined that the opening degree T of EGRV2B is below the predetermined value,
A predetermined value γ is added to STEP to issue an instruction to forcibly open the EGRV2B by a second predetermined opening degree (step 92
0). Note that if it is determined in step 880 that CDLNE is not the value 2, the processes in steps 890 to 920 are skipped.

In the following step 930, it is determined whether or not CDLNE has a value of 3. If it is determined that the value is 3, the process proceeds to step 9.
Proceed to 40. In step 940, it is determined whether a flag XDLNE indicating that the calculation of DLNEN has been completed has a value of 1. Here, if it is determined that the first test has been completed, the rotational speed fluctuation rate DLNEA calculated by the above-mentioned DLNEN calculation routine is read (step 950), and then from the DLNEA in step 95
It is determined whether the value obtained by subtracting the DLNEN read at 0 is less than or equal to a predetermined value (step 960). Here, if it is determined that the value is below the predetermined value, it is assumed that the EGRi device 2 is abnormal, and an EGR abnormality display is executed in which the warning lamp 45 is lit (step 970), and the EGR abnormality flag XEGRF is immediately set. Set to 1 (step 980)
. Meanwhile, in step 960, DLNEA-DLNEN>
If it is determined that D, the process proceeds to steps 970 and 980.
is skipped and the process moves to step 990, where the EGRV interval compensation degree 5 TEPC is updated by adding the predetermined (direct γ), and the 5 TEPC is stored in the backup RAM 55 (step 990), and the EGR abnormality flag XEGR is
Clear F to zero (step 1000). If it is determined in step 910 that DLNEA-DLNEN>D, the process moves to step 1000 without updating 5TEPC. Note that the EGRV opening correction value 5T stored in the backup RAM 55 in step 990
EPC is added when setting the first forced opening degree during the next abnormality diagnosis.

After executing step 990 or step 1000, the process moves to step 1010, where the EGR abnormality diagnosis process permission flag XEGRDG is cleared to zero, and the process of this routine is temporarily ended.

Note that if it is determined in step 890 or step 940 that the flag end once.

The SCV control amount calculation process executed in step 795 will be explained next using the flowchart of FIG. 15. As shown in the same figure, when the process moves to this routine, first,
A process is executed to calculate various control terms other than the rotational speed feedback control term, such as a water temperature dependent term, which determines the control amount of the l5CV14 (step 1100). Subsequently, it is set in step 800 (FIG. 13) and step 791 (
EGR abnormality diagnosis execution flag X cleared in Figure 12)
It is determined whether EGRDE has a value of 1 (step 1110). Here, (if it is determined that the engine is not in direct 1, that is, the EGR abnormality diagnosis process is not being executed), the target rotation speed of the internal combustion engine 2 is determined, and the actual rotation speed detected by the throttle position sensor 11 is determined. A well-known rotational speed feedback control process for feedback control to the target rotational speed is executed (step 1120), and the processing of this routine is temporarily terminated. On the other hand, if it is determined in step 1110 that XEGRDE is 1, that is, the EGR abnormality diagnosis process is being executed, step 120
Skip the process and temporarily end the process of this routine.

As described in detail above, the abnormality determination device for the EGR device of this embodiment is configured such that when the vehicle speed SPD is Okm/h and the idle signal L
When L has a value of 1, the actual opening degree R9TEP of EGRV2B has a value of 0, the cooling water temperature THW is 80°C, and more than 1 second has passed since the idle state has been reached (Step 730 to 780), E
C; Calculate the fluctuation rate DLNEN of the rotational speed NE when the RV is fully closed, then forcefully open the EGRV2B to the first predetermined opening (step 870), and calculate the fluctuation rate DLNEA of the rotational speed NE at that time and the above Compare the fluctuation rate DLNEN (step 910), and if the difference between both fluctuation rates is less than a predetermined value, roughly forcefully open EGRV2B to a second predetermined opening degree (step 920); Compare the fluctuation rate DLNEA and the fluctuation rate DLNEN of the rotational speed NE (step 960), and if the difference between the two fluctuation rates is less than a predetermined value, it is determined that the EGR device 24 is abnormal, and the warning lamp 4 is turned on.
5 is turned on (step 970).

Therefore, the first forced opening degree and the second forced opening degree of EGRV2B
Even if the forced opening degree of the engine is so large that only an amount of EGR can be obtained that causes slight fluctuations in rotation of the internal combustion engine,
Since the EGR abnormality is determined based on the fluctuation rate DLNEA of the rotational speed NE, the rotational fluctuation can be reliably detected and the stall of the internal combustion engine 2 can be prevented as in the first embodiment. Abnormalities in the EGR 14 and 24 can be determined quickly and reliably without any trouble. In particular, in this embodiment, since the fluctuation rate DLNEA of the rotational speed when EG RV 2 B is forcibly checked is compared with the fluctuation rate DLNEN of the rotational speed NE when EGRV 28 is fully closed,
The abnormality diagnosis can be performed without being affected by the operating state before the EGR abnormality diagnosis, and highly accurate diagnostic results can be obtained.

