JP4055739B2 - Air conditioner for vehicles - Google Patents

Description

  The present invention relates to a vehicle air conditioner mounted on a vehicle driven by a prime mover, for example, an engine or a fuel cell.

Conventionally, as described in Patent Document 1, in the winter, the fuel cell heat exchanger is heated by the vehicle air conditioning heat pump unit, or the fuel cell cooling water is indirectly heated, and the fuel cell cooling water is heated. There are vehicle air conditioners whose main purpose is to prevent freezing.
JP 2001-167777 A

  However, although Patent Document 1 described above describes that heat is transferred (released) from the vehicle air conditioning heat pump unit to the fuel cell cooling circuit, this is intended to prevent freezing of the fuel cell cooling water in winter. For this reason, nothing is described about the cooling of the passenger compartment in the summer.

  Moreover, the vehicle air conditioner described in Patent Document 1 described above is premised on a fuel cell vehicle and does not describe application to an engine vehicle.

  In view of the above points, the present invention is applicable not only to fuel cell vehicles but also to engine vehicles, and can be applied not only to heating in a vehicle interior in winter but also to cooling a vehicle interior in summer, from a heat pump unit to a motor. An object of the present invention is to provide a vehicle air conditioner that can increase the efficiency of air conditioning in a passenger compartment by transferring (releasing) heat to a cooling circuit.

  In order to achieve the above object, the present invention employs the following technical means.

In the vehicle air conditioner according to claim 1, the prime mover cooling water that has received the heat generated from the prime mover flows to the heater core side for heat dissipation and returns to the prime mover, and flows to the radiator side for heat radiation. A prime mover cooling water circuit having a radiator side flow path returning to the prime mover;
During the cooling operation, the refrigerant is compressed by the compressor, the refrigerant is condensed by the second heat exchanger, the interior of the vehicle is cooled by the indoor heat exchanger,
During heating operation, the flow direction of the refrigerant is changed by the four-way valves arranged on the suction side and discharge side of the compressor, the heat is absorbed by the second heat exchanger, and the vehicle interior is heated by the indoor heat exchanger. A vehicle air conditioner comprising a heat pump unit,
On the discharge side of the compressor, a first heat exchanger is provided between the compressor and the four-way valve, and discharges the heat of the refrigerant compressed by the compressor to the motor coolant in the heater core side flow path .
The radiator side flow path is provided with a bypass flow path in which the prime mover cooling water bypasses the radiator, and a valve for adjusting the flow of the prime mover cooling water to the radiator side or the bypass flow path based on the temperature of the prime mover cooling water. ,
During the cooling operation of the heat pump unit and when the prime mover cooling water is equal to or higher than the first temperature threshold, the prime mover cooling water flows into the radiator side,
During heating operation of the heat pump and when the water temperature of the prime mover cooling water is equal to or higher than the second temperature threshold value higher than the first temperature threshold value, the prime mover cooling water flows into the radiator side. .

  According to the present invention, during the cooling operation, the prime mover cooling water is allowed to flow through the radiator at the first lower temperature threshold value, so that the prime mover cooling water is around the first lower temperature threshold value. Since the refrigerant will be able to dissipate (release) a large amount of heat in the first heat exchanger against the prime mover cooling water that changes at this low temperature, the heat pump unit The heat dissipation increases, and the air conditioning efficiency in the passenger compartment can be increased.

The vehicle air conditioner according to claim 2 is provided between the second heat exchanger and the indoor heat exchanger during cooling operation of the heat pump unit .
A third heat exchanger for exchanging heat between the high-temperature and high-pressure refrigerant discharged from the second heat exchanger and the low-temperature and low-pressure refrigerant discharged from the indoor heat exchanger is provided.

  According to the present invention, the refrigerant before flowing into the indoor heat exchanger can be dissipated in the third heat exchanger, so that the efficiency of the air conditioner can be further increased.

Air-conditioning system according to claim 3, the flow direction of the high-temperature high-pressure refrigerant flowing in the third heat exchanger, it is set to be in counterflow to the flow direction of the low-temperature and low-pressure refrigerant It is characterized by.

  According to the present invention, the heat exchange rate between the high-temperature and high-pressure refrigerant and the low-temperature and low-pressure refrigerant in the third heat exchanger can be further increased.

The vehicle air conditioner according to claim 4 has another cooling water circuit in which cooling water lower than the temperature of the motor cooling water flowing through the motor cooling water circuit flows .
Between the first heat exchanger and the second heat exchanger during the cooling operation of the heat pump unit ,
A fourth heat exchanger is provided that discharges the heat of the high-temperature and high-pressure refrigerant discharged from the first heat exchanger to the cooling water of another cooling water circuit .

  In vehicles, there is a system including a cooling circuit in addition to a prime mover. For example, if this vehicle is a hybrid vehicle, there is a drive motor. If this vehicle is an engine vehicle, it is a water-cooled intercooler or the like.

Among the cooling circuits other than the prime mover cooling circuit, the refrigerant that circulates in the heat pump unit with respect to the cooling water in the cooling circuit that circulates at a lower temperature than the prime mover cooling water that circulates in the prime mover cooling circuit. By providing the fourth heat exchanger capable of releasing the amount of heat, it becomes possible to increase the air conditioning efficiency during cooling.
In the vehicle air conditioner according to claim 5 , the other cooling water circuit includes a second radiator for cooling the cooling water flowing through the other cooling water circuit, and the second radiator, The heat exchanger is characterized in that it is arranged on the upstream side of the air flow of the radiator.

  According to the present invention, the radiator, the second radiator, and the second heat exchanger can efficiently release heat to the outside air.

The refrigerant in the vehicle air conditioner according to claim 6 is CO ₂ .

  There are various types of refrigerants used in heat pump units (refrigeration cycles) for air conditioning vehicles. The refrigerant that is currently mainstream is HFC134a.

However, since the CO ₂ refrigerant operates in a supercritical state than the HFC 134a refrigerant, the temperature immediately after being discharged from the compressor tends to be high (about 100 ° C.).

  In the first heat exchanger, naturally, the heat exchange between the high-temperature refrigerant and the prime mover cooling water increases the temperature difference between the two, so the heat transfer (release) efficiency is also improved. Further improvement is possible.

  Embodiments of the present invention will be described below with reference to FIGS.

(Constitution)
FIG. 1 is a configuration diagram of a vehicle air conditioner 100 according to the present invention. The vehicle air conditioner 100 includes a stack 1 cooling circuit 10 and a heat pump circuit 20.

  The stack 1 cooling circuit 10 includes a stack 1, a heater core 2, a first heat exchanger 3, a thermostat 4, a radiator 5, and a pump 6.

  The stack 1, the heater core 2, the first heat exchanger 3, the thermostat 4, the radiator 5, and the pump 6 are connected to each other by a cooling water flow path 7. The cooling water flow path 7 includes a heater core 2 side flow path 7a and a radiator 5 side flow path 7b.

  The stack 1 is a stack of single cells for power generation. In the stack 1, hydrogen and oxygen undergo a chemical reaction to generate water.

  During this process, heat is generated and the stack 1 itself generates heat. Therefore, in order to cool the stack 1, a water jacket or the like (not shown) is attached to the stack 1, and the heat generated by the chemical reaction is absorbed by the cooling water flowing through the water jacket. The downstream side of the water jacket is branched into a heater core 2 side flow path 7a and a radiator 5 side flow path 7b.

  The heater core 2 is a well-known heating heat exchanger for exchanging heat between the cooling water received from the stack 1 flowing from the heater core 2 side passage 7a and the air in the passenger compartment. The cooling water received from the stack 1 dissipates heat to the air in the passenger compartment by the heater core 2. A first heat exchanger 3 is provided downstream of the heater core 2 in the cooling water.

  The first heat exchanger 3 includes a high-temperature and high-pressure refrigerant discharged from a compressor 21 constituting a heat pump circuit 20 to be described later, and a cooling water that releases heat into the vehicle interior by the heater core 2 and has become a low temperature. Is a refrigerant-cooling water heat exchanger for exchanging heat. The first heat exchanger 3 is provided on the downstream side of the heater core 2.

  An example of the schematic structure of the first heat exchanger 3 is shown in FIG. The first heat exchanger 3 is configured such that the refrigerant flow path 3a and the cooling water flow path 3b are stacked, and is configured to be able to radiate the heat quantity of the refrigerant to the cooling water.

  The thermostat 4 is a device that is provided on the radiator 5 side flow path 7b side and adjusts the flow of the coolant to the radiator 5 based on the coolant temperature.

  The thermostat 4 includes a water temperature sensor 4a and an opening / closing valve 4b. If the coolant temperature detected by the water temperature sensor 4a is equal to or higher than a predetermined water temperature, the opening / closing valve 4b is opened to cool the cooling water. Cooling water flows into the radiator 5.

  The thermostat 4 includes a plurality of temperature thresholds at which the on-off valve 4b opens and closes. The predetermined temperature mentioned above is this temperature threshold value.

  The thermostat 4 changes the temperature threshold value for opening and closing the on-off valve 4b according to the operation type of the heat pump circuit 20 described later.

  For example, when the operation type of the heat pump circuit 20 is the cooling operation, the setting is autonomously changed so that the valve is opened at a relatively low first temperature threshold, and the coolant temperature detected by the water temperature sensor 4a is the first. When the temperature threshold is exceeded, the on-off valve 4b is opened, and the cooling water flows into the radiator 5.

  Similarly, when the operation type of the heat pump circuit 20 is the heating operation, the setting is autonomously changed so that the valve is opened at a relatively high second temperature threshold, and the coolant temperature detected by the water temperature sensor 4a is When the temperature becomes equal to or higher than the second temperature threshold value, the on-off valve 4b is opened and the cooling water is operated to flow into the radiator 5. The thermostat 4 corresponds to a valve as set forth in the claims.

  The pump 5 is a pressure feeding means provided on the flow path where the heater core 2 flow path 7a and the radiator 5 flow path 7b merge. Cooling water flowing through the heater core 2 side flow path 7 a and the radiator 5 side flow path 7 b is sent to the water jacket of the stack 1.

  Next, the configuration of the heat pump circuit 20 will be described below.

  The heat pump circuit 20 includes a compressor 21, a first heat exchanger 3, a first expansion valve 22, a four-way valve 23, a second heat exchanger 24, a third heat exchanger 25, It consists of a second expansion valve 26, an indoor heat exchanger 27, and an accumulator 28.

  The compressor 21, the first heat exchanger 3, the first expansion valve 22, the four-way valve 23, the second heat exchanger 24, the third heat exchanger 25, and the second expansion The valve 26, the indoor heat exchanger 27, and the accumulator 28 are connected by a refrigerant flow path 29.

  The compressor 21 is a well-known compression unit that compresses the refrigerant to a high temperature and a high pressure.

  Since the first heat exchanger 3 has been described above, it will be omitted, but it should be understood that the refrigerant channel 29 is connected to the refrigerant channel 3a constituting the first heat exchanger 3 so that the refrigerant can flow therethrough.

  The first expansion valve 22 is a known expansion valve that is decompressed and expanded by injecting high-temperature and high-pressure refrigerant discharged from the compressor 21 through a small hole to form a low-temperature and low-pressure mist-like gas refrigerant.

  The four-way valve 23 is a valve that changes the flow direction of the refrigerant depending on whether the operation type of the heat pump circuit 20 is set to the cooling operation or the heating operation.

  The second heat exchanger 24 is a well-known air-cooled heat exchanger that exchanges heat between air outside the passenger compartment (vehicle speed wind) and the refrigerant.

  The third heat exchanger 25 is a refrigerant-refrigerant heat exchanger that exchanges heat between the refrigerant discharged from the second heat exchanger 24 and the refrigerant flowing out from the accumulator 28 described later.

  Since the second expansion valve 26 has the same configuration as the first expansion valve 22, the description thereof is omitted.

  The indoor heat exchanger 27 is a well-known air-cooled heat exchanger that exchanges heat between the air in the passenger compartment and the refrigerant.

  The accumulator 28 is gas-liquid separation means for separating the refrigerant into gas and liquid.

(Operation)
The operation for increasing the air-conditioner efficiency in the vehicle interior by transferring (releasing) heat from the heat pump circuit 20 to the stack 1 cooling circuit 10 not only in vehicle interior heating in winter but also in vehicle interior cooling in summer will be described below. To do.

(During cooling operation)
First, the flow sequence of the refrigerant when the operation type of the heat pump circuit 20 is the cooling operation will be described below.

  The refrigerant that has been compressed by the compressor 21 to a high temperature and high pressure flows into the first heat exchanger 3.

  In the first heat exchanger 3, since the operation type of the heat pump circuit 20 is the cooling operation, low-temperature cooling water that flows around a relatively low first temperature threshold is circulated due to heat dissipation in the radiator 5. The high-pressure refrigerant releases heat to the low-temperature cooling water.

  The refrigerant that has released the amount of heat in the first heat exchanger 3 passes through the first expansion valve 22 that is controlled to be fully opened, and flows into the second heat exchanger 24 by switching the four-way valve 23.

  The refrigerant flowing into the second heat exchanger 24 exchanges heat with the air outside the passenger compartment (vehicle speed wind), and again releases heat.

  The refrigerant that has released the amount of heat again in the second heat exchanger 24 exchanges heat with air in the vehicle interior in the indoor heat exchanger 27 in the third heat exchanger 25, becomes low pressure and low temperature, and the accumulator 28. Heat exchange with the low-temperature and low-pressure refrigerant separated in gas and liquid.

  The refrigerant that has released the amount of heat again in the third heat exchanger 25 is atomized by the throttle of the second expansion valve 26, becomes a low-temperature and low-pressure gaseous refrigerant, and flows into the indoor heat exchanger 27.

  The refrigerant that has exchanged heat with the air in the passenger compartment in the indoor heat exchanger 27 returns to the four-way valve 23 again and flows into the accumulator 28 by switching the four-way valve 23.

  The accumulator 28 separates the gas and liquid, and the third heat exchanger 25 receives heat from the high-temperature and high-pressure refrigerant discharged from the second heat exchanger 24.

  The refrigerant that has passed through the third heat exchanger 25 is compressed again by the compressor 21, becomes a high-temperature and high-pressure refrigerant, is discharged from the compressor 21 again, and the following cycle is repeated.

  As described above, in the case of a normal refrigeration cycle, there is often only one radiator, but in the present embodiment, the first heat exchanger 3 (heat radiation to the cooling water) and the second heat exchanger 24 ( Heat radiation to the air outside the passenger compartment), the third heat exchanger 25 (heat radiation to the low-temperature and low-pressure refrigerant), and three heat radiators, so compared with a refrigeration cycle in which only one heat radiator is provided Therefore, the heat dissipation rate is high, and the efficiency of the air conditioner increases.

  The operation of the thermostat 4 that maintains the temperature of the cooling water flowing through the stack 1 cooling circuit 10 around the first temperature threshold value that is relatively low depending on the operation type (in this case, cooling operation) will be described below. .

  The cooling water that has received heat from the high-temperature and high-pressure refrigerant in the first heat exchanger 3 receives heat from the stack 1 (water jacket attached to the stack 1) and is discharged, and the heater core 2 side flow path 7a. To the radiator 5 side flow path 7b.

  The cooling water that has flowed into the heater core 2 side flow path 7a flows into the heater core 2 and exchanges heat with the air in the passenger compartment, resulting in a low temperature.

  Then, it flows into the 3rd heat exchanger 3, heat-exchanges with the high temperature / pressure refrigerant | coolant after being discharged from the compressor 21, and receives heat quantity. The cooling water that has received a quantity of heat from the refrigerant and has become somewhat hot returns to the pump 6.

  On the other hand, the temperature of the cooling water detected by the water temperature sensor 4a constituting the thermostat 4 is relatively low because the thermostat 4 is set independently by the first temperature threshold (in this case, the operation type of the heat pump circuit 20 is the cooling operation). If the temperature is equal to or higher than the first temperature threshold value, the thermostat 4 opens the on-off valve 4b and allows the cooling water flowing into the radiator 5 side flow path 7b to flow into the radiator 5.

  Heat is exchanged with the air outside the passenger compartment in the radiator 5 and the low-temperature cooling water is received by the first heat exchanger 3 immediately before the pump 6 and mixed with the high-temperature cooling water. The water temperature of the entire cooling water flowing through the circuit 10 is maintained so as to change around the first temperature threshold.

  The opening / closing operation of the thermostat 4 at this time will be described in detail below with reference to FIG.

  FIG. 3 consists of FIG. 3A and FIG. 3B, and the opening / closing operation of the thermostat 4 during the cooling operation is shown in FIG.

  As shown in FIG. 3A, the thermostat 4 is opened when the temperature of the cooling water becomes α ° C. or higher during the cooling operation, and the cooling water falls from α ° C. to a predetermined temperature range (for example, about 10 ° C.) or less. The valve closes when

  The reason why the temperature when opening the valve (in this case α ° C.) and the temperature when closing the valve (in this case α-10 ° C.) will be described below.

  If the temperature at which the valve is opened (in this case, α ° C.) and the temperature at which the valve is closed (in this case, α−10 ° C.) are set as the same temperature threshold, the water temperature will be α ° C. many times. Since the thermostat 4 frequently repeats the opening / closing operation of the on-off valve 4b, the setting is prevented. Incidentally, this α ° C. corresponds to the first temperature threshold value shown in the claims. Specifically, it has been found by the inventors' research that a desirable value is around 50 degrees Celsius.

(During heating operation)
Next, the flow sequence of the refrigerant when the operation type of the heat pump circuit 20 is the heating operation will be described below.

  The refrigerant compressed by the compressor 21 and having a high temperature and high pressure flows into the first heat exchanger 3.

  In the first heat exchanger 3, the amount of heat is released by the heater core 2, and the cooling water having a low temperature is circulating. Therefore, the high-temperature and high-pressure refrigerant releases the amount of heat to the low-temperature cooling water.

  The refrigerant that has released the amount of heat in the first heat exchanger 3 passes through the first expansion valve 22 that is controlled to be fully opened, and flows into the indoor heat exchanger 27 by switching the four-way valve 23.

  Although the heat is dissipated in the first heat exchanger 3, the high-temperature and high-pressure refrigerant still exchanges heat (in this case, heating) with the air in the vehicle interior in the indoor heat exchanger 27.

  The refrigerant discharged from the indoor heat exchanger 27 is atomized by the second expansion valve throttled at a predetermined opening, and flows into the third heat exchanger 25.

  In the cooling operation described above, the refrigerant also exchanges heat in the third heat exchanger 25, but in the heating operation, since the temperature difference is small, heat exchange is not performed, and the refrigerant passes therethrough. Then, the refrigerant flows into the second heat exchanger 24, where it evaporates and becomes a gaseous refrigerant and flows into the four-way valve 23.

  With the switching setting of the four-way valve 23, the refrigerant flowing into the accumulator 28 is gas-liquid separated here, flows into the compressor 21 again, is compressed again with the compressor 21, becomes a high-temperature / high-pressure refrigerant, and is discharged again from the compressor 21. The following repeats the cycle described above.

  Next, the operation of the stack 1 cooling circuit 10 during the heating operation will be described below with reference to FIG.

  Although the flow order of the cooling water during the heating operation is the same as that during the cooling operation, it will not be described in detail. However, the temperature threshold value set by the thermostat 4 autonomously is higher than the above α ° C. because the operation type of the heat pump circuit 20 is during the heating operation. Is also set to a high β ° C. (second temperature threshold).

  As shown in FIG. 3 (b), the thermostat 4 opens the on-off valve 4b when the temperature of the cooling water becomes β ° C. or higher during the heating operation, and the cooling water reaches a predetermined temperature range (for example, about 10 ° C. from β ° C.). ) Close the valve when

  The reason why the temperature at which the valve is opened (in this case β ° C.) and the temperature at which the valve is closed (in this case β-10 ° C.) is the same as that during cooling operation, and will not be described.

  During the heating operation, the cooling water temperature is set to change at a temperature threshold (β ° C.) higher than the cooling water temperature threshold (α ° C.) during the cooling operation.

The reason is that the temperature of the hot water circuit which is the (main) heating circuit is not lowered.
Therefore, the thermostat 4 has an on-off valve 4b so that the cooling water does not flow through the radiator 5 until the cooling water becomes equal to or higher than the required cooling temperature of the stack 1 β ° C. (second temperature threshold indicated in the claims). Operates to close.

(During dehumidifying heating operation)
At the time of dehumidification heating, it is divided roughly into two patterns. That is, there are two patterns: a pattern with a relatively low air conditioning load and a low required blowing temperature, and a pattern with a relatively high air conditioning load and a high required blowing temperature. Hereinafter, the refrigerant flow order and the opening / closing operation of the thermostat 4 in the two patterns will be described.
(1) Dehumidifying heating when the air conditioning load is relatively low and the required blowing temperature is low The description will be omitted because the refrigerant flow sequence in this mode is the same as that in the cooling operation described above. But there is only one difference. In the cooling operation, the first expansion valve 22 is fully opened, but in this mode, the first expansion valve 22 is narrowed to a predetermined width.

  The reason why it is narrowed down is explained below. This mode is dehumidifying heating when the air conditioning load is relatively low and the required blowing temperature is low. When the first expansion valve 22 is throttled, the refrigerant flowing into the second heat exchanger 24 has a low pressure, so that the second heat exchanger 4 operates as a heat absorber.

That is, the amount of heat Q1 generated in the compressor 21 and the amount of heat Q2 absorbed by the second heat exchanger 24 are dissipated to the cooling water by the first heat exchanger 3, so that the cooling water is predetermined by the heater core 2. It is possible to obtain the blowout temperature (lower than that in the dehumidification heating operation when the air-conditioning load is relatively high and the necessary blowout temperature is high, which will be described later).
(2) Dehumidifying heating when air conditioning load is relatively high and required blowing temperature is high The refrigerant flow sequence in this mode is the same as that in the heating operation described above, and the description thereof is omitted. But there is only one difference. In the heating mode, the first expansion valve 22 is fully opened. In this mode, the first expansion valve 22 and the second expansion valve 26 are throttled by a predetermined width.

  The reason why it is narrowed down is explained below. This mode is dehumidifying heating when the air conditioning load is relatively high and the required blowing temperature is high.

  First, when the first expansion valve 22 is throttled, the refrigerant flowing into the indoor heat exchanger 27 has a low pressure, so that the indoor heat exchanger 27 operates as a heat absorber.

  Further, by restricting the second expansion valve 26 as well, the refrigerant flowing into the second heat exchanger 24 also becomes a low pressure, and the second heat exchanger 24 also operates as a heat absorber.

  That is, the refrigerant cools the amount of heat Q1 generated by the compressor 21, the amount of heat Q2 absorbed by the second heat exchanger 24, and the amount of heat Q3 absorbed by the indoor heat exchanger 27 by the first heat exchanger 3. Since the heat is dissipated to the water, the cooling water obtains a predetermined blowing temperature at the heater core 2 (higher than that during the dehumidification heating operation when the air conditioning load is relatively low and the necessary blowing temperature is low as described above). Is possible.

  Next, the opening / closing operation | movement of the thermostat 4 mentioned above is demonstrated below using FIG.

  FIG. 4 is a flowchart showing a flow of opening and closing operation of the thermostat 4.

  In step S1, the driver performs an operation of determining a driving type from a sensor or panel (not shown). When the operation ends, the process proceeds to step S2.

  In step S2, the operation type is determined based on information from the sensor or the panel. If determined, the process proceeds to step S3.

  In step S3, it is determined whether or not the operation type determined in step S2 is a cooling operation. If it is a cooling operation, the process proceeds to step S4, and if it is not a cooling operation, the process proceeds to step S5.

  In step S4, the temperature threshold value of the opening / closing operation of the thermostat 4 is set to α ° C. (about 50 ° C.). When the setting is completed, the process proceeds to step S6.

  In step S5, the temperature threshold of the opening / closing operation of the thermostat 4 is set to β ° C. (about 80 ° C.). When the setting is completed, the process proceeds to step S6.

  If the coolant temperature near the entrance of the heater core 2 is α ° C. (about 50 ° C.) or β ° C. (about 80 ° C.) or higher in step S6, the process proceeds to step S7. If the water temperature of the cooling water is less than α ° C. (about 50 ° C.) or less than β ° C. (about 80 ° C.), the process returns to step S1.

  In step S7, the on-off valve 4b is opened. When the valve is completely opened, the process returns to step S1.

  The thermostat 4 operates to open and close at two temperature thresholds according to the operation type according to the processing contents from step S1 to step S7 described above.

(Function and effect)
With the above-described configuration and operation, heat is transferred from the refrigerant of the heat pump circuit 20 to the cooling water flow path 7 via the first heat exchanger 3 not only in the vehicle interior heating in winter but also in the vehicle interior cooling in summer ( Therefore, it is possible to provide the vehicle air conditioner 100 capable of improving the air conditioner performance that tends to be lowered during the cooling operation.

  In general, since the amount of heat released from the stack 1 decreases at low vehicle speeds or when the vehicle is stopped, there is a margin in the heat dissipation performance of the radiator 5.

  However, since the vehicle speed wind is low when the vehicle speed is low or when the vehicle is stopped, the second heat exchanger 24 is cooled only by an electric fan (not shown), so that the air conditioner performance is deteriorated.

  Therefore, during cooling operation as in the present invention, if the temperature of the cooling water flowing through the radiator 5 is controlled to be low (approximately 50 ° C.), the amount of heat released from the stack 1 is reduced at low vehicle speeds or when the vehicle is stopped. Because there are few, the water temperature changes at a low temperature as controlled.

  By moving (dissipating) the amount of heat that the refrigerant has through the first heat exchanger 3 disposed on the upstream side of the second heat exchanger 24 to the cooling water that is moving at this low temperature, The heat radiation load in the second heat exchanger 24 can be reduced, and the air conditioner performance of the entire heat pump circuit 20 can be improved.

  On the other hand, during the heating operation, in order to obtain the heater performance, the coolant temperature is controlled to change at a high temperature (about 80 ° C.).

