JPH11190230A - Engine throttle valve control device and control method - Google Patents

Abstract

(57) [Summary] (Corrected) [PROBLEMS] A throttle valve control device and control method capable of diagnosing abnormality of a throttle valve return mechanism by specifying that a return spring is not a failure but an electrical failure. I will provide a. A throttle valve is controlled by an electrical control means to open the throttle valve to a predetermined diagnostic opening degree in an engine stopped state, and when opened, the electrical control by the electrical control means is stopped to mechanically return the throttle valve. Monitor the status.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine intake air amount control apparatus for adjusting the output of an engine of an automobile or the like, and more particularly to an engine throttle valve control apparatus and control method.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. 8-277728 discloses an electric control device for a throttle valve which is disposed in a pipeline for introducing air into an engine and controls opening and closing of a throttle valve for adjusting an amount of intake air to the engine by a motor. In stopping the engine, the throttle valve driven and controlled to the fully closed position by the motor is opened from the fully closed position by a predetermined opening in the opening direction independently of the electric control by the motor. There is described an electric control device for a throttle valve, which is provided with a forced valve opening mechanism that is forcibly opened by force.

Further, Japanese Patent Publication No. 5-55695 discloses that
In an apparatus for controlling the position of a throttle valve in an intake pipe of an internal combustion engine, a throttle valve 35 connected to an electric operation device 34 and a throttle valve via the electric operation device according to the position of an accelerator pedal during running operation. An electronic control unit 11 for controlling the electronic control unit to a predetermined position, a means for supplying a power supply voltage to the electronic control unit during running operation, an ignition switch opened when the internal combustion engine is stopped, and an internal combustion engine when the ignition switch is opened. A time signal generator for maintaining the voltage supply to the electronic control device when stopped for a predetermined time and cutting off the voltage supply after the elapse of the time, wherein the electronic control device performs the electrical operation device during the predetermined time Via the intake valve of the internal combustion engine, wherein the throttle valve is first controlled to a closed position for a predetermined time, and then the throttle valve is controlled again to an open position. Definitive throttle valve position control device is described.

[0004]

As described above, there has been known a throttle valve return mechanism in which a forcible valve opening mechanism is provided by an elastic force of an elastic body and forcibly opened independently of electric control by a motor.

A return spring diagnosis for the return spring disconnection for such a throttle valve return mechanism is required, a throttle shaft for the throttle valve predetermined opening holding mechanism, and a throttle opening for the motor fixed.
There is a need for a default mechanism diagnosis for default spring disconnection or default mechanism failure.

A failure mode such as breakage of the return spring can be said to be a failure mode in which the control by the motor must not be stopped because the throttle valve is required to close by itself. The problem with current control is that it is not possible to identify return spring anomalies. Therefore, the present invention provides an engine which can identify and diagnose a return spring failure, not an electrical failure, to warn a driver of the occurrence of a failure before danger and prompt repair. It is an object to provide a throttle valve control device and a control method.

Another object of the present invention is to improve the safety by performing a reliable diagnosis of the throttle valve return mechanism and the throttle valve predetermined opening holding mechanism, and to perform a fail-safe process.

[0008]

SUMMARY OF THE INVENTION The present invention is characterized in that a defect of a return spring is specified. For this reason, the throttle valve is controlled by an actuator to a predetermined diagnostic opening while the engine is stopped, and the throttle valve is opened. Stop the electric control (motor control) by the actuator,
By monitoring the return state of the throttle valve, a defect of the return spring is determined. At the same time, by monitoring the return state, it is discriminated whether the malfunction of the throttle valve return mechanism or the malfunction of the throttle valve predetermined opening maintaining mechanism. Another object of the present invention is to provide a method for diagnosing various throttle valve return mechanisms, and to appropriately combine them.

The present invention specifically provides the following apparatus and method.

Means for electrically controlling the throttle valve opening for adjusting the intake air of the engine; a throttle valve return mechanism for mechanically closing the throttle valve to a predetermined opening; A throttle valve control device provided with a throttle valve predetermined opening holding mechanism for holding the opening at an opening degree, wherein the electronic control means controls the throttle valve to a predetermined opening for diagnosis in an engine stopped state and opens the throttle valve in an open state; And stopping the electric control by the electric control means, monitoring the return state of the throttle valve by the throttle valve return mechanism, and diagnosing a failure of the throttle valve return mechanism. Engine throttle valve controller.

