JP7312617B2 - vehicle air conditioner - Google Patents

Description

The present invention relates to a vehicle air conditioner.

An air conditioner is used in a vehicle to adjust the temperature in the room. An air conditioner basically supplies heat from an engine of a running vehicle to a heater core using a heat medium in a heat medium cycle, and supplies the refrigerant cooled in a refrigerant cycle to an evaporator, as disclosed in Patent Document 1, for example.

JP-A-08-040050 JP 2012-001141 A

By the way, in a hybrid vehicle or the like, the engine may stop even when the vehicle is stopped or running, and heat generation from the engine cannot always be expected, and a shortage of heat is likely to occur. Also, an electric vehicle does not have an engine.
Therefore, in recent years, some vehicles use a heat pump cycle that can be operated regardless of engine failure or stoppage to generate a heat medium or refrigerant used for air conditioning.
However, the cycle of the heat pump system is complicated, and as a result, the weight of the vehicle tends to increase. Vehicle weight directly affects fuel efficiency. In addition, even when the engine is stopped, the power source such as the motor is always operated for air conditioning, and the power stored in the battery for running is used. As a result, the travelable distance with the air conditioning on is reduced.

Therefore, as in Patent Document 2, it is conceivable to add a bypass circuit so as to include a compressor in the refrigerant cycle for cooling, and to exchange heat between the refrigerant in the bypass circuit and the heat medium in the heat medium cycle. As a result, the heat of the engine can be supplied to the heater core when the engine is operating, and the heat of the refrigerant can be exchanged with the heat medium when the engine is stopped on a downhill or the like. Without using a heavy and complicated heat pump cycle, the heat transfer medium can be expected to be warmed by heat exchange with the refrigerant even when the engine is stopped.
However, even if the refrigerant circulation path is simply switched from the normal refrigerant cycle to the bypass circuit to operate the compressor as in Patent Document 2, the heat medium cannot always be effectively warmed by heat exchange with the refrigerant. For example, the refrigerant that has not been operated just before is in a state of being cooled to the outside air temperature.

Thus, there is a demand for improvement in vehicle air conditioners.

A vehicle air conditioner according to the present invention includes: a heat medium cycle that supplies heat from a vehicle engine to a heater core using a heat medium; a refrigerant cycle that compresses a refrigerant with a compressor; a heat transfer device that is provided in the heat medium cycle and transfers heat from the compressor of the refrigerant cycle or heat from an exhaust pipe of the compressor to the heat medium; a tank that stores the refrigerant in the refrigerant cycle; of the refrigerant is stored in the tank to create an insufficient refrigerant state, and the compressor is operated.

Preferably, the tank can store more than half of the refrigerant of the refrigerant cycle .

Preferably, the heat exchanger houses at least part of the compressor and the exhaust pipe.

Preferably, a heat medium temperature sensor that detects the temperature of the heat medium output from the heat transfer device is provided, and the control unit preferably controls the rotation speed of the compressor according to the temperature of the heat medium detected by the heat medium temperature sensor.

Preferably, the vehicle includes an outside temperature sensor that detects an outside temperature of the vehicle, and the control unit stores the refrigerant of the refrigerant cycle in the tank when the outside temperature of the vehicle detected by the outside temperature sensor becomes low.
Preferably, the controller discharges the refrigerant stored in the tank from the tank when the outside air temperature detected by the outside air temperature sensor rises.

Preferably, the controller operates the compressor while the refrigerant of the refrigerant cycle is stored in the tank when the heat generation of the engine of the vehicle decreases.

Preferably, the control unit stops the compressor when the engine of the vehicle is in a state where heat can be generated.

Preferably, the refrigerant cycle circulates the refrigerant in an oil separator manner to ensure oil circulation to the compressor.

