JPH06137148A - Engine cooling device - Google Patents

Abstract

PURPOSE:To control engine cooling water temperature adapting to operating condition of air condenser. CONSTITUTION:A high temperature setting thermostat 23 and a low temperature setting thermostat 24 are provided in parallel in an engine cooling circulating circuit 12, and a solenoid valve 25 is provided in series to the low temperature setting thermostat 24. When the operation rate of a compressor 13 is a set value or more, the solenoid valve 25 is opened so as to make engine cooling water flow toward the low temperature setting thermostat 24 side. It is thus possible to control the engine cooling water temperature rather at a lower level, and also suppress the temperature rise caused by a radiator 21 to a low level so as to suppress the temperature rise in an engine room. When the operation rate of the compressor 13 is lower than the set value, the solenoid valve 25 is closed so as to make engine cooling water flow toward the high temperature setting thermostat 23 side. It is thus possible to control the engine cooling water temperature rather at a higher level so as to improve engine efficiency, and improve room heating performance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine cooling device which rationally controls the engine cooling water temperature according to the operating condition of an air conditioner (air conditioner or cooler).

[0002]

2. Description of the Related Art Instead of controlling the engine cooling water temperature by a conventional thermostat, as described in Japanese Patent Application Laid-Open No. 57-179324, an outside air temperature sensor detects the outside air temperature, and the outside air temperature is detected according to the outside air temperature. By calculating the engine cooling water temperature and controlling the water cock and cooling fan so that the calculated water temperature is reached, the engine cooling water temperature is raised in winter when the outside air temperature is low to improve heating performance and the outside air temperature is high. In summer, the engine cooling water temperature is lowered to suppress the temperature rise in the engine room (intake air temperature rise of the engine).

[0003]

Most automobiles of recent years are equipped with an air conditioner (air conditioner or cooler), and the temperature rise in the engine room is released from the condenser constituting the refrigeration cycle of this air conditioner. The amount of heat has a large effect. Especially in summer, the outside air temperature is high, and the operation rate of the compressor in the refrigeration cycle is high, so the amount of heat released from the condenser is greatly increased. Since the intake air temperature becomes too high, problems such as knocking, reduced fuel consumption, and reduced output tend to occur.

However, in the above-mentioned known example, the engine cooling water temperature is controlled by the outside air temperature regardless of the operating state of the air conditioner, so that the heat radiation from the condenser has no influence on the temperature rise in the engine room. The control is ignored, and the control is not necessarily adapted to the temperature condition in the engine room. Moreover, due to the influence of hot air from the engine rules at idle or at low vehicle speeds,
There is also a drawback that the temperature detected by the outside air temperature sensor is detected higher than it actually is, which lowers the engine cooling water temperature more than necessary and deteriorates fuel consumption.

The present invention has been made in consideration of such circumstances, and its purpose is to replace the conventional outside air temperature detection method with
An object of the present invention is to provide an engine cooling device capable of performing appropriate engine cooling water temperature control in consideration of the operating state of the air conditioner (factor of temperature rise in engine room).

[0006]

In order to achieve the above object, an engine cooling device of the present invention is provided with an engine cooling water circulating circuit for cooling an engine of an automobile equipped with an air conditioner, wherein the engine cooling water circulating circuit is provided. A radiator provided therein, a cooling fan for sending air to the radiator, and a valve mechanism provided in the engine cooling water circulation circuit so that the valve opening temperature can be switched in at least two stages.
An operating state detecting means for detecting an operating state of the air conditioner, a water temperature detecting means for detecting an engine cooling water temperature, a valve opening temperature of the valve mechanism according to an operating state of the air conditioner, and the valve opening temperature. A control means for controlling the operation of the cooling fan in consideration of the engine cooling water temperature is provided.

In this case, as the operating state of the air conditioner detected by the operating state detecting means, the operating rate of the compressor in the refrigeration cycle or the capacity of the variable displacement compressor may be detected.

[0008]

According to the above construction, the operating condition detecting means detects the operating condition of the air conditioner (for example, the operating ratio of the compressor or the capacity of the variable displacement compressor), and uses the detected data as control data. The switching operation of the valve opening temperature of is controlled. Furthermore, the engine cooling water temperature is detected by the water temperature detecting means, and the operation of the cooling fan is controlled in consideration of the engine cooling water temperature and the valve opening temperature.

