JP2002070588A - Electronic control throttle device - Google Patents

Abstract

(57) Abstract: To improve the durability of an actuator or the like used for throttle control by limiting the current in a throttle control opening holding current control band. A target signal of the throttle valve is calculated by inputting a detection signal relating to the operation amount of the pedal. Based on the difference between the target opening and the actual opening actually detected, the PID controller 1
11 performs feedback control of the current of the drive motor of the throttle valve. When the deviation between the target opening and the actual opening is in a convergence state, there is provided a current limiting unit 150 for limiting the control current of the drive motor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electronically controlled throttle device for an engine.

[0002]

2. Description of the Related Art Conventionally, there has been known a throttle valve control apparatus for an automobile called an "electronic control throttle system" which controls a degree of opening of a throttle valve by driving a DC motor in accordance with an operation amount (depression amount) of an accelerator pedal. I have.

In this vehicle throttle valve control device, current control of an actuator such as a DC motor is performed in accordance with an accelerator opening detection signal (accelerator opening sensor output signal) corresponding to an accelerator pedal depression amount.
The drive control of the motor controls the opening of the throttle valve to control the intake air amount. At this time, the DC motor is controlled so that there is no deviation between the throttle target opening determined by the signal from the accelerator opening sensor and the throttle opening sensor signal (actual opening) for detecting the opening of the throttle valve. In addition, feedback control based on proportional / integral / differential control (PID control) or similar control (hereinafter, simply referred to as “PID control”) is executed (for example, Japanese Patent Application Laid-Open No. H11-270367).

An electronically controlled throttle device having a default mechanism (a mechanism for returning or holding a throttle valve to a predetermined opening position when there is no throttle control) has also been put to practical use. In connection with this, for example, in JP-A-11-182308, in the region before and after the default opening, the region before and after the default opening is considered in consideration of the throttle control valve characteristic in which the actual opening of the throttle valve greatly differs from the target opening. A technique is known in which a deviation between a target opening and an actual opening is calculated in a throttle opening operation range and a current command value to a motor is corrected in accordance with the deviation.

[0005]

The above-mentioned P
In the ID control, even if the target opening and the actual opening coincide with each other, slight fluctuation (fluctuation) of the throttle sensor value occurs due to electric noise added to the sensor output or a slight displacement of the throttle valve. It always occurs in the opening or closing direction. Therefore, the current is continuously supplied in order to eliminate the deviation that occurs.

FIG. 4 shows operating characteristics until the throttle valve is controlled to reach a control range for maintaining the actual opening at the target opening. The vertical axis is the throttle opening, and the horizontal axis is the time axis. FIG. 5 shows an enlarged control range (the control range is a control range for keeping the throttle opening at the target value) when the actual opening in FIG. 4 reaches the target opening. This indicates a control current band (this control current is a current for maintaining the throttle opening at the target opening, and may be hereinafter referred to as a “holding control current”).

In FIG. 5, the horizontal axis represents the time axis, and the vertical axis represents the state of the control current for holding the actual opening based on a deviation (difference between the target opening and the actual opening) of 0. Even if the actual opening degree substantially coincides (in an operating state in which the deviation between the target opening degree and the actual opening degree converges), as described above, the slight fluctuation (variation) of the throttle sensor value always occurs in the opening direction or the closing direction. Occurs in the direction. If the current continues to flow in order to eliminate the deviation that occurs, the small peak current A
Is seen as a phenomenon that occurs repeatedly in pulses,
This causes a spark to be generated between the brush and the commutator of the DC motor, thereby reducing the durability of the motor brush and accelerating wear of movable components such as gears.

An object of the present invention is to provide an electronically controlled throttle device for an automobile which can solve such a problem and improve the durability of an actuator or the like used for throttle control.

[0009]

The present invention is basically configured as follows in order to achieve the above object.

