JPS61250331A - Cooling system vehicles - Google Patents

Abstract

PURPOSE:To make a cooling fan and a steering mechanism both drivable with one hydraulic pump as well as to aim at simplification in a cooling system, by constituting it so as to make a supply fluid selectively feedable to a hydraulic motor for the cooling fan or the steering mechanism by means of a flow selecting device. CONSTITUTION:When steering operation takes place, a selector valve 26 of a second bypass passage B is opened by an ECU 33, and discharge oil out of a hydraulic pump 15 is preferentially fed to a power steering 16, whereby steering assist force is secured by hydraulic pressure. On the other hand, when the steering operation is not carried out, a discharge flow regulating valve 21 and a solenoid selector valve 23 of a first bypass passage A both are controlled on the basis of each radiation load out of a radiator 20 and a condenser 19. That is to say, when the radiation load is medium small and minimal, a flow rate Q1 is set down to a normal flow rate, and the solenoid selector valve 23 is controlled to valve positions a, b and c according to the radiation load, while when the radiation load is large, the flow rate Q is set to a large flow rate, and the solenoid valve 23 is situated in the valve position (a) whereby rotation of a cooling fan 17 is controlled by a hydraulic motor 17.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a cooling system for a vehicle such as an automobile equipped with an internal combustion engine. The present invention relates to a cooling fan driving method and control method for a cooling system.

(Prior Art) Conventionally, as a cooling system for a vehicle, one in which cooling air is guided to a heat exchanger by a cooling fan that is directly connected to and driven by an engine has been used.

On the other hand, we also aim to improve the problems associated with installing cooling fans in vehicles, their negative impact on fuel consumption, the startup characteristics of heaters, and the impact on exhaust gas purification devices such as manifolds and catalytic converters.

In recent years, a system has been put into practical use that uses an electric motor to drive a cooling fan and controls the operation of an electric lantern based on detection signals of cooling water temperature and refrigerant pressure. This system is limited by the electric motor's physique, that is, the output is small for its physique, and it is difficult to reduce the rotation speed and increase the torque. Further, because the current consumption tends to be large (especially at startup), the use in passenger cars has been limited to small cars. However, due to the shift to front-wheel drive (FF) vehicles and the shortening of the start-up time of the heater in diesel engine vehicles, it has become necessary to operate the cooling fan separately from the engine even in medium and large-sized vehicles. However, because the internal combustion engine of medium- and large-sized cars generates more heat than small cars,
Since a large amount of cooling air is required to cool this heat exchanger, there are problems in that the electric fan becomes large and its power consumption increases, so it is not preferable in terms of vehicle installation. do not have.

On the other hand, as disclosed in, for example, Japanese Utility Model Publication No. 49-40183 and Japanese Utility Model Application Publication No. 58-136621, there have been devised systems in which a hydraulic motor is rotated by a hydraulic pump to drive a cooling fan. This requires a dedicated hydraulic pump to supply working fluid to the hydraulic motor that drives the cooling fan, which poses a problem in that the cooling system becomes complicated and large.

(Problems to be Solved by the Invention) The present invention has been made in view of the above points, and its purpose is to simplify the system in which a cooling fan is driven by a hydraulic pump and a hydraulic motor. It is.

Therefore, the present inventors investigated the current power steering device (a device that drives a steering mechanism by supplying pressure oil from a hydraulic pump to a power cylinder, hereinafter referred to as a power steering device).
We focused on the use of a hydraulic pump (abbreviated as P/S) and conducted a study, and found that when driving the P/S device and the hydraulic motor together, there is a negative effect on the steering of the P/S device, such as the steering force. It was found that this resulted in an increase in the amount of water and a worsening of the steering sensation.

In view of the above points, the present invention provides a hydraulic motor that rotates a cooling fan and a P/S device using a single hydraulic pump.
Moreover, it is an object of the present invention to provide a cooling system for a vehicle that operates without impairing the functions of both.

