JPH0333900B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling fan control device for an internal combustion engine installed in an automobile or the like.

In order to improve the fuel efficiency of an internal combustion engine, it is desirable to omit the horsepower consumption of the cooling fan as much as possible. Therefore, in recent years, for example, a hydraulic fan clutch as shown in Fig. 1 has been installed in the power transmission path from the crankshaft to the cooling fan to prevent the cooling fan from being driven unnecessarily. was.

As is well known in the past, the hydraulic fan clutch shown in Fig. 1 has a drive disk 2 fixed to a shaft 1 connected to the engine's crankshaft, and the cooling fan is attached with bolts or the like. The tightened and fixed clutch case 3 is attached to the shaft 1.
The drive disk 2 is housed in a torque transmission chamber 4 formed in the case 3 by being pivotally attached to the case 3. Then, oil such as silicone oil is filled into the oil reservoir chamber 6 separated from the torque transmission chamber 4 via the separate plate 5, and the bimetal 7 attached to the front surface of the case 3 and the port 8 of the separate plate 5 are opened and closed. By interlocking the valve plate 9 with the piston 10, the valve plate 9 is brought into contact with and separated from the separate plate 5 according to the temperature of the outside air (air) after passing through the radiator, thereby changing the opening degree of the port 8. Torque transmission chamber 4
The number of rotations of the cooling fan was automatically adjusted by increasing or decreasing the amount of oil inside the fan, and by variable control of the transmitted torque.

However, with such a fluid-type fan clutch, the torque transmitted to the cooling fan cannot be made zero, so even when cooling is not required, the fan swings, consuming engine horsepower. In addition, since the transmitted torque is controlled only by the outside air temperature after passing through the radiator, the control characteristics of the cooling fan are restricted and the control accuracy is poor.Also, since the structure is essentially sealed, maintenance of bearings, etc. is required. There was an inconvenience that the workability was poor when performing this method.

On the other hand, in order to improve engine warm-up performance, etc., as seen in Utility Model Application Publication No. 56-20028, a slip-coupling is inserted in the torque transmission path, and the rotation of the cooling fan is mechanically controlled. Some are equipped with a stopper that can prevent this. Although this case has the advantage of being able to prevent the cooling fan from spinning, it still cannot be said that the fuel efficiency has been sufficiently improved.

The present invention has been made in view of the above-mentioned problems, and is capable of overheating the cooling fan by disconnecting and connecting (hereinafter referred to as ON/OFF) the fan clutch according to the fan water temperature, rotational speed, and rotational acceleration of the engine. Drive without shortage to prevent wasting power due to unnecessary rotation,
The purpose is to improve fuel efficiency and warm-up characteristics at the same time.

The present invention will be explained in detail below based on an embodiment shown in FIGS. 2 to 7.

FIG. 2 is an overall configuration diagram showing an embodiment of the present invention;
FIG. 3 is a sectional view of the fan clutch, in which a pulley 13 is fixed to the shaft end of the crankshaft 12 of the internal combustion engine 11, and the pulley of the fan clutch 16 is attached to the engine 11 via a bracket 14 and a support shaft 15. A belt (not shown) is stretched between the pulley 17 and the pulley 13 to cause the pulleys 13 and 17 to interlock.

Further, a case 19 to which a cooling fan 18 is fixed is pivotally attached to the support shaft 15, and a piston 20 mounted on the case 19 is brought into contact with a drive disk 21 fixed to the pulley 17. A pressure chamber 22 formed by the piston 20 and the case 19
and an air tank 23 formed on the support shaft 15.
4 and the solenoid valve 25. When the solenoid valve 25 is opened and air is sent into the pressure chamber 22, the piston 20 moves to the left in the figure against the return spring 26, and the drive disk 21 and then,
Torque is transmitted from the pulley 17 to the cooling fan (case) via the drive disk 21 and piston 20. 27 is a bearing,
28 is an air inlet.

Meanwhile, turn on/off the solenoid valve 25.
The controller 29 that controls the ON/OFF operation of the fan clutch 16 includes water temperature sensors 30 and 31 provided at the cooling water inlet and outlet of the engine 11, and detects the rotation speed of a rotating part that is synchronized with the rotation of the crankshaft. Each output from the rotation sensor 32 is supplied. 33 and 34 are a warning buzzer and a warning lamp connected to the abnormality output terminal of the controller 29.

The controller 29 is configured as shown in FIG.
is supplied to the condition determination circuit 35, and the rotation sensor 32
The signal output from the motor is converted into a rotational speed N by an F-V converter 36, and this is supplied to a condition determination circuit 35. Further, the output of the F-V converter 36, that is, the rotational acceleration α obtained by supplying the engine speed N to the differentiating circuit 37, is similarly supplied to the condition determination circuit 35, and the output of the condition determination circuit 35 is It is supplied to the solenoid valve 25 via the solenoid valve control circuit 38. 39 is the warning buzzer 33
and a warning circuit that operates the warning lamp 34; 40 is a power supply circuit;

The condition determination circuit 35 processes each signal according to the flowchart shown in FIG. 5 and turns the signal to the solenoid valve control circuit 38 ON/OFF.
Control.

That is, first, when a failure or disconnection occurs in the solenoid valve 25, each sensor 30, 31, 32, etc., the warning circuit is activated to turn on the warning buzzer 33. Also, when the coolant outlet temperature Two is higher than T ₆ (for example, 110°C), it is determined that overheating is occurring and the buzzer and lamp are turned on. In addition, these buzzers and lamps are
It is manually returned to the OFF state, but in the event of overheating as described above, the fan clutch is directly activated by manual operation.

When the cooling water outlet temperature Two is higher than T ₅ (for example, 90°C), the solenoid valve 25 is turned on. When the outlet temperature Two is lower than _T5 , the difference between the inlet temperature Twi and the outlet temperature Two is determined, and when this difference is higher than a certain value, the outlet temperature Two is compared with _T4 (for example, 70°C). Then, when Two≧T ₄ , the engine rotation speed N is compared with N ₁ (for example, 600 rpm), and when N≧N ₁ is not, that is, if it is determined that the engine is running at idle, it outputs ON. . Also, when N≧N ₁ , it is determined that the operating state is normal, and the rotational acceleration α is compared with a constant value α ₁ , and when α≧α ₁ is not, that is, when the operation is steady, the ON and conversely,
When α≧ _α1 , it temporarily outputs OFF. Then, after _t1 seconds, the engine speed N is again compared with a constant value _N2 (for example, 2000 rpm), and if N≦ _N2 , an ON signal is output, but if N> _N2 , an OFF signal is output.

In other words, when the engine speed is higher than _N2 , it is determined that the car is being driven at high speed, and the fan is stopped to maximize cooling by natural ventilation, improving fuel efficiency. When the temperature of the engine cooling water becomes higher than _T5 , the solenoid valve 25 is turned on, the fan clutch 16 is turned on, and the cooling fan 18 is driven.

On the other hand, engine cooling water inlet temperature Twi and outlet temperature
When the difference from Two is lower than a constant value T ₀ , the outlet temperature
Compare Two with T ₂ and T ₁ respectively, and compare T ₂ (e.g. 55
℃), it is assumed that warm-up has been completed and control is returned to the rotational speed and rotational acceleration. Also, if the outlet temperature Two is below T ₁ (for example 45℃),
It outputs OFF, and when it is higher than T ₁ , it checks whether the outlet temperature Two is rising, and if it is rising, it determines that it is warming up and outputs OFF. still,
When Two is not rising, it is determined that the operation is at high speed and light load, such as when descending, and control is returned to the rotational speed and rotational acceleration. Similarly, when the outlet temperature Two is lower than T ₄ , it is compared with T ₃ , and if it is below T ₃ (for example, 60℃), OFF is output, but if it is higher than T ₃ and
When Two is not even rising, it is determined that it is high-speed light load operation as described above, and control is returned to the rotational speed and rotational acceleration, and when it is rising, OFF is output.

Therefore, for the outlet temperature Two of the engine cooling water and the difference T ₀ between the outlet temperature Two and the inlet temperature Twi, the fan clutch is turned on and off as shown in FIG.
It is controlled OFF, and the rotational acceleration and rotational speed are controlled ON/OFF with the characteristics shown in FIG.

In the embodiment, the fan clutch is an air-operated clutch, but it may also be a hydraulic or electromagnetic clutch. Furthermore, the cooling water temperature does not necessarily have to be detected at both the inlet and outlet; for example, only the outlet temperature may be detected to simplify the control.

As explained above, according to the present invention, the temperature is determined not only by the temperature of the air that has passed through the radiator as in the past, but also by the temperature of the cooling water at the outlet of the engine body, which reflects the engine temperature, the rotational speed, and the rotational acceleration. Since the fan clutch is turned ON and OFF, the load on the cooling fan can be reduced when the cooling capacity increases due to driving wind or natural ventilation, and the fan clutch can be turned OFF when the cooling fan is not required. Since it is also possible to prevent the cooling fan from spinning, engine warm-up characteristics and fuel efficiency are greatly improved.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an example of a conventional fan clutch, FIG. 2 is an overall configuration diagram of an embodiment of the present invention, FIG. 3 is a sectional view of a specific example of the fan clutch shown in FIG. The controller block diagram, Figure 5 is the controller flowchart, Figures 6 and 7 are the ON/OFF state of the cooling fan (fan clutch).
It is an OFF characteristic diagram. 10... Internal combustion engine, 16... Fan clutch, 18
...Cooling fan, 29...Controller, 30, 31
...Water temperature sensor, 32...Rotation sensor.

Claims (1)

[Claims] 1 At least a means for detecting the cooling water temperature at the outlet of the engine body, a means for detecting the rotational speed of the engine, a means for detecting the rotational acceleration of the engine based on the rotational speed signal detected through the means, and each of these. Based on the engine cooling water temperature, rotational speed, and rotational acceleration obtained by the means, when the engine cooling water temperature is above a predetermined value, a fan clutch is connected that connects and disconnects the engine body and the cooling fan regardless of the rotational speed and rotational acceleration. and means for controlling the fan clutch to connect and disconnect when the engine cooling water temperature is lower than the predetermined value, in accordance with the engine operating state based on the engine cooling water temperature, the rotational speed, and the rotational acceleration. cooling fan control device.