That is, a target opening of the throttle valve is calculated by inputting at least a detection signal relating to the operation amount of the accelerator pedal, and a drive motor for the throttle valve is calculated based on a deviation between the target opening and the actually detected actual opening. An electronically controlled throttle device that feedback-controls the current of the pre-drive motor when the deviation between the target opening and the actual opening converges within a predetermined range, that is, in a holding current control band of the throttle opening. (DC motor) is provided with a current limiting unit for limiting the control current.

With such a configuration, by imposing a limit on the minute peak current A generated in the holding current control band as shown in FIG. 5, a spark is generated between the brush and the commutator of the throttle actuator (DC motor). It is possible to suppress the occurrence and to suppress the minute operation of the speed reduction mechanism.

[0012] Such current limiting is performed, for example, on the condition that the deviation between the target opening and the actual opening is equal to or less than a predetermined value and the state lasts for a predetermined time or more. The control current of the drive motor is limited by assuming that the current has entered the band.

Alternatively, a means for changing the level of the current limit value from the absolute average value of the deviation between the target opening and the actual opening is proposed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an electronically controlled throttle device according to the present invention will be described in detail with reference to the illustrated embodiment.

FIG. 1 shows the overall configuration of an electronic control throttle device (throttle valve control device) according to a first embodiment of the present invention.

The input I / in the throttle control module 1
The output signals of the accelerator sensors 25 and 26 from the accelerator unit 6 are input to an F (A / D converter) 109, and the output signals of the throttle sensors 16 and 17 for detecting the throttle opening from the throttle unit 7 as well. Is entered. 24 is an accelerator pedal.

The throttle control module 1 is composed of, for example, a combination of a microcomputer and a motor drive circuit, and calculates an actual opening degree of the throttle valve 18 from output signals of the throttle sensors 16 and 17.
1. A target opening setting unit 102 that calculates a target opening based on output signals of the accelerator sensors 25 and 26 (which may also include a command signal from an engine control module (not shown)). A PID control unit 111 that performs PID control of the throttle opening based on the deviation of the opening,
Motor current control section 103 for controlling the current of the throttle drive motor (DC motor) based on the ID control value, current limit section 1 for limiting the motor drive current (motor control current)
50, motor drive circuit section 125, throttle sensor 16
And a failure determination unit 104 that determines the failure of the accelerator sensor or the throttle sensor from the input values of the acceleration sensor 17 and the output signals of the accelerator sensors 25 and 26.

The throttle unit 7 includes a throttle valve 18
And a DC motor 14 and a gear 15 for rotationally driving the throttle valve 18, and two throttle sensors 16 and 17 are arranged.

The throttle control module 1 diagnoses whether or not these sensors are abnormal based on the input detection signals of the accelerator sensors 25 and 26 and the throttle sensors 16 and 17. It is determined to be abnormal. Further, a deviation between the throttle control amount and the output values of the throttle sensors 16 and 17 is obtained.
Diagnosis of abnormal control.

If the sensor is normal, the target opening setting unit 1
02 determines the accelerator opening based on the signals of the accelerator sensors 25 and 26, calculates the target opening of the throttle valve, and stores the target opening in the PID control unit 111.

The actual opening detecting section 101 calculates the actual opening based on the detection signals of the throttle sensors 16 and 17, and stores the actual opening value in the PID control section 111.

The PID control unit 111 calculates a PID value based on the deviation between the target opening and the actual opening, and
Reference numeral 03 controls the drive of the motor 14 using the motor drive circuit unit 125 based on the calculation result of the PID control unit 111, and controls the rotation of the throttle valve 18.

The motor drive circuit 125 includes a battery 18
Is supplied through a relay 19. This relay 1
Reference numeral 9 denotes a configuration in which when a serious abnormality occurs, the engine is cut off by the engine control module, and the driving of the motor 14 is forcibly stopped. However, the operation of the relay 19 is out of the scope of the present invention.