With such control, in the summer, for example, when the operating rate of the compressor is high, or when the capacity of the variable displacement compressor is large, it is considered that the heat radiation amount from the capacitor is large. Then, the valve opening temperature of the valve mechanism is switched to the low temperature side, and the engine cooling water temperature is controlled to be low. As a result, the temperature rise by the radiator is reduced, and the temperature rise in the engine room is suppressed. In addition, by lowering the engine cooling water temperature, it is possible to reduce the engine head wall temperature around the engine intake port, reduce the intake air temperature rise, and prevent knocking.

On the other hand, in the winter when no cooling is performed, when the operating rate of the compressor is low, or when the capacity of the variable capacity type compressor is small, the amount of heat radiated from the condenser is taken into consideration and the valve is The valve opening temperature of the mechanism is switched to the high temperature side, and the engine cooling water temperature is controlled to be high. This improves engine efficiency and heating performance. In addition, raising the engine cooling water temperature optimizes the temperature of the engine oil and is effective in reducing friction loss.

As described above, if the operating rate of the air conditioner or the capacity of a variable displacement compressor is detected as the operating state of the air conditioner, the control data appropriately reflecting the operating state of the air conditioner is obtained. Can be obtained.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, the configuration of the air conditioner 10 mounted on the automobile will be described. The air conditioner 10 includes a refrigeration cycle 11 and an engine cooling water circulation circuit 12. In the refrigeration cycle 11, the refrigerant discharged from the discharge port 13a of the compressor 13 is condensed into the condenser 14, the receiver 15, and the expansion valve 1.
6 → evaporator 17 → suction port 13 of compressor 13
It circulates in the route of b. As a result, the compressor 13
The high temperature gas refrigerant discharged from the discharge port 13a is radiated by the condenser 14 to be liquefied, and this liquid refrigerant is evaporated by the evaporator 17 to cool the vehicle interior. At this time, the opening degree of the expansion valve 16 is automatically adjusted by the temperature sensing cylinder 18 that detects the refrigerant temperature on the outlet side of the evaporator 17 so that the refrigerant supply amount to the evaporator 17 becomes appropriate. The compressor 13 is driven by the engine 19 via a magnet clutch (not shown).

On the other hand, the engine cooling water circulation circuit 12 is a circuit for circulating the cooling water for cooling the engine 19 to the radiator 21 side by the pump 20 and radiating the cooling water. In this engine cooling water circulation circuit 12,
A valve mechanism 22 that can switch the valve opening temperature in two steps is provided. This valve mechanism 22 is used for the engine cooling water circulation circuit 12
The bypass passage 26 is provided in parallel with the high temperature setting thermostat 23 provided therein, and the low temperature setting thermostat 24 and the solenoid valve 25 are provided in series in the bypass passage 26. In this case, the valve opening temperature of the high temperature setting thermostat 23 is the high temperature setting temperature Tw1 (for example, 93
C.), and the valve opening temperature of the low temperature setting thermostat 24 is set to the low temperature side setting temperature Tw2 (for example, 83.degree. C.).

In this embodiment, the valve mechanism 22 is provided on the downstream side of the radiator 21, and the engine cooling water is
The radiator 21 is bypassed by the radiator bypass circuit 27 until the high temperature side preset temperature Tw1 or higher or the low temperature side preset temperature Tw2 or higher and the solenoid valve 25 opens. In addition, the radiator 21 and the capacitor 1 described above
4 are arranged to face each other, for example, two cooling fans 28
It is designed to be cooled collectively.

These cooling fan 28 and compressor 13
The solenoid valve 25 of the valve mechanism 22 is controlled by an electronic control unit (hereinafter referred to as “ECU”) 29.
Then, the engine cooling water temperature T on the upstream side of the radiator 21
Water temperature sensor 30 which is a water temperature detecting means for detecting w, and refrigerant discharge pressure sensor 3 for detecting the refrigerant discharge pressure of the compressor 13.
1, signals from the blow-out temperature sensor 32 that detects the blow-out temperature of the cool air that has passed through the evaporator 17, the magnet clutch switch 33 of the compressor 13, etc.
Entered in. The magnet clutch switch 33
Is kept on while the compressor 13 is rotating,
It is maintained in the off state during the stop.

The above-mentioned ECU 29 is provided in the compressor 13
Of the magnetic clutch switch 33 is integrated to function as an operation state detecting means for obtaining the operating rate Kc of the compressor 13. Further, by executing the control program shown in FIG. 2, the ECU 29 switches the valve opening temperature of the valve mechanism 22 according to the operating rate Kc of the compressor 13 and considers the valve opening temperature and the engine cooling water temperature Tw. It also functions as control means for controlling the operation of the cooling fan 28.

