JPH05163988A - Control device for throttle valve - Google Patents

Abstract

PURPOSE:To provide a control device for a throttle valve which has strong rotor holding force at the time of stopping a step motor and excellent control responsibility. CONSTITUTION:A throttle valve control device is composed of a 1-2-phase excitation step motor to drive a throttle valve 25 and a motor control device 3 to drivingly control the step motor 2. The motor control device 3 has an excited state distinguishing means 31 to distinguish whether the excited state is 1-phase excitation or 2-phase-excitation when the throttle valve 25 attains a target opening and the step motor then stops, and a step decreasing means 32 to decrease the number of the target steps of the step motor 2 by one in the case of the 1-phase excitation. The excited state at the time of stopping the step motor is set up to be the 2-phase excitation to strengthen rotor holding force for controlling the vibration of the rotor at the time of stopping the motor, and the continuation of control at next time can therefore be hastened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throttle valve control device for controlling the opening of a throttle valve arranged in an intake system of an engine.

[0002]

2. Description of the Related Art For the operation of a throttle valve provided in a vehicle engine, there is a method of electrically detecting the operation amount of an accelerator and controlling the opening degree by a step motor according to the operation amount ( JP-A-63-150450). The accelerator operation amount is linked with the accelerator pedal depression amount. By the way, as a typical excitation method for rotationally driving the step motor,
Phase excitation, 2-phase excitation, 1-2 phase excitation can be mentioned. Among them, the 1-2 phase excitation has double the resolution as compared with the other two excitation methods, and is suitable for controlling the throttle valve.

[0003]

[Problems to be Solved] However, when the step motor is stopped from the driving state, the rotor vibrates. That is, the step motor of 1-2 phase excitation stops in both 1-phase excitation and 2-phase excitation. However, when stopped by 1-phase excitation, the holding force of the rotor is weak, so compared to the case of 2-phase excitation. Vibration is slow to be dampened. This state is shown in FIG. That is, the figure shows the damping state of the vibration after stopping the step motor, where A is the case of one-phase excitation and B is the case of
Indicates the case of two-phase excitation. From the figure, it can be seen that the vibration time after stopping is short in the case of two-phase excitation.

On the other hand, when the step motor is driven during the above-mentioned vibration, the step motor causes resonance step out. Therefore, the step motor cannot be started during the vibration. Therefore, it is not possible to shift to the next throttle valve control, and the control response is poor. In view of the above conventional problems, the present invention aims to provide a throttle valve control device that has a strong rotor holding force when the step motor is stopped and is excellent in control response.

[0005]

According to the present invention, a throttle valve for adjusting the amount of air taken into an engine, a 1-2 phase excitation step motor for driving the throttle valve, and a motor control for controlling the driving of the step motor. And a device, and
The motor control device, when the throttle valve reaches the target opening and the step motor is stopped, the excitation state determining means for determining whether the excitation state is one-phase excitation or two-phase excitation, and one-phase excitation. In this case, the throttle valve control device is provided with step reducing means for reducing the target number of steps of the step motor by one.

What is most noticeable in the present invention is to use the 1-2 phase excitation type as the step motor, and to decrease the throttle valve by one when the excitation state when the step motor is stopped is the one phase excitation. There is a means of reduction. As a result, the step motor is always stopped in the two-phase excitation state to suppress vibration. The target opening is the opening of the throttle valve required by the engine at this time. When the throttle valve reaches the target opening, the throttle valve stops. As the target opening detection means, for example, there is a magnetic throttle sensor. As the excitation state determination means, for example, there is a method of detecting the ON / OFF state of each phase of the step motor. Further, as the step reducing means, for example, there is a method of sending a drive pulse to a step motor to drive the step motor step by step.

Further, in the control device of the present invention, when the step motor is driven, when the voltage of the battery (power supply) is reduced, the torque of the step motor is reduced, and the load may be lost to cause step-out. In order to deal with such a case, it is preferable to provide a means for reducing the maximum pulse rate in anticipation of a decrease in the power supply voltage when the switch of the electric load (air conditioner, headlight, etc.) is turned on (implementation See Example 2).

Further, even by the above means, the step motor may further be out of phase and out of step. Therefore,
To cope with this, it is preferable to provide a means for switching the control method of the step motor from open loop control to feedback control and continuing the control of the throttle valve (see Embodiment 3).

[0009]

In the present invention, the step motor for opening and closing the throttle valve is driven according to the number of steps sent from the motor control device. When the throttle valve reaches the target opening, the motor controller does not send the number of steps, and the step motor stops. Therefore, the excitation state determination means determines whether the excitation state at the time of stop is one-phase excitation or two-phase excitation. If it is 2-phase excitation, the process is continued as it is. In the case of one-phase excitation, the target number of steps is decreased by one by the step reducing means, and the excitation state is set to two-phase excitation.

As a result, the rotor of the step motor is
It is strongly held by two-phase excitation and vibration is suppressed. Therefore, the control can be shifted to the next control quickly, and the responsiveness of the throttle valve control is improved. When the above operation is performed, the target number of steps is deviated by one. However, since the reduction gear is usually interposed between the step motor and the throttle valve, the one step difference of the step motor is a minute opening difference in the throttle valve and is not a problem.

As described above, when the one-phase excitation is stopped, the step number is "decreased" by one from the target step number. Therefore, as if you "increase" one,
There is no risk that the throttle valve will rotate too much and will come into contact with the fully closed or fully opened stopper, and the throttle valve will be damaged. As described above, according to the present invention, it is possible to provide a throttle valve control device having a strong rotor holding force when the step motor is stopped and an excellent control response.

[0012]

【Example】

Embodiment 1 A throttle valve control device according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, the throttle valve control device of the present embodiment is configured such that a throttle valve 25 for adjusting the amount of air taken into the engine 1 and a 1-2 phase excitation step motor 2 for driving the throttle valve 25.
And a motor control unit (ECU) 3 for driving and controlling the step motor 2. In addition, the motor control device 3
Is an excitation state determination means 31 for determining whether the excitation state is one-phase excitation or two-phase excitation when the throttle valve 25 reaches the target opening and the step motor 2 stops.
In the case of one-phase excitation, the step motor 2 has step reduction means 32 for reducing the target number of steps by one.

Further, an accelerator position detecting means 42 for detecting an accelerator operation amount is electrically connected to the motor control device 3. An accelerator pedal 41 is connected to the accelerator position detecting means 42 via a link mechanism. A throttle sensor 26 for detecting the opening degree of the throttle valve 25 is electrically connected to the motor control device 3. Further, the motor control device 3 has
ON / OFF signals for electric loads such as air conditioners and headlamps,
A signal such as the battery voltage is input.

Next, the operation and effect of the above control device will be described with reference to the flow charts of FIGS. 1 and 2. That is, first, the step motor 2 is drive-controlled (rotated) by the number of steps sent from the motor control device 3 in step (hereinafter omitted) 101 in FIG. And 102
At, it is judged whether or not the number of steps of the step motor has reached the target opening of the throttle valve, and when it has not reached it, the process returns to 101 again and drive control is continued. The opening of the throttle valve is detected by the throttle sensor 26, and its signal is sent to the motor control device 3.

Then, at 102, when the throttle valve reaches the target opening, the routine proceeds to 103, where the step number is not sent from the motor control device 3, and the step motor is stopped in that state. Next, at 104, the excitation state determination means 31 determines whether the excitation state when the step motor is stopped is one-phase excitation or two-phase excitation. If the stop is two-phase excitation, the stop excitation state of the throttle valve is continued as it is.

On the other hand, when it is judged at 104 that the excitation state is the one-phase excitation, the excitation state at the time of stop is set to the two-phase excitation.
Reduces the target number of steps by one. By the above,
Regardless of the stop excitation state, the two-phase excitation state is finally reached. Therefore, the rotor of the step motor is
Strongly held by two-phase excitation. Therefore, the vibration of the rotor when stopped is suppressed. Therefore, it is possible to immediately shift to the next throttle valve control, and the control response is excellent.

Further, although the number of steps is deviated by one by reducing the target number of steps by one, since a reduction gear is provided between the step motor 2 and the throttle valve 25, There is almost no effect on the opening of the throttle valve. Moreover, since the number of steps is reduced by one from the target number of steps, the throttle valve will not rotate too much and will not come into contact with the fully closed or fully opened stopper, which may cause damage to the throttle valve. Absent.

Second Embodiment In this embodiment, as shown in FIGS. 3 and 4, in the control device of the first embodiment, a decrease in battery voltage is predicted while the step motor is being driven, and step out of the step motor is prevented. Control device that can That is, when the voltage of the battery that drives the step motor decreases, the torque of the step motor decreases, and the step motor may lose step due to the load (load step out). When the step motor is out of step, the throttle valve is returned to the fully closed state by the return spring provided in the throttle valve, and the engine rotation is disturbed.

For this reason, conventionally, the battery voltage is monitored, and the maximum pulse rate for driving the step motor is reduced according to the situation where the battery voltage drops to prevent load step-out. However, as shown by K in Fig. 3, the use of high-current consuming equipment such as air conditioners and headlights
The battery voltage may drop sharply. In this case, the maximum pulse rate cannot follow the rapid change in voltage,
As indicated by M in the same figure, a load step-out may occur.

Therefore, in this example, a switch signal (ON / OFF signal) of a current load such as an air conditioner or a headlamp and a signal of a battery voltage are input to the motor control device 3 (FIG. 1). And these switches are ON
Then, the maximum pulse rate is reduced in anticipation of the battery voltage drop (Fig. 3). As a result, step out load of the step motor is prevented. The above-mentioned maximum pulse rate means the speed control which is usually called slow-up or slow-down in order to perform a smooth operation of the step motor, and means the fastest speed during this period.

Next, the operation and effect of this embodiment will be described with reference to FIGS.
Will be explained. First, the step motor is the first embodiment.
The drive is controlled similarly to. Then, as shown in the flowchart of FIG. 4, at 201, it is determined whether or not the load switch of the air conditioner or the like is ON. OFF
In the case of, the battery voltage is detected at 202, and
The maximum pulse rate was calculated in 03, and 20
In step 4, the step motor is driven.

On the other hand, when it is determined that the load switch is ON, the pulse rate is reduced to a preset pulse rate (for example, 40% of the maximum value), and drive control of the step motor is performed at 204. FIG. 3 shows the above control in time series, and in the present invention, the maximum pulse rate is immediately lowered at the time point P when the load switch is turned on. On the other hand, in the above-mentioned conventional technology,
The load switch is turned on (point P), and at the time (Q) after which the battery voltage starts to drop, sampling of the battery voltage is started. Then, after a certain sampling period (R), the maximum pulse rate is lowered only when the battery voltage is still lowered. Therefore, the response was slow and there was a risk of step out.

In the present invention, as described above, the ON signal of the load switch is detected, the decrease in the battery voltage is predicted, and the maximum pulse rate is decreased. Then, since the torque is increased by decreasing the maximum pulse rate, there is no risk of load loss. The load switch is O
When set to FF, the maximum pulse rate is increased to the normal state.

Embodiment 3 In this embodiment, as shown in FIGS. 5 to 8, also in Embodiments 1 and 2, when the step motor is still out of phase or out of step, the step motor control method is opened. The present invention relates to a control device capable of continuing control of a throttle valve by switching from loop control to feedback control. That is, in general, in the past, when controlling a step motor, open loop control, which controls only by a signal transmitted from a motor control device, has been adopted as normal control.

However, in the case of performing throttle valve control with a step motor, if a phase shift (shift between the number of steps of the step motor and the actual throttle valve opening) occurs, the above-mentioned open loop control can control the throttle valve to a normal state. Disappear. Therefore, it is necessary to restore the open-loop control to normal by making the number of steps caused by the phase shift correspond to the throttle valve opening. Such means is described in the above-mentioned JP-A-63-150450.

This means is to correct the control by immediately cutting the current to the step motor to stop the step motor after the occurrence of the phase shift and returning the throttle valve to the fully closed position (that is, initialization) by the return spring. Is. However, with this method, if the throttle valve is fully closed while the vehicle is running, the engine malfunctions and driveability deteriorates. Therefore, in this example, after detecting the phase shift, the throttle valve control is switched from the open loop control to the feedback control, and the throttle valve control is continued.

In the above feedback control, auxiliary control using the output from the throttle sensor (FIG. 1) is performed. As a result, the throttle valve is corrected so that the difference between the number of steps caused by the phase shift and the throttle valve opening becomes zero. Then, when the vehicle is in a safe state, for example, when the speed is zero and the accelerator pedal is zero, initialization is performed and the open loop control is performed again. By this,
Prevents engine malfunction and drivability deterioration.

FIG. 5 shows the above control state. That is, normally, open loop control is performed, but when phase deviation occurs, feedback control is switched to. Further, when the vehicle is in the above-mentioned safe state, initialization is performed and the open loop control is performed again. for that reason,
In the present invention, as shown in the figure, the target opening slightly decreases at the time of the phase shift, but the target opening is normally controlled by the feedback control. On the other hand, in the prior art, when a phase shift occurs, the step motor is once stopped (dotted line in the figure), so that problems such as engine malfunction occur.

Next, the operation and effect of this example will be described with reference to the flow charts of FIGS. In this example, as described above, the rotor vibration can be suppressed when the step motor is stopped (Example 1), and the load out-of-step is prevented by predicting the electric load and lowering the maximum pulse rate (Example 2). ), And a method that allows normal throttle valve control to be continued even when the above-mentioned phase shift or step out occurs.