(Means for Solving the Problems) The present invention provides, as a means for solving the above problems, a cooling system for a vehicle in which a cooling medium is cooled by a heat exchanger using a cooling fan. a hydraulic pump for supply; a discharge flow rate control means for controlling the flow rate of fluid discharged and supplied from the hydraulic pump; a hydraulic motor driven to rotate; a flow rate control means provided in a flow path from the hydraulic motor to the steering mechanism to control the flow rate of working fluid supplied from the hydraulic motor to the steering mechanism; A bypass passage that communicates the upstream and downstream sides of the hydraulic motor to bypass the hydraulic motor and circulate a working fluid, and a flow rate switching means that controls the flow area of the bypass passage. The cooling fan is rotationally driven by a motor to cool the heat exchanger.

(Operation) According to the above means, by selectively switching and controlling the supply fluid to the hydraulic motor for the cooling fan or the steering mechanism by the flow rate switching means, the cooling fan steering mechanism and the hydraulic motor are connected to one hydraulic pump. Moreover, when the steering mechanism is operated, pressure working fluid can be supplied preferentially.

Furthermore, according to the above configuration, when the cooling load of the cooling system is large, the discharge flow rate control means increases the flow rate of the working fluid discharged and supplied from the hydraulic pump, and the flow rate switching means of the bypass path increases the flow rate of the working fluid discharged and supplied from the hydraulic pump. The flow rate supplied to the hydraulic motor is increased, and the rotational speed of the cooling fan rotationally driven by the hydraulic motor is increased (controlled) to efficiently cool the heat exchanger.Also, when the cooling load is small etc., the flow rate switching means controls the flow rate in the bypass passage to increase according to the cooling load, and by reducing the flow rate flowing to the liquid motor, the rotation speed of the cooling fan rotationally driven by the motor is controlled. or stop the rotation of the cooling fan. At this time, the discharge flow rate control means reduces the flow rate of the working fluid discharged and supplied from the liquid pump according to the cooling load (compared to when the cooling load is large). to control.

(Effects of the Invention) As described above, since the steering mechanism and the hydraulic motor for the cooling fan can be driven by one pressure reducing pump, the cooling system can be simplified and the hydraulic motor can be used. This makes it possible to achieve high efficiency and high output rotation with a small size.

Additionally, in general, steering mechanisms require a large amount of working fluid and high pressure when steering when the vehicle is stopped (steering when the vehicle is stopped), when driving at low speeds, etc.
In such a case, the amount of heat generated by the internal combustion engine is generally small, so there is no need to drive the cooling fan at high speed. Therefore, the working fluid discharged from the hydraulic pump can be mainly supplied to the steering mechanism.

Conversely, at medium and high speeds, the steering angle and steering angular velocity are small, and the wheels are in rolling contact with the road surface, so there is no need to supply a large amount of working fluid and high pressure to the steering mechanism.
A hydraulic motor for the cooling fins can be supplied with working fluid.

By switching to a mechanism or a hydraulic motor for a cooling fan, it becomes possible to efficiently utilize the working fluid without impairing the functions of both.

Furthermore, the time required for steering generally ranges from a few seconds at the shortest to several tens of seconds at the longest. In addition, since the heat capacity of the heat exchanger and cooling medium is relatively large, even if the cooling air stops, the temperature of the cooling medium will not rise suddenly for several minutes, so both the steering mechanism and the hydraulic motor for the cooling fan When operation is required, the working fluid is preferentially supplied only to the steering mechanism, and even if the supply to the cooling fan hydraulic motor is stopped during that time, the temperature of the cooling medium does not rise rapidly. Therefore, both can be effectively driven by one pump.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a schematic hydraulic circuit diagram of a first embodiment showing the basic configuration of the present invention.

In the middle of the pipe leading from the vane-type, gear-type, piston-type, etc. hydraulic pump 15 that is rotationally driven by an engine (not shown) to the power cylinder of the power steering device (hereinafter referred to as P/S device) 16, there is a pipe that is rotated by hydraulic pressure. driven,
Hydraulic motor 1, such as gear type, vane type, piston type, etc.
7 are connected in series.

A cooling fan 18 that generates cooling air is rotatably connected to the rotational drive shaft of the hydraulic motor 17, and the hydraulic motor 17 is fixedly supported by a fan shroud (not shown) via a fixing stay. . On the upstream side of the cooling air generated by the cooling fan 18, a condenser 19, which is a heat exchanger that cools air conditioner (A/C) refrigerant, and a radiator 20, which is a heat exchanger that cools engine cooling water, are arranged. It is set up.

