JPH07323755A - Cruise control device - Google Patents

Abstract

PURPOSE:To detect the uncontrollable condition without causing the energy loss by detecting the voltage drop of a switching element to judge the impossible braking of an actuator in a cruse control device containing a plurality of switching elements to drive the actuator for the cruise control. CONSTITUTION:In a motor driving means 7a in an actuator driving means, a motor 22a is driven to the direction to open a throttle valve when MOS-FETs 51, 53 are turned on, and the upstream voltage of the MOS-FET 53 is inputted to an A/D converter 13. The voltage corresponds to the voltage drop at the MOS-FET 53, and is a specific voltage in the normal condition, but when an open abnormality is happened in the circuit, the voltage drop at the MOS- FET 53 is not generated, and the specific voltage is not detected then. This constitution judges whether any open abnormality is present or not in the circuit by detecting the voltage to be inputted to the A/D converter 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cruise control device which enables constant speed traveling, and more particularly to detection of an uncontrollable state of the cruise control device.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 5, a cruise control motor 105 for controlling the opening of a throttle valve 103 separately from the operation of an accelerator pedal 101 and a motor 105 for reversibly driving the motor 105. The actuator drive means 107 having a built-in motor drive circuit including a plurality of switching elements, the setting conditions for cruise control and the actual traveling state are fetched, and the switching state of the switching elements of the motor drive circuit 107 is determined based on these. A cruise control device 100 including a microcomputer 109 for controlling is known. In order to detect the open abnormality of the motor 105 in the cruise control device 100, it is general to interpose the resistor 111 for open detection and detect the voltage drop thereof.

[0003]

However, in the cruise control device 100, the resistor 111 for open detection is used.
However, there is a problem in that the energy loss there occurs and the cruise control device 100 cannot be designed to the limit. In addition, the cost increases due to the increase in the number of parts.

Therefore, an object of the present invention is to detect an uncontrollable state in a cruise control device without causing energy loss.

[0005]

A cruise control device of the present invention made to achieve the above object is an actuator for cruise control for controlling an opening of a throttle mechanism as described in claim 1. And an actuator drive circuit including a plurality of switching elements for reversibly driving the actuator,
A cruise control device having a control circuit that takes in setting conditions for cruise control and an actual traveling state and controls the switching state of the switching element of the actuator drive circuit based on these, further comprising at least the switching element. The voltage drop detection means for detecting the voltage drop in one element, and the actuator based on the voltage drop detection value when the switching element which is the detection target of the voltage drop detection means is controlled to the ON state. And a determination means for determining whether or not control is disabled.

This cruise control device pays attention to the fact that a switching element causes a voltage drop to act as a resistance element although it is slight, and further, whether or not the switching element is turned on is determined by a control signal from a control circuit. It was completed by focusing on the fact that it can be easily discriminated by.

According to this cruise control device,
Even if the switching element whose voltage drop is detected is controlled to be in the ON state, if the voltage drop above the predetermined level does not occur in the switching element,
It can be determined that the actuator is out of control. This is because when the actuator is in the controllable state, a current flows through the drive circuit, causing a certain voltage drop in the switching element in the ON state, but when the actuator is in the uncontrollable state, Because a current does not flow through the device, no voltage drop is detected even if the switching element is on.

Here, as described in claim 2, it is preferable that the switching element to be detected by the voltage drop detecting means is an element that functions as a ground side of the actuator. At this time, as described in claim 3, it is preferable that the voltage drop detection means is configured by inputting an upstream voltage of the switching element to an analog / digital converter (ADC).

This is because the ground voltage level is always zero, and it is possible to accurately determine whether or not a predetermined voltage drop has occurred by detecting the upstream voltage of the switching element on the ground side. . Since the ADC is often attached to the control circuit, it can be dealt with by simply increasing or changing the channel without adding a new configuration as the voltage detecting means, and the cruise control device as a whole has no additional components. This is advantageous in that the actuator abnormality can be determined without the need.

On the other hand, since the power supply voltage may fluctuate, simply detecting only the voltage value is not enough to detect the voltage drop in the switching element between the actuator and the power supply. However, it is necessary to take the difference between the upper and lower voltage values of the element, which requires a slightly complicated configuration.

[0011] Claims 1 to 3 configured as above
In the cruise control device according to any one of
Further, when the determination means determines that the actuator control is disabled, a provision is also provided for suspending the cruise control, or when the determination means determines that the actuator control is disabled, the state It is preferable to provide an informing means for informing the driver that the vehicle is in the state of ???, and a storage means for storing the state of the vehicle as reference data. By providing these configurations, it is possible to prevent the cruise control from being fixed in a specific state, further inform the driver of the need for repair, and make the work in the repair shop smooth later. Because it will be possible.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an overall configuration diagram of the cruise control device of this embodiment. This device is installed in an automobile equipped with a gasoline engine together with an electronically controlled fuel injection device (EFI).

A cruise ECU 1 for carrying out constant speed traveling control
A battery 5 is connected to the vehicle via an ignition switch 3. By turning on the ignition switch 3, power is supplied to the cruise ECU 1 and the microcomputer 8 can be operated. Power is supplied to the actuator drive means 7 built in the cruise ECU 1 via the main relay 9. The main relay 9 is connected to a main switch 11 for constant speed traveling control, and when the main switch 11 is turned on, the main relay 9 is turned on, power is supplied to the actuator driving means 7, and the actuator driving means 7 is supplied. Can be operated.

The microcomputer 8 includes ROM, RA
It is configured as an ordinary microcomputer provided with M, I / O, bus lines and the like. Various sensors are provided to the microcomputer 8 via an input buffer 12.
Signals from switches are input. Further, some of these signals are input to the microcomputer 8 via the analog / digital converter (ADC) 13. In the present embodiment, the control switch 14 for constant speed traveling control, the stop lamp switch 16 that is turned on when the driver depresses the brake pedal, the idle switch 18 that is turned on when the throttle opening is fully closed, and is proportional to the vehicle speed. A signal from a vehicle speed sensor 20 that generates a frequency signal is input. The control switch 14 includes a set switch 14a, a resume switch 14b, and a cancel switch 14c.

The microcomputer 8 sequentially executes the program commands stored in the ROM based on the signals of these various sensors and switches, and outputs the driving commands to the actuator driving means 7 as necessary. ing. The actuator driving means 7 includes an actuator 22.
Is a drive circuit for driving the motor 22a and executes a drive output corresponding to the drive command to the motor 22a and the clutch 22b provided inside the actuator 22 in response to the drive command from the microcomputer 8. For example, the motor 22a is controlled by the output of the actuator driving means 7 in the forward / reverse rotation and the rotation speed thereof. When the clutch 22b is energized by the output of the actuator driving means 7, the rotation of the motor 22a is transmitted to the throttle mechanism (throttle valve) 26 of the engine 24. This allows the microcomputer 8 to adjust the driving force of the engine 24, and as a result, to control the speed of the vehicle.

As a well-known structure, the accelerator pedal 28 and the throttle valve 26 are connected so that the depression amount of the accelerator pedal 28 is linked to the throttle opening. The depression operation of the accelerator pedal 28 and the rotation operation of the motor 22a connected to the throttle valve 26 by the clutch 22b can be operated independently of each other. This is reflected in the rotation of the throttle valve 26. Therefore, even if the motor 22a rotates so that the throttle valve 26 is fully closed, if the accelerator pedal 28 is depressed, the throttle opening degree corresponds to the depression amount of the accelerator pedal 28. On the contrary, even if the accelerator pedal 28 is not depressed, if the motor 22a rotates in the direction to open the throttle valve 26, the motor 2
The throttle opening corresponds to the rotation of 2a. Since such a configuration is well known, detailed description will be omitted.

An electronically controlled fuel injection device (EFI) 30 is provided in addition to the above-described constant speed traveling control device. The EFI 30 calculates a required amount of fuel according to the load on the engine 24, and supplies the fuel from the injector 32 into the intake air. Further, the EFI 30 also executes fuel cut control under a predetermined fuel cut condition, in which the idle switch 18 is turned on while traveling.

