JPH0236894Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to a control device for a cooling fan that sends cooling air to a radiator of a vehicle engine. The present invention relates to a cooling control device for a vehicle engine that is capable of controlling a vehicle engine.

(Prior Art) An electric radiator fan is generally used in a cooling device for an automobile engine. In a cooling system equipped with such an electric radiator fan, when the engine cooling water temperature reaches a preset temperature, for example, 90°C or higher, the radiator fan is activated and cooling air is sent to the radiator. , the engine cooling water is cooled.

By the way, while driving a car, the engine cooling water temperature generally rises particularly when the car is idling and when driving at very low speeds. In such a case, the cooling effect of the running wind cannot be expected, and furthermore, as the engine speed decreases, the discharge amount of the water pump also decreases, so the engine temperature tends to rise. Therefore, in the case of an engine cooling system equipped with an electric radiator fan, the radiator fan is often driven during such idling or extremely low speed driving.

In this case, since the power consumption of the radiator fan is relatively large, the voltage of the battery decreases when the radiator fan is driven. Therefore, it is necessary to increase the amount of charge by the engine generator, and the engine load increases. As a result, it is necessary to maintain the engine speed above a certain level even when idling or driving at very low speeds, which becomes an impediment to improving fuel efficiency.

For this reason, conventionally, for example,
As shown in Publication No. 192620, etc., by driving the radiator fan when the vehicle decelerates to lower the engine cooling water temperature, the frequency of operation of the radiator fan is reduced when idling or driving at very low speeds. This is what is being done.
By doing so, the idle work during deceleration of the vehicle is used to drive the engine generator, making it possible to improve fuel efficiency.

Conventionally, when performing this kind of cooling control, even when the vehicle is decelerating, the radiator fan is operated at the same speed as when the engine cooling water temperature is above the set temperature, and the same amount of cooling air is blown. That's what I was doing.

(Problem that the invention aims to solve) However, simply driving the radiator fan during deceleration of the vehicle does not provide sufficient cooling effect during deceleration when the deceleration time is short, such as when driving in a city. Therefore, the radiator fan may have to be operated for a long time even after the engine is idling. Therefore, in such a case, fuel consumption will not be reduced sufficiently.

The present invention has been developed in view of these problems, and its purpose is to provide a sufficient cooling effect in a short period of time when the vehicle is decelerating.

(Means for solving the problem) In order to achieve this objective, in the present invention, cooling air is sent to the radiator as a cooling fan, which blows air in two stages: a steady air flow and a larger air flow. When the vehicle is not decelerating, air is blown at a steady flow rate when the engine coolant temperature rises above the set temperature, and while the vehicle is decelerating, the engine coolant temperature is set to the normal setting. When the temperature is equal to or higher than the second set temperature, which is lower than the temperature, a large amount of air is blown.

In order to switch the air flow rate of the cooling fan, for example, two radiator fans may be installed and one of them may be activated during normal times, while both may be activated during deceleration, or a radiator fan with a large capacity may be used. It may be configured to rotate at a low speed during normal times.

(Function) With this configuration, when the vehicle is decelerating, a large amount of cooling air can be sent to the radiator when the engine cooling water temperature is equal to or higher than the relatively low second set temperature. Therefore, the engine cooling water is sufficiently cooled in a short time.

(Example) Hereinafter, an example of the present invention will be described using the drawings.

In the drawings, FIG. 1 is a circuit diagram showing a first embodiment of a cooling control device for a vehicle engine according to the present invention, which uses a radiator fan and a condenser fan as cooling fans.

A car equipped with an air conditioner has a condenser installed in front of the radiator, and the radiator and condenser are cooled by two cooling fans: a radiator fan and a condenser fan, each driven by a fan motor. Air is being pumped through. Therefore,
The radiator can be cooled by either a radiator fan or a condenser fan. However, condenser fans are generally driven only during cooling. This embodiment makes effective use of the condenser fan.

That is, as shown in FIG. 1, the radiator fan motor 1 that drives the radiator fan includes a normally open type relay switch 2 of the first relay 2.
A voltage is applied from battery B via a. A first water temperature switch 3 is connected in series to a relay coil 2b that opens and closes the relay switch 2a.
When IC ₂ is closed and first water temperature switch 3 is closed, its relay coil 2b is energized. The first water temperature switch 3 is
It is configured to close when the engine cooling water temperature on the radiator side is higher than a first preset temperature, for example 90°C.