The return state of the throttle valve is determined by the first state.
And a throttle valve control device for an engine which determines whether or not the valve moves to the closing side within a predetermined opening time with respect to a predetermined opening degree.

The engine is characterized in that the return state of the throttle valve to the opening is mechanically returned to the predetermined opening within a predetermined time, and whether the throttle valve is maintained at the predetermined opening is determined. Throttle valve controller.

Means for electrically controlling the throttle valve opening for adjusting the intake air of the engine; a throttle valve return mechanism for mechanically closing the throttle valve to a predetermined opening; A throttle valve control device provided with a throttle valve predetermined opening holding mechanism for holding the opening at an opening degree, wherein the electronic control means controls the throttle valve to a predetermined opening for diagnosis in an engine stopped state and opens the throttle valve in an open state; The electric control by the electric control means is stopped, and the return state of the throttle valve is monitored by the throttle valve return mechanism, and the failure of the throttle valve return mechanism and the failure of the throttle valve predetermined opening holding mechanism are separated. A throttle valve control device for an engine, which performs diagnosis.

An intake air amount valve control device for an engine, wherein an opening degree of a throttle valve is measured using a throttle sensor.

Means for electrically controlling the throttle valve opening for adjusting the intake air of the engine; a throttle valve return mechanism for mechanically closing the throttle valve to a predetermined opening; A throttle valve control device provided with a predetermined opening degree holding mechanism for holding a throttle valve, a command value such as a current command value to the electric control means and a motor drive DUTY command value when the throttle valve return mechanism fails, and a normal value. A command value between the current command value to the electric control means at the time and a command value such as a motor drive DUTY command value, and the command value to the electric control means is stored in the stored command value. A throttle valve control device for an engine, further comprising: a throttle valve return mechanism failure diagnosis device for determining whether the throttle valve return mechanism has failed by determining whether the throttle valve return mechanism has failed.

Means for electrically controlling the throttle valve opening for adjusting the intake air of the engine; a throttle valve return mechanism for mechanically closing the throttle valve to a predetermined opening; A throttle valve control device having a predetermined opening degree holding mechanism for holding the throttle valve, a current consumption value to the electrical control means when the throttle valve return mechanism of the electrical control means fails, and a normal electrical control means Having a device for storing a current consumption value between the current consumption value and a means for measuring the current consumption value of the electric control means, wherein the current consumption value of the electric control means is stored. A throttle valve control device for an engine, further comprising: a throttle valve return mechanism failure diagnosis device for determining whether the throttle valve return mechanism has failed by determining whether the throttle valve return mechanism has failed.

Means for electrically controlling the throttle valve opening for adjusting the intake air of the engine; a throttle valve return mechanism for mechanically closing the throttle valve to a predetermined opening; In the throttle valve control device provided with the throttle valve predetermined opening holding mechanism, the switching frequency between the throttle valve control direction when the throttle valve return mechanism fails and the switching frequency in the normal throttle valve control direction when the throttle valve return mechanism fails. A device for storing a frequency, and determining whether or not the switching frequency of the control direction of the throttle valve during the normal control is greater than the switching frequency of the stored control direction. A throttle valve control device for an engine, comprising a throttle valve return mechanism failure diagnosis device for diagnosis.

Means for electrically controlling the throttle valve opening for adjusting the intake air of the engine, a throttle valve return mechanism for mechanically closing the throttle valve for a predetermined period of time, and mechanically opening the throttle valve to a predetermined opening to obtain a predetermined throttle valve opening A throttle valve control device provided with a mechanism for holding a predetermined opening degree of the throttle valve, wherein the electronic control means controls the throttle valve to a first predetermined opening degree and opens the throttle valve. Is stopped, the throttle valve returns to the second predetermined opening degree by the throttle valve return mechanism,
A throttle valve predetermined opening degree holding mechanism failure diagnosis device for mechanically monitoring a state held near the second predetermined opening degree to diagnose a failure of the throttle valve predetermined opening degree holding mechanism; Characteristic engine throttle valve control device.

