JP2528654B2 - Electronic control unit for automobile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is used as an electronic control device for controlling an engine mounted on an automobile and other traveling systems.

The present invention relates to an electronic control unit for a motor vehicle, which includes a program-controlled microprocessor. In particular, it relates to the operation mode of the control circuit and its mode switching.

[Conventional technology]

The electronic control unit for automobiles has sensors that detect the operating state of the operating ends such as pedals, levers and switches located in the driver's seat, engine rotation state, vehicle speed, setting state of clutch and transmission, and other states. An electric signal output from these sensors is provided as an input signal, a calculation is executed according to a predetermined program, and a control signal is sent to the engine and other running systems according to this calculation.

The main part of this electronic control unit is a control circuit including a microprocessor and a program executed by this microprocessor, and the control circuit needs to operate with high reliability. In order to properly maintain this control circuit, the control circuit has a self-diagnosis function.

That is, in addition to the operation mode in which the input signal from each sensor is fetched and the calculation for generating the control signal is executed as described above, a failure to execute the separately-implemented self-diagnosis program as the second operation mode is performed. A diagnostic mode is provided, and it is configured such that a self-diagnosis can be performed by switching to the failure diagnostic mode by a predetermined operation. The predetermined operation is, for example, an operation of connecting a display circuit for displaying the self-diagnosis result to the control circuit with a connector. That is, a switch (herein referred to as a diagnosis switch) that is automatically closed when the connector is connected is provided inside the connector, and when the switch is closed, the operation mode is changed to the failure diagnosis mode. Will be converted.

[Problems to be solved by the invention]

When such a control circuit is installed in an electronic control unit of a vehicle and a test is conducted, when a failure is displayed in the failure diagnosis mode, the cause of the failure is not in the control circuit and the electrical signal from the sensor is not appropriate. There is something due to that. In this case, it is necessary to test whether the sensor is operating normally, and if not, adjust or replace the sensor. The adjustment of the sensor is, for example, adjustment of the connection position between the accelerator pedal and the stroke sensor.

In the past, in order to test and adjust this sensor, a special measuring device was required, and an operator who was skilled in handling and measuring this measuring device had to be used.

The present invention solves this problem, and an object of the present invention is to provide a device that does not require a special measuring device and can perform this work easily even by a skilled worker.

[Means for solving problems]

A first feature of the present invention is that the control circuit is provided with an adjustment mode as a third mode in addition to the above two modes. This adjustment mode tests whether or not the electrical signal from each sensor is producing the correct signal for its operation, and assists in adjusting each sensor or the operating end to which it is attached, and so on. It is a mode to perform. A second feature of the present invention is to provide a mode changeover switch for changing over to this adjustment mode.

[Action]

When in the failure diagnosis mode, the mode change switch is operated to change to the adjustment mode. The adjustment mode tests and displays whether the electrical signal from the sensor is in the normal range. Further, in the adjustment mode, the input signal of the sensor that needs to be adjusted is directly or standardized with a standard value and displayed to assist the adjustment.
For example, when adjusting the connection position between the accelerator pedal and the stroke sensor, by operating the control circuit in this adjustment mode, the standard connection position is displayed and the adjustment operator recognizes this. You can know the correct connection position. No special measuring device is required for this adjusting operation.

Therefore, this adjustment mode may be provided individually for each sensor requiring adjustment.

In order to select a desired one from a plurality of adjustment modes provided individually, it is preferable to distinguish it from the number of times the mode switch is operated.

The mode change switch is a switch that is effective in the failure diagnosis mode in principle, and is not used in the operation mode. Therefore, the switch used in the operation mode can also be used as the mode conversion switch. Particularly, it is preferable that the inching switch for instructing the low speed running in the operation mode is also used as the mode changing switch.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, a microprocessor 1 is provided with a stroke sensor 4 for detecting a depression amount of an accelerator pedal 3 as a sensor, a speed sensor 7 for detecting a vehicle speed from a rotation of a propeller shaft 6, and a transmission 5 via an input / output control device 2. Position sensor 2 to detect the set position of
4, rotation speed sensor 13 that detects the rotation speed of the engine 12
Is connected, and the control signal is connected to the injection pump 14 that controls the fuel supply amount. Further, the sensor lever outputs of the transmission lever 18 and the inching switch 17 are connected to the input / output control device 2, and the control signals are the solenoid valve 10 for controlling the clutch and the transmission 5.
Is connected to two control solenoid valves 22 and 23 for controlling the.
The microprocessor 1 and the input / output control device 2 form a control circuit.

Further, the input / output control device 2 includes a microprocessor 1
Switch to set the fault detection mode to the
25, a display circuit 26, and an inching switch 17 for instructing a slow speed running are connected. The diagnosis switch 25 is a switch for switching from the operation mode, which is the first mode, to the failure diagnosis mode, which is the second mode, and is automatically closed by connecting the display circuit 26 for failure display. Switch is used.

In such a device, when the power supply is started, the control circuit automatically starts operating in the operation mode. For example, the most standard program executed in the operation mode is the injection pump 14 depending on the depression amount of the accelerator pedal 3 detected by the stroke sensor 4 and the rotation speed of the engine 12 detected by the rotation speed sensor 7. Is a control for controlling the opening degree of the fuel cell and adjusting the fuel supply amount.

The inching switch 17 in this operation mode will be described. When the inching switch 17 is operated, the control circuit controls the clutch 8 in the half-clutch state to perform a slow speed running. The slow speed traveling by the inching switch 17 is used when the position of the automobile is slightly moved, such as when the automobile is parked.

The display circuit 26 is provided in the service factory in principle, and is not used by general car drivers. By connecting the display circuit 26 to the electronic control unit, the diagnosis switch 25 is automatically closed. By detecting this, the control circuit switches the operation mode from the operation mode to the second mode, that is, the failure diagnosis mode. At this time, the microprocessor 1 performs various self-diagnosis according to the installed program, and causes the display circuit 26 to display the test result and the detected failure type.

In this embodiment, the program executed in the failure diagnosis mode uses commercially available software for self-diagnosis of the microprocessor 1, and determines whether or not each checkpoint is normal, When it is normal, the display circuit 26 displays normal, and when an abnormality is determined, information relating to the abnormality is displayed by a simple symbol.
Display on 26. The correspondence between this symbol and the content of abnormality can be recognized by the symmetry table provided with the above program.

Some of the abnormal displays indicate that the value of the input signal from each sensor is not within the predetermined range.
In principle, this is not an abnormality in the control circuit itself, but an abnormality in the input signal.

In the apparatus of this embodiment, such an abnormality in the input signal can be easily tested and adjusted by changing the operation mode of the control circuit to the adjustment mode which is the third mode.

That is, by operating the inching switch 17, the control circuit switches from the failure detection mode to the adjustment mode which is the third mode. As illustrated in FIG. 2, when the inching switch 17 is operated once, the adjustment mode A is set. Similarly, when the operation is performed twice, the adjustment mode B is set. When the operation is performed three times, the adjustment mode C is set. Generally, when the operation is performed M times, the adjustment mode M is set. Adjustment mode A is a mode in which the input from the stroke sensor 4 of the accelerator pedal 3 is tested for a standard value and the result is displayed on the display circuit 26. When the accelerator pedal 3 is released and the input value is not within the allowable range of the standard value, the connection position between the accelerator pedal 3 and the stroke sensor 4 can be adjusted. Adjustment mode B is a mode in which the input value from the rotation speed sensor 13 is displayed on the display circuit 26. Adjustment mode C displays the input value of the position sensor 24 of the transmission 5
It is the mode displayed on 26. In this way, for multiple types of adjustment mode, by displaying the input from each sensor directly or with a value normalized to the standard value,
The state of each sensor can be known and each sensor can be appropriately adjusted.

When the work in each adjustment mode is completed, the control circuit is reset to return to the operation mode which is the first mode. Reset is performed by once stopping the power supply to the control circuit. In practice, the control circuit can be reset by turning off the key switch of the automobile once and then returning the key switch to the on state.

〔The invention's effect〕

The present invention, as described above, by providing the adjustment mode as the third operation mode of the control circuit, while testing the state of each sensor, the adjustment of each sensor without using a special measuring device, Further, there is an effect that it can be performed without requiring special skill.

Further, when there are a plurality of adjustment modes, the device configuration can be simplified by distinguishing them by the number of times the mode changeover switch is operated.

Furthermore, when existing switches are used as the mode changing switch, it is not necessary to provide another mode changing switch, and the device configuration can be simplified.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is an explanatory diagram for explaining a mode switching state of the present invention. 1 ... Microprocessor, 2 ... Input / output control device, 3
...... Accelerator pedal, 4 ...... Stroke sensor, 5 ......
Transmission, 6 ... Propeller shaft, 7 ...
Rotation speed sensor, 8 ... Clutch, 9 ... Clutch actuator, 10 ... Solenoid valve for clutch control, 11 ...
Transmission control mechanism, 12 …… Engine, 13 ……
Rotation speed sensor, 14 ... Injection pump, 17 ...
… Inching switch, 18 …… Transmission lever, 22,23 …… Transmission control solenoid valve, 24…
… Transmission position sensor, 25 …… Diagnostic switch, 26 …… Display circuit.

Claims (3)

(57) [Claims] 1. A control circuit including a microprocessor which takes in output signals of a plurality of sensors as input signals and gives a control signal to an engine, and a program control means of the control circuit operates as its operation mode based on the input signals. In the electronic control unit for an automobile, which is provided with an operation mode for executing the above-mentioned control signal to generate the control signal and a failure diagnosis mode for executing the self-diagnosis of the control circuit, the program control means of the control circuit has In addition, it is provided with an adjustment mode for testing the state of the sensor and assisting the adjustment work, and further provided with a mode conversion switch for instructing a mode change from the failure diagnosis mode to the adjustment mode, and the control circuit is When the mode conversion switch is operated, the failure diagnosis mode is switched to the adjustment mode. Automotive electronic control unit, characterized in that it comprises means for. 2. The electronic control unit for an automobile according to claim 1, wherein the mode changeover switch also serves as an inching switch for instructing a low speed running in the operation mode. 3. The adjustment mode includes an individual adjustment mode corresponding to two or more sensors, and the means for performing the conversion to the adjustment mode has each individual adjustment mode according to the number of times the mode changeover switch is operated. The electronic control unit for an automobile according to claim (1) or (2), which includes a means for performing the conversion to.