JP2003343286A - Electronic throttle control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the quickest malfunction of a throttle valve caused by the abnormal output of a throttle sensor, and to prevent damage to the driving system of the throttle valve. <P>SOLUTION: An electronic throttle 1 opens or closes the throttle valve 4 with a motor 5. The target opening RTA of the electronic throttle 1 is set by an acceleration sensor 8, and the actual opening VTA thereof is detected by a throttle sensor 6. An electronic control unit (ECU) 2 controls the motor 5 based on the control amount calculated from the differential between the target opening RTA and the actual opening VTA. When the output of the throttle sensor 6 is abnormal, the ECU 2 forcibly increases the input value of the actual opening VTA in an input circuit 16 correspondingly to the totally closing direction of the throttle valve 4. Besides, when there is no change in the target opening RTA, the ECU 2 regulates the calculated control amount to a predetermined value except the maximum and minimum values thereof. <P>COPYRIGHT: (C)2004,JPO

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 for controlling the operation of a throttle valve provided in an intake passage of an engine by an actuator for opening and closing the valve.

[0002]

2. Description of the Related Art Conventionally, an electronic throttle control device used in a gasoline engine or a diesel engine of an automobile or the like has been known. The electronic throttle control device includes an electronic throttle configured to open / close 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 actuator. Generally, a controller sets a target opening degree of an electronic throttle (throttle valve) based on an operation amount of an accelerator pedal by a driver. This controller feedback-controls the actuator by PID control or the like based on the 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 is set to the target opening. The electronic throttle is controlled so that the frequency becomes the same.

As an electronic throttle control device of this kind,
A technique for coping with an abnormal behavior of an electronic throttle when a throttle sensor fails is disclosed in Japanese Unexamined Patent Publication No. 3-31531, "Throttle valve control device for internal combustion engine".
Is disclosed in.

If a disconnection occurs between the input terminals of the controller from the middle of the output signal line of the throttle sensor, the voltage value output through the input circuit is irrelevant to the actual opening of the throttle valve. It becomes a very unstable value. Then, the feedback control is executed by regarding this output signal as the actual opening, and it is impossible to predict at all whether the throttle valve operates in the opening direction or the closing direction from the relationship with the target opening at that time. The opening / closing operation is very unstable, and in some cases, the throttle valve may be fully opened. In the above-mentioned conventional publication, countermeasures are taken while paying attention to such a point.

That is, in the control device of the above-mentioned conventional publication,
As shown in FIG. 11, the control unit 51 for controlling the actuator of the throttle valve includes a throttle control circuit, an input circuit 53 for removing noise from the output signal of the throttle sensor 52, and an output signal A
And an A / D converter 54 for performing D / D conversion and outputting to the throttle control circuit. Here, the input circuit 53 includes an RC filter 55 including a pair of resistors R1 and R2 and a capacitor C1 connected in series. A high resistance pull-up resistor R3 is connected between the input terminal 56 to which the throttle sensor 52 is connected and the power supply (Vcc).

According to the input circuit 53, if a disconnection should occur in the middle of the output signal line 57 connected between the throttle sensor 52 and the input circuit 53, the input circuit 53 will do.
The voltage value output from the control circuit gradually increases with a predetermined time constant, eventually reaches the power supply voltage Vcc, and the detection output is as if the throttle valve were fully opened. By performing feedback control of the actuator based on the comparison between this output signal and the target opening signal, the throttle valve is gradually closed until it is fully closed. That is, the throttle valve is always kept fully closed on the safe side, so that a situation such as an abnormal increase in engine output can be avoided.

[0007]

However, in the control device of the above-mentioned conventional publication, when the output signal line 57 of the throttle sensor 52 is broken, the sensor output signal changes to the GND level or the power supply voltage Vcc level. . At this time, the throttle control circuit drives the actuator in the direction of canceling the signal change (malfunction), and in the worst case, the throttle valve may hit the fully closed stopper at the fastest operation. In this case, the drive system of the throttle valve (for example, a speed reducer provided for the throttle valve) is damaged, and the damage may cause a new malfunction of the throttle valve. Further, since the throttle valve suddenly becomes a fully closed state, the drivability of the automobile engine may be deteriorated due to sudden deceleration, and the engine may stall in the worst case.

The present invention has been made in view of the above circumstances, and an object thereof is to mitigate the fastest operation of the throttle valve due to an abnormal output when the throttle sensor fails and to suppress damage to the drive system of the throttle valve. An object of the present invention is to provide an enabled electronic throttle control device.

[0009]

In order to achieve the above object, an invention according to a first aspect of the invention is to set an electronic throttle for opening and closing a throttle valve by an actuator and a target opening degree of the electronic throttle. Target opening setting means, actual opening detection means for detecting and outputting the actual opening of the electronic throttle, and for calculating the control amount of the actuator based on the opening deviation between the target opening and the actual opening Control amount calculation means, the control means for feedback controlling the actuator based on the control amount, and when the output of the actual opening detection means becomes abnormal, the value given to the control amount calculation means as the actual opening is set to the throttle value. In the electronic throttle control device equipped with the forced adjustment means for forcibly increasing or decreasing the valve in the direction of operating toward the safe side, When there is no change in the value given to the control amount calculating means, and the spirit that a control amount limiting means for limiting the calculation of the control amount to a predetermined value other than the maximum value and the minimum value of the control amount.