Further, a discharge flow rate adjusting valve 2 is provided on the discharge side of the hydraulic pump 15.
1 is provided. As shown in FIG. 2, the discharge flow rate regulating valve 21 is activated by the hydraulic pump 15 as the engine speed NE increases.
When the discharge flow rate Q0 becomes equal to or higher than the predetermined flow rate 01, a part of the hydraulic oil is drained into the oil tank to increase the predetermined flow rate Q1.
Adjust so that the P/S device 16 or hydraulic motor 1
Supply to 7. Further, this regulating valve 21 controls the variable throttle area inside the regulating valve 21 in two stages by means of a solenoid 22 which is an electromagnetic means, and controls and changes the predetermined flow rate Q in two stages as shown in FIG. It has become. Predetermined flow rate Q
1 is changed according to the heat dissipation load of the cooling system, and when the heat dissipation load is large, the flow rate is adjusted to a large flow rate, and when the heat dissipation load is normal or the heat dissipation load is small, the flow rate a is adjusted to a small flow rate a.

In the hydraulic circuit diagram of FIG. 1, a first bypass passage A connects the upstream and downstream sides of the hydraulic motor 17 to bypass the hydraulic motor 17 and bypass the working fluid.

A second bypass path B is formed, and this bypass path A
An electromagnetic switching valve 23 is provided as a flow rate switching means. The electromagnetic switching valve 23 has a solenoid 24 which is an electromagnetic means.
．． 25, the flow rate Q of the hydraulic oil flowing through the bypass path A
2 is controlled in three stages.

Thereby, the flow rate Q supplied to the hydraulic motor 17.

is controlled, the hydraulic motor 17 and the cooling fan 18
When the switching valve 23 is in the position, the rotation speed is small, and the switching valve 23 is in the position
When the switch valve 23 is in the position A, the rotation speed is stopped, and when the switching valve 23 is in the position A, the rotation speed is changed to high.

The second bypass path B is provided with a switching valve 26,
This switching valve 26 uses the pressure P1 upstream of the P/S device 16 as a pilot pressure to control the flow 1i Q S of the second bypass path B.
Switch. The switching valve 26 is a spool valve, and the switching valve 26 is designed to prevent the flow rate Q of the bypass path B from changing suddenly during switching operation, that is, the flow rate Q.

The land of the spool is tapered so that it changes continuously. Alternatively, the opening area of the switching boat has a shape (e.g., elongated or triangular) in which the opening area gradually increases continuously. As shown in FIG. 3, when the pilot pressure P1 exceeds a predetermined value, the switching valve 26 switches to a second switch according to the pressure.
The flow rate Q of the bypass path B is changed from zero to the discharge flow rate adjusting valve 21.
The flow rate is continuously switched up to the flow rate Q1 adjusted by. As a result, when a load acts on the P/S device 16 and a steering force is required, the pilot pressure P increases, so that the switching valve 26 adjusts the flow rate Q of the second bypass path B.

and preferentially supply hydraulic oil to the P/S device 16. At this time, the flow rate Q of the second bypass path B.

increases continuously, so there is no sudden change in steering force.
The hydraulic motor 17 can be smoothly switched to the P/S device 16.

Also, downstream of the hydraulic motor 17, that is, from the hydraulic motor 17 to P
A flow rate control valve 27 that controls the flow rate Q4 of the action oil supplied to the P/S device 16 via the hydraulic motor 17 so as to be parallel to the first bypass path A in the middle of the pipe leading to the P/S device 16.
is provided. The flow rate control valve 27 is connected to the P/S device 16
The hydraulic oil supplied to the pump is drained into the oil tank so that it does not exceed a predetermined amount a. Generally, when hydraulic oil flows through the flow control valve 27, there is a pressure loss of 1 to 3 kg/am'', so in the above embodiment, the flow control valve 27
is provided at a position that controls the flow rate only when hydraulic oil is supplied to the hydraulic motor 17, but it may be provided at another position in the flow path from the hydraulic motor 17 to the P/S device 16.