When the actual opening reaches the target opening by the above-described throttle control and is in an operating range where the target opening is maintained, in other words, the deviation between the target opening of the throttle and the actual opening is within a predetermined range. When the motor current is in the holding current control band for holding the throttle opening at the target value and the motor current is in the holding current control band for suppressing the minute peak current A (FIG. 5) appearing in the holding current band. Then, the current limiting unit 150 functions.

Here, the operation of the motor control section 103 and the current limiting section 150 for limiting the current will be described with reference to the flowchart of FIG.

First, the motor control unit 103 determines that the deviation between the target opening and the actual opening in the throttle control is equal to or less than a predetermined value (in FIG. 8, the deviation <1 degree), and the state continues for a predetermined time or more (FIG. 8). It is determined that the throttle drive motor current is in the holding current control band on the condition that the current limit is 100 ms), and the current limiting unit 103 is caused to function. If it is determined that the above condition is not satisfied and the current is not in the holding current control band,
The motor control section 103 controls the motor drive circuit section 125 based on a normal PID control value.

If it is determined that the current is in the holding current control band, the current limiter 150 determines the motor current (based on PID control) in the holding current control band as described later.
Place restrictions on

That is, in the embodiment of the current limit determination, the deviation E between the target throttle opening and the actual opening is monitored. Threshold ThE while E is continuously Te (sec)
If the current value is within the range, the current limitation is permitted. Otherwise, the current limitation is not permitted. Here, during the Te (second), the actual motor drive current value is also monitored and stored in the current limiting unit 150. Specifically, the average value Iav of the motor drive current (motor control current) during this period is calculated and recorded. Since the motor driving method when the current limitation is not performed is the same as that in the normal case, the motor driving method when the current limitation is possible will be described below.

FIG. 6 is a time chart of the current limiting operation of the holding control current band when the current limiting is possible. In this case, a current limit threshold (current limit width) a is defined for Iav stored in the current limiter 150. Here, the limitation of the motor control current is limited to a value that can take only a value between (Iav-a) and (Iav + a). That is, the range of the motor current limit value is set to Iav ± a. Here, the value of a is a numerical value equal to or greater than zero. If the sensor output value was observed to change due to electrical noise, or vibration of the throttle valve, etc., when the motor drive current was calculated based on the sensor output value, the calculated value was less than (Iav-a) Sometimes it is replaced by (Iav-a), and when it exceeds (Iav + a), (Ia
v + a).

If the motor is driven based on the value of this result,
Even if the sensor output value changes in pulses due to electrical noise or the like, it is possible to suppress the minute peak current A in the holding current control band from becoming unacceptably large and to suppress the occurrence of sparks between the brush and the commutator. . In addition, the amount of driving the throttle valve can be suppressed as an effect of the current limitation. As a result, the amount of change in the position of the throttle valve can be suppressed, and movable components such as gears can be worn.

In the above description, the limit value of the motor drive current is (Iav-a) to (Iav + a).
To (Iav + a) or (Iav-a) to (Iav). Such setting of the current limiting range in one direction is effective in the following cases.

That is, the electronically controlled throttle mechanism often employs a throttle body structure provided with a default mechanism for holding the throttle valve at an initial opening (default opening) in an initial state where electronic control is not performed.

As a method of realizing such a throttle body, the opening direction is set in the opening direction from the default position, and the opening direction is set in the closing direction from the default position.
It is conceivable to incorporate springs (return spring and default spring) that generate torque.

When the throttle valve is positioned in the opening direction from the default position and is stable, and when it is detected that the throttle opening is more open,
In order to eliminate the difference between the target throttle opening and the actual opening, the throttle valve is driven in the closing direction, which is the same direction as the direction of the torque generated by the return spring. Therefore, in this case, it is not necessary to increase the current and actively drive the throttle valve in the closing direction. Conversely, when it is detected that the throttle opening has changed in the closing direction in the stable region, the throttle valve is driven in the opening direction to eliminate the deviation between the target throttle opening and the actual opening. In other words, this is the direction opposite to the direction of the torque generated by the return spring. Therefore, in this case, it is necessary to increase the current and actively drive the throttle valve in the closing direction.

