JP2792185B2 - Vehicle air conditioner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an air conditioner for a vehicle using hydraulic oil of a hydraulic device as a heat source for heating.

2. Description of the Related Art FIG. 1 shows an example of a refrigeration cycle of a vehicle air conditioner using hydraulic oil of a hydraulic device as a heat source.

In the refrigeration cycle 1, a cooling circulation path through which the refrigerant circulates during the cooling operation and a heating circulation path through which the refrigerant circulates during the heating operation are formed. The heating circulation path includes the refrigerant and hydraulic oil for hydraulic equipment. An outdoor heat exchanger 16 for exchanging heat with the heat is provided.

When the cooling mode is selected, the solenoid valve 9 and the solenoid valve 14 arranged in the heating circulation path are closed, and the solenoid valve 13 arranged in the cooling circulation path is opened.

Therefore, the refrigerant flowing through the cooling circulation path is the refrigerant compressor 3 → the refrigerant condenser 5 → the cooling decompression device 7 → the indoor heat exchanger 6
→ circulate through solenoid valve 13 → liquid receiver 18 → refrigerant compressor 3.

When the heating mode is selected, the solenoid valves 9 and 14
Is opened, and the solenoid valve 13 is closed.

Therefore, the refrigerant flowing through the heating circulation path is the refrigerant compressor 3 → the refrigerant condenser 5 → the solenoid valve 9 → the indoor heat exchanger 6 → the solenoid valve
14 → heating decompression device 15 → outdoor heat exchanger 16 → liquid receiver 18 → circulate through refrigerant compressor 3.

During the heating operation, when the temperature of the intake air of the indoor heat exchanger 6 rises above the set temperature, the heating thermistor 23 detects the current, and the energization of the electromagnetic clutch 2 is stopped via the control circuit 21 to compress the refrigerant. The driving of the machine 3 stops. When the suction air temperature of the indoor heat exchanger falls below the set temperature, the electromagnetic clutch 2 is energized again, and the refrigerant compressor 3 is driven.

[Problems to be Solved by the Invention] In the refrigeration cycle 1, when the refrigerant compressor 3 is stopped by turning off the operation mode during the heating operation, or based on the suction air temperature of the indoor heat exchanger 6, refrigerant compression is performed. When the compressor 3 is stopped, for a while after the refrigerant compressor 3 is stopped, a pressure difference is generated across the heating decompression device 15, so that the refrigerant condensed in the indoor heat exchanger 6 is removed from the outdoor heat exchanger. 16
Flow into In this case, particularly in an air conditioner that requires a large capacity, when the oil-side heat absorption increases, the amount of refrigerant passing through the heating decompression device 15 increases, so that the refrigerant is rapidly abrupt inside the outdoor heat exchanger 16. And causes a sharp rise in the low pressure side pressure.

As a result, there is a problem that the durability of the suction valve of the refrigerant compressor 3 is reduced. When the intermittent operation cycle of the refrigerant compressor 3 based on the suction air temperature of the indoor heat exchanger 6 is short, the refrigerant compressor 3 is restarted before the low-pressure side pressure is not sufficiently reduced, which poses a particular problem.

Further, if the refrigerant replenishment operation is performed immediately after the refrigerant compressor 3 stops, the refrigerant replenishment can is adversely affected.

The present invention has been made based on the above circumstances, and an object of the present invention is to provide a vehicle air conditioner that can prevent a sudden increase in low-pressure side pressure after a refrigerant compressor stops.

Means for Solving the Problems In order to achieve the above object, the present invention provides a refrigerant compressor that compresses and discharges a sucked refrigerant, and is provided in the refrigerant compressor. An electromagnetic clutch that transmits to the refrigerant compressor, an indoor heat exchanger that is connected downstream of the refrigerant compressor and exchanges heat between the supplied refrigerant and surrounding air, and that is connected upstream of the refrigerant compressor. An outdoor heat exchanger for exchanging heat between the supplied refrigerant and hydraulic oil of a hydraulic device, and a refrigerant passage connecting the indoor heat exchanger and the outdoor heat exchanger, and provided upstream of the outdoor heat exchanger. Provided a pressure reducing device, provided upstream of the pressure reducing device, an electromagnetic valve for opening and closing the refrigerant passage, and a control circuit for controlling the energization of the electromagnetic clutch and the electromagnetic valve, this control circuit, Stop power supply to electromagnetic clutch Accordingly, it is a technical means to control the energization of the solenoid valve so as to shut off the refrigerant passage.

