JP2531196B2 - Rotational speed control device for cooling fan of internal combustion engine for vehicle - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation speed control device for a cooling fan of an internal combustion engine used in a vehicle such as an automobile, and particularly to an electric or hydraulically driven variable speed cooling fan. Related to the rotation speed control device.

2. Description of the Related Art In an internal combustion engine used in a vehicle such as an automobile, a cooling fan that supplies cooling air to an engine cooling radiator is driven by an electric motor or a hydraulic motor such as a hydraulic motor, and the rotation speed thereof is the cooling water temperature and the vehicle speed. It is already known to control in accordance with
JP-A-58-13119 and JP-A-61-21826.

The cooling fan is preferably rotated at a high speed for cooling the cooling water, but as the cooling fan is rotated at a higher speed, the fan noise increases and the quietness in the passenger compartment deteriorates. In vehicles such as automobiles, in addition to fan noise, engine rotation noise is another noise that contributes to the quietness of the passenger compartment. When the noise level due to this engine rotation noise is high, fan noise is not noticeable The noise level of the cooling fan is noticeable when the noise level is low.The cooling fan speed is controlled according to the engine speed so that the noise level does not exceed the noise level of the engine. It has already been proposed only to forcibly rotate the cooling fan at a high speed in order to avoid overheating, which is disclosed, for example, in Japanese Utility Model Publication No. 55-165941.

Problems to be Solved by the Invention Apart from the problem of fan noise when the temperature of the cooling water is low, the cooling fan cannot be operated at high speed from the viewpoint of supercooling. However, in the conventional cooling fan rotation speed control device as described above, the cooling fan does not depend on the temperature of the cooling water until the cooling water temperature reaches a high temperature at which overheating may occur. Controlled accordingly,
Even if the problem of fan noise is solved, the cooling fan may rotate more than necessary with respect to the cooling water temperature, and the internal combustion engine may be overcooled.

Also, in the hydraulic drive type, in the type in which the hydraulic pump that supplies the hydraulic pressure to the fan driving hydraulic motor is directly driven by the shaft output of the internal combustion engine, the engine speed is a certain value. It is considered that the output hydraulic pressure of the hydraulic pump is configured to reach the rated relief pressure only after reaching the point. In this case, the output hydraulic pressure of the hydraulic pump increases in accordance with the increase of the engine speed until the engine speed reaches a predetermined value, so that the maximum possible value of the fan speed is naturally proportional to the engine speed. This is a significant control characteristic from the viewpoint of reducing fan noise in terms of the balance between engine noise and fan noise. When the engine speed decreases due to the deceleration operation, the fan noise will be annoying unless the fan speed also decreases accordingly. For this reason, the fan speed decreases rapidly as the engine speed decreases. Should be. However, in the structure as described above, when the engine speed is above the predetermined value during deceleration, that is, when the output hydraulic pressure of the hydraulic pump is equivalent to the relief pressure, the engine speed is kept below the predetermined value. Since the output hydraulic pressure of the hydraulic pump does not change even if the engine speed decreases,
The fan speed does not decrease, and therefore fan noise during deceleration becomes a new problem.

In view of the above problems, the present invention has been improved in which the rotation speed of the cooling fan is always controlled from the viewpoint of both the temperature of the cooling water and the fan noise, and the proper cooling of the internal combustion engine and the reduction of the fan noise are both achieved. An object is to provide a rotation speed control device for a cooling fan.

According to the present invention, there are provided a cooling water temperature detecting means for detecting a temperature of cooling water for cooling an engine, a blower motor rotation speed for indoor blower, an intake air amount, and a vehicle speed. , Noise generation factor state detection means for detecting the state of a factor that causes noise, such as engine speed, and control to increase the cooling fan speed in response to an increase in the cooling water temperature detected by the cooling water temperature detection means Cooling water temperature-corresponding fan rotation speed determining means for determining a target rotation speed, and noise generation factor correspondence for determining a fan rotation speed upper limit value that increases in accordance with an increase in the noise generation factor detected by the noise generation factor state detection means Determined by the fan rotation speed upper limit value determining means, the control target rotation speed determined by the cooling water temperature corresponding fan rotation speed determining means, and the noise generation factor corresponding fan rotation speed upper limit value determining means A final fan rotation speed determining means for determining a cooling fan rotation speed based on the smaller rotation speed of the fan rotation speed upper limit value determined above, and a fan rotation speed determined by the final fan rotation speed determining means. And a cooling fan rotation speed control unit for controlling the rotation speed of the cooling fan.