That is, first, in FIG. 8, in 301,
It is determined whether or not the target throttle value (final throttle position) is the same as the actual throttle position. If they are the same, the step motor is stopped because the target opening has been reached. Then, the procedure proceeds to 306, and as shown in the first embodiment, it is determined whether the excitation state of the throttle, that is, the excitation state when the step motor is stopped is the one-phase excitation or the two-phase excitation. If it is one-phase excitation, the routine proceeds to 307, where the target number of steps is reduced by one and the two-phase excitation state is set. Then, the next throttle valve control is continued. These are the same as in the first embodiment.

On the other hand, in 301, when the throttle target value does not match the actual throttle value, the routine proceeds to 302, where it is judged whether the electric load switch of the air conditioner or the like is ON, as shown in the second embodiment. To do. If it is ON, the routine proceeds to step 303, where the maximum pulse rate is reduced in anticipation of a drop in battery voltage and throttle valve control is continued. If the load switch is not ON at 302, control continues as it is, and the process proceeds to 304. And 30
In No. 4, during throttle valve control, it is judged from the signal from the throttle sensor whether or not the command value of the throttle opening and its actual value match.

The above throttle command value means an ECU (motor control unit) for opening the throttle valve to a target position.
Is the value emitted in each cycle. Then, at 304, if the above two values are the same, proceed to 305,
Continue to drive the step motor with open loop control. On the other hand, if the two values do not match at 304,
In other words, if a phase shift or step out occurs, proceed to 308,
The control method of the step motor is changed to feedback control. Then, when the vehicle is in a safe state, that is, when the speed is zero, the accelerator depression amount is zero, or 1G (energization to the ignition coil) is zero, the vehicle is initialized and returned to the open loop control.

During the open loop control, as shown in FIG. 6, first, at 401, the accelerator position detecting means 42 (FIG. 1) detects the accelerator position to set the target opening of the throttle valve. Next, at 402, the target opening is converted into the number of steps, and at 403, the step motor is driven according to the above-mentioned target number of steps. on the other hand,
At the time of the feedback control, as shown in FIG.
At 01, the target opening is set similarly to 401 in FIG. 6, and based on that, the step motor is driven at 502 to detect the deviation between the target opening and the actual throttle opening. Then, in 504, it is judged whether or not the deviation is zero, and if it is zero, the feedback control ends and the control is changed to open loop control.

This zero deviation means that when the vehicle is in a safe state,
This is the case when initialization is performed as described above. If the deviation is not zero, the process returns to 502 and the feedback control is continued. As described above, according to this example, when the step motor is stopped, the two-phase excitation is used to suppress the vibration of the rotor to improve the responsiveness of the throttle valve control. By predicting the decrease and reducing the maximum pulse rate, load out-of-step can be prevented, and when phase out-of-step occurs, the open-loop control can be changed to the feedback control and the throttle valve control can be continued.

[Brief description of drawings]

FIG. 1 is a block diagram of a throttle valve control device according to a first embodiment.

FIG. 2 is a flowchart of throttle valve control according to the first embodiment.

FIG. 3 is an explanatory diagram of throttle valve control according to the second embodiment.

FIG. 4 is a flowchart of throttle valve control according to the second embodiment.

FIG. 5 is an explanatory diagram of throttle valve control according to the third embodiment.

FIG. 6 is a flowchart at the time of open loop control in the throttle valve control of the third embodiment.

FIG. 7 is a flowchart of feedback control in throttle valve control according to the third embodiment.

FIG. 8 is a flowchart of throttle valve control according to the third embodiment.

FIG. 9 is a vibration damping diagram for one-phase excitation and two-phase excitation when the step motor is stopped.

[Explanation of symbols]

 1. ． ． Engine, 2. ． ． Step motor, 25. ． ． Throttle valve, 3. ． ． Motor control device, 41. ． ． Accelerator pedal,

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuo Hara 1-1, Showa-cho, Kariya city, Aichi prefecture

Claims (1)

[Claims] 1. A throttle valve for adjusting the amount of air taken into the engine, a 1-2 phase excitation step motor for driving the throttle valve, and a motor control device for controlling the drive of the step motor. Further, the motor control device, when the throttle valve reaches the target opening and the step motor is stopped, the excitation state determination means for determining whether the excitation state is one-phase excitation or two-phase excitation, and 1. In the case of phase excitation, the throttle valve control device is provided with step reducing means for reducing the target number of steps of the step motor by one.