[Operation and Effect of the Invention] The vehicle air conditioner of the present invention having the above-described configuration includes a control circuit that controls the energization of the electromagnetic clutch and the electromagnetic valve, and when the energization to the electromagnetic clutch is stopped by the control circuit. Then, the energization control of the solenoid valve is performed so as to shut off the refrigerant passage.

Thus, even if the refrigerant compressor is stopped due to the stoppage of energization of the electromagnetic clutch, the electromagnetic valve provided upstream of the decompression device shuts off the refrigerant passage, so that the outdoor heat exchanger located downstream of the decompression device can be used. No refrigerant flows in. As a result,
It is possible to prevent a sharp rise in the low pressure side pressure after the refrigerant compressor is stopped, and to suppress a decrease in durability of the suction valve of the refrigerant compressor.

Next, a vehicle air conditioner of the present invention will be described based on an embodiment shown in the drawings.

 FIG. 1 is a refrigeration cycle of an air conditioner for a vehicle.

The air conditioner of the present embodiment is applied to, for example, a vehicle equipped with a civil engineering construction machine such as a crane.

The refrigeration cycle 1 of the air conditioner includes a refrigerant compressor 3 that is driven by a vehicle engine (not shown) via an electromagnetic clutch 2.

Downstream of the refrigerant compressor 3, a refrigerant condenser 5 is provided which receives high-pressure, high-pressure refrigerant discharged from the refrigerant compressor 3 by condensing and liquefying the refrigerant fan 4 during cooling operation.

The condenser fan 4 is driven when the pressure of an indoor heat exchanger 6, which will be described later, rises to a predetermined value or more during the cooling operation and the heating operation.

Downstream of the refrigerant condenser 5, a cooling decompression device 7 and an electromagnetic valve 9 for opening and closing a bypass 8 that bypasses the cooling decompression device 7 are provided.

Downstream of the cooling decompression device 7 and the solenoid valve 9, heat exchange is performed between the refrigerant decompressed and expanded by the cooling decompression device 7 and the surrounding air during the cooling operation, and passes through the solenoid valve 9 during the heating operation. An indoor heat exchanger 6 for exchanging heat between the supplied high-temperature, high-pressure gaseous refrigerant and the surrounding air is provided. The air that has been heat-exchanged with the refrigerant in the indoor heat exchanger 6 during the cooling operation and the heating operation is blown into the vehicle interior as cold air and hot air by the operation of the indoor fan 10.

Downstream of the indoor heat exchanger 6, a cooling passage 11 through which the refrigerant passes during the cooling operation and a heating passage (the refrigerant passage of the present invention) 12 through which the refrigerant passes during the heating operation are provided in parallel. Solenoid valves for opening and closing the cooling passage 11 and the heating passage 12 are provided in the cooling passage 11 and the heating passage 12, respectively.
13 and 14 are provided.

In the heating passage 12, a heating decompression device 15 is disposed downstream of the solenoid valve 14, and further downstream of the heating decompression device 15, a refrigerant decompressed and expanded by the heating decompression device 15 and a vehicle An outdoor heat exchanger 16 for exchanging heat with hydraulic oil of a hydraulic device (not shown) mounted on the vehicle is provided.

The outdoor heat exchanger 16 is connected via an oil passage 17 to an oil tank (not shown) for storing hydraulic oil for hydraulic equipment, and an oil temperature raising device (not shown) provided in the oil passage 17. )
The hydraulic oil whose temperature has been increased by the above is supplied.

Between the junction of the cooling passage 11 and the heating passage 12 and the refrigerant compressor 3, there is provided a liquid receiver 18 for storing the liquid refrigerant and causing the refrigerant compressor 3 to suck the gas refrigerant. ing.

