JP2018171984A - Vehicular air conditioner - Google Patents

Abstract

An improved vehicle air conditioner that uses a common refrigerant for cooling and heating. A vehicle air conditioner includes a refrigerant flow path for circulating a refrigerant, a first refrigerant circuit that forms a first heat pump cycle, and a refrigerant flow path for circulating the refrigerant, the first heat pump A second refrigerant circuit that forms a second heat pump cycle different from the first cycle, shares a part of the refrigerant flow path with the first refrigerant circuit, and a part of the second refrigerant circuit excluding a part of the refrigerant flow path And a first expansion valve 16 that senses the pressure of the refrigerant and adjusts the flow rate of the refrigerant circulating in the second refrigerant circuit according to the temperature and the pressure. The second refrigerant circuit is provided in a part of the refrigerant flow paths and includes a temperature sensing unit 16A that senses the temperature of the refrigerant, and the second refrigerant circuit according to the temperature and pressure of the refrigerant when the refrigerant circulates through the first refrigerant circuit. Shut off the refrigerant that circulates. [Selection] Figure 1

Description

  The present disclosure relates to a vehicle air conditioner.

  As a conventional heating device for a vehicle, a hot water heater that heats a vehicle interior by using engine cooling water that has become high temperature is often used. Further, as a conventional cooling device for a vehicle, a heat pump type cooling device that cools the air sent into the passenger compartment with a low-temperature refrigerant of the heat pump is generally employed.

  Patent Document 1 can improve the heating performance over the existing one by adding a configuration that heats the cooling water of the hot water heater using a heat pump while using an existing hot water heater as a basis. An air conditioner for a vehicle is disclosed.

JP-A-10-76837

  The air conditioner for vehicles of patent document 1 is a structure which utilizes the structure of a heat pump only for heating, and the operation | movement at the time of cooling was not examined. That is, when a cooling function is added to the heating device of Patent Document 1, it has not been studied how to use the heat pump for both heating and cooling, and how to switch between them.

  An object of the present disclosure is to provide an improved vehicle air conditioner that uses a common refrigerant for cooling and heating.

  An air conditioner for a vehicle according to an aspect of the present disclosure includes a refrigerant flow path that circulates a refrigerant, includes a first refrigerant circuit that forms a first heat pump cycle, and a refrigerant flow path that circulates the refrigerant. A second heat pump cycle different from the heat pump cycle of the first refrigerant circuit, a second refrigerant circuit sharing a part of the refrigerant flow path with the first refrigerant circuit, and a part of the refrigerant flow path removed from the second refrigerant circuit And a first expansion valve that senses the pressure of the refrigerant and adjusts the flow rate of the refrigerant that circulates through the second refrigerant circuit in accordance with the temperature and pressure of the refrigerant. The valve is provided in a part of the refrigerant flow paths and includes a temperature sensing unit that senses the temperature, and the second refrigerant circuit is provided according to the temperature and pressure of the refrigerant when the refrigerant circulates through the first refrigerant circuit. A configuration is adopted that blocks the circulating refrigerant.

  According to the present disclosure, it is possible to provide an improved vehicle air conditioner that uses a common refrigerant for cooling and heating.

It is a block diagram of the vehicle air conditioner which concerns on 1st Embodiment. It is explanatory drawing of a 1st expansion valve. It is explanatory drawing of a 2nd expansion valve. It is a graph which shows the operating characteristic of a 2nd expansion valve. It is a graph which shows the operating characteristic of a 1st expansion valve and a 2nd expansion valve. It is explanatory drawing of the air_conditioning | cooling mode of the vehicle air conditioner which concerns on 1st Embodiment. It is explanatory drawing of the heat pump type heating mode of the vehicle air conditioner which concerns on 1st Embodiment. It is explanatory drawing of the air_conditioning | cooling mode of the vehicle air conditioner which concerns on 2nd Embodiment.

  Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a configuration diagram of a vehicle air conditioner 1A according to the first embodiment. FIG. 2 is an explanatory diagram of the first expansion valve 16. The vehicle air conditioner 1A is a device that is mounted on a vehicle having an engine (internal combustion engine) as a heat generating component and performs air conditioning in the passenger compartment.

  The vehicle air conditioner 1A includes a first water refrigerant heat exchanger 11, a second water refrigerant heat exchanger 12, an on-off valve 13, a first expansion valve 16, a compressor (compressor) 38, an evaporator 48, a second Expansion valve 37, outdoor condenser 39, and check valve 15. 1 A of vehicle air conditioners are further provided with refrigerant | coolant piping which connects these components.