In this embodiment, the signals from the motor drive means 7a of the actuator drive means 7 are input to the two channels of the ADC 13. The details of this portion are configured as shown in FIG. As shown in FIG. 2, the motor driving means 7a is configured as a 12-pin integrated circuit, and includes an H-bridge 50 that uses four MOS FETs 51 to 54 as switching elements, and an M-bridge 50.
A control logic 55 that controls switching of the OS FETs 51 to 54 is built in.

Pins 1, 2, and 10 are connected to the microcomputer 8 and are used for exchanging signals between the control logic 55 and the microcomputer 8.
Pins 3 and 9 are connected to the main relay 9 and are used to apply a battery voltage to the motor driving means 7a.

Pin 4 is connected to the terminal MO which is the positive side when the motor 22a is driven in the opening direction, and pin 8 is the terminal MC which is the negative side when it is driven in the closing direction. Connected to. Pin 4 is also connected between MOS FETs 51 and 54, and Pin 8 is connected between MOS FETs 52 and 53.

The 7th pin is connected to the MOS FETs 53 and 54 and is grounded. ADCs are also connected to pins 4 and 8 via protective resistors 61 and 62.
13 is connected. And further Zener diode 6
It is also dropped to the ground via 3,64.

Pin 5, Pin 6, Pin 11 and 12
The pin number does not play a particularly important role in this embodiment. The motor 22a includes limit switches 65 and 66 for the throttle opening direction and the throttle closing direction, respectively.
Is provided to regulate the operating range of the motor 22a. The motor 22a opens the throttle valve when current flows in the illustrated MO direction and closes the throttle valve when current flows in the MC direction.

With the above configuration, the motor driving means 7
In a, when the MOS FETs 51 and 53 are turned on, a circuit as shown in the schematic diagram of FIG. 3 is configured, and the motor 22a is driven in the throttle valve opening direction. At this time, A
The upstream voltage of the MOS FET 53 is input to the DC 13. This voltage corresponds to the voltage drop in the MOS FET 53, and is a predetermined voltage (for example, about 0.5 V) under normal conditions. On the other hand, when the open abnormality occurs in the circuit, the voltage drop in the MOS FET 53 does not occur, so that the above-mentioned predetermined voltage is not detected. In addition,
When the motor 22a is driven in the throttle valve closing direction, the MOS FETs 52 and 54 are turned on and the ADC1
The upstream voltage of the MOS FET 54 is input to 3.

Thus, according to this embodiment, the MOS F
Paying attention to the property that the ETs 51 to 54 function as a slight resistance, the upstream voltage of the MOS FETs 53 and 54 on the ground side can be detected as a predetermined voltage without being affected by the power supply voltage under normal conditions. Whether or not there is can be easily determined.

Next, the control processing relating to the determination of the open abnormality in the microcomputer 8 and the response to the abnormality will be described. In this control processing, as shown in FIG. 4, it is determined whether or not the motor drive signal is being output (S1), and if it is being output, the upstream voltage V1 of the ground side MOS FET input from the ADC 13 is determined. It is determined whether the voltage is lower than the predetermined voltage V0 (S2). When V1 <V0, it can be determined that the motor driving means 7a has an open abnormality, and therefore the following abnormality processing is performed.

In the abnormality processing, first, the clutch is controlled to be off (S3), and the throttle valve is made free. As a result, the throttle valve is released from the drive state by the motor, and the drive state corresponds only to the accelerator operation by the driver. Next, turn off the main relay (S
4) After that, the constant speed traveling control cannot be performed. Then, the notification lamp 71 (see FIG. 1) installed at a predetermined position in the driver's seat is informed that the constant-speed traveling is impossible (S5). Subsequently, the detected abnormality state is stored in the predetermined abnormality storage means 72 (S6). This stored content is read out by short-circuiting the test terminal (T terminal) 73 in a repair shop or the like, and is used as reference information during repair.

As described above, according to the present embodiment, the open abnormality of the drive motor circuit can be detected without interposing the conventional open detecting resistor or the like, and the cruise system is a system with less energy loss. A control device can be provided. Then, by stopping the constant speed traveling control at the time of an abnormality, the driver is notified of the necessity of repair by not causing an uncontrollable state, and the reference information at the time of repair is stored to notify the driver of the repair. Achieved ease.