In the refrigeration cycle 1, pressure switches 19 and 20 are provided downstream of the refrigerant condenser 5 and downstream of the solenoid valve 9 provided in the bypass passage 8, respectively.

The pressure switch 19 is turned off when the high pressure in the cycle, that is, the condensing pressure of the refrigerant, exceeds a set value during the cooling operation, thereby cutting off the power supply to the electromagnetic clutch 2.

The pressure switch 20 is turned on when the pressure of the indoor heat exchanger 6 rises to a predetermined value or more during the heating operation, thereby supplying electricity to the condenser fan 4 via the control circuit 21.

A cooling thermistor 22 for detecting the temperature of the air blown from the indoor heat exchanger 6 and a heating thermistor 23 for detecting the temperature of the intake air of the indoor heat exchanger 6 are provided in the air passage of the indoor heat exchanger 6. Have been.

The above-described electromagnetic clutch 2, condenser fan 4, indoor fan 10, electromagnetic valve 9, electromagnetic valve 13, and electromagnetic valve 14 are controlled to be energized via a control circuit 21. The solenoid valve 9, the solenoid valve 13, and the solenoid valve 14 open when energized, and close when deenergized.

 FIG. 2 shows an electric circuit diagram according to the present invention.

When the pressure switch 19 is turned on, the electromagnetic clutch 2 is energized through a relay 25 based on signals of an operation mode switch 24, a cooling thermistor 22, and a heating thermistor 23 that are input to the control circuit 21. You.

The electromagnetic clutch 2 is energized during the heating operation when the temperature of the suction air detected by the heating thermistor 23 is equal to or lower than the set temperature, and is stopped when the temperature exceeds the set temperature.

When the operation mode switch 24 is set to the heating mode, the electromagnetic valve 14 that opens and closes the heating passage 12 is energized via the relay 26 only when the contact point of the relay 25 is on.
Therefore, even when the heating mode is selected, when the suction air temperature detected by the heating thermistor 23 exceeds the set temperature or the pressure switch 19 is turned off,
When the power supply to the electromagnetic clutch 2 is stopped, the electromagnetic valve 14
Power supply to is also stopped.

The solenoid valve 9 is energized and opened only when the heating mode is selected, and the solenoid valve 13 is energized and opened only when the cooling mode is selected.

Here, the operation of the control circuit 21 for controlling the energization of the electromagnetic clutch 2 and the electromagnetic valve 14 will be described with reference to the flowchart shown in FIG.

First, in step S1, it is determined whether the operation mode switch 24 is in the heating mode.

If the determination result of step S1 is NO, it means the cooling mode or the OFF mode. In the case of the cooling mode, a program for the cooling operation is executed. In the OFF mode, power is not supplied to the electromagnetic clutch 2 and the electromagnetic valve 14.

If the decision result in the step S1 is YES, in a step S2, the electromagnetic clutch 2 and the electromagnetic valve 14 are energized via the relay 25 and the relay 26, and the process proceeds to a step S3.

In step S3, it is determined whether or not the detected temperature of heating thermistor 23 is equal to or lower than a set temperature.

If the decision result in the step S3 is NO, in a step S4,
The energization of the electromagnetic clutch 2 and the electromagnetic valve 14 is stopped, and thereafter, the process returns to step s3.

If the decision result in the step S3 is YES, the process returns to the step S1, and the above program is repeated.

 Next, the operation of this embodiment will be described.

A) When the cooling operation mode is selected.

While the solenoid valve 13 is energized via the control circuit 21,
The solenoid valves 9 and 14 are de-energized. As a result, the cooling passage 11 is opened, and the bypass passage 8 and the heating passage are opened.
12 is shut off by the solenoid valve 9 and the solenoid valve 14.

The high-temperature, high-pressure gaseous refrigerant discharged from the refrigerant compressor 3 is condensed and liquefied by the blower of the condenser fan 4 in the refrigerant condenser 5, decompressed and expanded by the cooling decompression device 7, and supplied to the indoor heat exchanger 6. Supplied.

The refrigerant evaporated by receiving the air from the indoor fan 10 in the indoor heat exchanger 6 flows into the liquid receiver 18 through the cooling passage 11,
The gas refrigerant is sucked into the refrigerant compressor 3.