  The vehicle air conditioner 1 </ b> A further includes an engine cooling unit 40 and a heater core 44. 1 A of vehicle air conditioners are further provided with the coolant piping which connects these components, the 1st water refrigerant | coolant heat exchanger 11, and the 2nd water refrigerant | coolant heat exchanger 12. FIG.

  The first water-refrigerant heat exchanger 11 (condenser) has a passage through which a high-temperature and high-pressure refrigerant flows and a passage through which a cooling liquid flows, and performs heat exchange between the refrigerant and the cooling liquid. The first water refrigerant heat exchanger 11 is supplied with a high-temperature and high-pressure refrigerant from the compressor 38 in a predetermined operation mode, and releases heat from the high-temperature and high-pressure refrigerant to the coolant. Thereby, the 1st water refrigerant | coolant heat exchanger 11 condenses a high temperature / high pressure refrigerant | coolant.

  The coolant inlet of the first water-refrigerant heat exchanger 11 is communicated with the coolant outlet of the engine cooling unit 40 via the coolant pipe. The coolant introduction port of the engine cooling unit 40 is communicated with the heater core 44 via a coolant pipe. The refrigerant inlet of the first water refrigerant heat exchanger 11 is communicated with the refrigerant outlet of the compressor 38 via the refrigerant pipe, and the refrigerant outlet of the first water refrigerant heat exchanger 11 is the first expansion valve. 16 is communicated.

  The second water-refrigerant heat exchanger 12 (evaporator) has a passage through which a low-temperature and low-pressure refrigerant flows and a passage through which a coolant flows, and performs heat exchange between the refrigerant and the coolant. In the second water refrigerant heat exchanger 12, a low-temperature and low-pressure refrigerant is introduced from the first expansion valve 16 during a predetermined operation mode, and heat is transferred from the coolant to the low-temperature and low-pressure refrigerant. As a result, the second water refrigerant heat exchanger 12 vaporizes the low-temperature and low-pressure refrigerant.

  The coolant inlet of the second water refrigerant heat exchanger 12 is communicated with the coolant outlet of the engine cooling unit 40 via the coolant pipe, and the coolant outlet of the second water refrigerant heat exchanger 12 is The coolant is connected to the coolant inlet of the engine cooling unit 40 via the coolant pipe. The refrigerant inlet of the second water-refrigerant heat exchanger 12 is communicated with the first expansion valve 16 via the refrigerant pipe, and the refrigerant delivery port is communicated with the refrigerant pipe that merges with the refrigerant inlet of the compressor 38. Yes.

  Thus, regarding the coolant flow path, the first water refrigerant heat exchanger 11 and the second water refrigerant heat exchanger 12 of the vehicle air conditioner 1A communicate with the engine cooling unit 40 in parallel. As a result, the pump for pumping the coolant can be reduced in size as compared with the case of communicating in series.

  The on-off valve 13 is a valve that adjusts the opening and closing of the refrigerant flow path, for example, by electrical control. The on-off valve 13 opens and closes the refrigerant flow path between the refrigerant flow branch B on the refrigerant delivery port side of the compressor 38 and the refrigerant inlet of the outdoor condenser 39.

  The first expansion valve 16 expands high-pressure refrigerant to low temperature and low pressure and sends it out. The sent low-temperature and low-pressure refrigerant is sent to the second water refrigerant heat exchanger 12. The first expansion valve 16 includes a temperature sensing portion 16A, a connection portion 16B, and a main body portion (pressure sensitive adjustment portion) 16C. The temperature of the refrigerant sensed by the temperature sensing portion 16A and the pressure sensed by the main body portion 16C. Accordingly, a temperature expansion valve (TXV) having a function of automatically adjusting the flow rate of the refrigerant to be delivered is provided.

  The temperature sensing unit 16A senses the temperature of the refrigerant. In one example, the temperature sensing part 16A is a temperature sensing cylinder attached to the surface of the refrigerant pipe in the vicinity of the refrigerant inlet of the compressor 38. The temperature sensing cylinder is filled with a medium that expands in accordance with the temperature of the refrigerant transmitted through the wall of the refrigerant pipe formed of the heat conductive member. In another example, the temperature sensing unit 16A is a temperature sensing cylinder attached to the inside of the refrigerant pipe in the vicinity of the refrigerant inlet of the compressor 38.

  The connecting portion 16B connects the temperature sensing portion 16A and the main body portion 16C so that the main body portion 16C can operate according to the temperature sensed by the temperature sensing portion 16A. In one example, the connection portion 16B is a capillary tube that transfers a part of the medium filled in the temperature sensing portion 16A to the main body portion 16C. The higher the temperature sensed by the temperature sensing part 16A, the greater the amount of medium transferred by the connection part 16B.

