JP2002138858A - Electronic throttle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve stable opening control with no hunting when feedback controlling an electronic throttle using a detection system and a control system both of which are of discrete types. SOLUTION: This electronic throttle control device inputs a target opening TAR set by an acceleration sensor 8 and an AD value TA for an actual opening detected by a throttle sensor 6 to a microcomputer 11 and outputs a controlled variable DUTY calculated from a deviation between these input values from the microcomputer 11 to a motor 5 to feedback control the electronic throttle 1 with PWM control. The microcomputer 11 periodically controls the current width of an ON-pulse at a required duty ratio to control an output current to the motor 5. The microcomputer 11 sets a control resolution, at the time when the microcomputer 11 controls the electronic throttle 1 with the output of the controlled variable DUTY, to be higher than an input resolution during input of the actual opening TA.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic throttle control device in which a throttle valve for opening and closing an intake passage of an engine is driven by a motor.

[0002]

2. Description of the Related Art Conventionally, for example, an electronic throttle control device used for an automobile engine or the like has been known.
The electronic throttle control device includes an electronic throttle for opening and closing a linkless type throttle valve provided in an intake passage of an engine by an actuator such as a motor, and a controller for controlling the motor. The controller is, for example, an electronic throttle (throttle valve) based on the amount of operation of the accelerator pedal by the driver.
Set the target opening of. The controller performs feedback control of the motor based on an opening deviation between the set target opening and the actual opening of the throttle valve detected by the throttle sensor so that the actual opening becomes the target opening. Control the electronic throttle.

Here, an actuator having a characteristic in which the opening of the throttle valve (throttle opening) is determined by the value of the supplied control current (for example, “the value of the on-pulse duty ratio by PWM control”) as the electronic throttle. Some have been used. Examples of this type of actuator include an "electromagnetic rotary actuator" disclosed in Japanese Utility Model Laid-Open Publication No. Sho 62-188677, and
There is an "actuator" disclosed in Japanese Patent No. 308211. For example, in an electronic throttle using an “electromagnetic rotary actuator” disclosed in Japanese Utility Model Laid-Open Publication No. Sho 62-188677, a change in an exciting force caused by current control (for example, “duty ratio control”) of a coil provided in a stator is performed. A rotating force is applied to the magnetized rotor paired with the stator, the throttle valve connected to the rotor is rotated in the opening direction, and the throttle valve is rotated and stopped at an angular position determined by the exciting force together with the rotor. .

FIG. 6 shows an example of the operation characteristics of the electronic throttle as described above. In this case, 20-80%
In the range of the duty ratio, the throttle opening shows a substantially linear change characteristic with respect to the duty ratio. When an electronic throttle having such a characteristic is controlled by a controller, as shown in FIG.
Is the output resolution (minimum unit of duty ratio control) determined by the performance of the microcomputer used in the controller.
Will be determined by In this case, the output of the throttle sensor is obtained by converting the analog sensor output value indicated by a two-dot chain line in FIG.
It is digitally converted to a / D conversion value. Therefore,
The input resolution ΔVTA when the microcomputer inputs the output from the throttle sensor is determined by the conversion resolution ΔTA related to the throttle opening. By performing feedback control of the electronic throttle as described above by the controller, the throttle opening can be precisely controlled.

[0005]

However, in the conventional electronic throttle control device, both the input resolution of the microcomputer with respect to the output from the throttle sensor used for feedback control and the resolution of control of the electronic throttle by the microcomputer are discrete systems. (Digital), there may be a slight difference between the input value and the output value of the microcomputer or a difference in the absolute value level, and there is a problem that hunting occurs in the throttle valve.

That is, as shown in FIG.
In Case 1 in which TA is smaller than the control resolution LTA, the detected value and the output value do not match due to a difference in absolute value. Also, as shown in FIG.
Even in Case 2 where A and the control resolution LTA are the same, the detected value and the output value may not match due to a slight shift. In these cases, when the target opening is set to “t3” as a detection value in an attempt to perform feedback control of the electronic throttle, when the output value becomes “d2”, the detection value becomes “t2”, and the throttle valve is controlled to open. Is done. Thus, when the output value becomes “d3”, the detection value becomes “t4”, and the throttle valve is controlled to the closed side. Therefore, the output value is repeatedly switched between "d2" and "d3", and hunting is generated in the throttle valve.