According to the structure of the above invention, the target opening value set by the target opening setting means and the actual opening value detected and output by the actual opening detecting means are respectively calculated as control amounts. Given to the means. Then, the control amount calculation unit calculates the control amount of the actuator based on the opening difference between the target opening amount and the actual opening amount, and the control unit feedback-controls the actuator based on the control amount. This allows electronic throttle (throttle valve)
The actual opening of is close to the target opening. In this case, should the actual opening detection means fail in some way and its output becomes abnormal, the value given to the control amount calculation means as the actual opening causes the forced adjustment means to move the throttle valve to the safe side. It is forcibly increased or decreased in the direction toward.
As a result, the control amount increases or decreases toward the maximum value or the minimum value, and the actual opening of the electronic throttle (throttle valve) operates toward the fully closed or fully opened state. At this time, if there is no change in the value given to the control amount calculation means as the target opening, the control amount limiting means limits the calculation of the control amount to a predetermined value other than the maximum value and the minimum value of the control amount. Therefore, the electronic throttle (throttle valve)
The operation to fully open or fully close the actual opening is alleviated.

In order to achieve the above-mentioned object, the invention according to claim 2 is an electronic throttle for opening / closing driving a throttle valve by an actuator, and a target opening setting means for setting a target opening of the electronic throttle. An actual opening detecting means for detecting and outputting the actual opening of the electronic throttle; and a control amount calculating means for calculating the control amount of the actuator based on the opening deviation between the target opening and the actual opening. When the output of the control means for feedback-controlling the actuator based on the control amount and the actual opening detection means becomes abnormal, the throttle valve operates the value given to the control amount calculation means as the actual opening to the safe side. In the electronic throttle control device equipped with the forced adjustment means for forcibly increasing or decreasing in the direction, the output abnormality of the actual opening detection means is checked for a predetermined time. Output abnormality determination means for deterministically determining the output abnormality, and when a sign of an output abnormality is observed by the output abnormality determination means, the control amount is calculated before the output abnormality is definitely determined. It is intended to include control amount limiting means for limiting the control amount to a predetermined value other than the maximum value and the minimum value.

The operation different from that of the first aspect of the present invention according to the above configuration is as follows. That is, in the unlikely event that some failure occurs in the actual opening detection means and its output becomes abnormal, the value given to the control amount calculation means as the actual opening is
The forced adjustment means forcibly increases or decreases the throttle valve in the direction toward the safe side. As a result, the control amount increases or decreases toward the maximum value or the minimum value, and the actual opening of the electronic throttle (throttle valve) operates toward the fully closed or fully opened state. At this time,
The output abnormality determination means deterministically determines the output abnormality of the actual opening detection means over a predetermined period of time.If an output abnormality symptom is observed during the determination, the output abnormality is deterministically determined. Before the control amount is calculated, the calculation of the control amount is limited to a predetermined value other than the maximum value and the minimum value of the control amount. Therefore, the operation of the electronic throttle (throttle valve) to fully open or fully close its actual opening is relaxed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] A first embodiment in which the electronic throttle control device of the present invention is embodied in an automobile engine will be described in detail with reference to the drawings.

FIG. 1 shows a schematic structure of the electronic throttle control device. The electronic throttle control device is an electronic throttle 1
And an electronic control unit (ECU) 2 for controlling it. The electronic throttle 1 is used to adjust the output of an automobile engine (not shown). The electronic throttle 1 is an engine intake passage (throttle body) 3
The throttle valve 4 provided in the vehicle is opened and closed by a motor 5 as an actuator, and the actual opening (actual opening) VTA of the valve 4 is measured by the throttle sensor 6.
It is designed to be detected by. Throttle valve 4
Is a linkless type that is not mechanically linked to the operation of the accelerator pedal 7. That is, the throttle valve 4
Is operated 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 the throttle body 3 by a throttle shaft 9 penetrating the bore 3a. The motor 5 is connected to one end of the throttle shaft 9 via a speed reducer 10, and the throttle sensor 6 is connected to the other end via an opener mechanism 11. The output shaft of the motor 5 is connected to the throttle shaft 9 via a plurality of gears 12 forming the reduction gear device 10 and the like. In this embodiment, a resin gear 12 is used for cost reduction.

The throttle sensor 6 is the electronic throttle 1
It is for detecting and outputting the actual opening VTA of the (throttle valve 4) and corresponds to the actual opening detecting means of the present invention. The sensor 6 is composed of, for example, a potentiometer. In this embodiment, the throttle sensor 6
Is equipped with two systems of potentiometers. The accelerator sensor 8 is for detecting and outputting the operation amount of the accelerator pedal 7 by the driver as the target opening RTA in order to set the target opening RTA of the throttle valve 4.
It corresponds to the target opening degree setting means of the present invention. This sensor 8
Is composed of, for example, a potentiometer.

The opener mechanism 11 provided at one end of the throttle shaft 9 is for holding the throttle valve 4 from the fully closed state to the opener opening slightly opened when the power supply to the motor 5 is stopped. . FIG. 2 shows a conceptual configuration of the electronic throttle 1 including the opener mechanism 11, and FIG. 3 shows the throttle valve 4 by the opener mechanism 11.
Shows the operation of.

As shown in FIG. 2, the electronic throttle 1 and its opener mechanism 11 are provided integrally with the throttle body 3. The throttle valve 4 is arranged in the bore 3a, and the throttle body 9 is centered around the throttle shaft 9.
Is rotatably supported by. The motor 5 is attached to one end of the throttle shaft 9 via the speed reducer 10 and
The throttle sensor 6 is connected to the other end of the open sensor together with the opener mechanism 11. Where the throttle valve 4
As for the opening and closing of, as shown in FIG.
The direction from the full open position F to the open position is defined as the open direction F
The direction from to the fully closed position S is referred to as the closing direction.

