JP2988078B2 - Vehicle air conditioner equipped with hydraulic fan - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for a vehicle in which a hydraulic fan generates an airflow passing through an outdoor heat exchanger.

[0002]

2. Description of the Related Art When a refrigerant compressor of a refrigeration cycle operates, a hydraulic fan operates in conjunction therewith to generate an airflow in an outdoor heat exchanger. Alternatively, when the hydraulic fan also serves as a radiator cooling fan in addition to the outdoor heat exchanger of the refrigeration cycle, the hydraulic fan is controlled to have a rotation speed corresponding to the engine cooling water temperature, and when the refrigeration cycle operates. , Is controlled to be higher than a predetermined rotation speed.

[0003]

As shown by solid lines A and B in FIG. 7, the torque applied to the refrigerant compressor changes depending on, for example, the outside air temperature and also changes depending on the rotation speed of the hydraulic fan. For this reason, in the conventional technology in which the rotation speed of the hydraulic fan is set independently of the torque of the refrigerant compressor, the added torque of the torque of the refrigerant compressor and the torque of the hydraulic pump are both large, and the fuel consumption of the engine is reduced. May be larger. That is, when the rotation speed of the hydraulic fan is changed under a certain condition, and when the rotation speed of the hydraulic fan is low, the torque of the refrigerant compressor is high as shown by solid lines A and B in FIG. Fuel consumption increases. Conversely, when the rotation speed of the hydraulic fan is high, the torque of the refrigerant compressor decreases, but the torque of the hydraulic pump increases as shown by the broken line C in FIG. The added torque increases, and the fuel consumption of the engine increases.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an air conditioner for a vehicle equipped with a hydraulic fan capable of reducing the added torque of the torque of the refrigerant compressor and the torque of the hydraulic pump and suppressing the fuel consumption of the engine. It is in.

[0005]

An air conditioner for a vehicle equipped with a hydraulic fan according to the present invention includes a refrigerant compressor driven by an engine and an outdoor heat exchanger for exchanging heat between refrigerant and outdoor air. A refrigeration cycle, a hydraulic pump driven by the engine to generate hydraulic pressure, a hydraulic fan operated by the hydraulic pressure generated by the hydraulic pump to generate an airflow passing through the outdoor heat exchanger, and a hydraulic fan A fan speed varying means for varying a rotation speed, and operating the fan speed varying means so that a torque obtained by adding a torque of the refrigerant compressor and a torque of the hydraulic pump becomes small, thereby rotating the hydraulic fan. A technical means comprising a control circuit for changing the speed was employed.

[0006]

The control circuit operates the fan speed varying means to change the rotation speed of the hydraulic fan even if the torque of the refrigerant compressor changes due to a change in the outside air temperature or other factors.
The added torque of the torque of the refrigerant compressor and the torque of the hydraulic pump is reduced.

[0007]

As described above, the vehicle air conditioner equipped with the hydraulic fan according to the present invention has a small addition torque of the torque of the refrigerant compressor and the torque of the hydraulic pump. Fuel consumption can be reduced.

[0008]

Next, an air conditioner for a vehicle equipped with a hydraulic fan according to the present invention will be described with reference to an embodiment shown in the drawings. FIG. 1 to FIG. 3 show an embodiment of the present invention. FIG. 1 is a schematic structural view of a vehicle air conditioner provided with a hydraulic fan. The air conditioner for a vehicle shown in this embodiment includes a refrigerant evaporator 1 for a front seat and a refrigerant evaporator 2 for a rear seat, and a refrigeration cycle 4 employing a variable capacity refrigerant compressor 3. The configuration of the refrigeration cycle 4 will be briefly described.

The refrigeration cycle 4 includes a refrigerant compressor 3 driven by an engine (not shown), and a refrigerant condenser 5 for exchanging heat between refrigerant discharged from the refrigerant compressor 3 and air outside the vehicle compartment.
The outdoor heat exchanger of the present invention includes a receiver 6 for storing a refrigerant and discharging a liquid refrigerant. The refrigerant discharged from the receiver 6 flows into the front-seat refrigerant evaporator 1 through the front-seat depressurizing device 8 and is blown out to the front-seat side when the electromagnetic valve 7 for switching the air conditioning of the rear seat is closed. After evaporating by exchanging heat with the generated air, the refrigerant is sucked into the refrigerant compressor 3 again. Solenoid valve 7
Is open, the refrigerant discharged from the receiver 6 flows into the rear-seat refrigerant evaporator 2 via the rear-seat depressurizing device 9 at the same time as the refrigerant evaporator 1 for the front seat, and After evaporating by exchanging heat with the air blown to the refrigerant compressor 3 again
Is sucked.