The problem of this type of hunting is that if the friction around the throttle valve is relatively large, the hunting may be offset by the friction.
It is rarely a problem. However, in the future, when the electronic throttle is improved and the friction is reduced, hunting countermeasures are required to execute more accurate throttle control.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a feedback control of an electronic throttle using a detection system and a control system of discrete systems, which is stable without hunting. It is an object of the present invention to provide an electronic throttle control device capable of realizing the controlled opening degree.

[0009]

According to a first aspect of the present invention, a target opening set by target opening setting means and an actual opening detected by an actual opening detecting means are provided. In the electronic throttle control device, the electronic throttle is feedback-controlled by inputting the opening degree to the control means and outputting a control amount calculated from the deviation between the target opening degree and the actual opening degree from the control means. The control resolution when the control means controls the electronic throttle by outputting the control amount is set to be higher than the input resolution when the actual opening degree detected by the means is input.

According to the configuration of the present invention, in the electronic throttle control device, the set target opening and the detected actual opening are controlled so that the actual opening of the electronic throttle approaches the required target opening. Input to the means. Then, a control amount calculated from the deviation between the target opening and the actual opening is output from the control means, so that the electronic throttle is feedback-controlled. Here, with respect to the input resolution when the control means inputs the actual opening output from the actual opening detection means, the control when the control means controls the electronic throttle by outputting a control amount to the electronic throttle. Resolution is set high. Therefore, when the actual opening converges to a certain target opening, a control position of a control amount corresponding to a detection position of a certain actual opening always exists.

According to another aspect of the present invention, an electronic throttle for opening and closing a throttle valve by an actuator, and the actuator comprises a PW
A characteristic for determining the opening of the electronic throttle according to the duty ratio by the M control, target opening setting means for setting the target opening of the electronic throttle, and detecting the actual opening of the electronic throttle. And a digital value of the actual opening detected and a target opening to be set, and a PWM calculated from a deviation between the target opening and the actual opening.
A control means for outputting a control amount to an actuator and performing feedback control of the electronic throttle to control the actual opening to a target opening. The control resolution for controlling the electronic throttle by the control means outputting the PWM control amount is set to be higher than the input resolution.

According to the configuration of the present invention, in the electronic throttle control device, the target opening and the actual opening set by the target opening setting means are set so that the actual opening of the electronic throttle approaches the required target opening. The digital value of the actual opening detected by the detection means is input to the control means. Then, a PWM control amount calculated from the deviation between the target opening and the actual opening is output from the control means to the actuator, and the electronic throttle is feedback-controlled. Here, with respect to the input resolution at the time when the control means inputs the actual opening output from the actual opening detecting means, the control means applies PWM control to the electronic throttle.
By outputting the control amount, the control resolution for controlling the electronic throttle is set high. Therefore, when the actual opening converges to a certain target opening, a control position of the PWM control amount corresponding to the detection position of the certain actual opening always exists.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying an electronic throttle control device of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a schematic configuration of the electronic slot control device. The electronic throttle control device is an electronic throttle 1
And an electronic control unit (ECU) 2 for controlling the electronic throttle 1. The electronic throttle 1 is for adjusting the output of an automobile engine (not shown), and opens and closes a throttle valve 4 provided in a bore 3 of a throttle body constituting an intake passage of the engine by a motor 5 as an actuator. The throttle valve 4 is driven, and the actual opening (actual opening) VTA of the throttle valve 4 is detected by the throttle sensor 6. The throttle valve 4 is a linkless type that does not mechanically work with the operation of the accelerator pedal 7. That is, the throttle valve 4 is opened and closed by receiving the driving force of the motor 5 controlled by the ECU 2 based on the operation amount of the accelerator pedal 7 detected by the accelerator sensor 8.

The throttle valve 4 is rotatably supported by a throttle shaft 9 provided through the bore 3 of the throttle body. The motor 5 is provided at one end of the throttle shaft 9 and the throttle sensor 6 is provided at the other end. The motor 5 is a torque motor. This motor 5
Has a characteristic of determining the opening of the electronic throttle 1 (throttle valve 4) according to the duty ratio by the PWM control.

The throttle sensor 6 is constituted by, for example, a potentiometer. The accelerator sensor 8 sets the target opening TAR of the throttle valve 4 by setting the amount of operation of the accelerator pedal 7 by the driver to the target opening TAR.
And corresponds to the target opening setting means of the present invention. This sensor 8 is constituted by, for example, a potentiometer.