On the other hand, when the throttle valve position is in the closing direction from the default position, the relationship is reversed. As described above, the range of the current limitation may be set only in the opening direction in which the current is not actively increased. When the throttle valve is in the opening direction from the default position The current limiting range in this case is from (Iav-a) to (Iav).

This is because, as shown in FIG. 7, the limit value of the motor control current in the holding current band is set in the range of Iav-a to Iav (Iav in FIG. 7), and the motor in the holding current band is more than the limit value. If the control current calculation value is going to decrease, it is replaced with a limit value. When the throttle valve is in the closing direction from the default position The current limiting range in this case is from (Iav) to (Iav + a).

In contrast to the above, the limit value of the motor control current in the holding current band is set in a range from Iav to Iav + a.
If the calculated value of the motor control current in the holding current band is larger than the limit value, it is replaced with the limit value.

In the above embodiment, the current limit threshold value a is treated as a constant value.
It may be determined stepwise according to the throttle opening.

That is, the spring load (load load) of the return spring or the default spring changes according to the change in the throttle opening, and the optimum value of the current limit value in the holding control current band also changes accordingly. It is effective if the current limit value is set correspondingly.

FIG. 2 and FIGS. 9 and 10 show the structure relating to this embodiment. In these figures, the same reference numerals as those in the embodiment of FIG. 1 indicate the same or common elements.

The difference between the present embodiment and the first embodiment is that a current limit level setting section 160 is added to the current limit section 150. The current limit level setting section 160 is set so as to change the level of the threshold value (limit width) a of the current limit value of the holding control current band according to the throttle opening to be controlled.

For example, as shown in FIG. 10, the level of the current limit value is set according to the throttle opening (actual opening or target opening) (the level may be set stepwise instead of continuously). ), The current limit level setting section 160
To memorize it.

The current limit level setting unit 160 executes the flowchart of FIG. 9 to determine the level of the current limit value from the calculated actual opening or target opening, and based on the level, determines the level of the holding control current band. Perform current limiting.

The level of the current limit value may be set so as to change the level of the current limit value from the absolute average value of the deviation between the target opening and the actual opening, instead of the above method.

In this case, current limit level setting section 160 of FIG. 2 operates as follows. That is, first, the deviation E between the target throttle opening (TAR) and the actual opening is monitored. After the filter processing is applied (hereinafter referred to as ACTfil), the actual opening degree is determined by the current limit level setting unit 160.
Is input to For this reason, the change becomes slower with respect to pulse noise which is a typical form of electric noise.

Here, one of the methods for determining the current limit threshold value a is the average absolute value of the difference between ACTfil and the target opening TAR.
The current limit threshold value a is obtained from (DEV). In the simplest case, the current limit threshold value a = F (DEV). Where F is a function of DEV. As a result, for example, when the actual opening or the target opening greatly changes and the deviation between them increases, the current limit threshold
a becomes a large value, the influence of the current limiting function becomes small, and if the target opening and the actual opening approach each other, the current limiting threshold a
Becomes small, and the control that the effect of the current limitation appears strongly can be performed. In the above, F is a function, but a method of calculating this by a table lookup may be used. The interpolation method is not particularly limited, such as linear interpolation.

FIG. 3 is a block diagram of a throttle control device according to a third embodiment of the present invention.
The configuration shown in FIG. 2 is further provided with a current limit value correction unit 170 based on the battery voltage in addition to the components shown in FIG.

Here, the battery voltage is a voltage applied to the motor.

The effect of the current limit threshold obtained in the embodiment of FIG. 2 (or the current limit threshold defined in the embodiment of FIG. 1) depends on the battery voltage. The extent of this increases and decreases with lower battery voltage. In this embodiment, the battery voltage (Vb) is monitored,
The current limit threshold value a is corrected by the current limit value correction unit according to the battery voltage. In brief, the current limit threshold a is obtained by calculating a = a × Vb / Vbs.

