JPH04301734A - Vehicle diagnosis system - Google Patents

Abstract

PURPOSE:To integrate the various kinds of functions for failure diagnosis as well as to flexibly deal with the various kinds of diagnoses. CONSTITUTION:The external connecting connector 41 of an interface box 40 is connected between the external connecting connector 7 of an ECU 10 and a connector 8 at the side of a vehicle via an adapter harness 42, and the interface box 40 and the ECU 10 are connected to a communication line 44. Furthermore, both a connector 45 for the communication line of the interface box 40 and a connector 69 for the communication line of a personal computer 50 are connected to a communication line 70, command signals are then sent to the interface box 40 from the personal computer 50 in accordance with the failure diagnosis program supplied from a floppy disc, and the data of the ECU 10 picked up by the interface box 40 is sent to the personal computer 50 thereafter, so that failure diagnosis is thereby carried out.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle diagnostic system for diagnosing failures by connecting a general-purpose computer to an electronic control unit mounted on a vehicle.

0002

[Prior Art] In recent years, electronic control systems in vehicles such as automobiles have become more sophisticated, and when this electronic control system breaks down,
In order to investigate the cause of the failure, large-scale and expensive specialized equipment was required.

[0003] Therefore, recently, for example, Japanese Patent Laid-Open No. 1-2
As disclosed in Japanese Patent No. 54835, a small and portable vehicle diagnostic device (
A select monitor) has been developed, and by connecting this select monitor to the vehicle's electronic control unit (ECU), data within the ECU based on the output signals of each sensor and each actuator, and the ECU for each actuator are displayed. It is now possible to diagnose internal control data.

0004

[Problems to be Solved by the Invention] However, since the above-mentioned select monitor only displays the data of the input/output signals of the ECU, the operator must refer to the manual for fault diagnosis and determine the fault based on the displayed data. The location must be determined.

[0005]Furthermore, since the fault diagnosis program of the select monitor is supplied by a ROM cassette, it cannot be easily changed, and depending on the nature of the fault, it may be necessary to add other measuring instruments such as a tester or oscilloscope for confirmation. This may result in an increase in work man-hours.

The present invention has been made in view of the above circumstances, and provides a vehicle diagnostic system that can easily integrate various functions for failure diagnosis and can flexibly respond to various types of diagnosis. It is intended to.

[0007]

[Means for Solving the Problems] The vehicle diagnostic system of the present invention includes a general-purpose computer capable of freely exchanging vehicle failure diagnosis programs, and a general-purpose computer connected between the general-purpose computer and an electronic control device mounted on the vehicle. , and an interface device that processes input/output signals of the electronic device according to instructions from the general-purpose computer.

[0008]

[Operation] In the vehicle diagnostic system of the present invention, an electronic control device installed in a vehicle and a general-purpose computer capable of freely exchanging fault diagnosis programs are connected via an interface device, and the electronic device can be controlled by commands from the general-purpose computer. The input and output signals are processed by the interface device,
Fault diagnosis is performed.

[0009]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings show an embodiment of the present invention; FIG. 1 is a circuit diagram of a system, FIG. 2 is a flowchart showing a control procedure on the personal computer side, and FIG. 3 is a flowchart showing a control procedure on the interface box side.

[Configuration] In FIG. 1, reference numeral 10 is an electronic control unit (ECU) mounted on a vehicle such as an automobile. , a personal computer 50 as a general-purpose computer is connected, and fault diagnosis is performed.

[0011] The ECU 10 is a central processing unit (CPU).
) 1, a read-only memory (ROM) 2, a read/write memory (RAM) 3, and an input/output (I/O) interface 4 are connected to each other via a bus line 5. O interface 4
A drive circuit 6 is connected to the output port of the drive circuit 6.
and the above-mentioned I/O interface 4 are connected to an external connection connector 7.

[0012] Also, the interface box 40
includes a microcomputer 20, a ROM 30 and a RAM 31 for system function expansion connected to the outside of the microcomputer 20, a communication processing circuit 32, an analog signal processing circuit 33, and a digital signal processing circuit 34.
, normally closed type relays RY1, RY2, RY3,
A drive circuit 35 for driving the relays RY1, RY2, and RY3 is built-in.

The microcomputer 20 has a CPU
21, ROM 22, RAM 23, timer 24, serial communication interface (SCI) 25,
An analog/digital (A/D) converter 26 is connected via a bus line 27, and this bus line 27 is extended to the outside to provide an R
It is connected to OM30, RAM31, and digital signal processing circuit 34.

Further, the SCI 25 is connected to the communication processing circuit 32, the A/D converter 26 is connected to the analog signal processing circuit 33, and the digital signal processing circuit 34 is connected to the drive circuit 35. and is connected to the relay coil of each relay RY1, RY2, RY3.

The relays RY1 and RY2 are interposed with respect to the input/output line extending from the digital signal processing circuit 34 to the external connection connector 41 so that the input line and the output line communicate with each other when the relay contacts are closed. Furthermore, the relay RY3 is interposed with respect to the input/output line extending from the analog signal processing circuit 33 to the external connection connector 41 so that the input line and the output line communicate with each other when the relay contact is in a closed state. has been done.

[0016] Also, the interface box 40
An external connector 41 is connected via an adapter harness 42 between the external connector 7 of the ECU 10 and a connector 8 on the vehicle side, and the connector 8 on the vehicle side has digital sensors 11 and analog sensors 12. and actuators 13 are connected.

The digital sensors 11 are sensors that output digital signals, such as an engine speed sensor, a vehicle speed sensor, an idle switch that turns on when the throttle is fully closed, and a full switch that turns on when the throttle is fully opened. The analog sensors 12 are, for example, sensors that output analog signals, such as an intake air amount sensor and a cooling water temperature sensor. The actuators 13 are actuators for various controls, such as an injector, an idle speed control valve, and a duty solenoid valve for controlling line pressure of an automatic transmission (AT).

[0018] Then, the above interface box 4
When the relay contacts of the relays RY1, RY2, and RY3 inside 0 are open, the signals from the digital sensors 11 pass through the digital signal processing circuit 34, and the signals from the analog sensors 12 pass through the analog signal processing circuit. 33 to the I/O interface 4 of the ECU 10, and signals from the drive circuit 6 of the ECU 10 are output to the actuators 13 via the digital signal processing circuit 34. That is, by turning on each of the above-mentioned relays RY1, RY2, and RY3 (energizing the relay coil and opening the relay contacts), the ECU 10 can disconnect input/output signals, limit the level of input/output signals, and set pseudo signals. It is now possible to perform processing such as output.

Furthermore, the interface box 4
A communication line connector 43 connected to the communication processing circuit 32 of 0 and a communication line connector 9 connected to the vehicle side connector 8 are connected, and the communication line connector 43 connected to the communication processing circuit 32 of
A communication line 44 from 2 is connected to the I/O interface 4 via the vehicle-side connector 8 and the connector 7 of the ECU 10 to read calculation data inside the ECU 10 or trouble data based on the self-diagnosis function. is now possible.

On the other hand, the personal computer 50 is, for example, a laptop-type personal computer, and includes a CPU 51, a ROM 52 storing a basic system program, a RAM 53, a direct memory access controller (DMAC) 54, and a hard disk drive (HDD) 55. A hard disk drive controller (HDC) 56 controls a floppy disk drive (FDD) 57, a floppy disk drive controller (FDC) 58 controls a floppy disk drive (FDD) 57, and a print controller (PRINT CONT) controls a printer (not shown).
) 59, a serial input output controller (SIO) 61 that controls the communication interface 60,
Keyboard for key input (KEY BOARD)
62, a display controller (DISP.CONT.) 65 that controls a display (DISP.) 64 such as a liquid crystal display or a plasma display, and a speaker controller (SP.CONT.) that drives a speaker 66. C
ONT. ) 67 are connected to each other via a bus line 68.

