JPS62261613A - Cooling control device for vehicle - Google Patents

Abstract

PURPOSE:To raise precision in control, by setting a by-pass route in parallel with a hydraulic motor which drives a cooling fan, and return-controlling the rotating speed of the cooling fan, through a resistance control means set in said by-pass route, to the desired value which is set according to heat load condition of a regenerator. CONSTITUTION:A working fluid discharged from a hydraulic pump 11, is controlled in its flow by the first flow control valve 13, and after that, fed to a hydraulic motor 14 to drive a cooling fan 15 adapted to blow air toward a radiator 16 and a condenser 17. A flow control valve 21 is set in a by-pass route B by-passing the hydraulic motor 14, and this flow control valve 21 is controlled by an engine control unit 22. Detected values from a rotating speed sensor 23 of the cooling fan 15, a water temperature sensor 24 of the radiator 16, and a pressure sensor 25 of the condenser 17, are input into the engine control unit 22, this control unit 22 calculates the desired rotating speed of the cooling fan 15 according to heat load of a regenerator, and return-control is performed through the flow control valve 21.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cooling system installed in a vehicle such as an automobile equipped with an engine, in particular a hydraulic motor using hydraulic pressure as a driving source for a cooling fan. The present invention relates to a cooling control device for a vehicle that stably controls the rotation of the cooling fan when a cooling fan is used.

[Prior Art] Generally, as a means for cooling engine cooling water, a cooling fan directly connected to the engine supplies cooling air to a heat exchanger such as a radiator through which the cooling water passes. It consists of

In addition, we have taken into account restrictions on installing cooling fans in vehicles and their negative impact on fuel consumption, and have also improved the start-up characteristics of heaters for in-vehicle heating, and considered the impact on exhaust gas purification devices such as manifolds and catalytic converters. In order to improve this, it is also being considered to drive the cooling fan by an electric motor so that the rotational speed of the cooling fan can be controlled.

However, when the cooling fan is driven by an electric motor, the output of the electric motor is limited by the size of the fan, so it is difficult to reduce the rotation speed and increase the torque. In this case, a large amount of power is required, and the power consumption increases. Therefore, vehicles using such electric motors have been used only in small passenger cars.

However, in order to shorten the start-up time of the heater in passenger cars that use FF or diesel engines, it is required to separate the cooling fan from the engine and freely control its rotation even in medium and large vehicles. It looks like this. However, in such medium and large vehicles, the engine generates a large amount of heat, so a large amount of cooling air is required to cool the heat exchanger that supplies the engine's cooling water. Become.

In other words, the electric motor that drives the cooling fan becomes larger, which not only increases power consumption, but also increases the power consumption.
Problems also arise in terms of vehicle mountability.

As means for driving the cooling fan, in addition to the above-mentioned electric motor, a hydraulic pump may be used to generate fluid pressure, as shown in Japanese Patent Publication No. 49-40183, Japanese Utility Model Publication No. 58-136621, etc. It has been considered that the cooling fan be driven by a hydraulic motor connected to the cooling fan. Specifically, a hydraulic pump driven by an engine generates hydraulic pressure, and this hydraulic pressure drives a hydraulic motor to rotate.The rotational speed of this motor is determined by the driving hydraulic pressure supplied to this motor. The setting is controlled, and the driving oil pressure can be controlled depending on the state of thermal load, etc.

However, with this method of driving a cooling fan using hydraulic pressure, there are problems such as changes in the temperature of the fluid used, deterioration of the hydraulic pump and even hydraulic motor, and changes in the discharge volume of the hydraulic pump. Due to fluctuations and the like, it may be difficult to stably set the rotation speed of the cooling fan, and it may be difficult to perform highly accurate cooling control.

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned points, and the cooling fan is driven by a hydraulic motor using hydraulic pressure or the like, and the rotational state of the cooling fan is controlled depending on the situation. A cooling control device for a vehicle that allows variable control to be performed in response to This is what we are trying to provide.

