JPH03273925A - Air conditioning device for vehicle - Google Patents

Abstract

PURPOSE:To prevent abrupt rise of pressure on low pressure side after a refriger ant compressor stops by controlling supply of power of solenoid valve in such a way that refrigerant passage is shut off when supply of power to an electronic clutch is stopped. CONSTITUTION:The refrigerant cycle 1 of an air conditioning device is provided with a refrigerant compressor 3 which is driven by an engine which drives a vehicle via an electronic clutch 2. On the downstream from the refrigerant compressor 3, a refrigerant condenser 5 is installed for condensing and liquefying high temperature and high pressure refrigerant which is discharged from the refrigerant compressor 3 under blow of air of a fan 4 for condensation during room cooling operation. On the downstream for the refrigerant condenser 5, a pressure reducing device 7 for room cooling and a solenoid valve 9 which opens or closes a by-pass passage 8 which by-passes it are mounted. In this case, a control circuit 21 which controls supply of power to the electronic clutch 2 and solenoid valve 9 is mounted. It controls supply of power to the solenoid valve 9 in such a way that refrigerant passage is shut off when supply of power to the electronic clutch 2 is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a vehicle air conditioner that uses hydraulic oil from hydraulic equipment as a heat source for heating.

[Prior Art] FIG. 1 shows an example of a refrigeration cycle for a vehicle air conditioner that uses hydraulic oil of hydraulic equipment as a heat source.

This refrigeration cycle 1 has a cooling circulation path through which refrigerant circulates during cooling operation, and a heating circulation path through which refrigerant circulates during heating operation. An outdoor heat exchanger 16 is provided to exchange heat between the two.

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

Therefore, the refrigerant flowing through the cooling circulation path is transferred to the refrigerant compressor 3.
→ Refrigerant condenser 5 → Cooling pressure reducing device 7 → Indoor heat exchanger 6-
The solenoid valve 13 - receiver 18 → refrigerant compressor 3 is circulated.

When heating mode is selected, solenoid valve 9 and solenoid valve 14
is in an open state, and the solenoid valve 13 is in a closed state.

Therefore, the refrigerant flowing through the heating circulation path is transferred to the refrigerant compressor 3.
→ Refrigerant condenser 5 → Solenoid valve 9 → Indoor heat exchanger 6 → Solenoid valve 1
4-#Heating pressure reducing device 15→outdoor heat exchanger 16-→liquid receiver 18-→refrigerant compressor 3 is circulated.

During this 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 this, and the control circuit 21 stops energizing the electromagnetic clutch 2 to compress the refrigerant. The drive of machine 3 stops. When the intake air temperature of the indoor heat exchanger 6 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 heating operation, or when the refrigerant compressor 3 is stopped based on the suction air temperature of the indoor heat exchanger 6, When the refrigerant compressor 3 is stopped, a large pressure difference occurs before and after the heating pressure reducing device 15 for a while after the refrigerant compressor 3 is stopped, so the refrigerant condensed in the indoor heat exchanger 6 is transferred to the outdoor heat exchanger 16
flows into.

In this case, especially in an air conditioner that requires a large capacity, if the amount of heat absorbed on the oil side becomes large, the heating pressure reducing device 15
As the amount of refrigerant passing through increases, the refrigerant rapidly engraves inside the outdoor heat exchanger 16, causing a rapid increase in the pressure on the low pressure side.

As a result, there was a problem in that the durability of the suction valve of the refrigerant compressor 3 deteriorated. If the intermittent operation cycle of the refrigerant compressor 3 based on the suction air temperature of the indoor heat exchanger 6 is short, this becomes a particular problem because the refrigerant compressor 3 is restarted before the low-pressure side pressure is sufficiently lowered.

Moreover, if the refrigerant replenishment work is performed immediately after the refrigerant compressor 3 is stopped, the refrigerant replenishment can will be adversely affected.

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

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a refrigerant compressor that compresses and discharges sucked refrigerant, and a refrigerant compressor that is provided with a refrigerant compressor that controls engine rotation when energized. an electromagnetic clutch that transmits the transmission 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 an indoor heat exchanger that is connected upstream of the refrigerant compressor. , an outdoor heat exchanger that exchanges heat between the supplied refrigerant and the hydraulic oil of the hydraulic equipment, and a refrigerant passage that connects the indoor heat exchanger and the outdoor heat exchanger, and is provided upstream of the outdoor heat exchanger. a pressure reducing device provided upstream of the pressure reducing device, an electromagnetic valve that opens and closes the refrigerant passage, and a control circuit that controls energization of the electromagnetic clutch and the electromagnetic valve; With the stop of power supply to the electromagnetic clutch,
The technical means is to control the energization of the solenoid valve so as to shut off the refrigerant passage.

