JPS63275468A - Failure code memory indicating method for on-vehicle electronic control device - Google Patents

Abstract

PURPOSE:To give warning to the driver by reading the code for failure eventually existing out of a failure code memory immediately after start of the device, wherein the failure code memory stores how each part of the total electronic control system is in failure, and by twinkling an indicator when a certain period has passed after starting. CONSTITUTION:An anti-lock brake control circuit 10 has a one-chip microcomputer 14, which has self-diagnostic function to know whether the function of the applicable CPU itself is normal with respect to the CPU as the nucleus. Its memory part stores a warning lamp twinkling indication program, a failure sensing program, and a failure code read program. At the time of implementing the failure sensing program immediately after start of the device, it is read whether there is a failure code stored in a failure code memory (EEPROM) 15, and when failure code is in memory, the warning lamp 19 is twinkled for a certain period of time after passage of a specified time after starting.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides an in-vehicle electronic control system for ensuring that operators such as drivers and service personnel are aware of the details of a malfunction encoded and stored in a non-volatile memory. The present invention relates to a method for displaying a fault code memory of an apparatus.

[Conventional technology]

Modern cars have anti-brake systems that optimally control the tire slip rate of the brake system while driving, effectively utilizing tire friction force under any road surface conditions, and allowing the brake system to operate efficiently. Lock brake control devices, traction control devices that effectively utilize tire friction force to control acceleration during vehicle acceleration, automatic transmission control devices that automatically shift and transmit engine shaft power, etc. Various electronic control systems are installed.

These electronic control systems issue commands to controls related to the vehicle's driving performance and stability, such as the above-mentioned brake braking and treadmill control, so whether or not their operation is normal is directly related to the safety of human life. and is extremely important. Therefore, the operation of these electronic control systems must be carefully checked at the time of shipping or periodic inspection of the vehicle.

To perform such inspection work, an electronic control unit that controls the electronic control system is generally provided with a self-diagnosis function that diagnoses whether each part of the electronic control system is operating normally. In this self-diagnosis, the output signals of each part mentioned above are compared with a reference signal to determine whether it is normal or abnormal, and the judgment signal is coded together with other necessary information such as the location of the diagnostic part and sent to the electronic control unit. When it is desired to display the self-diagnosis results, the fault codes are stored in a fault code memory provided in the fault code memory, and when it is desired to display the results of the self-diagnosis, this is done by concealing the path from the electronic control unit to the display monitor and activating it using a switch or the like.

Once stored in the fault code memory, the diagnostic data stored as described in 2 is retained even after the electric current of the electronic control unit is cut off, and even after the fault location has been removed. It is kept as is.

One method for displaying the diagnostic content data stored in memory is to use the electromagnetic control system of the brake braking device controlled by the electronic control device when the vehicle is stopped when the electronic control device is used for anti-lock control. A method has been adopted in which a check connector for an actiniator such as a valve is disconnected, the details of the failure are read out from a fault code memory, and the presence or absence of the failure is indicated by a warning lamp.

Another display method is to equip the electronic control unit with an information output terminal (check terminal) other than the warning lamp, read the fault data from the fault code memory, and send a code to the monitor via this output terminal. There is a way to display it. The technology behind this method is that the warning lamp is generally configured not to light up unless a current failure has occurred even if a failure code is stored in the failure code memory.

As yet another method, a method combining the above two methods has also been adopted. In this case, the lamp lighting display is an LE installed in the electronic control unit instead of the warning lamp.
Some use D lamps, and these lamps are generally installed in a position that is not visible to the driver.

[Problems to be Solved by the Invention] However, the conventional display method described above has a non-volatile fault code memory, and even if a fault code is written in the non-volatile fault code memory, there is no current fault in the control system. Normally, nothing is displayed, and it is displayed only when a special operation for inspection is performed.

Further, even if there is an information output section such as an LED lamp that constantly displays the fault code in the fault code memory, this display lamp is hidden in a position where it cannot be seen by the general driver during normal driving operations.