  As shown in FIG. 2, the main body portion 16C includes a medium receiving portion 16a, a connecting rod 16b, an urging portion 16c, a refrigerant introduction port 16d, a bottleneck portion 16e, a refrigerant delivery port 16f, and a valve body 16g. The main body portion 16C automatically adjusts the flow rate of the refrigerant to be delivered according to the temperature sensed by the temperature sensing portion 16A and the pressure from the refrigerant at the refrigerant delivery port 16f (outlet side) sensed by the valve body 16g. .

  The medium receiving unit 16a communicates with the temperature sensing unit 16A and the connection unit 16B, and receives the medium transferred from the temperature sensing unit 16A via the connection unit 16B. The medium is sealed between the temperature sensing part 16A, the connection part 16B, and the medium receiving part 16a. The greater the amount of medium received, the higher the pressure inside the medium receiver 16a.

  The connecting rod 16b connects the medium receiving portion 16a and the valve body 16g. The upper end of the connecting rod 16b forms a part of the inner wall of the medium receiving portion 16a, and the pressure inside the medium receiving portion 16a acts on the connecting rod 16b as a force that pushes the connecting rod 16b downward in FIG.

  The urging portion 16c urges the valve body 16g upward in FIG. In one example, the urging portion 16c is a coil spring.

  The refrigerant introduction port 16d introduces a high-temperature and high-pressure refrigerant sent from the first water-refrigerant heat exchanger 11. The flow of the introduced refrigerant is indicated by an arrow A1 in FIG.

  The bottleneck portion 16e allows the refrigerant introduction port 16d and the refrigerant delivery port 16f to communicate with each other and adiabatic expansion of the high-temperature and high-pressure refrigerant introduced to the refrigerant introduction port 16d. The adiabatically expanded refrigerant becomes a low-temperature and low-pressure refrigerant and is delivered to the refrigerant outlet 16f.

  The refrigerant outlet 16f delivers a low-temperature and low-pressure refrigerant. The flow of the delivered refrigerant is indicated by an arrow A2 in FIG. The sent refrigerant is sent to the second water-cooled heat exchanger 12.

  The valve body 16g adjusts the opening degree of the bottleneck portion 16e. In FIG. 2, the force received from the urging portion 16c and the pressure received from the refrigerant at the refrigerant delivery port 16f act as upward forces on the valve body 16g, and the pressure received from the refrigerant at the refrigerant inlet 16d and the connecting rod The force received from 16b acts as a downward force. When the downward force is smaller than the upward force, the valve body 16g closes the narrow portion 16e. As the downward force becomes larger than the upward force, the valve body 16g is pushed downward in FIG. 2, and the opening degree of the bottleneck portion 16e increases.

  Reference is again made to FIG. The compressor 38 is driven by engine power or electricity to compress the introduced refrigerant to a high temperature and high pressure and send it out. The sent high-temperature and high-pressure refrigerant is sent to the first water refrigerant heat exchanger 11 or the outdoor condenser 39. The low-pressure refrigerant is introduced from the second water refrigerant heat exchanger 12 or the evaporator 48 into the compressor 38 via the junction pipe.

  The evaporator 48 is a device that performs heat exchange between a low-temperature and low-pressure refrigerant and air. The evaporator 48 is supplied with low-temperature and low-pressure refrigerant during cooling operation, dehumidifying operation, or temperature control operation, and cools the intake air (air blown into the vehicle interior) supplied to the vehicle interior.

  The second expansion valve 37 expands high-pressure refrigerant to a low temperature and low pressure and sends it out. The sent low-temperature and low-pressure refrigerant is sent to the evaporator 48. The second expansion valve 37 is disposed in the vicinity of the evaporator 48. The second expansion valve 37 may be a temperature type expansion valve (TXV) having a function of automatically adjusting the amount of refrigerant to be sent according to the temperature of the refrigerant sent from the evaporator 48.

  As shown in FIG. 3, the second expansion valve 37 includes a medium sealing portion 37a, a connecting rod 37b, a biasing portion 37c, a refrigerant introduction port 37d, a bottleneck portion 37e, a refrigerant delivery port 37f, a valve body 37g, and a refrigerant. A flow path 37h is provided. Among these components, the urging portion 37c, the narrow passage portion 37e, and the valve body 37g are substantially the same as the urging portion 16c, the narrow passage portion 16e, and the valve body 16g included in the first expansion valve 16, respectively. Therefore, explanation is omitted.

  The medium enclosing part 37a is filled and sealed with a medium that expands according to the temperature of the upper end of the connecting rod 37b. The higher the temperature at the upper end of the connecting rod 37b, the higher the pressure inside the medium enclosure 37a.

  The connecting rod 37b connects the medium sealing part 37a and the valve body 37g. A part of the connecting rod 37b is exposed in the refrigerant flow path 37h. The connecting rod 37b is formed of a thermally conductive member, and transmits the temperature of the refrigerant flowing through the refrigerant flow path 37h to the medium enclosure 37a via the upper end of the connecting rod 37b. Thus, the connecting rod 37b functions as a temperature sensing unit that senses the temperature of the refrigerant flowing through the refrigerant flow path 37h.

  The upper end portion of the connecting rod 37b forms a part of the inner wall of the medium enclosure portion 37a. The pressure inside the medium sealing portion 37a acts on the connecting rod 37b as a force that pushes the connecting rod 37b downward in FIG.

  The refrigerant introduction port 37d introduces a high-pressure refrigerant sent from the outdoor capacitor 39. The flow of the introduced refrigerant is indicated by an arrow A1 in FIG.

  The refrigerant outlet 37f delivers a low-temperature and low-pressure refrigerant. The flow of the delivered refrigerant is indicated by an arrow A2 in FIG. The delivered refrigerant is delivered to the evaporator 48.

  The low-pressure refrigerant sent out from the evaporator 48 flows through the refrigerant flow path 37 h and is introduced into the compressor 38. The flow of the refrigerant flowing through the refrigerant flow path 37h is indicated by arrows A3 and A4 in FIG.

  Reference is again made to FIG. The outdoor condenser 39 has a passage through which the refrigerant flows and a passage through which the air flows. For example, the outdoor condenser 39 is disposed near the top of the vehicle in the engine room and exchanges heat between the refrigerant and the outside air. A high-temperature and high-pressure refrigerant is passed through the outdoor condenser 39 in the cooling mode and the dehumidifying mode, and heat is discharged from the refrigerant to the outside air. Outside air is blown onto the outdoor condenser 39 by, for example, a fan. A reservoir tank (not shown) may be provided on the refrigerant delivery side of the outdoor condenser 39.

  The check valve 15 is a valve that is provided in the refrigerant flow path between the compressor 38 and the evaporator 48 and prevents the refrigerant from flowing back in the operation mode in which the refrigerant does not flow to the outdoor condenser 39 and the evaporator 48. Here, an operation mode in which the on-off valve 13 is closed and the refrigerant flows through the refrigerant circuit passing through the second water refrigerant heat exchanger 12 and the first water refrigerant heat exchanger 11 will be considered. In this operation mode, since the on-off valve 13 is closed, the refrigerant circuit passing through the outdoor condenser 39 and the evaporator 48 is shut off. However, even in this case, if the temperature of the outside air is low, the refrigerant pressure in the outdoor condenser 39 and the evaporator 48 may be low. When this pressure drop occurs, the refrigerant flowing in the refrigerant circuits of the second water refrigerant heat exchanger 12 and the first water refrigerant heat exchanger 11 flows back to the refrigerant circuit on the evaporator 48 side. As a result, the amount of refrigerant in the refrigerant circuit passing through the second water refrigerant heat exchanger 12 and the first water refrigerant heat exchanger 11 deviates from the optimum range, and the efficiency of this heat pump cycle is reduced. . However, the presence of the check valve 15 can avoid such inconvenience.

  The engine cooling unit 40 includes a water jacket for flowing a coolant around the engine (heat generating member) and a pump for flowing the coolant to the water jacket, and releases heat from the engine to the coolant flowing in the water jacket. The pump is rotated by the power of the engine, for example. The engine cooling unit 40 may include a radiator that releases heat to the outside air when the amount of exhaust heat of the engine increases. The coolant passage of the engine cooling unit 40 is communicated with the heater core 44 through the first water refrigerant heat exchanger 11.

  The cooling liquid is an antifreeze liquid such as LLC (Long Life Coolant) and is a liquid for transporting heat.

  The configuration for transferring the coolant may be only the pump of the engine cooling unit 40. Thereby, reduction of the cost of an apparatus and reduction of the installation space of an apparatus can be aimed at. In order to increase the transfer capability of the coolant, a pump may be added to another portion of the coolant pipe.

  The heater core 44 is a device that performs heat exchange between the coolant and air. Heated coolant is supplied to the heater core 44, and heat is released to intake air (air blown into the vehicle interior) that is sent into the vehicle interior during the heating operation. The heater core 44 can adjust the amount of air passing through the opening of the door 44a. The door 44a can be opened and closed by electrical control. The door 44a is also called a mix door.

  The heater core 44 and the evaporator 48 are disposed in an intake passage of an HVAC (Heating, Ventilation, and Air Conditioning) 70 that supplies air into the vehicle interior. The HVAC 70 is provided with a fan F1 through which intake air flows.

  Next, the operation characteristics of the first expansion valve 16 and the second expansion valve 37 will be described.

  FIG. 4 is a graph showing the operating characteristics of the second expansion valve 37. In the graph shown in FIG. 4, the horizontal axis and the vertical axis are the temperature of the connecting rod 37b and the pressure of the refrigerant flow path 37h, respectively, and the opening start curve of the second expansion valve 37 is plotted. When the temperature rises or the pressure drops across the opening start curve of the second expansion valve 37, the valve body 37g starts to open the narrow portion 37e, that is, the second expansion valve 37 starts to open.

  Conversely, when the temperature drops or the pressure rises across the opening start curve of the second expansion valve 37, the valve body 37g closes the narrow passage 37e, that is, the second expansion valve 37 closes. That is, in the graph shown in FIG. 4, the second expansion valve 37 is closed on the upper side (left side) of the opening start curve of the second expansion valve 37.

  In other words, the opening start curve is a curve in which the lower limit value of the temperature at which the second expansion valve 37 opens is plotted against a given pressure.

  Here, in the following description, for the sake of simplicity, the pressure loss of the refrigerant from the refrigerant delivery port of the evaporator 48 to the compressor 38 is ignored, and the pressure of the refrigerant introduced into the compressor 38 is the pressure of the refrigerant flow path 37h. Is equal to Furthermore, for the sake of simplicity, it is assumed that the temperature of the refrigerant introduced into the compressor 38 is equal to the temperature of the connecting rod 37b, ignoring the temperature change of the refrigerant from the refrigerant delivery port of the evaporator 48 to the compressor 38. If necessary, the relationship shown in FIG. 4 may be corrected in consideration of pressure loss and temperature change.

  In order to bring the temperature of the connecting rod 37b close to the temperature of the refrigerant introduced into the compressor 38, the length of the refrigerant pipe from the second expansion valve 37 to the compressor 38 is preferably as short as possible. .

  As shown in FIG. 4, the pressure value of the saturation curve (working refrigerant saturation curve) of the refrigerant flowing through the refrigerant flow path 37h is higher than the pressure value of the opening start curve of the second expansion valve 37 at a temperature of 0 ° C. or higher. large. This means that the valve body 37g closes the bottleneck part 37e before the refrigerant introduced into the compressor 38 is liquefied (saturated). That is, by setting the opening start curve of the second expansion valve 37 as shown in FIG. 4, the refrigerant introduced into the compressor 38 can be prevented from liquefying, and the refrigerant liquefied by the compressor 38 is introduced. And can be prevented from being damaged.

  When the point indicating the state of the refrigerant introduced into the compressor 38 is on the right side (lower side) of the opening start curve of the second expansion valve 37 in the graph, the second expansion valve 37 is open. A high-pressure refrigerant is sent from the outdoor condenser 39 to the evaporator 48. Therefore, the pressure of the refrigerant introduced into the compressor 38 increases and the degree of superheat decreases. As described above, the second expansion valve 37 plays a role of adjusting the degree of superheat of the refrigerant introduced into the compressor 38.

  In one example, the operating characteristic of the second expansion valve 37 is a pressure at which the second expansion valve 37 starts to open when the temperature of the connecting rod 37b (refrigerant temperature) is 0 ° C. and 10 ° C., respectively. It is set by the ° C set value P1 and the 10 ° C set value P2.

  FIG. 5 is a graph showing operating characteristics of the first expansion valve 16 and the second expansion valve 37. In the graph shown in FIG. 5, the horizontal axis and the vertical axis represent the temperature of the temperature sensing part 16A or the connecting rod 37b and the pressure of the refrigerant delivery port 16f or the refrigerant flow path 37h, respectively. And the opening start curve of the second expansion valve 37 is plotted. Similar to the opening start curve of the second expansion valve 37, the opening start curve of the first expansion valve 16 is a curve in which the lower limit value of the temperature at which the first expansion valve 16 opens is plotted against a given pressure. is there.

  In order to make the pressure of the refrigerant outlet 16f and the refrigerant flow path 37h on the same axis, in addition to the length of the refrigerant pipe from the second expansion valve 37 to the compressor 38, the first expansion valve 16 to the compressor The length of the refrigerant piping up to 38 is preferably as short as possible.

  Similarly to the operation characteristic of the second expansion valve 37, the operation characteristic of the first expansion valve 16 is the valve body 16g when the temperature (temperature of the refrigerant) of the temperature sensing part 16A is 0 ° C. and 10 ° C., respectively. Is set by a 0 ° C. set value P3 and a 10 ° C. set value P4, which are pressures at which the bottleneck portion 16e starts to open.

  The lower limit value of the temperature at which the first expansion valve 16 opens is larger than the lower limit value of the temperature at which the second expansion valve 37 opens with respect to the pressure value equal to or lower than the first predetermined value. For example, as shown in the graph of FIG. 5, the 0 ° C. set value P3 of the first expansion valve 16 is set lower than the 0 ° C. set value P1 of the second expansion valve 37. This creates a region R in which the first expansion valve 16 is closed but the second expansion valve 37 is open.

  The first predetermined value is, for example, the maximum value of the refrigerant pressure in the cooling mode described later, and is, for example, 0.25 MPaG. Thus, in the cooling mode, a region R in which the first expansion valve 16 is closed but the second expansion valve 37 is open is created.

  The opening start curve of the first expansion valve 16 and the opening start curve of the second expansion valve 37 have different slopes at the same temperature. For example, at the same temperature, the slope of the opening start curve of the first expansion valve 16 is smaller than the slope of the opening start curve of the second expansion valve 37. For example, the efficiency of the compressor 38 can be improved in the heat pump heating mode to be described later by increasing the slope of the opening start curve of the second expansion valve 37 to approach the working refrigerant saturation curve. In order to change the slope of the opening start curve of the first expansion valve 16 or the second expansion valve 37, the type of medium filled in the temperature sensing part 16A or the medium enclosing part 37a may be changed.

  The 0 ° C. set value P3 of the first expansion valve 16 is equal to a value obtained by subtracting 0.140 MPaG from the saturation pressure of the refrigerant at 0 ° C., and the 10 ° C. set value P4 of the first expansion valve 16 is 10 ° C. of the refrigerant. It is equal to the value obtained by subtracting 0.190 MPaG from the saturation pressure at. In one example, the 0 ° C. set value P1 of the second expansion valve 37 is equal to the value obtained by subtracting 0.010 MPaG from the saturation pressure of the refrigerant at 0 ° C., and the 10 ° C. set value P2 of the second expansion valve 37 is It is equal to the value obtained by subtracting 0.080 MPaG from the saturation pressure of the refrigerant at 10 ° C.

  The medium filled in the temperature sensing part 16A and the urging part 16c are selected so that the first expansion valve 16 satisfies the above properties. Further, the medium filled in the medium enclosing part 37a and the urging part 37c are also selected so that the second expansion valve 37 satisfies the above-mentioned properties. The medium is, for example, R-404A, R-410A, R-134a, R-32, HFO-1234yf, or a mixture thereof.

  Next, the operation of the vehicle air conditioner 1A will be described.

  The vehicle air conditioner 1A operates by being switched to several operation modes such as a hot water heating mode, a heat pump heating mode, a temperature control mode, and a cooling mode. The hot water heating mode is a mode in which the passenger compartment is heated without operating the heat pump. The heat pump heating mode is a mode in which the vehicle interior is heated by operating the heat pump. The cooling mode is a mode in which the passenger compartment is cooled by the action of the heat pump. The temperature adjustment mode is a mode in which the temperature and humidity of the air are adjusted by appropriately combining air cooling and dehumidification with a low-temperature refrigerant and air heating with a high-temperature coolant. Hereinafter, the heat pump heating mode and the cooling mode will be described as representative examples.

[Cooling mode]
FIG. 6 is an explanatory diagram of the cooling mode of the vehicle air conditioner 1A according to the first embodiment. In the cooling mode, the on-off valve 13 is opened as shown in FIG. Further, the door 44a of the heater core 44 is fully closed.

  In the cooling mode, when the compressor 38 is further operated, the refrigerant circulates through the outdoor condenser 39, the second expansion valve 37, the evaporator 48, the second expansion valve 37, and the compressor 38 in this order. Flowing. Hereinafter, the refrigerant flow path for circulating the refrigerant in this order is referred to as a cooling refrigerant circuit (first refrigerant circuit).

  The high-temperature and high-pressure refrigerant compressed by the compressor 38 dissipates heat to the air in the outdoor condenser 39 and condenses. The condensed refrigerant is expanded by the second expansion valve 37 to become a low-temperature and low-pressure refrigerant and is sent to the evaporator 48. The low-temperature and low-pressure refrigerant cools and evaporates the intake air sent into the passenger compartment by the evaporator 48. The vaporized low-pressure refrigerant is introduced into the compressor 38 and compressed. In this way, the cooling refrigerant circuit also forms a heat pump cycle (first heat pump cycle) that conveys heat from the low temperature portion to the high temperature portion (from the evaporator 48 to the outdoor condenser 39).

  As described above with reference to FIG. 5, in the cooling mode, the region R in which the first expansion valve 16 is closed but the second expansion valve 37 is open is created. Accordingly, in the cooling mode, as long as the temperature and pressure of the refrigerant introduced into the compressor 38 remain in the region R, the first expansion valve 16 is closed. That is, the main body portion 16C refers to FIG. 7 according to the temperature and pressure of the refrigerant when the temperature sensing portion 16A and the main body portion 16C included in the first expansion valve 16 circulate in the cooling refrigerant circuit in the cooling mode. The refrigerant circulating in the heating refrigerant circuit described later is shut off.

  According to the present disclosure, FIG. 7 is referred to in the cooling mode without separately providing an on-off valve that opens and closes the refrigerant flow path between the branch portion B and the refrigerant inlet of the first water refrigerant heat exchanger 11. Thus, the refrigerant circulating in the heating refrigerant circuit described later can be shut off. Therefore, the cost of the on-off valve can be reduced.

  In addition, when the 1st expansion valve 16 is closed, it is also considered that a refrigerant | coolant reaches | attains the 1st water refrigerant | coolant heat exchanger 11 provided between the branch part B and the 1st expansion valve 16. FIG. Even in such a case, the refrigerant is heated by the first water refrigerant heat exchanger 11, so that no stagnation of the refrigerant occurs between the branch portion B and the first water refrigerant heat exchanger 11.

  Note that when the operation of the vehicle air conditioner 1A is started, the temperature of the refrigerant may be high due to the outside air temperature or the like. In addition, the temperature of the refrigerant may temporarily increase due to a sudden change in the operating state. In these cases, the temperature and pressure of the refrigerant introduced into the compressor 38 may be on the lower side of the opening start curve of the first expansion valve 16, for example, as indicated by a point P5 shown in FIG. Then, since the 1st expansion valve 16 opens, even if it is a case where 1 A of vehicle air conditioners are operate | moving in air_conditioning | cooling mode, a refrigerant | coolant circulates through the heating refrigerant circuit later mentioned with reference to FIG.

  Even in such a case, the temperature of the refrigerant decreases while the vehicle air conditioner 1A operates in the cooling mode. Therefore, the temperature and pressure of the refrigerant introduced into the compressor 38 change to the upper side (left side) of the opening start curve of the first expansion valve 16 as indicated by a point P6 shown in FIG. By closing the expansion valve 16, it is possible to block the refrigerant circulating in the heating refrigerant circuit described later with reference to FIG.

  On the other hand, the coolant flows through the engine cooling unit 40, the first water refrigerant heat exchanger 11, and the heater core 44, and in parallel with this, the engine cooling unit 40 and the second water refrigerant heat exchanger 12 are passed through. Flowing. When the coolant passes through the first water refrigerant heat exchanger 11, the second water refrigerant heat exchanger 12, and the heater core 44, little heat is exchanged with the refrigerant or air. The heat dissipation of the cooling liquid is mainly performed by the radiator of the engine cooling unit 40. Since the engine becomes very hot, even if the outside air temperature is high, appropriate cooling can be performed by heat radiation by the radiator. Here, in the configuration in which the cooling liquid is supplied, a large amount of the cooling liquid may be supplied to the radiator side to reduce the flow on the heater core 44 side.

  Such an operation can sufficiently cool the passenger compartment.

[Heat pump heating mode]
FIG. 7 is an explanatory diagram of the heat pump heating mode of the vehicle air conditioner 1A according to the first embodiment. In the heat pump heating mode, the on-off valve 13 is closed as shown in FIG. Further, the door 44a of the heater core 44 is opened (for example, fully opened).

  In the heat pump heating mode, when the compressor 38 is further operated, the refrigerant is the first water refrigerant heat exchanger 11, the first expansion valve 16, the second water refrigerant heat exchanger 12, and the compressor 38. In this order. Hereinafter, the refrigerant flow path for circulating the refrigerant in this order is referred to as a heating refrigerant circuit (second refrigerant circuit).

  The high-temperature and high-pressure refrigerant compressed by the compressor 38 dissipates heat to the coolant in the first water refrigerant heat exchanger 11 and condenses. The condensed refrigerant is expanded by the first expansion valve 16 to become a low-temperature and low-pressure refrigerant, and is sent to the second water refrigerant heat exchanger 12. The low-temperature and low-pressure refrigerant is vaporized by absorbing heat from the coolant in the second water-refrigerant heat exchanger 12. The vaporized low-pressure refrigerant is introduced into the compressor 38 and compressed. In this way, the heating refrigerant circuit forms a heat pump cycle (second heat pump cycle) that carries heat from the low temperature portion to the high temperature portion (second water refrigerant heat exchanger 12 to first water refrigerant heat exchanger 11). To do.