Note that the steering wheel 31 includes a steering angle sensor,
Steering sensor 3 such as a steering angular velocity sensor and a steering torque sensor
2 continues, and the signal from the steering sensor 32 causes the electric control unit 33 (hereinafter referred to as ECU) to control whether or not the steering is being performed.
Determine nothing. ECU33 is A/C capacitor 19
A pressure sensor 34 that detects the refrigerant pressure of the radiator 2o
Heat dissipation from the heat exchanger is performed based on signals from a water temperature sensor 35 that detects the cooling water temperature of The load (cooling load required of the cooling system) is determined as shown in Table 1.

Table 1 [In other words, the ECU 30 determines the heat radiation load as large, medium, small, or extremely small as shown in Table 1 above, and the water temperature sensor 35
When the water temperature sensor 35 is 90℃ or higher, it is a big problem.10
1 small when the water temperature sensor 35 is 80°C or more and less than 90°C or the compressor switch 36 is ON;
When the water temperature sensor 35 is below 80° C. and the compressor switch 36 is OFF, it is determined that the temperature is one minimum.

In addition, water temperature sensor 35. of Table 1 above. It goes without saying that the detected value of the pressure sensor 34 changes depending on the cooling system of various vehicles.

Next, based on the above configuration and the heat radiation load shown in Table 1,
Its operation is explained in Table 2.

Here, Q indicates the flow rate discharged from the hydraulic pump 15 and downstream of the discharge flow rate regulating valve 21 as described above, and EC
By controlling the energization of the solenoid 22 by U33, the normal flow rate a occurs when the energization is OFF, and the large flow rate b when the energization is ON.
) is controlled by This characteristic has already been shown in FIG. 2, and the flow rate a is set to the flow rate required by the P/S device 16 for steering. The flow rate Q2 indicates the flow rate flowing through the first bypass path A, and when the solenoids 24 and 25 are energized, the flow rate changeover valves 23
completely closes the flow area of the first bypass path A.

Fully open, switch to an area where a predetermined flow rate C (<a) flows.

The flow rate Q3 is the flow rate supplied to the hydraulic motor 17,
Flow rate Q of the first bypass passage A or the second bypass passage B
! ,Q,.

Flow rate QJ indicates the flow rate of the hydraulic fluid discharged from the hydraulic motor 17 downstream of the flow rate control valve 27, and flow rate Q indicates the flow rate of the hydraulic oil supplied to the P/S device 16. In addition, the following Table 3 shows the energization control of each solenoid 22, 24, and 25 corresponding to the above-mentioned Table 2.

(Margin below.

Table 3 In Table 2, in the case of pattern ■, that is, with steering, the second
The switching valve 26 of the bypass path B is opened, and the hydraulic pump 15
The hydraulic pressure discharged from the pump is bypassed and preferentially supplied to the P/S device 16 without reaching the hydraulic motor 17. As a result, the hydraulic motor 17 and the cooling fan 18 temporarily stop rotating, and the hydraulic pressure supplied to a power cylinder (not shown) of the P/S device 16 performs steering.

In the case of patterns ■ to ■, that is, when there is no steering, radiator 20. EC based on the heat dissipation load of the capacitor 19
U33 controls the discharge flow rate adjustment valve 21 and the electromagnetic switching valve 23 of the first bypass path A.

In the case of pattern H, that is, when the heat dissipation load is large, the discharge flow rate regulating valve 21 reduces the flow rate trained to the oil tank to control the flow IQ+ to a large flow rate b (larger than the normal flow rate a), and the electromagnetic switching The valve 23 is controlled to the valve position A, that is, fully open. Therefore, the hydraulic pressure discharged from the hydraulic pump 15 is not bypassed and is directly supplied to the hydraulic motor 17 at a large flow rate.
8 at high speed to generate a large amount of cooling air,
Capacitor 19. The radiator 20 cools the refrigerant and cooling water. At this time, the large flow amount of hydraulic oil used and discharged by the hydraulic pump 15 is reduced to a flow rate a by the flow rate control valve 27 and then supplied to the P/S device 16.

In the case of patterns m, rv', and v, that is, in a heat dissipation load.