On the other hand, a voltage is applied from a battery B to a capacitor fan motor 4 that drives the capacitor fan via a normally open relay switch 5a of a second relay 5. A normally open type relay switch 6a of a cooling operation relay 6 is connected in series to a relay coil _5b that opens and closes the relay switch 5a. When this occurs, the relay coil 5b is energized. Then, the relay coil 6b that opens and closes the relay switch 6a of the cooling operation relay 6 is activated by the electromagnetic clutch 8 according to a command from the air conditioning unit 7.
It is designed to be energized when it is activated. The electromagnetic clutch 8 connects the engine and the compressor to perform cooling.

Further, the relay coil 2b of the first relay 2 and the relay coil 5b of the second relay 5 are connected to output terminals 10 and 11 of the fan control unit 9, respectively.
is also connected. A deceleration state detector 14 and a second water temperature switch 15 are connected to input terminals 12 and 13 of the fan control unit 9, respectively.

The deceleration state detector 14 generates a high-level deceleration signal when the vehicle is in a deceleration state.
In this case, if the vehicle is equipped with a manual transmission, the deceleration signal is determined by the negative pressure Pb detected by a negative pressure port that is always opened downstream of the throttle valve in the engine intake system, for example, being 580 mmHg or more. , and is detected by a negative pressure port that opens at a position downstream of the throttle valve when the throttle valve is opened above a certain opening degree, and upstream from the throttle valve when the throttle valve is closed below a certain opening degree. When the negative pressure Pc is 50 mmHg or less and the engine speed is 1600 rpm or more for a certain period of time, it is generated continuously for at least a certain period of time, and if the vehicle is equipped with an automatic transmission, for example, the vehicle speed is When the speed is 15 km/h or more and the negative pressure Pc near the throttle valve is 50 mmHg or less for a certain period of time, it is continuously generated for at least a certain period of time.

The second water temperature switch 15 generates a high level signal when the engine cooling water temperature on the cylinder head side is higher than a preset second set temperature. The second set temperature is set lower than the first set temperature, for example, 75°C.

Inside the fan control unit 9, its input terminals 12 and 13 are both connected to the input section of an AND circuit 16. The output signal of the AND circuit 16 is guided to the base of the transistor 17. The collector of the transistor 17 is connected to the output terminal 11 on the second relay 5 side, and is also connected via the diode 18 to the output terminal 10 on the first relay 2 side. Further, the emitter of the transistor 17 is grounded.

Next, the operation of the cooling control device configured as described above will be explained.

When the engine is running, the ignition switch
IG ₂ is closed. When the vehicle is not in a deceleration state, the signal input from the deceleration state detector 14 to the AND circuit 16 is at a low level, so the output signal of the AND circuit 16 is also held at a low level. Transistor 17 is therefore cut off.

In this state, when the engine cooling water temperature reaches the first set temperature of 90° C. or higher, the first water temperature switch 3 closes. Then, the relay coil 2b of the first relay 2 is excited, and the relay switch 2a is closed. As a result, the radiator fan motor 1 is driven,
Cooling air is sent to the radiator by the radiator fan. The amount of air blown at this time is the same steady amount of air blown as during normal cooling.

Furthermore, when cooling the vehicle interior, the relay coil 6b of the cooling operation relay 6 is energized by a command from the air conditioning unit 7. Thereby, the relay switch 6a is closed and the relay coil 5b of the second relay 5 is energized. At the same time, diode 1
8 and relay switch 6a, the first
Relay coil 2b of relay 2 is also excited. Therefore, at this time, the first and second relays 2 and 5
The relay switches 2a and 5a are both closed, and the radiator fan motor 1 and the condenser fan motor 4 are driven simultaneously. Thus, a large amount of cooling air is delivered by the radiator fan and condenser fan to cool the radiator and condenser.

