JPS63189611A - Automobile engine cooling motor fan control device - Google Patents

Abstract

PURPOSE:To prevent the titled device from overheating under engine stop condition by providing a water temperature sensor that cuts off electric supply when cooling water temperature is lower than the prescribed after a key switch is cut off, to a control unit which controls an engine cooling motor fan driving relay. CONSTITUTION:An engine cooling motor fan 6 is driven by a relay 5 on-off controlled by a control unit 9 and when a key switch 1 is connected to on- contact point 2, voltage of a battery is applied to the first input ends of AND- gates 9A, 9B and the relay 5 is controlled by only a water temperature switch 7. When the key switch 1 becomes in off-state,the motor fan 6 is driven through AND-theory of the water temperature switch 7, an atmospheric temperature switch 8 and a voltage detecting switch 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to an engine cooling electric fan control device for an automobile, which is a part of a cooling system for cooling an automobile engine.

[Conventional technology]

Conventionally, there is a control device for an automobile engine cooling electric fan (hereinafter abbreviated as electric fan) of this type, as shown in FIG. In the figure, 1 is a key switch, and this key switch 1 has a built-in on contact 2, and this on contact 2 is for connecting a power source.

Similarly, a starter contact 3 is built into the key switch 1. The starter contact 3 is for detecting whether or not the engine is in a cranking state.

When the key switch 1 is connected to the starter contact 3, it is also connected to the on contact 2 at the same time, which is a two-pole interlocking type.

One end of this key switch 1 is connected to the positive electrode of a battery 4, and the negative electrode of the battery 4 is grounded.

The positive electrode of the battery 4 is grounded via a contact 5b of a relay 5 and an electric fan 6. Relay 5 is this electric 7
This is for driving the antenna 6.

This electric fan 6 is controlled by a control unit 9, and a coil 6a of a relay 6 is connected between a terminal 9f (output end) of the control unit 9 and the positive electrode of the battery 4.

Further, terminals 9a and 9b of the control unit 9 are grounded via a water temperature switch 7 and an ambient temperature switch 8, respectively. The water temperature switch 7 detects the engine cooling water temperature and opens and closes its contacts, and the atmosphere temperature switch 8 detects the temperature of the atmosphere around the engine and opens and closes its contacts.

Terminals 9m and 9b are each AND gate 9A.

9B (both are negative input terminals), and is also connected to the input terminal of the voltage detection switch 10 via the pull-up resistor 14.13, and the output terminal of this voltage detection switch 10 is connected to the AND terminal. It is connected to the fourth input terminal of gate 9B.

Further, the input end of the voltage detection switch 10 is connected to a terminal 9e of the control unit 9.

This terminal 9e is connected to the positive electrode of the battery 4. The power terminals of AND gates 9A, 9B, and OR gate 9C are also connected to the terminal 9e. This terminal 9θ is for supplying power to the inside of the control unit 9, but it is necessary for the control unit 9 to perform control operations even after the power inside the control unit 9 is turned off after the key switch 1 is turned off. It is provided.

The voltage detection switch 10 measures the voltage of the battery 4, and generates an rHJ level signal if it is higher than a predetermined voltage, and an "L" level signal if it is lower than a predetermined voltage.

The first input terminals of the AND gates 9A and 9B are connected to the terminal 9C, and the second input terminal (negative input terminal) of the AND gate 9A is connected to the terminal 9d. AND game) 9B
The second input terminal (negative input terminal) of is connected to the third input terminal of AND game)-9A.

The terminals 9c and 9d are grounded via pull-down resistors 11 and 12 for fixing the rLJ level, respectively. terminal 9
C is connected to the on switch 2, and the terminal 9d is connected to the starter contact 3.

Furthermore, the output terminals of AND game) 9A and 9B are
1st of R gate 9C. It is connected to the second input terminal. O
The output terminal of R game) 9C is connected to the base of transistor 9D. The emitter of transistor 9D is grounded, and the collector is connected to terminal 9f. Terminal 9g is grounded.

Next, the operation will be explained. When the key switch 1 is connected to the on contact 2 and the key switch 1 is turned on, the voltage of the battery 4 is ANDed through the on contact 2 and the terminal 9c.
-9A, 9B, relay 5
Only the water temperature switch 7 is set.
It is controlled by turning on and off the transistor 9b through the logic circuits 9A, 9B SOR'f-to 9C, and if the water temperature is higher than a predetermined temperature, the contact of the water temperature switch 7 is closed and the relay is activated. 5 becomes active, and the electric fan 6 is driven.