The embodiment of the present invention has been described above.
The present invention is not limited to this, and it goes without saying that various modes can be adopted without departing from the scope of the invention. For example, the switching element forming the drive circuit is not limited to the MOS FET, and any element that can be a resistor may be used. Also, in the embodiment,
It is also possible to detect the voltage drop in the MOS FETs 51, 52 on the power supply side, instead of the MOS FETs 52, 54 on the ground side.

[0029]

According to the cruise control device of the present invention, an uncontrollable state in the cruise control device can be detected without newly interposing a resistor or the like, and energy loss is not increased. As a result, it is possible to limit the design of the cruise control device and contribute to cost reduction of the cruise control device.

Further, according to the apparatus of claims 2 and 3, even if the power supply voltage fluctuates, it is possible to always make an accurate judgment without being affected by the fluctuation. Particularly, according to the device of the third aspect, it is possible to provide a simple and inexpensive device which can be dealt with only by increasing or changing the channel of the ADC.

Further, according to the fourth aspect of the present invention, when the cruise control device falls into an uncontrollable state,
It is possible to return to the state without cruise control without fixing the control as it is. In addition, claim 5
According to the device described, since the driver is informed that the actuator cannot be controlled, the driver can easily know the necessity of repair, and even the repair shop reads the reference data during repair, It is possible to easily determine what kind of repair is required. Therefore, when the actuator cannot be controlled, the repair can be performed smoothly and promptly.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a cruise control device according to an embodiment.

FIG. 2 is a configuration diagram of a motor drive circuit according to an embodiment.

FIG. 3 is a schematic diagram of a motor drive circuit when driving in a throttle opening direction in the embodiment.

FIG. 4 is a flowchart of abnormality determination and abnormal time control processing according to the embodiment.

FIG. 5 is a configuration diagram of a conventional cruise control device.

[Explanation of symbols]

3 ... Ignition switch, 5 ... Battery,
7 ... Actuator driving means, 7a ... Motor driving means, 8 ... Microcomputer, 9 ... Main relay, 11 ... Main switch, 13 ... Analog / digital converter (ADC), 14 ... Control switch, 16 ... Stop lamp switch, 1
8 ... Idle switch, 20 ... Vehicle speed sensor, 2
2a ... motor, 22b ... clutch, 24 ...
Engine, 26 ... Throttle mechanism (throttle valve), 28 ... Accelerator pedal, 30 ... Electronically controlled fuel injection device (EFI), 51-54 ... MOS F
ET, 55 ... Control logic, 71 ... Notification lamp, 72 ... Abnormality storage means, 73 ... Test terminal (T terminal).

Claims (5)

[Claims] 1. An actuator for cruise control for controlling the opening of a throttle mechanism, an actuator drive circuit including a plurality of switching elements for reversibly driving the actuator, and setting conditions for cruise control. In a cruise control device having a control circuit for capturing the actual traveling state and controlling the switching state of the switching element of the actuator drive circuit based on these, further, a voltage drop in at least one element of the switching element Whether the actuator is uncontrollable based on the voltage drop detection means for detecting and the voltage drop detection value when the switching element detected by the voltage drop detection means is controlled to be in the ON state. And a determination means for determining Cruise control device, characterized in that. 2. The cruise control device according to claim 1, wherein the switching element to be detected by the voltage drop detection means is an element that functions as a ground side of the actuator. 3. The cruise control device according to claim 2, wherein the voltage drop detection means is configured by inputting an upstream voltage of the switching element to an analog / digital converter. . 4. The cruise control device according to any one of claims 1 to 3, further comprising a stopping means for stopping the cruise control when it is judged by the judging means that the actuator cannot be controlled. A cruise control device characterized by being provided. 5. The cruise control device according to any one of claims 1 to 4, further, when the determination unit determines that the actuator cannot be controlled, the driver is informed of the state. A cruise control device comprising: an informing unit for informing, and a storage unit for storing that state as reference data.