As shown in FIG. 1, the ECU 2 includes a microcomputer 11 and an A / D converter 12.
And a drive circuit 13. The microcomputer 11 supervises the control of the electronic throttle 1, and corresponds to the control means of the present invention. As is well known, the microcomputer 11 includes a central processing unit (CPU), a read / write memory (RAM), a read-only memory (ROM), and the like. The ROM contains
A control program for the electronic throttle 1 is stored. The A / D converter 12 converts an analog signal output from the throttle sensor 6 into a digital signal and outputs the digital signal to the microcomputer 11. The drive circuit 13 receives a control current output from the microcomputer 11 and outputs a drive current to the motor 5.

In FIG. 1, an analog signal relating to the actual opening degree VTA output from the throttle sensor 6 is converted into a digital actual opening degree TA by the A / D converter 12, and the digital actual opening degree TA is calculated. It is input to the microcomputer 11. Target opening degree TA output from accelerator sensor 8
The analog signal related to R is directly input to the microcomputer 11.

The microcomputer 11 controls the motor 5 by processing the input signals relating to the actual opening TA and the target opening TAR in accordance with the PID control method. That is, the microcomputer 11 determines the target opening degree T based on the value of each input signal.
The value of the opening deviation ERR of the actual opening TA with respect to AR is calculated, and the value of the control amount VPID by the PID control is calculated based on the value of the opening deviation ERR according to a predetermined formula.
Then, the microcomputer 11 outputs a drive current corresponding to the value of the control amount VPID to the motor 5 through the drive circuit 13, and controls the coil current of the motor 5. As a result, the drive amount of the motor 5 is controlled to bring the actual opening TA of the throttle valve 4 closer to the target opening TAR.

Next, the electronic throttle control will be described. FIG. 2 is a flowchart showing the contents of an electronic throttle control program executed by the microcomputer 11. The microcomputer 11 executes this routine periodically at predetermined time intervals.

In step 100, the microcomputer 11 sets the P based on the target opening TAR detected by the accelerator sensor 8.
The value of the control amount VB by the WM control is calculated. Microcomputer 1
1 performs this calculation by referring to, for example, function data (map data) having characteristics as shown in FIG.

In step 110, the microcomputer 11 calculates a value of an opening deviation ERR between the input value of the target opening TAR and the digital value of the actual opening TA.

In step 120, the microcomputer 11 calculates the value of the proportional term VP, which is one of the feedback correction terms, based on the value of the opening deviation ERR. The microcomputer 11 calculates the value of the proportional term VP according to the following equation (1). VP = KP * ERR (1) Here, “KP” is a proportional constant that is one of the feedback control gains.

At step 130, the microcomputer 11 calculates the value of the integral term VI, which is one of the feedback correction terms, based on the value of the opening deviation ERR. The microcomputer 11 calculates the value of the integral term VI by the following equation (2). VI = Σ (KI * ERR) (2) Here, “KI” is an integration constant that is one of the feedback control gains.

In step 140, the microcomputer 11 determines a P based on the calculated control amount VB and the terms VP and VI.
The value of the control amount VPID for ID control is calculated. The microcomputer 11 calculates the value of the control amount VPID by the following equation (4). VPID = VB + VP + VI (3)

In step 150, the microcomputer 11 determines the target opening TA based on the value of the calculated control amount VPID.
The value of the duty ratio DUTY corresponding to R is calculated. The microcomputer 11 calculates the duty ratio DUTY by the following equation (4).
Is calculated. DUTY = K * VPID (4) where "K" is a conversion coefficient.
Y means, as shown in FIG. 3, a ratio d2 in one cycle T of the energization width of the ON pulse that is periodically controlled in the PWM control.

At step 160, the microcomputer 11 determines the least significant bit number LS of the calculated value of the duty ratio DUTY.
It is determined whether or not B is “1”. Here, when the least significant bit number LSB is “1”, in step 161,
The microcomputer 11 sets the averaging process request flag XAV to “1” in order to increase its own output resolution LDT.
On the other hand, if the least significant bit number LSB is not “1” in step 160, the microcomputer 11 proceeds to step 162
Then, the averaging process flag XAV is set to “0”, and in step 163, the timing flag XT is set to “0”.

Thereafter, step 161 or step 16
In step 170, the microcomputer 11 determines whether the averaging process flag XAV is "1". Here, if the flag XAV is not “1”, the microcomputer 11 shifts the processing to step 190 as it is.