The control contents of the ECU 29 will be described below with reference to the flowchart of FIG. When the air conditioner switch (not shown) of the air conditioner 10 is turned on by the operation of the passenger, the determination in step S1 becomes "YES",
In step S2, the operating rate Kc of the compressor 13 is calculated based on the signal output from the magnet clutch switch 33 of the compressor 13. Next, it is determined whether or not the operating rate Kc is, for example, 60% or more (step S3). If "YES" (Kc ≧ 60%), the process proceeds to step S4 and the solenoid valve 25 of the valve mechanism 22 is operated. Open the engine cooling water to a low temperature setting thermostat 2
Make it run to side 4. Thereby, after switching the valve opening temperature of the valve mechanism 22 to the low temperature side setting temperature Tw2 = 83 ° C. which is the valve opening temperature of the low temperature setting thermostat 24, the refrigerant discharge pressure sensor 31 is turned on (the refrigerant discharge pressure is, for example, 15 kg / cm2. The above is determined (step S5).

If "YES" in this step S5, that is, if the operation state of the compressor 13 is high load,
Regardless of the engine cooling water temperature Tw, the process proceeds to step S10, the cooling fan 28 is operated at a high speed of, for example, 12 V, and the air volume to the condenser 14 is increased to increase the condenser
Promote heat dissipation of 4. On the other hand, when the refrigerant discharge pressure sensor 31 is off, that is, when the operation state of the compressor 13 is not high load, the process proceeds to step S6, and the engine cooling water temperature Tw detected by the water temperature sensor 30 is Tw2 + 5 ° C. or higher. If yes, "YES" (Tw ≥ Tw2 + 5
C), the engine cooling water temperature Tw is higher than the appropriate temperature, so the process proceeds to step S10, the cooling fan 28 is operated at high speed, and the engine cooling water temperature Tw is lowered.
In step S6, the operation start temperature of the cooling fan 28 is set to the water temperature plus 5 ° C. In step S6, "N
If it is determined to be “O” (Tw <Tw2 + 5 ° C.), the engine cooling water temperature Tw is almost the proper temperature, so the process proceeds to step S11, the cooling fan 28 is operated at a low speed of, for example, 6 V, and the engine cooling water temperature Tw is reached. Is maintained near the low temperature side set temperature Tw2.

On the other hand, if "NO" in the above step S3, that is, if the operating rate Kc of the compressor 13 is less than 60%, the process proceeds to step S7, and the solenoid valve 25 of the valve mechanism 22 is closed. The engine cooling water is made to flow to the high temperature setting thermostat 23 side. As a result, the valve opening temperature of the valve mechanism 22 is switched to the high temperature side set temperature Tw1 = 93 ° C. which is the valve opening temperature of the high temperature setting thermostat 23. Next, in step S8, it is determined whether the engine cooling water temperature Tw detected by the water temperature sensor 30 is Tw1 + 5 ° C. or higher, and if “NO” (Tw <Tw1 + 5 ° C.),
Since the engine cooling water temperature Tw is lower than the appropriate temperature, the process proceeds to step S12, the cooling fan 28 is stopped, and the engine cooling water temperature Tw is increased. On the other hand, if “YES” in the step S8 (Tw ≧ Tw1 + 5 ° C.), the process proceeds to a step S9, and it is determined whether the engine cooling water temperature Tw is overheat limit, for example, 110 ° C. or more, and “Y
If “ES” (Tw ≧ 110 ° C.), the engine cooling water temperature Tw is higher than the appropriate temperature, so the process proceeds to step S10, the cooling fan 28 is operated at high speed, and the engine cooling water temperature Tw is reduced. In step S9, "NO" (T
If w <110 ° C.), the engine cooling water temperature Tw is almost the proper temperature, so the process proceeds to step S11, the cooling fan 28 is operated at a low speed, and the engine cooling water temperature Tw is maintained near the high temperature side set temperature Tw1. To do.

According to the present embodiment described above, when the operation rate of the compressor 13 is high in summer, etc., the valve opening temperature of the valve mechanism 22 is set in consideration of the large amount of heat radiation from the condenser 14. Switch to the low temperature setting temperature Tw2,
Since the engine cooling water temperature Tw is controlled to be low, the temperature rise by the radiator 21 can be made small and the temperature rise in the engine room can be suppressed. As a result, the intake air temperature of the engine 19 can be appropriately maintained even when the operation rate of the compressor 13 is high in summer and the like, knocking can be prevented, and fuel consumption and output can be improved. Moreover, it is possible to improve the heat resistance condition of the accessory parts in the engine room.

