JPS6380011A - Controller of electric motor-driven cooling fan of internal combustion engine - Google Patents

Abstract

PURPOSE:To improve the acceleration ability of the cooling fan in the title without generating any overheat by stopping the electric motor-driven cooling fan for a period of appropriate fuel injection times when the engine temperature is lower than a prescribed value. CONSTITUTION:An electronic control unit 17 turns on a cooling fan switch 16 when the engine temperature is more than a normal temperature based on the detected value of a temperature sensor 8 for detecting the engine temperature and drives a cooling fan 12. However, when the engine temperature is lower than the set temperature which is higher than the normal temperature by a prescribed range of temperature and change speed of the opening degree of a throttle in the opening direction based on the detected value of a throttle sensor 11 is more than a prescribed value or change amount of intake pressure per unit time based on the detected value of an intake pressure sensor 9 is less than a prescribed value, it is judged as an acceleration state and a cooling fan 12 is stopped for a period of the prescribed fuel injection times.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for controlling an electric cooling fan for a water-cooled internal combustion engine in accordance with the operating state of the internal combustion engine.

[Conventional technology]

Cooling fans for internal combustion engines include those that are constantly driven to rotate by power transmission from the internal combustion engine, and those that are driven to rotate by an electric motor that is connected to a battery that is charged by a generator that is driven by the internal combustion engine. However, the rotation speed of the latter electric cooling fan must be set to a relatively high value so as not to cause overheating even under the worst conditions in an internal combustion engine. Since this is maintained even in the idling operating range of the internal combustion engine, not only overcooling occurs in the idling operating range, but also noise and vibration increase.

Therefore, Japanese Patent Application Laid-open No. 59-32613 as a prior art proposes to link an electric cooling fan and a throttle valve in an internal combustion engine so that when the throttle valve is closed, the number of rotations of the cooling fan decreases. ing.

[Problem that the invention seeks to solve]

However, the battery for this electric fan is constantly charged by a generator driven by the internal combustion engine, and driving the electric cooling fan adds a load to the internal combustion engine. The prior art only slows down the electric cooling fan according to the opening degree of the throttle valve in the internal combustion engine;
During acceleration with a large opening of the throttle valve, the engine remains at a high rotational speed, so the acceleration of the internal combustion engine is reduced due to the drive of the electric cooling fan, and the fuel consumption is also reduced. The amount also increased.

The present invention improves acceleration and reduces fuel consumption by reducing the load on the electric cooling fan when accelerating the internal combustion engine when an electric cooling fan is used as a cooling fan in a fuel-injected internal combustion engine. The purpose is to reduce the

[Means for solving problems]

In order to achieve this object, the present invention provides an electric cooling fan connected to a battery that is charged by a generator driven by a fuel-injected internal combustion engine. a cooling fan control means configured to cut off power to the electric cooling fan only for a certain period of time, and prohibit control by the cooling fan control means when the internal combustion engine reaches a temperature higher than a normal temperature by an appropriate temperature. The configuration includes a means to do this.

[Action/effect of the invention]

With this configuration, when accelerating by opening the throttle valve, etc., it is possible to automatically stop driving the electric cooling fan for the appropriate number of fuel injections. The load for driving the fan will be removed. On the other hand, when the temperature of the internal combustion engine reaches an appropriate amount higher than the normal temperature, the control to stop the electric cooling fan when the internal combustion engine accelerates as described above is prohibited, and the electric cooling fan is constantly driven. Therefore, it is possible to reliably prevent overheating in the internal combustion engine.

Therefore, according to the present invention, it is possible to prevent the electric cooling fan from becoming a load when accelerating the internal combustion engine while the internal combustion engine is not overheated, thereby improving the acceleration performance of the internal combustion engine. , has the effect of reducing fuel consumption.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, reference numeral 1 indicates a multi-cylinder internal combustion engine mounted on an automobile (not shown). An intake passage 4 with a valve 5 is connected thereto, and a fuel injection valve 6 is provided for each cylinder.

The internal combustion engine 1 includes a rotation sensor 7 for detecting the rotational speed of the crankshaft in the internal combustion engine 1 and a temperature sensor 8 for detecting the temperature. An intake pressure sensor 9 for detecting the intake pressure on the side, and an idle switch 10 on the throttle valve 5 that is turned on when the throttle valve 5 is closed (idle opening);
Throttle sensor 11 for detecting the opening degree in
are provided for each.

Further, in the figure, reference numeral 12 indicates an electric cooling fan for ventilating the radiator 13 for the internal combustion engine 1, and the electric cooling fan 12 is connected to a generator (not shown) that is constantly driven by the internal combustion engine 1. ) is connected via an electric circuit 15 to a battery 14 that is charged by the electric cooling fan 12.
- A cooling fan switch 16 is provided to turn off the cooling fan.

