JPS58210340A - Trouble data holding device in electronic control system for vehicle - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a battery exhaustion as well as to make a diagnosis troubleshooting ever so easy, by setting up a circuit feeding or intercepting the power to or from a memory according to the on-off state of an ignition switch and the presence of emergence of any trouble data there. CONSTITUTION:An operation circuit 2 is provided with an operation program and a trouble diagnostic program. Even when an ignition switch 4 is turned to OFF, power is still fed to a memory 3 from a battery 5 via a thyristor 7 and thereby memory data in the memory 3 continue to be held. Doing like this, in case trouble happens in a system, infallible repairs take place without delay by reading out the trouble diagnostic data stored in the memory 3.

Description

[Detailed Description of the Invention] The present invention is applicable to electronic control systems such as engines.
Failure of a vehicle electronic control system that detects abnormalities in the input/output data or control calculations of the electronic control calculation unit, writes failure diagnosis data to the memory, and retains the data stored in the memory even after the ignition switch is turned off. The present invention relates to a data holding device.

Conventionally, as an electronic control system for an engine using a microcomputer, for example, as shown in FIG.
Consists of an interface 1, an arithmetic circuit 2, and a memory 3 for temporarily storing data.
．． A calculation circuit 2 inputs detection signals from sensors, engine cooling water temperature sensors, etc., and performs calculations based on a predetermined control program.
The control signal is fully output through interface 1, and the actuator is driven to control fuel injection (eight EGI control points, timing control (IGN control), and exhaust gas recirculation control iG).
R control), idle rotation control (engineering SC control), etc.

By the way, in such an electronic control system, various electronic controls are processed in real time on a time-sharing basis, and the overall system configuration including the sensor and actuator assembly is quite complex. When a failure or a calculation error occurs, it takes considerable effort to find the failure location and investigate the cause of the failure.

Therefore, the arithmetic circuit 2 is equipped with a check function to determine whether the input/output signals and arithmetic control are normal or not, and when it is determined that an abnormality has occurred, the failure location, degree of failure, number of occurrences, etc. are stored in the memory 3 for failure diagnosis. Write it as data (
・Ru.

In order to accommodate such writing of failure diagnosis data to the memory 3 and to prevent the data stored in the memory 3 from being erased even if the ignition switch 4 is turned off, the data is written from the battery 5 to the memory 3 without going through the ignition switch 4. Even if the ignition switch 4 is turned off, the power supply to the memory 3 is completely interrupted so that all stored data can be retained.

However, the frequency of failure occurrence in the electronic control system described above is extremely low due to the use of highly reliable sensors, control calculation elements, etc.;
Failure diagnosis data Fi is not written to. However, in conventional devices, power is always supplied to the memory 3 from the battery 5 regardless of the presence or absence of fault diagnosis data. Although memory retention can be performed reliably, if the vehicle is parked during the invasion period with no fault diagnosis data written (or not), the current consumption of memory 3 will be approximately 10%.
When the voltage was about mA, there was a risk of causing a so-called battery rise.

The present invention has been made in view of the above, and is designed to prevent battery failure in the engine control system, etc. stored in the memory, or in a device that maintains memory by supplying full power to the memory even after the ignition switch is turned off. In order to save power, in addition to a circuit that supplies and cuts off power to the memory depending on whether the ignition switch is turned on or off, it also detects failure data and continues to supply power to the memory even after the ignition switch is turned off. A means is provided to continue supplying power to the memory, and to cut off power supply to the memory when no failure data appears.

The present invention will be explained below based on the drawings.

FIG. 2 is a block diagram showing one embodiment of the present invention.

First, to explain the entire configuration, 1 is an interface, which includes an intake air amount sensor, a vehicle speed sensor, a crank angle sensor, and 0. Input lines for sensors, engine coolant temperature sensor, etc. are connected, and fuel injection control is also performed.

Output lines are taken out to actuators that perform ignition timing control, exhaust gas recirculation control, idle rotation control, etc. The 2#i arithmetic circuit has all the predetermined arithmetic programs that perform all of the engine's fuel injection control, ignition timing control, exhaust gas circulation control, idle rotation control, etc., and also outputs sensor input signals and actuators through one interface. It is equipped with a fault diagnosis program that checks whether there are any signal abnormalities and whether various control calculations are being performed correctly.

Reference numeral 3 denotes a memory in which failure diagnosis data indicating the failure location, degree of failure, number of failures, etc. is written when abnormalities in input/output data and calculation errors are determined by the failure diagnosis program of the arithmetic circuit 2.

A battery 5 is connected to the interface 1 and the arithmetic circuit 2 via an ignition switch 4,
On the other hand, a battery 5 is connected to the memory 3 via a memory holding circuit 6 provided in parallel with the ignition switch 4. The memory holding circuit 6 connects the positive side of the battery 5 to the memory 3. A diode D connects the battery 5 to the memory 3 via the thyristor 7 and the ignition switch 4. is connected to the output line of the memory retention signal eh, which is output when the memory retention signal eh is determined.Furthermore, the memory retention circuit 6 is provided with a relay 8, which is connected to the memory retention signal eh outputted through the interface 1. In order to turn off the thyristor 7 that is turned on, the relay contact (normally closed contact) 8ak of the relay 8 is connected in series with the thyristor 7.

Next, the action will be explained.

When the ignition switch 4 is turned on by operating the ignition key, power from the battery 5 is supplied to the interface 1 and the arithmetic circuit 2, and is also supplied to the memory 3 via the diode Df of the memory holding circuit 6.
The control system enters an operating state and various engine controls are performed based on the control program in the arithmetic circuit 2.

