JPH1198894A - Controller for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To recover control autonomously by controlling a drive means such that all exciting signals fed to the stepping motors of a gas flow rate regulation valve are in-phase during a period for detecting an abnormality on a signal line for transmitting the exciting signal thereby preventing the unintended operation of the valve. SOLUTION: An input circuit 191 receives an input signal 190 and removes noise components therefrom before it is converted into a digital data at an A/D converting section 192. Operation results from a central operating section 193 are outputted, as a control output signal 197, through an output circuit 196. The output signal 197 includes control signals SO for fuel injector, ignition coil and ignition plug and a drive circuit 197 drives each stepping motor according to the driving signal SO and monitors the voltage Sm on the transmission line. When the signal line is abnormal, a controller determines whether a decision was made that the signal line was abnormal in the previous processing and makes a decision that the signal line is abnormal it the waiting time variable is higher than a specified value before starting abnormal time processing. According to the arrangement, normal control can be started autonomously upon recovery from abnormality.

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 which controls a gas flow control valve using a stepping motor, and more particularly to an internal combustion engine having a function to cope with an abnormality in a signal line of the stepping motor. Related to a control device for a vehicle.

[0002]

2. Description of the Related Art A gas flow control valve using a stepping motor is, for example, in an automobile, an idle speed control valve (ISC valve) for bypassing a throttle valve to adjust an intake air amount at idling, and an exhaust recirculation control valve. (EGR valve) and a canister purge control valve (CP valve) for adjusting the amount of fuel vapor stored in the charcoal canister to be sucked into the engine.

According to such a gas flow control valve,
By controlling the driving of the stepping motor by the multi-phase excitation signal, the opening of the valve can be accurately and reliably adjusted. When the stepping motor has four phases, for example, the valve is driven by changing the pattern of the excitation signal of each phase with the pattern shown in FIG.

However, when the supply of the excitation signal to some of the phases is stopped due to the disconnection, the valve is driven in a direction opposite to the direction intended by the control device, and the internal combustion engine is brought into an abnormal operating state. Could be. For example, when the coil of the same phase out of the four phases is disconnected in two phases, as shown in FIG.
Only the external force determines the opening and closing direction of the valve.

In order to avoid such an abnormality, a control device for controlling the supply of the excitation signal to the stepping motor detects an abnormality (such as disconnection) of the signal line, and supplies the excitation signal when the abnormality is detected. Some have a function to stop for all phases.

FIG. 11 shows an example of a configuration corresponding to one phase of a stepping motor of a control device having such a function. The excitation signal (current) of the coil L1 of the stepping motor is switched by turning on and off the output transistor T1. When the drive signal So is at a high level, the transistor T1 turns on and the output voltage goes to a low level. That is, if the signal line is normal, the drive signal So
And the output voltage monitor signal Sm, as shown in FIG.
When one is at a high level, the other is at a low level. Here, for example, the signal line Pa-Pb
If a disconnection occurs between the output voltage monitor signals S
m is constant at the low level as shown in FIG. When detecting that the drive signal So and the output voltage monitor signal Sm do not have opposite phases, the control device cuts off the exciting currents of all phases of the stepping motor and stops the operation of the stepping motor. Then, when the abnormality of the signal line of the stepping motor is restored, the control device returns to the normal control in response to the reset operation performed by the repairer.

[0007]

Although the reset operation of the control device is described in a manual issued by an automobile manufacturer, there is no guarantee that all repairers will recognize the reset operation and perform repair. In particular, when the repair is performed at a place other than the authorized factory of the automobile manufacturer, since the reset operation is not recognized, it is determined that there is another cause that the control device does not return to the normal control state after the repair, It is highly likely that unnecessary inspections and repairs will be made.

Further, even in a state where there is no abnormality in the signal line, if the connector of the signal line is once disconnected for some reason, the control device determines that the connection is broken, and cuts off the exciting currents of all phases of the stepping motor. I will. It should be noted that a similar state occurs when the signal line is temporarily disconnected due to vibration or the like or when high-level noise is continuously generated. Even in such a case, unnecessary inspection or repair may be performed without knowing the cause.

Therefore, the control device is required to have a function of detecting that the abnormality of the signal line has been restored. However, in the above-described conventional control device, after detecting the signal line abnormality,
Since the exciting currents of all phases are cut off, it is impossible to verify by itself whether the signal lines have returned to normal. That is, in this control device, the drive signals So of all phases are set to Lo.
Since the w level is fixed, it cannot be verified whether or not the drive signal So and the output voltage monitor signal Sm have an opposite phase relationship. Of course, when the signal line is restored, it is not possible to autonomously return to the normal control.