For this reason, the current situation is that drivers are not shown any fault codes that have occurred in the past but have not yet been detected.For example, in the case of anti-lock brake control devices, anti-lock If a failure that occurs during normal driving in the summer when the brake control device hardly operates is left untreated, the control device may not operate at other times when anti-lock control is really needed. Some of the causes of failures are failures that cannot be detected unless certain conditions occur, such as failures that cannot be detected unless the vehicle is being driven.
Therefore, there are some failures that can only be detected when anti-lock control is really needed. Conventionally, monitoring devices have not been configured to repeatedly warn the driver about such failures, so warning lights are displayed at the time of failure. This is because once you ignore a warning, it will not be repaired.

It should be noted that non-volatile fault code memory is advantageous in storing and retaining faults that cannot be detected unless under a specific situation as mentioned above, and it is not recommended to install it in an electronic control system where such faults can occur. This will help improve service when an incident occurs.

The present invention has been made in view of the current state of the display method of fault code memory of in-vehicle electronic control units as described above, and it uses simple parts and components compared to conventional in-vehicle electronic control units.
By simply installing a control program, the warning lamp blinks to indicate whether or not there is a failure in each part of this electronic control system, and at least one warning light is displayed when the car is started.
The purpose is to warn the driver at all times and to inform the driver that there is a malfunction in any part of the electronic illumination system, thereby facilitating early detection and repair of malfunctions in the electronic control device.

Means for Solving Problem c] In this invention, as a means for solving the above problem,
Immediately after the in-vehicle electronic control unit is started, the presence or absence of a failure code is read out from the failure code memory, which uses a contingency memory that stores the failure details of each part of the entire electronic control system, including this electronic control unit, and the failure is detected. When the code is stored, a method is adopted in which the code is displayed by flashing at least once on a display connected to the electronic control unit after a predetermined period of time after startup has elapsed.

[Effect]

When the electronic control unit is started, a program built in the central processing unit is started at the same time, and the presence or absence of a fault code is read from the fault code memory. The fault code is written by a fault detection program that checks the presence or absence of a fault in each part of the electronic control unit during normal control program operation, and runs in parallel at regular intervals to detect the current fault. Performed when detected. When it detects that there is a fault code in the fault code memory, the system displays the presence of these faults separately from the lighting of a warning lamp that is used as an indicator at startup, for example to check for a warning lamp burnout. Therefore, the warning lamp will flash after a certain period of time. Therefore, the driver can know the presence or absence of a fault code not only for the current fault but also for the past fault, even if a fault has occurred in the past (past fault) but is not currently detected as a fault.

If there is a current malfunction, the warning lamp will remain lit to indicate the malfunction.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a fault code memory display method according to the present invention is applied to an anti-lock brake control device will be described in detail below with reference to the accompanying drawings.

10 is anti-lock brake control circuit (electronic control unit W)
, Sl to S are wheel speed sensors, 11 is an input processing circuit, 1
2 is a binarization circuit, 13 is a level converter, 14 is a one-chip microcomputer including a central processing unit, 15 is a fault code memory and is an electrically erasable ROM (EEPROM) for storing fault codes, 16 17 is a driving circuit for a warning lamp; 17 is a relay driving circuit; 18 is a solenoid driving circuit; 19 is a warning lamp; 20. ~n is a solenoid of a solenoid valve, and 21 is a power supply control relay.

The anti-lock brake control circuit is for electrically controlling the brake system of a car, and when depressing the brake pedal to decelerate the car, the rotational speed of the running wheel is detected by wheel speed sensors S, ~S4. The signal is detected by the one-chip microcomputer 1 via the input processing circuit 11.
This one-chip microcomputer 14 calculates the wheel speed, slip rate, vehicle speed, etc. according to a predetermined program, and compares it with the standard vehicle speed, etc., and calculates the slip rate on a snowy road. When the wheel speed falls below the reference vehicle speed due to tire slip on a high road surface and the slip rate exceeds a predetermined value, the command signal from the calculation result activates the solenoid 20 of the solenoid valve of the brake braking device. ~7, the brake pedal is repeatedly opened and closed in a short period of time regardless of whether the brake pedal is pressed to increase or decrease the brake pressure on the wheels so that the wheel speed approaches the slip ratio where the tire friction force is at its maximum. This is an electronically controlled n-circuit that prevents wheels from locking and provides sufficient efficiency in braking. In this case, the solenoid of the solenoid valve is for opening and closing the solenoid valve inserted into the hydraulic piping system of the hydraulic system that constitutes the brake braking device that is controlled by the anti-lock brake control device. By opening and closing, the operation of the wheel cylinders that drive the disc brakes of each wheel is controlled, and the brakes are turned on and off.