  As shown in FIGS. 6 and 7, the heating refrigerant circuit shares a part of the refrigerant flow path with the cooling refrigerant circuit. And temperature sensing part 16A is provided in a part of common refrigerant flow path. Therefore, also in the heat pump heating mode, the temperature sensing unit 16A can sense the temperature of the refrigerant flowing through some of the shared refrigerant flow paths. That is, even in the heat pump heating mode, the first expansion valve 16 can be operated according to the temperature of the refrigerant introduced into the compressor 38.

  After the coolant passes through the engine cooling unit 40, a part of the coolant circulates in the order of the first water refrigerant heat exchanger 11, the heater core 44, and the second water refrigerant heat exchanger 12. Flowing.

  Here, the coolant that has absorbed heat from the engine by the engine cooling unit 40 is further heated by the first water refrigerant heat exchanger 11 and sent to the heater core 44. The coolant that has reached a high temperature can sufficiently heat the intake air that is sent into the passenger compartment by the heater core 44.

  The coolant that has passed through the heater core 44 has a temperature higher than that of the outside air, and the second water-refrigerant heat exchanger 12 can radiate heat to the refrigerant to vaporize the refrigerant. The coolant cooled in the second water-refrigerant heat exchanger 12 is sent to the engine cooling unit 40 to sufficiently cool the engine.

  With such an operation, the vehicle interior can be sufficiently heated.

(Second Embodiment)
FIG. 8 is an explanatory diagram of the cooling mode of the vehicle air conditioner 1B according to the second embodiment. Also in FIG. 8, the same components as those shown in FIG. 2 are denoted by the same reference numerals.

  In the second embodiment, the coolant inlet of the first water-refrigerant heat exchanger 11 is communicated with the heater core 44 via the coolant pipe, and the coolant outlet is connected to the engine cooling section via the coolant pipe. 40 is the same as the first embodiment except that it is communicated with 40. In the second embodiment, the coolant does not branch after passing through the engine cooling unit 40, but the first water refrigerant heat exchanger 11, the heater core 44, and the second water refrigerant heat exchange. The vessel 12 flows cyclically in this order.

  On the other hand, the heating refrigerant circuit and the cooling refrigerant circuit in the second embodiment have the same configurations as the heating refrigerant circuit and the cooling refrigerant circuit in the first embodiment, respectively. Therefore, according to the second embodiment, the same effect as the first embodiment can be obtained.

  The vehicle air conditioner according to the present disclosure is suitable for being applied to a vehicle.

1A, 1B Vehicle air conditioner 11 First water refrigerant heat exchanger 12 Second water refrigerant heat exchanger 13 On-off valve 15 Check valve 16 First expansion valve 16A Temperature sensing part 16B Connection part 16C Body part 37 First 2 expansion valve 38 compressor 39 outdoor condenser 40 engine cooling part 44 heater core 44a door 48 evaporator 70 HVAC
F1 fan

Claims (4)

A first refrigerant circuit comprising a refrigerant flow path for circulating the refrigerant and forming a first heat pump cycle;
A second refrigerant circuit comprising a refrigerant flow path for circulating the refrigerant, forming a second heat pump cycle different from the first heat pump cycle, and sharing a part of the refrigerant flow path with the first refrigerant circuit; ,
Provided in a portion excluding the part of the refrigerant flow path from the second refrigerant circuit, senses the pressure of the refrigerant, and circulates through the second refrigerant circuit according to the temperature and the pressure of the refrigerant. A first expansion valve for adjusting the flow rate of the refrigerant;
With
The first expansion valve is provided in the partial refrigerant flow path, includes a temperature sensing unit that senses the temperature, and the temperature and pressure of the refrigerant when the refrigerant circulates in the first refrigerant circuit. In response to shutting off the refrigerant circulating in the second refrigerant circuit,
Vehicle air conditioner. A compressor provided in the partial refrigerant flow path for compressing the refrigerant;
The temperature sensing unit senses the temperature of the refrigerant introduced by the compressor.
The vehicle air conditioner according to claim 1. A second expansion valve that is provided in the first refrigerant circuit and expands and sends out the introduced refrigerant;
The lower limit value of the temperature at which the first expansion valve opens is greater than the lower limit value of the temperature at which the second expansion valve opens, for a pressure value smaller than a predetermined value,
The vehicle air conditioner according to claim 2. The 0 ° C. set value of the first expansion valve is smaller than the 0 ° C. set value of the second expansion valve, and the 10 ° C. set value of the first expansion valve is 10 ° C. of the second expansion valve. Smaller than ℃ set value,
The vehicle air conditioner according to claim 3.

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