On the other hand, the condenser 1 is used in the winter when the cooling is not performed and in other seasons when the operation rate of the compressor 13 is low.
Considering that the amount of heat radiated from 4 is small, the valve opening temperature of the valve mechanism 22 is switched to the high temperature side set temperature Tw1 to control the engine cooling water temperature Tw to be higher. As a result, the amount of heat released from the radiator 21 can be increased, and the heating performance can be improved. Further, if the engine cooling water temperature Tw is increased, engine efficiency can be improved and friction loss due to engine oil or the like can be reduced.
Moreover, the temperature difference between the engine cooling water temperature Tw and the cooling air temperature of the cooling fan 28 increases, the cooling efficiency of the radiator 21 improves, and the alternator load can be reduced by reducing the operating rate of the cooling fan 28. Combined with this, it is possible to improve fuel efficiency.

The compressor 13 of this embodiment is designed to change the operating rate according to the cooling load.
A variable capacity compressor that changes the capacity of the compressor depending on the cooling load may be used. In this case, when the capacity of the compressor is large, the valve opening temperature of the valve mechanism 22 is switched to the low temperature setting temperature Tw2, and when the capacity of the compressor is small, the valve opening temperature of the valve mechanism 22 is set to the high temperature setting temperature Tw1. Just switch it. In addition, the valve mechanism 2
The switching of the valve opening temperature of No. 2 is not limited to two steps, but may be changed in three steps or more or continuously to improve the control accuracy.

Further, the control data used for the switching control of the valve opening temperature of the valve mechanism 22 is not limited to the operating rate and capacity of the compressor 13, and for example, the heat radiation temperature of the condenser 14, the refrigerant discharge pressure of the compressor 13 and the refrigerant. The temperature or the like may be used as the control data, and the point is that the valve opening temperature of the valve mechanism 22 is switched and controlled by using the information reflecting the operating state of the air conditioner 10 as the control data.

Further, although the valve mechanism 22 is provided on the downstream side of the radiator 21 in this embodiment, it may be provided on the upstream side of the radiator 21. Further, the cooling fan 2 may be provided.
The number of 8 is not limited to two, and may be one or three or more.

In addition, according to the present invention, the radiator and the condenser are arranged at different positions without being opposed to each other, and the radiator and the condenser are cooled by separate cooling fans, and the valve mechanism 22 is configured and opened. Various modifications are possible, such as changing the valve temperature set value as appropriate.

[0026]

As is apparent from the above description, according to the present invention, the valve opening temperature of the valve mechanism is switched according to the operating state of the air conditioner, and the valve opening temperature and the engine cooling water temperature are taken into consideration. Since it is configured to control the operation of the cooling fan, it is possible to perform appropriate engine cooling water temperature control in consideration of the operating condition of the air conditioner (factor of temperature rise in the engine room), prevent knocking, improve output, improve engine efficiency. It can contribute to the improvement of fuel efficiency.

In this case, if the operating rate of the air conditioner or the capacity of a variable displacement compressor is detected as the operating state of the air conditioner, control data that properly reflects the operating state of the air conditioner can be obtained. Obtainable.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart showing the flow of control.

[Explanation of symbols]

10 ... Air conditioner, 11 ... Refrigeration cycle, 12 ... Engine cooling water circulation circuit, 13 ... Compressor, 14 ... Condenser, 17 ... Evaporator, 19 ... Engine, 21 ... Radiator, 22 ... Valve mechanism, 23 ... High temperature setting thermostat, 24 ... Low temperature setting thermostat, 25 ... Solenoid valve, 2
6 ... Bypass passage, 28 ... Cooling fan, 29 ... ECU (control means, operating state detecting means), 30 ... Water temperature sensor (water temperature detecting means), 31 ... Refrigerant discharge pressure sensor, 33 ... Magnet clutch switch.

Claims (2)

[Claims] 1. An engine cooling device having an engine cooling water circulation circuit for cooling an engine of an automobile equipped with an air conditioner, comprising: a radiator provided in the engine cooling water circulation circuit; and a cooling fan for sending air to the radiator. A valve mechanism provided in the engine cooling water circulation circuit and capable of switching the valve opening temperature in at least two stages; an operating state detecting means for detecting an operating state of the air conditioner; and a water temperature detecting means for detecting an engine cooling water temperature. And a control means for switching the valve opening temperature of the valve mechanism according to the operating state of the air conditioner and controlling the operation of the cooling fan in consideration of the valve opening temperature and the engine cooling water temperature. An engine cooling device. 2. The operating condition of the air conditioner detected by the operating condition detecting means is to detect the operating rate of the compressor of the refrigeration cycle or the capacity of the variable displacement compressor. The engine cooling device according to claim 1.