JP2000240491A - Electronic throttle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize the power consumption in normal time and stop the current-carrying to a throttle actuator when a microcomputer is abnormal by providing a logic circuit for generating a logic sum of the control signal of the microcomputer and the detection signal of a monitoring microcomputer and outputting the result to a drive circuit. SOLUTION: An electronic throttle control microcomputer 3 generates a plurality of control signals S1-S4 for controlling a drive circuit 2 according to the operating state of an internal combustion engine. A monitoring microcomputer 4 detects the abnormality of a system and outputs the detection signal to a logic circuit 5. The logic circuit 5 has a plurality of AND circuits A1-A4, and controls the control signals S1-S4 according to the detection signal. The logic circuit 5 normally transmits the control signals S1-S4 to the drive circuit 2 as they are, and it takes the logic sum of the control signals S1-S4 with the signal from the monitoring microcomputer 4, in the event of the abnormality of the system, and changes the level of the control signals S1-S4 to LOW to stop the operation of a motor 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electronic throttle control device that does not energize a throttle actuator when a control microcomputer is abnormal.

[0002]

2. Description of the Related Art Japanese Patent Laying-Open No. 7-4294 discloses an electronic throttle control device which does not supply current to a DC motor when an abnormality related to throttle control is detected. FIG. 2 is a diagram showing such an electronic throttle control device.

An electronic throttle control device 20 shown in FIG.
Is a motor 1, a power cut circuit 21, an electronic throttle control microcomputer 23, a monitoring microcomputer 24, a transistor T
It is equipped with a ₁ ~T _4.

The electronic throttle control microcomputer 23 controls the motor 1 by turning on or off the transistors T _{1 to} T ₄ . When detecting an abnormality relating throttle control, monitoring microcomputer 24 controls the power supply cutting circuit 21 so that no current flows through the transistor T ₁ through T _4.

[0005]

When the throttle control is normal, a current necessary for driving the motor 1 flows through the power supply cutoff circuit 21. In other words, a large amount of power is consumed by the power supply cut circuit 21. For example, the potential difference between the terminal 21a of the power cut circuit 21 and the terminal 21b of the power cut circuit 21 is 0.3V to 0.4V,
The current flowing between the terminal 21a and the terminal 21b is 2A to 3A.
In the case of A, the power cutoff circuit 21 consumes about 1 W of power. That is, the power supply cut circuit 21
There is a problem that about 1 W of power is wasted.

The power consumed by the power supply cut circuit 21 becomes heat. In order for the power cut circuit 21 to operate normally,
It is necessary to release the generated heat into the air. In order to release the heat into the air, for example, a heat sink (not shown) is provided in the power supply cutoff circuit 21. When a heat sink is provided in the power supply cut circuit 21, there is a problem that the size of the electronic throttle control device becomes large. Also,
When a heat sink is installed in the electronic throttle control device, there is a problem that the cost for the heat sink increases.

[0007] In view of the above problems, the present invention provides an electronic throttle control device which does not energize the throttle actuator when the control microcomputer is normal and consumes low power, and when the control microcomputer is abnormal. The purpose is to:

[0008]

SUMMARY OF THE INVENTION An electronic throttle control device according to the present invention controls a throttle actuator for opening and closing a throttle valve of an internal combustion engine, a drive circuit for controlling energization of the throttle actuator, and controlling an opening of the throttle valve. A control microcomputer for generating a control signal, a monitoring microcomputer for detecting a system abnormality and outputting a detection signal, and generating a logical product of the control signal and the detection signal, and driving a signal as a result thereof A logic circuit for outputting to the circuit, wherein the drive circuit controls energization of the throttle actuator in accordance with an output signal from the logic circuit, thereby achieving the above object.

[0009]

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

FIG. 1 is a diagram showing an embodiment of an electronic throttle control device of the present invention.

An electronic throttle control device 10 shown in FIG.
Includes a motor 1, a drive circuit 2, an electronic throttle control microcomputer 3, a monitoring microcomputer 4, and a logic circuit 5.

The motor 1 operates as a throttle actuator for opening and closing a throttle valve of the internal combustion engine.

The driving circuit 2 includes a plurality of transistors T ₁ to T ₁ .
It has a T _4. When the plurality of transistors T _{1 to} T ₄ are turned on or off, the motor 1 is energized. The configuration of the drive circuit 2 is not limited to a transistor, and may be any switching element that can control the motor 1. For example, the drive circuit 2 may have a thyristor instead of a transistor.