According to the above-described configuration, when the cooling water temperature is low, the cooling fan rotation speed is kept low from the cooling water temperature at that time even when the cooling fan rotation speed may be increased from the viewpoint of fan noise. Overcooling of the internal combustion engine is avoided by virtue of this, and even if the cooling water temperature is high, it is necessary to keep the cooling fan rotation speed low from the viewpoint of fan noise. Both supercooling of the engine and reduction of fan noise are achieved.

In general, when it is necessary to keep the cooling fan rotation speed low from the viewpoint of fan noise, the engine rotation speed is low and the heat load of the internal combustion engine is low, and there is little risk of overheating of the internal combustion engine. Even if the speed is kept low from the perspective of fan noise, it is extremely unlikely that the internal combustion engine will overheat, but for greater safety, the cooling water temperature will be overheated by the internal combustion engine. The cooling fan rotation speed may be rotated at a high speed in accordance with the cooling water temperature, overcoming the fan noise problem at a high temperature such that there is a risk of causing the above.

Example Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows one embodiment of a hydraulically driven cooling fan device having a cooling fan rotation speed control device according to the present invention. In FIG. 1, 10 is a radiator 12 for cooling the engine.
1 shows a cooling fan for supplying cooling air to the cooling fan 10. The cooling fan 10 is rotationally driven by a hydraulic motor 16 such as a hydraulic motor.

The hydraulic motor 16 is configured to increase the rotational speed in response to an increase in the flow rate of a working liquid such as oil supplied thereto, and the working liquid inlet 18 is connected to the flow control valve 22 by a conduit 20, and The working liquid outlet 24 is connected by a conduit 26 to a working liquid reserve tank 28.

The flow control valve 22 is connected to the pump 30. Pump 30
Sucks the working liquid in the reserve tank 28 through the conduit 32,
This is pressure-fed to the flow control valve 22.

The flow control valve 22 is an electromagnetically actuated flow control valve. The flow rate of the working fluid supplied to the hydraulic motor 16 according to the duty ratio of the pulse signal given to the electromagnetic actuating section and the relief passage
The flow rate of returning the working liquid to 23 is controlled to increase or decrease in a mutually opposing relationship. In this embodiment, the flow control valve 22 increases the flow rate of the working liquid supplied to the hydraulic motor 16 in accordance with an increase in the duty ratio of the pulse signal supplied to the electromagnetic operation section, and sends the flow to the relief passage 23. Is reduced.

The duty ratio of the pulse signal applied to the flow rate control valve 22 is controlled by the electric control device 40.

The control device 40 receives information on the temperature of the cooling water of the internal combustion engine from the water temperature sensor 42, information on the rotation speed of the indoor blower motor for indoor air conditioning from the indoor blower motor rotation speed detection means 44, and an intake air amount sensor. The information about the intake air amount of the internal combustion engine is given from 46, and the information about the vehicle speed is given from the vehicle speed sensor 48, and as shown in FIG. 2, the cooling water temperature is determined according to the cooling water temperature. Fan rotation speed determination means 50, basic fan rotation speed upper limit value determination means 52 for determining a predetermined basic fan rotation speed upper limit value, indoor blower for indoor blower for determining the fan rotation speed upper limit value according to the blower motor rotation speed Blower motor rotation speed corresponding fan rotation speed upper limit value determining means 54, and intake air amount corresponding fan rotation speed upper limit value determining means for determining the fan rotation speed upper limit value according to the intake air amount 56, a vehicle speed corresponding fan rotation speed upper limit value determining means 58 for determining a fan rotation speed upper limit value according to the vehicle speed, and a final fan rotation according to the fan rotation speed or the fan rotation speed upper limit value determined by each of the determining means. It has a final fan speed determining means 60 for determining the number, and the final fan speed determining means 60 outputs a pulse signal having a duty ratio according to the final fan speed to the flow control valve 22. There is.

