JPH09152902A - Control device for internal combustion engine - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To frequently determine whether abnormality or normal is present in a control device which determines abnormality of a sensor or the like and determines whether to restore normality and switches engine control from normal control to fail-safe control or vice versa. To prevent the control from becoming unstable. SOLUTION: The number of pulse signals from the detection of a toothless portion 4 to the next detection of an abnormality of an NE sensor that detects a protrusion 3 of an NE pulser 2 provided on a crankshaft 1 and generates a pulse signal is equal to the number of protrusions 3. When it does not match the number of
If fail-safe control is performed and the cylinder can be discriminated based on the pulse signal from the G sensor provided on the camshaft 5 at the time of detecting the toothless portion 4, it is determined that the NE sensor returns to the normal state.
In the control device that performs normal control, the NE sensor
When the abnormality is frequently switched, the normal recovery is determined only when the abnormality determination is not established. As a result, frequent switching between normal and abnormal can be prevented and stable control can be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention performs predetermined fail-safe control when an abnormality in a control device such as a sensor or actuator used for engine control is judged, and returns engine control to a normal control when it is judged that the control device returns to normal. The present invention relates to a control device for an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, in a control device for controlling an internal combustion engine, such as fuel injection control and ignition timing control,
If an abnormality occurs in a control device such as a sensor or an actuator used for control, the internal combustion engine cannot be normally controlled, and in some cases safety cannot be maintained.
When these control devices are judged to be normal or abnormal, and when they are judged to be abnormal, the use of those control devices is prohibited and other control devices are used instead, or engine control is performed according to a preset control procedure. Performs fail-safe control.

In an apparatus that executes such fail-safe control, the control device may return to a normal state after an abnormality determination. Therefore, whether the control device has returned to the normal state by monitoring the operating state of the control device or the like. If it is determined whether or not the control device returns to normal, the fail-safe control is released, and the engine control is quickly returned to normal control.

[0004]

SUMMARY OF THE INVENTION However, in a control device that makes a determination as to whether a control device has an abnormality and a return to normal as described above, and performs switching from normal control to fail-safe control and switching from fail-safe control to normal control. ,
The determination result of normality / abnormality may change irregularly and frequently, such as normal → abnormality → normal.

In this case, the engine control is also frequently switched from the normal control to the fail-safe control to the normal control, so that the engine control cannot be stably executed and the operating state of the internal combustion engine is unstable. In some cases, fail-safe control may be incomplete and safety may not be sufficiently secured.

Naturally, such a problem occurs when the control device itself actually repeats normal operation / abnormal operation, but in particular, in order to ensure the responsiveness and reliability of control, the abnormality determination is performed. This tends to occur when different conditions are set for the condition and the condition for determining whether to return to normal.

For example, conventionally, a gear-shaped rotation sensor provided on a crankshaft of an internal combustion engine is provided with a missing tooth or an extra tooth, and the position thereof is detected to detect a predetermined rotation angle position of the crankshaft. 2. Description of the Related Art There is known a device that determines a cylinder that controls fuel injection or the like from a detection position.
In this type of device, if the abnormality determination condition for determining the abnormality of the rotation sensor and the normal recovery condition for determining the normal recovery are the same (that is, whether the sensor is abnormal or normal depending on whether the abnormality determination condition is satisfied or not). If you decide),
When the abnormality of the rotation sensor is erroneously determined due to noise or the like, the fail-safe control is executed even though the rotation sensor is operating normally, or when the internal combustion engine is started, the abnormality determination condition of the rotation sensor is satisfied. It may take some time to check whether or not the internal combustion engine cannot be started quickly because the determination of the cylinder that performs fuel injection or ignition is delayed. As a condition, a judgment condition for making an abnormality judgment of the rotation sensor depending on whether or not the detection signal output per rotation of the internal combustion engine from the rotation sensor is normal is set. Based on whether or not the cylinder determination has been successful, the determination condition for determining the normal return is set. It has been performed to set different determination condition. However, if different judgment conditions are set for the abnormality judgment condition and the normal recovery condition in this way, due to the difference between the abnormality judgment condition and the normal recovery condition, the abnormality of the control device is judged at the time of the abnormality judgment, and the control device is judged at the time of the normal recovery judgment. In some cases, the normality is determined, and the determination result of the normality / abnormality is frequently switched, and the above problem is likely to occur.