An object of the present invention is to prevent the air flow regulating valve from performing an unintended operation due to a signal line abnormality of a stepping motor, and to return to normal control autonomously when the signal line abnormality is restored. An object of the present invention is to provide a control device for an internal combustion engine that is enabled.

[0011]

To achieve the above object, the present invention provides at least one gas for an intake system or an exhaust system of an internal combustion engine using a stepping motor driven by a plurality of excitation signals. A control device for an internal combustion engine connected to a flow control valve to control an operation state of the internal combustion engine, wherein a driving unit for supplying an excitation signal to the stepping motor, and whether a signal line transmitting the excitation signal is abnormal A signal line diagnostic means for detecting based on the state of the excitation signal, and a control means for adjusting the opening of the gas flow rate adjustment valve by controlling the driving means, the control means, At least during the period when the signal line diagnostic means detects a signal line abnormality, all of the excitation signals supplied to the stepping motor of the target gas flow control valve are in phase with each other. To provide an internal combustion engine control apparatus characterized by controlling said driving means so that the signals.

In such a control device for an internal combustion engine, all of the excitation signals supplied to the stepping motor of the target gas flow control valve are in phase with each other while the signal line diagnostic means detects the abnormality of the signal line. As a result, the stepping motor is stopped, and the signal line diagnostic means can detect the recovery of the signal line abnormality.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an entire configuration of a system to which a control device for an internal combustion engine according to a first embodiment of the present invention is applied. In the figure, 1 is an internal combustion engine, 1d is an intake pipe,
1e is an exhaust pipe, 2 is a rotational speed sensor, 3 is a coolant temperature sensor, 4 is an intake pipe pressure sensor, 5 is a throttle opening sensor, 6 is a control device, 7 is an air-fuel ratio sensor, 8 is a fuel injection valve, and 9 is Spark plug, 10 is a stepping motor type IS
A C valve, 11 is a fuel tank, 12 is a charcoal canister, 13 is a stepping motor type CP valve, and 14 is a stepping motor type EGR valve.

As shown, a cylinder of the internal combustion engine 1 has a combustion chamber 1c composed of a piston 1a and a cylinder 1b, and an intake pipe 1d and an exhaust pipe 1e are connected to an upper portion of the combustion chamber 1c. ing. A fuel tank 1 is provided in the intake pipe 1d.
, A stepping motor type ISC valve 1 for injecting fuel supplied from a fuel supply system comprising
0, a stepping motor type CP valve 13 and a stepping motor type EGR valve 14 are arranged, an ignition plug 9 is arranged in the combustion chamber 1c, and a catalyst device 15 is arranged in the exhaust pipe 1e. Further, the internal combustion engine 1 includes:
A rotational speed sensor 2, a cooling water temperature sensor 3, an intake pipe pressure sensor 4, and a throttle opening sensor 5 as operating state detecting means for detecting an operating state of the internal combustion engine 1 are arranged.

The control device 6 takes in detection signals from operating state detecting means, which are the aforementioned various detection sensors, and based on the detection results, a fuel injection injector 8, an ignition coil (not shown), a spark plug 9, ISC valve 1
Control 0 etc. Further, the control device 6 has a function of diagnosing the presence or absence of a signal line abnormality of the stepping motor and switching a pattern of a pulse signal to be output according to the diagnosis result.

As shown in FIG. 2, the control device 6 includes an input circuit 191, an A / D converter 192, a central processing unit 193,
OM 194, RAM 195, output circuit 196, and
The driving circuit 197 can be used.

The drive circuit 197 has the configuration shown in FIG. 11 for each stepping motor, corresponding to the number of phases. The drive circuit 197 drives each stepping motor according to the supplied drive signal S0, and monitors the voltage Sm of the transmission line of the drive signal.

The input circuit 191 receives the input signal 190, removes noise components from the signal, and outputs the signal to the A / D converter 192.
The input signal 190 includes a detection signal from the coolant temperature sensor 3, the intake pipe pressure sensor 4, the throttle opening sensor 5, the air-fuel ratio sensor 7, and a monitor signal Sm from the drive circuit 197.

The A / D converter 192 converts a signal input to the input circuit 191 into digital data. This conversion result is temporarily stored in the RAM 195 and is used for the processing of the central processing unit 193.

The central processing unit 193 executes the above-described various controls and diagnoses by executing a program stored in the ROM 194. In this processing, the central processing unit 193 takes in the conversion result of the A / D conversion unit 192, performs calculation, and temporarily stores the calculation result in the RAM 195.

The calculation result is output as a control output signal 197 through an output circuit 196. This output signal 19
7 includes a control signal to the fuel injector 8, the ignition coil, and the ignition plug 9, and a control signal S0 to the drive circuit 197.

At the time of normal operation, the central processing unit 193 operates as shown in FIG.
The opening degree of the valve is adjusted by controlling the energization state of each phase of the stepping motor in the normal pattern shown in FIG. When the abnormality of the signal line is detected, the energization state of each phase is switched to the abnormality pattern shown in FIG. 3B, and the stepping motor is kept stopped.

The central processing unit 193 also performs a calibration process for calibrating a difference between the valve opening which is recognized by itself and the actual valve opening. In this calibration process, when the engine is started or when the signal line is restored from an abnormal state, the stepping motor is once driven by an amount sufficient to fully open or fully close the valve, and the valve position at this time is set as a reference position, and the subsequent steps are performed. Drive control is performed.

The central processing unit 193 uses the control parameters stored in the ROM for control processing. This control parameter is determined as an optimal value at the time of design,
Actually, the value is not always appropriate due to variations in characteristics of manufactured engines, valves, and the like. For this reason, the central processing unit 193 calculates the control state recognized by itself and the detection results of the various sensors 3, 4, 5, and 7, and performs a learning process for setting control parameters to more appropriate values. . In the learning process, a correction amount of the control parameter is calculated and stored in a flash memory or the like. Central processing unit 19
The control unit 3 reads the correction amount at the start of operation, corrects the control parameters, and then performs drive control.

The configuration of the control device 6 is not limited to the above. More functions of the control device 6 may be realized by hardware circuits other than the central processing unit 193. For example, the diagnostic function of the signal line
97 may be provided. Further, the driving circuit 197
May be arranged outside the control device.

FIG. 4 shows an example of a cross section of a stepping motor type valve. The air flow is controlled by the valve 20 and the seat 2
It is adjusted according to the area of the gap with 1. An excitation pulse signal having a pattern as shown in FIG. 3 is supplied to the coil 22 of the stepping motor via the drive electrode 23. The supply of the excitation pulse signal causes the rotor 24 to rotate, and the shaft 25 to move in the longitudinal direction. Thereby, the valve 20
The gap area between the seat and the seat portion 21 is adjusted, and the air flow rate is changed.

Although not shown, in the stepping motor type valve, the valve is closed by a spring (the seat portion side).
There is a thing of the structure which urges. This type of valve is automatically fully closed when the excitation signal is not energized. Conversely, there is also a valve having a structure in which the valve is biased to the open side (the side opposite to the seat portion side) by a spring. This type of valve is automatically fully opened when no current is supplied.

As shown in FIG. 5, in the stepping motor, as the duty ratio of the abnormal pattern (the ratio of the energizing time occupying one cycle) increases, the coil temperature rises sharply. From the characteristics shown, the duty ratio is 50%.
If it is less than, even if the pattern at the time of abnormality is continuously output,
It turns out that the coil temperature does not exceed the allowable temperature. However,
The energization time needs to be longer than the time required for the central processing unit 193 to detect abnormality and normality of the signal line.
For this reason, in the present embodiment, as shown in FIG.
The duty ratio is set to 40% by repeating the pattern at the time of abnormality in 1,1,0,0,0.

FIG. 6 is a flowchart showing a stepping motor drive control process performed by the central processing unit 193 of the control device 6. The illustrated processing is executed for each pulse motor at regular time intervals.

First, the central processing unit 193 of the control device 6
Output the drive pattern to be output this time (Step 3
0). Next, the monitor signal Sm is fetched from the monitor drive circuit (step 3), and the output drive pattern is compared with the monitor signal Sm (step 32). Then, it is checked whether or not both signals have an opposite phase (phase inversion) (step 33). Here, the two signals have opposite phases only when the signal line between the stepping motor and the signal is normal. The above processing is performed individually for all phases of the pulse motor.

If the signal line is normal (step 33, Ye
s) Subsequently, the control device 6 checks whether or not normality has been determined in the previous processing (step 37). If normality has not been determined, the value of the waiting time variable becomes equal to or greater than a predetermined value. (Ie, whether a predetermined waiting time has elapsed) (step 38). If the value of the waiting time variable is less than the predetermined value, the value of the waiting time variable is incremented (step 39), and the process is terminated.

