JPH0554458B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a switching circuit that selectively supplies power to two systems, particularly a main electronic control device and an emergency control device of an electronically controlled vehicle. This invention relates to a switching circuit for power supply to.

(Prior Art) Recently, an increasing number of vehicles are controlled by electronic control devices consisting of microcomputers. This type of vehicle is configured such that a main electronic control unit controls the rotational speed of the internal combustion engine, gear switching of the transmission, and the like. However, it has been proposed to provide a vehicle with an emergency control device so that the vehicle can at least continue to run even if the main electronic control device fails.

Such an emergency control device switches an emergency state changeover switch to the emergency state side when the driver notices an emergency situation in the vehicle, such as when automatic gear shifting is impossible due to a failure of the main control device. With this operation, the power to the main control device is cut off, and instead of this, power is applied to the emergency control device, which controls the vehicle instead of the main control device.

(Problems with the Prior Art) However, in such a vehicle, for example, if the main electronic control device and the emergency control device are accidentally switched while the vehicle is running, the emergency control device will cause the transmission to move backward and only to the first gear. It is extremely dangerous if the system is configured to have only limited functionality.

(Object of the Invention) The object of the present invention is to provide a system under which it is permissible to switch the power supply between the main control device and the emergency control device of the vehicle in order to avoid the dangers caused by the above-mentioned erroneous operation. The object of the present invention is to provide a switching circuit that can be switched only when.

(Summary of the Invention) An object of the present invention described above is to provide a switching circuit that selectively supplies power to two systems, a main control device that controls a vehicle, and an emergency control device for backing up the main control device. a double-throw switch that switches the power supply to the main control device; and when the main control device is operating normally, power is continuously supplied to the main control device regardless of the switching state of the double-throw switch; This is achieved by a switching circuit characterized in that it includes a relay switching means that supplies power only to the emergency control device by switching the double-throw switch.

(Example) FIG. 1 is a circuit diagram showing a switching circuit of the present invention, and FIG. 2 is a logic circuit diagram thereof.

In FIG. 1, 1 is a power supply, 2 is a power switch, and 3 is a system A which is, for example, a main control device.
(indicated by 9) and a double-throw switch for switching the power supply to system A (indicated by 10) which is an emergency control device, and 4 is a condition sensor for temperature, rotation speed, pressure, etc. The condition sensor 4 contains signals indicating whether the main control device is operating normally, such as a temperature signal from an engine temperature sensor, a rotation speed signal from an engine rotation sensor, and a pressure signal from a hydraulic pressure sensor for transmission control. Various signals for making judgments are collectively input and output to the comparator described below. 5 is a comparator that compares the signal from the condition sensor 4 with a preset value and outputs an output when the set value is reached. Each time the main control device issues an operation command to each device of the vehicle, the main control device outputs a signal corresponding to the command to the comparator 5.
In the comparator 5, the signal sent from the main controller is set as a preset value in the comparator 5, and the set value is updated every time a new signal is sent.

On the other hand, an operation command is issued from the main control device, and the device that receives the command operates according to this command, and a signal corresponding to the state of the operation is sent to the condition sensor 4. A signal is sent to comparator 5.

The comparator 5 compares a preset value with the signal from the condition sensor 4, and outputs, for example, "1" if they match, and outputs "0" if they do not match. 6 is a relay activated by the output of the comparator 5. This relay 6 operates when, for example, "1" is output from the comparator 5, and does not operate when, for example, "0" is output. 8 is a relay that operates when power is supplied to system A9 and relay 6 is operated; 7 is a relay that operates when power is supplied to system B10 and relay 6 is operated;
Reference numerals 11 and 12 indicate backflow prevention diodes, respectively. In addition, 6a is a normally open contact of relay 6, 7a,
7b is the normally closed contact and normally open contact of the relay 7, 8a,
8b indicates a normally closed contact and a normally open contact of the relay 8, respectively.

Further, in FIG. 2, 21 and 22 indicate OR gates, and 23 and 24 indicate AND gates, respectively.

Next, the operation of the switching circuit of the present invention will be explained with reference to FIG.

In FIG. 1, when the power switch 2 is closed, power is supplied from the power source 1 to the system A9 through the contact A of the double-throw switch 3 and the normally closed contact 7a of the relay 7. At this time, when the signal from the condition sensor 4 reaches the set value of the comparator 5, the relay 6 of the comparator 5 is activated and its normally open contact 6a is closed. Therefore, the power supply is connected to the normally closed contact 7 of the relay 7.
a, is fed through diode 11 to relay 8, which activates, closing its normally open contact 8b and, conversely, opening its normally closed contact. As a result, relay 8
enters a self-holding state, and at the same time, the power supply to system B10 is cut off. In this state, only system A9 is in operation. That is, this state indicates that the main control device is operating normally.

In this state, even if the double-throw switch 3 is switched from contact A to contact B, since the normally closed contact 8a of the relay 8 is open, power is not supplied to the system B10. On the other hand, normally open contact 8b of relay 8
is closed, power is supplied to the system A9 through the normally open contact 8b of the relay 8 and the normally closed contact 7a of the relay 7. In this way, even if the double-throw switch 3 is operated by mistake, switching of the power supplies of system A and system B will be suppressed.

In this state, that is, the state in which the double-throw switch 3 is connected to contact B, if the signal from the condition sensor 4 cannot clear the set value of the comparator 5, that is, if the main control device malfunctions, the signal from the condition sensor 4 becomes inoperable. There is no output, so relay 6 stops operating, its normally open contact 6a opens, relay 8 is released from self-holding, and system B
Power is supplied to system A 10, and power supply to system A9 is cut off.

When the relay 6 is operated with the contact A of the double-throw switch 3 on and the relay 6 on, when the relay 6 turns off, that is, when a failure occurs in the main control device, the self-holding of the relay 8 is released. Since the state returns to that shown in FIG. 1, when the driver switches the double-throw switch 3 to the contact B side, power supply to system A is cut off and power is supplied to system B instead.

Since the circuits are configured symmetrically for system A and system B, switching the power supply to system A in the above-mentioned state, that is, the state where power is being supplied to system B, is exactly the same. , when the relay 6 is operating according to the output of the condition sensor 4, it is suppressed, and when the relay 6 is not operating, switching is enabled.

FIG. 2 shows the above-mentioned circuit configuration as a logic circuit diagram. When the condition input has a logic value of 1, switching of power supply between system A and system B is suppressed, and when the condition input has a logic value of 0, switching of power supply between system A and system B is suppressed. It is possible to switch at times.

(Effects of the Invention) As explained above, the switching circuit of the present invention is configured to enable switching of the power supply to the two systems only when switching is possible. This allows you to avoid danger when operating the switch.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a switching circuit of the present invention. FIG. 2 is a logic circuit diagram of the circuit of FIG. 1...Power source, 2...Power switch, 3...Double throw switch, 4...Condition sensor, 5...Comparator, 6, 7, 8...Relay, 9...System A,
10... System B, 11, 12... Diode, 21, 22... OR gate, 23, 24...
AND gate.

Claims (1)

[Scope of Claims] 1. In a switching circuit that selectively supplies power to two systems, a switching circuit that switches power supply to a main control device that controls a vehicle and an emergency control device for backing up the main control device. a throw switch, which continuously supplies power to the main controller regardless of the switching state of the double-throw switch when the main controller is operating normally, and which supplies power to the double-throw switch in the event of a failure of the main controller; A switching circuit comprising a relay switching means that supplies power only to an emergency control device by switching.