[0010] The refrigerant compressor 3 includes a variable capacity means 10. The displacement variable means 10 of the present embodiment continuously varies the angle of the swash plate 13 for driving the piston 12 in accordance with the balance between the pressure on the refrigerant suction side and the force set by the spring 11, and discharges the refrigerant. Is continuously varied, and as a result, the pressure on the discharge side of the refrigerant compressor 3 is kept within a certain range.

The refrigerant condenser 5 has a hydraulic fan 14 as means for forcibly exchanging heat between the refrigerant and the outdoor air.
The hydraulic fan 14 is a fan driven by hydraulic pressure generated by a hydraulic pump 15, and the hydraulic pump 15 is driven by an engine. Further, a fan speed varying means for varying the rotation speed of the hydraulic fan 14 is provided in a passage for supplying the oil generated by the hydraulic pump 15 to the hydraulic fan 14. The fan speed changing means of the present embodiment is a three-way solenoid valve 16. The discharge flow rate of the hydraulic pump 15 changes according to the opening of the three-way solenoid valve 16, and the rotation speed of the hydraulic fan 14 changes. The opening of the three-way solenoid valve 16 is controlled by the control circuit 17.

The control circuit 17 will be described briefly. The control circuit 17 of the present embodiment is a circuit using a microcomputer, and includes a compressor torque detecting means for detecting the torque of the refrigerant compressor 3 and a pump torque detecting means for detecting the torque of the hydraulic pump 15. Then, the control circuit 17 adds the compressor torque detected by the compressor torque detecting means and the pump torque detected by the pump torque detecting means, and rotates the hydraulic fan 14 such that the added torque becomes small. This is to feedback control the speed. The compressor torque detecting means of the present embodiment calculates the compressor torque applied to the refrigerant compressor 3 from the temperature of the outside air of the vehicle that exchanges heat with the refrigerant condenser 5 and the pressure on the high pressure side of the refrigeration cycle 4. Things. That is, the torque Tc of the refrigerant compressor 3 = f (Pd · Vc) and Vc = g (Pd
・ Calculated from (Tam). F and g are constants, Pd
Is the pressure on the high pressure side of the refrigeration cycle 4, and Tam is the temperature of the outside air of the vehicle that is exchanged with the refrigerant condenser 5. For this reason,
The control circuit 17 includes an outside air sensor 18 that detects the temperature of the outside air of the vehicle compartment that exchanges heat with the refrigerant condenser 5,
Pressure sensor 1 for detecting the pressure on the high pressure side of refrigeration cycle 4
9 is provided. Further, the pump torque detecting means of the present embodiment calculates the pump torque from the rotation speed of the hydraulic fan 14. That is, the pump torque Tf = h (N
It is calculated from f). Here, h is a constant, and Nf is the rotation speed of the hydraulic fan 14. For this reason, the control circuit 17
A rotation sensor 20 for detecting the rotation speed of the hydraulic fan 14 is provided.

Next, an example in which the control circuit 17 performs feedback control of the rotation speed of the hydraulic fan 14 so as to reduce the added torque will be described with reference to the flowchart of FIG. When the air conditioner switch is turned on (start) by the user, first, the rotation speed of the hydraulic fan 14 is rotated at a predetermined rotation speed (for example, 700 rpm) (step S1). Next, the compressor torque and the pump torque at this time are calculated, and the added torque is calculated (step S).
2). Next, the rotational speed of the hydraulic fan 14 is increased by a predetermined amount (for example, 5 rpm, step S3). Subsequently, the compressor torque and the pump torque at this time are calculated, and the added torque is calculated (step S4). Then, the addition torque calculated this time is compared with the addition torque calculated last time, and it is determined whether the current addition torque is lower than the previous addition torque (step S5). If this determination is YES, the process returns to step S3. If the determination is NO, the rotational speed of the hydraulic fan 14 is decreased by a predetermined amount (for example, 5 rpm, step S6). continue,
The compressor torque and the pump torque at this time are calculated, and the added torque is calculated (step S7). Then, the currently calculated addition torque is compared with the previously calculated addition torque, and it is determined whether or not the current addition torque is lower than the previous addition torque (step S8). If this determination is YES, the process returns to step S6, and the determination is NO.
If so, the process returns to step S3.

[Operation of Embodiment] Next, the operation of the above embodiment will be briefly described. When the pressure on the high pressure side of the refrigeration cycle 4 is constant and the outside air temperature is 20 ° C, the air conditioner switch is turned on.
Then, the operation of the hydraulic fan 1
The rotation speed of No. 4 constantly changes so that the added torque obtained by adding the compressor torque and the pump torque becomes small, and as a result, it becomes about 800 rpm which is the minimum torque indicated by the solid line D in FIG.
When the pressure on the high pressure side of the refrigeration cycle 4 is constant and the outside air temperature is 5 ° C., when the air conditioner switch is turned on,
By the operation of the control circuit 17, the rotation speed of the hydraulic fan 14 is constantly changed so that the added torque obtained by adding the compressor torque and the pump torque is reduced, and as a result, the minimum torque of 600 rpm of the solid line E in FIG. become.

[Effects of the Embodiment] As described above, when the air conditioner switch is turned on, the added torque obtained by adding the compressor torque and the pump torque becomes small. As shown by the solid line F in FIG. 4, the hydraulic fan 14 operates at about 800 rpm, and the fuel consumption of the engine can be suppressed. Further, for example, when the outside air temperature is 5 ° C., as shown by a solid line G in FIG.
Operates at about 600 rpm, thereby reducing the fuel consumption of the engine.

[Second Embodiment] FIGS. 5 and 6 show a second embodiment. FIG. 5 is a block diagram of a control circuit 17 for setting the rotation speed of a hydraulic fan. In the present embodiment, the control circuit 17 performs feedforward control of the rotation speed of the hydraulic fan based on the torque of the refrigerant compressor. Therefore, as in the first embodiment, the control circuit 17 includes an outside air sensor 18 that detects the temperature of the vehicle outside air that is heat-exchanged with the refrigerant condenser in order to detect the torque of the refrigerant compressor.
Pressure sensor 19 for detecting the pressure on the high pressure side of the refrigeration cycle
And calculates the compressor torque applied to the refrigerant compressor 3 from the temperature of the outside air and the pressure on the high pressure side of the refrigeration cycle. Then, as shown in the graph of FIG. 6, the rotational speed of the hydraulic fan was set according to the compressor torque, and the rotational speed of the hydraulic fan was set by operating the three-way solenoid valve 16 which is a fan speed varying means. The rotation speed is set.

[Modification] In the above embodiment, an example was shown in which the torque of the refrigerant compressor and the torque of the hydraulic fan (hydraulic pump) were obtained by calculation. good. Although the variable capacity type refrigerant compressor has been described as an example, the present invention is not limited to the variable capacity type, and another type of variable quantity type refrigerant compressor may be used. The refrigeration cycle shown in the embodiment is an example, and the present invention can be applied to all refrigeration cycles using a hydraulic fan, such as a heat pump refrigeration cycle capable of cooling and heating, and a refrigeration cycle having one refrigerant evaporator. When the hydraulic fan also serves as a cooling fan for the radiator, the rotation speed of the hydraulic fan may be controlled in association with the cooling water temperature. The controls and numerical values shown in the embodiment are merely examples, and are not limited to the embodiment. The feedback torque or the other feedforward control may be applied to reduce the added torque or to perform the learning function. May be used.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a vehicle air conditioner including a hydraulic fan (first embodiment).

FIG. 2 is a flowchart showing an operation of a control circuit (first embodiment).

FIG. 3 is a graph showing a relationship between a rotation speed of a hydraulic fan and an added torque (first embodiment).

FIG. 4 is a graph showing a relationship between a rotation speed of a hydraulic fan and fuel consumption (first embodiment).

FIG. 5 is a block diagram of a control circuit for setting a rotation speed of a hydraulic fan (second embodiment).

FIG. 6 is a graph showing a relationship between a compressor torque and a rotation speed of a hydraulic fan (second embodiment).

FIG. 7 is a graph showing the relationship between the rotation speed of the hydraulic fan and the compressor torque, and the relationship between the rotation speed of the hydraulic fan and the pump torque (prior art).

[Explanation of symbols]

 Reference Signs List 3 refrigerant compressor 4 refrigeration cycle 5 refrigerant condenser (outdoor heat exchanger) 14 hydraulic fan 15 hydraulic pump 16 three-way solenoid valve (fan speed variable means) 17 control circuit

Claims (1)

(57) [Claims] 1. A refrigeration cycle including: (a) a refrigerant compressor driven by an engine; an outdoor heat exchanger for exchanging heat between refrigerant and outdoor air; and (b) a hydraulic pressure generated by the engine to generate hydraulic pressure. (C) a hydraulic fan that is operated by hydraulic pressure generated by the hydraulic pump and generates an airflow passing through the outdoor heat exchanger; and (d) a fan speed that varies the rotation speed of the hydraulic fan. (E) operating the fan speed varying means to change the rotation speed of the hydraulic fan so that the torque obtained by adding the torque of the refrigerant compressor and the torque of the hydraulic pump is reduced. A vehicle air conditioner including a hydraulic fan including a control circuit.