If it is determined in step 38 that the value of the waiting time variable is equal to or greater than the predetermined value, the normality is determined because the waiting time has elapsed (step 40). Then, it is verified whether or not the calibration has been performed after the normality determination (Step 4).
1) If it has been executed, the normal output pattern is output (step 43); if not, the abnormal pattern is output (step 42), and the process is terminated. When the normality is determined in the above step 37, the process proceeds to the above step 41.

If the signal line is abnormal (step 33, N
o) Subsequently, the control device 6 checks whether or not an abnormality has been determined in the previous processing (step 34). If no abnormality has been determined, the value of the waiting time variable becomes equal to or greater than a predetermined value. (That is, whether a predetermined waiting time has elapsed) (step 35). If the value of the waiting time variable is less than the predetermined value, the value of the waiting time variable is incremented (step 36), and the process is terminated.

If it is determined in step 35 that the value of the waiting time variable is equal to or greater than the predetermined value, the waiting time has elapsed, so that an abnormality is determined (step 40), and an abnormal time pattern is output (step 42). , And the process ends. If it is determined in step 34 that the abnormality has not been determined, the process proceeds to step 45.

By repeating the above-described processing at regular time intervals, the normal pattern shown in FIG. 3A is output during normal control, and the abnormal pattern shown in FIG. Is output. The control device 6 can prevent the stepping motor from rotating in an unintended direction when the signal line is abnormal by performing the switching of the drive pattern, and can start the normal control autonomously after the abnormality is recovered. it can.

The reason why the waiting time is checked in the steps 35 and 38 is to prevent erroneous determination due to noise or the like by making a determination based on a plurality of detection results. With this function, the control device can determine the occurrence of the abnormality and the recovery from the abnormality with high accuracy.

In steps 41 and 42, the abnormal pattern is output even after the normality is determined and before the calibration process is performed, because the abnormal state of the signal line and the like are recognized by the state of the valve recognized by the control device. This is to prevent normal drive control from being performed in a state where there is a large deviation from the actual valve state, and to prevent abnormal drive control from being performed. Next, another example of drive control of the stepping motor will be described with reference to FIGS.

FIG. 7 shows a flowchart of the drive control process for the ISC valve 10. Here, it is assumed that the ISC valve 10 is once fully closed by the calibration process. First, the central processing unit 193 of the control device 6 takes in the detection results from the various sensors 2, 3, 4, and 5, and holds them (step 50). Then, the above steps 30 to 34
The signal line is diagnosed by the same processing as in (Steps 51 and 5).
2). In this example, for simplification of the description, the abnormality is determined immediately upon detecting the abnormality. of course,
The normality determination and the abnormality determination may be performed based on a plurality of detection results as shown in FIG.

When the normality is determined, the control device 6
It is checked whether or not the calibration process has been performed (step 53). If the calibration process has been performed, a normal pattern is output (step 58), and the process ends.

If the calibration process has not been performed in step 53, it is determined whether the operating state is suitable for performing the calibration process. That is, first, it is determined whether or not the vehicle is in a deceleration state (step 54), and if not, it is further determined whether or not the engine is in a high load operation state (step 55). If it is either the deceleration state or the high-load operation state, a calibration process is performed (step 56), and the normal pattern is output, and the process ends. If neither the deceleration state nor the high load operation state is present, an abnormal time pattern is output and the processing is terminated.

Here, it is determined whether or not the vehicle is in the deceleration state, for example, only when the throttle opening detected in step 50 indicates full closure and the engine speed is a value larger than a predetermined value. It is determined that the vehicle is in a deceleration state. In addition, in the determination as to whether the engine is in the high load operation state, for example, if the throttle opening is equal to or higher than a predetermined value, the intake pipe pressure is equal to or higher than a predetermined value, and the rotation speed is higher than the predetermined value, It is determined that the vehicle is in the load operation state.

In the calibration process for the stepping motor type valve, since the valve is once fully opened or fully closed, if it is performed during operation, the rotation speed is reduced or increased, and the driver of the vehicle feels uncomfortable. give. In this example, ISC
By performing the calibration process on the valve 10 only in the deceleration state or the high-load operation state, it is possible to reduce a sense of incongruity that the calibration process gives to the driver.