Although not shown, the one-chip microcomputer 14 of the control circuit 10 is equipped with a self-diagnosis function for diagnosing whether the central processing unit, which is the heart of the one-chip microcomputer 14, is functioning normally. If there is an abnormality in the function as a result of self-diagnosis, the warning lamp 19 is turned on and the details of the failure are stored in the failure code memory 15 in the form of a failure code.

In addition to this, the one-chip microcomputer 14 stores in its storage section a warning lamp flashing display program, a failure detection program, a failure code reading program, etc., which will be described later.

A digital signal representing engine rotation is input to the one-chip microcomputer 14 from the first terminal (hereinafter abbreviated as ALT-L terminal) of the alternator, which generates electricity when the engine starts, via the binarization circuit 12. be done.

Further, a test code terminal (abbreviated as Sin in the figure) is connected to a level converter 13 for the one-chip microcomputer 14.
An input signal for activating the fault indication program is inputted via. This test cord terminal is normally open and the output of the level converter 13 is Low. When the terminal is grounded with an appropriate switch, the output of the level converter 13 becomes the old gh (hereinafter abbreviated as "FH"), which indicates a failure. The program is started.

The power supply control relay 21 connects solenoids 20, to 7 of electromagnetic valves.
This is a relay for controlling the power supply of the electromagnetic valve, and is intended to ensure that the solenoids 201 to 7 of the solenoid valves do not operate by cutting off the power to this relay when a failure occurs.

Solenoid valve 20. ~7 is one-chip microcontroller 14
The solenoid drive circuit 18 is driven by transmitting the output signal as a result of the calculation in the solenoid drive circuit 18.

The operation of this embodiment configured as described above will be explained with reference to the flowchart of FIG. 2 and FIGS. 3 and 4.

First, when the IGN (ignition) switch is turned on, power is immediately supplied to the anti-lock brake control circuit 10, and the program shown in the left flowchart of FIG. 2 is immediately started. When this program starts, the memory of each part that commands the operation of this program is set to 0 as an initial setting, the output to the power control relay 21 is turned on, and the warning lamp output is turned on. The contents stored in 15 are read out,
The display waiting counter provided in the one-chip microcomputer 14 is reset to zero. At the knee, permission for timer interrupt is granted, and the process moves to the control program and failure detection program, which will be explained next.

As shown in the center of FIG. 2, this program mainly consists of a control program and a failure detection program. The control program is the anti-lock brake control circuit 1 described above.
This control program starts immediately when power is supplied to the anti-lock brake control circuit 10, and calculates wheel speeds and the like. At the same time, the failure detection program operates while the control program remains in operation.

The failure detection program detects, for example, wheel speed sensor operation, input processing circuit operation, etc. while the control program is operating.
・This is a program that detects whether there is a failure in each part of the control device. If no failure is detected by this failure detection program, the program returns to the original program, and if a failure is detected, the program moves to the failure detection program shown on the right side of FIG.

In the fault detection program, the warning lamp is immediately turned on, and the past data already stored in the fault code memory 15 is read out. This past data is compared with the contents of fault knee 1 detected by the fault detection program,
If the fault code is new, it is written to a predetermined address in the fault code memory 15. Then, it is determined whether the detected failure is serious enough to stop the operation of the anti-lock brake control circuit, and if it is determined to be a serious failure, the power control relay 21 is turned OFF. When there is no zero-fold failure that outputs a command signal, or immediately after the power control relay 21 is turned off, this program returns to the failure detection program, and then returns to the original program.