If the vehicle enters a deceleration state when air conditioning is not being performed and the deceleration state continues for a certain period of time,
A high level signal is input from the deceleration state detector 14 to the AND circuit 16. At this time, if the engine cooling water temperature is higher than the second set temperature of 75℃, the second
A high level signal is also input from the water temperature switch 15 to the AND circuit 16. Therefore, the output signal of the AND circuit 16 becomes high level, and the transistor 17 becomes conductive. As a result, the relay coils 2b, 5b of the first and second relays 2, 5 are grounded via the transistor 17, and both of the relay coils 2b, 5b are excited.
In this way, the radiator fan motor 1 and the condenser fan motor 4 are driven simultaneously. Therefore, at this time, cooling air is sent to the radiator from the two cooling fans, the radiator fan and the condenser fan, and the amount of air blown is large, which is larger than the steady air amount.

In this manner, when the vehicle decelerates, a large amount of air is blown to the radiator, thereby rapidly cooling the engine cooling water. Therefore, even if the deceleration time is short, a sufficient cooling effect can be obtained. At this time, the load on the engine generator increases to drive the fan motors 1 and 4, but since the idle work during deceleration is used to drive the engine generator, an increase in fuel consumption is prevented.

By cooling the engine cooling water sufficiently when the vehicle decelerates, the temperature of the engine cooling water is less likely to exceed 90°C during idling or when driving at very low speeds, which reduces the chance of the radiator fan being driven. frequency decreases. Therefore, fuel efficiency is improved, and the time during which noise is generated due to fan operation is also shortened.

During deceleration of the vehicle, when the engine cooling water temperature drops to 75° C. or lower, the signal from the second water temperature switch 15 becomes low level, and the drive of the fan motors 1 and 4 is stopped. This prevents overcooling of the engine. Furthermore, when deceleration is stopped, the driving of the fan motors 1 and 4 is also stopped. however,
At that time, if the engine cooling water temperature is 90° C. or higher, only the radiator fan motor 1 is driven.

In this way, in this embodiment, when the vehicle is not in a deceleration state, only the radiator fan is driven when the engine cooling water temperature is higher than the first set temperature of 90 degrees Celsius, and the constant air flow rate to the radiator is controlled. While the vehicle is decelerating, the radiator fan and condenser fan are simultaneously driven when the engine cooling water temperature is above the second set temperature of 75°C, which is relatively low, and a large amount of air is blown to the radiator. ventilation is performed. Therefore,
In this embodiment, two fans, a radiator fan and a condenser fan, constitute a cooling fan that can switch the air flow rate in two stages, and a fan control unit 9 sends control signals for the cooling fan. This is the control circuit that generates the electricity.

FIG. 2 is a circuit diagram showing a second embodiment of the cooling control device according to the present invention.

As is clear from this figure, in this embodiment, only the radiator fan is used as the cooling fan that sends cooling air to the radiator.
This radiator fan is said to have a larger capacity than normal ones. A voltage is applied to the radiator fan motor 1 that drives the radiator fan from the battery B via the relay switch 2a of the first relay 2 or the relay switch 5a of the second relay 5, which are provided in parallel. It's summery. A resistor 20 is connected in series to the relay switch 2a of the first relay 2.

The relay coil 2b that opens and closes the relay switch 2a of the first relay 2 is connected in series with the first water temperature switch 3, and when the ignition switch IG ₂ is closed and the first water temperature switch 3 is closed, , the relay coil 2b is energized. The first water temperature switch 3 is configured to close when the engine cooling water temperature on the radiator side is higher than a first set temperature, for example, 90°C.

The relay coil 5b that opens and closes the relay switch 5a of the second relay 5 is energized when a high-level signal is output from the AND circuit 21 forming the control circuit. The AND circuit 21 includes a deceleration state detector 14 and a second water temperature switch 1.
The signal from 5 is input. These deceleration state detector 14 and second water temperature switch 1
5 is similar to the embodiment shown in FIG.

In the cooling control device configured in this manner, when the engine cooling water temperature reaches the first set temperature of 90°C or higher when the vehicle is not in a deceleration state, the first water temperature switch 3 closes and the first relay 2 Coil 2b is excited. Therefore, the first relay 2
The relay switch 2a is closed and the fan motor 1 is driven. At this time, since battery voltage is applied to the fan motor 1 via the resistor 20, the fan motor 1 rotates at a relatively low speed. As a result, even though the radiator fan has a large capacity, the power required to drive it can be made to be about the same as that of a normal radiator fan.

Thus, at this time, cooling air is sent to the radiator at a constant flow rate.

