JPH07229444A - Cpu backup device - Google Patents

Abstract

PURPOSE:To surely prevent a vehicle from being stolen even in the case of destruction of CPU by starting an engine by means of a regular key switch, and stopping operation of CPU backup until perfect explosion is confirmed. CONSTITUTION:This CPU backup device is provided with a backup permission circuit 8 permitting operation of a CPU trouble detecting device 3 when an ignition signal 1a and a perfect explosion signal 1c are input from a CPU 1, and a discrimination device 9 discriminating whether a regular key switch is inserted or not. When the operation of the CPU 1 is abnormal immediately since the power source is ON, output of a backup permission signal 8a is prohibited even if the reset signal 2a from a CPU monitoring device 2 becomes L many times. Thereafter, when the CPU 1 returns to be normal, the reset signal 2a maintains the H condition, and the engine perfect explosion signal 1c becomes H. the backup permission signal 8a of the back-up permission device 8 is made H, and shift to a back-up mode is permitted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control device, and more particularly to a CPU backup device in a vehicle equipped with an anti-theft device.

[0002]

2. Description of the Related Art Conventionally, a method of optimally controlling an engine has been adopted by mounting an engine control device using a microcomputer. Furthermore, if this microcomputer fails, the vehicle cannot run, so C
A method has also been adopted in which a PU backup device is provided to enable traveling even if the microcomputer fails. This CPU backup device is disclosed in Japanese Patent Application No. 59-142366.

[0003]

In the above prior art, CP is used.
When the failure of U is detected, it is unconditionally switched to the CPU backup. However, to prevent theft of the vehicle,
In the engine control device equipped with the function of starting the control of fuel injection or ignition only when receiving the signal that the engine has been started by the key switch adapted to the vehicle, in the above configuration, the CPU is stolen by the thief. In some cases, the vehicle is intentionally destroyed and the vehicle is stolen.
In the above-mentioned conventional technology, no particular consideration is given to the prevention of vehicle theft.

It is an object of the present invention to provide a CPU backup device which is capable of preventing vehicle theft.

[0005]

The above problems can be solved by stopping the operation of the CPU backup until the engine is started with a regular key switch and it is confirmed that the complete explosion has been achieved. That is, when the CPU is operating normally and the CPU outputs a signal indicating that the engine has completely exploded, the CPU backup device may start operating.

[0006]

With the above construction, in addition to having a CPU backup function, the vehicle can be protected from theft even if the CPU is destroyed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of the present invention. 1 inputs various signals (not shown) of the engine,
CP that calculates various control parameters for optimally controlling the engine based on the signal and outputs as a control signal
U. Reference numeral 2 is a CPU monitoring device that gives a reset signal 2a to the CPU 1 when the CPU 1 is not operating normally. Reference numeral 3 is a CPU failure detection device which determines that the CPU 1 has failed when the reset signal 2a has been generated a predetermined number of times and outputs a backup switching signal 3a. Reference numeral 4 is a backup ignition device that outputs a backup ignition signal 4a so that the vehicle can travel when the CPU 1 fails. A switching circuit 5 supplies the ignition signal 1a from the CPU 1 to the ignition device 7 when the CPU 1 is normal and the backup ignition signal from the backup ignition device to the ignition device 7 when the CPU 1 is in failure, in response to the backup switching signal 3a. A rotation detector 6 detects the rotation of the engine and outputs a rotation signal 6a. A backup permission circuit 8 permits the operation of the CPU failure detection device 3 when the ignition signal 1a and the complete explosion signal 1c from the CPU 1 are input. Reference numeral 9 is a device for discriminating whether or not a regular key switch is inserted. When the regular key switch is discriminated, a key switch discriminating signal 9a is transmitted to the CPU 1.
When the key switch discrimination signal 9a is input, the CPU 1
Performs engine control processing in accordance with the rotation signal 6a and outputs a control signal such as the ignition signal 1a. However, when the key switch determination signal 9a is not input, it is determined that the key switch is not a regular key switch, and the ignition signal 1a or the like is not output even if the rotation signal 6a is input.