Upon returning to the original program, it is immediately determined whether the potential of the ALT-L terminal is lower than a predetermined value. If it is low, a warning lamp ON output is continuously given so that the warning lamp remains lit to check for core breakage. Note that the operation of the program after the above-mentioned return will be explained with reference to FIG.

Thereafter, it is determined once again whether the voltage at the ALT-L terminal is lower than a predetermined value, and when the rotation of the engine that has started late rises and this voltage becomes higher than the predetermined value, the output of the warning lamp is turned off. When the warning lamp turns off, the engine starter also turns off at the same time.
becomes. The time it takes for the above OFF output to be output is T in Figure 3.
This corresponds to the time w, which is the time required to initialize the system and the time the engine is in the OFF state. After the warning lamp is turned off, a predetermined time Tw is waited for to elapse, and a display wait counter is incremented in accordance with this waiting time.

Next, it is determined whether the count on the display waiting counter is greater than 1 second or not, and if No, the above operation is repeated and 1
If more than a second has passed and a fault code is stored in the fault code memory, a warning lamp will be displayed blinking and will be repeatedly turned on and off for 10 seconds at intervals of 0.5 seconds in this embodiment. . After 10 seconds, the warning lamp will turn off. If there is no fault code in the fault code memory, the blinking display will not be performed.

In the above operation, the control program and the failure detection program are automatically operated at a fixed time period by the hardware timer function inside the one-chip microcomputer 14, independently of the flashing warning lamp display program. Therefore, the details of the fault detected by this program are always written into the fault code memory each time a new fault occurs. As a result, when a past fault code stored in the fault code memory is read out immediately after the warning lamp flashing display program is started, the warning lamp flashes once immediately to warn the driver. Ru.

Instead of the flashing display of the warning lamp, it is also possible to change the number of times a fault code is displayed to indicate the importance of the fault. It is also possible to create a pattern that makes it easy to give a warning to the driver by displaying the same message for all failures.

Furthermore, instead of the blinking display by the warning lamp, or together with the blinking display, as shown in FIG.
The contents of the fault code memory can also be displayed blinking on the monitor.

[Effects] Since this invention employs the fault code memory display method as described above, the ALT
- A binarization circuit is attached to process the input signal of the L terminal, and if there is failure data including past failures stored in the failure code memory, the warning lamp blinks at least once at the start. It is possible to repeatedly warn when starting the engine that there is a malfunction in one of the electronically controlled cylinders. This method can be implemented by simply adding a small number of components to the electronic control unit and storing a simple program in a one-chip microcontroller, and can detect the presence of a failure condition without requiring various tests using external test equipment. This is useful for improving service and reliability of electronic control equipment.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of an anti-lock brake control device, FIG. 2 is a flowchart for displaying a fault code memory according to the present invention, and FIG. 3 is a diagram illustrating the timing of lighting and blinking of a warning lamp. FIG. 4 is a diagram illustrating the pattern of blinking time of the warning lamp. 10... Anti-lock brake control circuit, 12
... Binarization circuit, 13 ... Level converter, 14... One-chip microcomputer, 15 ...
-Fault code memory.

Claims (1)

[Scope of Claims] 1) Immediately after the in-vehicle electronic control unit is started, a failure code is detected from a failure code memory using a non-volatile memory that stores failure details of each part of the entire electronic control system including this electronic control unit. An on-vehicle electronic control device characterized in that the presence or absence of a code is read out, and when a fault code is stored, the code is flashed at least once on a display connected to the electronic control device after a predetermined time has elapsed after startup. How to display fault code memory. (2) A fault code memory display method for an on-vehicle electronic control device according to claim 1, characterized in that a warning lamp is used as the indicator. (3) The time when the predetermined time has elapsed is the time when the engine is started after the IGN switch is turned on, the warning lamp is turned off from being lit, and the light-off state is after the elapse of a predetermined time. A method for displaying fault code memory in automotive electronic control units.