The present invention has been made in view of these problems, and by performing the abnormality determination and the normal recovery determination of the control device as described above, the engine control is changed from the normal control to the fail-safe control or vice versa. In the switching device,
The purpose is to prevent control from becoming unstable due to frequent switching between abnormal and normal judgments.

[0009]

In order to achieve such an object, in the control device for an internal combustion engine according to claim 1, the abnormality determining means controls the engine based on a preset abnormality determining condition. When an abnormal operation of the control device is determined, a predetermined fail-safe control that does not use the control device is executed, and the normal recovery determination means restores the abnormal operation of the control device to the normal operation based on a preset normal recovery condition. Is detected, the fail-safe control is canceled and the engine control is returned to the normal control using the control device. Then, when the abnormality determination by the abnormality determination means and the normal recovery determination by the normal recovery determination means are alternately repeated at a predetermined frequency, the recovery condition change means causes the normal recovery determination means to determine the normal recovery condition of the control device. To the direction in which it is difficult to return to normal.

Therefore, according to the present invention, when the abnormality determination by the abnormality determination means and the normal recovery determination by the normal recovery determination means are alternately repeated at a predetermined frequency, the normal recovery determination means restores the normal condition of the control device. Becomes difficult to judge,
It is possible to prevent frequent switching of the normal / abnormal determination result of the control device and stabilize the engine control. Further, in particular, in the present invention, since the condition for returning to normal is switched to the direction in which it is difficult to return to normal, when the abnormality determination and the determination of normal return are alternately repeated, the determination result of normality / abnormality of the control device is Since it is stable on the side of ", and fail-safe control is continuously and stably executed, sufficient safety can be ensured.

Next, in a control device for an internal combustion engine according to a second aspect, a first rotation sensor for detecting a rotation state of a crankshaft of a multi-cylinder four-cycle internal combustion engine and a rotation state of a camshaft of the internal combustion engine. And a second rotation sensor for detecting that the first rotation detection signal corresponding to the first reference position detected portion is input from the first rotation sensor by the cylinder discriminating means. The reference position of the specific cylinder is determined from the input pattern of the detection signal from the rotation sensor.

That is, since the first reference position detected portion is provided at a specific position on the outer peripheral position of the first rotating body, the first reference detection signal corresponding to this is transmitted from the first rotation sensor to the crankshaft. It is output once per rotation,
In a four-cycle internal combustion engine, the entire stroke of each cylinder is completed by two revolutions of the crankshaft. Therefore, only the first reference detection signal requires a reference position of a specific cylinder (for example, a reference for starting fuel injection) necessary for engine control. Cylinder) cannot be identified. Therefore, in the present invention, when the first reference signal is input, the detection signal from the second rotation sensor provided on the camshaft that makes one rotation by two rotations of the crankshaft is used,
The reference position of the specific cylinder is determined.

In the present invention, the abnormality determination condition for determining the abnormality of the first rotation sensor by the abnormality determination means is that the first detection element detects the first reference position detected portion. The count value of the number of detections of the first rotation angle detected part of
When the number of first rotation angle detected portions formed on the first rotating body does not match, it is set so as to determine the abnormality of the first rotation sensor, and the normal return determination means resets the first rotation sensor to normal. The normal return condition for the determination is set to determine the normal return of the first rotation sensor when the abnormal determination condition is not satisfied or when the cylinder determination means determines the reference position of the specific cylinder. To be done.

As described above, if the return determination condition is the same as the abnormality determination condition, the fail safe control is executed when the abnormality of the first rotation sensor is erroneously determined due to noise or the like. This is because it takes time to determine the normality of the first rotation sensor at the time of starting the internal combustion engine, there is a delay in starting the fuel injection and the like after determining the cylinder, and the startability may deteriorate. In the present invention, when the abnormality determination condition is not satisfied, the normal recovery condition is
By setting two conditions when the reference position of the specific cylinder can be discriminated by the cylinder discriminating means, the internal combustion engine can be promptly started at the time when the cylinder discrimination can be performed at the time of starting the internal combustion engine. .

However, when different conditions are set for the abnormality determination condition and the normal recovery condition as described above, the abnormality determination and the normal determination of the first rotation sensor can be repeated as compared with the case where the same conditions are set. In that case, it is considered that some abnormality has occurred in the first rotation sensor. Therefore, in the present invention, when the abnormality determination by the abnormality determination means and the normal recovery determination by the normal recovery determination means are alternately repeated at a predetermined frequency, the normal condition determination means causes the normal recovery determination means to make the normality of the first rotation sensor normal. By switching the normal recovery condition for determining the recovery to only the non-fulfilled condition of the abnormality determination condition, it becomes difficult for the normal recovery determination means to determine the normal recovery.