A conventional CPU backup switching method, that is, the operations of the CPU monitoring device 2 and the CPU failure detecting device 3 will be described with reference to a timing chart of FIG. C when CPU1 is normal
A pulse signal is output to the PU monitoring device 2 such that the program run signal 1b indicating that the program in the CPU 1 is operating normally is inverted every predetermined time (for example, every 10 mS). At this time, since the CPU 1 is operating normally, the reset signal 2a is fixed at HIGH and C
PU1 continues operation. However, when the operation of the CPU 1 becomes abnormal, the program run signal 1b does not output a pulse signal. At this time, after a predetermined time from the CPU monitoring device 2, the reset signal 2a having a predetermined time width (for example, 100 mS) is set to LOW to reset the CPU 1. When the CPU 1 does not output the program run signal 1b even when the reset signal 2a returns to HIGH, the reset signal 2a becomes LOW again. This state is repeated unless the program run signal 1b is output from the CPU 1. The CPU failure detection device 3 inputs this reset signal 2a, and when the number of times the reset signal 2a becomes LOW reaches a predetermined number (for example, 3 times), it is determined that the CPU 1 is in failure and the backup switching signal 3a is sent. HI
Set to GH and switch to CPU backup mode.
The above is the method of switching to the conventional CPU backup control. At this time, if the CPU 1 has failed since the power of the engine control device was turned on, the CPU 1
It will switch to backup mode and the engine will start with backup. However, although a key switch identification device is provided for the purpose of preventing theft, the CPU
If it becomes a backup, the engine will start regardless of the presence or absence of this device, and if the CPU1 is intentionally destroyed by a thief, the vehicle may be stolen.

FIG. 3 is a timing chart showing the operation of the present invention for preventing this. Immediately after the engine controller is powered on, the program run signal 1b is not output due to an abnormal operation of the CPU 1 and the backup permission signal 8a is not output even if the reset signal 2a becomes LOW several times. , It does not switch to backup mode. After that, if the CPU 1 returns to normal, the program run signal 1b is output normally, and the reset signal 2a maintains the HIGH state. Although not shown, when the key switch determination signal 9a is input from the key switch determination device 9 and normal engine control is started according to the rotation signal 6a, the ignition signal 1a is output in synchronization with the rotation signal 6a. It When the CPU 1 detects the complete explosion of the engine, the complete explosion signal 1c is set to HIGH. The backup permission device 8 receives these two signals and sets the backup permission signal 8a to HIGH to permit the shift to the backup mode. Since the complete explosion signal 1c is a signal output from the CPU 1, the complete explosion signal 1c may return to LOW when the CPU 1 performs an abnormal operation. Once the backup permission device detects a signal group from the CPU 1, it stores it and sets the backup permission signal 8a to H level.
It is fixed to IGH. After the backup permission signal 8a becomes HIGH, the CPU 1 becomes abnormal and the reset signal 2a repeats inversion again, and when the inversion is detected a predetermined number of times, the backup switching signal 3a becomes HIGH and the backup mode is entered. As a result, the CPU1
Even if you try to start the engine after destroying the vehicle, it will not go into backup mode and the vehicle will not be stolen. Further, after the engine is started once, if the CPU 1 becomes abnormal, the backup mode can be switched to, and the minimum required vehicle traveling can be secured. FIG. 4 is a configuration diagram showing an example in which the operation of the present invention is realized by another method. The same operation can be obtained by using the program run signal 1b as a signal indicating that the state of the CPU 1 is normal with respect to the configuration of FIG.

[0011]

As described above, the vehicle can be driven by the CPU backup in the engine control device having the antitheft function.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of the present invention.

FIG. 2 is a timing diagram illustrating operations of a CPU monitoring device and a CPU abnormality detection device.

FIG. 3 is a timing diagram showing the operation of the present invention.

FIG. 4 is a configuration diagram for realizing the object of the present invention with another configuration.

[Explanation of symbols]

1 ... CPU, 2 ... CPU monitoring device, 3 ... CPU failure detection device, 4 ... Backup ignition device, 5 ... Switching circuit, 6 ...
Rotation detector, 7 ... Ignition device, 8 ... Backup permission circuit, 1a ... Ignition signal, 1b ... Program run signal, 1c
... complete explosion signal, 2a ... reset signal, 3a ... backup switching signal, 4a ... backup ignition signal, 6a ... rotation signal, 9a ... key switch discrimination signal.

Claims (4)

[Claims] 1. A rotation detector for detecting the rotation of an engine,
An arithmetic device for calculating an engine control parameter based on an external engine start signal and a signal from the rotation detector and outputting an engine control signal, an abnormality detecting device for detecting an abnormal operation of the arithmetic device, and the arithmetic device. In an engine control device equipped with a backup device including an auxiliary device that enables traveling even when an abnormality occurs, the operation of the backup device is performed until a signal group including a predetermined pulse signal is output from the arithmetic device. A CPU backup device comprising a circuit that does not start. 2. The CPU backup device according to claim 1, wherein the engine control parameter is ignition timing, the engine control signal is an ignition signal, and the predetermined pulse signal is an ignition signal. . 3. The CPU backup device according to claim 1, wherein the predetermined pulse signal indicates that the arithmetic unit is operating normally, and when the predetermined pulse signal is not normally output, the arithmetic unit is operated. Which is a signal for generating a signal for returning the
Backup device. 4. The CPU backup device according to claim 1, wherein the fact that the signal group from the arithmetic unit is normally output is stored and held until the power source of the engine control device is turned off. .