The electronic throttle control microcomputer 3 generates a plurality of control signals S _{1 to} S ₄ for controlling the drive circuit 2 according to the operation state of the internal combustion engine. The operating state of the internal combustion engine may be, for example, an accelerator opening at which an operator operating the internal combustion engine depresses the accelerator. In that case, the electronic throttle control microcomputer 3 may generate a plurality of control signals S _{1 to} S ₄ according to the signal indicating the accelerator opening.
The plurality of control signals S _{1 to} S ₄ are sent to the logic circuit 5 for fail-safe.

The monitoring microcomputer 4 detects an abnormality in the system and outputs a detection signal to the logic circuit 5. For example, when the system is abnormal, the monitoring microcomputer 4 outputs a low-level detection signal to the logic circuit 5, and when the system is not abnormal, the monitoring microcomputer 4 outputs a high-level detection signal to the logic circuit 5.

The logic circuit 5 includes a plurality of AND circuits A _{1 to} A ₄
have. The logic circuit 5 controls a plurality of control signals S _{1 to} S ₄ according to the detection signal. For example, logic circuit 5
Calculates the logical product of each of the plurality of control signals S _{1 to} S ₄ and the detection signal, and outputs the resulting plurality of signals to the driving circuit 2.
Output to

An example of the operation of the electronic throttle control device 10 when no system abnormality has occurred will be described below.

The monitoring microcomputer 4 outputs a high-level signal to the logic circuit 5 because no abnormality has occurred in the system. Further, the electronic throttle control microcomputer 3 outputs a plurality of control signals S _{1 to} S ₄ to the logic circuit 5 according to the operation state of the internal combustion engine. Note that the plurality of control signals S _{1 to} S ₄ correspond to the plurality of transistors T _{1 to} T ₄ in the drive circuit 2, respectively.

The logic circuit 5 includes a plurality of control signals S₁~ S_Fourof
The logical product of each and the signal from the monitoring microcomputer 4 is calculated.
You. Since no system error has occurred, multiple control signals
No. S ₁~ S_FourThe level of the
Control signal S₁~ S_FourIs sent to the drive circuit 2. Control signal S₁
~ S_FourThe drive circuit 2 is controlled by the motor, and the motor 1 operates
I do. As a result, the opening of the throttle valve is
It changes according to the operating state of the fuel engine.

An example of the operation of the electronic throttle control device 10 when a system abnormality has occurred will be described below.

The monitoring microcomputer 4 outputs a low-level signal to the logic circuit 5 because a system abnormality has occurred. Further, the electronic throttle control microcomputer 3 outputs a plurality of control signals S _{1 to} S ₄ to the drive circuit 2.

The logic circuit 5 calculates the logical product of each of the plurality of control signals S _{1 to} S ₄ and the signal from the monitoring microcomputer 4. Since a system abnormality has occurred, the levels of the plurality of control signals S _{1 to} S ₄ are changed to low. Therefore, the motor 1 does not operate due to the control signals S _{1 to} S ₄ .

As described above, the electronic throttle control device 10 can stop the operation of the motor 1 when a system abnormality has occurred. Therefore, the electronic throttle control device 10 can close the throttle valve when a system abnormality has occurred. As a result, failsafe of the internal combustion engine is maintained.

The above-mentioned system abnormality includes at least one of the following cases (1) to (3).

(1) When the difference between the accelerator opening when the operator depresses the accelerator and the actual throttle valve opening is not within a predetermined threshold value. For example, the monitoring microcomputer 4 receives a signal from a sensor for measuring the accelerator opening and a signal from a sensor for measuring the opening of the throttle valve, and the monitoring microcomputer 4 compares the signals to thereby provide a system. An abnormality is detected.

(2) When the electronic throttle control microcomputer 3 is abnormal. For example, the monitoring microcomputer 4 performs a watchdog on the electronic throttle control microcomputer 3 to detect an abnormality of the electronic throttle control microcomputer 3.

(3) When the sensor is abnormal (3-1) When the sensor for measuring the opening of the throttle valve is a double system and the difference between the signals output from the respective sensors is not within a predetermined threshold value . For example, the monitoring microcomputer 4 receives signals output from the respective sensors, and the monitoring microcomputer 4 compares the signals to detect an abnormality of the dual sensor that measures the opening of the throttle valve. .

(3-2) The case where the sensor for measuring the accelerator opening when the operator steps on the accelerator is a dual system, and the difference between the signals output from the sensors is not within a predetermined threshold. For example, the monitoring microcomputer 4 receives signals output from the respective sensors, and the monitoring microcomputer 4 compares the signals to detect an abnormality in the sensor that measures the accelerator opening of the dual system.

(3-3) At least one of a sensor for measuring the opening of the throttle valve and a sensor for measuring the accelerator opening when the operator steps on the accelerator.
If one is broken or shorted. For example, the monitoring microcomputer 4 receives a signal output from the sensor,
If the value of the signal is not within the predetermined range, an abnormality of the sensor is detected.

The electronic throttle control device 10 described above
If a system malfunction occurs, the transistor T₁~ T_FourTo
By turning off, the operation of the motor 1 was stopped. I
However, to stop the operation of the motor 1,
Transistor T₁~ T_FourNo need to turn off. Was
For example, if the logic circuit 5 is an AND circuit A₁And A_FourOnly have
Even if the system is
If the system malfunctions, the operation of the motor 1 must be stopped.
Can be. The logic circuit 5 is an AND circuit A. _Twoand
A_ThreeEven if it has only
Therefore, when a system abnormality occurs, the operation of the motor 1 is stopped.
Can be stopped.

That is, even when the logic circuit 5 of the present embodiment has two AND circuits, the operation of the motor 1 can be stopped when a system abnormality occurs. In this case, since the number of components of the logic circuit 5 is small, the electronic throttle control device can be provided at low cost.

The electronic throttle control device generates a throttle actuator for opening and closing the throttle valve of the internal combustion engine, a drive circuit for controlling the energization of the throttle actuator, and a control signal for controlling the opening of the throttle valve. A control microcomputer, a monitoring microcomputer that detects a system abnormality and outputs a detection signal, and a logic circuit that generates a logical product of the control signal and the detection signal and outputs a signal that is the result to a drive circuit. When the electronic throttle control device is provided, the configuration of the electronic throttle control device may be as follows.

[0033] The drive circuit may include a plurality of switching elements. Further, the drive circuit may include four or more switching elements.

The control microcomputer, the monitoring microcomputer and the logic circuit may be formed on the same chip.

[0035] The logic circuit may include a plurality of AND circuits. Further, the logic circuit may include two AND circuits. The logic circuit may include four AND circuits.

[0036]

The electronic throttle control device according to the present invention comprises a throttle actuator for opening and closing a throttle valve of an internal combustion engine, a drive circuit for controlling the energization of the throttle actuator, and a control signal for controlling the opening of the throttle valve. And a monitoring microcomputer that detects a system abnormality and outputs a detection signal, generates an AND of the control signal and the detection signal, and outputs a signal that is the result to the drive circuit. A logic circuit. The drive circuit controls energization of the throttle actuator according to an output signal from the logic circuit.

No current for driving the throttle actuator flows through the logic circuit. For this reason,
The power consumed by the logic circuit is smaller than that of a conventional electronic throttle control device.

The heat released from the logic circuit is
Smaller than a conventional electronic throttle control device. Therefore, the logic circuit of the electronic throttle control device of the present invention does not require a member such as a heat sink. As a result, the electronic throttle control device of the present invention can be provided at a lower cost than the conventional electronic throttle control device. Further, the electronic throttle control device of the present invention does not require a power supply cutoff circuit.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of an electronic throttle control device of the present invention.

FIG. 2 is a diagram showing a conventional electronic throttle control device.

[Explanation of symbols]

 1 motor 2 drive circuit 3 electronic throttle control microcomputer 4 monitoring microcomputer 5 logic circuit

Continued on front page F term (reference) 3G065 CA38 CA39 CA40 DA05 GA46 KA35 KA36 3G084 BA05 DA27 DA30 DA31 DA33 FA10 3G301 JB00 JB01 JB07 JB09 LA03 LC03 LC10 NB20 PF03Z

Claims (1)

[Claims] A throttle actuator for opening and closing a throttle valve of an internal combustion engine; a drive circuit for controlling the energization of the throttle actuator; a control microcomputer for generating a control signal for controlling an opening of the throttle valve; A monitoring microcomputer that detects an abnormality and outputs a detection signal; and a logic circuit that generates a logical product of the control signal and the detection signal and outputs a resultant signal to a drive circuit. An electronic throttle control device for controlling the energization of the throttle actuator in accordance with an output signal from the logic circuit.