JPS58211521A - Control circuit for cooling fan of engine for automobile - Google Patents

Abstract

PURPOSE:To cool an engine section effectively without overcooling by detecting an exhaust temperature of the engine and driving a motor fan for cooling the engine section during the time when the exhaust temperature is a set temperature or more. CONSTITUTION:The exhaust temperature is monitored by an exhaust-temperature sensor 9 at all times during the operation of the engine, and a DC voltage signal at a fixed level is outputted to a timer 6 as the exhaust temperature ST from an amplifier 10 when the exhaust temperature reaches the set temperature (such as 700 deg.C) or more. Accordingly, the timer 6 can drive a motor 4 for a time when a fixed time passes (such as 1-3min) after an ignition switch 7 is turned OFF when the switch is turned OFF. A condition conducting the motor 4 is that the ignition switch 7 is turned OFF, and the motor 4 is driven only for a fixed time after the point of time-for example, an exhaust steam turbine is cooled, thus preventing the seizure of a bearing section.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling fan control circuit for a vehicle engine that prevents overcooling of the engine.

As a conventional vehicle engine cooling fan control circuit, 1
For example, there is one shown in Figure @1.

One terminal of a motor 4 that drives a fan is connected to the non-ground electrode of the battery l via a fusible link 2 and a fuse 3, and the other terminal of the motor 4 is grounded via a water temperature switch 5. It is the composition. Water temperature switch 5-digit radiator One theory is that it is installed in the engine cooling water passage, and the contact turns on when the temperature of the engine cooling water exceeds the set temperature.For example, it turns on when the water temperature is 120℃ or higher. It has the following characteristics. The fuse 3 is provided to protect the outside of the battery 1 and the circuit from short-circuit accidents, abnormalities in the motor 4, and the like.

In addition to the configuration described below, the water temperature switch 5 is turned on when the engine cooling water reaches a set temperature or higher. When the water temperature switch 5 is turned on, battery power is supplied to the motor 4, and the motor 4 rotates. This rotation continues until the water temperature switch 5 is turned off, that is, until the temperature of the engine coolant falls below the set value.

However, in conventional vehicle engine cooling fan control circuits, even when the engine speed is high and the cooling capacity is large, such as during high-speed driving or when climbing suddenly,
Since the motor 5 is driven as long as the temperature of the engine cooling water, which is easily affected by the outside temperature, exceeds the set value, the engine is overcooled and the heater core of the air conditioner installed in the heavy vehicle is affected. There is a risk that the temperature of the hot water to be supplied will drop and the heater performance will deteriorate.

The present invention has been developed in view of the above.

To provide a cooling fan control circuit for a vehicle engine that controls a fan motor based on an exhaust temperature that faithfully responds to the engine temperature even though it is not affected by the outside temperature in order to prevent excessive cooling of the engine part. It is.

Below, a cooling fan control circuit for a vehicle engine according to the present invention will be explained in detail.

FIG. 2 shows an embodiment of the present invention.2. The same reference numbers are given to the same oils as in Figure 1. A fusible link 23? is connected to the non-grounded side electrode of battery l. and fuse 3
One terminal of the motor 4 is connected through the terminal, and the other terminal is connected to the control terminal (l) of the timer 6. The timer 6 has a function of controlling the operating time of the motor 4, and its lightning.

The source is lightning, obtained by connecting source terminal B to the output GIIK of fuse 3. Further, the timer 6 is provided with an ignition detection terminal Ig to detect whether the ignition switch 7 is turned off, and the detection terminal Ig is connected to the output side of the ignition switch 7 via a fuse 8 . Further, the timer 6 receives the exhaust In signal St.

This exhaust temperature signal 87 is a detection signal (for example, outputs an ON signal at an exhaust temperature of 7 (11) degrees Celsius) detected by an exhaust temperature sensor 9 (attached to the exhaust manifold) K using a semiconductor temperature-sensing element or the like to the amplifier 10. [Therefore, amplify.

- This is a book that is output as a U-level signal.

k〉The power source of the amplifier 1O is the battery supplied to the timer 6, which is supplied from the WL source terminal B, but is connected so that the power is turned off when the timer 6 ends.

The exhaust temperature sensor 9 constantly monitors the exhaust temperature while the engine is operating.

When the set temperature C (700°C in this example) is detected.

An IF current voltage signal at a constant level is output from the amplifier 10 to the timer 6 as an exhaust temperature signal 8T. The timer 6 allows the motor 4 to be driven only for a certain period of time after the ignition switch 7 is turned off.

The condition for energizing the motor 4 is that the ignition switch 7 is turned off. From that point on, the motor 4 is driven for a certain period of time (for example, 1 minute to 3 minutes) to cool the exhaust turbine. This prevents the bearing from seizing.

As explained above, according to the vehicle engine cooling fan control circuit of the present invention, the cooling fan only operates when the temperature of the engine section is high based on the exhaust temperature, so that the heater performance of the air conditioner is not reduced. The engine part can be effectively cooled without any problems, and the bearings of the exhaust turbine and supercharger can be prevented from seizing when equipped with a turbo device.

Furthermore, the target of temperature detection is low temperature cooling water (up to 12
(approximately 0℃), while the exhaust temperature is high (7(b)℃~
750 degrees Celsius) for a second.

Since the influence of outside temperature can be prevented, variations in fan operation are eliminated, and the fan motor can be effectively controlled without malfunction.

[Brief explanation of the drawing]

FIG. flR1 is a circuit diagram showing a conventional cooling fan control circuit for a vehicle engine, and FIG. 2 is a circuit diagram showing an embodiment of the present invention. l...Battery, 4...Motor. 6... Timer S 7... Ignition switch, 9... Exhaust temperature sensor, 10... Amplifier.

Claims (1)

[Claims] A cooling fan control circuit for a vehicle engine that air-cools an engine part by driving an IL dynamic fan,
An exhaust sensor that outputs an electrical signal according to the engine exhaust temperature. A cooling fan control circuit for a vehicle engine, comprising a control section that drives the electric fan during a period when the exhaust sensor detects a temperature equal to or higher than a set temperature.