As shown in FIG. 3, the cooling water temperature-corresponding fan rotation speed determining means 50 determines to increase the control target fan rotation speed Ft according to the increase in the cooling water temperature Tw detected by the water temperature sensor 42. Then, this is output to the final fan rotation speed determination means 60.

The basic fan rotation speed upper limit value determining means 52 outputs a predetermined constant basic fan rotation speed upper limit value Ff for ensuring the minimum rotation speed of the cooling fan 10 to the final fan rotation speed determining means 60. There is.

As shown in FIG. 4, the indoor blower blower motor rotation speed-corresponding fan rotation speed upper limit value determining means 54 increases the indoor blower blower motor rotation speed Nb detected by the indoor blower blower motor rotation speed determining means 44. Accordingly, the fan rotation speed upper limit value Fb is determined to be increased, and this is output to the final fan rotation speed determination means 60. This fan rotation speed upper limit Fb is determined according to the noise level caused by the rotation of the indoor blower motor.

The intake air amount corresponding fan rotation speed upper limit value determining means 56 increases the fan rotation speed upper limit value Fq in accordance with the increase of the intake air amount Q detected by the intake air amount sensor 46, as shown in FIG. It is determined so as to output to the final fan rotation speed determination means 60. The fan rotation speed upper limit value Fq is determined according to the engine rotation noise level corresponding to the intake air amount Q.

As shown in FIG. 6, the vehicle speed-corresponding fan rotation speed upper limit value determining means 58 determines to increase the fan rotation speed upper limit value Fv in response to an increase in the vehicle speed V detected by the vehicle speed sensor 48. Is output to the final fan rotation speed determination means 60. The fan speed upper limit value Fv is determined according to the vehicle running noise level corresponding to the vehicle speed.

The final fan rotation speed determination means 60 adds up the fan rotation speed upper limit values Ff, Fb, Fq, and Fv determined by the fan rotation speed upper limit value determination means 52, 54, 56, and 58 as described above to obtain the final value. The fan rotation speed upper limit value Fmax is obtained, and the final fan rotation speed upper limit value Fmax and the cooling water temperature corresponding fan rotation speed determination means
The fan speed Ft determined by 50 is compared, and Ft <Fm
When it is ax, the fan rotation speed Ft is changed to the final fan rotation speed Fn
On the other hand, when Ft <Fmax is not satisfied, the final fan rotation speed upper limit value Fmax is set as the final fan rotation speed Fn, and a pulse signal having a duty ratio corresponding to the final fan rotation speed Fn is output to the flow control valve 22. Has become.

As a result, the fan rotation speed control is performed according to the flowchart shown in FIG. 7, and the cooling fan 10 is rotationally driven at the final fan rotation speed Fn.

Even if one of the fan rotation speed upper limit values is, for example, the vehicle speed-corresponding fan rotation speed upper limit value Fv is kept at a predetermined value at a low vehicle speed as shown by a broken line in FIG. The fan rotation speed upper limit value Ff may be omitted.

When the cooling water temperature Tw is at a predetermined high temperature Twset such that overheating may occur, for example, when it is 100 ° C or higher, the cooling fan 10 is rotated at high speed even if the fan noise problem is sacrificed to avoid overheating of the internal combustion engine When it is necessary to adjust the cooling water temperature Tw to a predetermined value as shown in FIG.
When it is equal to or more than Twset, the final fan rotation speed Fn may be the fan rotation speed Ft determined by the cooling water temperature corresponding fan rotation speed determination means 50 regardless of the final fan rotation speed upper limit value Fmax. In this case, Tw When> Twset or more, the cooling fan 10 always rotates at the fan rotation speed Ft, and the cooling water is more positively and reliably cooled.

9 and 10 show another embodiment of the rotation speed control device for a cooling fan according to the present invention. The ninth
1 and 2, the parts corresponding to those in FIGS. 1 and 2 are designated by the same reference numerals as those in FIGS. 1 and 2. In such an embodiment, pump 30 is an internal combustion engine.
Internal combustion engine 1 that is drivingly connected to 100 output shafts (crankshafts)
It is designed to be driven directly by the axis output of 00.
The pump 30 may be of a general structure having a relief valve built in, and the discharge pressure characteristic of the pump is shown in FIG. That is, the discharge pressure P of the pump 30 becomes the relief pressure Pr only after the engine speed Ne reaches a predetermined value, and is maintained at the relief pressure Pr even if the engine speed Ne further increases. Until Ne reaches the predetermined value, it increases in proportion to the increase in the engine speed Ne.

The control device 40 uses the water temperature sensor 42 to provide information on the cooling water temperature of the internal combustion engine 100, and the rotation speed sensor 62 to supply the internal combustion engine 100
Information regarding the number of revolutions of the internal combustion engine 100 is given from the throttle switch 64, and information regarding whether or not the throttle valve of the internal combustion engine 100 is in the fully closed position (idle opening position).
As shown in FIG. 10, a cooling water temperature corresponding fan rotation speed determining means 50 for determining the fan rotation speed according to the cooling water temperature.
According to the engine rotation speed corresponding fan rotation speed upper limit value determining means 66 for determining the fan rotation speed upper limit value according to the engine rotation speed, and the fan rotation speed or the fan rotation speed upper limit value determined by each of the determination means. The final fan rotation speed determining means 60 for determining the final fan rotation speed is provided, and the final fan rotation speed determining means 60 outputs a pulse signal having a duty ratio according to the final fan rotation speed to the flow control valve 22. It has become.

The cooling water temperature-corresponding fan rotation speed determining means 50 is, as in the above-described embodiment, a water temperature sensor as shown in FIG.
According to the increase in the cooling water temperature Tw detected by 42, the control target fan rotation speed Ft is determined to be increased, and this is output to the final fan rotation speed determination means 60.

The fan speed upper limit value determination means 66 for the engine speed corresponds to the first
As shown in FIG. 12, as the engine speed Ne detected by the engine speed sensor 62 increases, the fan speed upper limit value Fe
Is determined to increase, and this is the final fan speed determination means.
It is designed to output to 60.

The final fan rotational speed determination means 60 unconditionally sets the control target fan rotational speed Ft corresponding to the cooling water temperature as the final fan rotational speed Fn when the throttle valve of the internal combustion engine 100 is not in the fully closed position, that is, when not in deceleration operation. , In contrast, internal combustion engine
When the 100 throttle valve is in the fully closed position, the control target fan speed Ft is compared with the fan speed upper limit value Fe, and Ft
When Fe is less than Fe, the control target Ft is the final fan rotation speed Fn, while when Ft <Fe, the fan rotation speed upper limit value Fe
Is set as the final fan rotation speed Fn, and a pulse signal having a duty ratio according to the final fan rotation speed Fn is output to the flow control valve 22.

As a result, the fan rotation speed control is performed according to the flowchart shown in FIG. 13, and the cooling fan 10 is rotationally driven at the final fan rotation speed Fn.

By the control as described above, for example, the engine speed Ne is reduced by deceleration from high-speed operation, and the fan speed upper limit value Fe is reduced accordingly, and when this becomes smaller than the control target fan speed Ft at this time, cooling is performed. The fan rotation speed of the fan 10 is promptly reduced to a value according to the fan rotation speed upper limit value Fe. As a result, even if the engine speed Ne is reduced, even if the pump discharge pressure P is kept at the relief pressure Pr, the fan speed is quickly reduced according to the engine speed reduction, and the fan noise is generated during deceleration. It avoids being offensive.