The interface box 40 and the personal computer 50 are connected to the communication processing circuit 3.
2, and a communication line connector 69 connected to the communication interface 60, the data of the ECU 10 is transmitted to the personal computer 50. In addition, the personal computer 5
Commands from 0 are sent to the interface box 40.

[System Operation] The operation of the system with the above configuration will be explained according to the flowcharts of FIGS. 2 and 3.

FIG. 2 shows a control program executed by the personal computer 50, which is stored in, for example, a floppy disk and supplied exchangeably.
7 and executed.

When this program is executed, first, in step S101, for example, whether to diagnose equipment such as digital sensors 11, analog sensors 12, actuators 13, etc., or whether to diagnose calculation data in the ECU 10, etc. is determined. A menu for selecting a fault diagnosis method is displayed, and in step S102, a loop waits for selection input of a fault diagnosis target method from the keyboard 62.

[0025] Here, when a selection input is made from the keyboard 62, the process proceeds from step S102 to step S103, and a command instructing content such as continuous acquisition or single-shot acquisition of data, for example, is sent to the interface box 40 in accordance with the selection input. . Next, the process proceeds to step S104, and waits for a response from the interface box 40. When there is a response from the interface box 40 due to command reception, the process proceeds to step S105, and for example, the digital sensors 11, analog sensors 1, etc.
2. Send a command instructing which signal data from the actuators 13 or data within the ECU 10 is to be collected.

Thereafter, in step S106, a response from the interface box 40 is waited for, and when the interface box 40 responds and transmits the acquired data, the received data is stored in the RAM 53 in step S107.
In step S108, the received data is displayed on the display 64, and the process returns to step S102. The data is displayed on the display 64 in accordance with the selected menu, for example, in a table format, graph format, signal waveform format, etc., and you can immediately check whether the data is normal or not without referring to a manual for fault diagnosis. displayed for confirmation.

Furthermore, if there is an abnormality in the signal data from the ECU 10, the personal computer 50 sends the abnormal signal to the interface box 40, cutting off the abnormal signal, restricting the signal,
By sending commands such as signal disconnection and pseudo signal output, fault diagnosis can be performed while avoiding adverse effects on the fault diagnosis target system.Furthermore, the pseudo signals can be used to control the ECU 10 side, digital sensors 11, analog It is possible to easily know which side, the sensors 12 or the actuators 13, is malfunctioning.

For example, if the ECU 10 is an engine control ECU, when the full switch output is taken into the interface box 40 and transmitted to the personal computer 50, the full switch output will be 0V when the throttle is not fully open. When the throttle is turned ON when the throttle is fully open, the voltage is 1.5V. Therefore, if the full switch output remains ON for more than a specified period of time, the full switch is abnormal, and as a result, the air-fuel ratio deteriorates and the problem occurs. It is determined that there is a possibility of this occurring, and a command to disconnect the full switch signal is sent to the interface box 40.

In other words, this full switch ON state will not continue for more than a predetermined time, and if the full switch fails and the ON state continues for more than a predetermined time, the ECU 10 will turn on the fuel even though the throttle is not fully open. The full switch signal is cut off because a full-open increase correction is performed on the injection amount, resulting in an excessive fuel injection amount and a deterioration of the air-fuel ratio.

Further, for example, when the output data of the cooling water temperature sensor is taken into the interface box 40 and transmitted to the personal computer 50, the output data of the cooling water temperature sensor is one of the parameters when setting the fuel injection amount. For example, since it changes linearly with the cooling water temperature and varies between 0 and 5V, the personal computer 50 determines that the cooling water temperature sensor is abnormal when the cooling water temperature output exceeds 5V. The output of this cooling water temperature sensor is limited, for example, so that it does not exceed 3V to prevent problems caused by too much or too little fuel injection amount.