In FIG. 2, the opener mechanism 11 provided at the other end of the throttle shaft 9 controls the throttle valve 4 to a predetermined opener opening position N (see FIG. 3) when the motor 5 is de-energized when the engine is stopped. An opener lever 21 for holding the opener is provided. One end of a return spring 22 is connected to the opener lever 21, and the other end of the return spring 22 is fixed to the throttle body 3.
The return spring 22 biases the throttle valve 4 in the closing direction via the opener lever 21. The opener lever 21 engages with the full-open stopper 23 at a predetermined rotation position and stops. The throttle body 3 is provided with a fully closed stopper 24 for holding the throttle valve 4 in the fully closed position S (see FIG. 3). One end of an opener spring 25 is connected to the opener lever 21. The other end of the opener spring 25 is connected to the throttle shaft 9. The opener spring 25 biases the throttle valve 4 in the opening direction. These opener lever 21, return spring 22, fully open stopper 23, fully closed stopper 2
4 and opener spring 25 etc. opener mechanism 1
1 is configured.

The urging force of the return spring 22 is set to be smaller than the driving force of the motor 5 and larger than the detent torque when the motor 5 is not energized.
This setting causes the throttle valve 4 to open or close against the biasing force of the return spring 22 or the opener spring 25 when the motor 5 is energized, and when the motor 5 is not energized, the return spring 22 and the opener spring 2 are closed.
This is for holding the throttle valve 4 at a predetermined opener opening position N (see FIG. 3) by the action of 5, etc.

As shown in FIG. 3, the opener opening position N
Gives the throttle valve 4 an initial opening for securing intake air when the engine is restarted when the motor 5 is de-energized. On the other hand, when the power supply to the motor 5 is cut off during engine operation, the opener opening position N gives the throttle valve 4 an opening for maintaining the output of the engine at a necessary minimum level. As a result, the operation of the engine can be continued and the vehicle can be evacuated. As described above, when the motor 5 is not energized or when the motor 5 is de-energized, the throttle shaft 9 and the opener lever 21 are biased in the closing direction by the return spring 22. At the same time, the throttle shaft 9 is biased in the opening direction by the opener spring 25. The balance between the return spring 22 and the opener spring 25 keeps the throttle valve 4 at the opener opening position N.

Set the throttle valve 4 to the opener opening position N
In order to open from the open position F to the fully open position F, the driving force of the motor 5 is applied to the throttle shaft 9 against the urging force of the return spring 21, and the opener lever 21 is moved to the fully open stopper 23.
The throttle shaft 9 is rotated until it is engaged with. On the other hand, in order to close the throttle valve 4 from the opener opening position N to the fully closed position S, the driving force of the motor 5 is applied to the throttle shaft 9 against the biasing force of the opener spring 25, and the shaft 9 is fully closed. It is rotated until it engages with the stopper 24.

When the engine is operating, the motor 5 is controlled by the ECU 2 based on the operation of the accelerator pedal 7, so that the throttle valve 4 is opened to a predetermined target opening. At this time, the opening degree of the throttle valve 4 is determined within the operating range from the fully closed position S to the fully open position F, as shown in FIG. 3, according to the operation amount of the accelerator pedal 7. In the fully open position F, the opener lever 21
Engages with the full-open stopper 23, so that the throttle valve 4 is held with the bore 3a being opened to the maximum extent. Because of the fully open stopper 23, the throttle valve 4 does not exceed the fully open position F and excessively rotate in the opening direction. On the other hand, at the fully closed position S, since the throttle shaft 9 engages with the fully closed stopper 24, the bore 3
The throttle valve 4 is held in a state where a is maximally closed. Because of the fully closed stopper 24, the throttle valve 4 does not rotate beyond the fully closed position S in the closing direction.

As shown in FIG. 1, the ECU 2 includes a microcomputer 15, an input circuit 16, and an A / D.
It includes a converter 17 and a drive circuit 18. Microcomputer 15
Controls the electronic throttle 1 and corresponds to the control amount calculation means, the control means, and the control amount limiting means of the present invention. As is well known, the microcomputer 15 is a central processing unit (C
PU), read-write memory (RAM), read-only memory (ROM), and the like. A control program for the electronic throttle 1 is stored in the ROM. The input circuit 16 is mainly for removing noise from the output signal of the throttle sensor 6. The A / D converter 17 is for converting an analog signal into a digital signal. The drive circuit 18 is for passing a drive current according to an output signal from the microcomputer 15 to the motor 5.

In FIG. 1, an analog signal relating to the actual opening VTA output from the throttle sensor 6 passes through the input circuit 16 and is converted into a digital signal by the A / D converter 17 before being input to the microcomputer 15. Similarly, the analog signal relating to the target opening RTA output from the accelerator sensor 8 also passes through the input circuit 16 'and is converted into a digital signal by the A / D converter 17', and then the microcomputer 15
Entered in.

The microcomputer 15 controls the motor 5 by processing the input signals relating to the actual opening VTA and the target opening RTA according to the PID control method. That is, the microcomputer 15 determines from the input signal the actual opening V with respect to the target opening RTA.
The opening deviation ER of TA is calculated, and the PID control amount VPID is calculated according to a predetermined calculation formula based on the value of the opening deviation ER. Then, the microcomputer 15 controls the control amount VPID.
The duty ratio DUTY as a drive current corresponding to the value of is output to the motor 5 through the drive circuit 18. As a result, the drive amount of the motor 5 is controlled to bring the actual opening VTA of the throttle valve 4 closer to the target opening RTA.