Reference numeral 17 in the figure indicates the rotation sensor 7 and the temperature sensor 8.
, an electronic control unit for controlling fuel injection from each of the fuel injection valves 6 and controlling the cooling fan switch 16 by inputting signals from the intake pressure sensor 9, the idle switch 10, and the throttle sensor 11. show.

This electronic control unit 12 has a built-in ROM that stores the basic injection amount as a two-dimensional map using the intake pressure downstream of the throttle valve 5 and the engine rotational speed as parameters, and stores the basic injection amount from the fuel injection valve 6 for each cylinder. Fuel injection amount,
The fuel injection amount is read from the two-dimensional map based on the rotation speed detected by the rotation sensor 7 and the intake pressure detected by the intake pressure sensor 9, and fuel injection is performed every revolution of the engine. It has a main routine.

Furthermore, this electronic control unit 12 is provided with an interrupt routine as shown in the flowchart shown in FIG. 2 in the middle of the main routine.

That is, first, in step S1, it is determined whether the temperature in the internal combustion engine 1 exceeds a temperature higher by an appropriate temperature dT (for example, 100 °C) than the normal temperature T (for example, 80 to 85 °C), and '+dT is not exceeded, the process moves to step S2, and it is determined whether the idle switch 10 is ON, that is, the throttle valve 5 is closed. If the throttle valve 5 is not closed, the process moves to step S3. It is determined whether the change amount dPM of the intake pressure P per unit time is negative or not, that is, whether the intake pressure P is decreasing.If the intake pressure is not decreasing (in other words, the intake pressure is high) ), the process moves to step S4, where the opening degree dT of the throttle valve 5 per unit time is determined.
It is determined whether A is negative or not, that is, whether or not the throttle valve 5 is turned in the closing direction. If the throttle valve 5 is not turned in the closing direction (that is, whether the throttle valve 5 is turned in the opening direction If it is moving), the process moves to the next step S5.

Then, in step S5, it is determined whether or not the throttle valve 5 is opened more than the previous time, and if the throttle valve 5 is opened more than the previous time, in step S6, it is determined whether or not the throttle valve 5 is opened more than the previous time. Appropriate number of times set
(For example, 10 times) is counted by subtracting one by one.

Further, even when it is determined in step S5 that the throttle valve 5 is not opened as compared to the previous time, the amount of change dPM of the intake pressure P per unit time is reduced to the predetermined value by 1.
If it exceeds dPM (where K1 is a constant), it is determined that the internal combustion engine is accelerating, so the process moves to step S6 through step S7, and the throttle valve 5 is opened more than before in step S5. Even if it is determined that the opening degree dTA of the throttle valve 5 per unit time is less than the predetermined value by 2. If it exceeds dTA (where K2 is a constant), it is determined that the internal combustion engine is also accelerating, and the process proceeds from step S8 to step S6.

Then, in the next step S9, it is determined whether or not the N is zero, and when N≠0, the cooling fan switch 16 is turned OFF (step 510), but when N=O
At this time, the cooling fan switch 16 is turned on (step 511).

Through this series of flows, the throttle valve 5 is opened,
The change amount per unit time of the intake pressure P is greater than or equal to a predetermined value in the positive direction, or the opening degree of the throttle valve 5 per unit time is greater than or equal to the predetermined value in the opening direction. The drive of the electric cooling fan 12 can be automatically stopped for a time corresponding to the number of fuel injections N.

On the other hand, in step S1, the temperature of the internal combustion engine is T
If it exceeds +dT, N is set to zero in step S12, and then the process proceeds to step S9, thereby stopping the driving of the electric cooling fan 12 when the internal combustion engine accelerates as described above. In addition, when the idle switch 10 is ON in step S2, the intake pressure P is prohibited in step S3.
When the amount of change dPM per unit time is negative, and also when the opening degree dTA of the throttle valve 5 per unit time is negative in step S4, the process moves to step S12, so that when the internal combustion engine is accelerated, In this case, control to stop driving the electric cooling fan 12 is prohibited.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is a flowchart. DESCRIPTION OF SYMBOLS 1...Fuel injection type internal combustion engine, 2...Intake manifold, 3...Air cleaner, 4...Intake passage, 5...Throttle valve, 6...Fuel injection valve ,7
...Rotation sensor, 8...Temperature sensor, 9.
... Intake pressure sensor, 10 ... Idle switch, 11 ... Throttle sensor, 12 ... Electric cooling fan, 13 ... Radiator, 14 ...
Battery, 15... Electric circuit, 16... Cooling fan switch, 17... Electronic control unit. Patent applicant Daihatsu Motor Co., Ltd. Figure 1

Claims (1)

[Claims] (1) In an electric cooling fan connected to a battery that is charged by a generator driven by a fuel-injected internal combustion engine, the electric cooling fan Cooling fan control means configured to cut off power supply to the cooling fan, and means for prohibiting control by the cooling fan control means when the temperature of the internal combustion engine reaches an appropriate temperature higher than the normal temperature. A control device for an electric cooling fan in an internal combustion engine, characterized by: