Vehicle air conditioning unit

Abstract

Vehicle air conditioning unit with: a compressor (21) configured to compress and discharge a refrigerant; a radiator (15) configured to emit heat from the refrigerant; a heat exchanger (14) configured to absorb the heat in the refrigerant; an external heat exchanger (22) configured to release heat from the refrigerant or to absorb heat in the refrigerant; a first expansion valve (24) configured to expand the refrigerant flowing into the external heat exchanger (22); a second expansion valve (28) configured to expand the refrigerant flowing into the heat exchanger (14); a collector (30) configured to separate the refrigerant into a gas and a liquid and to allow the refrigerant to be drawn into the compressor (21), wherein the collector is provided in a refrigerant flow channel to a suction side of the compressor (21) into which the refrigerant is drawn; a heating refrigerant circuit (20a-20b-20c-20d-20e) configured to allow the refrigerant discharged by the compressor (21) to flow into the radiator (15) and release heat in the radiator (15), to allow the refrigerant flowing through the radiator (15) to flow into the outdoor heat exchanger (22) through the first expansion valve (24) and absorb the heat in the outdoor heat exchanger (22), and to allow the refrigerant flowing through the outdoor heat exchanger (22) to be drawn into the compressor (21) through the manifold; a heating and dehumidifying refrigerant circuit (20a-20b-20c-20e, 20a-20b-20f-20g-20h-20i-20e) configured to allow the refrigerant discharged by the compressor (21) to flow into the radiator (15) and release heat in the radiator (15), to allow a portion of the refrigerant that has flowed through the radiator (15) to flow into the outdoor heat exchanger (22) through the first expansion valve (24) and absorb heat in the outdoor heat exchanger (22), to allow the remaining refrigerant that has flowed through the radiator (15) to flow into the heat exchanger (14) through the second expansion valve (28) and absorb heat in the heat exchanger (14), and to allow the refrigerant that has flowed through the The air has flowed through the external heat exchanger (22) and the heat exchanger (14), and is drawn into the compressor (21) through the collector; a third expansion valve (25) configured to expand the refrigerant flowing from the radiator (15) into the heating refrigerant circuit and the heating and dehumidifying refrigerant circuit; a gas / liquid separator (29) configured to separate the refrigerant expanded through the third expansion valve (25) into a gaseous refrigerant and a liquid refrigerant; and a bypass circuit (20k) configured to allow at least some of the gaseous refrigerant separated in the gas / liquid separator to flow into a section of the compressor (21) through which the compressed refrigerant flows; and a fourth expansion valve (31) configured to expand the refrigerant flowing through the bypass circuit; and a valve opening control device configured to control the opening of the third expansion valve (25) such that the degree of subcooling of the refrigerant in the radiator (15) becomes a predetermined value, and to control the opening of the fourth expansion valve (31) such that the quantity of refrigerant flowing through the bypass circuit becomes a predetermined value.

Description

TECHNICAL AREA

[0001] The present invention relates to a vehicle air conditioning unit, which is applicable, for example, to electric vehicles. STATE OF THE ART

[0002] DE 696 29 881 T2 discloses an air conditioning unit that uses a heat pump system in which a refrigerant evaporator and a heating condenser are arranged within the unit. A compressor is equipped with a gas injection port, a fixed throttle for reducing the pressure of the refrigerant on the high-pressure side to an intermediate pressure during a cooling cycle, and a gas-liquid separator for separating the medium-pressure refrigerant, the pressure of which is reduced by the fixed throttle. The gaseous refrigerant separated by the gas-liquid separator is introduced into the gas injection port.In heating mode, the refrigerant circulates through the compressor, the condenser, the fixed throttle, the gas-liquid separator, an expansion valve, an external heat exchanger and the compressor as a closed circuit, while the gaseous refrigerant separated by the gas-liquid separator is introduced into the compressor through the gas injection port.

[0003] DE 10 2012 206 358 A1 discloses a heat pump circuit comprising: a compressor with an intake duct and an exhaust duct, a heating heat exchanger that heats air, a gas-liquid separator, and a cooling heat exchanger that cools air, in an airflow direction upstream of the heating heat exchanger. The heat pump circuit further comprises an intermediate pressure passage that directs a gas refrigerant from the gas-liquid separator to the intake duct. A variable opening / closing section opens the intermediate pressure passage and decompresses the gas refrigerant in the intermediate pressure passage, so that the gas refrigerant is introduced into the intake duct when a bypass dehumidification / heating mode is selected, in which the temperature of the air heated in the heating heat exchanger becomes equal to or higher than that of the air in the target air-conditioning room.

[0004] A conventional vehicle air conditioning unit is known to have the following: a compressor that compresses a refrigerant and discharges the compressed refrigerant; a radiator that releases heat from the refrigerant; a heat exchanger that absorbs the heat into the refrigerant; and an external heat exchanger that releases the heat from the refrigerant or absorbs the heat into the refrigerant (see, for example, JP 2000 - 25 446 A).

[0005] This vehicle air conditioning unit performs a heating operation with the following steps: allowing the refrigerant expelled from the compressor to flow into the radiator and release the heat in the radiator; allowing the refrigerant flowing through the radiator to flow into the outdoor heat exchanger through a first expansion valve and absorb the heat in the outdoor heat exchanger; and allowing the refrigerant that has flowed through the outdoor heat exchanger to be drawn into the compressor.

[0006] The vehicle air conditioning unit can perform a heating and dehumidifying operation by the following steps: allowing the refrigerant expelled from the compressor to flow into the radiator and release the heat in the radiator; allowing some of the refrigerant that has flowed through the radiator to flow into the outdoor heat exchanger through the first expansion valve and absorb the heat in the outdoor heat exchanger; allowing the remaining refrigerant to flow into the heat exchanger through a second expansion valve and absorb the heat in the heat exchanger; and allowing the refrigerant that has flowed through the outdoor heat exchanger and the heat exchanger to be drawn into the compressor. SUMMARY OF THE INVENTIONAL PROBLEM

[0007] When the vehicle air conditioning unit described above operates in heating mode or heating and dehumidifying mode when the outside air temperature is low, it is difficult for the refrigerant flowing through the outdoor heat exchanger to absorb heat from the outside air. Therefore, the amount of heat absorbed by the refrigerant in the outdoor heat exchanger is likely to be insufficient. If, in addition, the compressor of the vehicle air conditioning unit is operating while the amount of heat absorbed by the refrigerant in the outdoor heat exchanger is insufficient, the amount of refrigerant circulating in the refrigerant circuit is reduced, and therefore the amount of heat released from the refrigerant into the heater is reduced. This makes it more difficult to achieve the desired heating function.

[0008] It is therefore an object of the present invention to provide a vehicle air conditioning unit that can prevent a reduction in the amount of refrigerant discharged from the compressor when the outside air temperature is low in order to achieve a desired heating function during a heating operation, and that can also dehumidify the vehicle interior without impairing the heating function during a heating and dehumidifying operation. SOLUTION TO THE PROBLEM

[0009] The problem described above is solved by the vehicle air conditioning unit according to claim 1.

[0010] This allows at least some of the gaseous refrigerant, which is separated by the gas / liquid separator, to flow into the compressor area through which the compressed refrigerant flows. Consequently, it is possible to increase the amount of refrigerant discharged from the compressor and therefore increase the amount of heat transferred from the refrigerant to the radiator. IMPACT OF THE INVENTION

[0011] The present invention makes it possible to increase the amount of heat released from the refrigerant in the heater by increasing the amount of refrigerant discharged from the compressor. Consequently, it is possible to improve the heating function during heating operation, and it is also possible to dehumidify the vehicle interior without compromising the heating function during heating and dehumidifying operation. Furthermore, during heating operation and during heating and dehumidifying operation, the refrigerant is drawn into the compressor through the receiver, thus preventing the amount of lubricating oil returning to the compressor from becoming insufficient even if the amount of circulating refrigerant is reduced. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 shows a schematic view of a vehicle air conditioning unit according to an exemplary embodiment 1; Fig. Figure 2 shows a schematic view of the vehicle air conditioning unit, which performs a cooling operation and a cooling and dehumidifying operation; Fig. Figure 3 shows a schematic view of the vehicle air conditioning unit performing a heating operation; Fig. Figure 4 shows a schematic view of the vehicle air conditioning unit performing an initial heating and dehumidification operation; Fig. Figure 5 shows a schematic view of the vehicle air conditioning unit, which performs a second heating and dehumidifying operation; Fig. Figure 6 shows a schematic view of the vehicle air conditioning unit with a fourth solenoid valve that opens during heating operation; Fig. Figure 7 shows a schematic view of the vehicle air conditioning unit according to embodiment 2 of the present invention; Fig. Figure 8 shows a schematic view of the vehicle air conditioning unit according to embodiment 3 of the present invention; Fig. Figure 9 shows a schematic view of the vehicle air conditioning unit with an electric heating device provided in a different position; Fig. Figure 10 shows a schematic view of the vehicle air conditioning unit according to embodiment 4 of the present invention; Fig. Figure 11 shows a schematic view of the vehicle air conditioning unit according to embodiment 5 of the present invention; and Fig. Figure 12 shows a schematic view of the vehicle air conditioning unit with the fourth solenoid valve, which is opened during heating operation. DESCRIPTION OF THE EXAMPLES OF EXECUTION

[0012] The Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5 to Fig. Figure 6 shows schematic views of the vehicle air conditioning unit according to embodiment 1.

[0013] As this is shown in the Fig. As shown in Figure 1, the vehicle air conditioning unit according to embodiment 1 has an air conditioning unit 10 which is provided in the interior of the vehicle and a refrigerant circuit 20 which is formed along the interior and exterior of the vehicle.

[0014] The air conditioning unit 10 has an airflow duct 11 that allows air supplied to the vehicle interior to flow through it. An outside air inlet 11a and an inside air inlet 11b are provided at the first end of the airflow duct 11. The outside air inlet 11a is configured to allow outside air to flow into the airflow duct 11, and the inside air inlet 11b is configured to allow inside air to flow into the airflow duct 11. Meanwhile, a footwell outlet 11c, a ventilation outlet 11d, and a defroster outlet 11e are provided at the second end of the airflow duct 11. The footwell outlet 11c is configured to allow the air flowing through the airflow duct 11 to ventilate the feet of the passenger in the vehicle.The ventilation outlet 11d is configured to allow the air flowing through the airflow duct 11 to ventilate the upper bodies of the passengers in the vehicle. The defroster outlet 11e is configured to allow the air flowing through the airflow duct 11 to ventilate the inner surface of the windshield.

[0015] An internal fan 12, such as a Sirokko fan, configured to allow air to flow through the airflow channel 11 from one end to the other, is provided at the first end of the airflow channel 11.

[0016] Furthermore, an inlet damper 13 is configured at the first end of the airflow duct 11 to open either the outside air inlet 11a or the inside air inlet 11b and close the other. When the inlet damper 13 closes the inside air inlet 11b and opens the outside air inlet 11a, the mode switches to an outside air supply mode, in which air flows from the outside air inlet 11a to the airflow duct 11. Conversely, when the inlet damper 13 closes the outside air inlet 11a and opens the inside air inlet 11b, the mode switches to an inside air recirculation mode, in which air flows from the inside air inlet 11b into the airflow duct 11.Furthermore, if the inlet switching flap 13 is placed between the outside air inlet 11a and the inside air inlet 11b and the outside air inlet 11a and the inside air inlet 11b are open, the mode is switched to a two-way mode in which the air flows into the airflow duct 11 from both the outside air inlet 11a and the inside air inlet 11b according to the opening ratio of the outside air inlet 11a and the inside air inlet 11b.

[0017] Outlet flaps 13b, 13c, and 13d, configured to open and close the footwell outlet 11c, the ventilation outlet 11d, and the defroster outlet 11e, are located on the second side of the airflow duct 11 at the footwell outlet 11c, the ventilation outlet 11d, and the defroster outlet 11e, respectively. These outlet flaps 13b, 13c, and 13d are configured to move together via a coupling (not shown). When the outlet flaps 13b, 13c, and 13d open the footwell outlet 11c, close the ventilation outlet 11d, and slightly open the defroster outlet 11e, most of the air flowing through the airflow duct 11 is blown out of the footwell outlet 11c, and the remaining air is blown out of the defroster outlet 11e. This mode is referred to as a "footwell mode".If, meanwhile, the outlet flaps 13b, 13c, and 13d close the footwell outlet 11c and the defroster outlet 11e and open the ventilation outlet 11d, all the air flowing through the airflow duct 11 is blown out of the ventilation outlet 11d. This mode is referred to as a "ventilation mode." If, in addition, the outlet flaps 13b, 13c, and 13d open the footwell outlet 11c and the ventilation outlet 11d and close the defroster outlet 11e, the air flowing through the airflow duct 11 is blown out of the footwell outlet 11c and the ventilation outlet 11d. This mode is referred to as a "bi-level mode." Furthermore, if the outlet flaps 13b, 13c and 13d close the footwell outlet 11c and the ventilation outlet 11d and open the defroster outlet 11e, the air flowing through the airflow duct 11 is blown out of the defroster outlet 11e. This mode is referred to as a "defroster mode".Furthermore, if the outlet flaps 13b, 13c, and 13d close the ventilation outlet 11d and open the footwell outlet 11c and the defroster outlet 11e, the air flowing through the airflow duct 11 is blown out of the footwell outlet 11c and the defroster outlet 11e. This mode is referred to as a "defroster / footwell mode." In this bi-level mode, the airflow duct 11, the footwell outlet 11c, the ventilation outlet 11d, and a heat exchanger and a radiator, which will be described later, are arranged and configured such that the temperature of the air blown out of the footwell outlet 11c is higher than the temperature of the air blown out of the ventilation outlet 11d.

[0018] A heat exchanger 14 is provided in the airflow duct 11 downstream of the airflow from the internal fan 12. The heat exchanger 14 is configured to cool and dehumidify the air flowing through the airflow duct 11. Additionally, a radiator 15 is provided in the airflow duct 11 downstream of the air flowing from the heat exchanger 14. The radiator 15 is configured to heat the air flowing through the airflow duct 11. The heat exchanger 14 and the radiator 15 are heat exchangers, each formed by fins and tubes, and configured to perform a heat exchange between the refrigerant flowing through them and the air flowing through the airflow duct 11.

[0019] An air mixing damper 16 is provided between the heat exchanger 14 and the radiator 15 in the airflow duct 11 and is configured to control the proportion of air to be heated that flows through the airflow duct 11. When the air mixing damper 16 is moved from the upstream side of the airflow duct 11 to close the radiator 15, the proportion of air exposed to heat exchange in the radiator 15 is reduced. Conversely, when the air mixing damper 16 is moved to a position different from the radiator 15 in the airflow duct 11, the proportion of air exposed to heat exchange is increased.If, in the airflow duct 11, the air mixing flap 16 closes the upstream side of the radiator 15 and opens the section outside the radiator 15, the opening is 0%, and if, on the other hand, the air mixing flap 16 opens the upstream side of the radiator 15 and closes the section outside the radiator 15, the opening is 100%.

[0020] The refrigerant circuit 20 comprises the following: the heat exchanger 14; the radiator 15; a compressor 21 configured to compress a refrigerant; an outdoor heat exchanger 22 configured to perform heat exchange between the refrigerant and the outside air; an indoor heat exchanger 23 configured to perform heat exchange between the refrigerant discharged from the radiator 15 and the outdoor heat exchanger 22, or at least from the radiator 15, and the refrigerant discharged from the heat exchanger 14; a control valve 24 comprising an expansion section as a first expansion valve and a condensation pressure regulating section, and capable of switching the refrigerant flow channel of the control valve 24 between the expansion section side and the condensation pressure regulating section side;An expansion valve 25 for refrigerant with heat release as a third expansion valve to expand the refrigerant discharged from the radiator 15; a first to fourth solenoid valve 26a, 26b, 26c and 26d (26a to 26d); a first and a second check valve 27a and 27b; a heat exchanger expansion valve 28 as a second expansion valve for expanding the refrigerant flowing into the heat exchanger 14; a gas / liquid separator 29 that separates the refrigerant expanded through the expansion part 25 for refrigerant with heat release into a gas and a liquid; and a receiver 30 that separates the gaseous refrigerant from the liquid refrigerant and allows the gaseous refrigerant to be drawn into the compressor 21. These components are connected to each other by a copper or aluminum tube.

[0021] More precisely, the inlet side of the radiator 15, into which the refrigerant flows, is connected to the delivery side of the compressor 21, from which the refrigerant is discharged, thus forming a refrigerant flow channel 20a. Additionally, the inlet side of the first control valve 24, into which the refrigerant flows, is connected to the outlet side of the radiator 15, from which the refrigerant is discharged, thus forming a refrigerant flow channel 20b. Within the refrigerant flow channel 20b, the expansion valve 25 for refrigerant with heat transfer and the gas / liquid separator 29 are located, in order from the upstream side of the refrigerant flow direction. The first end of the external heat exchanger 22 is connected to the outside of the control valve 24, from which the refrigerant is discharged, thus forming a refrigerant flow channel 20c. A first check valve 27a is provided in the refrigerant flow channel 20c.Additionally, the second end of the external heat exchanger 22 is connected to the discharge side of the condensing pressure regulating section of the control valve 24, from which the refrigerant is discharged, thus forming a refrigerant flow channel 20d. The suction side of the compressor 21, into which the refrigerant is drawn, is connected to the second end of the external heat exchanger 22 in parallel to the refrigerant flow channel 20d, thus forming a refrigerant flow channel 20e. A first solenoid valve 26a and the receiver 30 are provided in the refrigerant flow channel 20e, in sequence from the upstream side of the refrigerant flow direction. The inlet side of the internal heat exchanger 23, into which the refrigerant flows at high pressure, is connected to the refrigerant flow channel 20b, thus forming a refrigerant flow channel 20f. A second solenoid valve 26b is provided in the refrigerant flow channel 20f.The inlet side of heat exchanger 14, through which the refrigerant flows, is connected to the outlet side of internal heat exchanger 23, from which the refrigerant is discharged at high pressure, thus forming a refrigerant flow channel 20g. The heat exchanger expansion valve 28 is located in refrigerant flow channel 20g. The inlet side of internal heat exchanger 23, through which the refrigerant flows at low pressure, is connected to the outlet side of heat exchanger 14, from which the refrigerant is discharged, thus forming a refrigerant flow channel 20h. The section of refrigerant flow channel 20e between the first solenoid valve 26a and the receiver 30 is connected to the outlet side of internal heat exchanger 23, from which the refrigerant is discharged at low pressure, thus forming a refrigerant flow channel 20i.The refrigerant flow channel 20f downstream of the second solenoid valve 26b in the refrigerant flow direction is connected to the first end of the external heat exchanger 22 in parallel with the refrigerant flow channel 20c, forming a refrigerant flow channel 20j. A third solenoid valve 26c and a second check valve 27b are provided in the refrigerant flow channel 20j, in sequence from the upstream side of the refrigerant flow direction. The suction side of the compressor 21, into which the refrigerant is drawn, is connected to the gas / liquid separator 29, forming a bypass circuit in the refrigerant flow channel 20k. A fourth solenoid valve 26d is provided in the refrigerant flow channel 20k.

[0022] The compressor 21 and the external heat exchanger 22 are located in an engine compartment outside the vehicle interior.

[0023] Compressor 21 has a refrigerant suction port, to which refrigerant flow channel 20e is connected, and a refrigerant inlet, to which refrigerant flow channel 20k is connected. The refrigerant inlet is connected to the area of ​​compressor 21 through which the compressed refrigerant flows. Compressor 21 is driven by an electric motor and rotates at a speed that can be controlled by an inverter.

[0024] The external heat exchanger 22 is a heat exchanger formed by fins and tubes and configured to perform heat exchange between the refrigerant flowing through the external heat exchanger 22 and the air outside the vehicle interior. When the external heat exchanger 22 operates as a heat exchanger, the refrigerant flows into the external heat exchanger 22 from the first end of the refrigerant flow channel of the external heat exchanger 22. When the external heat exchanger 22 operates as a radiator, the refrigerant flows into the external heat exchanger 22 from the second end of the refrigerant flow channel of the external heat exchanger 22. A gas / liquid separator 22a and a subcooling section 22b are provided at the first end of the refrigerant flow channel of the external heat exchanger 22. The gas / liquid separator 22a can collect liquid refrigerant when the external heat exchanger 22 operates as a radiator.The subcooling section 22b subcools the liquid refrigerant flowing from the gas / liquid separator 22a. Additionally, the external heat exchanger 22 has an external fan 22c that performs heat exchange between the air outside the vehicle interior and the refrigerant while the vehicle is stationary.

[0025] The internal heat exchanger 23, for example, is a double-pipe heat exchanger or a stack heat exchanger, and it is configured to perform heat exchange between the refrigerants themselves.

[0026] The expansion section of the control valve 24 expands the refrigerant flowing into the outdoor heat exchanger 22 during heating operation and during the initial heating and dehumidification operation. Meanwhile, the condensation control section of the control valve 24 regulates the condensation pressure of the refrigerant in the radiator 15 during cooling and dehumidification operation. The control valve 24 has a stepper motor that switches the refrigerant flow passage of the control valve 24 between the expansion section and the condensation pressure control section, and it controls the opening of the corresponding refrigerant flow passage to the expansion section and the refrigerant flow passage to the condensation pressure control section.

[0027] The heat exchanger expansion valve 28 is a temperature expansion valve with an adjustable opening according to the temperature of the refrigerant flowing from the heat exchanger 14. A temperature expansion valve can, for example, be a box-type temperature valve including a refrigerant outlet passage that allows the refrigerant to flow out of the heat exchanger, a temperature-sensitive rod that detects the temperature of the refrigerant flowing from the outlet passage, and a diaphragm that moves the valve element; these components are formed as a single piece.

[0028] The gas / liquid separator 29 collects the refrigerant, receives the refrigerant which is expanded by the refrigerant expansion valve 25 (for refrigerants with released heat), and separates the refrigerant into a gaseous refrigerant and a liquid refrigerant. The refrigerant flow channel 20b is connected to the lower part of the gas / liquid separator 29, and therefore, essentially liquid refrigerant can flow into one or both of the external heat exchanger 22 and the heat exchanger 14. Meanwhile, the refrigerant flow channel 20k is connected to the upper part of the gas / liquid separator 29, and therefore, essentially gaseous refrigerant can flow into the compressor 21, through which the compressed refrigerant flows.

[0029] The vehicle air conditioning unit with the configuration described above performs a cooling operation, a cooling and dehumidifying operation, a heating operation, a first heating and dehumidifying operation, and a second heating and dehumidifying operation. Each operation is described below.

[0030] During cooling operation and during cooling and dehumidifying operation, the refrigerant flow passage of the control valve 24 in the refrigerant circuit 20 is set as the condensing pressure regulating section; the third solenoid valve 26c is open; the first, second, and fourth solenoid valves 26a, 26b, and 26d are closed; and the compressor 21 is operated. As shown in the Fig. As shown in Figure 2, the refrigerant discharged from the compressor 21 flows through the refrigerant circuit 20 in the following sequence: the refrigerant flow channel 20a; the radiator 15; the refrigerant flow channels 20b and 20d; the external heat exchanger 22; the refrigerant flow channels 20j and 20s; the high-pressure side of the internal heat exchanger 23; the refrigerant flow channel 20g; the heat exchanger 14; the refrigerant flow channel 20h; the low-pressure side of the internal heat exchanger 23; the refrigerant flow channels 20i and 20e, and is drawn into the compressor 21. During cooling operation, the refrigerant flowing through the refrigerant circuit 20 releases heat to the outdoor heat exchanger 22 and absorbs heat in the heat exchanger 14. During cooling and dehumidifying operation, when the air mixing flap 16 is open, as indicated by the dashed line in the Fig. As shown in Figure 2, the refrigerant flowing through the refrigerant circuit 20 also releases heat into the radiator 15. The refrigerant flowing through the outdoor heat exchanger 22 is separated in the gas / liquid separator 22a into a gaseous refrigerant and a liquid refrigerant, and the liquid refrigerant is supercooled in the subcooling section 22b. Therefore, the refrigerant flowing from the outdoor heat exchanger 22 becomes a supercooled liquid. During cooling operation and during cooling and dehumidifying operation, the temperature of the refrigerant flowing from the heat exchanger 14 is set to a predetermined superheat level by controlling the opening of the heat exchanger expansion valve 28. Therefore, all the refrigerant flowing into the receiver 30 is a gaseous refrigerant, and liquid refrigerant does not remain in the receiver 30 but is drawn into the compressor 21.

[0031] In this case, the interior fan 12 of the air conditioning unit 10 is operated during cooling operation so that the air flows through the airflow duct 11, and the air is subjected to heat exchange with the refrigerant in the heat exchanger 14 and cooled. The temperature of the cooled air is then adjusted to the setpoint air blower temperature TAO of the air that is blown from the outlets 11c, 11d and 11e into the vehicle interior to set the interior temperature to the setpoint temperature Tset.

[0032] The target air blower temperature TAO is calculated based on the preset temperature Tset and ambient conditions including the outside air temperature Tam, the inside air temperature Tr and an insulation amount Ts.

[0033] During cooling and dehumidification operation, the interior fan 12 of the air conditioning unit 10 is operated so that the air flows through the airflow duct 11. The air is then subjected to heat exchange with the refrigerant, which absorbs heat in the heat exchanger 14, thus cooling and dehumidifying it. The air, dehumidified in the heat exchanger 14, is then subjected to heat exchange with the refrigerant, which transfers heat to the radiator 15, thus warming it. As a result, the air is blown into the vehicle interior at the set air blower temperature TAO.

[0034] During the heating operation, the refrigerant flow path of the control valve 24 in the refrigerant circuit 20 is set as the expansion section; the first solenoid valve 26a is open; the second, third, and fourth solenoid valves 26b, 26c, and 26d are closed; and the compressor 21 is operated. As shown in the Fig. As shown in Figure 3, the refrigerant discharged from compressor 21 flows through the refrigerant circuit 20 in the following sequence: refrigerant flow channel 20a; radiator 15; refrigerant flow channels 20b and 20c; outdoor heat exchanger 22; refrigerant flow channels 20d and 20e, and is drawn into compressor 21. The refrigerant flowing through the refrigerant circuit 20 releases heat in the radiator 15 and absorbs heat in the outdoor heat exchanger 22. By controlling the opening of the expansion valve 25 for refrigerants with released heat, the temperature of the refrigerant flowing through the radiator 15 is set to a predetermined degree of subcooling during heating operation. The refrigerant flowing from the radiator 15 is expanded by the expansion valve 25 for refrigerants with released heat and the expansion part of the control valve 24, and it flows into the outdoor heat exchanger 22.The refrigerant flowing from the external heat exchanger 22 is separated into a gaseous refrigerant and a liquid refrigerant in the collector 30, and only the gaseous refrigerant is drawn into the compressor 21.

[0035] In this case, the interior fan 12 is operated at the air conditioning unit 10 so that the air flows through the airflow duct 11. The flowing air is not subject to heat exchange with the refrigerant in the heat exchanger 14, but it is subject to heat exchange with the refrigerant in the heater 15, and is therefore warmed. As a result, the air is blown into the vehicle interior at the set air blower temperature TAO.

[0036] During the first heating and dehumidifying operation, the refrigerant flow path of the control valve 24 in the refrigerant circuit 20 is set as the expansion section; the first and second solenoid valves 26a and 26b are open; the third and fourth solenoid valves 26c and 26d are closed; and the compressor 21 is operated. As shown in the Fig. As shown in Figure 4, the refrigerant discharged from the compressor 21 flows through the refrigerant circuit 20 in the following sequence: the refrigerant flow channel 20a; the radiator 15; and the refrigerant flow channel 20b. A portion of the refrigerant that has flowed through the refrigerant flow channel 20b flows through the refrigerant circuit 20 in the following sequence: the refrigerant flow channel 20c; the outdoor heat exchanger 22; and the refrigerant flow channel 20e, and it is drawn into the compressor 21.Meanwhile, the remaining refrigerant, which has flowed through refrigerant flow channel 20b, flows through refrigerant circuit 20 in the following sequence: refrigerant flow channel 20f; the high-pressure side of the internal heat exchanger 23; refrigerant flow channel 20g; heat exchanger 14; refrigerant flow channel 20h; the low-pressure side of the internal heat exchanger 23; refrigerant flow channels 20i and 20e, and is drawn into the compressor 21. The refrigerant flowing through refrigerant circuit 20 releases heat in the radiator 15 and absorbs heat in the heat exchanger 14 and the external heat exchanger 22. During the first heating and dehumidifying operation, the temperature of the refrigerant flowing through the radiator 15 is adjusted to a predetermined degree of subcooling by controlling the opening of the refrigerant expansion valve 25 with heat release.Then, a portion of the refrigerant flowing from the radiator 15 is expanded through the expansion valve 25 for refrigerant with heat release and the expansion section of the control valve 24. Meanwhile, the remaining refrigerant is expanded through the expansion valve 25 for refrigerant with heat release and the heat exchanger expansion valve 28 and flows into the heat exchanger 14. The refrigerant flowing from the heat exchanger 14 and the outdoor heat exchanger 22 is separated into a liquid refrigerant and a gaseous refrigerant in the receiver 30, and only the gaseous refrigerant is drawn into the compressor 21.

[0037] In this case, the interior fan 12 is operated at the air conditioning unit 10 so that the air flows through the airflow duct 11. The flowing air is subjected to heat exchange with the refrigerant in the heat exchanger 14, and is therefore cooled and dehumidified. At least some of the air that has been dehumidified in the heat exchanger 14 is subjected to heat exchange with the refrigerant in the heater 15 and is heated. As a result, the air is blown into the vehicle interior at the set air blower temperature TAO.

[0038] During the second heating and dehumidification operation, the refrigerant flow passage of the control valve 24 in the refrigerant circuit 20 is closed; the second solenoid valve 26b is open; the first, third, and fourth solenoid valves 26a, 26c, and 26d are closed; and the compressor 21 is operating. As shown in the Fig. As shown in Figure 5, the refrigerant discharged from the compressor 21 flows through the refrigerant circuit 20 in the following sequence: the refrigerant flow channel 20a; the radiator 15; the refrigerant flow channels 20b and 20f; the high-pressure side of the internal heat exchanger 23; the refrigerant flow channels 20g; the heat exchanger 14; the refrigerant flow channel 20h; the low-pressure side of the internal heat exchanger 23; and the refrigerant flow channels 20i and 20e, and is drawn into the compressor 21. The refrigerant flowing through the refrigerant circuit 20 releases heat in the radiator 15 and absorbs heat in the heat exchanger 14. During the second heating and dehumidification operation, the temperature of the refrigerant flowing through the heat exchanger 15 is set to a predetermined degree of subcooling by controlling the opening of the expansion valve 25 for refrigerants with released heat.Additionally, the refrigerant flowing from the radiator 15 is expanded through the expansion valve 25 for refrigerants with released heat and the heat exchanger expansion valve 28, and it flows into the heat exchanger 14. The refrigerant flowing from the heat exchanger 14 is separated into a liquid refrigerant and a gaseous refrigerant in the collector 30, and only the gaseous refrigerant is drawn into the compressor 21.

[0039] In this case, the indoor fan 12 is operated at the air conditioning unit 10 so that the air flows through the airflow duct 11, and the flowing air is subjected to heat exchange with the refrigerant in the heat exchanger 14, and therefore it is cooled and dehumidified in the same way as in the first heating and dehumidification operation. A portion of the air dehumidified in the heat exchanger 14 is subjected to heat exchange with the refrigerant in the radiator 15, and therefore it is heated.

[0040] As a result, air at the target air blower temperature TAO is blown into the vehicle interior.

[0041] While an automatic switch is turned on, the operation is switched between cooling operation, cooling and dehumidifying operation, heating operation, the first heating and dehumidifying operation and the second heating and dehumidifying operation based on ambient conditions including the outside air temperature Tam, the inside air temperature Tr, the outside air humidity, the inside air humidity Th, the insulation value Ts and the like.

[0042] Additionally, the operating mode of outlets 11c, 11d, and 11e is controlled by the outlet switching flaps 13b, 13c, and 13d. The opening of the air mixing flap 16 is controlled so that the temperature of the air blown from outlets 11c, 11d, and 11e reaches the target air blower temperature TAO.

[0043] During each operation, the operating mode is switched between footwell mode, ventilation mode, and bi-level mode according to the setpoint air blower temperature (TAO). Specifically, the mode is set to footwell mode when the setpoint air blower temperature (TAO) is high, for example, 40°C. If, at the same time, the setpoint air blower temperature (TAO) is low, for example, less than 25°C, the mode is set to ventilation mode. Furthermore, if the setpoint air blower temperature (TAO) is a temperature between the temperature for footwell mode and the temperature for ventilation mode, the mode is set to bi-level mode.

[0044] If the outside air temperature is low during heating operation or the initial heating and dehumidification cycle, it is difficult for the refrigerant flowing through the outdoor heat exchanger 22 to absorb heat. During heating operation or the initial heating and dehumidification cycle, the amount of refrigerant circulating in the refrigerant circuit 20 is reduced if the amount of heat absorbed by the refrigerant in the outdoor heat exchanger 22 is insufficient. Consequently, the amount of heat released from the refrigerant into the radiator 15 is reduced. As a result, the heating function may be impaired.

[0045] Therefore, if the outside air temperature is low during heating operation or the first heating and dehumidifying operation, the fourth solenoid valve 26d is opened to increase the amount of heat released from the refrigerant in the radiator 15.

[0046] If the fourth solenoid valve 26d is opened during the heating cycle or the first heating and dehumidifying operation, as described in the Fig. As shown in Figure 6 (which depicts the heating operation), a portion of the refrigerant flowing into the gas / liquid separator 29 passes through the refrigerant flow channel 2k and then flows into the compressor 21, through which the compressed refrigerant flows. In this case, the refrigerant flowing into the compressor 21 is essentially gaseous refrigerant that has flowed out of the upper part of the gas / liquid separator 29. However, depending on the operating conditions, a two-phase refrigerant with gaseous and liquid phases is likely to flow into the compressor 21. Additionally, the amount of refrigerant flowing into the compressor 21 through the refrigerant flow channel 20k is set to a predetermined value by controlling the opening of the expansion section of the control valve 24.

[0047] This results in essentially gaseous refrigerant flowing into the compressor 21, through which the compressed refrigerant flows. Therefore, it is possible to increase the amount of refrigerant discharged from the compressor 21, even if the amount of heat absorbed by the refrigerant in the outdoor heat exchanger 22 is insufficient and consequently the amount of refrigerant circulating in the refrigerant circuit 20 is reduced. By increasing the amount of refrigerant discharged from the compressor 21, it is possible to increase the amount of heat released from the refrigerant in the radiator 15.

[0048] Additionally, the refrigerant is drawn into the compressor 21 through the collector 30, and therefore it is possible that the lubricating oil returns to the compressor 21, which is required to lubricate the compressor 21.

[0049] As described above in the present embodiment, the vehicle air conditioning unit comprises the following: the expansion valve 25 for refrigerant with heat release, which expands the refrigerant flowing out of the radiator 15 during the heating operation and the first heating and dehumidifying operation; the gas / liquid separator 29, which separates the refrigerant expanded by the expansion valve 25 for refrigerant with heat release into a gaseous refrigerant and a liquid refrigerant; and the refrigerant flow channel 20k as a bypass circuit, which allows at least some of the gaseous refrigerant separated in the gas / liquid separator 29 to flow into the area of ​​the compressor 21 through which the expanded refrigerant flows.If the outside air temperature is low during heating operation or the initial heating and dehumidification operation, the amount of heat released from the refrigerant in the heater 15 can be increased by increasing the amount of refrigerant discharged from the compressor 21. This improves the heating function during heating operation and also allows the vehicle interior to be dehumidified without compromising the heating function during heating and dehumidification operation. During heating operation and during heating and dehumidification operation, refrigerant is additionally drawn into the compressor 21 via the receiver 30, thus preventing an insufficient amount of lubricating oil returning to the compressor 21, even if the amount of circulating refrigerant is reduced.

[0050] During the heating operation and during the initial heating and dehumidification operation, the opening of the expansion valve 25 for refrigerant with released heat is controlled so that the degree of subcooling of the refrigerant in the heater 15 reaches a predetermined value, and the opening of the expansion section of the control valve 24 is controlled so that the amount of refrigerant flowing through the refrigerant flow channel 20k reaches a predetermined value. This ensures that the required amount of heat is released by the refrigerant in the heater 15, thus improving the control function for achieving a target temperature in the vehicle interior.

[0051] The Fig. Figure 7 shows a schematic view of the vehicle air conditioning unit according to embodiment 2 of the present invention. The components are designated with the same reference numerals as in the embodiment described above.

[0052] As this is shown in the Fig. As shown in Figure 7, this vehicle air conditioning unit has a bypass expansion valve 31, which is an electronic expansion valve with an adjustable opening, provided in the refrigerant flow channel 20k instead of the fourth solenoid valve 26d according to embodiment 1.

[0053] In the vehicle air conditioning unit with the configuration described above, the bypass expansion valve 31 is opened to increase the amount of heat released from the refrigerant in the heater 15 when the outside air temperature is low during the heating operation or the first heating and dehumidifying operation.

[0054] If the bypass expansion valve 31 is open during heating operation or the first heating and dehumidifying operation, as described in the Fig. As shown in Figure 7 (which depicts the heating operation), a portion of the refrigerant that has flowed through the gas / liquid separator 29 flows through the refrigerant flow channel 20k and into the compressor 21, through which the compressed refrigerant flows. In this case, the refrigerant flowing into the compressor 21 is essentially gaseous refrigerant that has flowed out of the upper part of the gas / liquid separator 29. However, depending on the operating conditions, a biphase refrigerant with gaseous and liquid phases is likely to flow into the compressor 21. Additionally, the amount of refrigerant flowing into the compressor 21 through the refrigerant flow channel 20k is set to a predetermined value by controlling the opening of the bypass expansion valve 31, while the opening of the expansion section of the control valve 24 is fixed.

[0055] This allows the essentially gaseous refrigerant to flow in the area of ​​the compressor 21 through which the compressed refrigerant flows. Therefore, it is possible to increase the amount of refrigerant discharged from the compressor 21, even if the amount of heat absorbed by the refrigerant in the outdoor heat exchanger 22 is insufficient, and consequently, the amount of refrigerant circulating in the refrigerant circuit 20 is reduced. By increasing the amount of refrigerant discharged from the compressor 21, it is possible to increase the amount of heat released from the refrigerant in the radiator 15.

[0056] Additionally, the refrigerant is drawn into the compressor 21 through the collector 30, and therefore it is possible that the lubricating oil returns to the compressor 21, which is required to lubricate the compressor 21.

[0057] As described above for the vehicle air conditioning unit according to the present embodiment, it is possible to increase the amount of heat released from the refrigerant in the heater 15 by increasing the amount of refrigerant discharged from the compressor 21 when the outside air temperature is low during the heating operation or the first heating and dehumidifying operation, as in the embodiment described above. Therefore, it is possible to improve the heating function during the heating operation, and it is also possible to dehumidify the vehicle interior without impairing the heating function during the heating and dehumidifying operation.Additionally, during heating operation and during heating and dehumidification operation, the refrigerant is drawn into the compressor 21 through the collector 30, and therefore it is possible to prevent an insufficient amount of lubricating oil returning to the compressor 21, even if the amount of circulating refrigerant is reduced.

[0058] During the heating operation and during the initial heating and dehumidification operation, the opening of the refrigerant expansion valve 25 is controlled to ensure that the degree of subcooling of the refrigerant in the heater 15 reaches a predetermined value. Additionally, the opening of the bypass expansion valve 31 is controlled to ensure that the amount of refrigerant flowing through the refrigerant flow channel 20k reaches a predetermined value. This ensures that the required amount of heat is released from the refrigerant in the heater 15, thereby improving the control function to achieve a target temperature for the vehicle interior.

[0059] The Fig. Figure 8 shows a schematic view of the vehicle air conditioning unit according to embodiment 3 of the present invention. The components are designated with the same reference numerals as in the embodiments described above.

[0060] As this is shown in the Fig. As shown in Figure 8, this vehicle air conditioning unit has a refrigerant radiator 33 which is provided outside the airflow duct 11 and is configured as a radiator to carry out heat exchange between water as a heating medium and the refrigerant, instead of the radiator 15 according to embodiment 1.

[0061] A water circuit 40, acting as a heating medium circuit through which water flows, is connected to a heat exchanger section 33a of the refrigerant heater 33 and is configured to perform heat exchange between the water and the refrigerant. A water pump 41, configured to discharge water; a heating core 42, acting as a heating medium heater configured to perform heat exchange between the air flowing through the airflow duct 11 and the water; an engine heater 43, acting as an exhaust heat absorption section configured to absorb the exhaust heat from the engine that propels the vehicle into the water; and an electric heating device 44, configured to heat the water, are connected to the water circuit 40.

[0062] In the vehicle air conditioning unit with the configuration described above, it is possible for the refrigerant to flow through the refrigerant circuit 20 in the same way as in embodiment 1, and it is also possible for a refrigerant with an essentially gaseous phase to flow into the compressor 21 through the refrigerant flow channel 20k in the gas / liquid separator 29.

[0063] During cooling and dehumidification operation, during heating operation, during the first heating and dehumidification operation and during the second heating and dehumidification operation, the water pump 41 is driven so that the water flows through the water circuit 40.

[0064] The water flowing through the water circuit 40 absorbs heat from the refrigerant in the refrigerant heating element 33 and, in the heating core 42, undergoes heat exchange with the air flowing through the airflow duct 11, releasing the heat. The water flowing through the water circuit 40 is heated in the refrigerant heating element 33 and is also heated by the exhaust heat from the engine in the engine heating element 43. If the heat from the air flowing through the airflow duct 11 is insufficient, the water flowing through the water circuit 40 is heated by the electric heating device 44, thus compensating for any insufficient heat.

[0065] As described above for the vehicle air conditioning unit according to the present embodiment, it is possible to increase the amount of heat released from the refrigerant in the refrigerant heater 33 by increasing the amount of refrigerant discharged from the compressor 21 when the outside air temperature is low during the heating operation or the first heating and dehumidifying operation, in the same manner as in embodiment 1. Therefore, it is possible to improve the heating function during the heating operation, and it is also possible to dehumidify the vehicle interior without impairing the heating function during the heating and dehumidifying operation.During heating operation and during heating and dehumidification operation, the refrigerant is additionally drawn into the compressor 21 through the collector 30, and therefore it is possible to prevent the amount of lubricating oil returning to the compressor 21 from becoming insufficient, even if the amount of circulating refrigerant is reduced.

[0066] Furthermore, the engine heating element 43 is connected to the water circuit 40 to heat the water flowing through the water circuit 40 by utilizing the exhaust heat from the engine. By heating the water flowing through the water circuit 40 using the exhaust heat from the engine, it is therefore possible to carry out the heating operation and the initial heating and dehumidification operation. Consequently, it is possible to reduce energy consumption by efficiently utilizing the exhaust heat from the engine.

[0067] Furthermore, the electric heating device 44 is provided for heating the water flowing through the water circuit 40. This makes it possible to compensate for any amount of heat that is insufficient to achieve the desired heating function of the heating operation and the initial heating and dehumidifying operation, and therefore to maintain the vehicle interior at a desired temperature.

[0068] In embodiment 3, a configuration was described in which the amount of heat for the heating operation and the first heating and dehumidification operation is insufficient and is compensated for by using the electric heating device 44, which heats the water flowing through the water circuit 40. However, this is not a limitation. As is the case, for example, in the Fig. As shown in Figure 9, another configuration is possible in which the electric heating device 44 is provided in the refrigerant flow channel 20f between the receiver 30 and the compressor 21 to heat the refrigerant flowing through the refrigerant circuit 20. Additionally, the position of the electric heating device 44 in the refrigerant circuit 20 is not limited to the position between the receiver 30 and the compressor 21. For example, the electric heating device 44 can be provided in the refrigerant flow channel 20k, or it can be provided in the position between the delivery side of the compressor 21 and the refrigerant heater 33. Furthermore, another configuration is possible in which the electric heating devices 44 are located in the water circuit 40 or...the refrigerant circuit 20 are provided, and the water flowing through the water circuit 40 and the refrigerant flowing through the refrigerant circuit 20 are heated by the corresponding electric heating devices 44.

[0069] Even though the water circuit 40 is provided in embodiment 3 to allow water to flow through it as a heating medium, this is not a limitation. For example, an antifreeze solution consisting mainly of ethylene glycol can be used as a heating medium.

[0070] In embodiment 3, a configuration was further described in which the engine heater 43, which is configured to absorb the exhaust heat from the engine into the water, is connected to the water circuit 40. However, this is not a limitation. For example, the exhaust heat generated during the movement of the vehicle, such as heat emitted by an electric motor and a battery provided in the vehicle, can be absorbed in the water flowing through the water circuit 40.

[0071] The Fig. Figure 10 shows a schematic view of the vehicle air conditioning unit according to embodiment 4. Here, the same components are designated with the same reference numerals as in the embodiments described above.

[0072] As this is shown in the Fig. As shown in Figure 10, the refrigerant circuit 20 of this vehicle air conditioning unit has a control valve 34 with a refrigerant inlet and a refrigerant outlet, and it is configured to adjust the opening within two ranges, namely an expansion range and a condensation pressure adjustment range.