As a result, according to the present invention, frequent switching of the normal / abnormal determination result of the first rotation sensor can be prevented, the engine control can be stabilized, and at the same time, the first rotation sensor will not be operated. Despite the anomaly,
It is possible to prevent erroneous determination of normal return. Therefore, according to the present invention, the engine control using the first rotation sensor can be satisfactorily executed, and the safety during the operation of the internal combustion engine can be improved.

As the restoration condition changing means, as described in claim 3, the counting means counts the number of repetitions of the abnormality determination by the abnormality determining means and the normal restoration determination by the normal restoration determining means for each predetermined period. However, when the count value by the counting means becomes equal to or larger than the predetermined value, the normal return condition may be switched.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a configuration of an engine control apparatus of an embodiment that controls a fuel injection amount and the like to a 4-cycle 6-cylinder diesel engine for automobiles (hereinafter simply referred to as an engine).

As shown in FIG. 1, a disk-shaped NE pulser 2 is fixed to the crankshaft 1 of the engine as a first rotating body coaxially therewith. On the outer periphery of the NE pulsar 2, the crankshaft 1 is provided with a first rotation angle every {15 ° A in this embodiment (° CA: crank angle)}.
A plurality of protrusions 3 are formed as rotation angle detection target portions. Then, among the plurality of protrusions 3, a protrusion corresponding to a reference position indicating a top dead center (TDC) of a specific cylinder, for example, the first cylinder and the sixth cylinder, is deleted, and that portion is the first protrusion.
It is a toothless portion 4 as a reference position detected portion. Therefore, a total of 23 protrusions 3 are formed on the NE pulser 2.

On the other hand, on the camshaft 5 that rotates in synchronization with the crankshaft 1 of the engine and rotates once every two rotations of the crankshaft 1, a disk-shaped G pulsar 6 is coaxially provided as a second rotating body. It is fixed. This G pulsar 6
The outer circumference of the cylinder is divided by a predetermined angle corresponding to the number of cylinders (6 cylinders in the present embodiment, so every 60 degrees,
A plurality of (six in this embodiment) protrusions 7 are formed as the second rotation angle detected parts at the crank angle of every 120 ° C.). The plurality of protrusions 7 are formed at a position of 45 ° C. before the top dead center of each cylinder of the engine and act so as to indicate the reference position of each cylinder. Further, immediately before the protrusion 7 corresponding to the reference position indicating the top dead center of the first cylinder, an extra tooth 8 as a second reference position detected portion is formed. In addition, in this embodiment, the extra tooth 8 is 75 before the top dead center of the first cylinder.
It is formed at a temperature of A.

Further, electromagnetic pickups 10 and 12 as a first detection element and a second detection element are arranged near the outer circumferences of the pulsers 2 and 6, respectively. The electromagnetic pickups 10 and 12 are each provided with an electronic control unit (hereinafter, simply referred to as C, which is composed of a microcomputer including a CPU, a ROM, a RAM, etc., via a waveform shaping circuit 15.
16). Hereinafter, the sensor (first rotation sensor) configured by the NE pulser 2, the electromagnetic pickup 10 and the like is referred to as an NE sensor, and the G pulser 6,
A sensor (second rotation sensor) configured by the electromagnetic pickup 12 and the like is called a G sensor.

In the engine control device of this embodiment having the above-described structure, each time the projection 3 of the NE sensor passes the position facing the electromagnetic pickup 10, the NE pulse signal as shown in FIG. Is input to the CPU 16 via the waveform shaping circuit 15. In addition, each time the protrusion 7 and the extra tooth 8 of the G sensor pass the facing position of the electromagnetic pickup 12, a G pulse signal as shown in FIG. 4A is input to the CPU 16 via the waveform shaping circuit 15. .

Based on these input signals, the CPU 16 specifies the cylinder to which fuel should be injected next, and calculates the crank angle and the rotational speed of the engine, and the calculation result and the operating state of the engine. Based on the input signal from the other sensor group 17 for detecting the fuel injection amount,
Computation processing for fuel injection amount control, fuel injection timing control, fuel pressure control, etc., which controls the injection timing, fuel pressure, etc., and controls the actuators such as the injector 18 based on the calculation results. Run.

In FIG. 4, # 1 to # 6 represent the cylinder numbers of the engine cylinders, that is, the first to sixth cylinders, respectively, and the numerical values 0, 120, ...
Crankshaft 1 recognized in the above for various controls
Rotational position, specifically, the crank angle for each engine cycle (that is, for every two rotations) with reference to the top dead center position when the first cylinder # 1 enters the intake stroke.

Further, as is apparent from FIG. 4, in the NE pulser 2 constituting the NE sensor, the NE pulse signal (rising edge) first input to the CPU 16 after the toothless portion 4 passes through the electromagnetic pickup 10, The G sensor is positioned so as to be input to the CPU 16 next to the G pulse signal (rising) input to the CPU 16 at the timing of 45 ° C. before the top dead center of the first cylinder # 1 and the sixth cylinder # 6. There is.

Next, of the processes executed by the CPU 16, the NE interrupt process, which is the main process according to the present invention, will be described with reference to the flow charts shown in FIGS. The NE interrupt process detects the toothless portion 4 of the NE sensor from the input (rising) interval of the NE pulse signal, and the first cylinder # 1 and the sixth cylinder # 6, which are currently near the top dead center, are detected.
Of these, which cylinder is to enter the intake stroke and perform fuel injection after that, in other words, the crankshaft 1
Is a cylinder position determining whether it is a reference position near 0 ° C. (= 720 ° C. A) or a reference position near 360 ° C. shown in FIG. This is a process for determining abnormality, and is executed every time the NE pulse signal is input from the NE sensor (specifically, every time the NE pulse signal rises).

As shown in FIG. 2, when the NE pulse signal is input and the NE interrupt processing is started, first, in S110.
In (S: represents step), the value of the counter CNE that counts the number of inputs of the NE pulse signal is incremented (++ CNE), and in the subsequent S120, the NE pulse signal input this time is the toothless portion of the NE pulser 2. NE missing tooth determination processing is performed to determine whether or not the pulse signal has passed four times (hereinafter, the input of this pulse signal is referred to as missing tooth input).

The NE missing tooth determination process is performed, for example, by
The input interval (in other words, pulse width) T (n) of the NE pulse signal is calculated from the current input time t (n) of the NE pulse signal and the previous input time t (n-1), and this pulse width T (n n) is a predetermined value (eg 3 /
2) It is executed in a procedure such as determining whether or not it is double or more.

Then, in the subsequent S130, the pulse width T
(n) is more than the specified value times the previous pulse width T (n-1),
It is determined whether or not the missing tooth input is determined in the NE missing tooth determination process of S120, and if the missing tooth input is determined, S14 is executed.
If it is determined that the missing tooth input has not been determined, the process proceeds to S24.
Move to 0.

In step S140, the missing tooth determination flag X is reset (0) by the initialization process when the CPU 16 is activated.
By determining whether or not LACK2 is still in the reset state, it is determined whether or not it is the timing at which the missing tooth input is determined for the first time after the CPU 16 is activated. If the missing tooth determination flag XLACK2 is in the reset state, the missing tooth determination flag XLACK2 is set (1) in S150, the process proceeds to S220, and conversely, if the missing tooth determination flag XLACK2 is set, Then, the process proceeds to S160.

In S160, the NE sensor is normal depending on whether or not the value of the counter CNE is a predetermined value (“23” in this embodiment) corresponding to the number of NE pulse signals for one revolution of the crankshaft 1. Determine whether or not. Then, the value of the counter CNE is the predetermined value "23", and
If it is determined that the sensor is normal, the process proceeds to S170,
“NE active” indicating that the NE sensor is normal is stored. Further, in the subsequent S180, a prohibition flag XNE, which will be described later, is set.
NG is reset (0), and the process proceeds to S220.

On the other hand, if it is determined in S160 that the value of the counter CNE is not the predetermined value "23", it is determined that there is some abnormality in the NE sensor or the input system of the NE pulse signal, and S190. Then, it is determined whether or not "NE active" is currently stored. And "N
If "E-active" is stored, then in step S200, within a predetermined period (when the NE pulse signal is 230
The counter CFAIL1 for measuring the number of normal / abnormal inversions of the NE sensor (in other words, the abnormality determination frequency) within the period of individual input is incremented (++ CFAIL).
After 1), the process proceeds to S210. If "NE active" is not stored, the process proceeds directly to S210.
Then, in S210, "N" indicating the abnormality of the NE sensor is displayed.
“E inactive” is stored, and the process proceeds to S220.

Next, in S220, the counter CNE is set.
Is cleared (CNE ← 0), and in the subsequent S230, from the judgment condition preset as the normal recovery condition, the current missing tooth input is 0 ° C. A (= 720) of the crankshaft 1.
℃ A) indicating the reference position around 360 ℃
The determination process shown in FIG. 3 is performed to determine whether it represents a reference position in the vicinity of A or whether the protrusion 3 of the NE pulser 2 is missing. The determination process will be described later.

Then, in S240, it is determined whether or not the value of the counter CFAIL1 representing the abnormality determination frequency of the NE sensor is equal to or more than a predetermined value (for example, "5"), and the value of the counter CFAIL1 is equal to or more than the predetermined value. If there is, S25
At 0, the prohibition flag XNENG for prohibiting execution of the normal return determination in the determination processing of S230 is set (1).
Then, the process proceeds to S260, and if the value of the counter CFAIL1 has not reached the predetermined value, the process proceeds directly to S260.

Next, at S260, the counter C
The value of the counter CFAIL2 that counts the number of inputs of NE pulse signals separately from NE is incremented (++ CFA
IL2), and then at S270, this counter CFAI
It is determined whether or not the value of L2 is equal to or greater than a predetermined value (value “230” in this embodiment).

Then, if the value of the counter CFAIL2 has not reached the predetermined value "230", the processing is ended as it is, and conversely the value of the counter CFAIL2 is changed to the predetermined value "23".
If it is "0" or more, the process proceeds to S280 and the counter CF
Clear AIL1 and CFAIL2 respectively (CFAIL
1, CFAIL2 ← 0), the process is finished.

Next, the determination process executed in S230 will be described. As shown in FIG. 3, in this determination process, first in S310, it is determined whether or not the prohibition flag XNENG is set. If the prohibition flag XNENG is set, the determination process in S320 and subsequent steps is not executed. , The processing is ended as it is, and the above S240 is performed.
On the contrary, if the prohibition flag XNENG is in the reset state, the process proceeds to S320.

In S320, according to the preset determination condition, it is determined whether or not two G pulse signals have been input before the current missing tooth input, so that the crankshaft 1 is currently at 0 ° C. It is determined whether or not it is the reference position corresponding to (= 720 ° C. A).

This judgment condition is that one G pulse signal is input between the time (i-1) when the NE pulse signal was input last time and the time (i) when the NE pulse signal was input this time. In addition, when the NE pulse signal is input, the NE interrupt signal is input three times before the current NE interrupt processing is started (i-3), and the NE pulse signal is input last time (i-). Until 1), when one G pulse signal is input, the reference position of 0 ° C is judged.
It is set in advance.

When it is determined in S320 that this determination condition is satisfied, the process proceeds to S330, in which the crankshaft 1 is currently at the reference position of 0 ° C (= 720 ° A), and then the intake stroke is performed. It is determined that the cylinder to enter and to inject fuel is the first cylinder # 1, and after memorizing this, S
Move to 360.

On the other hand, when it is determined in S320 that the determination condition is not satisfied, the process proceeds to S340, and this time,
According to the preset determination conditions, it is determined whether or not only one G pulse signal is input before the current missing tooth input, so that the crankshaft 1 is currently at 360 ° C.
It is determined whether or not it is the reference position corresponding to A.

This judgment condition is that one G pulse signal is input between the time (i-1) when the NE pulse signal was input last time and the time (i) when the NE pulse signal was input this time. In addition, when the NE pulse signal is input, the NE interrupt signal is input three times before the current NE interrupt processing is started (i-3), and the NE pulse signal is input last time (i-). Up to 1), when the G pulse signal is not input, it is preset to determine the reference position of 360 ° C.

If it is determined in S340 that this determination condition is not satisfied, the current missing tooth input is N
It is assumed that this is due to the lack of the protrusion 3 of the E pulsar 2, and the processing is ended as it is. On the other hand, if it is determined that the determination condition is satisfied, the routine proceeds to S350, where the crankshaft 1 is currently at the reference position of 360 ° C., and then the cylinder to be injected into the intake stroke is the sixth cylinder. After determining that it is # 6 and storing that fact, the process proceeds to S360.

Then, in S360, since the reference position of the crankshaft 1 can be detected by the above processing, N
Assuming that the E sensor is normal, “NE active” is stored and the process ends. That is, as shown in FIG. 4, in addition to the G pulse signal corresponding to the top dead center of each of the cylinders # 1 to # 6, the G sensor outputs the G pulse signal corresponding to the top dead center of the first cylinder # 1. Crank angle (30 ° C
A) Since the G pulse signal from the extra tooth 8 is output at the timing of a minute before, in S320 and S340, the G pulse is output from the time (i-1) immediately before the missing tooth input to the time (i). The top dead center of the 1st and 6th cylinders # 1 and # 6 is confirmed depending on whether or not the signal is input, and further before that (i-
From 3) to time (i-1), it is determined whether the crankshaft 1 is at the reference position of 0 ° C. or not depending on whether the G pulse signal by the extra tooth is input.

In the processes of S320 and S340, if the reference position corresponding to 0 ° C or 360 ° C of the crankshaft 1 can be detected from the input number of the G pulse signal, the above S160- In the processing of S210, even if the NE sensor is once determined to be abnormal and "NE inactive" is stored, in S360, "NE active" is stored as the NE sensor is normal. Thus, the determination state of the NE sensor is returned from "abnormal" to "normal", and the fuel injection control using the NE sensor can be executed.

When the NE sensor abnormality is determined by the processing of S160 to S210, "NE inactive" is stored, and it is determined that the determination condition or is not satisfied in the processing of S320 and S340. Holds "NE inactive" and the NE sensor abnormality determination state continues, but when "NE inactive" is stored in this way, the CPU 16 interrupts the G pulse signal not shown. By the processing, the cylinder discrimination is performed using only the G pulse signal, and the fuel safe injection is performed according to the determination result to continue the operation of the engine and the fail safe control is performed. In other words, in the present embodiment, by executing such fail-safe control, when the NE sensor is abnormal, the engine operation is continued without causing the engine to stop and the traveling safety of the vehicle is ensured.

As described above, in the engine control apparatus according to the present embodiment, the NE sensor abnormality is determined based on the number of NE pulse signals between the missing tooth input and the missing tooth input of the NE sensor. , "NE inactive" indicating that is stored so that it is possible to shift to the fail-safe control for executing the continuous operation of the engine when the NE sensor is abnormal. Even if "active" is stored, if the determination condition or the condition is satisfied by the cylinder determination operation based on the missing tooth input of the NE sensor and the G pulse input state before that, the NE sensor is detected. Promptly restores from "NE inactive" to "NE active" as normal.

As a result, for example, when the protrusion 3 of the NE pulser 2 constituting the NE sensor is missing, a physical abnormality occurs in the NE sensor, "NE inactive" is stored, and thereafter, the above If the determination condition is not satisfied, the fail-safe control when the NE sensor is abnormal can be executed to improve the safety when the vehicle is traveling. Further, for example, when “NE inactive” is temporarily stored even if “NE inactive” is erroneously determined due to external noise or the like, and then the cylinder determination can be normally performed, N
The determination state of the E sensor changes from "NE inactive" to "NE
It is possible to quickly return to "active" and prevent the fail-safe control from being unnecessarily executed.

By the way, as shown in FIG. 5, the NE pulser 2
Of the plurality of protrusions 3 formed on the second and fifth cylinders #
2, the protrusion 3 corresponding to the top dead center of # 5, or the third and fourth
The toothless portion 4 such as the protrusion 3 corresponding to the top dead center of the cylinders # 3 and # 4
120 ° A or 240 ° C for the crank angle position of
In the case where the protrusion 3 formed at the rotational angle position deviated by A is missing, even if the abnormality of the NE sensor is determined and "NE inactive" is stored by the processing of S160 to S210, After that, in the determination process executed in S230, the G pulse signal corresponding to the top dead center of the second and fifth cylinders # 2 and # 5 output from the G sensor, or the third pulse signal
And the G pulse signal corresponding to the top dead center of the fourth cylinder # 3 and # 4, it is determined that the above determination conditions are met, and the NE
The determination state of the sensor will return from "NE inactive" to "NE active". Then, in this case, the crankshaft 1 is erroneously determined to be at the reference position corresponding to 360 ° C., and fuel injection is repeatedly executed to the sixth cylinder # 6, which damages the engine. Will give.

In FIG. 5, 120 ° C. with respect to the toothless portion 4.
The two projections 3 which are misaligned by A and 240 ° C. respectively are missing, and the determination conditions are sequentially established in the vicinity of the top dead center of the second cylinder # to the sixth cylinder to indicate normality / abnormality of the NE sensor. The case where the flag XNEACT is repeatedly inverted to the set state representing "NE active" and the reset state representing "NE inactive" is shown.

However, in this embodiment, as shown in FIG. 5, the counter CFAIL2 repeatedly counts the number of NE pulse signals input from "0" to a predetermined value "230", so that the crankshaft 1 rotates. A determination period (a period in which the crankshaft 1 rotates approximately 10 times) is repeatedly set, and the counter CFAIL1 is used to reverse the determination result of the NE sensor from “NE active” to “NE inactive” within that period. When the number of times is counted and the count value reaches a predetermined value “5”, the prohibition flag XNENG is set to prohibit the judgment as to whether or not the judgment condition, which is a condition for returning to normal in normal times, is satisfied. Even if the determination condition is met, the system is not allowed to return to "NE active", so the erroneous determination of the sixth cylinder is not continued, After the fuel injection into the engine by running at the fail-safe control at the time of the NE sensor abnormality, it is possible to prevent damage to the engine.

Further, the prohibition flag XNENG indicates that the number of NE pulse signals during the missing tooth input becomes a predetermined value "23" and S
It is reset for the first time when "CNE = 23" is determined in 160 (that is, when the abnormality determination condition is not satisfied). Therefore, once the prohibition flag XNENG is set, the engine is then operated again. Never return from "NE inactive" to "NE active"
Fail-safe control can be continued.

Therefore, according to the engine control apparatus of the present embodiment, when the NE sensor can be accurately judged and the cylinder can be discriminated by the NE sensor, the fuel injection control is executed according to the discrimination result and the engine is executed. Normal operation,
When cylinder discrimination cannot be executed by the NE sensor, G
It is possible to continue the operation of the engine by fail-safe control in which a cylinder is discriminated using a sensor, and it is possible to improve the safety and control accuracy of the engine control.

In this embodiment, switching from "NE inactive" to "NE active" (that is, N
Not only when the abnormality determination condition of the NE sensor (NE ≠ 23) is no longer satisfied, but also when the cylinder determination can be executed from the input state of the G pulse signal before the tooth-missing input. When the abnormality determination condition of the NE sensor is satisfied due to noise or the like, the abnormality of the NE sensor is determined and the fail-safe control is executed even though the cylinder determination can be normally performed. This is to prevent it from being lost.

In this embodiment, after the CPU 16 is activated,
If there is a missing tooth input first (S140: NO),
In S150, the tooth-missing determination flag XLACK indicating that fact
Just by setting 2, the process directly proceeds to the determination process of S230, and when it is determined that the determination condition or is satisfied in S230, the normal control is started as it is. If the abnormality determination of the NE sensor is executed after the start of the engine and then the cylinder determination is performed using the determination condition, it is not possible to immediately start the fuel injection immediately after the engine is started and the startability of the engine is reduced. This is because it will decrease. In other words, in this embodiment, after the engine is started, the cylinders can be promptly discriminated and the fuel injection can be started, so that the startability of the engine, especially the startability at the low temperature start, can be secured. is there.

As described above, as one embodiment of the present invention, the abnormality determination of the NE sensor is performed based on the number of pulse signals during the toothless input, and the cylinder determination is performed based on the input state of the G pulse signal before the toothless input. Executed and then returned from the abnormality determination state of the NE sensor to the normal determination state, the cylinder determination is performed when the abnormality determination condition of the NE sensor is no longer satisfied and from the input state of the G pulse signal before the missing tooth input. A case in which the present invention is applied to an engine control device capable of promptly executing cylinder determination using a missing tooth input from the NE sensor to start engine control without a response delay by executing the operation when possible. Although described, the present invention is not limited to such an engine control device and can take various aspects.

For example, in the above embodiment, the engine control device which controls the fuel injection of the 6-cylinder diesel engine has been described, but even the engine control device which controls the fuel injection of the 4-cylinder diesel engine controls the gasoline engine. Even if the engine control device performs (fuel injection control, ignition timing control, etc.), if it is a control device that performs cylinder discrimination using the NE sensor and the G sensor,
The same effect can be obtained by configuring the same as the above embodiment.

