JP2018167768A - Air conditioner for vehicle - Google Patents

Abstract

To provide an improved air conditioner for a vehicle capable of adjusting the amount of a refrigerant circulating without using a liquid receiver to an appropriate amount.SOLUTION: An air conditioner 1A for a vehicle is provided with: a first refrigerant circuit provided with a refrigerant flow path for circulating a refrigerant and forming a first heat pump cycle; a second refrigerant circuit provided with the 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; a pressure sensitive part T1 measuring the pressure of the refrigerant in the first refrigerant circuit; an adjustment part 13 adjusting a flow rate of the refrigerant in a part except for the part of the refrigerant flow path of the second refrigerant circuit; and a control part 50A adjusting the amount of the refrigerant circulating in the first refrigerant circuit by controlling the adjustment part 13 on the basis of the pressure.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a vehicle air conditioner.

  In an air conditioner such as an in-vehicle air conditioner, a heat medium (refrigerant) that moves heat in an air conditioning cycle is used. In general, the refrigerant used in the air conditioner is easy to vaporize and difficult to handle in the open system. Therefore, in order to form a closed system, the refrigerant flow path of the air conditioner is filled with the refrigerant when the air conditioner is manufactured. The flow path is sealed. Therefore, it is not possible to increase or decrease the amount of refrigerant (refrigerant filling amount) filled in the refrigerant flow path when using the air conditioner.

  On the other hand, the driving state of the vehicle changes depending on the outside air temperature, the traveling state, and the like. As the operating state changes, the appropriate refrigerant charging amount also changes. For example, the appropriate refrigerant charging amount at the time of high load or high speed running of the engine is larger than the appropriate refrigerant charging amount at the time of low load or low speed running of the engine. If the refrigerant charging amount is too small, for example, there is a problem that the air conditioning performance is deteriorated. If the refrigerant charging amount is too large, for example, a problem such as damage to the air conditioner occurs.

  In order to maintain an appropriate amount of refrigerant that circulates in the refrigerant flow path even when the operating state changes, for example, a liquid receiver (receiver) that separates liquefied refrigerant into gas and liquid and sends out only liquid refrigerant , Also referred to as a liquid tank or the like) has been proposed (for example, Patent Document 1). Of the refrigerant filled in the refrigerant flow path, the refrigerant that becomes unnecessary according to the change in the operation state is temporarily held in the liquid receiver, so that the refrigerant flow is circulated regardless of the change in the operation state. Maintain an appropriate amount of refrigerant.

JP 2009-78631 A

  However, the liquid receiver requires a certain volume due to its nature. Therefore, there is a problem that it is difficult to reduce the size of the air conditioner including the liquid receiver.

  The objective of this indication is providing the improved vehicle air conditioner which can adjust the quantity of the refrigerant | coolant circulated without using a liquid receiver to an appropriate quantity.

  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 pressure sensitive measurement of the refrigerant pressure in the first refrigerant circuit The first refrigerant circuit by controlling the adjustment unit based on the pressure, the adjustment unit that adjusts the flow rate of the refrigerant in a portion of the second refrigerant circuit excluding a part of the refrigerant flow path, and the adjustment unit The control part which adjusts the quantity of the refrigerant | coolant to perform is taken.

  According to the present disclosure, it is possible to provide an improved vehicle air conditioner that can adjust the amount of refrigerant to be circulated without using a liquid receiver to an appropriate amount.

It is a block diagram 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 1st Embodiment. It is a flowchart which shows the operation | movement flow of ECU which concerns on 1st Embodiment. It is explanatory drawing of the heat pump type heating mode of the vehicle air conditioner which concerns on 2nd Embodiment. It is explanatory drawing of the heat pump type heating mode of the vehicle air conditioner which concerns on 3rd Embodiment. It is explanatory drawing of the heat pump type heating mode of the vehicle air conditioner which concerns on 4th 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. 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 (first heat exchanger) 11, a second water refrigerant heat exchanger (second heat exchanger) 12, a first on-off valve 13, A second on-off valve 14, a first expansion valve 16, a compressor (compressor) 38, an evaporator 48, a second expansion valve 37, an outdoor condenser 39, and a check valve 15 are provided. 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. The vehicle air conditioner 1 </ b> A further includes a coolant pipe that connects these components, the first water refrigerant heat exchanger 11, and the second water refrigerant heat exchanger 12.

  1 A of vehicle air conditioners are further provided with pressure sensor (pressure sensitive part) T1, temperature sensor (temperature sensitive part) T2, and ECU (control part) 50A.

  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 receives high-temperature and high-pressure refrigerant from the compressor 38 and releases heat from the high-temperature and high-pressure refrigerant to the coolant during a predetermined operation mode. 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. The refrigerant inlet of the compressor 38 is in communication with the first expansion valve 16.

  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 a refrigerant pipe. The refrigerant outlet of the second water / refrigerant heat exchanger 12 communicates with the refrigerant pipe that merges with the refrigerant inlet of the compressor 38 via the first expansion valve 16.

  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 first on-off valve 13 and the second on-off valve 14 are valves that adjust the opening and closing of the refrigerant flow path, for example, by electrical control. The first on-off valve 13 opens and closes the refrigerant flow path between the branch portion of the refrigerant flow path on the refrigerant delivery port side of the compressor 38 and the refrigerant introduction port of the outdoor capacitor 39. The second on-off valve 14 opens and closes the refrigerant flow path between the branch portion and the refrigerant inlet of the first water refrigerant heat exchanger 11.

  The first expansion valve 16 expands high-pressure refrigerant to low temperature and low pressure and sends it out. The delivered low-temperature and low-pressure refrigerant is introduced into the second water refrigerant heat exchanger 12. The first expansion valve 16 is a thermal expansion valve (TXV) having a function of automatically adjusting the amount of refrigerant sent out according to the temperature of the refrigerant sent out from the second water refrigerant heat exchanger 12. There may be.

  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 introduced into 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 delivered low-temperature and low-pressure refrigerant is introduced into 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 expansion valve having a function of automatically adjusting the amount of refrigerant to be introduced according to the temperature of the refrigerant sent from the evaporator 48.

  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 outlet 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 first 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, the first on-off valve 13 is closed, so that 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 first water refrigerant heat exchanger 11 and the second water refrigerant heat exchanger 12 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.

  The pressure sensor T1 is provided between the compressor 38 of the cooling refrigerant circuit and the first expansion valve 16, and measures the pressure of the refrigerant. In one example, the pressure sensor T <b> 1 measures the refrigerant pressure (delivery refrigerant pressure) at the refrigerant delivery port of the compressor 38.

  The pressure sensor T1 is a known pressure sensor such as a diaphragm pressure gauge that converts the displacement of the pressure receiving element into an electric signal, for example. When another pressure sensor is already provided between the compressor 38 and the first expansion valve 16, the pressure sensor may be used as the pressure sensor T1. This eliminates the need to provide a new pressure sensor for the implementation of the present disclosure.

  The temperature sensor T2 is provided in a coolant flow path between the engine cooling unit 40 and any of the first water refrigerant heat exchanger 11 and the second water refrigerant heat exchanger 12, and measures the temperature of the coolant. . In one example, the temperature sensor T2 measures the temperature of the coolant at the coolant delivery port of the engine cooling unit 40 (delivery coolant temperature). In another example, the temperature sensor T <b> 2 measures the temperature of the coolant (introduced coolant temperature) at the coolant inlet of the first water refrigerant heat exchanger 11.

  The temperature sensor T2 is a known temperature sensor such as a thermocouple temperature sensor using a thermoelectromotive force of a thermocouple in which two different types of metal wires are connected. In the case where another temperature sensor is already provided in the coolant flow path between the compressor 38 and one of the first water refrigerant heat exchanger 11 and the second water refrigerant heat exchanger 12, the temperature sensor May be used as the temperature sensor T2. This eliminates the need to provide a new temperature sensor for the implementation of the present disclosure.

  The ECU 50A includes a CPU and a ROM, and the CPU includes a computer that reads and executes a program stored in the ROM.

  The ECU 50A acquires the refrigerant pressure from the pressure sensor T1. Further, the ECU 50A acquires the temperature of the coolant from the temperature sensor T2. For example, the ECU 50A acquires the temperature and pressure by inputting electrical signals such as a voltage value or a current value indicating the temperature and pressure from the temperature sensor T2 and the pressure sensor T1, respectively.

  In one example, the ECU 50A opens and closes the first on-off valve 13 based on the result of comparison between the acquired refrigerant pressure and a predetermined value. For example, when the acquired refrigerant pressure is greater than a predetermined value, the ECU 50A opens the first on-off valve 13. Here, the predetermined value is a pressure determined based on the durability of a member such as rubber constituting the refrigerant pipe, and is, for example, 2.5 MPaG.

  In another example, the ECU 50A opens and closes the first on-off valve 13 based on the acquired refrigerant pressure, coolant temperature, and engine speed. For example, the ECU 50A obtains an appropriate refrigerant pressure (appropriate refrigerant pressure) from the acquired coolant temperature and engine speed, and then, based on the result of comparison between the appropriate refrigerant pressure and the delivery refrigerant pressure, the first The on-off valve 13 is opened and closed. Details will be described later with reference to the flowchart shown in FIG.

  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.

[Heat pump heating mode]
FIG. 2 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, as shown in FIG. 2, the first on-off valve 13 is closed and the second on-off valve 14 is switched to open. Further, the door 44a of the heater core 44 is opened (for example, fully opened).

  In the heat pump heating mode, the compressor 38 is further operated, so that the refrigerant is the first water refrigerant heat exchanger 11, the first expansion valve 16, the second water refrigerant heat exchanger 12, and the first expansion. The valve 16 and the compressor 38 flow cyclically in this order. Hereinafter, the refrigerant flow path for circulating the refrigerant in this order is referred to as a heating refrigerant circuit (first 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 introduced into the second water refrigerant heat exchanger 12. The introduced low-temperature and low-pressure refrigerant absorbs heat from the coolant in the second water refrigerant heat exchanger 12 and vaporizes. The vaporized low-pressure refrigerant is introduced into the compressor 38 and compressed. Thus, the heating refrigerant circuit forms a heat pump cycle (first 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.

  After the coolant passes through the engine cooling unit 40, a part of the coolant circulates in the first water refrigerant heat exchanger 11 and the heater core 44, and the other part circulates in the second water refrigerant heat exchanger 12 in this order. 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 delivered to the passenger compartment by the heater core 44. On the other hand, the coolant cooled in the second water refrigerant heat exchanger 12 can be sent to the engine cooling unit 40 to sufficiently cool the engine.

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

[Cooling mode]
FIG. 3 is an explanatory diagram of the cooling mode of the vehicle air conditioner 1A according to the first embodiment. In the cooling mode, as shown in FIG. 3, the first on-off valve 13 is switched to open and the second on-off valve 14 is switched to close. 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 (second refrigerant circuit). As shown in FIGS. 2 and 3, the cooling refrigerant circuit shares a part of the refrigerant flow path with the heating 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 (second heat pump cycle) that carries heat from the low temperature portion to the high temperature portion (from the evaporator 48 to the outdoor condenser 39).

  The coolant flows through the engine cooling unit 40, the first water refrigerant heat exchanger 11, and the heater core 44, and flows in parallel to the engine cooling unit 40 and the second water refrigerant heat exchanger 12. . When the coolant passes through the first water refrigerant heat exchanger 11, the second water refrigerant heat exchanger 12, and the heater core 44, the coolant hardly exchanges heat 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.

[Opening / closing operation of first on-off valve 13 in heat pump heating mode]
FIG. 4 is a flowchart showing an operation flow of the ECU 50A according to the first embodiment. This process is realized, for example, by the CPU of the ECU 50A reading and executing programs stored in the ROM. In one example, the flowchart shown in FIG. 4 is repeatedly executed at a predetermined cycle (for example, at intervals of 1 second).

  In addition, 1 A of vehicle air conditioners which concern on 1st Embodiment presuppose that the refrigerant | coolant is collect | recovered in the heating refrigerant circuit at the time of the operation | movement start in heat pump type heating mode. For example, the vehicle air conditioner 1A collects the refrigerant in the heating refrigerant circuit by switching the first on-off valve 13 and the second on-off valve 14 to close and open and operating the compressor 38, respectively. Can do.

  In step S1, the ECU 50A determines whether or not the vehicle air conditioner 1A is operating in the heat pump heating mode. When it is determined that the operation is not performed in the heat pump heating mode (step S1: No), it is not necessary to adjust the amount of refrigerant in the heating refrigerant circuit, and thus the flow is ended. On the other hand, when it determines with operate | moving in heat pump type heating mode (step S1: Yes), it progresses to step S2.

  In step S2, ECU 50A acquires the engine speed. In one example, the ECU 50A acquires the engine speed in the same manner as the conventional ECU acquires the engine speed.

  In step S3, the ECU 50A acquires the temperature of the coolant outlet of the engine cooling unit 40 from the temperature sensor T2. In one example, the ECU 50A performs correction based on pressure loss or the like on the temperature acquired from the temperature sensor T2.

  In step S4, the ECU 50A determines an appropriate refrigerant pressure from the acquired engine speed and the temperature of the coolant outlet of the engine cooling unit 40. In one example, ECU 50A stores in a storage device (not shown) a table (not shown) that describes the relationship between the engine speed, the temperature of the coolant outlet of engine cooling unit 40, and the appropriate refrigerant pressure. . Next, the ECU 50A obtains an appropriate refrigerant pressure from the engine speed and the temperature of the coolant outlet of the engine cooling unit 40 by referring to the table and performing interpolation or the like as necessary.

  In step S5, the ECU 50A determines the delivery refrigerant pressure from the pressure sensor T1. In one example, the ECU 50A performs correction based on pressure loss or the like on the temperature acquired from the pressure sensor T1.

  In step S6, the ECU 50A determines whether or not the delivery refrigerant pressure is greater than the appropriate refrigerant pressure. When it determines with it being large (step S6: Yes), it progresses to step S7. On the other hand, when it determines with it not being large (step S6: No), it progresses to step S8.

  In step S7, the ECU 50A opens the first on-off valve 13. In one example, the ECU 50A fully opens the first on-off valve 13. As a result, the amount of refrigerant to be circulated can be adjusted to an appropriate amount by allowing the refrigerant exceeding the appropriate amount to escape to the cooling refrigerant circuit, and the refrigerant pressure is too high. It is possible to prevent the refrigerant piping from being damaged.

  In step S8, the ECU 50A closes the first on-off valve 13. In one example, the ECU 50A completely closes the first on-off valve 13. Thereby, when the quantity of the refrigerant | coolant to circulate is an appropriate quantity, the quantity of a refrigerant | coolant can be maintained.

  Thus, 1 A of vehicle air conditioners which concern on 1st Embodiment are provided in the cooling fluid flow path between the engine cooling part 40 and the 1st heat exchanger 11, and measure the temperature of a cooling fluid. The temperature sensor T2 is provided, the pressure sensor T1 is provided between the compressor 38 of the first refrigerant circuit and the first heat exchanger 11, and the control unit 50A is based on the engine speed, temperature, and pressure. Thus, the opening and closing of the first on-off valve 13 is controlled.

  According to the first embodiment, the amount of refrigerant to be circulated without using a liquid receiver can be adjusted to an appropriate amount. Accordingly, since a positive displacement buffer such as a liquid receiver is not required, a wide operation region, that is, high performance can be maintained while reducing cost, weight, and volume. Furthermore, according to the first embodiment, it is possible to prevent damage to the refrigerant piping caused by the refrigerant pressure being too high.

(Second Embodiment)
FIG. 5 is an explanatory diagram of the heat pump heating mode of the vehicle air conditioner 1B according to the second embodiment. The components included in the vehicle air conditioner 1B are the same as those included in the vehicle air conditioner 1A except for the temperature sensor T3 (temperature sensing unit), the ECU 50B (control unit), and the position where the pressure sensor T1 is provided. There will be no explanation for them.

  The pressure sensor T1 is provided between the second water refrigerant heat exchanger 12 of the cooling refrigerant circuit and the compressor 38, and measures the pressure of the refrigerant. In one example, the pressure sensor T <b> 1 measures the refrigerant pressure (introduced refrigerant pressure) at the refrigerant inlet of the compressor 38.

  The pressure sensor T1 is preferably provided as close as possible to the refrigerant inlet of the compressor 38 in view of effects such as preventing a failure of the compressor 38 described later. However, the position where the pressure sensor T1 is provided is not limited as long as correction based on pressure loss or the like is performed from the pressure measured by the pressure sensor T1 and the pressure near the refrigerant inlet of the compressor 38 can be obtained.

  The temperature sensor T3 is provided between the second water refrigerant heat exchanger 12 of the cooling refrigerant circuit and the compressor 38, and measures the temperature of the refrigerant. In one example, the temperature sensor T3 measures the temperature of the refrigerant at the refrigerant inlet of the compressor 38 (introduced refrigerant temperature). The temperature sensor T3 is a known temperature sensor such as a thermocouple temperature sensor, for example. When another temperature sensor provided between the second water refrigerant heat exchanger 12 of the cooling refrigerant circuit and the refrigerant inlet of the compressor 38 already exists, the temperature sensor is used as the temperature sensor T3. May be. This eliminates the need to provide a new temperature sensor for the implementation of the present disclosure.

  The temperature sensor T3 is preferably provided as close as possible to the refrigerant inlet of the compressor 38 in view of effects such as preventing failure of the compressor 38 described later. However, the position where the temperature sensor T3 is provided is not limited as long as correction based on the pressure loss or the like can be performed from the temperature measured by the temperature sensor T3 and the temperature near the refrigerant inlet of the compressor 38 can be obtained.

  In one example, the ECU 50B switches between opening and closing of the first on-off valve 13 based on the introduced refrigerant pressure and the introduced refrigerant temperature. For example, the ECU 50B obtains the introduction superheat degree of the refrigerant to the compressor 38 from the introduction refrigerant pressure and the introduction refrigerant temperature, and compares the introduction superheat degree with the first predetermined value. Here, the introduction superheat degree is defined by the difference between the introduction refrigerant temperature and the saturation temperature when the introduction refrigerant temperature is higher than the saturation temperature determined based on the type of refrigerant and the introduction refrigerant pressure.

  In one example, the ECU 50B includes a CPU and a ROM, and the CPU includes a computer that reads and executes a program stored in the ROM. The ECU 50B receives electrical signals such as a voltage value or a current value indicating pressure and temperature from the pressure sensor T1 and the temperature sensor T3, respectively.

  In one example, the ECU 50B stores a table (not shown) describing the relationship between the refrigerant pressure and the saturation temperature in a storage device (not shown). Next, the ECU 50B obtains the introduction heating degree by performing interpolation or the like as necessary with reference to the table from the pressure and temperature acquired from the pressure sensor T1 and the temperature sensor T3.

  As the introduction superheat degree decreases, the density of the refrigerant increases and the efficiency of the compressor 38 is improved. However, when the introduced superheat degree approaches 0 ° C. and the liquefied refrigerant flows into the compressor 38, the compressor 38 breaks down. Therefore, the ECU 50B opens the first on-off valve 13 when the introduction superheat degree is smaller than the first predetermined value. Here, the first predetermined value is 5 ° C., for example. By switching the first on-off valve 13 to open and allowing some of the refrigerant to escape to the cooling refrigerant circuit, the degree of superheating introduced increases as the pressure in the heating refrigerant circuit decreases. Therefore, failure of the compressor 38 can be prevented.

  On the other hand, the higher the introduction superheat degree, the lower the density of the refrigerant and the worse the efficiency of the compressor 38. Therefore, the ECU 50B closes the first on-off valve 13 when the introduction superheat degree is larger than the second predetermined value. Here, the second predetermined value is a value larger than the first predetermined value, for example, an arbitrary value between 10 ° C. and 20 ° C. By switching the first on-off valve 13 to be closed and confining the refrigerant in the heating refrigerant circuit, an increase in the degree of introduced superheat is also suppressed as the pressure drop in the heating refrigerant circuit is suppressed. Therefore, deterioration of the efficiency of the compressor 38 can be suppressed.

  The operation in the cooling mode of the vehicle air conditioner 1B according to the second embodiment is the same as that of the cooling mode of the vehicle air conditioner 1A according to the first embodiment, and a description thereof will be omitted.

  Thus, the vehicle air conditioner 1B according to the second embodiment includes the temperature sensor T3 that is provided between the second heat exchanger 12 of the heating refrigerant circuit and the compressor 38 and measures the temperature of the refrigerant. The pressure sensor T1 is provided between the second heat exchanger 12 of the heating refrigerant circuit and the compressor 38, and the ECU 50B controls the opening and closing of the first on-off valve 13 based on temperature and pressure.

  According to the second embodiment, the amount of refrigerant to be circulated without using the liquid receiver can be adjusted. Furthermore, failure of the compressor 38 can be prevented, and deterioration of the efficiency of the compressor 38 can be suppressed.

(Third embodiment)
FIG. 6 is an explanatory diagram of the heat pump heating mode of the vehicle air conditioner 1C according to the third embodiment. The components included in the vehicle air conditioner 1C are the same as those included in the vehicle air conditioner 1B except for the ECU 50C (control unit) and the position where the pressure sensor T1 and the temperature sensor T3 are provided. Description is omitted.

  The pressure sensor T1 is provided between the first water refrigerant heat exchanger 11 and the first expansion valve 16 of the cooling refrigerant circuit, and measures the pressure of the refrigerant. In one example, the pressure sensor T1 measures the pressure of the refrigerant at the refrigerant delivery port of the first water refrigerant heat exchanger 11 (delivery refrigerant pressure).

  The pressure sensor T1 is provided as close as possible to the refrigerant outlet of the first water refrigerant heat exchanger 11 in view of the effect of guaranteeing the liquefaction of the refrigerant by the first water refrigerant heat exchanger 11 described later. preferable. However, the pressure sensor T1 is provided as long as the pressure near the refrigerant outlet of the first water-refrigerant heat exchanger 11 can be obtained by correcting the pressure based on the pressure measured by the pressure sensor T1. There is no restriction on the position.

  The temperature sensor T3 is provided between the first water refrigerant heat exchanger 11 and the first expansion valve 16 in the cooling refrigerant circuit, and measures the temperature of the refrigerant. In one example, the temperature sensor T3 measures the temperature of the refrigerant at the refrigerant outlet of the first water-refrigerant heat exchanger 11 (delivery refrigerant temperature).

  The temperature sensor T3 is provided as close as possible to the refrigerant outlet of the first water refrigerant heat exchanger 11 in view of the effect of guaranteeing the liquefaction of the refrigerant by the first water refrigerant heat exchanger 11 described later. preferable. However, the temperature sensor T3 is provided as long as the temperature near the refrigerant outlet of the first water-refrigerant heat exchanger 11 can be obtained from the temperature measured by the temperature sensor T3 based on pressure loss and the like. There is no restriction on the position.

  In one example, the ECU 50C controls the opening / closing of the first on-off valve 13 based on the measured pressure and temperature. For example, the ECU 50C obtains the delivery supercooling degree of the refrigerant from the first water refrigerant heat exchanger 11 from the measured pressure and temperature, and compares the delivery supercooling degree with the first predetermined value. Here, the delivery supercooling degree is defined by the difference between the saturation temperature and the measured pressure when the measured temperature is lower than the saturation temperature determined based on the type of refrigerant and the measured pressure. The

  In one example, the ECU 50C includes a CPU and a ROM, and the CPU includes a computer that reads and executes a program stored in the ROM. The ECU 50C receives electrical signals such as a voltage value or a current value indicating pressure and temperature from the pressure sensor T1 and the temperature sensor T3, respectively.

  In one example, the ECU 50C stores a table (not shown) describing the relationship between the refrigerant pressure and the saturation temperature in a storage device (not shown). Next, the ECU 50C obtains the degree of supercooling by referring to the table and performing interpolation as necessary from the pressure and temperature acquired from the pressure sensor T1 and the temperature sensor T3.

  When the delivery supercooling degree increases and the second water refrigerant heat exchanger 12 does not vaporize the refrigerant, the efficiency of the second water refrigerant heat exchanger 12 deteriorates. Therefore, the ECU 50C opens the first on-off valve 13 when the delivery supercooling degree is larger than the first predetermined value. Here, the first predetermined value is, for example, an arbitrary value between 10 ° C. and 15 ° C. By switching the first on-off valve 13 to open and allowing some of the refrigerant to escape to the cooling refrigerant circuit, the degree of supercooling delivered also decreases as the pressure in the heating refrigerant circuit decreases. Therefore, vaporization of the medium by the second water refrigerant heat exchanger 12 can be ensured, and deterioration of the efficiency of the second water refrigerant heat exchanger 12 can be suppressed.

  On the other hand, if the delivery supercooling degree decreases and the first water refrigerant heat exchanger 11 does not liquefy the refrigerant, the efficiency of the first water refrigerant heat exchanger 11 deteriorates. Therefore, the ECU 50C closes the first on-off valve 13 when the delivery supercooling degree is smaller than the second predetermined value. Here, the second predetermined value is a value smaller than the first predetermined value, for example, an arbitrary value between 3 ° C. and 5 ° C. By switching the first on-off valve 13 to be closed and confining the refrigerant in the heating refrigerant circuit, a decrease in the degree of supercooling is also suppressed as a decrease in the pressure in the heating refrigerant circuit is suppressed. Therefore, the liquefaction of the medium by the first water refrigerant heat exchanger 11 can be ensured, and deterioration of the efficiency of the first water refrigerant heat exchanger 11 can be suppressed.

  The operation in the cooling mode of the vehicle air conditioner 1C according to the third embodiment is the same as that of the cooling mode of the vehicle air conditioner 1A according to the first embodiment, and thus the description thereof is omitted.

  Thus, in the vehicle air conditioner 1C according to the third embodiment, the first expansion valve 16 that expands the refrigerant sent from the first heat exchanger 11 is provided in the heating refrigerant circuit, and the heating refrigerant A temperature sensor T3 is provided between the compressor 38 of the circuit and the first expansion valve 16, and measures the temperature of the refrigerant. The pressure sensor T1 is connected between the compressor 38 of the heating refrigerant circuit and the first expansion valve 16. The ECU 50C is provided in between, and controls opening and closing of the first on-off valve 13 based on the temperature and pressure.

  According to the third embodiment, the amount of refrigerant to be circulated without using the liquid receiver can be adjusted. Furthermore, the deterioration of the efficiency of the 1st water refrigerant | coolant heat exchanger 11 and the 2nd water refrigerant | coolant heat exchanger 12 can be suppressed.

(Fourth embodiment)
FIG. 7 is an explanatory diagram of the heat pump heating mode of the vehicle air conditioner 1D according to the fourth embodiment. Also in FIG. 7, the same components as those shown in FIG. 2 are denoted by the same reference numerals.

  In the fourth 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.

  In the fourth embodiment, the coolant inlet of the second water-refrigerant heat exchanger 12 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. Therefore, according to the fourth embodiment, the same effect as in 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, 1C, 1D Vehicle air conditioner 11 First water refrigerant heat exchanger 12 Second water refrigerant heat exchanger 13 First on-off valve 14 Second on-off valve 15 Check valve 16 First expansion Valve 37 Second expansion valve 38 Compressor 39 Outdoor condenser 40 Engine cooling unit 44 Heater core 44a Door 48 Evaporators 50A, 50B, 50C ECU
70 HVAC
T1 Pressure sensor T2 Temperature sensor T3 Temperature sensor F1 Fan

Claims (7)

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; ,
A pressure sensing unit for measuring the pressure of the refrigerant in the first refrigerant circuit;
An adjusting unit for adjusting the flow rate of the refrigerant in a portion of the second refrigerant circuit excluding the part of the refrigerant flow path;
A control unit for adjusting the amount of the refrigerant circulating in the first refrigerant circuit by controlling the adjustment unit based on the pressure;
A vehicle air conditioner. The adjustment unit is a first on-off valve provided in the second refrigerant circuit,
The controller opens the first on-off valve when the pressure value is greater than a predetermined value;
The vehicle air conditioner according to claim 1. A compressor that is provided in the partial refrigerant flow path and compresses the refrigerant;
A first heat exchanger that is provided in the first refrigerant circuit and performs heat exchange for condensing the refrigerant and dissipating heat to a coolant delivered from a heating member of a vehicle;
A temperature sensing unit provided in a flow path of the coolant between the heat generating member and the first heat exchanger, and measuring a temperature of the coolant;
With
The adjustment unit is a first on-off valve provided in the second refrigerant circuit,
The pressure sensitive part is provided between the compressor of the first refrigerant circuit and the first heat exchanger,
The control unit controls opening and closing of the first on-off valve based on an engine speed, the temperature, and the pressure.
The vehicle air conditioner according to claim 1. A compressor that is provided in the partial refrigerant flow path and compresses the refrigerant;
A first heat exchanger that is provided in the first refrigerant circuit and performs heat exchange for condensing the refrigerant and dissipating heat to a coolant delivered from a heating member of a vehicle;
A second heat exchanger that is provided in the first refrigerant circuit and performs heat exchange by absorbing heat from the coolant and evaporating the refrigerant;
A temperature sensing unit provided between the second heat exchanger of the first refrigerant circuit and the compressor, and measuring a temperature of the refrigerant;
With
The adjustment unit is a first on-off valve provided in the second refrigerant circuit,
The pressure sensitive part is provided between the second heat exchanger of the first refrigerant circuit and the compressor,
The controller controls opening and closing of the first on-off valve based on the temperature and the pressure;
The vehicle air conditioner according to claim 1. The control unit obtains an introduction superheat degree of the refrigerant to the compressor based on the temperature value and the pressure value, and when the introduction superheat degree is smaller than a first predetermined value, the first When the second predetermined value larger than the first predetermined value is smaller than the introduction superheat degree, the first on-off valve is closed.
The vehicle air conditioner according to claim 4. A first heat exchanger that is provided in the first refrigerant circuit and performs heat exchange for condensing the refrigerant and dissipating heat to a coolant delivered from a heating member of a vehicle;
A first expansion valve that is provided in the first refrigerant circuit and expands the refrigerant delivered from the first heat exchanger;
A temperature sensing unit that is provided between the first heat exchanger and the first expansion valve of the first refrigerant circuit and measures the temperature of the refrigerant;
With
The adjustment unit is a first on-off valve provided in the second refrigerant circuit,
The pressure sensitive part is provided between the first heat exchanger of the first refrigerant circuit and the first expansion valve,
The controller controls opening and closing of the first on-off valve based on the temperature and the pressure;
The vehicle air conditioner according to claim 1. The control unit obtains a derived subcooling degree of the refrigerant from the first heat exchanger based on the temperature value and the pressure value, and calculates the derived subcooling degree from a first predetermined value. Is larger, the first on-off valve is opened, and if the second predetermined value smaller than the first predetermined value is larger than the derived subcooling degree, the first on-off valve is closed.
The vehicle air conditioner according to claim 6.

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