[Means for Solving the Problems] That is, in the cooling control device for a vehicle according to the present invention, fluid pressure generated by a hydraulic pump is supplied to a hydraulic motor, and the hydraulic motor A cooling fan that sends cooling air to a heat exchanger is driven to rotate, and in this case, a bypass passage is formed in parallel with the hydraulic motor, and a flow rate control mechanism is set in this bypass passage. This control mechanism controls the flow rate of liquid flowing into the hydraulic motor, thereby controlling the rotational speed of the motor. The flow rate control mechanism controls the bypass flow rate depending on the situation, and is feedback-controlled by a detection signal of the rotational speed of the cooling fan.

[Function] In the cooling control device for a vehicle as described above, the rotation of the cooling fan is controlled at a rotation speed depending on the situation. The rotation speed of this fan is controlled by a control unit composed of a microcomputer, etc., depending on the heat load state of the heat exchanger, etc., but it also depends on the temperature of the fluid used, etc. Depending on the situation, the fan rotation speed may differ even with the same amount of fluid.

Therefore, the bypass flow rate is controlled by comparing the detection signal of the actual cooling fan rotation speed with the required fan rotation speed according to the above situation, and the cooling fan rotation speed is adjusted to the above required rotation speed. This will ensure stable settings.

[Embodiments of the invention] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration, and in this embodiment, the fluid supplied to the power steering mechanism is also controlled at the same time.

This cooling control device is equipped with a hydraulic pump 11 that is rotatably driven by an engine mounted on a vehicle (not shown in this figure), and this hydraulic pump 11 pumps hydraulic oil from an oil tank 12, It is designed to discharge Qo of hydraulic oil. The hydraulic oil discharged by this hydraulic pump 11 is supplied to the first flow control valve 13,
This control valve 13 outputs a flow W Q l of hydraulic oil. The hydraulic oil from this control valve 13 is supplied via an oil vibrator to a hydraulic motor 14 of, for example, a float type, a vane type, a piston type, etc. in a flow Q Q 2, and drives this motor 14 to rotate. .

A cooling fan 15 is connected to this hydraulic motor 14, and the cooling air generated by this cooling fan 15 is sent to a radiator 16 through which engine cooling water is circulated.
Furthermore, it is supplied to a heat exchanger portion such as a condenser 17 to which a cooling medium of an air conditioner installed in a vehicle is supplied.

The hydraulic pressure and the hydraulic oil that has passed through the motor 14 are supplied to the power steering device 19 via the second flow control valve 18 and returned to the oil tank 12.

Here, the hydraulic motor (4) is provided with first and second bypass passages A and B which are arranged in parallel. A pressure control valve 20 is set in the first bypass passage A, and when the power steering device 19 operates, hydraulic oil is branched preferentially so that the power steering device 19 operates normally. Further, the second bypass passage B is provided with a third flow rate control valve 21 as bypass passage resistance control means. This control valve 21 has 1 yt
The hydraulic oil of E HQ 4 is allowed to flow, and the hydraulic pressure acting on the hydraulic motor 14 is controlled in accordance with the flow rate of the hydraulic oil flowing to this control valve 21, and the rotation speed of this motor 14, That is, the rotational speed of the cooling fan 15 is variably controlled.

The first and third flow rate control valves 13 and 21 have their passage flow rates controlled by excitation currents supplied to solenoids 131 and 211, respectively. It is controlled by an electronic engine control unit 22 formed by a computer or the like. The second flow rate control valve 18 is controlled to set the output flow rate to Q6.

The cooling fan 15 is provided with a rotation sensor 23 that detects the rotation speed of the fan 15.
A rotation speed detection signal from this sensor 23 is supplied to the control unit 22. Further, the radiator 16 is provided with a cooling water temperature sensor 24, and the condenser 17 is further provided with a pressure sensor 25, which detects the high-pressure side pressure of the cooling medium and is constituted by, for example, a high-pressure switch. The detection signals from these sensors 24 and 25 are supplied to the control unit 24 as a situation detection signal. This control unit 22 is further supplied with a signal from an air conditioner switch 26.