When the discharge flow rate adjustment valve 21 is small or extremely small, the discharge flow rate adjustment valve 21 sets the flow rate Q.

is controlled to the normal flow rate a (<b), and the current switching valve 23 of the first bypass path A is controlled to the valve positions A, 9, and 8 according to the heat dissipation load of each pattern III, IV', and V. Therefore, the flow rate Q of the first bypass path depends on each pattern.
2 is supplied to Q-c-a, respectively, and the flow rate supplied to the hydraulic motor 17 is controlled to Q3, respectively, to a-a-C. Controlled by rotation speed, low rotation speed, and stop.

As mentioned above, the discharge flow rate adjustment valve 21 and the electromagnetic switching valve 23
The flow rate Q3 supplied to the hydraulic motor is switched and controlled according to the heat dissipation load, and the cooling fan 18 is rotationally driven. The flow rate Q6 supplied to the pump is configured to satisfy a predetermined amount a so that the hydraulic oil always flows. Therefore, when the P/S device 16 operates, the flow rate Q is constant, so a stable steering output torque can be obtained with a constant steering torque. As shown in Figure 4, this is assumed to be P/
The flow rate Q supplied to the S device 16 is not constant, and a, b
If the output torque of the P/S device 16 is to be kept constant, the steering torque for steering the steering wheel 31 will change; however, in the above configuration, the flow rate Q6 is constant ( Since it is a), the steering torque is constant and a stable steering feeling can be obtained. In addition, in the above configuration, since the hydraulic oil in the piping leading to the P/S device 16 is constantly flowing, no air bubbles are generated in the hydraulic oil, and there is no delay in the operation of the P/S device 16 due to air bubbles, which improves responsiveness. Good steering power can be ensured.

In the above configuration, the steering torque is constant regardless of the vehicle speed, but the flow rate control valve 27 is an electromagnetic type to control the flow rate Q.
It goes without saying that by changing a and Q6, the steering torque can be changed according to the vehicle speed.

Next, the heat dissipation load determination circuit in the above-mentioned embodiment ECV 33 will be explained based on FIG.

The output signal of the water temperature sensor 35 is sent to the comparators 51 and 52.
．． The comparator 51 is connected to the non-inverting input terminal of the comparator 51.
, 52.53 The reference power supply Vcc is connected to the inverting input terminal via a predetermined resistor, and the water temperature sensor 35 is connected to ioo°C.
As mentioned above, when the temperature exceeds 90°C or 80°C, the output of each comparator 51, 52° 53 becomes 1" level.A/
The A/C pressure sensor 34 is connected to the non-inverting input terminal of the comparator 54, and the A/C pressure sensor 34 is connected to the 1.
When the pressure exceeds 5Mpa, the output of the comparator 54 becomes “1”.
When the compressor switch 36 is turned on, the output of the amplifier 55 becomes the "1" level.

The output terminal of the comparator 51 is connected to an amplifier 56 and an OR circuit 57, and the output terminals of the comparators 52 and 54 are both connected to an input terminal of an OR circuit 58. OR
The output terminal of the circuit 58 is connected to the input terminal of the OR circuit 570, and the output terminal of the OR circuit 57 is connected to the amplifier 60. The output terminals of the comparator 53 and the amplifier 55 are connected to the input terminal of an OR circuit 59, and the output terminal of the OR circuit 59 is connected to an amplifier 61. Each amplifier 56, 60.61 has a solenoid 22
．． Connected to 24.25. Therefore, the ECU 33 determines the heat dissipation load as shown in Table 1, and controls the energization of solenoids 22° and 24.25 as shown in Table 3.

Next, a second embodiment will be described based on FIG.

The difference from the first embodiment is that a variable capacity oil pump 40 is provided as a hydraulic pump, a variable throttle valve 42 controlled by a solenoid 41 is provided as an electromagnetic switching valve for the first bypass path A, and the second bypass path B and The switching valve 26 is connected to the flow control valve 2.
7 was connected upstream.

The discharge flow rate of the variable displacement pump 40 is determined by the water temperature sensor 35.
．． Pressure sensor 34. Depending on the heat radiation load determined by the ECU 33 based on the signal of the compressor switch 36,
It is continuously controlled by a capacity controller 43. Similarly, the variable throttle valve 42 continuously controls the flow rate of the first bypass path A using the solenoid 41. The orientation, other configurations, and operations are the same as those of the previous embodiments, so explanations will be omitted.

In the above configuration, in controlling the rotational speed of the hydraulic motor 17 and the cooling fan 18, the variable displacement hydraulic pump 40 changes the discharge flow rate from the pump as necessary, and the variable throttle valve 42 controls the first bypass path A. The flow rate is continuously controlled. For this reason, the hydraulic pump does not discharge surplus flow, and the hydraulic motor 17 only discharges the necessary flow.
This method has the advantage that the driving power of the hydraulic pump 40 can be reduced and energy efficiency can be improved. Further, the rotation speed of the hydraulic motor 17 can also be controlled to change continuously.

Also, when hydraulic oil flows through the second bypass path B (i.e., P/
When the S device 16 is in operation), the hydraulic fluid flows through the flow control valve 27.
Therefore, the P/S device 16 is never supplied with more than a predetermined flow rate. Therefore, as described above, there is an advantage that the steering feeling is improved.

In addition, in the above-mentioned embodiment, the first. Although the second bypass paths A and B are provided, one bypass path communicates the upstream and downstream of the hydraulic motor to bypass the hydraulic motor and circulate the hydraulic oil, and one flow rate switching valve is installed in the middle of the bypass path. The flow rate switching valve may be preferentially switched depending on whether or not the P/S device is being steered, and the switching may be controlled depending on the heat radiation load of the heat exchanger.

[Brief explanation of drawings]

FIG. 1 is a hydraulic circuit diagram showing a vehicle cooling system according to a first embodiment of the present invention, FIG. 2 is a flow characteristic diagram of the discharge flow rate regulating valve shown in FIG. 1, and FIG. FIG. 4 is a characteristic diagram for explaining the steering characteristics of the P/S device, and FIG. 5 is a hydraulic circuit diagram showing a second embodiment of the present invention. 15... Hydraulic pump, 16... Power steering device, 17... Hydraulic motor, 18... Cooling fan, 1
9... A/C capacitor, 20... radiator,
21...Discharge flow rate adjustment valve, 22...Solenoid, 2
3...Solenoid switching valve, 24.25...Solenoid, 2
6...Switching valve, 27...Flow control valve, 31...Steering, 32...Steering sensor, 33...ECU
, 34... pressure sensor, 35... water temperature sensor, 36
Compressor switch, 40 Variable displacement hydraulic pump, 41 Solenoid, 42 Variable throttle valve, 43 Capacity control device. Procedural amendment (scissors August 7, 1985 No. 91965 2 Name of invention Vehicle cooling system 3 Person making the amendment a Relationship with cattle Patent applicant Aishi Slimming Tofuyu City Showa-cho 1-1 (426) Nippondenso Co., Ltd. Representative Kengo Toda 4th Director Mr. 1-1-5 Showa-cho, Aimiryoku-shi 448 Date of amendment order Sent date July 30, 1985 6, Subject of amendment A column for a brief explanation of the drawings in the specification. 7. Contents of the amendment In the 9th line of page 24 of the specification, between “ha” and “the present invention,” there is a line that reads “Circuit of a heat dissipation load determination circuit for determining heat dissipation load.” Figure, 6th
Insert the picture.

Claims (1)

[Claims] In a vehicle cooling system in which a cooling medium is cooled by a heat exchanger using a cooling fan, there is a hydraulic pump that supplies working fluid to the wheel steering mechanism, and a discharge flow rate that controls the flow rate of the fluid discharged and supplied from the hydraulic pump. a control means, a hydraulic motor connected in series with the steering mechanism and rotationally driven by the supply of working fluid from the hydraulic pump, and provided in a flow path from the hydraulic motor to the steering mechanism. flow rate control means for controlling the flow rate of working fluid supplied from the hydraulic motor to the steering mechanism; and a flow rate control means that communicates upstream and downstream of the hydraulic motor to bypass the hydraulic motor and circulate the working fluid. and a flow rate switching means for controlling the flow area of the bypass passage, and the cooling fan is rotationally driven by the hydraulic motor to cool the heat exchanger. cooling system.