In the above, the present invention has been described in detail with respect to specific embodiments, but the present invention is not limited to these, and various embodiments are possible within the scope of the present invention. It will be obvious to the trader.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of a hydraulic pressure type cooling fan device provided with a rotation speed control device according to the present invention,
FIG. 2 is a block diagram showing an embodiment of a cooling fan rotation speed control device according to the present invention, and FIG. 3 shows a cooling water temperature corresponding fan rotation speed characteristic of the cooling fan rotation speed control device according to the present invention. FIG. 4 is a graph showing a fan rotation speed upper limit characteristic corresponding to an indoor blower blower motor rotation speed of a cooling fan according to the present invention, and FIG. 5 is a fan rotation speed upper limit characteristic corresponding to an intake air amount according to the present invention. Graph,
FIG. 6 is a graph showing the fan speed upper limit value characteristic corresponding to the vehicle speed according to the present invention, FIGS. 7 and 8 are flow charts showing the control procedure of the cooling fan rotation speed control device according to the present invention, and FIG. FIG. 10 is a schematic configuration diagram showing one embodiment of a hydraulically driven cooling fan equipped with a rotation speed control device according to the present invention, and FIG. 10 shows another embodiment of the rotation speed control device for a cooling fan according to the present invention. A block diagram, FIG. 11 is a graph showing the discharge pressure characteristic with respect to the engine speed of the pump in the embodiment in FIGS. 9 and 10, and FIG. 12 is the embodiment shown in FIGS. 9 and 10. FIG. 13 is a graph showing the fan rotation speed upper limit value characteristic corresponding to the engine rotation speed of the cooling fan in the example. FIG. 13 is a control procedure of the cooling fan rotation speed control device according to the present invention shown in FIGS. 9 and 10. It is a flowchart showing. 10… Cooling fan, 12 …… Radiator for engine cooling, 16 ……
Hydraulic motor, 18 …… Operating liquid inlet, 20 …… Conduit, 22 …… Flow control valve, 23 …… Relief passage, 24 …… Operating liquid outlet, 26
…… Conduit, 28 …… Reservoir tank, 30 …… Pump, 32 ……
Conduit, 40 ...... Control device, 42 ...... Water temperature sensor, 44 ...... Indoor blower blower motor rotation speed determination means, 46 ...... Intake air amount sensor, 48 ...... Vehicle speed sensor, 50 ...... Cooling water temperature compatible fan rotation speed Determining means, 52 ... Basic fan rotational speed upper limit value determining means,
54 …… Indoor blower blower motor rotation speed corresponding fan rotation speed upper limit value determining means, 56 …… Intake air amount corresponding fan rotation speed upper limit value determining means, 58 …… Vehicle speed corresponding fan rotation speed upper limit value determining means, 60 …… Final Fan rotation speed determination means, 62 ... Rotation speed sensor, 64 ... Throttle switch, 66 ... Engine rotation speed compatible fan rotation speed upper limit value determination means

Claims (1)

(57) [Claims] 1. A cooling water temperature detecting means for detecting a temperature of cooling water for cooling an engine, and a state of a factor causing noise such as a blower motor speed for indoor blower, an intake air amount, a vehicle speed and an engine speed. Cooling water temperature corresponding fan rotation speed determining means for determining the control target rotation speed so that the cooling fan rotation speed increases in accordance with the increase in the cooling water temperature detected by the cooling water temperature detection means. A fan rotation speed upper limit value determining means for determining a fan rotation speed upper limit value that increases in accordance with an increase in the noise generation factor detected by the noise generation factor state detecting means; and the cooling water temperature corresponding fan. The smaller one of the control target rotation speed determined by the rotation speed determination means and the fan rotation speed upper limit value determined by the noise generation factor corresponding fan rotation speed upper limit value determination means. Final fan rotation speed determining means for determining the cooling fan rotation speed based on the number, and cooling fan rotation speed control means for controlling the rotation speed of the cooling fan based on the fan rotation speed determined by the final fan rotation speed determining means. And a rotation speed control device for a cooling fan of a vehicle internal combustion engine having: