JP2010042698A - Air conditioner for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner for a vehicle capable of ensuring a predetermined flow rate of coolant by controlling movement of heat between a refrigeration cycle and a cooling water circuit. <P>SOLUTION: The air conditioner 1 for the vehicle performs control so as to perform heat exchange between the coolant and cooling water using a water coolant heat exchanger 11 when it satisfies a predetermined condition when a control mode is a dehumidification/heating mode. Specifically, the control device controls giving/receiving of heat of the coolant and water by controlling the opening/closing state of first to third changeover valves 14, 19, 22 and valve opening of a first expansion valve 12, and a calorific value of medium flowing in a different flow passage can be effectively used. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle air conditioner that provides conditioned air using a refrigeration cycle and a cooling water circuit.

A conventional vehicle air conditioner has a refrigeration cycle and a cooling water circuit. The evaporator, which is a component of the refrigeration cycle, is provided in the air conditioning duct, and the low-pressure refrigerant of the refrigeration cycle absorbs heat from the air passing through the air conditioning duct to cool the passing air. The cooling water circuit has a heater function for heating the air passing through the air conditioning duct using the engine cooling water as a heat source. The refrigerant of the refrigeration cycle and the cooling water of the cooling water circuit are configured to exchange heat with a water refrigerant heat exchanger (see, for example, Patent Document 1).
JP 2007-24470 A

  In the refrigeration cycle constituting the above-described conventional vehicle air conditioner, when the outside air temperature is low and the inside air mode is used as in winter, the high-low pressure difference of the refrigerant in the refrigeration cycle may be small. As described above, when the difference between the high and low pressures of the refrigerant in the refrigeration cycle is small, there is a problem that the refrigerant cannot be completely flown by the expansion valve, and a predetermined refrigerant flow rate cannot be secured.

  Therefore, the present invention has been made in view of the above-mentioned problems, and for vehicles that can secure a predetermined refrigerant flow rate by controlling the movement of heat between the refrigeration cycle and the cooling water circuit. An object is to provide an air conditioner.

  The present invention employs the following technical means in order to achieve the aforementioned object.

The invention according to claim 1 is an air conditioner for a vehicle that provides conditioned air into a vehicle interior using a cooling water circuit and a refrigeration cycle,
An air-conditioning air passage (5) having an air intake port on one end side and an air outlet to the vehicle interior on the other end side;
A blower for blowing air from the inlet side to the outlet side;
A cooling water circuit (4) through which cooling water for cooling a heat generating device mounted on the vehicle circulates;
The compressor (10) that compresses and discharges the refrigerant to high temperature and high pressure, the condenser (13) that condenses the refrigerant discharged from the compressor by exchanging heat with the outside air, and depressurizes the refrigerant condensed in the condenser A refrigeration cycle (3) including an evaporator (7) installed in the pressure reducing means (15), the air-conditioned air passage, and the refrigerant decompressed by the pressure reducing means absorbs heat from the air to evaporate and cools the air;
Provided between the compressor and the condenser, and has a refrigerant passage through which refrigerant discharged from the compressor passes and a cooling water passage through which cooling water passes, and passes through the refrigerant and cooling water passage through the refrigerant passage. A water-refrigerant heat exchanger (11) that exchanges heat with the cooling water that
A heater core (8) provided in the cooling water circuit, installed downstream of the evaporator in the conditioned air passage, and heats the air by exchanging heat with the cooling water;
Cooling water temperature detecting means for detecting the temperature of the cooling water;
Refrigerant state detecting means for detecting a state quantity of the refrigerant;
Air-conditioning mode setting means for setting each air-conditioning mode of cooling mode, heating mode and dehumidifying heating mode;
Air conditioning control means for controlling the flow path switching means based on the air conditioning mode set by the air conditioning mode setting means,
The refrigeration cycle switches between a flow path for the refrigerant discharged from the compressor to flow through the refrigerant passage to the condenser and a flow path for the refrigerant discharged from the compressor to flow to the condenser without passing through the refrigerant passage. Including flow path switching means (12, 21, 22),
When the air conditioning mode is the dehumidifying heating mode, the air conditioning control means has a shortage of heat quantity of the cooling water for executing the dehumidifying heating mode based on the detected cooling water temperature and the state quantity of the refrigerant. When the pressure of the refrigerant for executing the dehumidifying and heating mode is low, the vehicle air conditioner controls the flow path switching means so that the refrigerant passes through the refrigerant passage of the water-refrigerant heat exchanger Device.

  According to the first aspect of the present invention, when a predetermined condition is satisfied when the air conditioning mode is the dehumidifying heating mode, heat is exchanged between the refrigerant and the cooling water using the water refrigerant heat exchanger. Thereby, for example, even if the outside air temperature is low and the high / low pressure difference of the refrigerant is small, the high / low pressure difference of the refrigerant can be increased by heating the refrigerant with the cooling water. Therefore, the problem of the high / low pressure difference of the refrigerant is solved, so that the refrigerant can be circulated. Even if the amount of heat of the cooling water is insufficient, the amount of heat of the cooling water for executing the dehumidifying heating mode can be ensured by heating the cooling water with the refrigerant. In this way, the air conditioning control means controls the flow path switching means to control the transfer of heat between the refrigerant and the water, and can effectively use the amount of heat of the medium flowing in the different flow paths.

  In the invention according to claim 2, the decompression means has a nozzle (27) for decompressing and expanding the high-pressure refrigerant in an isentropic manner, and the high-pressure refrigerant is decompressed and expanded by the nozzle to generate a high-speed refrigerant flow. The ejector (25) is configured to circulate the low-pressure side refrigerant in the generated refrigerant flow and convert the expansion energy into pressure energy to increase the suction pressure of the compressor.

  According to the invention described in claim 2, since the ejector is included, the efficiency of the refrigeration cycle through which the refrigerant flows can be improved.

Furthermore, in the invention according to claim 3, the flow path switching means is
A bypass passage (21) in which the refrigerant discharged from the compressor bypasses the water-refrigerant heat exchanger and reaches the condenser;
A switching unit (22) that is provided in the bypass channel and switches the open / close state of the bypass channel;
The refrigerant discharged from the compressor passes through the water-refrigerant heat exchanger and reaches the condenser (17),
And a decompression section (12) provided between the water refrigerant heat exchanger and the condenser in the cycle flow path, wherein the decompression amount of the refrigerant passing therethrough is variable.

  According to the third aspect of the present invention, since the detour channel is provided with the switching unit, the air conditioning control unit controls the switching unit to be in the closed state, thereby allowing the refrigerant to flow through the cycle channel. The cycle flow path is provided with a pressure reducing part having a variable pressure reducing amount, and the air pressure control means controls the pressure reducing part so that there is no pressure reducing amount, that is, no pressure reducing, so that the difference between the high and low pressures of the refrigerant is small. Thus, the refrigerant can be circulated through the water refrigerant heat exchanger. If you do not want the refrigerant to flow through the water-refrigerant heat exchanger, set the switching unit in the open state and set the depressurization amount of the depressurization unit to a predetermined depressurization amount so that the refrigerant flows through the water-refrigerant heat exchanger. Instead, the refrigerant discharged from the compressor can be given to the condenser via the bypass channel. In this way, the air conditioning control means can switch between a state in which the refrigerant is circulated in the water refrigerant heat exchanger and a state in which the refrigerant is not circulated by controlling the flow path switching means.

Furthermore, in the invention according to claim 4, the refrigerant state detecting means detects the pressure of the refrigerant on the high pressure side of the refrigeration cycle as the refrigerant state quantity,
When the air conditioning mode is the dehumidifying heating mode, the air conditioning control means passes the water refrigerant heat exchanger when the detected cooling water temperature is equal to or higher than a predetermined temperature and the refrigerant pressure is equal to or lower than the predetermined pressure. Thus, the flow path switching means is controlled.

  According to the fourth aspect of the present invention, the air conditioning control means, when the predetermined condition is satisfied, that is, when the high pressure of the refrigerant is low and the cooling water can be used as a heat source capable of heating the refrigerant, the refrigerant is water. The flow path switching means is controlled so as to pass through the refrigerant heat exchanger. Therefore, the coolant having a predetermined pressure or lower can be heated by the cooling water having a predetermined temperature or higher. This eliminates the problem of the high / low pressure difference of the refrigerant, so that the refrigerant can be circulated.

  Furthermore, in the invention according to claim 5, the air conditioning control means, when the air conditioning mode is the dehumidifying heating mode, the refrigerant passes through the water-refrigerant heat exchanger when the detected temperature of the cooling water is not more than a predetermined temperature. Thus, the flow path switching means is controlled.

  According to the invention described in claim 5, the air conditioning control means controls the flow path switching means so that the refrigerant passes through the water-refrigerant heat exchanger when the predetermined condition is satisfied, that is, when the temperature of the cooling water is low. . Therefore, the cooling water below a predetermined temperature can be heated by the refrigerant. Thereby, even if the amount of heat of the cooling water is insufficient, the amount of heat of the cooling water for executing the dehumidifying heating mode can be ensured by heating the cooling water with the refrigerant.

Further, in the invention according to claim 6, the refrigerant state detection means detects the outside air temperature as the refrigerant state quantity,
When the air conditioning mode is the dehumidifying heating mode, the air conditioning control means allows the refrigerant to pass through the water-refrigerant heat exchanger when the detected cooling water temperature is equal to or higher than a predetermined temperature and the outside air temperature is equal to or lower than the predetermined temperature. Thus, the flow path switching means is controlled.

  According to the invention described in claim 6, it is possible to determine whether the amount of heat of the refrigerant is excessive or insufficient based on the outside air temperature.

Furthermore, in the invention according to claim 7, the refrigerant state detecting means detects the refrigerant temperature as the refrigerant state quantity,
When the air conditioning mode is the dehumidifying heating mode, the air conditioning control means allows the refrigerant to pass through the water-refrigerant heat exchanger when the detected cooling water temperature is equal to or higher than a predetermined temperature and the refrigerant temperature is equal to or lower than the predetermined temperature. Thus, the flow path switching means is controlled.

  According to the seventh aspect of the present invention, it is possible to determine whether the amount of heat of the refrigerant is excessive or insufficient based on the refrigerant temperature.

  In addition, the code | symbol in the bracket | parenthesis of each above-mentioned means is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

  Hereinafter, a plurality of embodiments for carrying out the present invention will be described with reference to the drawings. Portions corresponding to the matters described in the preceding forms in each embodiment are denoted by the same reference numerals, and overlapping description may be omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described in the preceding section. Not only the combination of the parts specifically described in each embodiment, but also the embodiments can be partially combined as long as the combination does not hinder.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram showing an overall configuration of a vehicle air conditioner 1. The vehicle air conditioner 1 is mounted on a vehicle using the engine 2 as a driving source for traveling. The vehicle air conditioner 1 includes a refrigeration cycle 3, a cooling water circuit 4, an indoor unit (not shown), and a control device (not shown). The vehicle air conditioner 1 is installed, for example, in the lower part of the instrument panel in the front part of the vehicle interior of the vehicle.

  The air conditioning case 5 constituting the indoor unit has an air inlet (not shown) on one end side, an air outlet (not shown) to the vehicle interior on the other end, and the air outlet to the air outlet. The conditioned air passage 6 for guiding the conditioned air to the side is configured. An air inlet for sucking inside and outside air is provided on one end side of the air conditioning case 5. The inside air inlet and the outside air inlet are switched and opened and closed by an inside / outside air switching door (not shown). A blower (not shown) that blows air into the air conditioning case 5 is installed adjacent to the suction port. On the other end side of the air-conditioning case 5, a plurality of air outlets communicating with the passenger compartment are formed. These air outlets are respectively switched and opened and closed by a blow mode switching door (not shown), and blow modes such as a face, bi-level, foot, and defroster are set.

  An indoor unit 7 for the refrigeration cycle 3 is provided in the air conditioning case 5 on the air downstream side of the blower. The indoor unit 7 cools the air by the low-pressure refrigerant of the refrigeration cycle 3 absorbing heat from the air. A heater core 8 of the cooling water circuit 4 is provided on the air downstream side of the indoor unit 7. The heater core 8 heats air using cooling water (hot water) as a heat source. The conditioned air whose temperature has been adjusted by the indoor unit 7 and the heater core 8 is blown into the vehicle compartment from the selected outlet.

  The cooling water circuit 4 is a circuit for cooling the engine 2 provided in the engine 2 that is a heat generating device mounted on the vehicle. The cooling water circuit 4 is provided with a radiator 9 for heat dissipation and a heater core 8 for heat dissipation. Cooling water for engine cooling circulates in the cooling water circuit 4 by a water pump (not shown). The radiator 9 is connected to the radiator-side flow path 4a of the cooling water circuit 4 and is provided for adjusting (controlling) the temperature of the cooling water to be within a predetermined temperature range (for example, 90 to 110 ° C.). The heater core 8 is connected to the heater core side flow path 4b of the cooling water circuit 4 so that the cooling water flows therethrough. The heater core 8 is a heat exchanger that heats conditioned air flowing through itself using cooling water as a heating source.

  The cooling water circuit 4 is provided with a water temperature sensor (not shown). The water temperature sensor is a cooling water temperature detecting means, and is provided at the outlet of the engine 2 and detects the temperature of the cooling water flowing through the cooling water circuit 4. The water temperature sensor provides the detected cooling water temperature information to the control device.

  The refrigeration cycle 3 includes a cycle flow in which the compressor 10, the water refrigerant heat exchanger 11, the first expansion valve 12, the outdoor unit 13, the first switching valve 14, the second expansion valve 15, the indoor unit 7, and the accumulator 16 are annular. Connected sequentially to the path 17. A first bypass flow path 18 that bypasses the indoor unit 7 and connects the outdoor unit 13 and the accumulator 16 is provided. A second switching valve 19 and a third expansion valve 20 are provided in the first bypass flow path 18. A second bypass flow path 21 that bypasses the water-refrigerant heat exchanger 11 and connects the compressor 10 and the outdoor unit 13 is provided. A third switching valve 22 is provided in the second bypass flow path 21. Carbon dioxide (CO2) is used as the refrigerant circulating in the refrigeration cycle 3, and the refrigerant is used in a state where the pressure on the high pressure side is higher than the critical pressure.

  The compressor 10 is a fluid machine that is driven by an electric motor (not shown) to compress and discharge the refrigerant to high temperature and high pressure. The compressor 10 can change the discharge amount of the refrigerant according to the operating rotational speed. The operation and the refrigerant discharge amount of the compressor 10 are controlled by the control device. On the discharge side of the compressor 10, for example, between the compressor 10 and the water-refrigerant heat exchanger 11, refrigerant state detection means for detecting the refrigerant state quantity is provided. The refrigerant state detection means is realized by a temperature sensor that detects the temperature of the discharged refrigerant and a pressure sensor that detects the pressure of the refrigerant. Each sensor gives the detected temperature information and pressure information to the control device.

  The water-refrigerant heat exchanger 11 is provided between the compressor 10 and the outdoor unit 13, a refrigerant passage through which the refrigerant discharged from the compressor 10 passes, and a cooling water passage through which the cooling water of the cooling water circuit 4 passes. And have. The water-refrigerant heat exchanger 11 performs heat exchange between the refrigerant passing through the refrigerant passage and the cooling water passing through the cooling water passage. The water-refrigerant heat exchanger 11 is a heat exchanger formed inside so that the refrigerant passage and the cooling water passage face each other.

  The first expansion valve 12 is a decompression unit that decompresses the refrigerant flowing out of the water-refrigerant heat exchanger 11 (makes it low temperature and low pressure). The first expansion valve 12 is configured such that the opening degree of the first expansion valve 12 is varied by the control device, and the amount of pressure reduction is adjusted. As the valve opening degree of the first expansion valve 12 is changed from the small side to the large side, the amount of pressure reduction of the refrigerant decreases, and the maximum valve opening degree is configured not to have a pressure reducing function.

  The outdoor unit 13 is a condenser and is a heat exchanger that exchanges heat between the refrigerant that has flowed out of the first expansion valve 12 and the outside air that flows into the engine room. The outdoor unit 13 is disposed in front of the engine room of the vehicle, for example, behind the grill. On the refrigerant outflow side of the outdoor unit 13, for example, a temperature sensor that detects the temperature of the refrigerant that flows out of the outdoor unit 13 is provided between the outdoor unit 13 and the first switching valve 14. The temperature sensor gives the detected temperature information to the control device.

  The first switching valve 14 switches between an open state in which the flow of the refrigerant flowing out of the outdoor unit 13 is guided to the second expansion valve 15 and a closed state in which the flow is blocked. The open / close state of the first switching valve 14 is controlled by the control device.

  The second expansion valve 15 is a pressure reducing means for reducing the pressure of the refrigerant flowing out of the outdoor unit 13 when the first switching valve 14 is switched to the open state (making the temperature low and low pressure). A temperature sensing unit (not shown) and a capillary (not shown) are connected to the second expansion valve 15, and the valve opening degree of the expansion valve is adjusted according to the temperature of the refrigerant flowing out of the outdoor unit 13. This is a mechanical expansion valve. Specifically, when the refrigerant temperature in the temperature sensing part is high, the valve opening is varied to the small side and the refrigerant pressure in the outdoor unit 13 is maintained on the high side, and conversely the refrigerant temperature in the temperature sensing part becomes low. The valve opening degree is changed to the larger side, and the refrigerant pressure in the outdoor unit 13 is maintained to the lower side.

  The indoor unit 7 is disposed so as to cross the entire flow path in the air conditioning case 5 of the indoor unit. The indoor unit 7 is an evaporator, and is a heat exchanger that cools the conditioned air by exchanging heat between the refrigerant decompressed by the second expansion valve 15 and the conditioned air flowing through the air conditioning case 5. . A temperature sensor (not shown) that detects the temperature of the cooled air is provided on the downstream side of the conditioned air flow in the indoor unit 7. The temperature sensor gives the detected temperature information to the control device.

  The accumulator 16 receives the refrigerant that has flowed out of the indoor unit 7, separates the gas-liquid of the refrigerant and stores the liquid refrigerant, and stores the gas refrigerant and a small amount of liquid refrigerant (oil is dissolved) near the bottom of the compressor 10. It is a receiver that inhales to the side.

  In the air conditioning case 5, in addition to the indoor unit 7, a heater core 8 as a heater is disposed. The heater core 8 is disposed downstream of the conditioned air flow with respect to the indoor unit 7. A bypass passage 23 is formed between the heater core 8 and the air conditioning case 5 so as to bypass the heater core 8 and through which conditioned air flows.

  The heater core 8 is provided with an air mix door 24 for adjusting the amount of air-conditioned air passing therethrough. The air mix door 24 is a rotary door that opens and closes the air-conditioned air circulation part of the heater core 8. In accordance with the opening degree of the air mix door 24, the flow rate ratio between the heated air flowing through the heater core 8 and the cooling air flowing through the bypass passage 23 is adjusted, and the conditioned air temperature downstream of the heater core 8 is adjusted. The opening degree of the air mix door 24 is controlled by a control device.

  Next, the first bypass channel 18 will be described. The second switching valve 19 switches between an open state that guides the flow of the refrigerant flowing out of the outdoor unit 13 to the second expansion valve 15 and a closed state that blocks the flow. The open / close state of the second switching valve 19 is controlled by the control device. The third expansion valve 20 is a decompression unit that decompresses the refrigerant flowing out of the outdoor unit 13 when the second switching valve 19 is switched to the open state. The refrigerant decompressed by the third expansion valve 20 is guided to the accumulator 16.

  Next, the second bypass flow path 21 will be described. The third switching valve 22 is a switching unit, and is in an open state in which the flow of the refrigerant discharged from the compressor 10 bypasses the water-refrigerant heat exchanger 11 and is led to the outdoor unit 13, and a closed state in which the flow is blocked. Switch over. The open / close state of the third switching valve 22 is controlled by the control device.

  The control device is air conditioning control means, and includes a microcomputer and its peripheral circuits. The control device performs arithmetic processing on information given from various sensors and setting information set by an occupant on an operation panel (not shown) according to a preset program. Further, the operation panel has a function as air conditioning mode setting means for setting any one air conditioning mode among the cooling mode, the heating mode, and the dehumidifying heating mode as the setting information. The control device determines a control mode to be described later according to the set air conditioning mode. Based on the result of the arithmetic processing in the determined control mode, the control device controls the operation of the compressor 10 and the discharge amount control, the valve opening control of the first expansion valve 12, the first to third switching valves 14, 19, The opening / closing control 22 and the opening control of the air mix door 24 are performed.

  Next, the procedure for determining the control mode of the control device will be described. FIG. 2 is a flowchart showing the procedure for setting the control mode of the control device. This flow is repeatedly executed in a short time in a state where power is supplied to the control device.

  In step a1, it is determined whether or not the air conditioning mode set by the operation panel is the cooling mode. If the air conditioning mode is the cooling mode, the process proceeds to step a2, and if not, the process proceeds to step a3. In step a2, since the set air conditioning mode is the cooling mode, the control device is set to the cooling mode, and this flow is finished.

  In step a3, it is determined whether or not the air conditioning mode set by the operation panel is the heating mode. If the air conditioning mode is the heating mode, the process proceeds to step a4. If not, the process proceeds to step a5. In step a4, since the set air conditioning mode is the heating mode, the control device is set to the heating mode, and this flow ends.

  In step a5, since the air conditioning mode set by the operation panel is neither the cooling mode nor the heating mode, it is determined that the mode is the dehumidifying heating mode, and it is determined whether the cooling water temperature is higher than the preset temperature TW. If it is higher than the temperature TW, the process moves to step a6, and if it is not higher, the process moves to step a9. In step a9, since the temperature of the cooling water is low in the dehumidifying heating mode, the control device is set to the cooling water heating mode for heating the cooling water, and this flow is finished. Such a set temperature TW of the cooling water is set based on whether or not it is a temperature at which the cooling water can be heated using the refrigerant. For example, the set temperature TW is set by comprehensively determining the type of refrigerant, the air conditioning load, the performance of the compressor 10, and the like.

  In step a6, it is determined whether the pressure of the refrigerant in the refrigeration cycle 3 and the pressure on the high pressure side discharged from the compressor 10 is greater than a preset pressure Ph. If greater than the preset pressure Ph, step a7 is performed. If not, go to step a8. In step a7, since the coolant temperature is higher than the set temperature TW and the pressure on the high pressure side of the refrigerant is higher than the set pressure Ph, it is determined that the dehumidifying heating mode can be executed, and the control device is set to the dehumidifying heating mode. Exit. In step a8, since the pressure on the high pressure side of the refrigerant is low in the dehumidifying and heating mode, the control device is set to the refrigerant heating mode for heating the refrigerant, and this flow ends.

  Such a set pressure Ph of the refrigerant is set based on whether or not it is a temperature at which the refrigerant can be heated using the cooling water. For example, the set pressure Ph is set by comprehensively judging the temperature of the cooling water, the type of refrigerant, the air conditioning load, the performance of the compressor 10, and the like.

  Next, control of each part of the control device in each control mode in which the control device is set in FIG. 2 will be described. Table 1 shows the open / closed state of the first to third switching valves 14, 19, 22 and the opening degree of the first expansion valve 12 in each control mode.

  FIGS. 3-6 is a schematic diagram which shows the whole structure of the vehicle air conditioner 1 in each control mode. 3 to 6, the refrigerant circulation path is indicated by a broken line. First, the case where the control mode is the cooling mode and the dehumidifying heating mode will be described. As shown in Table 1, the open / close state of each valve is the same in the cooling mode and the dehumidifying heating mode. FIG. 3 is a schematic diagram illustrating the overall configuration of the vehicle air conditioner 1, and is a schematic diagram illustrating a refrigerant circulation path in the cooling mode and the dehumidifying heating mode.

  As shown in Table 1 and FIG. 3, the control device opens the first switching valve 14, sets the second switching valve 19, closes the third switching valve 22, and sets the third switching valve 22 to the open state. 12 is set to a normal state in which the decompression function is exhibited, and the compressor 10 is operated. Then, since the third switching valve 22 is in the open state and the first expansion valve 12 is in the normal state, the refrigerant discharged from the compressor 10 is mainly in the second bypass due to the flow resistance by the first expansion valve 12. Flows through the channel 21. Thus, the refrigerant discharged from the compressor 10 bypasses the water / refrigerant heat exchanger 11 and the first expansion valve 12 by the second bypass flow path 21, and the compressor 10 → the third switching valve 22 → the outdoor unit 13. It circulates in order of the first switching valve 14, the second expansion valve 15, the indoor unit 7, the accumulator 16, and the compressor 10.

  Here, since the first expansion valve 12 is bypassed, the decompression function of the first expansion valve 12 is not exhibited, and the high-temperature and high-pressure refrigerant discharged from the compressor 10 dissipates heat to the outside air and is cooled by the outdoor unit 13. The cooled refrigerant is decompressed by the second expansion valve 15 whose valve opening is adjusted by the temperature sensing part and the capillary, flows into the indoor unit 7, is evaporated by the air for air conditioning, and is conditioned air by the latent heat of evaporation at that time. Cool down. The control device controls the discharge amount of the compressor 10 and the opening degree of the air mix door 24 so that the conditioned air temperature detected by the temperature sensor becomes the set temperature set by the occupant. In the dehumidifying / heating mode, the air-conditioning air temperature and the humidity are controlled to be different between the cooling mode and the dehumidifying / heating mode by controlling the opening degree of the air mix door 24 in particular.

  Next, the case where the control mode is the heating mode will be described. FIG. 4 is a schematic diagram illustrating the overall configuration of the vehicle air conditioner 1, and is a schematic diagram illustrating a refrigerant circulation path in the heating mode. As shown in Table 1 and FIG. 4, the control device closes the first switching valve 14, opens the second switching valve 19, closes the third switching valve 22, and sets the first expansion valve 12. The valve opening degree that exhibits the pressure reducing function is set, and the compressor 10 is operated. Then, since the refrigerant discharged from the compressor 10 flows through the first bypass flow path 18, the water / refrigerant heat exchanger 11 → the first expansion valve 12 → the outdoor unit 13 → the second switching valve 19 → the third expansion valve 20 → the accumulator. It circulates in order of 16-> compressor 10. Therefore, the refrigerant does not flow into the indoor unit 7.

  The high-temperature and high-pressure refrigerant discharged from the compressor 10 radiates heat to the cooling water in the cooling water circuit 4 by the water refrigerant heat exchanger 11 to heat the cooling water. Further, the heated cooling water radiates heat to the conditioned air by the heater core 8 to heat the conditioned air. The control device controls the discharge amount of the compressor 10 and the opening of the air mix door 24 to adjust the air-conditioning air temperature.

  Next, the case where the control mode is the cooling water heating mode will be described. FIG. 5 is a schematic diagram showing an overall configuration of the vehicle air conditioner 1, and is a schematic diagram showing a refrigerant circulation path in the cooling water heating mode. As shown in Table 1 and FIG. 2, the cooling water heating mode is a mode that is executed in a state where the cooling water temperature is lower than the set temperature TW and the heat source cannot be secured.

  As shown in Table 1 and FIG. 5, the control device opens the first switching valve 14, closes the second switching valve 19, closes the third switching valve 22, and sets the first expansion valve 12. The fully open position is set to a valve opening degree that does not exhibit the decompression function, and the compressor 10 is operated. Then, the refrigerant discharged from the compressor 10 is the water / refrigerant heat exchanger 11 → the first expansion valve 12 → the outdoor unit 13 → the first switching valve 14 → the second expansion valve 15 → the indoor unit 7 → the accumulator 16 → the compressor 10. It circulates in the order. Thus, the refrigerant passes through the water-refrigerant heat exchanger 11 by closing the third switching valve 22 and fully opening the first expansion valve 12.

  Therefore, the high-temperature and high-pressure refrigerant discharged from the compressor 10 radiates heat to the cooling water in the cooling water circuit 4 by the water refrigerant heat exchanger 11 to heat the cooling water. Therefore, the cooling water is heated, and the shortage of the heat source necessary for the dehumidifying heating mode can be solved. Such a cooling water heating mode is continued until the cooling water becomes equal to or higher than the set temperature TW.

  As described above, when the predetermined condition shown in FIG. 2 is satisfied, that is, when the temperature of the cooling water is low, the control device causes the first to third switching valves 14, 19, 22 and the first expansion valve 12 are controlled. Accordingly, the cooling water having a predetermined temperature or less can be heated by the refrigerant. Thus, even when the amount of heat of the cooling water is insufficient, the amount of heat of the cooling water for executing the dehumidifying heating mode can be ensured by heating the cooling water with the refrigerant.

  Next, the case where the control mode is the refrigerant heating mode will be described. FIG. 6 is a schematic diagram illustrating the overall configuration of the vehicle air conditioner 1, and is a schematic diagram illustrating a refrigerant circulation path in the refrigerant heating mode. FIG. 7 is a diagram showing the state of the refrigerant before executing the refrigerant heating mode on the Mollier diagram. As shown in Table 1 and FIG. 2, the refrigerant heating mode is a state in which the cooling water temperature is lower than the set temperature TW and the heat source is not secured, and the pressure on the high pressure side of the refrigerant is lower than the set pressure Ph. This mode is executed when there is a shortage. In the state in which the refrigerant heating mode is executed in this way (see FIG. 7), the difference between the high and low pressures of the refrigerant is small and the enthalpy is excessive, so that the necessary refrigerant cannot be flowed by the pressure reduction by the second expansion valve 15. is there.

  As shown in Table 1 and FIG. 6, the control device opens the first switching valve 14, closes the second switching valve 19, closes the third switching valve 22, and sets the first expansion valve 12. The fully open position is set to a valve opening degree that does not exhibit the decompression function, and the compressor 10 is operated. Then, the refrigerant discharged from the compressor 10 is the water / refrigerant heat exchanger 11 → the first expansion valve 12 → the outdoor unit 13 → the first switching valve 14 → the second expansion valve 15 → the indoor unit 7 → the accumulator 16 → the compressor 10. It circulates in the order. Thus, the refrigerant passes through the water-refrigerant heat exchanger 11 by closing the third switching valve 22 and fully opening the first expansion valve 12.

  Accordingly, the refrigerant discharged from the compressor 10 is heated by the cooling water in the cooling water circuit 4 in the water refrigerant heat exchanger 11. Therefore, the refrigerant is heated, and the pressure shortage necessary for the dehumidifying heating mode can be resolved. Such a refrigerant heating mode is continued until the refrigerant reaches a set pressure Ph or higher.

  As described above, when the predetermined condition shown in FIG. 2 is satisfied, that is, when the pressure on the high-pressure side of the refrigerant in the refrigeration cycle 3 is low and the cooling water can be used as a heat source that can heat the refrigerant, Controls the first to third switching valves 14, 19, 22 and the first expansion valve 12 so as to pass through the water-refrigerant heat exchanger 11. Therefore, the coolant having a predetermined pressure or lower can be heated by the cooling water having a predetermined temperature or higher. This eliminates the problem of high / low pressure difference of the refrigerant, so that the refrigerant can be circulated in the dehumidifying heating mode as shown in FIG.

  As described above, when the control mode is the dehumidifying heating mode, the vehicle air conditioner 1 according to the present embodiment uses the water-refrigerant heat exchanger 11 to meet the refrigerant condition when the predetermined condition (see FIG. 2) is satisfied. Control to exchange heat with cooling water. Thereby, for example, even when the outside air temperature is low and the high / low pressure difference of the refrigerant is small, the refrigerant can be heated with the cooling water (see FIG. 6), and the high pressure of the refrigerant can be increased. Therefore, the problem of the high / low pressure difference of the refrigerant is solved, so that the refrigerant can be circulated. Even if the amount of heat of the cooling water is insufficient, the amount of heat of the cooling water for executing the dehumidifying heating mode can be secured by heating the cooling water with the refrigerant (see FIG. 5). In this way, the control device controls the opening / closing states of the first to third switching valves 14, 19, 22 and the valve opening degree of the first expansion valve 12 (see Table 1), thereby controlling the heat of the refrigerant and water. The exchange of heat can be controlled, and the amount of heat of the medium flowing through the different flow paths can be used effectively.

  In the present embodiment, since the third switching valve 22 is provided in the second bypass flow path 21, the control device controls the third switching valve 22 to be in a closed state, as shown in FIGS. 5 and 6. In addition, the refrigerant can be circulated through the cycle channel 17. The cycle passage 17 is provided with a first expansion valve 12, and the control device controls the first expansion valve 12 so that there is no amount of pressure reduction, that is, no pressure reduction. In this case, the refrigerant can be circulated through the water-refrigerant heat exchanger 11 when the high-low pressure difference is small. If the refrigerant does not want to flow through the water-refrigerant heat exchanger 11, the third switching valve 22 is opened, and the pressure reduction amount of the first expansion valve 12 is set to a predetermined pressure reduction amount, so that water-refrigerant heat exchange is performed. The refrigerant discharged from the compressor 10 can be supplied to the outdoor unit 13 via the second bypass channel 21 without circulating the refrigerant through the unit 11. In this way, the control device controls the third switching valve 22 and the first expansion valve 12 that function as the flow path switching unit, thereby causing the water refrigerant heat exchanger 11 to circulate and not to circulate the refrigerant. Can be switched.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 8 is a schematic diagram showing the overall configuration of the vehicle air conditioner 1A of the second embodiment. The refrigeration cycle 3A of the second embodiment is characterized in that an ejector 25 is used instead of the second expansion valve 15 in the first embodiment. As shown in FIG. 8, the refrigeration cycle 3 of the present embodiment connects the compressor 10, the outdoor unit 13, the ejector 25, and the accumulator 16 in a ring shape, and the liquid phase refrigerant separated by the accumulator 16 is passed through the indoor unit 7. Then, the suction unit 26 of the ejector 25 is configured to be sucked. Therefore, the liquid-phase refrigerant outflow side of the accumulator 16 is connected to the inflow side of the indoor unit 13.

  The ejector 25 includes a nozzle 27 that decompresses and expands a high-pressure refrigerant in an isentropic manner. The ejector 25 decompresses and expands the high-pressure refrigerant from the outdoor unit 13 at the nozzle 27 to generate a high-speed refrigerant flow, circulates the low-pressure side refrigerant in the generated refrigerant flow, and converts the expansion energy into pressure energy. The suction pressure of the compressor 10 is increased by conversion.

  As shown in FIG. 8, the ejector 25 sucks the vapor phase refrigerant evaporated by converting the pressure energy of the high-pressure refrigerant into velocity energy to decompress and expand the refrigerant, and the high-speed refrigerant flow ejected from the nozzle 27. A suction unit 26, a mixing unit 28 for mixing the refrigerant injected from the nozzle 27 and the sucked gas phase refrigerant, and a diffuser for increasing the pressure of the refrigerant by converting the velocity energy of the refrigerant mixed in the mixing unit 28 into pressure energy. 29.

  In the mixing unit 28, the driving flow and the suction flow are mixed so that the sum of the momentum of the driving flow ejected from the nozzle 27 and the momentum of the suction flow sucked from the suction unit 26 is stored in the mixing unit 28. Therefore, the refrigerant pressure also increases in the mixing unit 28. In the diffuser 29, the velocity energy of the refrigerant is converted into pressure energy by gradually increasing the cross-sectional area of the passage. Therefore, in the ejector 25, the refrigerant pressure is increased by both the mixing unit 28 and the diffuser 29.

  Next, the operation of the ejector 25 will be described. The ejector 25 functions in a control mode in which the refrigerant passes through the ejector 25, in other words, a control mode other than the heating mode. When the ejector 25 functions, the refrigerant discharged from the compressor 10 flows into the nozzle 27 through the outdoor unit 13 and the first switching valve 14. The refrigerant cooled and condensed in the outdoor unit 13 is decompressed and expanded by the nozzle 27 of the ejector 25 and sucks the refrigerant in the indoor unit 7. The refrigerant sucked from the indoor unit 7 and the refrigerant blown out from the nozzle 27 are mixed by the mixing unit 28, the dynamic pressure thereof is converted into a static pressure by the diffuser 29, and returned to the accumulator 16. As a result, the suction pressure of the compressor 10 increases. Therefore, the discharge pressure of the compressor 10 increases. Further, since the refrigerant in the indoor unit 7 is sucked by the ejector 25, the liquid phase refrigerant flows into the indoor unit 7 from the accumulator 16, and the refrigerant that has flowed in absorbs heat from the air blown into the room and evaporates.

  Even in the refrigeration cycle 3 having such an ejector 25, when the control device satisfies a predetermined condition as in the first embodiment, the first embodiment is performed by executing the cooling water heating mode and the refrigerant heating mode. Actions and effects similar to those of the form can be achieved.

(Other embodiments)
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  In each of the above-described embodiments, the pressure on the high pressure side of the refrigerant is used as the detected refrigerant state quantity to determine whether there is a pressure shortage. However, the refrigerant state quantity is limited to the pressure on the high pressure side of the refrigerant. For example, the outside air temperature may be detected as the state quantity of the refrigerant. Whether or not the refrigerant pressure is insufficient can be determined based on the outside air temperature. In such a case, when the air-conditioning mode is the dehumidifying heating mode, the control device, when the detected coolant temperature is equal to or higher than the predetermined temperature and the outside air temperature is equal to or lower than the predetermined temperature, the water-refrigerant heat exchanger 11 The flow path switching means is controlled so that the refrigerant passes through. As a result, the same operations and effects as those of the above-described embodiments can be achieved.

  Further, as the refrigerant state quantity, for example, the refrigerant temperature may be detected. The refrigerant temperature is, for example, the temperature of the refrigerant between the compressor 10 and the outdoor unit 13. Whether or not the refrigerant pressure is insufficient can be determined based on the detected refrigerant temperature. In such a case, when the air conditioning mode is the dehumidifying and heating mode, the control device, when the detected coolant temperature is equal to or higher than the predetermined temperature and the refrigerant temperature is equal to or lower than the predetermined temperature, the water / refrigerant heat exchanger 11 The flow path switching means is controlled so that the refrigerant passes through. As a result, the same operations and effects as those of the above-described embodiments can be achieved. As a result, the same operations and effects as those of the above-described embodiments can be achieved.

  In each of the above-described embodiments, the flow path switching means is realized by the second bypass flow path 21, the third switching valve 22, and the first expansion valve 12, but is not limited thereto. The flow path switching means includes a flow path in which the refrigerant discharged from the compressor 10 passes through the refrigerant passage of the water-refrigerant heat exchanger 11 and flows to the outdoor unit 13, and the refrigerant discharged from the compressor 10 passes through the refrigerant passage. What is necessary is just a structure which switches the flow path which flows into the outdoor unit 13 without making it. For example, the first switching valve 12 shown in FIG. 1 has a fixed opening, and the third switching channel that bypasses the first expansion valve 12 and the fourth switching that is provided in the third bypass channel. It may be realized by a valve. Even if it is the 1st expansion valve 12 by which the opening degree is fixed by this, by opening a 4th switching valve, the opening degree of the 1st expansion valve 12 is demonstrated as demonstrated in 1st Embodiment. Actions and effects similar to those when maximized can be achieved.

  In each of the above-described embodiments, the air conditioning mode is only the cooling mode, the heating mode, and the dehumidifying heating mode. However, other air conditioning modes such as the dehumidifying cooling mode and the dehumidifying mode can be selected. Also good.

  In each of the above-described embodiments, the refrigerant used in the refrigeration cycle 3 is carbon dioxide. However, the refrigerant is not limited to carbon dioxide, and a fluorocarbon refrigerant may be used. Further, the heater core 8 has been described as having the cooling water circulated from the engine 2 as a heat source. However, the present invention is not limited to this, and the cooling water from the fuel cell in the fuel cell vehicle may be used as a heat source as a heat generating device.

It is a schematic diagram which shows the whole structure of the vehicle air conditioner 1 of 1st Embodiment. It is a flowchart which shows the setting procedure of the control mode of a control apparatus. It is a schematic diagram which shows the circulation path | route of the refrigerant | coolant in air_conditioning | cooling mode and dehumidification heating mode. It is a schematic diagram which shows the circulation path | route of the refrigerant | coolant in heating mode. It is a schematic diagram which shows the circulation path | route of the refrigerant | coolant in a cooling water heating mode. It is a schematic diagram which shows the circulation path | route of the refrigerant | coolant in refrigerant | coolant heating mode. It is the figure which showed the state of the refrigerant | coolant before performing refrigerant | coolant heating mode on the Mollier diagram. It is a schematic diagram which shows the whole structure of 1 A of vehicle air conditioners of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Refrigeration cycle 4 ... Cooling water circuit 4a ... Radiator side flow path 4b ... Heater core side flow path 5 ... Air-conditioning air path 7 ... Indoor unit (evaporator)
DESCRIPTION OF SYMBOLS 8 ... Heater core 10 ... Compressor 11 ... Water refrigerant | coolant heat exchanger 12 ... 1st expansion valve (pressure reduction part)
13 ... Outdoor unit (condenser)
15 ... Second expansion valve (pressure reducing means)
17 ... Cycle channel 21 ... Second bypass channel (detour channel)
22 ... 3rd switching valve (switching part)
25 ... Ejector 27 ... Nozzle

Claims (7)

A vehicle air conditioner that provides conditioned air into the passenger compartment using a cooling water circuit (4) and a refrigeration cycle (3),
An air-conditioning air passage (5) having an air intake port on one end side and an air outlet to the vehicle interior on the other end side;
A blower for blowing air from the inlet side to the outlet side;
A cooling water circuit (4) through which cooling water for cooling a heat generating device mounted on the vehicle circulates;
A compressor (10) that compresses and discharges the refrigerant to a high temperature and a high pressure, a condenser (13) that condenses the refrigerant discharged from the compressor by exchanging heat with the outside air, and a refrigerant condensed in the condenser A refrigerating cycle (15) including a depressurizing means (15) for depressurization, an evaporator (7) installed in the conditioned air passage, and absorbing and evaporating the refrigerant depressurized by the depressurizing means by absorbing heat from the air 3) and
A refrigerant provided between the compressor and the condenser, having a refrigerant passage through which the refrigerant discharged from the compressor passes, and a cooling water passage through which the cooling water passes, and passing through the refrigerant passage; A water refrigerant heat exchanger (11) for exchanging heat with cooling water passing through the cooling water passage;
A heater core (8) provided in the cooling water circuit, installed on the downstream side of the evaporator in the conditioned air passage, and heats the air by exchanging heat with the cooling water;
Cooling water temperature detecting means for detecting the temperature of the cooling water;
Refrigerant state detecting means for detecting a state quantity of the refrigerant;
Air-conditioning mode setting means for setting each air-conditioning mode of cooling mode, heating mode and dehumidifying heating mode;
Air conditioning control means for controlling the flow path switching means based on the air conditioning mode set by the air conditioning mode setting means,
In the refrigeration cycle, the refrigerant discharged from the compressor passes through the refrigerant passage and flows to the condenser, and the refrigerant discharged from the compressor passes through the refrigerant passage without passing through the refrigerant passage. Including flow path switching means (12, 21, 22) for switching between the flow path to flow through
When the air conditioning mode is the dehumidifying heating mode, the air conditioning control means determines the cooling water for executing the dehumidifying heating mode based on the detected temperature of the cooling water and the state quantity of the refrigerant. When the amount of heat is insufficient, or when the pressure of the refrigerant for executing the dehumidifying and heating mode is low, the flow path switching means is set so that the refrigerant passes through the refrigerant passage of the water refrigerant heat exchanger. A vehicle air conditioner that is controlled.   The decompression means has a nozzle (27) that decompresses and expands a high-pressure refrigerant in an isentropic manner, and generates a high-speed refrigerant flow by decompressing and expanding the high-pressure refrigerant at the nozzle. 2. The vehicle air conditioner according to claim 1, wherein the vehicle air conditioner is an ejector (25) that circulates a low-pressure side refrigerant and converts expansion energy into pressure energy to increase the suction pressure of the compressor. 3. The flow path switching means is
A bypass channel (21) in which the refrigerant discharged from the compressor bypasses the water-refrigerant heat exchanger and reaches the condenser;
A switching unit (22) that is provided in the bypass channel and switches between open and closed states of the bypass channel;
The refrigerant discharged from the compressor passes through the water-refrigerant heat exchanger and reaches the condenser, the cycle flow path (17);
The pressure reducing part (12) provided between the water refrigerant heat exchanger and the condenser in the cycle flow path, wherein the pressure reducing amount of the refrigerant passing therethrough is variable. The vehicle air conditioner according to 2. The refrigerant state detection means detects the refrigerant pressure on the high pressure side of the refrigeration cycle as a refrigerant state quantity,
When the air conditioning mode is the dehumidifying heating mode, the air conditioning control means is configured such that when the detected temperature of the cooling water is equal to or higher than a predetermined temperature and the pressure of the refrigerant is equal to or lower than the predetermined pressure, the water / refrigerant heat exchanger The vehicle air conditioner according to any one of claims 1 to 3, wherein the flow path switching unit is controlled such that the refrigerant passes through the vehicle.   When the air conditioning mode is the dehumidifying heating mode, the air conditioning control unit is configured to switch the flow path so that the refrigerant passes through the water-refrigerant heat exchanger when the detected temperature of the cooling water is equal to or lower than a predetermined temperature. The vehicle air conditioner according to any one of claims 1 to 4, wherein the vehicle air conditioner is controlled. The refrigerant state detection means detects the outside air temperature as a refrigerant state quantity,
When the air conditioning mode is the dehumidifying and heating mode, the air conditioning control unit controls the water refrigerant heat exchanger when the detected cooling water temperature is equal to or higher than a predetermined temperature and the outside air temperature is equal to or lower than the predetermined temperature. The vehicle air conditioner according to any one of claims 1 to 3, wherein the flow path switching unit is controlled so that a refrigerant passes therethrough. The refrigerant state detecting means detects a refrigerant temperature as a refrigerant state quantity,
When the air conditioning mode is the dehumidifying and heating mode, the air conditioning control means controls the water / refrigerant heat exchanger when the detected coolant temperature is equal to or higher than a predetermined temperature and the refrigerant temperature is equal to or lower than the predetermined temperature. The vehicle air conditioner according to any one of claims 1 to 3, wherein the flow path switching unit is controlled so that a refrigerant passes therethrough.

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