The opening degree of the throttle valve for adjusting the intake air of the engine is electrically controlled, and when the electric control is stopped, the opening degree is mechanically closed to a predetermined opening degree, and the valve is mechanically opened to a predetermined opening degree. In the throttle valve control method for opening and maintaining a predetermined opening degree, when the engine key is ON (when the engine is ON), a command value or a duty (DUTY) to the electric control means during normal control is stored in advance. When the key of the engine is OFF (during engine stop)
The throttle valve is opened by the electrical control means, the control of the electrical control means is stopped, and the mechanical return state of the throttle valve is monitored to diagnose the failure of the throttle valve return mechanism. A throttle valve control method for an engine.

[0020]

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

FIG. 1 shows an example of an engine system to which the present invention is applied. In the drawing, air to be taken in by an engine 1 is taken in from an inlet 4 of an air cleaner 3 and enters a collector 8 through a throttle valve device 7 provided with a throttle valve 6 for controlling the amount of intake air. The throttle valve 6 is
The throttle valve 6 is connected to the motor 10, and the throttle valve 6 is operated by driving the motor 10. By operating the throttle valve 6,
The intake air volume is controlled. The intake air reaching the collector 8 is distributed to each intake air pipe 19 connected to each cylinder 2 of the engine 1 and guided to the cylinder 2.

On the other hand, fuel such as gasoline is sucked and pressurized from a fuel tank 11 by a fuel pump 12, and then supplied to a fuel system 21 in which a fuel injection valve 13 and a variable fuel pressure regulator 14 are piped. The fuel system is adjusted to a predetermined pressure by the above-described fuel pressure regulator 14, and is moved from the fuel injection valve 13, which opens the fuel injection port of each cylinder 2, to the cylinder 2.
Injected to. Further, a signal representing the intake flow rate is output from the air flow meter 5 and input to the control unit 15.

Further, the throttle valve device 7 is provided with a throttle sensor 18 for detecting the degree of opening of the throttle valve 6, and the output thereof is also input to the control unit 15.

Reference numeral 16 denotes a crank angle sensor which is driven to rotate by a camshaft 27 and outputs a signal indicating the rotational position of the crankshaft. This signal is also input to the control unit 15.

Reference numeral 20 denotes an A / F provided in the exhaust pipe 28.
An (air-fuel ratio) sensor detects and outputs the actual operating air-fuel ratio from the exhaust gas component, and the signal is input to the control unit 15 in the same manner.

Reference numeral 9 denotes an accelerator sensor provided integrally with the throttle valve device 7, which is connected to an accelerator pedal 49. The accelerator sensor 49 detects and outputs the amount by which the driver operates the accelerator pedal 49, and outputs the signal to the control unit 15. Is input to

The control unit 15 has a storage device 25 and processing means 26, and receives as input signals signals from various sensors for detecting the operating state of the engine, such as the aforementioned crank angle signal and accelerator opening signal. The fuel injection valve 1 performs a predetermined calculation and outputs various control signals calculated as a result of the calculation.
A predetermined control signal is output to the motor 3, the ignition coil 17, and the motor 10 for operating the throttle valve to execute fuel supply control, ignition timing control, and intake air amount control.

A motor driver relay 31, a control unit relay 32, and an ignition switch 33 are provided between the power supply (battery) 30 and the control unit 15.

Reference numeral 35 denotes a warning device.

Since these structures are well known, no further explanation is required.

FIG. 2 schematically shows a throttle valve control device. The throttle valve 6 is fixed to a throttle valve shaft 40 and is rotatably held by a throttle body main body (not shown). Throttle valve 40
A driving member 41 is connected to the driving member 41.
The throttle valve 6 is driven to open and close by the motor actuator 42. The drive control signal of the actuator 42 is
Provided from the control unit 15. Further, an engagement member 43 composed of a metal thin plate lever that is engaged when the drive member 41 rotates in the throttle valve closing direction is disposed, and the engagement member 43 and the drive member are provided between these members. A return spring 44 for applying a biasing force in a direction for rotating the first and second members 41 in opposite directions is stretched. A default spring 45 is provided between the engagement member 43 and the throttle body main body to apply a biasing force to rotate the throttle valve 6 in the opening direction. Further, a fully closed stopper 4 for defining a fully closed position of the throttle valve 6 is provided on the throttle body.
6, a fully-open stopper 52 for defining a fully-open position of the throttle valve 6,
A default stopper 47 that defines the position of the throttle valve 6 when the drive control signal of the actuator 42 stops is provided. The position of the driving member 41 is detected by the throttle valve sensor 48 and input to the control unit 15.