Here, a specific example of the calibration process will be described. FIG. 8 shows an example in which calibration is performed by bringing the valve into the fully closed state. In the figure, STEPd is the number of drive steps (variable) of the stepping motor recognized by the control device 6, STD
EPm is the number of drive steps corresponding to the actual opening of the valve. As time passes, STEPd and STEPm
There is a gap between them. The calibration process is performed to eliminate this deviation. In FIG. 8, while the signal line is abnormal, the driving of the stepping motor is stopped, and the control device
Holds the value of Pd. At time (a), the calibration process (FIG. 7)
When step 56) is started, the control device firstly
Without driving, the maximum value STEPmax of the number of steps is set in the variable STEPd. Then, the stepping motor is driven so that the variable STEPd becomes a predetermined value smaller than 0. As a result, the valve is fully closed at time (b), and is further urged in the closing direction until time (c). Then, the control device sets 0 to the variable STEPd at the time (c). As a result, the calibration process is completed, and STEPd and STEPm are surely matched. In the case of a valve that is fully opened or fully closed by a spring mechanism when not energized, instead of the above control, simply energizing is stopped for the time required for the valve to be fully opened or fully closed autonomously. , Calibration can be performed.

As described above, during the period in which the abnormality of the signal line is detected, a large deviation occurs between the state of the valve recognized by the control device 6 and the actual opening of the valve. Therefore, the control parameter learning process is not performed during the period in which the abnormal pattern is output. This is because, in the process of FIG. 7, a step of prohibiting learning is added immediately after the process of outputting the abnormal pattern (step 57), and immediately after the process of outputting the normal pattern (step 58), This is realized by adding a step of permitting learning. Accordingly, it is possible to prevent the control parameter from being corrected to an abnormal value and the operating state from becoming abnormal. As the air-based learning process, for example, a method described in JP-A-53-44431 or JP-A-63-71541 can be used. Further, as the learning process of the fuel system, for example, JP-A-60-90944 and JP-A-61-19
No. 0142 can be used.

Even when the control device is provided with a diagnosis function for the intake system, the exhaust system, and the evaporative purge system, the diagnosis is stopped during the period when the abnormal pattern is output.
This is because, in the processing of FIG. 7, a step of prohibiting the diagnosis is added immediately after the processing of outputting the abnormal pattern (step 57), and further, immediately after the processing of outputting the normal pattern (step 58), This is realized by adding a step of permitting diagnosis. Thereby, erroneous diagnosis can be prevented. For the intake system diagnosis, for example, the method described in JP-A-1-208549, and for the exhaust system diagnosis, for example, the method described in JP-A-63-90653 is mainly used to diagnose the exhaust gas recirculation device.
Regarding the evaporative purge system diagnosis, see, for example,
Each of the methods described in JP-A-69-69 can be used.

[0047]

According to the present invention, it is possible to prevent the air flow regulating valve from performing an unintended operation due to a signal line abnormality of the stepping motor, and to return to normal control autonomously when the signal line abnormality is restored. Thus, it is possible to provide a control device for an internal combustion engine that enables this.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a system according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a configuration of a control device.

FIG. 3 is a diagram showing a normal pattern (a) and an abnormal pattern (b).

FIG. 4 is a sectional view showing an example of a stepping motor type valve.

FIG. 5 is a diagram showing a relationship between a duty ratio of an energizing time of a stepping motor and a coil temperature.

FIG. 6 is a diagram illustrating an example of a stepping motor driving process of a control device.

FIG. 7 is a diagram showing another example of the stepping motor driving process of the control device.

FIG. 8 is an explanatory diagram of a calibration process for a stepping motor type valve.

FIG. 9 is a diagram showing a relationship between an energization pattern of a stepping motor and an opening / closing direction of a valve.

FIG. 10 shows a stepping motor 2 in a conventional apparatus.
It is a figure showing an example of operation at the time of phase break.

FIG. 11 is a diagram illustrating an example of a drive monitor circuit (for one phase) of a stepping motor.

FIG. 12 is a diagram showing a relationship between a drive signal and a monitor signal in a conventional device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 1d ... Intake pipe, 1e ... Exhaust pipe, 2 ... Rotation speed sensor, 3 ... Cooling water temperature sensor, 4 ... Intake pipe pressure sensor, 5 ... Throttle opening degree sensor, 6 ... Control device for internal combustion engine, 7 ... Air-fuel ratio sensor, 8 ... Fuel injection valve, 9 ... Spark plug, 10 ... Stepping motor type ISC valve, 11 ...
Fuel tank, 12 ... Charcoal canister, 13 ... Stepping motor type CP valve, 14 ... Stepping motor type EGR valve, 191 ... Input circuit, 192 ... A / D
Conversion unit, 193 Central processing unit, 194 ROM, 195
... RAM, 196, output circuit, 197, drive circuit.

Claims (10)

[Claims] An internal combustion engine connected to a plurality of gas flow control valves for an intake system or an exhaust system of an internal combustion engine using a stepping motor driven by a plurality of excitation signals to control an operation state of the internal combustion engine. In the engine control device, a driving unit for supplying an excitation signal to the stepping motor, and a signal line diagnostic unit for detecting the presence or absence of an abnormality in a signal line transmitting the excitation signal based on a state of the excitation signal. And control means for controlling the degree of opening of the gas flow control valve by controlling the drive means, wherein at least the signal line diagnostic means detects an abnormality in the signal line. In the period, the driving unit is controlled such that all of the excitation signals supplied to the stepping motor of the target gas flow control valve are in phase with each other. Control unit for fuel engine. 2. The control device for an internal combustion engine according to claim 1, wherein the gas flow control valve includes a valve having a mechanism for fully opening or completely closing the valve during a period when no excitation signal is supplied to the stepping motor. The control means, after the signal line diagnostic means has detected an abnormality in the signal line, at least only during the time required for the gas flow rate adjustment valve to autonomously fully open or fully closed, the excitation signal of the drive means A control device for an internal combustion engine, wherein the supply is stopped. 3. The control device for an internal combustion engine according to claim 1, wherein the excitation signal is a pulse signal including an energizing period and a non-energizing period, and is supplied during a period in which abnormality of the signal line is detected. The excitation signal has a pulse width and a period determined in advance so that the heat generation amount of the stepping motor does not exceed an allowable range even when the excitation signal is continuously supplied. Control device for internal combustion engine. 4. The control device for an internal combustion engine according to claim 3, wherein the signal line diagnostic means detects whether or not there is an abnormality in both the energizing period and the non-energizing period of the pulse signal. The excitation signal supplied during the period in which the pulse signal is detected further secures the time required for the signal line diagnostic means to perform normal and abnormal detection in both the energizing period and the non-energizing period of the pulse signal. A control device for an internal combustion engine characterized in that the pulse width and the cycle are predetermined. 5. The control device for an internal combustion engine according to claim 1, further comprising an operating state detecting means for detecting an operating state of the internal combustion engine, wherein the control means further opens the gas flow control valve once or completely. A calibration process of calibrating the opening degree of the valve by fully closing the internal combustion engine is performed by the operation state detection unit after the abnormal state of the signal line is detected by the signal line diagnosis unit. A control device for an internal combustion engine, which is executed when a state becomes a predetermined operation state. 6. The control device for an internal combustion engine according to claim 5, wherein said control means keeps executing said calibration processing even after said signal line diagnostic means detects that said signal line is normal. So that the excitation signal at the time of signal line abnormality is supplied,
A control device for an internal combustion engine, which controls the driving means. 7. The control device for an internal combustion engine according to claim 5, wherein the gas flow rate adjusting valve includes an idle speed control valve which is once fully closed in the calibration process. The control for the internal combustion engine, wherein the predetermined operation state in the control valve calibration process is any one of a state in which the vehicle equipped with the internal combustion engine is in a deceleration state and a state in which the vehicle is under a high load operation state. apparatus. 8. The control device for an internal combustion engine according to claim 1, further comprising an operating state detecting means for detecting an operating state of the internal combustion engine, wherein the control means further comprises a control parameter used for controlling the internal combustion engine. Learning processing for correcting the excitation value supplied to the stepping motor to an appropriate value based on the detection result of the operating state detection means is performed only during a period when all of the excitation signals supplied to the stepping motor are not in-phase signals. Control device for an internal combustion engine. 9. The control device for an internal combustion engine according to claim 1, wherein a diagnosis means for diagnosing at least one of an intake system, an exhaust system, and an evaporative purge system of the internal combustion engine is provided.
The control device for an internal combustion engine, wherein the diagnosis unit does not perform the diagnosis during a period in which all of the excitation signals supplied to the stepping motor are in-phase. 10. A method of driving a gas flow control valve for an intake system or an exhaust system of an internal combustion engine using a stepping motor driven by a plurality of excitation signals, the method comprising: detecting an abnormality in a signal line transmitting the excitation signal. The presence / absence is detected in a state where the excitation signal is changing, and at least during a period in which an abnormality is detected, all of the excitation signals supplied to the stepping motor are in-phase signals. How to drive the gas flow control valve.