Furthermore, the comparison between g-movement DLNEA, the rotational speed when EGRV20 is forcibly opened, and the rotational speed fluctuation rate DLNEN when EGRV2B (7) is fully closed is performed twice at different valve opening degrees. Furthermore, even if an opening degree error occurs in the EGRV2B due to manufacturing variations and changes over time, abnormality diagnosis can be performed with higher accuracy, eliminating the possibility of misdiagnosis.

In addition, in this embodiment, the comparison result between DLNEA and DLNEN (referred to as the first comparison result) obtained by opening the EGRV 28 to the first predetermined opening degree indicates that the EGR device 24 may be abnormal. (DLNEA-D
A similar comparison result (second comparison result) when the EGRV 2B was opened to the second predetermined opening degree indicates that the EGR device 24 is not abnormal (DLNEA -DLNEN>0), the increased opening degree β when setting the second predetermined opening degree is E G
It is configured to store the RV open im positive faS T E P C addition L/T and sono 5 TEPC in the backup RAM 55, and use the 5 TEPC in the next abnormality diagnosis. For this reason, if the opening degree of EGRV2B changes due to changes over time, etc., and even if it is instructed to open to a predetermined opening degree, only a small amount of EGR will be obtained, and the EGR24 will be misdiagnosed as abnormal. However, in the next abnormality diagnosis, the predetermined opening degree can be increased by a predetermined value β, and the abnormality diagnosis can be performed with high accuracy.

Further, in this embodiment, during execution of EGR abnormality diagnosis processing,
Since the configuration is such that execution of the rotation speed feedback control process in the l5CV control amount calculation process is stopped, the engine rotation speed is not stabilized based on ISC control during the EGR abnormality diagnosis process, and the diagnosis It is possible to prevent interference caused by ISC control during processing.

Although one embodiment of the present invention has been described in detail above, the present invention includes
It goes without saying that the present invention is not equally limited to these embodiments, and can be implemented in various forms without departing from the gist of the present invention.

As detailed above, the abnormality determination device for the exhaust gas recirculation system of the present invention can quickly and accurately determine abnormalities in the EGRib position without causing a stall in the internal combustion engine. can do.

[Brief explanation of the drawing]

FIG. 1 is a basic configuration diagram showing the basic configuration of an abnormality determination device for an exhaust gas recirculation device according to the present invention, and FIG. A schematic configuration diagram showing the internal combustion engine and its peripheral devices, FIG. 3 is a block diagram for explaining the configuration of the electronic control circuit of the embodiment, and FIG. 4 is a flowchart of the main routine executed by the electronic control circuit. , Fig. 5 to Fig. 10 are flowcharts showing various processes executed in the main routine, and Fig. 11 shows the indicated opening degree TST of RGRV.
FIG. 12 is a flowchart of the main routine in the second embodiment, and FIGS. 13 to 15 are flowcharts showing various processes executed in the main routine. EC...Internal combustion engine Ml...Exhaust gas recirculation path M2...Control valve M3...Exhaust gas recirculation device M4...Operating state detection means M5...Idling determination means M6...Forced valve opening Means Ml...Rotational speed fluctuation rate calculation means M8...Comparison means M9...Abnormality determination means 2
...Internal combustion engine 4...Intake pipe 11...
Throttle position sensor 17...Intake pressure sensor
18...Exhaust pipe 24...EGR device 2
6...Exhaust gas recirculation path 28...EGRV 3
B...Rotation speed sensor 45...Warning lamp
４６・・・Electronic control circuit agent Patent attorney established
Tsutomu (2 idiots) Fig. 1 Fig. 6 Fig. Fig. 8 Fig. Fig. 11 Indicated opening TSTEP No. Sensitive rotation speed NE (r, pm) Fig. Fig. fig.

Claims (1)

[Claims] A control valve is disposed in an exhaust gas recirculation path that connects an exhaust system and an intake system of an internal combustion engine, and the opening degree of the control valve is controlled when the internal combustion engine is within a predetermined operating range. An abnormality determination device for an exhaust gas recirculation device, which is installed in an internal combustion engine having an exhaust gas recirculation device that recirculates a part of the exhaust gas to an intake system, and detects an abnormality in the exhaust gas recirculation device, the device comprising: an operating state detecting means for detecting an operating state of the internal combustion engine including at least a rotational speed; an idling determining means for determining whether the internal combustion engine is in an idling state based on a detection result of the operating state detecting means; a forced valve opening means for forcibly opening a control valve of the exhaust gas recirculation device to a predetermined opening degree when the idling state is determined to be in the idling state by the idling state determining means; and one of the detection results of the operating state detecting means. a rotational speed fluctuation rate calculation means for calculating a fluctuation rate of the rotational speed when the control valve is opened by the forced valve opening means, based on the rotational speed of the internal combustion engine, and the rotational speed fluctuation rate calculation means; and a comparison means for comparing the fluctuation rate of the rotational speed calculated by a predetermined value with a predetermined value, and an abnormality determination means for determining an abnormality in the exhaust gas recirculation device based on the comparison result of the comparison means. Abnormality determination device for exhaust gas recirculation equipment.