  As described above, by appropriately changing the water temperature when the cooling water flows to the radiator 5 as necessary, it is possible to improve the air conditioner performance that tends to be reduced at low vehicle speed or when the vehicle is stopped during cooling operation. In the heating operation, high-temperature cooling water can be obtained, so that necessary heater performance can be ensured.

  In the embodiment described above, the stack 1 is exemplified as the prime mover, but it may be an engine.

As for the type of refrigerant, the mainstream refrigerant currently used in car air conditioners is HFC134a. However, it is desirable to use a CO ₂ refrigerant that operates in a supercritical state and easily reaches a high temperature.

  Further, in order to further improve the heat dissipation performance of the radiator 5, the front area of the second heat exchanger 24 disposed on the front surface of the radiator 5 may be reduced so that vehicle speed wind directly hits the radiator 5. good.

(Second embodiment)
In the first embodiment described above, only one stack 1 cooling circuit 10 is exemplified as the cooling water circuit. However, in actual vehicles, particularly fuel cell vehicles, there are many other cases where a cooling circuit is mounted on the vehicle.

For example, in order to cool the main body of the drive motor, a drive motor cooling circuit 30 is provided separately from the stack 1 cooling circuit 10. (See Figure 5)
In this way, a new dedicated circuit is provided so that the refrigerant can exchange heat with a cooling circuit other than the stack 1 cooling circuit 10 and with which the cooling water having a cooling water temperature lower than the cooling water flowing through the stack 1 cooling circuit 10 flows. By separately providing the heat exchanger, the air conditioner performance of the entire heat pump circuit 20 can be further increased.

(Constitution)
FIG. 5 shows a configuration in which heat is exchanged between the cooling water flowing through the cooling circuit other than the stack 1 cooling circuit 10 and the refrigerant flowing through the heat pump circuit 20.

  Since the flow direction of the cooling water in the stack 1 cooling water 10 is the same as that shown in the first embodiment, a description thereof will be omitted, and only the points different from the refrigerant flow of the heat pump circuit 20 shown in the first embodiment will be described. Is described below as an example.

  The refrigerant that has been compressed by the compressor 21 and has become a high temperature and a high pressure radiates heat to the cooling water flowing through the stack 1 cooling circuit 10 in the first heat exchanger 3.

  Thereafter, the refrigerant passes through the first expansion valve 22 and the four-way valve 23 that are fully opened, and flows into the fourth heat exchanger 32 that constitutes the drive motor 31 cooling circuit 30.

  The refrigerant that has dissipated heat into the cooling water flowing through the drive motor cooling circuit 30 in the fourth heat exchanger 32 then flows into the second heat exchanger 24, where it dissipates heat to the outside air by the vehicle speed wind. To do.

  Next, the heat is dissipated to the low-temperature and low-pressure refrigerant in the third heat exchanger 25, the air in the passenger compartment is cooled by the indoor heat exchanger 27, and then the four-way valve 23 is reached again, and the gas-liquid separation is performed by the accumulator 28. The process returns to the compressor 21.

  Thus, in the process of evaporating and cooling the air in the passenger compartment, the first heat exchanger 3 (dissipates heat to the cooling water of the stack 1 cooling circuit 10) and the fourth heat exchanger (drive motor cooling circuit). Heat is dissipated in 30 cooling water), the second heat exchanger 24 (dissipates heat in the air outside the passenger compartment), the third heat exchanger (dissipates heat in the low-pressure and low-temperature refrigerant), and four heat exchangers. In addition, it is possible to further improve the air conditioning efficiency than the configuration shown in the first embodiment.

  Although the above-described example is for the cooling operation, during the heating operation, the heat of the drive motor 31 can be absorbed from the cooling water flowing through the drive motor circuit 30, so that the temperature of the refrigerant can be further increased and the indoor heat exchange can be performed. In heat exchange (in this case, heating) with the air in the passenger compartment in the container 27, higher heating performance can be obtained.

(Modification)
The component corresponding to the valve shown in the claims shown in the first and second embodiments described above was the thermostat 4. However, instead of the thermostat 4, the water valves 8a and 8b and two water valves may be used. FIG. 6 shows a schematic configuration diagram of the vehicle air conditioner 100 when water valves 8 a and 8 b are used instead of the thermostat 4.

  Normally, the thermostat 4 can have only one temperature threshold. The first and second embodiments described above are described on the assumption that there is a thermostat 4 having a plurality of temperature thresholds.

  However, by using two well-known and low-priced water valves 8a and 8b, the present invention can be easily realized.

1 is a schematic configuration diagram of a vehicle air conditioner 100 according to a first embodiment of the present invention. (A) (b) is explanatory drawing of the structure of the 1st heat exchanger 3 which concerns on 1st embodiment of this invention. (A) is explanatory drawing which showed the opening / closing operation | movement of the thermostat 4 at the time of air_conditionaing | cooling operation, (b) is explanatory drawing which showed opening / closing operation | movement of the thermostat 4 at the time of heating operation. 4 is a flowchart showing a flow of opening and closing operation of the thermostat 4. It is a schematic block diagram of the vehicle air conditioner 100 which concerns on 2nd embodiment of this invention. It is a schematic block diagram of the vehicle air conditioner 100 which concerns on the modification of this invention.

Explanation of symbols

1 stack (motor)
2 Heater Core 3 First Heat Exchanger 4 Thermostat 5 Radiator 6 Pump 7 Cooling Water Channel 8a First Water Valve 8b Second Water Valve 10 Stack 1 Cooling Water Circuit (Motor Cooling Water Circuit)
20 Heat pump circuit (heat pump unit)
21 Compressor 22 First expansion valve 23 Four-way valve 24 Second heat exchanger 25 Third heat exchanger 26 Second expansion valve 27 Indoor heat exchanger 28 Accumulator 30 Drive motor 31 Cooling circuit 31 Drive motor 32 First Four heat exchangers 33 Second radiator 34 Second pump

Claims (6)

A prime mover having a heater core side flow path where the prime mover cooling water receiving heat generated from the prime mover flows to the heater core side for heat dissipation and returns to the prime mover, and a radiator side flow path which flows to the radiator side for heat dissipation and returns to the prime mover A cooling water circuit;
During cooling operation, the refrigerant is compressed by a compressor, the refrigerant is condensed by a second heat exchanger, the vehicle interior is cooled by an indoor heat exchanger,
During the heating operation, the refrigerant flow direction is changed by the four-way valves disposed on the suction side and the discharge side of the compressor, the heat is absorbed by the second heat exchanger, and the indoor heat exchanger is used. A vehicle air conditioner comprising a heat pump unit for heating the vehicle interior,
On the discharge side of the compressor, the first heat is disposed between the compressor and the four-way valve, and releases heat of the refrigerant compressed by the compressor to the prime mover cooling water in the heater core side flow path. An exchange is provided,
In the radiator side flow path, a flow path of the prime mover cooling water to the radiator side or the bypass flow path based on a bypass flow path in which the prime mover cooling water bypasses the radiator and a temperature of the prime mover cooling water. And a valve to adjust ,
The valve is configured to allow the prime mover cooling water to flow into the radiator when the cooling operation of the heat pump unit is performed and the prime mover cooling water is equal to or higher than a first temperature threshold.
At the time of the heating operation of the heat pump, and when the temperature of the prime mover cooling water is equal to or higher than a second temperature threshold value higher than the first temperature threshold value, the prime mover cooling water flows into the radiator side. An air conditioner for a vehicle. Between the second heat exchanger and the indoor heat exchanger during the cooling operation of the heat pump unit ,
Claims, characterized in that the high temperature and high pressure refrigerant discharged from the second heat exchanger, a third heat exchanger for exchanging heat between low-temperature and low-pressure refrigerant discharged from the indoor heat exchanger is provided The vehicle air conditioner according to 1 . According to claim 2, characterized in that the flow direction of the high-temperature high-pressure refrigerant flowing into the third heat exchanger, the flow direction of the low-temperature and low-pressure refrigerant is set to be counter-flow Vehicle air conditioner. Having other cooling water circuit through which cooling water lower than the temperature of the cooling water of the prime mover circulating through the prime mover cooling water circuit flows ;
Between the first heat exchanger and the second heat exchanger during the cooling operation of the heat pump unit ,
Claims 1 to 3, characterized in that the fourth heat exchanger to release heat of the high-temperature high-pressure refrigerant discharged from the first heat exchanger to the cooling water of the other cooling water circuit is provided The vehicle air conditioner according to any one of the above. The other cooling water circuit includes a second radiator that cools the cooling water flowing through the other cooling water circuit.
5. The vehicle air conditioner according to claim 4, wherein the second radiator and the second heat exchanger are arranged on an upstream side of an air flow of the radiator. 6. The refrigerant is air-conditioning system according to any one of claims 1 to 5, characterized in that a CO _2.

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