JP2549448Y2 - Rotary speed control device for cooling fan for hydraulically driven internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a rotation speed control device for a cooling fan of an internal combustion engine used for a vehicle such as an automobile, and more particularly to a hydraulically driven variable speed cooling fan. According to the present invention.

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 a radiator for cooling the engine is driven by a hydraulic motor such as a hydraulic motor, and its rotation speed is controlled by a cooling water temperature or the like. It is already known that the control is performed according to the following.
It is shown in each gazette of the issue.

In the cooling fan rotation speed control device as described above, the pump for supplying the working liquid to the hydraulic motor is drivingly connected to the output shaft of the internal combustion engine and is directly rotated by the internal combustion engine. Therefore, when the internal combustion engine is operating at a high speed, the pump is also rotated at a high speed, and the internal pressure of the pump increases accordingly. As described above, when the pump rotates at a high pressure at a high speed, the durability of the pump is reduced and the pump noise is increased as compared with the case where the pump rotates at the same pressure at the bottom.

From this, an upper limit value of the fan control amount is set for the engine speed, and when the engine speed is high, the relief amount of the working liquid is increased so as to reduce the rotation speed of the cooling fan as compared with when the engine speed is low, thereby increasing the pump. It has been considered to suppress the rise of the internal pressure to improve the durability of the pump and reduce the pump noise. This is realized by Japanese Patent Application No. 62-58002 and Japanese Patent Application No. 62-58002 by the same applicant as the present applicant. It has already been proposed in -329037.

[Problem to be Solved by the Invention] In a vehicle internal combustion engine such as an automobile, a pump for driving a hydraulic motor as described above is used together with auxiliary devices such as an alternator and an air conditioning compressor by a serpentine belt or the like. Are collectively drivingly connected to the output shaft.
The torque required to drive these auxiliary devices is generally the lowest when the engine is rotating at medium speed, and increases when the engine speed increases or decreases. When the engine is running at a low speed, the instantaneous torque further increases because the torque unevenness is large. Therefore, when the hydraulic motor driving pump is similarly driven in addition to the above-described auxiliary device during the idling operation in which the driving torque required for driving the auxiliary device is large and in the engine low speed rotation region in the vicinity thereof, The tensile load acting on the driven transmission belt further increases, and the durability of the transmission belt is greatly reduced in combination with the increase in slip between the belt and the pulley due to uneven torque.

The present invention reduces the rotation speed of the cooling fan to a lower rotation speed than the engine rotation speed without affecting the cooling performance of the engine during idle operation and in the vicinity of the low engine speed region. Focusing on the fact that it is possible, we propose to control the drive speed of the hydraulic motor for driving the cooling fan to be further reduced in comparison with the speed of the internal combustion engine in such a low engine speed range. Things.

In this case, the idle operation or the low-speed rotation state of the engine in the vicinity thereof includes the case where the engine is changed from the middle or high-speed operation state to the low-speed operation state in the vicinity of the idle operation or the state where the engine is started from the low temperature state while the engine is started from the low temperature state. There is some difference in the rotation speed required for the cooling fan in the case where the rotation speed of the cooling fan drive hydraulic motor is reduced in comparison with the engine rotation speed in such a low rotation region. Must be defined on the premise that the engine has reached the low-speed operation state from the medium or high-speed operation state, that is, the state in which the engine cooling water temperature has reached a certain predetermined cooling water set temperature. However, in a state where the engine is started from the cold temperature state and remains in the low-speed rotation state as it is, and the engine cooling water temperature has not yet reached the predetermined set temperature, the rotation speed of the cooling fan driving hydraulic motor is set to the above-described speed. The rotation speed may be set to be lower than the rotation speed set in the manner described above, whereby the durability of the power transmission belt can be further improved.

The present invention further focuses on this point, and aims to further improve the durability of the power transmission belt.

According to the present invention, the working liquid is supplied to a hydraulic motor from a pump that is drivingly connected to an output shaft of an internal combustion engine and is driven by the internal combustion engine. Cooling for detecting the temperature of cooling water for engine cooling in a rotation speed control device of a cooling fan for a hydraulic pressure driven internal combustion engine, the rotation speed of which is controlled in accordance with the flow rate of the working liquid supplied to the hydraulic motor. Water temperature detecting means, engine speed detecting means for detecting the engine speed of the internal combustion engine, and a fan control amount for determining the cooling fan speed to a predetermined low speed when the cooling water temperature is equal to or lower than a predetermined value. Means for determining a cooling water temperature-responsive fan control amount, wherein the cooling fan rotation speed relative to the engine speed is higher than when the engine speed is in the middle speed range when the engine speed is in idling operation and in the low speed range in the vicinity thereof according to the engine speed. Relative numbers A fan control amount determining means for determining a fan control amount to reduce the fan control amount, and a fan control amount determined by the cooling water temperature corresponding fan control amount determining means when the engine is in idling operation and in a low-speed region near the idle operation. And final fan control amount determining means for determining the rotation speed of the cooling fan based on the fan control amount of the smaller fan speed among the fan control amounts determined by the engine speed corresponding fan control amount determining means. A flow control means for controlling the working fluid supplied to the hydraulic motor based on the fan control amount determined by the final fan control amount determination means when the engine is in idling operation and a low-speed region near the idle operation. Achieved by a speed controller.

According to the configuration as described above, when the engine speed is low, the upper limit value of the rotation speed of the cooling fan is set low, so that the driving torque of the auxiliary device is large in the engine low speed range. In this case, the load acting on the power transmission belt for driving the pump and the auxiliary equipment is reduced, and the durability of the power transmission belt is prevented from being reduced.

Further, an operation in which the engine cooling water temperature is equal to or lower than a predetermined value and a cooling fan rotation speed that is lower than the cooling fan rotation speed determined by the engine rotation speed in the engine low rotation speed range is allowed from the viewpoint of the engine cooling water temperature. In this state, the durability of the transmission belt is further improved by driving the cooling fan at a lower rotation speed based on the engine cooling water temperature.

[Embodiment] The present invention will be described in detail below 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 the drawing, reference numeral 10 denotes a cooling fan that supplies cooling air to the engine cooling radiator 12, and the cooling fan 10
Are driven to rotate by a hydraulic motor 16.

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
The output shaft 38 of the internal combustion engine 36 is controlled by the belt type transmission 34.
And is rotationally driven by the internal combustion engine 36 in a direct-acting manner. Pump 30 is reserved tank 28
The working fluid is sucked up through the conduit 32 and is supplied to the flow control valve 22.
To be pumped to

Although not shown in the drawing, the belt-type transmission device 34 is collectively driven and connected to the output shaft 38 together with auxiliary devices such as an alternator and an air-conditioning compressor by a serpentine belt or the like according to a usual method.

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 supplied to the flow control valve 22 is controlled by an electric control device 40.

The control device 40 receives information on the temperature of the cooling water of the internal combustion engine 36 from the water temperature sensor 42 and information on the engine speed of the internal combustion engine 36 from the engine speed sensor 44, as shown in FIG. A cooling water temperature-responsive fan control amount determining means 50 for determining a fan control amount, that is, a duty ratio, so that the cooling fan rotation speed increases in accordance with an increase in the cooling water temperature.
The fan control amount determining means 52 for determining the fan control amount to reduce the cooling fan rotation speed in accordance with the increase in the engine speed, and the cooling water temperature corresponding fan control amount determining means 50 Of the fan control amount and the fan control amount determined by the engine speed corresponding fan control amount determination means 52, the one with the lower cooling fan rotation speed, in other words, the one with the larger relief flow rate of the working liquid by the flow control valve 22 Final fan control amount determining means 54 for determining the fan control amount of the final fan control amount as the final fan control amount.The final fan control amount determining means 54 sends a pulse signal of a duty ratio based on the final fan control amount to the flow control valve 22. Output.

As shown in FIG. 3, the cooling water temperature-responsive fan control amount determining means 50 determines to increase the fan control amount Dt in accordance with an increase in the cooling water temperature Tw.

As shown in FIG. 4, the engine speed corresponding fan control amount determining means 52 determines that the engine speed Ne is a first predetermined value Nese.
t ₁ , for example, when the engine speed is equal to or lower than the low engine speed, the fan control amount Dn is set to the minimum value Dnmin, and the engine speed N
When e is a value between the _first predetermined value Neset ₁ and the second predetermined value Neset ₂ higher than this, the fan control amount Dn is set to the maximum value Dnmax, and the engine speed Ne becomes the second predetermined value. Neset ₂
In the above case, the fan control amount Dn is determined to be reduced according to the increase in the engine speed Ne.
Note that the minimum value Dnmin is set to a value that guarantees that the required fan air volume is obtained in the low engine speed range.