The engine control unit 22 is used to control the engine (not shown in this figure), and is used to detect signals related to engine operating conditions such as intake air amount, engine speed, air-fuel ratio, etc. Based on this, the fuel injection amount, ignition timing, etc. are calculated, and fuel injection control, ignition control, etc. are executed.The control unit 22 also controls the cooling system.

FIG. 2 is for explaining the configuration of the above engine control unit 22, especially the part that executes cooling control, and includes a water temperature sensor 24, an air conditioner pressure sensor 25 consisting of a high pressure switch, and an air conditioner switch 26.
Detection signals from the heat load level selection circuit 31 are supplied to the heat load level selection circuit 31.

Specifically, the water temperature sensor 24 generates a signal corresponding to the resistance value of a detection element whose resistance value changes in accordance with the cooling water temperature, and the pressure sensor 25 generates a signal that indicates that the pressure of the cooling medium is at a high level when the pressure is high. When this is not the case, a low level signal is generated, and the air conditioner switch 2B generates a signal that changes to high level and low level corresponding to on and off, respectively, and these sensors 25.2B
A detection signal is generated from the In the heat load level selection circuit 31, each sensor 2
The heat load level is determined based on the detection signals from 4 to 2B, and an output voltage el corresponding to the determination result is generated.

Further, the rotation speed sensor 23 generates a frequency signal corresponding to the rotation speed of the cooling fan 15, and this frequency signal is converted by the frequency-voltage conversion circuit 32 into a voltage signal e2 corresponding to the rotation speed. , this voltage signal e2 is supplied to the differential amplifier 33 to determine the thermal load judgment output voltage e1.
Compare with. In this differential amplifier 33, "et-e2J
differential amplification is performed, and the output signal is sent to a comparator 34.
supply to.

This comparator 34 is supplied with a triangular wave signal from a triangular wave oscillation circuit 35, and slices the triangular wave signal using the output signal from the differential amplifier 33 as a threshold level, and adjusts the level of the output signal from the differential amplifier 33 to the level of the output signal from the differential amplifier 33. A pulsed rectangular wave signal with a correspondingly set duty ratio is output. Then, this rectangular wave signal whose duty is set is appropriately amplified and supplied to the solenoid 211 of the third flow control valve 21 as an exciting current.

The output signal e1 from the thermal load level selection circuit 31 is
Further, the voltage is supplied to a comparator 36 and compared with a reference voltage e3 set by a resistance circuit.

And from this comparator 3G, “el>e3J
If so, a high level output signal is generated and rel > e3
J, a low level output signal is generated, and the output signal from the comparator 36 is supplied to the solenoid 131 of the first flow control valve 13 as an exciting current. That is, the first control valve 13 controls the flow rate to be switched in two stages depending on the state of the heat load.

Here, in the heat load level selection circuit 31, for example, when the water temperature is 100° C. or higher or the cooling medium pressure is 1.5 Mp or higher, the first flow control valve 13
It generates a "large" signal that excites the solenoid 211 so that a large flow rate is set, and when the water temperature is low, the flow rate is set to a low value, including the relationship with the air conditioner switch. Set the value to "Small" or "
It generates an extremely small signal.

The amount of oil discharged from the hydraulic pump 11 increases as the engine speed increases, so the amount of oil output from the first flow control valve 13 also increases as shown in FIG. 3(A). It increases in accordance with the engine speed Ne. When this output flow ff1Q1 reaches a, part of the hydraulic oil is drained into the oil tank, and the flow ff1Q1 is maintained at a.