When the vehicle enters a deceleration state, the deceleration state detector 14
A high-level signal is input to the AND circuit 21 from the . At this time, if the engine cooling water temperature is equal to or higher than the second set temperature of 75° C., a high level signal is also input from the second water temperature switch 15 to the AND circuit 21. Therefore, a high level signal is output from the AND circuit 21, and the relay coil 5b of the second relay 5 is excited. As a result, the relay switch 5a of the second relay 5 is closed, and the fan motor 1 is driven. At this time, since the battery voltage is directly applied to the fan motor 1, the fan motor 1 rotates at high speed.

Thus, when the vehicle is decelerating, the large-capacity radiator fan is rotated at high speed, and a large amount of cooling air is sent to the radiator.

Therefore, the same effects as in FIG. 1 can be obtained.

FIG. 3 is a circuit diagram showing a third embodiment of the cooling control device according to the present invention.

As is clear from this figure, the cooling control device of this embodiment is constructed almost the same as the embodiment of FIG. 2. However, in the case of this embodiment, a resistor 20 is connected to the circuit on the relay switch 2a side of the first relay 2.
Instead of providing the circuit, the number of brushes of the radiator fan motor 1 is made different between that circuit and the circuit on the relay switch 5a side of the second relay 5, and the first relay 2
When voltage is applied from the side, the second relay 5
Fan motor 1 when voltage is applied from the side
is rotated at low speed.

Therefore, even in the cooling control device configured in this way, when the vehicle is not in a deceleration state,
When the engine cooling water temperature is higher than the first set temperature of 90° C. set in the first water temperature switch 3, the fan motor 1 is rotated at a low speed, and the radiator fan blows air at a constant air flow rate. Furthermore, while the vehicle is decelerating, when the engine cooling water temperature is higher than the second set temperature of 75°C set in the second water temperature switch 15, the fan motor 1 is rotated at high speed, and the radiator fan generates a large amount of air. Air is blown.

In this way, in any of the embodiments, a sufficient cooling effect can be obtained in a short time when the vehicle is decelerated.

In the above embodiment, two water temperature switches, the first water temperature switch 3 and the second water temperature switch 15, are used as the water temperature detectors for detecting the engine cooling water temperature, and each of the water temperature switches determines the engine cooling water temperature. For example, one thermistor is used as the water temperature detector, and the detected value is compared with the first or second set temperature using a comparator. It is also possible to perform a similar operation.

(Effect of the invention) As is clear from the above explanation, according to the invention, when the vehicle is not in a deceleration state, the engine is supplied with a steady air flow rate when the engine cooling water temperature is equal to or higher than the first set temperature. Cooling air is sent to the radiator at a large air flow rate when the engine cooling water temperature is above the relatively low second set temperature while the vehicle is decelerating, so the deceleration time is shortened. Even if this happens, the engine cooling water temperature can be sufficiently lowered during deceleration. Therefore, the number of times or time required to drive a cooling fan such as a radiator fan is further reduced during idling after deceleration or when driving at very low speeds, and the total load on the engine is reduced. In this way, it becomes possible to improve fuel efficiency.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing one embodiment of the cooling control device for a vehicle engine according to the present invention, FIG. 2 is a circuit diagram showing another embodiment of the cooling control device according to the present invention, and FIG. FIG. 3 is a circuit diagram showing still another embodiment of the cooling control device according to the present invention. 1...Radiator fan motor, 3...First water temperature switch (water temperature detector), 4...Condenser fan motor, 9...Fan control unit (control circuit), 14...Deceleration state detector, 15...
2nd water temperature switch (water temperature detector), 21...AND circuit (control circuit).

Claims (1)

[Scope of claim for utility model registration] A water temperature detector that detects the engine cooling water temperature, a deceleration state detector that detects the deceleration state of the vehicle, and a radiator that provides cooling in two stages: a steady air flow rate and a larger air flow rate. a cooling fan that can send air; and when the vehicle is not in a deceleration state, the cooling fan is driven so that air is blown at the steady air flow rate when the engine cooling water temperature is higher than a first preset temperature. At the same time, during deceleration of the vehicle, the cooling fan is driven so that air is blown at the large air flow rate when the engine cooling water temperature is equal to or higher than a second set temperature that is set lower than the first set temperature. A cooling control device for a vehicle engine, comprising: a control circuit that generates a signal;