FIG. 5 is a flowchart showing an example of an operation procedure of the cooling fan rotation speed control device according to the present invention. The control routine of the flowchart shown in FIG. 5 is repeatedly executed as a time interrupt or the like. In the first step 10, the cooling water temperature Tw detected by the water temperature sensor 42 is used as shown in FIG. The fan control amount Dt is determined according to the characteristics. After step 10, the process proceeds to step 20.

In step 20, the fan control amount Dn is determined based on the engine speed Ne detected by the engine speed sensor 44 in accordance with the characteristics shown in FIG. After step 20, the process proceeds to step 30.

In step 30, it is determined whether the fan control amount Dt depending on the cooling water temperature is smaller than the fan control amount Dn depending on the engine speed Ne. When Dn> Dt, the process proceeds to step 40; otherwise, the process proceeds to step 50.

In step 40, the cooling water temperature dependent fan control amount
Dt is set as the final fan control amount D.

In step 50, the fan control amount depending on the engine speed is
Dn is set as the final fan control amount D.

After step 40 and step 50, proceed to step 60,
In step 60, a pulse signal having a duty ratio based on the final fan control amount D is output to the flow control valve 22. As a result, the flow control valve 22 controls the flow rate of the working liquid supplied to the hydraulic motor 16 and the flow rate of the working liquid to the relief passage 25 to increase or decrease in a mutually contradictory relationship in accordance with the duty ratio. Thereby, the cooling fan 10 is driven to rotate at a rotation speed according to the duty ratio.

In the above, the present invention has been described in detail with respect to a specific embodiment, but the present invention is not limited to this.
It will be apparent to those skilled in the art that various embodiments are possible within the scope of the invention.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of a hydraulically driven cooling fan device having a rotation speed control device according to the present invention,
FIG. 2 is a block diagram showing one embodiment of a cooling fan rotation speed control device according to the present invention, and FIGS. 3 and 4 are graphs showing fan control characteristics of the cooling fan rotation speed control device according to the present invention. FIG. 5 is a flowchart showing the control procedure of the cooling fan rotation speed control device according to the present invention. 10… Cooling fan, 12 …… Radiator for engine cooling, 16 ……
Hydraulic motor, 18… Working fluid inlet, 20… Conduit, 22… Flow control valve, 24… Working fluid outlet, 26 …… Conduit, 28… Reserve tank, 30… Pump, 32… Conduit , 34 ... belt type transmission device, 36 ... internal combustion engine, 40 ... control device, 42 ... water temperature sensor, 44 ... engine speed sensor, 50 ... cooling water temperature corresponding fan control amount determination means, 52 ... ... Fan determining means corresponding to rotation speed, 54 ... Final fan control amount determining means

Claims (1)

(57) [Scope of request for utility model registration] A hydraulic fluid is supplied to a hydraulic motor from a pump that is drivingly connected to an output shaft of the internal combustion engine and is driven by the internal combustion engine, and a rotation speed is set according to a flow rate of the hydraulic fluid supplied to the hydraulic motor. Water temperature detection means for detecting the temperature of cooling water for cooling the engine, and an engine for detecting the engine speed of the internal combustion engine Rotation speed detection means, cooling water temperature corresponding fan control amount determination means for determining a fan control amount to set the cooling fan rotation speed to a predetermined low rotation speed when the cooling water temperature is equal to or lower than a predetermined value, When the engine speed is in idling operation and in the low speed range near the engine speed, the engine speed is determined so as to lower the cooling fan speed relative to the engine speed compared to when the engine speed is in the middle speed range. Supported files A control amount determining means, a fan control amount determined by the cooling water temperature corresponding fan control amount determining means and an engine speed corresponding fan control amount determining means when the engine is in an idling operation and a low speed region near the idle operation. Final fan control amount determining means for determining the rotation speed of the cooling fan based on the fan control amount of the cooling fan whose rotation speed becomes smaller among the fan control amounts, and when the engine is in idling operation and in a low speed region near the idle operation. A flow rate control unit for controlling a working liquid supplied to the hydraulic motor based on the fan control amount determined by the final fan control amount determination unit.