JPH07197838A - Control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide a control device for an internal combustion engine which is constituted to accurately and rapidly execute control of the internal combustion engine after a power source is turned ON and improve startability and emission of the internal combustion engine. CONSTITUTION:A control device for an internal combustion engine has a sensor output state discriminating means 6 comprising a sensor output detecting means 7; a sensor output normal state range setting means 8; a sensor output normal state discriminating means 9; a sampling means 10; a change mount computing means 11 to compute a change amount DELTAV of an effective sensor output value obtained at every sampling period; and a sensor output normal state discriminating means 12 to decide that the output state of the sensor is brought into a normal state when the change amount DELTAV of the sensor output value is decreased to a value lower than a given value Vref.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an internal combustion engine, and more particularly, to control the internal combustion engine at high speed by determining whether the sensor output signal is normal and stable. The present invention provides a control device for an internal combustion engine that can be accurately executed.

[0002]

2. Description of the Related Art Conventionally, various sensors for detecting various control factors have been provided for controlling an internal combustion engine, and each sensor appropriately uses measurement data individually measured and performs a predetermined processing. The internal combustion engine is being controlled while being used as the control data of the internal combustion engine.

For example, when controlling the internal combustion engine, there is an intake air flow rate to the internal combustion engine as an important control factor and control factor, and by appropriately controlling the intake air flow rate in relation to the fuel supply amount. It is possible to improve fuel efficiency and obtain appropriate output power. As a sensor for measuring the flow rate of air flowing into the internal combustion engine, for example, what is called a thermal air flow meter or a hot wire air flow meter is generally used.

Such a thermal air flow meter or a hot wire air flow meter detects an intake air amount by a bridge circuit including an electric heating element of a heating wire and a temperature compensating resistor, and an electric heating element of the heating wire. However, if it does not reach a certain temperature, it will not function properly, so it is necessary to supply a predetermined current to the electric heating element of the heating wire for a certain period when the power is turned on.

As a principle of such a thermal air flow meter, for example, when a heating wire heated to a high temperature, for example, a platinum wire is placed in an air flow, heat corresponding to the flow rate of the air is taken away, and a temperature drop corresponding to that amount is taken. The current is controlled so as to increase the current so as to compensate for the amount, and the actual air flow rate can be measured by measuring the current amount or the voltage amount corresponding thereto.

By the way, as shown in FIG. 11 (A), the conventional thermal air flow meter is characterized in that when the thermal air flow meter is powered on at time t1 and driven. The abnormal voltage Ve is output for a certain period (Tab), and then gradually decreases to the normal voltage Vn to shift to a stable normal output state.

That is, in a conventional thermal type air flow meter, a sensor which is normally used at a temperature of about 200 ° C., and when such a sensor is cold, when the power is turned on, the temperature of the heat wire rapidly increases. Since it is necessary to raise
A large amount of power is consumed, and an abnormal voltage is output during that time. Therefore, the abnormal voltage generation period (Tab) described above
However, the flow rate of intake air flowing into the internal combustion engine cannot be accurately measured. In other words, even if the cranking signal is input during this period and the voltage of the sensor is measured, the internal combustion engine will be controlled based on the abnormal voltage value. Since it is impossible to calculate, the startability and emission of the internal combustion engine deteriorate.

Therefore, in the prior art, in the control means of such an internal combustion engine, when the power is turned on, the output of such a sensor, for example, a thermal air flow meter, is maintained until a certain period of time elapses. A method of prohibiting the use of the above is proposed in, for example, Japanese Patent Laid-Open No. 4-112947 or Japanese Patent Publication No. 3-75740. That is, as shown in FIG. 11 (B), the sensor is turned on for a predetermined time (T
The period during which the abnormality detection is prohibited is set until (dis) elapses, and it is determined whether the sensor output is in the abnormal state or the normal state after time t2 when the predetermined time (Tdis) has passed. It is a thing.

Further, within the predetermined time (Tdis), the fuel injection time or the like is calculated on the basis of the water temperature or the like to execute the control. A predetermined time (T
As described above, the time until (dis) elapses is the period (Ta) in which the thermal air flow meter outputs an abnormal voltage Ve after the thermal air flow meter is powered on.
It is set to be longer than b).

Therefore, when the output of the sensor shows an abnormal state even after the lapse of the predetermined time (Tdis), the output of the sensor is determined to be abnormal, and the predetermined value is obtained as shown in FIG. 11 (C). When the output of the sensor is within the predetermined sensor output normality determination range S after a lapse of time (Tdis), the output of the sensor is determined to be normal.

Among the above-mentioned conventional examples, Japanese Patent Publication No.
The control procedure in the control method of the internal combustion engine proposed in Japanese Patent No. 75740 will be described with reference to FIG. 12. In step (100), when the calculation routine of the fuel injection amount of the internal combustion engine is started, At (102), it is determined whether or not a predetermined period (Tdis) has elapsed after the power is turned on. If NO, the process proceeds to step (108), which is predetermined based on the cooling water temperature and the like. A fuel injection amount of the internal combustion engine is calculated according to a calculation processing program.

On the other hand, in step (102), it is determined that a predetermined period (Tdis) has elapsed after the power was turned on,
If YES, go to step (104), where the sensor,
For example, it is determined whether or not the thermal air flow meter outputs a normal output, and if NO, step (108)
Then, the fuel injection amount of the internal combustion engine is calculated based on the cooling water temperature and the like in accordance with a predetermined calculation processing program, but if YES, the process proceeds to step (106) where the sensor such as the thermal air flow is used. The fuel injection amount of the internal combustion engine is calculated based on the output value of the meter.

Therefore, in such a conventional method, since it is necessary to determine the output state of the sensor after at least the predetermined time (Tdis), the sensor output is in a normal state or abnormal. It took a considerable amount of time to determine if it was in such a state.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems in the prior art and to control the internal combustion engine after turning on a power source for driving a sensor provided in a control system of the internal combustion engine. The present invention provides a control device for an internal combustion engine, which is capable of accurately and rapidly executing the above, and thereby improving startability or emission of the internal combustion engine.

[0015]

In order to achieve the above-mentioned object, the present invention basically adopts the technical constitution as described below. That is, a control device for an internal combustion engine comprising an internal combustion engine, a sensor for measuring data relating to a specific control factor of the internal combustion engine, and control means for controlling an operating state of the internal combustion engine in response to an output of the sensor. In the control means, a sensor output state determination means for determining whether the output state of the sensor is a normal state or an abnormal state is provided, and the sensor output state determination means is the sensor output state determination means. Output detection means for detecting the output of the sensor, a sensor output normal state range setting means for presetting a predetermined range in which the output value of the sensor can be judged to be in a normal state, and the sensor output by the sensor output normal state range setting means. A sensor output normal state determining means for determining whether or not the sensor output is in a predetermined range, and the sensor output is in the sensor output normal state range setting procedure. Sampling means to enable when within the range set at a predetermined sampling period, is measured by the output detecting unit, a measured value of the sensor output by,
A change amount calculating unit for calculating an effective change amount of the sensor output value obtained at each sampling cycle by the sampling unit, and a change amount of the sensor output value obtained by the change amount calculating unit is predetermined. A control device for an internal combustion engine, comprising: a sensor output normal state identifying means for determining that the output state of the sensor is in a normal state when the output value of the sensor is lower than a predetermined value.

[0016]

Since the control device for an internal combustion engine according to the present invention has the above-mentioned technical structure, the output of the sensor is normal after the power is supplied to the sensor in the control system of the internal combustion engine. After confirming that the output value of the sensor is within the range, the output value of the sensor is analyzed, and if the output value shows a predetermined state, the output of the sensor is normal and stable. In the conventional method, the time when the normalization of the sensor can be judged is about 3 seconds after the power is turned on, and it is about 300 ms after the power is turned on. As a result, the required fuel injection amount of the internal combustion engine after the power supply to the control system is turned on can be accurately and promptly executed, and therefore the startability of the internal combustion engine and the internal combustion engine can be improved. Greatly improve the emissions of It is possible.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific example of a control device for an internal combustion engine according to the present invention will be described in detail below with reference to the drawings. Figure 1
FIG. 2 is a block diagram showing a configuration example of a specific example of a control device for an internal combustion engine according to the present invention, and FIG. 2 is a block diagram showing a detailed configuration example of the control means in FIG. 1.

That is, FIG. 1 shows an internal combustion engine 2 composed of an engine and the like, a sensor 3 for measuring data relating to a specific control factor of the internal combustion engine 2, and an internal combustion engine 2 in response to an output of the sensor 3. Control unit 5 provided at a predetermined site
For controlling the operating state of the internal combustion engine 2, and a control device 1 for the internal combustion engine is shown. Further, the control unit 4 indicates the output state of the sensor 3. A sensor output state determination means 6 for determining whether the output is in the normal state or the abnormal state is provided.

Further, FIG. 2 shows a specific example of the configuration of the sensor output state judging means 6, that is, the output detecting means 7 for detecting the output of the sensor 3, and the output of the sensor 3. A sensor output normal state range setting means 8 for presetting a predetermined range in which the value can be judged to be in a normal state, and an output of the sensor 3 is the sensor output normal state range setting means 8
The sensor output normal state determination means 9 for determining whether or not the sensor output is in the predetermined range S set by the sensor output normal state range setting means 8 is within the range S set by the sensor output normal state range setting means 8. In some cases, it is measured by the output detection means 7 at a predetermined sampling period,
Sampling means 10 for validating the measured value of the sensor output, change amount calculating means 11 for calculating the change amount ΔV of the effective sensor output value obtained by the sampling means 10 at each sampling cycle, the change amount calculating means. 11
And a sensor output normal state identifying means 12 for determining that the output state of the sensor 3 is in a normal state when the variation amount ΔV of the sensor output value obtained in the above step becomes lower than a predetermined value Vref. It is composed of

That is, in the present invention, in order to improve the conventional problems and complete the determination of the normal state of the output value of the sensor 3 more quickly, as a result of earnest study, the voltage which is the output value of the sensor 3 is determined. Paying attention to the point that the value gradually decreases with the passage of time from the abnormal state, and when the falling voltage approaches the stable state, it is determined that the output value of the sensor 3 is in the normal state. It was learned that the judgment in normal time can be carried out quickly.

The specific control factor of the internal combustion engine used in the control device for the internal combustion engine according to the present invention is not particularly limited, but is, for example, the intake air flow rate taken into the internal combustion engine. You can also do things. Further, when the specific control factor used in the control device for the internal combustion engine in the present invention is the intake air flow rate, the sensor needs to have a function of detecting the intake air flow rate. Specifically, for example, a sensor generally called a thermal air flow meter or a hot wire air flow meter can be used.

When using such a sensor, the output value from the sensor is preferably a voltage value. Next, the operation principle of the sensor output state judging means 4 used in the control method of the control device 1 for the internal combustion engine according to the present invention will be described with reference to FIG.
Referring to FIG. 11, the output value characteristic of the thermal air flow meter has the waveform as described with reference to FIG. 11 (A), and therefore the output detecting means 7 at time t1. When the power is turned on,
A waveform W similar to that of 1 (A) is shown.

Therefore, in the present invention, the range S in which the output value of the sensor 3 is expected to be in a normal state is preset by the sensor output normal state range setting means 8 as shown in FIG. I'll do it. The range S is set to a different value for each sensor depending on the form, configuration, etc. of the sensor used, but an appropriate range S is determined by conducting an experiment etc. in advance for each sensor. I can do things.

Next, at a time t2 when a predetermined time has elapsed from the time t1 when the power was turned on, an arithmetic processing circuit for driving the sensor output state judging means 4, for example, a CPU.
To start. (See the waveform W1 in FIG. 3) The delay interval between the times t1 and t2 can be set as appropriate, and as described above, the output value of the sensor is shorter than the period Tab showing the abnormal state. It is desirable to set the time.

In some cases, the CPU start time t
It goes without saying that 2 may be the same as the power-on time t1. In this step, specifically, the counter described later is reset and the sampling means 10
The operation of detecting the output of the sensor at a predetermined sampling cycle f is started, and at the same time, the counter increments or decrements the count value of the counter in synchronization with the sampling cycle f.

In such a situation, since the output value of the sensor is plotted outside the normal range S of the sensor output, in this state, the output value of the sampled sensor is not validated and is determined to be a predetermined value. It is desirable not to store in the storage means of. However, in the present specific example of the present invention, when the main purpose is to detect a normal state of the sensor output value, the above operation is sufficient, but an abnormal state of the sensor output value is also detected. It is desirable to store the sensor output value in such a state in the case of performing analysis.

Further, in such a state, the output value of the sensor and the upper limit value S1 of the sensor output normal state range S are set.
Is compared and calculated by the sensor output normal state determination means 9 described above.
Since there is an abnormal condition, no control signal is output. After that, when the output value of the sensor 3 gradually decreases and enters the above-described normal sensor output state S at time t3, the normal sensor output state determination means 9 causes A signal indicating that the output value of the sensor has entered a region that can be judged to be normal is output, and based on this, the CPU described above outputs the signal from the sensor 3 as shown by the waveform W2 in FIG. The normal judgment start permission flag for the output value of is output.

When the normal determination start permission flag is set, the sensor output value sampled by the output detecting means 7 is determined to be valid and stored in a predetermined storage means. Next, after time t3, the sensor output value V sampled at the above-described predetermined sampling cycle is attached, and the sensor output value change amount ΔV at each sampling time point is calculated as the change amount calculation means 11
And is stored in an appropriate storage means.

The method of calculating the sensor output value change amount ΔV is not particularly limited, but for example, the sensor output value V1 detected in the previous sampling cycle and the sensor output value V2 detected in the next sampling cycle are used. The difference may be the sensor output value change amount ΔV. In the present invention, such an operation is repeated, but during that time, the sensor output normal state identifying means 12 constantly compares the sensor output value change amount ΔV and a predetermined value Vref. Processing is performed, and at time t4,
When the sensor output value change amount ΔV becomes lower than the predetermined value Vref set in advance, that is, when ΔV <Vref, the output value of the sensor 3 becomes normal and stable. It is something that is judged.

In such a situation, the CPU determines that the sensor output value normality flag is set, as indicated by the waveform W3 shown in FIG. 4 and 5 show diagrams in which the operation of the counter means 13 is added to the operation principle of the sensor output state judging means 6 according to the present invention shown in FIG.

That is, the counter means 13 used in the present invention starts the counting operation in synchronization with the power-on signal to the sensor 3 or after a predetermined delay time has elapsed, and outputs the output value of the sensor. Is to continue the counting operation while deviating from the predetermined range set by the sensor output normal state range setting means, and further, the counter means 13 is provided in the counter means 13. A sensor output abnormal condition notification signal generating means for notifying an abnormal condition of the sensor output when the integrated count value exceeds a predetermined value N or becomes equal to or less than a predetermined value N. And 14 are provided.

That is, the counter means 1 according to the present invention.
3 is also called an abnormality counter. 4 and 5 illustrate an example in which the counter means 13 starts the counting operation at the same time when the sensor 3 is turned on, but in FIG. The unit 13 increments or decrements the integrated count value of the counter unit 13 by 1 for each sampling cycle, and the counting operation of the counter unit 13 is performed by the sensor output described above. The output value of the sensor output from the normal state determination means 9 is continued until a signal indicating that the sensor has entered the area determined to be normal is output.

Therefore, unless the above signal is output,
The counter 13 continues the counting operation. In FIG. 4, at time t3, a signal indicating that the output value of the sensor has entered a region judged to be normal is output, so the counting operation of the counter means 13 is as follows. Since the counter means 13 is reset at that point and the counter means 13 is reset, no abnormality alarm is output.