[0073] More precisely, the refrigerant inlet side of the radiator 15 is connected to the refrigerant supply side of the compressor 21 to form refrigerant flow channel 20a. Meanwhile, the refrigerant inlet side of the control valve 34 is connected to the refrigerant outlet side of the radiator 15 to form refrigerant flow channel 20b. Within refrigerant flow channel 20b, the expansion valve 25 for refrigerant with heat transfer and the gas / liquid separator 29 are located, in order of upstream flow direction. The refrigerant inlet side of the outdoor heat exchanger 22 is connected to the refrigerant outlet side of the control valve 34 to form refrigerant flow channel 20c. The refrigerant suction side of the compressor 21 is connected to the refrigerant outlet side of the outdoor heat exchanger 22 to form refrigerant flow channel 20d.In the refrigerant flow channel 20d, the first solenoid valve 26a and the manifold 30 are arranged in sequence from the upstream side of the refrigerant flow direction. The high-pressure refrigerant inlet side of the internal heat exchanger 23 is connected to the refrigerant flow channel 20b to form the refrigerant flow channel 20e. In the refrigerant flow channel 20e, the second solenoid valve 26b and the first check valve 27a are arranged in sequence from the upstream side of the refrigerant flow direction. The refrigerant inlet side of the heat exchanger 14 is connected to the high-pressure refrigerant outlet side of the internal heat exchanger 23 to form the refrigerant flow channel 20f. The heat exchanger expansion valve 28 is located in the refrigerant flow channel 20f.The low-pressure refrigerant inlet side of the internal heat exchanger 23 is connected to the refrigerant outlet side of the heat exchanger 14 to form refrigerant flow channel 20g. The section of refrigerant flow channel 20d between the first solenoid valve 26a and the manifold 30 is connected to the low-pressure refrigerant outlet side of the internal heat exchanger 23 to form refrigerant flow channel 20h. The refrigerant inlet side of the gas / liquid separator 22a is connected to the refrigerant outlet side of the external heat exchanger 22 in parallel with refrigerant flow channel 20d to form refrigerant flow channel 20i. The third solenoid valve 26c is located in refrigerant flow channel 20i.The refrigerant flow channel 20e downstream of the first check valve 27a in the refrigerant flow direction is connected to the refrigerant discharge side of the gas / liquid separator 22a via the subcooling section 22b, thus forming the refrigerant flow channel 20j. The second check valve 27b is located in the refrigerant flow channel 20j. The refrigerant suction side of the compressor 21 is connected to the gas / liquid separator 29, thereby forming the refrigerant flow channel 20k as a bypass circuit. The fourth solenoid valve 26d is located in the refrigerant flow channel 20k.

[0074] During the heating operation of the vehicle air conditioning unit with the configuration described above, the refrigerant flow passage of the control valve 34 in the refrigerant circuit 20 is set to the expansion section; the first solenoid valve 26a is open; the second to fourth solenoid valves 26b, 26c, and 26d are closed; and the compressor 21 is operated. As a result, the refrigerant discharged from the compressor 21 flows through the refrigerant circuit 20 in the following sequence: refrigerant flow channel 20a; the radiator 15; refrigerant flow channels 20b and 20c; the outdoor heat exchanger 22; and refrigerant flow channel 20d, and is drawn into the compressor 21. The refrigerant flowing through the refrigerant circuit 20 releases heat in the radiator 15 and absorbs heat in the outdoor heat exchanger 22.

[0075] During the first heating and dehumidification operation, the refrigerant flow passage of the control valve 24 in the refrigerant circuit 20 is additionally set to the expansion section; the first and second solenoid valves 26a and 26b are open; the third and fourth solenoid valves 26c and 26d are closed; and the compressor 21 is operated. As a result, the refrigerant discharged from the compressor 21 flows through the refrigerant circuit 20 in the following sequence: refrigerant flow channel 20a; the radiator 15; and refrigerant flow channel 20b. A portion of the refrigerant that has flowed through refrigerant flow channel 20b flows through the refrigerant circuit 20 in the following sequence: refrigerant flow channel 20c; the outdoor heat exchanger 22; and refrigerant flow channel 20d, and is then drawn into the compressor 21.The remaining refrigerant, which has flowed through refrigerant flow channel 20b, flows through the refrigerant circuit 20 in the following sequence: refrigerant flow channel 20e; the high-pressure side of the internal heat exchanger 23; refrigerant flow channel 20f; the heat exchanger 14; refrigerant flow channel 20g; the low-pressure side of the internal heat exchanger 23; and refrigerant flow channels 20h and 20d, and it is drawn into the compressor 21. The refrigerant flowing through the refrigerant circuit 20 releases heat in the radiator 15, and it absorbs heat in the heat exchanger 14 and the external heat exchanger 22.

[0076] When the fourth solenoid valve 26d is opened during the heating operation or the first heating and dehumidifying operation, the refrigerant flowing out of the heating element 15 flows into the gas / liquid separator 29, and part of the refrigerant flows through the refrigerant flow channel 20k, and then it flows into the area of ​​the compressor 21, through which the compressed refrigerant flows, in the same way as in embodiment 1.

[0077] As described above for the vehicle air conditioning unit according to the present embodiment, it is possible to increase the amount of heat released from the refrigerant in the heater 15 by increasing the amount of refrigerant discharged from the compressor 21 when the outside air temperature is low during the heating operation or the first heating and dehumidifying operation, in the same manner as in the embodiments described above. Therefore, it is possible to improve the heating function during the heating operation, and it is also possible to dehumidify the vehicle interior without impairing the heating function during the heating and dehumidifying operation.During heating operation and during heating and dehumidification operation, the refrigerant is additionally drawn into the compressor 21 through the collector 30, and therefore it is possible to prevent the amount of lubricating oil returning to the compressor 21 from becoming insufficient, even if the amount of circulating refrigerant is reduced.

[0078] In this case, the refrigerant circuit 20 according to embodiment 4 is applicable to the configuration which has the water circuit 40 according to embodiment 3.

[0079] The Fig. 11 and Fig. Figure 12 shows schematic views of the vehicle air conditioning unit according to embodiment 5. Here, the same components are designated with the same reference numerals as in the embodiments described above.

[0080] In the refrigerant circuit 20 of this vehicle air conditioning unit, the gas / liquid separator 22a and the subcooling section 22b are not provided in the same refrigerant circuit as in embodiment 4.

[0081] During cooling operation and during cooling and dehumidifying operation of the vehicle air conditioning unit with the configuration described above, the refrigerant flow passage of the control valve 34 in the refrigerant circuit 20 is set as the condensation pressure regulating section; the third solenoid valve 26c is open; the first, second, and fourth solenoid valves 26a, 26b, and 26d are closed; and the compressor 21 is operating. As shown in the Fig. As shown in Figure 11, the refrigerant discharged from the compressor 21 flows through the refrigerant circuit 20 in the following sequence: the refrigerant flow channel 20a; the radiator 15; the refrigerant flow channels 20b and 20c; the external heat exchanger 22; the refrigerant flow channels 20i and 20e; the high-pressure side of the internal heat exchanger 23; the refrigerant flow channel 20f; the heat exchanger 14; the refrigerant flow channel 20g; the low-pressure side of the internal heat exchanger 23; and the refrigerant flow channels 20h and 20d, and is drawn into the compressor 21. During cooling operation, the refrigerant flowing through the refrigerant circuit 20 releases heat into the outdoor heat exchanger 22 and absorbs heat in the heat exchanger 14. Meanwhile, during heating and dehumidifying operation, when the air mixing flap 16 is open, the refrigerant flowing through the refrigerant circuit 20 also releases heat into the radiator 15.During cooling operation and during cooling and dehumidifying operation, in the present embodiment a gaseous refrigerant and a liquid refrigerant flow into the collector 30, and therefore the liquid refrigerant accumulates in the collector 30, while the gaseous refrigerant is drawn into the compressor 21.

[0082] Meanwhile, during the heating operation and during the first heating and dehumidification operation, the refrigerant flows through the refrigerant circuit 20 in the same manner as in embodiment 4.

[0083] During the heating operation or the first heating and dehumidifying operation, the refrigerant flowing from the radiator 15 also flows into the gas / liquid separator 29, and a portion of it flows through the refrigerant flow channel 20k and then into the compressor area 21, through which the compressed refrigerant flows when the fourth solenoid valve 26d is open, as shown in the Fig. Figure 12 is shown (which shows the heating operation).

[0084] As described above for the vehicle air conditioning unit according to the present embodiment, it is possible to increase the amount of heat released from the refrigerant in the heater 15 by increasing the amount of refrigerant discharged from the compressor 21 when the outside air temperature is low during the heating operation or the first heating and dehumidifying operation, in the same manner as in the embodiments described above. Therefore, it is possible to improve the heating function during the heating operation, and it is also possible to dehumidify the vehicle interior without impairing the heating function during the heating and dehumidifying operation.During heating operation and during heating and dehumidification operation, the refrigerant is also drawn into the compressor 21 through the collector 30, and therefore it is possible to prevent the amount of lubricating oil returning to the compressor 21 from becoming insufficient, even if the amount of circulating refrigerant is reduced.

[0085] In the present embodiments, a configuration has been described in which the control valve 24, 34 has the expansion section, which is configured to expand the refrigerant flowing into the outdoor heat exchanger 22 during heating operation and during the first heating and dehumidification operation, and the condensation pressure regulating section, which is configured to control the condensation pressure of the refrigerant in the radiator 15 during cooling and dehumidification operation. However, this is not a limitation. For example, the expansion section and the condensation pressure regulating section, each having the adjustable opening, are individually provided in the refrigerant circuit 20 instead of the control valve 24, 34.

[0086] In the present embodiment, a configuration has also been described in which the refrigerant flow channel 20k is connected to the refrigerant inlet, which is connected to the area of ​​the compressor 21 through which the compressed refrigerant flows. However, this is not a limitation. If, for example, the compressor 21 is a two-stage compressor, the refrigerant flow channel 20k can be connected to the refrigerant flow channel between the first and second stages of the compressor 21. REFERENCE MARK LIST 10 air conditioning units 11 Airflow duct 11a Outside air intake 11b Interior air intake 11c Footwell outlet 11d Ventilation outlet 11e Defroster outlet 12 internal fans 13 Inlet switch flap 13b, 13c, 13d Exhaust valve 14 heat exchangers 15 radiators 16 Air mixing flap 20 Refrigerant circuit 20a to 20k Refrigerant flow channel (bypass circuit) 21 compressors 22 external heat exchangers 22a Gas / Liquid Separator 22b Lower cooling compartment 22c outdoor fan 23 internal heat exchangers 24 Control valve (first expansion valve) 25 Expansion valve for refrigerant with heat release (third expansion valve) 26a, 26b, 26c and 26d first to fourth solenoid valve 27a,27b first and a second check valve 28 Heat exchanger expansion valve (second expansion valve) 29 Gas / Liquid Separator 30 collectors 31 fourth expansion valve 33 refrigerant radiators 33a Heat exchanger part 34 Control valve 40 Water circuit (heating medium circuit) 41 Water pump (heating medium pump) 42 Heating core (heating medium radiator) 43 Engine heating elements (exhaust gas heat absorption section) 44 electric heating device (heating medium heating device, refrigerant heating device)

Claims

[1] Vehicle air conditioning unit with: a compressor (21) configured to compress and discharge a refrigerant; a radiator (15) configured to emit heat from the refrigerant; a heat exchanger (14) configured to absorb the heat in the refrigerant; an external heat exchanger (22) configured to release heat from the refrigerant or to absorb heat in the refrigerant; a first expansion valve (24) configured to expand the refrigerant flowing into the external heat exchanger (22); a second expansion valve (28) configured to expand the refrigerant flowing into the heat exchanger (14); a collector (30) configured to separate the refrigerant into a gas and a liquid and to allow the refrigerant to be drawn into the compressor (21), wherein the collector is provided in a refrigerant flow channel to a suction side of the compressor (21) into which the refrigerant is drawn; a heating refrigerant circuit (20a-20b-20c-20d-20e) configured to allow the refrigerant discharged by the compressor (21) to flow into the radiator (15) and release heat in the radiator (15), to allow the refrigerant flowing through the radiator (15) to flow into the outdoor heat exchanger (22) through the first expansion valve (24) and absorb the heat in the outdoor heat exchanger (22), and to allow the refrigerant flowing through the outdoor heat exchanger (22) to be drawn into the compressor (21) through the collector; a heating and dehumidifying refrigerant circuit (20a-20b-20c-20e, 20a-20b-20f-20g-20h-20i-20e) configured to allow the refrigerant discharged by the compressor (21) to flow into the radiator (15) and release heat in the radiator (15), to allow a portion of the refrigerant that has flowed through the radiator (15) to flow into the outdoor heat exchanger (22) through the first expansion valve (24) and absorb heat in the outdoor heat exchanger (22), to allow the remaining refrigerant that has flowed through the radiator (15) to flow into the heat exchanger (14) through the second expansion valve (28) and absorb heat in the heat exchanger (14), and to allow the refrigerant that has flowed through the The air has flowed through the external heat exchanger (22) and the heat exchanger (14), and is drawn into the compressor (21) through the collector; a third expansion valve (25) configured to expand the refrigerant flowing from the radiator (15) into the heating refrigerant circuit and the heating and dehumidifying refrigerant circuit; a gas / liquid separator (29) configured to separate the refrigerant expanded through the third expansion valve (25) into a gaseous refrigerant and a liquid refrigerant; and a bypass circuit (20k) configured to allow at least some of the gaseous refrigerant separated in the gas / liquid separator to flow into a section of the compressor (21) through which the compressed refrigerant flows; and a fourth expansion valve (31) configured to expand the refrigerant flowing through the bypass circuit; and a valve opening control device configured to control the opening of the third expansion valve (25) such that the degree of subcooling of the refrigerant in the radiator (15) becomes a predetermined value, and to control the opening of the fourth expansion valve (31) such that the quantity of refrigerant flowing through the bypass circuit becomes a predetermined value. [2] Vehicle air conditioning unit according to claim 1, further comprising: a heating medium pump (41) configured to discharge a heating medium; a heat exchanger part (33a) which is provided in the radiator (15) and configured to perform a heat exchange between the refrigerant flowing through the radiator (15) and the heating medium; a heating medium radiator (42) configured to emit heat from the heating medium; and a heating medium circuit (40) configured to allow the heating medium ejected by the heating medium pump to flow into the heat exchanger section and absorb the heat in the heat exchanger section, to allow the heating medium that has flowed through the heat exchanger section to flow into the heating medium radiator (42) and release the heat in the heating medium radiator (42), and to allow the heating medium that has flowed through the heating medium radiator (42) to be drawn into the heating medium pump. [3] Vehicle air conditioning unit according to claim 2, further comprising a heating medium heating device (44) configured to heat the heating medium flowing through the heating medium circuit. [4] Vehicle air conditioning unit according to claim 3, wherein the heating medium heating device has an electric heating device (44) configured to heat the heating medium flowing through the heating medium circuit. [5] Vehicle air conditioning unit according to claim 3, wherein the heating medium heating device has an exhaust gas heat absorption part (43) configured to allow the heating medium flowing through the heating medium circuit to absorb the heat emitted by another component, wherein the heating medium heating device is provided in the heating medium circuit. [6] Vehicle air conditioning unit according to any one of claims 1 to 5, further comprising a refrigerant heating device (44) configured to heat the refrigerant flowing through the heating refrigerant circuit and the heating and dehumidifying refrigerant circuit.

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