In this case, when the excitation current is supplied to the solenoid 131, the variable throttle area inside the control valve 13 is controlled in two stages, and the flow rate Ql increases as shown in b in Fig. 3(A). It can be switched to the side. That is, the output flow rate of the first flow rate control valve 13 is changed depending on the heat radiation load state of the cooling system, and in normal operation or in a state where the heat radiation load is small, the output flow rate of the first flow rate control valve 13 is changed.
mQ1 is set to a small flow ff1a, and in a state where the heat radiation load is large, the flow WQI is switched and controlled to a large flow rate.

Here, the determination of "large", "small", and "minimum" by the heat load level selection circuit 31 is based on the relationship shown in FIG. is set to .

The third flow rate control valve 21, which connects the upstream side and the downstream side of the hydraulic motor 14 to form a bypass passage B, has a flow rate variably controlled in response to the control current 1. The differential pressure ΔPs is variably controlled as shown by the solid line in FIG. 3(B). That is, due to this differential pressure ΔPs, the differential pressure rP between the input and output ends of the hydraulic motor 14
1-P2J is controlled, and the rotation speed of the hydraulic motor 14, that is, the rotation speed of the cooling fan 15, is set in accordance with this differential pressure. Specifically, when the differential pressure is large, the cooling fan 15 is rotated at a high rotation speed, and when the differential pressure is small, the fan 15 is rotated at a low rotation speed.

Here, the differential pressure ΔPs generated by the flow rate control valve 21 changes as shown by the solid line in FIG. 3(B) depending on the control current i supplied from the control unit 22 as described above. However, this differential pressure ΔPs is affected by the temperature of the hydraulic oil, and for example, when the oil temperature is low, it is shown by the solid line T1, and when the oil temperature is high, it is shown by the solid line T2.
This is as shown in the figure below.

The switching valve 20 set in the first bypass passage A is controlled using the fluid pressure P2 on the upstream side of the second fluid control valve 18 as a pilot pressure, and the flow f:LQ3 of this bypass passage A is It is designed to be controlled by switching. This switching valve 20 is constituted by, for example, a spool valve, and a taper is formed on the land of the spool so that the flow rate Q3 does not suddenly change during the switching operation, that is, this flow QQ3 is continuously changed. has been done.

Then, as shown in FIG. 3(C), when the switching valve 20 reaches a state where the pilot pressure P2 exceeds a predetermined pressure,
The flow rate Q3 of this bypass passage A is continuously switched and controlled from zero to the flow rate ff1Ql set by the first flow rate control valve 13 in accordance with the pressure. By performing such an operation, when a load is applied to the power steering device 19 and a large steering force is required, the pilot pressure P2 increases.
The switching valve 20 increases a Q Q 3 of the bypass passage A, and hydraulic oil is supplied to the power steering device 19 preferentially.

In this case, since the flows Q and Q3 are raised continuously, the steering force does not change suddenly when the switching valve 20 is switched, and the hydraulic fluid is transferred from the hydraulic motor 14 to the power source. The steering device 19 can be switched smoothly.

The second flow rate control valve 18 controls the iX
This control valve 18 controls E=QB, and drains excess oil into an oil tank so that the hydraulic oil supplied to the power steering device 10 does not exceed a predetermined value =a.

FIG. 4(B) is for explaining the operating state of the above embodiment device based on the heat dissipation load determination result shown in FIG. 4(A), and corresponds to each of the four patterns 1 to It shows. Here, Q1 to Q6 are the flow rates of the corresponding parts shown in Fig. 1, and a and b are the flow rates of the corresponding parts shown in Fig. 3 (A).
These correspond to the flow rates a and b shown in FIG.

Wow, the downstream flow port Q1 of the first flow control valve 13
is the solenoid 1 controlled by the control unit 26
31, for example, in the off state where no excitation current is supplied, the normal flow a is set, and in the on state where the excitation current is supplied, the large flow ff1b (>a) is set. Here, the flow Qa is set to the minimum flow rate required by the power steering device 19. The flow Q Q 4 flowing into the bypass passage B is a third flow which sets the differential pressure ΔPs by the excitation current supplied to the solenoid 211.
Q4 is proportionally controlled within the range of a-OJ by the excitation current.The flow mQ2 flowing to the hydraulic motor 14 is
The flow rates are controlled by the flow rates Q3 and 4 of the first and second bypass passages A and B.

IN, = 05 and Q6 indicate the flow rates on the upstream side and downstream side of the second flow control valve 18, respectively. Here,
FIG. 4(D) shows the relationship between the dry rudder torque and the output torque of the power steering device 19 when there is no hydraulic oil and when the flow rates are a and b.

In (B) of FIG. 4 above, pattern E shows the case where steering is being executed, and in this case, the switching valve 20 is kept open regardless of the heat load state.
The hydraulic oil discharged from the hydraulic pump 11 is supplied to the hydraulic motor 1.
The steering force is set normally by bypassing the fourth part and supplying it to the power steering device 19.

In patterns ■～■ without steering, radiator 1
The engine control unit 22 comes to control the flow rate control valves 13 and 21 in response to the heat load state of the G and the condenser 17. Specifically, solenoids 131 and 211 of flow control valves 13 and 21 are controlled as shown in FIG. 4(C).

As shown in FIG. 3(B), even if the control current i supplied to the solenoid 211 of the flow control valve 21 is the same depending on the temperature state of the hydraulic oil, the differential pressure Δ set by the upper control valve 21 is
Ps is different. As shown in this figure, when the differential pressure ΔPs becomes different, even if the control current i is the same, the rotational speed Nf' of the cooling fan 15 changes, and the temperature of the hydraulic oil becomes high. In this state, the rotational speed of the cooling fan 15 is controlled to be low even with the same control current i.

However, in the above device, the rotation speed of the cooling fan 15 is detected by the sensor 23, the voltage signal e2 corresponding to this rotation speed is supplied to the differential amplifier 33, and 82 is subtracted from the voltage signal el. There is. That is, the flow rate of the third flow rate control valve 21 is feedback-controlled by the rotation speed of the cooling fan, and the rotation speed of the cooling fan 15 is accurately controlled to a state corresponding to the heat load state. It becomes like this. Furthermore, the engine rotation speed,
The rotation of the cooling fan 15 is controlled at an appropriate speed without being affected by deterioration of the pump, motor, etc.

FIG. 5 shows an example of a hydraulic motor 14 that rotationally drives a cooling fan 15 used in the above-mentioned cooling control device. As this motor 14, a commonly known motor may be used as appropriate. Ru. This example is an external gear motor 141
In this figure, iron gears 143 and 144 are housed in a housing 142 so as to mesh with each other. The output shaft of the gear 143 is connected to the rotating shaft of the cooling fan 15. Hydraulic oil is force-fed into the housing 142 from the inlet 145 and discharged from the outlet 14B, and the gears 143 and 144 are rotated in response to the flow of the hydraulic oil, causing the cooling fan 15 to rotate. becomes rotationally driven.

Inside the housing 142, a rod-shaped detection core 147 made of a magnetic material is exposed and set close to the outer periphery of the gear 144. An insulator made of aluminum is set around this core 147. The insulator isolates the lines of magnetic force between the core 147 and the housing 142. A permanent magnet 14111 is integrally set in the core 147, and a detection coil 149 is attached to this permanent magnet 148.
is now wrapped.

That is, when hydraulic oil is supplied and the gears 143 and 144 rotate, and the cooling fan 145 is driven to rotate, a large number of teeth of the gear 144 come to pass close to the detection core 147. In response to the close passage of teeth,
A pulsed detection signal is now generated from the detection coil 149. That is, the generation period of this pulse-like detection signal corresponds to the rotational speed of the cooling fan 15, and therefore the output voltage signal e2 from the frequency-voltage conversion circuit 32 corresponds to the rotational speed of the cooling fan 15. It is something that comes to be expressed.