On the other hand, in FIG. 5, since the sensor output value continues to be in an abnormal state, a signal indicating that the output value of the sensor has entered a region judged to be normal is output. Therefore, if the integrated count value of the counter means 13 exceeds a predetermined value N at time t5 or becomes equal to or less than a predetermined value,
An abnormal alarm is output from the sensor output abnormal condition notification signal generating means 14 which notifies the abnormal condition of the sensor output.

In the control device for an internal combustion engine according to the present invention, before the output value of the sensor falls within the range S set by the sensor output normal state range setting means 8. In the state of 1), that is, the state before time t3, a predetermined set value (default value) unrelated to the sensor output value, for example, an optimum basic injection amount at the time of starting an internal combustion engine such as an engine is set to a predetermined value (default value). Value), perform temperature correction to the basic injection amount by water temperature, etc.,
It may be one that determines the final fuel injection amount.

According to the control method of the control device for an internal combustion engine of the present invention, the normal state of the sensor output value can be judged remarkably quickly as described above as compared with the conventional method. , Such a sensor 3 such as a thermal air flow meter
However, even if it is in a sufficiently hot state, that is, as shown in FIG. 6, or even if the output value of the sensor 3 sticks to the upper limit value or the lower limit value, the amount of change in the sensor output can be reduced by the conventional method. Since ΔV is 0, it is judged that the sensor output value is abnormal. However, in the present invention, it is possible to judge that the sensor output value is normal even in such a situation.

Further, as shown in FIG. 7, even if the power is momentarily cut off during the operation of the engine or the like, it is possible to return to the normal state display in a short period of time. Next, an example of use of the control device for an internal combustion engine according to the present invention mounted on an actual engine will be described with reference to FIG. That is, FIG. 8 schematically shows an electronically controlled fuel injection type internal combustion engine equipped with an embodiment of the control apparatus for an internal combustion engine of the present invention. In this figure, a hot-wire air flow meter 23 is provided in an intake passage 22 of an engine 21. The air flow meter 23 has an analog output, and a bridge circuit is assembled with platinum (Pt) heat wire resistance, temperature compensation resistance, and the like. Then, the current is controlled so as to keep the temperature of the heating wire that changes depending on the air flow rate constant, and this current is taken out as a voltage. The output of the heating wire type air flow meter 23 is the A / D converter of the control circuit 30. Input to the battery 16 via an ignition switch (IG) 35.
It is connected to the.

A throttle opening sensor 39 for detecting the opening of the throttle valve 18 is provided on the shaft of the throttle valve 18 provided in the intake passage 22 of the engine body 1. In the intake passage 22 on the downstream side of the throttle opening sensor 39, a fuel injection valve 27 for supplying pressurized fuel from the fuel supply system to the intake port is provided for each cylinder.
Further, on the upstream side of the air flow meter 23 in the intake passage 22,
Alternatively, a temperature sensor 37 for measuring the intake air temperature or the outside air temperature is provided in any one of the engine main body 21. The output of the temperature sensor 37 is input to the A / D converter 101 of the control circuit 30.

The distributor 24 has a crank angle sensor 25 whose axis converts the crank angle (CA) to generate a reference position detecting pulse signal at every 720 ° CA, and at a predetermined angle (for example, every 180 ° CA). Is provided with a crank angle sensor 26 for generating a reference position detecting pulse signal. The pulse signals of the crank angle sensors 25 and 26 act as a fuel injection timing interrupt request signal, an ignition timing reference timing signal, an interrupt request signal for fuel injection amount calculation control, and the like. These signals are supplied to the input / output interface 102 of the control circuit 30, of which the output of the crank angle sensor 26 is supplied to the interrupt terminal of the CPU 103.

A water temperature sensor 29 for detecting the temperature of the cooling water is provided in the cooling water passage 28 of the cylinder block of the engine 21. The water temperature sensor 29 generates an electric signal of analog voltage according to the temperature TNW of the cooling water. This output is also supplied to the A / D converter 101. An exhaust system downstream of the exhaust manifold 31 is provided with a three-way catalytic converter 32 that simultaneously purifies three harmful components NC, CO, and NO _x in the exhaust gas. Also,
An O ₂ sensor 33, which is a type of air-fuel ratio sensor, is provided on the exhaust pipe 34 on the downstream side of the exhaust manifold 31 and on the upstream side of the catalytic converter 32. The O ₂ sensor 33 generates an electric signal according to the oxygen component concentration in the exhaust gas. That is, the O ₂ sensor 33 supplies different output voltages to the A / D converter 101 via the signal processing circuit 111 of the control circuit 30 depending on whether the air-fuel ratio is on the rich side or the lean side with respect to the theoretical air-fuel ratio. . Further, the input / output interface 102 is supplied with an ON / OFF signal of the IG 15.

In the above configuration, when the IG 15 is turned on, electric power from the battery 16 is supplied to the air flow meter 23 and the control circuit 30 to activate them.
The air flow meter 23 starts output, the control circuit 30 starts a program, takes in output from the air flow meter 23 and other sensors, and controls the injector 27 and other actuators.

The control circuit 30 is constituted by using, for example, a microcomputer, and has a ROM in addition to the A / D converter 101, the input / output interface 102, the CPU 103 described above.
104, RAM 105, backup RAM 106 and the like that retains information even after the IG 15 is turned off are provided.
These are connected by a bus 113. This control circuit 3
At 0, the drive circuit 110 is for controlling the fuel injection valve 27. That is, the fuel injection amount TAU is calculated by correcting the basic injection amount Tp calculated from the intake air amount and the engine speed in the operating state of the engine, and the drive circuit 110 energizes the fuel injection valve 7 by the fuel injection amount TAU. Therefore, the amount of fuel corresponding to the fuel injection amount TAU is sent to the combustion chamber of the engine 21.

Next, the operation procedure of the sensor output state judging means 6 used in the control device for the internal combustion engine according to the present invention will be described with reference to the flow chart shown in FIG. That is, FIG. 9 is a flowchart showing the normality determination routine. When the 8 ms process is started in step 200, it is determined in step 202 whether the sensor output value V is in the normal range S or not. If the sensor output value V is within the normal range S, the start permission flag is set in step 204 and the abnormality counter 13 is reset. If the sensor output is not within the normal range S, the abnormality counter 13 is counted in step 214. In step 206, the abnormality counter 13 sets the predetermined value N.
If so, the sensor abnormality flag is set in step 216, the sensor normal flag is reset, and the process ends. On the other hand, if the abnormality counter 13 is less than the predetermined value N, the process proceeds to step 208 and it is determined whether the start permission flag 1 is set. If the start permission flag is not 1, the process ends. If the start permission flag is 1, the process proceeds to step 210, and it is determined whether or not the variation amount ΔV of the sensor output voltage for each sampling period f is less than or equal to a predetermined value Vref. If ΔV is larger than the predetermined value Vref, the process ends. If ΔV is less than or equal to the predetermined value Vref, step 2
12, the sensor normal flag is set and the sensor abnormal flag is cleared.

FIG. 10 is a flow chart showing the injection calculation routine in the present invention. When the processing by rotation synchronization is started in step 300, it is determined in step 302 whether the sensor normal flag is 1. If the sensor normality flag is 1, the basic injection amount is calculated from the output voltage of the sensor in step 304, and the process proceeds to step 306. If the sensor normality flag is not 1, the basic injection amount is set to a predetermined value (default value) in step 310 and step 30
Go to 6. A correction value such as the water temperature is calculated in step 306, and the final fuel injection amount is calculated in step 308.

[0045]

The control device 1 for an internal combustion engine according to the present invention is
Since it has the configuration as described above,
It is possible to more quickly determine that the output value of the sensor is normal, and in the conventional method, when determining whether the output value of the sensor is normal, it is normal Although it took 3 seconds, in the present invention, it is possible to greatly shorten it.

As a result, the startability or emission of the internal combustion engine can be improved, and an excellent effect can be exerted in purifying exhaust gas at the time of starting.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of a configuration of a specific example in a control device for an internal combustion engine according to the present invention.

FIG. 2 is a block diagram showing a configuration example of a specific example of the sensor output state determining means according to the present invention.

FIG. 3 is a block diagram illustrating the operating principle of the sensor output state determination means used in the control device for an internal combustion engine according to the present invention.

FIG. 4 is a time chart explaining the operating principle of the sensor output state determination means in the present invention.

FIG. 5 is another time chart for explaining the operating principle of the sensor output state judging means in the present invention.

FIG. 6 is a diagram showing an example of a control environment to which a control device for an internal combustion engine according to the present invention can be applied.

FIG. 7 is a diagram showing an example of another control environment to which the control device for an internal combustion engine according to the present invention can be applied.

FIG. 8 shows a control device for an internal combustion engine according to the present invention,
It is a figure explaining a specific example when mounted in an actual engine.

FIG. 9 is a flowchart illustrating an operation procedure of a sensor output state determination means in the control device for an internal combustion engine according to the present invention.

FIG. 10 is a flowchart illustrating another operation procedure of the sensor output state determination means in the control device for the internal combustion engine according to the present invention.

FIG. 11 (A) to FIG. 11 (C) are views for explaining problems of a conventional control device for an internal combustion engine.

FIG. 12 is a flowchart illustrating an example of a control method of a conventional control device for an internal combustion engine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Control apparatus for internal combustion engine 2 ... Internal combustion engine 3 ... Sensor, thermal air flow meter 4 ... Control means 5 ... Control part 6 ... Sensor output state determination means 7 ... Output detection means 8 ... Sensor output normal state range setting means 9 ... Sensor output normal state determination means 10 ... Sampling means 11 ... Sensor output value change amount calculation means 12 ... Sensor output normal state identification means 13 ... Counter means 14 ... Sensor output abnormal state notification signal generation means

Claims (7)

[Claims] 1. An internal combustion engine comprising an internal combustion engine, a sensor for measuring data relating to a specific control factor of the internal combustion engine, and control means for controlling an operating state of the internal combustion engine in response to an output of the sensor. In the control device, the control means is provided with a sensor output state determination means for determining whether the output state of the sensor is in a normal state or an abnormal state, and the sensor output state determination means is An output detection means for detecting the output of the sensor, a sensor output normal state range setting means for presetting a predetermined range in which the output value of the sensor can be judged to be in a normal state, and a sensor output normal state range for the sensor output. Sensor output normal state determination means for determining whether or not it is included in the predetermined range set by the setting means, the sensor output is in the sensor output normal state range Sampling means for validating the measured value of the sensor output measured by the output detecting means at a predetermined sampling period when the value is within the range set by the setting means, and each sampling by the sampling means Change amount calculating means for calculating the effective change amount of the sensor output value obtained in each cycle, and the change amount of the sensor output value obtained by the change amount calculating means becomes lower than a predetermined value. A control device for an internal combustion engine, comprising: a sensor output normal state identifying means for determining that the output state of the sensor is in a normal state. 2. The control device for an internal combustion engine according to claim 1, wherein the specific control factor of the internal combustion engine is an intake air flow rate to the internal combustion engine. 3. The control device for an internal combustion engine according to claim 1, wherein the sensor is a thermal air flow meter. 4. The control device for an internal combustion engine according to claim 1, wherein the output value of the sensor is a voltage value. 5. The sampling means, after a predetermined delay time has elapsed after the sensor was powered on,
The control device for an internal combustion engine according to any one of claims 1 to 4, wherein a sampling operation is started. 6. While the counting operation is started in response to a power-on signal for the sensor, and the output value of the sensor deviates from a predetermined range set by the sensor output normal state range setting means. , The counter means for continuing the counting operation, and when the integrated count value of the counter means exceeds a predetermined value or is equal to or less than a predetermined value, the sensor output The control device for an internal combustion engine according to any one of claims 1 to 5, further comprising: a sensor output abnormal condition notification signal generating means for notifying an abnormal condition. 7. The sensor output value, in a state before the output value of the sensor is included in the range set by the sensor output normal state range setting means, in the control means. 7. The control device for an internal combustion engine according to claim 1, further comprising a control circuit for controlling the internal combustion engine based on an unrelated predetermined set value.