Further, for example, the ECU 10 is an AT control ECU, and a duty signal for a line pressure control duty solenoid valve is taken into the interface box 40 and transmitted to the personal computer 50, and the duty ratio of this duty signal is 50. %, in the personal computer 50, for example, a pseudo signal with a duty ratio of 90% is sent to the interface box 40.
output to the line pressure control duty solenoid valve.

In other words, the duty signal for this line pressure control duty solenoid valve has a duty ratio of 50% when the throttle is fully closed, and a duty ratio of 90% when the throttle is fully open, and when the duty ratio is less than 50%, the AT range shift is Since the time slip becomes large and causes a serious problem in the AT, the duty signal from the ECU 10 is cut off, and instead, a pseudo signal with a duty ratio of 90%, for example, is sent from the interface box 40 to the line pressure control duty solenoid valve. This problem can be avoided by outputting to

On the other hand, when the control program on the interface box 40 side shown in FIG. 3 receives a command from the personal computer 50 in the reception waiting loop of step S201, the program proceeds to step S202 and interprets the received command.

[0034]Then, the process advances to step S203, and input/output signals of the ECU 10 are taken in based on the interpreted command.
For example, in the case of an analog signal, it is converted into digital data to obtain the necessary data. After that, in step S204,
The captured signal data of the ECU 10 is transmitted to the personal computer 50 and the program exits.

[0035] Furthermore, from the personal computer 50,
When a command such as signal disconnection, signal level restriction, signal disconnection, or pseudo signal output is sent, one of the normally closed relays RY1, RY2, and RY3 in the interface box 40 is inserted between the corresponding signal lines. Turn on the relay
do.

For example, in the case of the full switch abnormality described above, the normally closed relay RY2 is turned on, the output side of the digital signal processing circuit 34 is lowered to low level, and the full switch output signal to the ECU 10 is cut off. In addition, if the above-mentioned cooling water temperature sensor is abnormal and the signal level is to be limited, the normally closed relay RY3 is turned on and the analog signal processing circuit 33 is turned on.
When the signal from the cooling water temperature sensor input to the ECU 10 becomes 3V or higher, the input signal to the ECU 10 is fixed at 3V to limit the signal level, and when it is lower than 3V, the signal level is directly output to the ECU.
10.

Furthermore, if the duty signal for the line pressure control duty solenoid valve described above is judged to be abnormal and the signal is cut off to output a pseudo signal, the normally closed relay RY1 is turned on and the duty signal from the ECU 10 is output. In addition to cutting off the signal, the digital signal processing circuit 34
A pseudo signal with a duty ratio of 90% is output from the line pressure control duty solenoid valve.

[0038] This eliminates the need for a manual for failure diagnosis, allows integration of various functions for failure diagnosis such as an oscilloscope, digital tester, and signal check board, and enables automatic measurement for diagnosis. Furthermore, a personal computer 5 which is a general-purpose computer
0, so by supplying the fault diagnosis program on a floppy disk, it is easier to change the program, compared to when supplying it on a semiconductor memory such as ROM.
It can be easily replaced and running costs can be significantly reduced.

[0039]

Effects of the Invention As explained above, according to the present invention, it is possible to easily integrate various functions for failure diagnosis, and it is also possible to flexibly respond to various diagnoses, thereby providing comprehensive failure diagnosis. Excellent effects can be obtained, such as being able to perform

[Brief explanation of drawings]

[Figure 1] System circuit diagram

[Figure 2] Flowchart showing the control procedure on the personal computer side

[Figure 3] Flowchart showing the control procedure on the interface box side

[Explanation of symbols]

10 Electronic control device 40 Interface box (interface device)

Claims (1)

[Claims] Claim 1: A general-purpose computer capable of freely replacing a fault diagnosis program for a vehicle is connected between the general-purpose computer and an electronic control device mounted on the vehicle, and input/output signals of this electronic device are transmitted to the general-purpose computer. A vehicle diagnostic system characterized by comprising: an interface device that processes according to commands from the vehicle.