Various other motors can be used as the hydraulic motor 14, and for example, an internal gear motor can also be used as appropriate. In the case of this internal gear motor as well, if a detection core as shown in Fig. 5 is set close to the passing position of the gear teeth set in the housing, a cycle corresponding to the same rotational speed as described above can be obtained. A pulse signal is generated.

In the above embodiment, the flow of hydraulic oil generated by the hydraulic pump 11 is used as a rotational drive source for the cooling fan 15, and is also used for the power steering device. Hydraulic pump 1 as shown in
The hydraulic pressure generated in step 1 may be used only for the hydraulic motor 14 that drives the cooling fan 15. Therefore, in this case, the first bypass passage A for ensuring oil pressure in the power steering device is not required. In this figure, the same parts as in FIG. 1 are designated by the same reference numerals, and the explanation thereof will be omitted.

Further, in the above embodiment, the amount of hydraulic fluid discharged from the hydraulic pump 11 is controlled by the first flow control valve 13. However, if a hydraulic pump ill whose discharge amount can be controlled as shown in FIG. 7 is used, there is no particular need to set the flow rate control valve 13. In this case, the engine control unit 22 controls the solenoid lla that variably controls the discharge port of the hydraulic motor 111.
may be controlled in the same way as the solenoid 131.

In the above embodiment, the control system using hydraulic fluid was explained, but other fluids may be used as the working fluid, and in this case, a control system that uses hydraulic fluid may be used. A hydraulic pump, a hydraulic motor, etc., are used.

[Effects of the Invention] As described above, according to the cooling control device for a vehicle according to the present invention, the rotation of the cooling fan is controlled at a speed corresponding to the heat load state of the cooling device, and the cooling function is improved. is set in accordance with the operating state of the engine, etc., so that, for example, warm-up operation etc. can be executed effectively. Furthermore, even if there are factors that cause the rotational speed of the cooling fan to fluctuate depending on conditions such as temperature, the rotational speed of the cooling fan can be controlled with high precision in a state that matches the heat load condition. This allows the cooling system to be stably controlled in accordance with the vehicle and engine conditions.

[Brief explanation of drawings]

FIG. 1 is a block diagram explaining a cooling control device for a vehicle according to an embodiment of the present invention, FIG. 2 is a diagram explaining the structure of a control unit used in the above embodiment, and FIG. )～(
D) is an operation characteristic diagram for explaining the operation state of the above embodiment, FIG. A cross-sectional configuration diagram showing a specific example of a hydraulic motor used in the embodiment, and FIGS. 6 and 7 are configuration diagrams illustrating other embodiments of the present invention, respectively. 11...Hydraulic pump, 13.18.21...Flow control valve, I4...Hydraulic motor, I5...Cooling fan,
I6...Radiator (heat exchanger), 17...Condenser (air conditioner), 19...Power steering device,
20...Switching valve, 22...Engine control unit,
23... Rotation sensor, 24... Water temperature sensor, 25...
・Pressure sensor, 25...Air conditioner switch. Applicant's agent Patent attorney Takehiko Suzu (A)
(B) Figure 3

Claims (1)

[Scope of Claims] A hydraulic pump that pumps fluid to generate fluid pressure; a cooling fan that supplies airflow to a heat exchanger to which a cooling medium is supplied; A hydraulic motor rotatably driven by fluid supplied by a hydraulic pump, and a bypass passage provided in parallel with the hydraulic motor to control the amount of fluid supplied to the hydraulic motor. bypass passage resistance control means for controlling the flow rate control means in accordance with the thermal load state of the heat exchanger to set the rotational speed of the hydraulic motor;
a control means, a means for detecting the rotation speed of the cooling fan, and a comparison between the rotation speed detected by the detection means and the motor rotation speed set by the first control means, A cooling control device for a vehicle, comprising: second control means that performs feedback control so that the rotation is performed at a speed set by the first control means.