Here, a is a current limit threshold value before correction, V
b is the observed battery voltage, Vbs is a constant value, and represents a reference value for Vb.

[0051]

As described above, according to the present invention, by limiting the current in the holding current control band in the throttle control, the change in the motor control current based on the sensor output noise and the like is suppressed, and the brush / commutator is controlled. It is possible to improve the durability of the actuators and the like used for the throttle control by suppressing the occurrence of sparks during the rotation and suppressing the wear of the gear mechanism of the throttle.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the overall configuration of an electronic control throttle device (throttle valve control device) according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing an overall configuration of an electronic control throttle device according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing an overall configuration of an electronic control throttle device according to a third embodiment of the present invention.

FIG. 4 is an explanatory diagram showing throttle control operation characteristics until the actual opening reaches a control range for maintaining the target opening.

FIG. 5 is a diagram showing a holding current control waveform in a throttle opening holding area during conventional throttle control.

FIG. 6 is a time chart showing an example of the current limiting operation of the present invention.

FIG. 7 is a time chart showing another example of the current limiting operation of the present invention.

FIG. 8 is a flowchart showing a current limiting operation according to the first embodiment of the present invention.

FIG. 9 is a flowchart showing an operation of setting a current limit value level according to a second embodiment of the present invention.

FIG. 10 is an explanatory diagram showing a relationship between a current limit value level and an actual opening of a throttle valve according to a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Throttle control module, 7 ... Throttle body, 14 ... Motor, 18 ... Throttle valve, 102 ... Target opening setting part, 103 ... Motor control part, 111 ... PID control part, 125
... A motor drive circuit section, 150 a current limit section, 160 a current limit level setting section, 170 a current limit value level correction section.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor, Tsuguo Tomita, Hitachi, Ibaraki Pref. Within Hitachi Car Engineering (72) Inventor Hayato Sugawara 2477 Takaba, Hitachinaka-shi, Ibaraki F-term within Hitachi Car Engineering Co., Ltd. 3G065 CA24 CA27 DA05 FA05 FA11 GA41 KA36 3G084 BA05 DA04 EA02 EB15 EC08 FA10 3G301 HA01 JA15 LA03 NA03 NA04 NA05 ND01 PA11Z PF03Z

Claims (6)

[Claims] At least a detection signal relating to an operation amount of an accelerator pedal is input to calculate a target opening of a throttle valve, and a drive motor of the throttle valve is calculated based on a difference between the target opening and an actually detected actual opening. An electronically controlled throttle device that feedback-controls the current of the current control device, wherein a current limiter that limits a control current of the precursor drive motor is provided when a deviation between the target opening and the actual opening is in a converging state. Electronically controlled throttle device. 2. The control device according to claim 1, wherein the current limiter limits the control current of the drive motor on a condition that a deviation between the target opening and the actual opening is equal to or less than a predetermined value and the state continues for a predetermined time or more. The electronically controlled throttle device according to claim 1, wherein the electronic throttle device is set to: 3. The current limiter calculates an average value Iav of the control current of the drive motor when the deviation between the target opening and the actual opening is in a converging state, and determines the average current Iav and the current limit. 3. The electronically controlled throttle device according to claim 1, wherein the current limit value is set to one of Iav ± a, Iav + a, and Iav−a according to the value a for determining the width. 4. The electronically controlled throttle device according to claim 1, wherein the current limiter is set so as to change the level of the current limit value according to the throttle opening to be controlled. . 5. The current limiting unit according to claim 1, wherein the current limiting unit is configured to change a level of the current limiting value from an absolute average value of a deviation between the target opening and the actual opening.
An electronically controlled throttle device according to claim 1. 6. The electronically controlled throttle device according to claim 1, wherein the current limiter has a function of correcting the current limit value based on a battery voltage.