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

As a result, even if the refrigerant compressor stops due to de-energization of the electromagnetic clutch, the solenoid valve installed upstream of the pressure reducing device blocks the refrigerant passage, so the outdoor heat exchanger located downstream of the pressure reducing device The refrigerant does not flow in. As a result, it is possible to prevent a sudden increase in the pressure on the low pressure side after the refrigerant compressor is stopped, and it is possible to suppress a decrease in the durability of the suction valve of the refrigerant compressor.

[Example 2] Next, a vehicle air conditioner according to the present invention will be described based on an example shown in the drawings.

FIG. 1 shows a refrigeration cycle of a vehicle air conditioner.

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

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

On the downstream side of the refrigerant compressor 3, there is a high temperature gas discharged from the refrigerant compressor 3 after being blown by the condenser fan 4 during cooling operation.
A refrigerant condenser 5 is provided to condense and liquefy high-pressure refrigerant.

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

A cooling pressure reducing device 7 and a solenoid valve 9 for opening and opening a bypass passage 8 that bypasses the cooling pressure reducing device 7 are disposed downstream of the refrigerant condenser 5.

The cooling pressure reducing device 7 and the electromagnetic valve 9 are used to exchange heat between the refrigerant depressurized by the cooling pressure reducing device 7 and the surrounding air during cooling operation, and to allow the electromagnetic valve 9 to exchange heat with the surrounding air during heating operation. An indoor heat exchanger 6 is provided for exchanging heat between the high-temperature, high-pressure gaseous refrigerant passed therethrough and the surrounding air. During the cooling operation and the heating operation, the air that has undergone heat exchange with the refrigerant in the indoor heat exchanger 6 is blown into the vehicle interior as cold air and warm air by the operation of the indoor fan 10.

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

Further, in the heating passage 12, a heating pressure reducing device 15 is disposed downstream of the solenoid valve 14, and further downstream of the heating pressure reducing device 15, a refrigerant that has been depressurized by the heating pressure reducing device 15, An outdoor heat exchanger 16 is provided to exchange heat with hydraulic oil of hydraulic equipment (not shown) mounted on the vehicle.

The outdoor heat exchanger 16 is connected via an oil passage 17 to an oil tank (not shown) that stores hydraulic oil for hydraulic equipment, and is connected to an oil temperature raising device (not shown) provided in the oil passage 17. ) is supplied with heated hydraulic oil.

A liquid receiver 18 for storing liquid refrigerant and causing the refrigerant compressor 3 to suck gas refrigerant is disposed between the confluence of the cooling passage 11 and the heating passage 12 and the refrigerant compressor 3. There is.

This refrigeration cycle 1 is provided with pressure switches 19 and 20 downstream of the refrigerant condenser 5 and downstream of the solenoid valve 9 disposed in the bypass path 8, respectively.

During cooling operation, the pressure switch 19 is turned off to cut off power to the electromagnetic clutch 2 when the high pressure in the cycle, that is, the condensation pressure of the refrigerant rises above a set value.

The pressure switch 20 is turned on when the pressure of the indoor heat exchanger 6 rises to a predetermined value or more during heating operation, thereby energizing the condenser fan 41 via the control circuit 21.

In addition, the indoor heat exchanger 6 is connected to the ventilation path of the indoor heat exchanger 6.
A cooling thermistor 22 that detects the temperature of the air blown out of the room, and a heating thermistor 23 that detects the temperature of the air sucked into the indoor heat exchanger 6 are provided.

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

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

The electromagnetic clutch 2 has an operation mode switch 24 that is input to the control circuit 21 when the pressure switch 19 is in the on state.
Based on the signals from the cooling thermistor 22 and the heating thermistor 23, energization is controlled via the relay 25.

Further, during heating operation, the electromagnetic clutch 2 is energized when the intake air temperature detected by the heating thermistor 23 is below the set temperature, and is de-energized when the temperature exceeds the set temperature.

The solenoid valve 14 that opens and closes the heating passage 12 is activated by the relay 25 when the operation mode switch 24 is set to the heating mode.
Electricity is applied via the relay 26 only when the contact is in the on state. Therefore, even if the heating mode is selected, if the intake air temperature detected by the heating thermistor 23 exceeds the set temperature or the pressure switch 19 is turned off, and the energization to the electromagnetic clutch 2 is stopped. In this case, the energization of the solenoid valve 14 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 that controls the energization of the electromagnetic clutch 2 and the electromagnetic valve 14 will be explained based on 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 in step S1 is NO, the mode is cooling mode or OFF mode. In the case of cooling mode, the program for cooling operation is executed. In the OFF mode, the electromagnetic clutch 2 and the electromagnetic valve 14 are not energized.

If the determination result in step S1 is Y[S, step S
In 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 step S3.

In step S3, it is determined whether the temperature detected by the heating thermistor 23 is lower than or equal to the set temperature.

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

If the judgment result in step S3 is YES, step S
Return to step 1 and repeat the above program.

Next, the operation of this embodiment will be explained.

A> When cooling operation mode is selected.

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

The high temperature and high pressure gas refrigerant discharged from the refrigerant compressor 3 is
The refrigerant is condensed and liquefied in the refrigerant condenser 5 by the air blown by the condenser fan 4, subjected to reduced-pressure engraving in the air-conditioning decompression device 7, and then supplied to the indoor heat exchanger 6.

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

b) When 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. the result,
The bypass passage 8 and the heating passage 12 are opened together with 4,
The cooling passage 11 is shut off by the solenoid valve 13.

During heating operation, the pressure switch 20 is in the OFF state, so that the condenser fan 4 is de-energized.

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

The refrigerant condensed and liquefied in the indoor heat exchanger 6 by the air blown by the indoor fan 10 is subjected to reduced pressure engraving in the heating pressure reducing device 15 and then supplied to the outdoor heat exchanger 16 . Then, in the outdoor heat exchanger 16 , it exchanges heat with the heated hydraulic oil, evaporates, and is sucked into the refrigerant compressor 3 via the liquid receiver 18 .

During this heating operation, the operation mode switch 24 is turned to
When set to FF mode, if the temperature detected by the heating thermistor 23 is higher than the set temperature, or if the pressure switch 1
When 9 is turned on, the energization to the electromagnetic clutch 2 is stopped, and the energization to the electromagnetic valve 14 is also stopped.

As a result, even if the refrigerant compressor 3 stops operating, the solenoid valve 1
4 is closed, it is possible to prevent the refrigerant from flowing into the outdoor heat exchanger 16 and prevent the refrigerant from suddenly engraving in the outdoor heat exchanger 16. Therefore, as shown in FIG. 4 (relationship between hydraulic oil temperature and low pressure maximum after refrigerant compression 813 is stopped), the increase in low pressure side pressure is alleviated compared to the conventional case, so that the refrigerant compressor 3 Deterioration in the durability of the suction valve can be suppressed. Furthermore, even when the refrigerant replenishment work is performed immediately after the refrigerant compressor 3 is stopped, there is no adverse effect on the refrigerant replenishment can.

[Brief explanation of drawings]

Figure 1 shows the refrigeration cycle of the vehicle air conditioner, Figure 2 is the electrical circuit diagram of this embodiment, Figure 3 is a flowchart showing the operation of the control circuit, and Figure 4 is the maximum value of low pressure side pressure with respect to oil temperature. This is a graph showing. In the figure 2... Electromagnetic clutch 3... Refrigerant compressor 6... Indoor heat exchanger 14... Solenoid valve 16... Outdoor heat exchanger 15... Heating pressure reducing device 21... Control circuit

Claims (1)

[Scope of Claims] 1) (a) A refrigerant compressor that compresses and discharges sucked refrigerant; (b) This refrigerant compressor is equipped with a refrigerant compressor that transmits engine rotation to the refrigerant compressor when energized. (c) an indoor heat exchanger connected downstream of the refrigerant compressor to exchange heat between the supplied refrigerant and surrounding air; (d) connected upstream of the refrigerant compressor; , an outdoor heat exchanger that exchanges heat between the supplied refrigerant and the hydraulic oil of the hydraulic equipment; (e) a refrigerant passage connecting the indoor heat exchanger and the outdoor heat exchanger, a pressure reducing device provided upstream; (f) a solenoid valve provided upstream of the pressure reducing device for opening and closing the refrigerant passage; and (g) a control circuit controlling energization of the electromagnetic clutch and the electromagnetic valve. An air conditioner for a vehicle, wherein the control circuit controls the energization of the solenoid valve so as to shut off the refrigerant passage when the energization of the electromagnetic clutch is stopped.