During control by this system, if a failure occurs in one of the sensors inputting a signal via the interface 1, for example, an abnormality occurs in which the input signal instantaneously becomes 0 volts, then the arithmetic circuit 2 The failure diagnosis program determines whether this sensor is abnormal and writes failure diagnosis data to a predetermined address in the memory 3. At the same time, arithmetic circuit 2
outputs the memory retention signal eh to the gate of the thyristor of the memory retention circuit 6 via the interface 1, the thyristor 7 is turned on, and the power is supplied to the memory 3 via the diode D1 and the thyristor 7, respectively. Supply will begin.

Of course, when the arithmetic circuit 2 determines that a failure has occurred, an indicator light is turned on through the entire interface 1 to notify the operator of the occurrence of the failure.

When the ignition switch 4 is turned off with the fault diagnosis data written in the memory 3 and the thyristor 7 of the memory holding circuit 6 turned on, the power supply to the interface 1 and the arithmetic circuit 2 is cut off. Although the system operation stops, the thyristor 7, which was once turned on by the memory retention signal eh, remains in the on state even if the memory retention signal eh is cut off, so even if the ignition switch 4 is turned off, the thyristor 7 remains on. A battery 5 and a stain source are supplied to the memory 3 via the battery 7, and the data stored in the memory 3 continues to be held even when the ignition switch 4 is turned off.

Therefore, if a system failure occurs, the memory 3
By reading the fault diagnosis data stored in the VCX through an external connection such as a checker, the location of the fault, the extent of the fault, and the number of times the fault has occurred can be immediately known, and accurate repairs can be carried out quickly.

In addition, to cut off the power supply to the memory 3 after the repair and adjustment of the faulty part is completed, the relay 8 is energized through the interface 1 by a predetermined restoration operation, and the relay contact 8ai
By opening, the thyristor 7 is turned off.

Furthermore, the thyristor 7 can be turned off by applying a reverse bias to the gate of the thyristor via the interface 1 instead of the relay 8.

On the other hand, if the ignition switch 4 is turned off without any failure diagnosis data being written to the memo IJ3, the thyristor 7 of the memory holding circuit 6 will also be turned off, so that when the ignition switch 4 is turned off, The power supply to the memory 3Vc is cut off.In other words, when the fault diagnosis data is stored in This will definitely prevent the vehicle from being put away.In addition, when the failure diagnosis data is written to the memory 3, the vehicle will be immediately taken to a repair facility for inspection, so the memory 3
If you leave the vehicle parked with the power supply continuing to the battery, there will be no problem with the upstream Fi if the fault diagnosis data is written to memory 3.

FIG. 3 is a circuit block diagram showing another embodiment of the present invention, and this embodiment uses a latch-up relay for the thyristor 7 of the memory holding circuit 6 in the embodiment of FIG. All other features and other configurations are the same as the embodiment shown in FIG.

That is, when the power supply to the memory 3 is in the normal state where no failure diagnosis data is written, the diode D is turned on when the ignition switch 4 is turned on.
When the fault diagnosis data is written into the memory 3 through the interface 1, the latch-up relay 10 is energized by the memory retention signal ehVc output from the arithmetic circuit 2 through the interface 1, and its relay contacts are 10ai close, latch-up Once the relay 10 is activated, the relay contact 10ai has the function of mechanically closing even if the relay is de-energized. Even if switch 4 is completely turned off, relay contact 10aFi remains closed,
After the ignition switch 4 is turned off, power is supplied to the memory 3 via the relay contact 10ak, and all stored data is retained.

To restore the latch-up relay 10, the latch-up relay 10 must be energized again by a predetermined restoration operation.
The relay contact 10a, which had been closed until then, opens (and returns to the normal power supply state).

As explained above, according to the present invention, the configuration is written into the memory by determining all the abnormalities in the input/output data of the electronic control calculation unit or the control calculation, and even after 7Ic after the ignition switch is turned off, the stored data in the memory is In this device, even if a person turns on the ignition switch when data is written to the memory, the power supply to the above-mentioned equipment continues, so that the data is written to the memory and -・When memory retention is required, the power source continues to be supplied (even after the ignition switch is turned off), and the data is retained in the memory, and if the data is not written (・even after the ignition switch is turned off), Since it is not necessary, the power to the memory is cut off when the ignition switch is turned off, and power is supplied to the memory regardless of the presence or absence of stored data.The occurrence of overvoltage can be almost completely eliminated. You can get the following effect.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional example, FIG. 2 is a circuit block diagram showing an embodiment of the present invention, and FIG. 3 is a circuit block diagram showing another embodiment of the present invention. 1...Interface 2...Arithmetic circuit 3.
・・Memory 4・Ignition switch 5・Battery 6・Memory holding circuit 7・Thyristor 8・°°Relay 1
0... Latch-up relay patent applicant Nissan Automotive Manufacturing Co., Ltd.

Claims (1)

[Claims] A circuit that supplies and cuts off power to a memory according to whether the ignition switch is turned on or off, and control system failure data stored in the memory? , a circuit that supplies power to the memory and retains the memory even after the ignition switch is turned off; and detecting means for detecting writing of failure data to the memory; When writing is detected (・When the ignition switch is turned off, the power supply to the memory is continued, and when failure data writing is detected (・When the ignition switch is turned off, the power supply to the memory is continued.) Failure data retention device for vehicle electronic control systems.