B) When the heating operation mode is selected.

The solenoid valve 9 and the solenoid valve 14 are energized via the control circuit 21, and the solenoid valve 13 is de-energized. As a result, the bypass passage 8 and the heating passage 12 are opened, and the cooling passage 11 is shut off by the electromagnetic valve 13.

During the heating operation, the condenser fan 4 is de-energized because the pressure switch 20 is off.

Accordingly, the high-temperature, high-pressure gas refrigerant discharged from the refrigerant compressor 3 passes through the refrigerant condenser 5 and is supplied to the indoor heat exchanger 6 through the bypass 8.

The refrigerant condensed and liquefied by receiving the air from the indoor fan 10 in the indoor heat exchanger 6 is decompressed and expanded by the heating decompression device 15 and supplied to the outdoor heat exchanger 16. And in the outdoor heat exchanger 16,
The heat is exchanged with the raised operating oil to evaporate, and the refrigerant is sucked into the refrigerant compressor 3 via the receiver 18.

During the heating operation, the operation mode switch 24 is turned off.
When the mode is set to F, when the detected temperature of the heating thermistor 23 is equal to or higher than the set temperature, or when the pressure switch 19 is turned on, the energization to the electromagnetic clutch 2 is stopped and the energization to the electromagnetic valve 14 is also stopped. Stop.

As a result, even if the operation of the refrigerant compressor 3 stops, the solenoid valve
Since the valve 14 is closed, it is possible to prevent the refrigerant from flowing into the outdoor heat exchanger 16 and prevent the refrigerant from expanding rapidly in the outdoor heat exchanger 16. Therefore, as shown in FIG. 4 (the relationship between the operating oil temperature after the refrigerant compressor 3 is stopped and the low pressure maximum value), the rise of the low pressure side pressure is reduced as compared with the related art, so that the refrigerant compressor 3 Of the suction valve can be prevented from being deteriorated.
Also, when the refrigerant refill operation is performed immediately after the refrigerant compressor 3 is stopped, there is no adverse effect on the refrigerant refill can.

[Brief description of the drawings]

1 is a refrigeration cycle of an air conditioner for a vehicle, FIG. 2 is an electric circuit diagram of the present embodiment, FIG. 3 is a flowchart showing operation of a control circuit, and FIG. 4 is a maximum value of a low pressure side pressure with respect to an oil temperature. FIG. In the figure, 2 ... electromagnetic clutch, 3 ... refrigerant compressor 6 ... indoor heat exchanger, 14 ... electromagnetic valve 16 ... outdoor heat exchanger, 15 ... heating decompression device 21 ... control circuit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model Sho 56-82408 (JP, U) Japanese Utility Model Sho 60-180623 (JP, U) Japanese Utility Model Hei 1-94116 (JP, U) Japanese Utility Model Sho 55- 121716 (JP, U) Japanese Utility Model 62-94116 (JP, U) (58) Fields surveyed (Int. Cl. ⁶ , DB name) B60H 1/02-1/32

Claims (1)

(57) [Claims] (A) a refrigerant compressor for compressing and discharging a sucked refrigerant; and (b) an electromagnetic clutch provided in the refrigerant compressor for transmitting rotation of an engine to the refrigerant compressor when energized. (C) an indoor heat exchanger connected downstream of the refrigerant compressor and exchanging heat between the supplied refrigerant and surrounding air; and (d) an indoor heat exchanger connected upstream of the refrigerant compressor and supplied. (E) an outdoor heat exchanger for exchanging heat between the refrigerant and the hydraulic oil of the hydraulic equipment, and (e) a refrigerant passage connecting the indoor heat exchanger and the outdoor heat exchanger, provided upstream of the outdoor heat exchanger. (F) an electromagnetic valve provided upstream of the pressure reducing device for opening and closing the refrigerant passage; and (g) a control circuit for controlling energization of the electromagnetic clutch and the electromagnetic valve. This control circuit operates when the power supply to the electromagnetic clutch is stopped. And controlling the energization of the solenoid valve so as to shut off the refrigerant passage.