On the other hand, if the averaging process flag XAV is "1" at step 170, the microcomputer 11 shifts the process to step 180 because there is an averaging process request for the duty ratio DUTY of the PWM control. Then, in step 180, the microcomputer 11 determines whether or not the timing flag XT is “1”. Here, if the timing flag XT is not “1”, the microcomputer 11
Is the duty ratio D calculated in step 181
The value obtained by adding “1” LSB to UTY as the value of the output resolution LDT of the microcomputer 11 is the current duty ratio D
It is calculated as UTY. Thereafter, in step 182, the microcomputer 11 sets the timing flag XT to "1" so as not to perform the process of step 181 next time.

On the other hand, if the timing flag XT is "1" at step 180, the microcomputer 11 proceeds to step 183 to execute the process at step 181 next time.
The timing flag XT is set to “0”.

Then, step 182 or step 18
The microcomputer 11 outputs the control current of the duty waveform to the drive circuit 13 based on the calculated value of the duty ratio DUTY at Step 190 after shifting from 3 and temporarily ends the subsequent processing.

Therefore, if the averaging process flag is not "1" at step 170, that is, if the output averaging process is not requested, as shown in FIG.
, A control current having a duty waveform with a predetermined ratio d2 as a duty ratio DUTY is periodically output to the drive circuit 13. On the other hand, if the averaging process flag is "1" at step 170, that is, if the output averaging process is requested, the output is performed as shown in FIG. That is, the predetermined ratio d2 in one cycle T is set to the duty ratio D
A control current having a duty waveform having a duty ratio DUTY of a predetermined ratio d3 obtained by adding the output resolution LDT of the microcomputer 11 to every other UTY is output to the drive circuit 13 periodically.

As described above, in the electronic throttle control device of this embodiment, the actual opening degree VTA of the electronic throttle 1 (throttle valve 4) is set to the required target opening degree TAR.
The value of the target opening TAR set by the accelerator sensor 8 and the value of the actual opening TA detected by the throttle sensor 6 and converted to a digital value by the A / D converter 12 are stored in the microcomputer 11 in order to approach Is entered. Further, the microcomputer 11 calculates the value of the opening deviation ERR from the values of the target opening TAR and the actual opening TA. Then, a value of the duty ratio DUTY, which is a control amount for the PWM control, is calculated by the microcomputer 11 from the value of the opening degree deviation ERR, output to the motor 5, and the electronic throttle 1 (motor 5) is feedback-controlled.

Here, the input resolution ΔVTA when the microcomputer 11 inputs the value of the actual opening TA output from the throttle sensor 6 and A / D converted is compared with the microcomputer 1.
The control resolution LTA when the electronic throttle 1 (motor 5) is controlled by setting the duty ratio DUTY to output a duty waveform is set high. That is, the control resolution LTA of the control system of the microcomputer 11 is set to be higher than the input resolution ΔVTA of the detection system of the microcomputer 11. Therefore, when the value of the actual opening TA converges to the value of the target opening TAR, the actual opening T
A control position of the duty ratio DUTY corresponding to the detection position of A always exists. As a result, stable opening control can be realized without causing hunting in the electronic throttle 1. That is, the stability of the opening control is improved by restricting the resolution of the input side of the microcomputer 11 to the resolution of the output side or less and calculating the output value.

Here, the averaging process will be described in detail. As shown in FIG. 4, by performing the averaging process of the duty waveform output, the energization width of one cycle T is set to the ratio d2.
Are alternately output with the ON pulse with the energization width of one cycle T being the ratio d3. This allows
On average, the duty ratio DU at the ratio of (d2 + d3) / 2
TY is output, whereby the control resolution LTA of the microcomputer 11 can be doubled. That is, the microcomputer 11
The microcomputer 11 sets the control resolution LTA by outputting the duty waveform to the control system by the duty ratio DUTY higher than the input resolution ΔVTA from the detection system when the actual opening degree TA of the digital value is input. . That is, the control resolution LTA for the control system of the microcomputer 11
Is the input resolution ΔVTA for the detection system of the microcomputer 11
Set to be higher. Thereby, as shown in FIG. 5, when the target opening degree TAR is set to a predetermined detection position t3 in the detection system, the control position of the duty ratio DUTY is a ratio (d2 + d3) to the detection position t3.
/ 2 makes it possible to perform control to make them substantially coincide with each other.

On the other hand, in case 2 shown in FIG. 10, even if the resolutions of the detection system and the control system are exactly the same,
The absolute values of the resolutions are shifted from each other by 互 い に.
Therefore, in this case, hunting occurs in the electronic throttle 1 not only in the detection position t3 but also in any opening degree range.

In FIG. 5, the configuration was such that hunting did not occur in the electronic throttle 1. However, in FIG. 5, the ratio d1 and the detection position t
2 for ratio (d1 + d2) / 2 or ratio d2, for detection position t3, ratio (d2 + d3) / 2,.
Becomes Therefore, from the detection position t1 to the detection position t2,
When the value changes from the detection position t2 to the detection position t3,
From ratio d1, ratio (d1 + d2) / 2, ratio (d1 + d)
The control position changes from 2) / 2 to the ratio (d2 + d3) / 2, or from the ratio d1 to the ratio d2, and from the ratio d2 to the ratio (d2 + d3) / 2. Therefore, the actual opening degree VTA
In this case, there is a mixture of the case of moving by the control resolution LTA and the case of moving by half the control resolution LTA, and the actually controlled resolution varies. This also occurs because the input and output to the microcomputer 11 perform feedback control between discrete systems (digital), and in order to improve the resolution controlled in the next step, the resolution of the control system must be set to an analog value as much as possible. Need to be closer to.
For this purpose, the averaging process shown in FIG. 4 is useful.

Here, when the friction around the throttle valve 4 is relatively large, the hunting may be canceled by the friction, and the hunting of the throttle valve 4 may not substantially cause a problem. On the other hand, when the mechanical improvement of the electronic throttle 1 advances and the friction of the throttle valve 4 does not become a problem, the hunting prevention effect by the averaging process is performed in order to execute the throttle control with higher accuracy. Can be particularly effective.

It should be noted that the present invention is not limited to the above-described embodiment, and may be implemented by appropriately changing a part of the configuration without departing from the spirit of the invention.

[0040]

According to the first aspect of the present invention,
In a system that performs feedback control of an electronic throttle using a detection system and a control system of discrete systems, stable opening control can be realized without hunting.

According to the second aspect of the present invention, similarly, in a system in which the electronic throttle is feedback-controlled using a detection system and a control system of discrete systems, a stable opening control without hunting occurs. Can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an electronic throttle control device according to an embodiment.

FIG. 2 is a flowchart showing a control program for an electronic throttle.

FIG. 3 is also a waveform diagram of an on-pulse.

FIG. 4 is also a waveform diagram of an on-pulse.

FIG. 5 is a chart showing controllability.

FIG. 6 is a graph showing an operation characteristic of an electronic throttle according to the related art.

FIG. 7 is a graph showing the relationship between control resolution and output resolution.

FIG. 8 is a graph showing an input resolution of a detection value from a throttle sensor.

FIG. 9 is also a chart showing controllability.

FIG. 10 is also a chart showing controllability.

[Explanation of symbols]

 Reference Signs List 1 electronic throttle 4 throttle valve 5 motor (actuator) 6 throttle sensor (actual opening detection means) 8 accelerator sensor (target opening setting means) 11 microcomputer (control means)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Ikeda ▲ Shin ▼ Osamu 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Satoshi Kikuchi 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Stock In-house F-term (reference) 3G065 CA00 DA05 DA06 DA15 FA12 GA41 GA46 HA21 HA22 JA04 JA09 JA11 KA02 3G301 JA06 LA03 LB02 LC03 NA03 NA04 NA05 NA06 NA08 NB15 NB18 NC04 ND02 ND05 ND41 NE01 NE06 PA11A PA11Z PF03Z

Claims (2)

[Claims] 1. A target opening set by a target opening setting unit and an actual opening detected by an actual opening detecting unit are input to a control unit, and the target opening and the actual opening are compared with each other. An electronic throttle control device configured to feedback-control the electronic throttle by outputting a control amount calculated from the deviation from the control unit, wherein the control unit inputs the detected actual opening degree with respect to an input resolution. An electronic throttle control device, wherein the control means sets the control resolution at the time of controlling the electronic throttle by outputting the control amount to be high. 2. An electronic throttle for opening and closing a throttle valve by an actuator, wherein the actuator has a characteristic of determining an opening of the electronic throttle according to a duty ratio by PWM control, and a target opening of the electronic throttle. Target opening setting means for setting the actual opening degree of the electronic throttle, actual opening degree detecting means for detecting the actual opening degree of the electronic throttle, digital value of the set target opening degree and the detected actual opening degree A control for inputting and outputting a PWM control amount calculated from a deviation between the target opening and the actual opening to the actuator and performing feedback control of the electronic throttle so that the actual opening approaches the target opening. An electronic throttle control device comprising: an input disassembly unit for inputting the detected actual opening degree by the control unit. Respect, the electronic throttle control device being characterized in that set high control resolution when said control means controls said electronic throttle by outputting the PWM control amount.