Here, an electric circuit diagram of the input circuit 16 is shown in FIG.
Shown in. The input circuit 16 is a two-system first RC filter 3
Includes first and second RC filters 32. Each RC filter 3
1, 32 include a pair of resistors R1 and R2 and a capacitor C1. Each RC filter 31, 32 has an input terminal 3
A high resistance pull-up resistor R3 is connected between each of the power sources 3, 34 and the power supply (Vcc). Throttle sensor 6
The two signal potentiometers and the corresponding two input terminals 33 and 34 are connected by output signal lines 35 and 36, respectively. The RC filters 31 and 32 and the pull-up resistors R3 provided corresponding to the RC filters 31 and 32 are connected to the actual opening V when the two-system output from the throttle sensor 6 becomes abnormal.
It corresponds to the forcible adjustment means of the present invention for forcibly increasing the sensor output values VTA1, VTA2 of the two systems given to the microcomputer 15 as TA, corresponding to the closing direction of the throttle valve 4. In this embodiment, when the sensor output values VTA1 and VTA2 from the throttle sensor 6 that enter the RC filters 31 and 32 are interrupted by an accidental disconnection of the output signal lines 35 and 36, the RC filters 31,
The respective sensor output values VTA given to the microcomputer 15 by the respective pull-up resistors R3 provided corresponding to 32.
1, VTA2 are forcibly increased to the level of the power supply voltage Vcc corresponding to the closing direction of the throttle valve 4. Here, the reason why the throttle sensor 6 has two output values VTA1 and VTA2 is that it contributes to the output abnormality determination of the throttle sensor 6 described later.

According to the configuration of the input circuit 16, if a disconnection should occur in the middle of the output signal lines 35, 36 from the throttle sensor 6 to the input terminals 33, 34, each R will be broken.
The voltage value output from the C filters 31 and 32 to the A / D converter 17 gradually increases with a predetermined time constant, eventually reaches the power supply voltage Vcc, and the detection output is as if the throttle valve 4 were fully opened. Become. The throttle valve 4 is gradually closed in the fully closed direction by the feedback control of the motor 5 by the microcomputer 15 based on the comparison between this output signal and the signal related to the target opening RTA. That is, the throttle valve 4 always operates toward the fully closed direction, which is the safe side, and an abnormal increase in engine output is suppressed.

Here, the microcomputer 15 controls each output signal line 3
When the wires 5 and 36 are disconnected, the motor 5 is driven in the direction in which the change in the signal output from the input circuit 16 is canceled, and the throttle valve 4 is operated in the fully closed direction. However, if the throttle valve 4 is actually operated to the fully closed position S, in the worst case, the throttle valve 4 will hit the fully closed stopper 24 at the fastest operation, and damage to the speed reducer 10 of the throttle valve 4 will be caused. Is big. In particular, the damage given to each resin gear 12 may be large. Further, when the throttle valve 4 is suddenly fully closed, the operation of the automobile engine is rapidly decelerated, the drivability thereof is deteriorated, and the engine may stall in the worst case. Therefore, in this embodiment, the electronic throttle 1 is controlled so as to avoid the above-mentioned problem when the throttle sensor 6 is disconnected.

Next, the control contents of the electronic throttle 1 will be described in detail. FIG. 5 is a flowchart showing a throttle control program executed by the ECU 2 (hereinafter, described as the microcomputer 15). FIG. 6 is a flowchart showing an output abnormality determination program for the throttle sensor 6 executed by the microcomputer 15. The microcomputer 15
These routines are periodically executed every predetermined time.

First, when the processing shifts to the routine of the throttle control program shown in FIG. 5, at step 100,
The microcomputer 15 calculates the value of the opening deviation ER between the target opening RTA set by the detection of the accelerator sensor 8 and the actual opening VTA detected by the throttle sensor 6.

In step 101, the microcomputer 15 calculates the value of the proportional term VP by multiplying the value of the predetermined proportional gain KP by the value of the opening deviation ER calculated this time.

In step 102, the microcomputer 15 adds the product of the value of the predetermined integral gain KI and the value of the opening deviation ER calculated this time to the integrated value up to the previous time to determine the value of the integral term VI. calculate.

At step 103, the microcomputer 15 calculates the value of the differential term VD by multiplying the differential value of the value of the opening deviation ER calculated this time by the value of a predetermined differential gain Kd.

Then, in step 104, the microcomputer 15
Calculates the value of the PID control amount VPID by adding the value of the proportional term VP calculated this time, the value of the integral term VI, and the value of the differential term VD. In this embodiment, the microcomputer 15 that executes the processing of steps 100 to 104
Corresponds to the control amount calculation means of the present invention.

At step 105, the microcomputer 15 converts the value of the PID control amount VPID calculated this time into the value of the duty ratio DUTY by a predetermined functional expression.

In step 106, the microcomputer 15 calculates the absolute value of the difference between the current target opening RTA value and the previous target opening RTAO value as the target opening change amount DLR.

Then, in step 107, the microcomputer 15
Determines whether the value of the target opening change amount DLR is less than or equal to a predetermined value L1. If the result of this determination is negative, it is determined that the value of the target opening RTA has changed to some extent, and the microcomputer 15 shifts the processing to step 112.
Then, in step 112, the microcomputer 15 clears the value of the predetermined timer TZ and shifts the processing to step 113. On the other hand, if the determination result in step 107 is affirmative, the microcomputer 15 determines that the value of the target opening RTA has hardly changed, and the microcomputer 15 shifts the processing to step 108.

At step 108, the microcomputer 15 determines whether or not the value of the timer TZ is greater than or equal to the predetermined value T1.
That is, the microcomputer 15 determines whether or not the target opening degree change amount DLR is below the predetermined value L1 to some extent. If the result of this determination is negative, the microcomputer 15 proceeds directly to step 111. If this determination result is affirmative, the microcomputer 15 executes the process in step 1.
Move to 09.

At step 109, the microcomputer 15 determines whether or not the value of the duty ratio DUTY calculated this time is equal to or larger than a predetermined guard value G1. Here, the guard value G
1 is a predetermined value other than the maximum value and the minimum value of the duty ratio DUTY and is a value that can suppress the operating speed of the throttle valve 4 to a low value, for example, a value that can be suppressed to a speed that is ½ or less of the speed at the maximum speed operation. Can be used. If the result of the determination is negative, the microcomputer 15 proceeds directly to step 111. If the determination result is affirmative, the microcomputer 15 changes the duty ratio DUTY to the guard value G1 in step 110, and the process proceeds to step 1
Go to 11. That is, in steps 109 and 110,
The microcomputer 15 sets the duty ratio DUTY to the guard value G1.
It is limited by.

Then, step 108 and step 109
Alternatively, the process proceeds from step 110 to step 111,
The microcomputer 15 increments the value of the timer TZ. That is, the microcomputer 15 measures the duration time when the target opening change amount DLR becomes equal to or less than the predetermined value L1.

When there is no change in the value given to the microcomputer 15 as the target opening RTA, the microcomputer 15 which executes the processing of steps 107 to 112 calculates the duty ratio DUTY and determines the maximum value of the duty ratio DUTY. It corresponds to the control amount limiting means of the present invention for limiting the guard value G1 other than the minimum value.

Then, step 111 or step 11
In step 113 after shifting from 2, the microcomputer 15
The fail flag FAIL of the throttle sensor 6 is "1".
It is determined whether or not there is an output abnormality of the throttle sensor 6. The fail flag FAIL is set by a determination made by the microcomputer 15 in a separate routine described later. This fail flag FAIL
Is set to "1" at the time of abnormality determination and "0" at the time of normality determination. When the above determination result is negative, the microcomputer 15 directly shifts the processing to step 115. If the determination result is affirmative, the microcomputer 15 sets the duty ratio DUTY to “0” in step 114 in order to stop energization of the motor 5.

Then, step 113 or step 11
In step 115 after shifting from 4, the microcomputer 15
Based on the value of the duty ratio DUTY calculated or set this time, the motor 5 is controlled via the drive circuit 18, and the process is temporarily terminated until the next control cycle comes.

Next, the output abnormality determining program for the throttle sensor 6 will be described with reference to the flowchart of FIG. In this embodiment, the output abnormality determination is individually performed for the output values VTA1 and VTA2 of the two systems from the throttle sensor 6, but in this flowchart, those output values VTA1 and VTA2 are referred to as “actual opening VT”.
A ”will be commonly described.

When the processing shifts to the routine of FIG. 6, in step 150, the microcomputer 15 determines whether or not the value of the actual opening VTA detected by the throttle sensor 6 is a predetermined determination value L3 or more. . Here, the predetermined determination value L3
Is close to the value of the power supply voltage Vcc and is set to a value slightly smaller than that. If the result of this determination is negative, the microcomputer 15 clears the abnormality determination counter TF in step 154, and temporarily ends the subsequent processing. If the determination result is affirmative, the microcomputer 15 shifts the processing to step 151.

At step 151, the microcomputer 15 determines whether or not the value of the abnormality determination counter TF is equal to or greater than a predetermined determination value T3. Here, when the abnormality determination counter TF is equal to or greater than the determination value T3, the output abnormality of the throttle sensor 6 is definitely determined. Therefore, step 1
If the determination result in 51 is negative, it is determined that the output abnormality has not been definitely determined, and the microcomputer 15 directly proceeds to step 153. If the determination result is affirmative, it is determined that the output abnormality is definitely determined, and the microcomputer 15 sets the fail flag FAIL to “1” in step 152 and shifts the processing to step 153.

Then, step 151 or step 15
In step 153 after shifting from 2, the microcomputer 15
The abnormality determination counter TF is incremented and the subsequent processing is temporarily ended.

According to the electronic throttle control apparatus of this embodiment described above, the value of the target opening RTA set by the accelerator sensor 8 and the value of the actual opening VTA detected and output by the throttle sensor 6 are set. Are given to the microcomputer 15, respectively. Further, based on the value of the opening deviation ER between the target opening RTA and the actual opening VTA, the microcomputer 1
5, the value of the duty ratio DUTY of the motor 5 is calculated. Then, based on the value of the duty ratio DUTY, the microcomputer 15 feedback-controls the motor 5, whereby the actual opening VTA of the throttle valve 4 is increased.
Becomes closer to the target opening RTA.

If one of the two output signal lines 35 and 36 of the throttle sensor 6 is disconnected and one of the sensor output values VTA1 and VTA2 becomes an abnormal value (zero),
Two-system sensor output value VTA given to the microcomputer 15
One of V1 and VTA2 is forcibly increased to the level of the power supply voltage Vcc by the corresponding pull-up resistor R3 in the closing direction of the throttle valve 4. As a result, the value of the duty ratio DUTY calculated by the microcomputer 15 decreases toward its minimum value, and the actual opening VTA of the throttle valve 4 operates toward the fully closed state on the safe side.

At this time, although the one of the two sensor output values VTA1 and VTA2 from the throttle sensor 6 is changing, the microcomputer 15 sets the target opening RTA.
If there is no change in the value given to, the calculation of the duty ratio DUTY by the microcomputer 15
It is limited to the guard value G1 other than the maximum value and the minimum value of TY. Therefore, the throttle valve 4 has its actual opening VTA.
The operating speed of the vehicle toward the fully closed position S is moderated. As a result, the operation of the throttle valve 4 due to an abnormal output when the output signal lines 35, 36 of the throttle sensor 6 should be disconnected can be alleviated, and the throttle valve 4 may hit the fully closed stopper 35 at the fastest operation. Therefore, it is possible to prevent the damage to the reduction gear transmission 10 that is interlocked with the throttle valve 4. Further, the damage does not cause a new malfunction of the throttle valve 4. Further, in the automobile engine, the driving does not suddenly decelerate when the output is abnormal, deterioration of drivability can be suppressed, and the occurrence of engine stall can be prevented.

FIG. 7 shows an example of the sensor output and the behavior of the throttle opening according to the present embodiment and the prior art in the coping operation when the output is abnormal. Here, the "sensor output" corresponds to each sensor output value VTA1, VTA2 of the throttle sensor 6 in the above description, and the "throttle opening" means the actual opening of the throttle sensor 6 in the above description. .

In FIG. 7, if one of the output signal lines 35 and 36 of the throttle sensor 6 is disconnected at time t0, the RC filters 31 and 32 of the input circuit 16 will be subject to the characteristics and the subsequent time t3. The sensor output increases to the power supply voltage Vcc. During this period, the sensor output is at the time t2 and the determination level (determination value L that is close to the power supply voltage Vcc).
2) is reached, and the output abnormality of the throttle sensor 6 is determined between time t2 and time t3. When the determination of the output abnormality is confirmed at time t3, the energization of the motor 5 is stopped as a measure. Therefore, the throttle valve 4 is held at the opener opening position N by the opener mechanism 11.

In this embodiment, the throttle sensor 6
Since the output abnormality is determined at a determination level close to the power supply voltage Vcc, it tends to take some time from the occurrence of the output abnormality to the completion of the determination, during which the motor 5 is driven to some extent. Therefore, in the device of the related art, as shown by the broken line in FIG. 7, the throttle valve has already reached the fully closed position and hits the fully closed stopper at time t1 before the start of the output abnormality determination. Become.
On the other hand, according to the device of the present embodiment, if the target opening does not change, even if the duty ratio DUTY changes to a value in the closing direction, the change is guarded. Therefore, as is clear from the solid line shown in FIG. 7, the operation of the motor 5 that drives the throttle valve 4 to close is moderated, and the fastest operation of the throttle valve 4 is suppressed by time t3 when the determination of the abnormal output is completed. It can be seen that the throttle opening degree changes relatively slowly and returns to the opener opening degree before reaching the fully closed position.

[Second Embodiment] A second embodiment in which the electronic throttle control device of the present invention is embodied in an automobile engine will be described below in detail with reference to the drawings.

In each of the following embodiments including this embodiment, the same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. I will mainly explain the points.

This embodiment differs from the first embodiment in the contents of the throttle control program and the output abnormality determination program executed by the microcomputer 15. That is, regarding the abnormality determination program, in this embodiment, a case where the sensor output values VTA1 and VTA2 change rapidly (case in which the value of the pull-up resistor R3 is relatively small)
, The judgment value L3 of step 150 in FIG.
Is a judgment value L2 which is obviously smaller than the value of the power supply voltage Vcc.
Is set to. In this embodiment, the microcomputer 15 that executes such an abnormality determination program corresponds to the output abnormality determination means of the present invention for deterministically determining the output abnormality of the throttle sensor 6 over a predetermined time.

Next, the output abnormality determination program for the throttle sensor 6 will be described with reference to the flowchart of FIG.

When the processing shifts to the routine of FIG. 8, the microcomputer 15 causes the A / D converter 17 to operate in step 200.
As the output signal from the sensor A / D value of the first system (first
First, the converted value of the analog signal from the RC filter 31
It is taken in as the sensor output value VTA1.

At step 201, the microcomputer 15 sets A /
As the output signal from the D converter 17, the sensor A / D value of the second system (the converted value of the analog signal from the second RC filter 32) is taken in as the second sensor output value VTA2.

At step 202, the microcomputer 15 executes the first
The absolute value of the difference between the sensor output value VTA1 and the second sensor output value VTA2 is calculated as the sensor output difference VT12.

In step 203, the microcomputer 15 determines that the value of the sensor output difference VT12 calculated this time is the predetermined judgment value L.
Judge whether it is 2 or more. In this embodiment, the determination value L2 is set to a value that is close to zero and slightly larger than zero. Here, assuming that the two systems of potentiometers of the throttle sensor 6 have the same characteristics, the determination value L2 is set to a value slightly larger than zero in consideration of their characteristic tolerances. If the result of this determination is negative, it is assumed that both sensor output values VTA1 and VTA2 are substantially equal and there is no abnormality in the output of the throttle sensor 6, and that there is no failure such as disconnection in each output signal line 35, 36. In step 207, the microcomputer 15 clears the abnormality determination counter TF and shifts the processing to step 208. If this determination result is affirmative, the sensor output values VTA1 and VTA2 are different, and the throttle sensor 6
Output, or the output signal lines 35 and 36 have an output abnormality such as disconnection, and the process proceeds to step 204.

At step 204, the microcomputer 15 determines whether or not the value of the abnormality determination counter TF is greater than or equal to a predetermined determination value T3. Here, when the abnormality determination counter TF is equal to or greater than the determination value T3, the output abnormality of the throttle sensor 6 is definitely determined. Therefore, step 2
If the determination result in 04 is negative, it is determined that the output abnormality is not definitely determined, and the microcomputer 15 shifts the processing to step 206. If the determination result is affirmative, it is determined that the output abnormality is definitely determined, and the microcomputer 15 determines in step 205 that the fail flag FAIL.
Is set to "1" and the process proceeds to step 206.

Then, step 204 or step 20.
In step 206 after shifting from 5, the microcomputer 15 increments the abnormality determination counter TF.

Then, step 206 or step 20
7, the microcomputer 15 sets the first sensor output value VTA1 as the value of the actual opening VTA in step 208, and temporarily ends the subsequent processing.

That is, in this embodiment, it is found that the difference between the outputs of the two systems from the throttle sensor 6 is greater than or equal to a predetermined value, and if that state continues for a predetermined time, the throttle sensor 6 has an abnormal output. Is determined.

Next, the processing contents of the throttle control program executed by the microcomputer 15 will be described with reference to the flowchart of FIG. The flowchart of FIG. 9 differs from the flowchart of FIG. 5 in that steps 107 to 112 in the flowchart of FIG. 5 are replaced with steps 120 to 122.

That is, in the flowchart of FIG. 9, when the target opening change amount DLR is calculated in step 106, the microcomputer 15 determines in step 120 that the abnormality determination counter T
It is determined whether the value of F is greater than or equal to a predetermined determination value T2. This abnormality determination counter TF is counted by a separate routine relating to the above-described output abnormality determination program, and the determination value T2 is shorter than the total time (determination value T3) required for definite determination at that time. Equivalent to time. If the determination result is negative, the microcomputer 15
The process directly shifts to step 113. If the determination result is affirmative, the microcomputer 15 shifts the processing to step 121.

At step 121, the microcomputer 15 determines whether or not the value of the duty ratio DUTY calculated this time is equal to or larger than a predetermined guard value G1. If the result of this determination is negative, the microcomputer 15 proceeds directly to step 113. If the determination result is affirmative, the microcomputer 15 determines in step 122 the duty ratio DUT.
Y is set to the guard value G1, and the process proceeds to step 113. That is, in steps 121 and 122, the microcomputer 15 limits the duty ratio DUTY to the guard value G1.

Here, the microcomputer 15 which executes the processing of steps 120 to 122 performs control when the microcomputer 15 observes a sign of an output abnormality of the throttle sensor 6 and before the output abnormality is definitely determined. It corresponds to the control amount limiting means of the present invention for limiting the calculation of the duty ratio DUTY which is the amount to the guard value G1 as a predetermined value other than the maximum value and the minimum value of the duty ratio DUTY.

Then, in steps 113 to 115, the microcomputer 15 does not stop the motor 5 unless the fail flag FAIL becomes "1" (unless an output abnormality is determined), as described with reference to FIG. The motor 5 is controlled based on the duty ratio DUTY calculated this time to drive the throttle valve 4.

The operation and effects of the electronic throttle control device of this embodiment described above are as follows. That is,
In the unlikely event that a disconnection occurs in one of the two output signal lines 35, 36 of the throttle sensor 6, each sensor output value VTA1, VTA
When one of TA2 becomes an abnormal value (zero), one of the two sensor output values VTA1 and VTA2 provided to the microcomputer 15 corresponds to the closing direction of the throttle valve 4 by the corresponding pull-up resistor R3. It is forcibly increased to the level of power supply voltage Vcc. As a result, the value of the duty ratio DUTY calculated by the microcomputer 15 decreases toward its minimum value, and the actual opening VTA of the throttle valve 4 operates toward the fully closed state on the safe side.

At this time, the output abnormality of the throttle sensor 6 is deterministically determined by the microcomputer 15 over a predetermined time. If the microcomputer 15 observes an indication of the output abnormality, the output abnormality is deterministically determined. Calculation of the duty ratio DUTY before
Are limited to the guard value G1 other than the maximum value and the minimum value of.
Therefore, the operation of the throttle valve 4 in the closing direction stops before the actual opening VTA reaches the fully closed position S, and the operation speed when the throttle valve 4 stops is moderated.
As a result, similarly to the case of the first embodiment, the operation of the throttle valve 4 due to an abnormal output when the output signal lines 35 and 36 of the throttle sensor 6 should be disconnected can be alleviated, and the throttle valve 4 can be operated. It is possible to prevent the full-closed stopper 35 from hitting at the fastest operation, and suppress damage to the reduction gear transmission 10 that interlocks with the throttle valve 4. Further, the damage does not cause a new malfunction of the throttle valve 4. Further, in the automobile engine, the driving does not suddenly decelerate when the output is abnormal, deterioration of drivability can be suppressed, and the occurrence of engine stall can be prevented.

Further, in this embodiment, the output abnormality of the throttle sensor 6 is detected by the sensor output value VTA of two systems.
This is detected by calculating the difference between 1 and VTA2. Therefore, when one of the output signal lines 35 and 36 relating to the two output values VTA1 and VTA2 is disconnected, the two output values are output before the signal output on the disconnected side reaches the level of the power supply voltage Vcc. The abnormality detection can be started when a predetermined difference occurs between VTA1 and VTA2.

FIG. 10 shows an example of the sensor output in the above-mentioned operation for coping with an abnormal output and the behavior of the throttle opening according to the present embodiment and the prior art. In FIG.
At time t0, each output signal line 35 of the throttle sensor 6,
Should one of the lines 36 be disconnected, the subsequent sensor output rapidly increases toward the power supply voltage Vcc according to the characteristics of the RC filters 31 and 32 of the input circuit 16. During this period, the sensor output has already reached the determination level (determination value L2) at time t1 immediately after the occurrence of the abnormality, and a sign of output abnormality is observed during the determination time 1 up to time t2. And
When the predetermined determination time 2 has elapsed from the time t1 and the output abnormality is definitely determined at the time t3, the motor 5 is taken as a measure.
Energization is stopped. Therefore, the throttle valve 4 is held at the opener opening position N by the opener mechanism 11.

In this embodiment, the throttle sensor 6
There is a tendency that it takes some time until the output abnormality is determined definitely, and the motor 5 is driven to some extent during that time. Therefore, in the conventional device, as shown by the broken line in FIG. 10, the throttle valve reaches the fully closed position before the time t3 at which the output abnormality is definitely determined and hits the fully closed stopper. Become. On the other hand, according to the device of the present embodiment, the change in the duty ratio DUTY is guarded before the output abnormality is definitely determined, that is, from the time when the sign of the output abnormality is observed. . Therefore, also in this embodiment, as is clear from the solid line shown in FIG. 10, the operation of the motor 5 for closing and driving the throttle valve 4 is alleviated, and the throttle valve 4 is closed by time t3 when the determination of the abnormal output is completed. It can be seen that the maximum speed operation is suppressed, the throttle opening changes relatively slowly, and returns to the opener opening before reaching full closure.

The present invention is not limited to the above-mentioned embodiments, but can be carried out as follows within the scope of the invention.

(1) In each of the above-described embodiments, the procedure for the output abnormality described in steps 107 to 112 of the flowchart of FIG. 5 and step 120 of the flowchart of FIG.
Although the procedure described in each of steps 122 to 122 has been described separately, these procedures may be executed in parallel.

(2) In each of the above-mentioned embodiments, disconnection of the output signal lines 35 and 36 is mentioned as the output abnormality of the throttle sensor 6, but in the case of disconnection of the power supply line or GND line to the throttle sensor 6 Can also be mentioned as Here, in the case of power line disconnection,
Both sensor output values VTA1 and VTA2 of the two systems are GN
It can be determined that the output is abnormal when the level changes to the D level. On the other hand, in the case of the GND line disconnection, it can be determined as an output abnormality when both the sensor output values VTA1 and VTA2 of the two systems change to the power supply voltage Vcc level.

(3) In each of the above-described embodiments, the determination of the output abnormality of the throttle sensor 6 is made by determining the sensor output value VT of two systems.
This was done by comparing A1 and VTA2. On the other hand, the throttle sensor may make a determination when it detects an output voltage that is not possible under normal conditions, or may make a determination when it detects that the speed of change in the output of the throttle sensor changes at a speed that is normally not possible. .

(4) In each of the above embodiments, the electronic throttle control device of the present invention is embodied in a single throttle type in which one throttle valve is arranged in the intake passage,
In the case where the output of the throttle sensor is abnormal, the case where the throttle valve is driven in the fully closed direction as the safe side has been described. On the other hand, in the electronic throttle control device of the present invention, two throttle valves (main throttle valve and sub-throttle valve) are arranged in series in the intake passage, and the main throttle valve is linked to the accelerator pedal via the accelerator wire. Alternatively, the sub-throttle valve may be embodied as a tandem throttle type that is constituted by the electronic throttle of the present invention and is normally biased by a return spring so as to be fully opened. Then, when the output of the throttle sensor is abnormal, the sub-throttle valve may be configured to be driven in the fully open direction as a safe side. Therefore, in this case, when the output of the throttle sensor becomes abnormal, the value given to the microcomputer as the actual opening is forcibly reduced according to the opening direction of the throttle valve.

[0082]

According to the configuration of the invention described in claim 1,
The fastest operation of the throttle valve due to abnormal output when the throttle sensor fails can be mitigated, and damage to the drive system of the throttle valve can be suppressed.

According to the second aspect of the invention, similarly, the fastest operation of the throttle valve due to an abnormal output when the throttle sensor fails can be mitigated, and damage to the drive system of the throttle valve can be suppressed. .

[Brief description of drawings]

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

FIG. 2 is a conceptual configuration diagram showing an electronic throttle.

FIG. 3 is an explanatory diagram showing an operation of a throttle valve by an opener mechanism.

FIG. 4 is an electric circuit diagram showing the configuration of an input circuit in detail.

FIG. 5 is a flowchart showing a throttle control program.

FIG. 6 is a flowchart showing an output abnormality determination program.

FIG. 7 is a time chart showing an example of behavior of sensor output and throttle opening.

FIG. 8 is a flowchart showing an output abnormality determination program according to the second embodiment.

FIG. 9 is a flowchart showing a throttle control program.

FIG. 10 is a time chart showing an example of behaviors of sensor output and throttle opening.

FIG. 11 is an electric circuit diagram showing a conventional control device.

[Explanation of symbols]

1 electronic throttle 2 ECU 4 Throttle valve 5 Motor (actuator) 6 Throttle sensor (actual opening detection means) 8 Accelerator sensor (Target opening setting means) 15 Microcomputer 16 input circuits 31 1st RC filter 32 2nd RC filter 35 Output signal line 36 Output signal line R3 pull-up resistance (forced adjustment means)

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3G065 CA39 DA04 FA08 FA11 FA14                       GA41 GA46 KA04 KA15 KA16                       KA22 KA36                 3G084 BA05 DA30 EB11 FA10                 3G301 JB01 LA01 LC03 ND01 ND41                       ND42 PA11A PA11Z PF03Z

Claims (2)

[Claims] 1. An electronic throttle for driving a throttle valve to open and close by an actuator, target opening setting means for setting a target opening of the electronic throttle, and for detecting and outputting an actual opening of the electronic throttle. Actual opening detection means, control amount calculation means for calculating the control amount of the actuator based on the opening deviation between the target opening and the actual opening, and feedback control of the actuator based on the control amount. When the output of the actual opening detection means is abnormal, the value given to the control amount calculation means as the actual opening is forced in the direction in which the throttle valve operates toward the safe side. In an electronic throttle control device including a forced adjustment means for increasing or decreasing, the control amount calculation means is provided with the target opening degree. An electronic throttle control device comprising control amount limiting means for limiting the calculation of the control amount to a predetermined value other than the maximum value and the minimum value of the control amount when there is no change in the obtained value. 2. An electronic throttle for opening and closing a throttle valve by an actuator, a target opening setting means for setting a target opening of the electronic throttle, and an actual opening of the electronic throttle for detection and output. Actual opening detection means, control amount calculation means for calculating the control amount of the actuator based on the opening deviation between the target opening and the actual opening, and feedback control of the actuator based on the control amount. When the output of the actual opening detection means is abnormal, the value given to the control amount calculation means as the actual opening is forced in the direction in which the throttle valve operates toward the safe side. In an electronic throttle control device provided with a forced adjustment means for increasing or decreasing the output abnormality of the actual opening detection means for a predetermined time. Output abnormality determination means for deterministically determining the output abnormality, when a sign of the output abnormality is observed by the output abnormality determination means, before the output abnormality is definitely determined, calculation of the control amount Control unit for limiting the control amount to a predetermined value other than the maximum value and the minimum value of the control amount.