Further, the object of abnormality determination may be a sensor other than the NE sensor as in the above embodiment, for example, a G sensor, or another actuator,
The present invention can be applied to any control device that switches between normal control and fail-safe control by performing the abnormality determination and the normal recovery determination.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a configuration of an engine control device according to an embodiment.

FIG. 2 is a flowchart showing an NE interrupt process of the embodiment.

FIG. 3 is a flowchart showing details of determination processing for cylinder determination performed in S230 of FIG.

FIG. 4 is a time chart showing output pulses from the G sensor and the NE sensor and changes in the counter CNE when the NE sensor is normal.

FIG. 5 is a time chart showing an example of the operation when the normality / abnormality determination of the NE sensor is repeated.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Crankshaft 2 ... NE pulser 3 ... Protrusion 4 ... Missing tooth portion 5 ... Camshaft 6 ... G pulser 7 ... Protrusion 8
... Extra teeth 10, 12 ... Electromagnetic pickup 15 ... Waveform shaping circuit 16 ... Electronic control unit (CPU)

Claims (3)

[Claims] 1. An abnormality determining means for determining an abnormality of a control device such as a sensor or an actuator provided in an internal combustion engine for controlling an engine based on an abnormality determining condition set in advance, and the abnormality determining means controls the abnormality. When an abnormality of the device is determined, a predetermined fail-safe control not using the control device is executed, and a normal recovery from the abnormal condition of the control device is determined based on a normal recovery condition set in advance. In a control device for an internal combustion engine, which comprises a determining means, when the normal recovery determining means determines that the control device returns to normal, cancels the fail-safe control and executes normal control using the control device. When the abnormality determination by the abnormality determination means and the normal recovery determination by the normal recovery determination means are alternately repeated at a predetermined frequency, the normal recovery determination means causes the controller to operate. Control apparatus for an internal combustion engine, wherein a normal return condition to determine the normal return, provided the return condition changing means for switching the normal return difficult direction. 2. The control device for an internal combustion engine according to claim 1, wherein the first rotating body rotates in synchronization with the crankshaft of the multi-cylinder four-cycle internal combustion engine, the outer peripheral position of the first rotating body, and the like. A plurality of first rotation angle detected portions formed at angular intervals;
A first reference position detected portion formed at a specific position on the outer peripheral position of the rotating body, and a first signal provided near the rotation locus of each detected portion and generating a detection signal in response to passage of each detected portion A first rotation sensor having a detection element, a second rotating body that rotates in synchronization with the camshaft of the internal combustion engine, and an outer peripheral position of the second rotating body corresponding to the number of cylinders of the internal combustion engine at equal angular intervals. A plurality of second rotation angle detected parts, a second reference position detected part formed at a specific position on the outer peripheral position of the second rotating body, and a rotation locus of each detected part. A second rotation sensor including a second detection element that generates a detection signal in response to passage of each detected portion, and a first reference detection signal corresponding to the first reference position detected portion from the first rotation sensor When input, the detection signal from the second rotation sensor before inputting the signal A cylinder discriminating means for discriminating the reference position of the specific cylinder from the force pattern; the abnormality determining means is configured to detect the first reference position by the first detection element based on a detection signal from the first rotation sensor. The number of detections of the first rotation angle detected part within the period in which the detection part is detected is counted, and when the count value does not match the number of the first rotation angle detected parts, the abnormality determination condition is It is determined that the first rotation sensor is abnormal, and the normal return determining unit determines whether the abnormality determining condition is not satisfied or the cylinder determining unit determines the reference position of the specific cylinder. , Assuming that the condition for returning to normal is satisfied,
When the normal condition of the first rotation sensor is determined to be normal, and the recovery condition changing unit is configured to return the normal condition when the abnormality determination by the abnormality determining unit and the normal return determination by the normal recovery determining unit are alternately repeated at a predetermined frequency. A control device for an internal combustion engine, wherein the determining means switches the normal return condition for determining the normal return of the first rotation sensor only to a state where the abnormality determining condition is not satisfied. 3. The control device for an internal combustion engine according to claim 1 or 2, wherein the recovery condition changing means determines the number of repetitions of the abnormality determination by the abnormality determination means and the normal recovery determination by the normal recovery determination means. Equipped with counting means for counting every predetermined period,
A control device for an internal combustion engine, characterized in that the condition for returning to normal is switched when the count value by the counting means exceeds a predetermined value.