Further, if the water temperature is lower than a predetermined temperature, the contacts of the water temperature switch 7 are opened and the electric fan 6 is stopped. However, when the key switch 1 is connected to the starter contact 3 and is in the cranking state, the voltage of the battery 4 is no longer applied to the first input terminals of the AND gates 9A and 9B, regardless of the contact of the water temperature switch 7. Transistor 9b is turned off, relay 5 is also deenergized, and driving of electric fan 6 is unconditionally stopped.

Furthermore, the key switch 1 has an on contact 2 and a starter contact 3.
When the electric fan 6 is not connected to any of the above and is in the off state, the electric fan 6 is driven by the AND logic of the water temperature switch 7, the ambient temperature switch 8, and the voltage detection switch 10.

In other words, only when the water temperature and the atmosphere are higher than the predetermined temperature and the voltage of the battery 4 is higher than the predetermined voltage.
This will drive the electric fan 6.

However, even in this case, when the cranking state is entered, the ON contact 2 and the starter contact 3 of the key switch 1 are connected to the battery 4, and one of the conditions that the key switch 1 is OFF is broken, and the electric fan 6 cannot be driven. Stop.

At the same time, key switch 1 is also turned on, but
Since it is in the cranking state, the electric fan 6 is not driven due to the conditions described above.

[Problem that the invention seeks to solve]

The conventional electric fan control device is configured as described above, and because the control is performed even when the key switch 1 is in the OFF state, the water temperature switch 7 and the atmosphere temperature switch are 8 and the battery 4 are constantly monitored, and a current constantly flows out from the battery 4 as a circuit current to continue monitoring. If left in this state for a long time, the battery 4 will become over-discharged and the terminals of the battery 4 will be The drawback was that the voltage between the two engines decreased, making it extremely difficult to start the engine the next time.

This invention was made to solve these problems, and it suppresses the dark current after the key switch is turned off to an extremely small amount, protects the battery, prevents overheating of equipment around the engine, and also reduces fuel-related equipment. An object of the present invention is to provide an engine cooling electric fan control device for an automobile, which can suppress air bubbles generated in the engine and significantly improve startability in warm conditions.

[Means for solving problems]

After the key switch is turned off, the automotive engine cooling electric fan control device according to the present invention controls the power supply to the control unit until the water temperature drops to a predetermined temperature, and at the same time cuts off the power to the control unit to minimize dark current. A water temperature switch has been inserted to keep the water temperature at a very low level.

[For production]

In this invention, after the key switch is turned off, the contacts of the water temperature switch open and close as the water temperature rises and falls, and in conjunction with this, the control signal to the transistor in the control unit that drives the electric fan drive relay is interrupted. Control the electric fan by, after the key switch off,
When the water temperature falls below a predetermined temperature, the contacts of the water temperature switch remain open, and the power supply line remains cut off even if the water temperature switch is left unused for a long time.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a motor vehicle engine cooling electric fan control device of the present invention will be described based on the drawings.

FIG. 1 is a circuit diagram showing the configuration of one embodiment.

In FIG. 1, when describing the configuration, the same parts as those in FIG. 3 are given the same reference numerals, and the explanation thereof will be omitted, and the parts different from those in FIG. 3 will be mainly described.

As is clear from comparing FIG. 1 with FIG. 3, the water temperature switch 7 is inserted into the power supply line of the control unit 9. That is, the positive electrode of the battery 4 is connected to the terminal 9e via the water temperature switch 7. Accordingly, the terminal 9m and the pull-up resistor 14 are omitted.

Also, AND game) 9A will be powered by two people instead of three, and A
ND Gate 9B has been changed from 4-man power to 3-man power.

The other configurations are the same as in FIG. 3.

The operation shown in FIG. 1 will be explained. When the battery 4 is connected to the ON contact 2 of the key switch 1 and is in the ON state, if the water temperature is higher than a predetermined temperature, the contact of the water temperature switch 7 is closed, and the battery 4 is powered on in the control unit 9. is supplied, the logic circuit of AND gates 9A, 9B, and OR gate 9C turns on transistor 9D,
The relay 5 is driven to drive the electric fan 6.

Furthermore, when the water temperature is lower than a predetermined temperature, the water temperature switch 7 is opened and the power supply line to the control unit 9 is cut off, thereby cutting off the bias voltage of the transistor 9C for driving the relay 5. Then, the driving of the electric fan 6 via the relay 5 is stopped.

