JPS6189918A - Engine cooling device for vehicle - Google Patents

Abstract

PURPOSE:To prevent overheating of an engine due to failure of a fan control circuit, by controlling that the device does not turn the fan off until the temperature detection means detect engine temperature drop in an on-off control device controlling a cooling fan in response to the engine temperature. CONSTITUTION:A motor 27, which drives a fan of engine radiator, is connected to a relay 15 controlled by a thermal switch 1 which detects temperature of cooling water. Also, a relay 5, having a normally shut contact 9, is connected to the thermal switch 1, and the contact 9 is connected to the motor 27 through a diode 11. When the temperature of cooling water is high, the contact B of the thermal switch 1 shuts, the relay 15 shuts and the motor 27 is driven, and when the temperature is low, the contact A shuts and the motor is stopped. Since the relay 15 is self-maintained through the diode 11, the motor 27 is driven even if the switch 1 fails, and overheating of the engine is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a cooling device for a vehicle engine equipped with, for example, a radiator fan.

[Description of Prior Art] As a conventional cooling device for a vehicle engine, for example,
-There is one published in Publication No. 528. As shown in Fig. 2C in this type of vehicle engine cooling system, a thermal switch 101 closes the contact when it senses that the water temperature in the engine cooling system, such as a water jacket, has exceeded a predetermined value. Then, a current IC flows from the power supply 123 to the coil 117 of the thermal relay 115 via the thermal switch 101.
flows in. As a result, the coil 117 is energized and the normally open contact 125 of the thermal relay 115 is closed to form a circuit, so that a current iM is applied from the power supply 123 through the normally open contact 125 to the motor that blows cooling air to the radiator. Electric power is supplied to the fan 127, and the motor fan 127 is driven.

However, in the above configuration, after the thermal switch 101 detects that the water temperature of the engine cooling system has exceeded a predetermined value and closes, the motor fan 127, which blows cooling air to the radiator, is operated. For example”-
If a failure occurs such as the harness cover of the sensor coming off due to vibrations of the vehicle, the power supply from the power supply 123 to the motor fan 127 is cut off, so the motor fan 12
7 is stopped. Therefore, if the supply of cooling air to the engine is cut off and the vehicle continues to run in that state, the temperature of the engine will rise and the engine will eventually overheat.

[Object of the Invention] Therefore, the present invention aims to improve the above-mentioned problems.The purpose of the present invention is to prevent the sensor, such as a thermal relay, that detects the temperature of the gate from malfunctioning after it detects a temperature higher than a predetermined value and closes. To provide a cooling filter for a vehicle engine that does not cause the engine to overheat even when the engine is heated.

[Structure of the Invention] The features of the present invention for achieving the above object include means for detecting whether or not the temperature of the engine has exceeded a predetermined value; a cooling means for cooling the engine, which is driven when the temperature is detected and stopped when the engine is detected to be below a predetermined value; A cold Nl device for a vehicle engine includes a stop regulating means for regulating the driving of the cooling means from being stopped until a temperature value below is detected.

In the above configuration, when the d temperature detection means (thermal switch) detects that the temperature of water circulating in the engine cooling system has exceeded a predetermined value, the cooling means (a motor fan that blows cooling air to the radiator) A circuit is formed to drive the .

Since the circuit is formed as a self-holding relay circuit, the cooling means continues to be driven until the engine temperature detecting means detects that the water temperature value has fallen below a predetermined value. Therefore, even if the circuit is opened due to a malfunction such as poor contact in the temperature detection means, the cooling means continues to be driven while the vehicle is running.

[Description of Embodiment] FIG. 1 is a control circuit diagram of a cooling device for a vehicle engine according to an embodiment of the present invention.

In Fig. 1, a thermal switch 1 as an engine temperature detection means has a contact A that closes when the engine cooling water temperature is below a predetermined value, and a contact A that closes when the water temperature exceeds a predetermined value. Contact point B is provided. Wiring 3 is connected to the contact A.
The coil 7 of the relay 5 is connected through the relay 5. A wiring 13 having a normally closed contact 9 of a relay 5 and a diode 11, which are opened when the coil 7 is excited, and a wiring 19 having a coil 7 of a relay 15 are connected to the contact B in parallel. . The wiring Pii 13 and the wiring 19 are connected to the wiring 21, respectively. The wiring 21 is the power supply 2
3, a relay 15 is connected in parallel with the wiring 3 and opens when the coil 17 is excited;
The engine has a normally closed contact 25 and a motor fan 27 for blowing cooling air to the cooling water sent from the water jacket of the engine to the radiator via an outlet hose or the like.

This circuit has a self-holding function using relay 7 and relay 15, and forms a stop regulating means.

The operation of the above circuit will now be explained.

If the temperature of the cooling water circulating in the engine's cooling system is below a predetermined value, the contact A side of the thermal switch 1 is opened and the current iA supplied from the power supply 23 flows through the contact A of the thermal switch 1 to the coil. 7 and excites the coil 7. The normally closed contact 9 is therefore in an open state, which remains open until the coil 7 is demagnetized. When the temperature of the cooling water increases with the engine temperature and exceeds a predetermined temperature value, the thermal switch 1 detects this and closes the contact A.
is opened, and contact B is also opened.

Therefore, the current is supplied from the power source 123 excites the coil 17 via the contact B of the thermal switch 1, so the normally closed contact 25 is closed, and the current is applied to the motor fan 27 that blows cooling air from the power source 23 to the radiator. iv flows in and drives the motor fan 27. The normally closed contact 9 remains open until the thermal switch 1 closes the A contact again and excites the coil 7. Therefore, even if the contact B opens due to, for example, the harness coupler of the thermal switch 1 coming off due to vehicle vibration, a portion of the current iM will continue to flow to the coil 17 via the diode 11 and the normally closed contact 9. Therefore, the coil 17 is self-maintained without being demagnetized. Therefore, the motor fan 27 continues to drive until the fault in the thermal switch 1 is recovered and the normally open contact 9 is opened by closing the A1g point again, or until the vehicle stops running, and the motor fan 27 continues to drive. Cooling air is continuously blown into the cooling water flowing into the lot 1-1 through an outlet hose or the like.

The content described above only relates to one embodiment according to the present invention, and does not mean that the present invention is limited to the above content only. For example, an electronic circuit such as a micro combi coater may be used instead of a self-holding relay circuit. The drive of the motor fan may be controlled using a control means.

As explained in "Effect 1 and above", according to the present invention, even if a failure occurs after the engine temperature detecting means detects a temperature higher than a predetermined value and drives the cooling device, the engine It is possible to provide a cooling device for a vehicle engine that does not cause any problems.

[Brief explanation of drawings]

FIG. 1 is a control circuit diagram of a vehicle cooling device according to an embodiment of the present invention, and FIG. 2 is a control circuit diagram of a vehicle cooling device according to an example of the prior art. 1. Thermal switch 15. Relay 5, relay 17. Coil 7, coil 25. Normally open contact 9, normally closed contact
27. Motor fan 11, diode

Claims (1)

[Claims] An engine temperature detection means for detecting whether or not the temperature of the engine has exceeded a predetermined value; A cooling means for the engine whose driving is stopped when the engine temperature is detected, and a driving of the cooling means is stopped until the engine temperature detecting means detects a temperature value equal to or less than a predetermined value after the driving of the cooling means is started. 1. A cooling device for a vehicle engine, characterized in that it has a stop regulating means for regulating the cooling of a vehicle engine.