In this configuration, during normal operation, the throttle valve 6 and the driving member 41 are opened and closed by the actuator 42 between the position of the fully closed stopper 46 and the position of the fully opened stopper 52. When the engine is stopped, the throttle valve 6 is open from the fully closed position (default state).
It is possible to improve the restartability of the engine and prevent sticking of the throttle valve.

The movement of the accelerator pedal 49 is transmitted to the limp home link 50.

An accelerator return spring 51 is provided between the throttle body main body and the link member 50. In this state, the position of the link member 50 is detected by the accelerator sensor 9 and input to the control unit 15.

Regarding a method of determining an abnormality of the throttle valve return mechanism,
This will be described with reference to the flowcharts of FIGS. 3, 4 and 5 and the time chart of FIG.

An accelerator sensor signal is read based on throttle valve control (step 100), a throttle sensor signal is read (step 101), an accelerator opening is calculated (step 102), and a throttle valve opening is calculated (step 103). Normal throttle valve target opening calculation (step 10)
Perform 4). It is determined whether or not the motor control is permitted (step 105). If NO, the process jumps to step 116 described later. If YES, it is determined whether an abnormality is determined based on the throttle valve return mechanism diagnosis or the predetermined throttle opening mechanism diagnosis. When it is determined (step 106) that the abnormality is determined (YES), the target throttle opening for feedback control is fixed to the throttle valve target opening at the time of abnormality determination in step 111.

In the case of NO, it is determined whether the diagnostic condition is satisfied (step 107). In the case of NO, the target throttle valve opening for feedback control is set to the normal throttle valve target opening (step 109). . The process proceeds from step 111 or step 109 to step 114 described later. Y
In the case of ES, the target throttle valve opening for feedback control is set to the target throttle valve opening for diagnosis (step 108).
Diagnosis of the throttle valve return mechanism (step 112) is performed from this state, and diagnosis of the predetermined opening degree maintaining mechanism of the throttle valve (step 113).
I do. When the diagnosis is completed, a feedback control constant is determined (step 114), and a throttle feedback control (step 115) is performed to generate a motor drive output (step 116).

FIG. 4 is a flowchart for diagnosing the throttle valve returning mechanism. The diagnostic throttle valve target opening calculation (step 120) is performed, and is the throttle valve opening closed to a predetermined opening or less? Is determined, the process is terminated if NO, and if YES, the drive output of the actuator is set to 0, that is, the motor control is turned OFF. Did this close the throttle valve opening below the predetermined opening? Is determined (step 123). If yes, end; if no, has a certain time elapsed? Is determined (step 124). If the determination is NO, the process ends. If the determination is YES, a determination is made as to whether the throttle valve return mechanism is abnormal (step 125).

FIG. 5 is a flowchart for diagnosing the mechanism for maintaining the predetermined opening of the throttle valve. Has the throttle valve mechanism diagnosis described above been completed? Is determined (step 130). If NO, the process ends. If YES, has a certain time elapsed? Is determined (step 131). If NO, end, Y
In the case of ES, is the throttle valve opening within the predetermined opening range? Is determined. If yes, has it ended, and if no, has a certain time elapsed? Is determined (step 133). If the determination is NO, the process ends. If the determination is YES, it is determined that the throttle valve predetermined opening degree maintaining mechanism is abnormal (step 134).

FIG. 6 is a time chart showing these flowcharts. Ignition switch (SW) OFF, engine stopped, throttle valve return mechanism diagnosis started, motor control state switched from normal motor control to motor control under diagnosis, feedback control throttle target opening for normal throttle target opening for diagnosis Motor control stop control is performed with the throttle target opening. In this state, if the throttle valve is fixed and exhibits the behavior shown in line A, if the throttle opening is maintained, it can be determined that the throttle valve return mechanism, that is, the return spring has failed.

When the throttle valve return mechanism and the throttle valve predetermined opening maintaining mechanism are normal, the throttle valve is closed to the predetermined opening as shown in FIG. This is not a fully closed state, but a state in which a fixed opening is set for the restart as described above.

When the opening of the throttle valve is not the predetermined opening of the throttle valve,
If the behavior shown by the line B or C is exhibited, it can be determined that there is a defect in the throttle valve predetermined opening maintaining mechanism, that is, the default spring or the like.

FIG. 7 is a diagram for judging the abnormality of the throttle valve return mechanism when the engine key is turned on, that is, when the ignition key is turned on. The relationship between the current command value and the throttle valve opening or the motor load torque and the throttle valve opening are determined. The abnormality of the throttle valve return mechanism is determined by observing the opening degree. When the throttle valve return mechanism is normal, the behavior of the throttle valve return mechanism shown in FIG. If there is an abnormality in the throttle valve return mechanism, the current command value takes a value lower than the abnormality determination value when the throttle return mechanism is abnormal. This means that the current command value to the electric control means when the throttle valve return mechanism fails,
A device 25 for storing a command value between a command value such as a motor drive duty command value and a command value such as a current command value to the electric control means and a motor drive duty command value in a normal state; This means that it has been determined whether or not the command value to the means is lower than the stored command value.

The abnormality of the throttle valve return mechanism can be determined based on the relationship between the motor load torque and the throttle valve opening. When the throttle valve return mechanism is normal, as shown in the figure, the motor load torque changes depending on the throttle valve opening degree on the open side and on the closed side, however, when the throttle valve return mechanism is abnormal, The behavior becomes a constant linear shape and does not change according to the throttle valve opening. This means that the device stores the current consumption value between the current consumption value of the electric control means when the throttle valve return mechanism of the electric control means fails and the current consumption value of the electric control means in the normal state. 25 comprising means for measuring the current consumption value of the electric control means, and determining whether the current consumption value of the electric control means is lower than the stored current consumption value. .

FIG. 8 is a flowchart for judging abnormality of the throttle valve return mechanism of the throttle valve return mechanism 2.

Has the diagnosis start condition been satisfied? Is determined (step 140). If NO, the process ends. If YES, is the current command value equal to or less than the abnormality determination value? Is determined (step 141). If NO, is it terminated, and if YES, has a certain time elapsed? Is determined (step 142).
If the determination is NO, the process ends. If the determination is YES, an abnormality determination of the throttle valve return mechanism is performed (step 143).

FIG. 9 is a time chart for judging abnormality of the throttle valve return mechanism based on the switching frequency of the throttle valve control direction when the throttle valve return mechanism fails. The time chart shows the relationship between the throttle valve control direction, the throttle valve opening, the diagnosis counter, and time. In the abnormality determination state of the throttle valve return mechanism, in a normal state, the throttle valve opening degree is linear as shown in the figure, but in an abnormal state, the throttle valve control direction is repeatedly inverted, and the throttle valve opening degree is a sine curve. Are superimposed. The reversal of the control direction is counted by a diagnostic counter. When the frequency is low, the count value is down-counted in a normal state to prevent erroneous diagnosis. When this count value is within a certain value, it is determined as normal, and when it exceeds a certain value, it is determined as abnormal. This means that the device 25 for storing the switching frequency between the switching frequency of the throttle valve control direction at the time of failure of the throttle valve return mechanism and the switching frequency of the throttle valve control direction at the time of normal operation is provided. It is determined whether the switching frequency of the control direction of the valve is higher than the switching frequency of the stored control direction.

FIG. 10 is a flowchart showing a method of diagnosing the throttle valve return mechanism 3.

Have the diagnosis start conditions been satisfied? Is determined (step 150). If NO, the process ends. If YES, is the throttle control direction switched? Is determined (step 151). If NO, the judgment value is subtracted from the diagnostic counter (step 153). If YES, a predetermined value is added to the diagnostic counter (step 152). Next, is the diagnostic counter equal to or greater than the predetermined value? Is determined (step 154).
If the determination is NO, the process ends. If the determination is YES, an abnormality determination of the throttle valve return mechanism is performed (step 155).

As described above, the throttle valve return mechanisms 1, 2, 3
Has been described, but these can be used in an appropriate combination. That is, when the engine key is ON (engine O
N), the difference between the command value to the electric control means during normal control or a previously stored command value of the duty (DUTY), and when the key of the engine is OFF (during engine stop), the electric control means By opening the throttle valve, the control of the electrical control means is stopped, and the mechanical return state of the throttle valve is monitored to diagnose the failure of the throttle valve return mechanism.

In this way, the diagnosis can be performed both when the key is turned on and when the key is turned off.

Next, the fail-safe processing will be briefly described.

When the throttle valve return mechanism is diagnosed as abnormal, the following processing is performed.

(1) Warning light is turned on. (2) Close-side duty equivalent to a return spring is output.

[0055]

According to the present invention, the abnormality of the return spring can be specified by the abnormality diagnosis of the throttle valve return mechanism, and the driver can be warned of the occurrence of a failure before danger.

Further, according to the present invention, it is possible to diagnose the abnormality of the throttle valve return mechanism and the abnormality of the throttle valve predetermined opening maintaining mechanism separately.

According to the present invention, the key of the engine is turned on.
Since the diagnosis can be made in both cases of OFF and OFF, safety can be further improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of an engine system to which the present invention is applied.

FIG. 2 is a conceptual diagram of a throttle valve control device to which the present invention is applied.

FIG. 3 is a flowchart showing a control procedure of throttle valve control means to which the present invention is applied.

FIG. 4 is a flowchart of the monitoring means of the throttle valve return mechanism of the present invention.

FIG. 5 is a flowchart of the monitoring means of the throttle valve predetermined opening maintaining mechanism of the present invention.

FIG. 6 is a timing chart of monitoring means of the throttle valve return mechanism and the throttle valve predetermined opening maintaining mechanism of the present invention.

FIG. 7 is a diagram showing characteristics of the throttle valve control device when the throttle valve return mechanism is normal and when it is abnormal.

FIG. 8 is a flowchart of monitoring means of the throttle valve return mechanism of the present invention.

FIG. 9 is a timing chart of the monitoring means of the throttle valve return mechanism of the present invention.

FIG. 10 is a flowchart of monitoring means of the throttle valve return mechanism of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 5 ... Air flow meter, 6 ... Throttle valve, 7 ... Throttle device, 9 ... Accelerator sensor, 10 ... Motor, 12 ... Accelerator pedal, 15 ... Control unit, 20 ... A /
F sensor, 26 ... processing means, 36 motor driver, 40
... throttle valve shaft, 41 ... driving member, 42 ... motor actuator, 43 ... engagement member, 44 ... return spring, 45
... default spring, 46 ... metal stopper, 47 ...
Fully open stopper, 48 ... throttle valve sensor, 50 ... link for limp home, 51 ... accelerator spring.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshihiko Akagi 2477 Takaba, Hitachinaka-shi, Ibaraki Pref. Hitachi Car Engineering Co., Ltd.

Claims (10)

[Claims] A throttle valve opening mechanism for controlling intake air of an engine; a throttle valve return mechanism for mechanically closing the throttle valve to a predetermined opening; and a throttle valve for mechanically opening the throttle valve to a predetermined opening. A throttle valve control device provided with a throttle valve predetermined opening holding mechanism for holding the throttle valve at a predetermined opening. A throttle valve return mechanism failure diagnosing device that stops the electrical control by the electrical control means in the retracted state, monitors the return state of the throttle valve by the throttle valve return mechanism, and diagnoses a failure of the throttle valve return mechanism. An throttle valve control device for an engine, wherein the throttle valve control device is provided. 2. The method according to claim 1, wherein the return state of the throttle valve is determined based on whether or not the throttle valve moves to the closing side within a predetermined opening degree with respect to the first predetermined opening degree and within a predetermined time. Engine throttle valve controller. 3. The method according to claim 1, wherein the return state of the throttle valve to the opening degree is mechanically returned to the predetermined opening degree within a predetermined time, and is determined based on whether the opening degree is maintained at the predetermined opening degree. Characteristic engine throttle valve control device. A throttle valve opening mechanism for controlling intake air of the engine, a throttle valve return mechanism for mechanically closing the throttle valve to a predetermined opening, and a mechanically predetermined opening. A throttle valve control device for opening the throttle valve to a predetermined opening degree, and holding the throttle valve at a predetermined opening degree. Then, the electric control by the electric control means is stopped in the opened state, the return state of the throttle valve is monitored by the throttle valve return mechanism, and the failure of the throttle valve return mechanism and the throttle valve predetermined opening degree are monitored. An engine throttle valve control device characterized in that a failure of a holding mechanism is classified and diagnosed. 5. An intake air amount valve control device for an engine according to claim 1, wherein the degree of opening of the throttle valve is measured by using a throttle sensor. 6. A means for electrically controlling a throttle valve opening for adjusting intake air of an engine, a throttle valve return mechanism for mechanically closing the throttle valve to a predetermined opening, and a throttle valve for mechanically opening the throttle valve to a predetermined opening. A throttle valve control device having a predetermined opening degree maintaining mechanism and a predetermined opening degree maintaining mechanism, wherein a command value such as a current command value to an electric control unit or a motor drive duty command value when the throttle valve return mechanism fails. And the current command value to the electric control means in the normal state, the motor drive DUTY
A device for storing a command value between command values such as a command value, and determining whether or not the command value to the electric control means is lower than the stored command value; A throttle valve control device for an engine, comprising a throttle valve return mechanism failure diagnosis device for diagnosing a failure of a return mechanism. 7. A means for electrically controlling a throttle valve opening for adjusting intake air of an engine, a throttle valve return mechanism for mechanically closing the throttle valve to a predetermined opening, and a throttle valve for mechanically opening the throttle valve to a predetermined opening. A throttle valve for holding a predetermined opening degree, a throttle valve control apparatus having a predetermined opening degree holding mechanism, wherein a current consumption value to the electrical control means when the throttle valve return mechanism of the electrical control means fails and an electric A device for storing a current consumption value between the current consumption value to the control means; and a means for measuring the current consumption value of the electric control means, wherein the current consumption value of the electric control means is stored. A throttle valve control device for an engine, further comprising: a throttle valve return mechanism failure diagnosis device for determining whether the throttle valve return mechanism has failed by determining whether the current consumption value has decreased. 8. A means for electrically controlling a throttle valve opening for adjusting intake air of an engine, a throttle valve return mechanism for mechanically closing the throttle valve to a predetermined opening, and a throttle valve for mechanically opening the throttle valve to a predetermined opening. A throttle valve control device provided with a throttle valve holding mechanism for holding a predetermined opening degree, wherein the switching frequency of the throttle valve control direction when the throttle valve return mechanism fails and the switching frequency of the throttle valve control direction when normal And determining whether the switching frequency of the control direction of the throttle valve at the time of the normal control is higher than the switching frequency of the stored control direction. A throttle valve control device for an engine, comprising a throttle valve return mechanism failure diagnosis device for diagnosing a fall. 9. A means for electrically controlling the throttle valve opening for adjusting the intake air of the engine, a throttle valve return mechanism for mechanically closing the throttle valve for a predetermined time, and a mechanism for mechanically opening the throttle valve to a predetermined opening to set the throttle valve to a predetermined value. A throttle valve control device having a predetermined opening degree holding mechanism for holding the opening degree, wherein the electronic control means controls the throttle valve to a first predetermined opening degree, opens the throttle valve, and opens the throttle valve electrically. The control by the control means is stopped, and the throttle valve is returned to the second predetermined opening by the throttle valve return mechanism, and the state in which the throttle valve is mechanically held near the second predetermined opening is monitored to monitor the throttle valve. A throttle valve control device for an engine, comprising a throttle valve predetermined opening degree holding mechanism failure diagnosis device for diagnosing a failure of the predetermined opening degree holding mechanism. 10. The throttle valve for adjusting the intake air of the engine is electrically controlled, and when the electrical control is stopped, the throttle valve is mechanically closed to a predetermined opening and the valve is mechanically opened. In the throttle valve control method that opens to a predetermined degree and maintains a predetermined opening degree, when the engine key is turned on (when the engine is turned on), the command value or duty (DUTY) to the electric control means during normal control is determined in advance. When the key of the engine is turned off (while the engine is stopped), the throttle valve is opened by the electric control means, the control of the electric control means is stopped, and the mechanical control of the throttle valve is stopped. A throttle valve control method for an engine, wherein a return state of the throttle valve is monitored to diagnose a failure of the throttle valve return mechanism.