However, once the cranking state is entered, the drive of the electric fan 6 is unconditionally stopped as in the prior art.

In addition, in the off state where the voltage of the battery 4 is not applied to either the on contact 2 or the starter contact 3 of the key switch 1, the AND condition of the ambient temperature switch, voltage detection switch, and water temperature switch is applied as in the prior art. , the electric fan is driven.

At this time, the ambient gc temperature around the engine is higher than the predetermined temperature, and the voltage of the battery 4 is also F9? If the voltage is higher than the predetermined water temperature, the control of the electric fan 6 will depend only on the opening and closing of the water temperature switch 7, similar to when the key switch is turned on. The contact becomes open, stopping the drive of the electric fan 6, and also cutting off the power supply line of the control unit 9, which plays a central role in the MAA device of the present invention.

By the way, when key switch 1 is turned off, the engine stops, and the heat source generated by the engine is removed.
The water temperature begins to drop, and from that state, even if the water temperature rises again due to all heat sources in the surroundings, the ambient temperature (for example 50 degrees Celsius)
There is a physical phenomenon that does not exceed (breathing).

In addition, the set temperature (predetermined temperature) of the water temperature switch 7 is very high (for example, 90'C or higher), so once the water temperature reaches the predetermined temperature, the water temperature switch 7 is always in the OFF state and the water temperature switch 7 is turned off again. This state is maintained until the engine is operated, starts generating heat, and imparts thermal energy to the cooling water.

Tip 9: Whether or not to execute the control after turning off the key switch 1 is determined by the water temperature immediately before the key switch 1 is turned off, and furthermore, if the control is executed, the time until the control stops will be longer or shorter depending on the water temperature. Therefore, if the control is stopped, the power supply line to the control unit 9 is cut off, so the outflow current from the battery 4 can be suppressed to a very small amount, and the battery 4 can be protected. By controlling the electric fan after it is turned off, it is possible to suppress overheating of the engine's peripheral equipment and to ensure smooth fuel delivery, thereby significantly improving the next engine startability.

Furthermore, in the above embodiment, the water temperature switch 7 was inserted in series with the power supply line from the battery 4 to the control unit 9 to turn on and off the power, but as shown in FIG. A switching component 15 (for example, a transistor, a relay, etc.) may be provided, which may be controlled by a water temperature switch 7 inserted between the control unit 9 and the ground, and the power supplied to the control unit 9 may be switched on and off.

In addition, the water temperature switch 7 can be inserted not only between the control unit 9 and the ground, but also between the control unit 9, the battery 4, and the positive electrode of the battery if the circuit is configured to drive the power switch 15 in the control unit 9. However, the same effects as in the above embodiment can be achieved.

Furthermore, by providing a timer function in the control unit 9 and controlling after the key switch 1 is turned off only for a certain period of time after the key switch 1 is turned off, a fail-safe function is provided against a short-circuit failure between the contacts of the water temperature switch 7. 9, it is possible to construct a system of very high quality from the standpoint of safety.

〔Effect of the invention〕

As explained above, this invention controls the electric fan by intermittent power supply to the control unit as the water temperature switch opens and closes, so it is possible to reduce the number of circuit components in the control unit, and at the same time, the water temperature If the temperature is lower than a predetermined temperature, the power supply to the control unit is cut off, and the current flowing out from the battery is suppressed to a very small amount, thereby protecting the battery.

Along with this, control after the key switch is turned off becomes possible, suppressing the generation of bubbles in fuel-related equipment, etc. when the engine is warm, and significantly improving the startability of the engine the next time.It is also extremely inexpensive. This has the effect of providing a suitable device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the motor vehicle engine cooling electric fan control device of the present invention, FIG. 2 is a block diagram showing another embodiment of the motor vehicle engine cooling electric fan control device of the present invention, and FIG. The figure is a block diagram of a conventional motor vehicle engine cooling electric fan control device. 1... Key switch, 4... Battery, 5... Relay, 6... Electric fan, 7... Water temperature switch, 8
...Ambient temperature switch, 9...Control unit, 1°...Voltage detection switch. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] A relay for driving the drive control of an automobile engine cooling electric fan, a control unit that controls this relay, and a control unit that is connected to this control unit, detects the temperature of engine cooling water, and controls the control unit according to the detected temperature. An engine cooling electric fan control device for an automobile, characterized in that it is equipped with a water temperature sensor that cuts off the power supply to the control unit when the water temperature falls below a predetermined value after the key switch is turned off.