In the present invention, when supplying the heat medium to the heater core of the heat medium cycle, the refrigerant of the refrigerant cycle is stored in the tank. As a result, the refrigerant cycle can enter an insufficient refrigerant state. By operating the compressor under refrigerant starvation conditions, the compressor will generate more heat than would normally be the case without refrigerant starvation. The heat exchanger accommodates at least a part of the compressor and the exhaust pipe, and transfers the heat of the compressor, which is high in temperature due to operation in a state of insufficient refrigerant, or the heat of the exhaust pipe of the high-temperature compressor, to the heat medium. The heat medium is heated by the heat of the exothermic compressor or the exhaust pipe. As a result, in the present invention, the heat of the compressor that operates in a refrigerant shortage state can be supplied to the interior of the vehicle through the heater core of the heat medium cycle.
On the other hand, if the compressor is operated without, for example, an insufficient refrigerant state, the compressor does not generate much heat. The temperature of the refrigerant does not rise too much. Moreover, it takes time for the temperature of the compressor and the refrigerant to rise. In this case, it is not easy to operate the compressor when the amount of heat in the heat medium is insufficient, immediately raise the temperature to a high temperature immediately after the start of operation, and supply the heat to the interior of the vehicle through the heater core of the heat medium cycle.
Moreover, in the present invention, the refrigerant cycle and the heat medium cycle are combined. Therefore, in the present invention, it is possible to warm the heat transfer medium well and use it for warming the interior of the vehicle when the engine is stopped without using a heavy and complicated heat pump type cycle. As a result, in the present invention, it is possible to reduce the need to operate the engine when it is not necessary for driving, for example, just for temperature control. In addition, in the present invention, the amount of heat generated per unit of energy for operating the compressor can be increased, so the fuel efficiency of the vehicle can be improved due to the high heat generation efficiency.
Thus, the present invention can improve the air conditioning system of a vehicle.

FIG. 1 is an explanatory diagram of a vehicle air conditioner according to an embodiment of the present invention. FIG. 2 is a flow chart of storage control of the refrigerant in the tank by the air conditioning ECU of FIG. FIG. 3 is a flow chart of compressor operation control by the air conditioning ECU of FIG. FIG. 4 is a schematic timing chart of an example of heat medium control by the vehicle air conditioner of FIG. The horizontal axis is time.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 1 is an explanatory diagram of a vehicle air conditioner 1 according to an embodiment of the present invention.
The vehicle air conditioner 1 of FIG. 1 has a refrigerant cycle 10, a heat medium cycle 20, and an air conditioning ECU 31 as a control unit that controls the operations of these. The refrigerant cycle 10 and the heat medium cycle 20 are provided, for example, together with the engine 22 of the vehicle in the engine room of the vehicle.

In order to circulate the refrigerant, the refrigerant cycle 10 includes a compressor 11, an oil separator 12, a condenser 13, an expansion valve 14, and an evaporator 15, which are connected in that order by pressure-resistant tubes. The evaporator 15 is provided in the air conditioning duct 2 leading to the interior of the vehicle.
The refrigerant may be, for example, R12, r134a, or the like.
Compressor 11 compresses the refrigerant and supplies it to condenser 13 through oil separator 12 . The condenser 13 condenses and liquefies the compressed refrigerant. The expansion valve 14 sprays the refrigerant liquefied by condensation toward the evaporator 15 . The sprayed coolant is vaporized in the evaporator 15 . As the liquid refrigerant evaporates, the evaporator 15 absorbs heat of vaporization from its surroundings. Air in the air conditioning duct 2 is cooled by the evaporator 15 .
The vaporized refrigerant is supplied from the evaporator 15 to the compressor 11 and compressed again. In this manner, the refrigerant cycle 10 can continue to circulate the refrigerant and cool the air within the air conditioning duct 2 .
The oil separator 12 separates oil mixed with the refrigerant and returns it to the compressor 11 . Thereby, the compressor 11 can ensure oil circulation to the compressor 11 .

In order to circulate the heat medium, the heat medium cycle 20 includes a water pump 21, a vehicle engine 22, a heat transfer device 23, and a heater core 24, which are connected in that order by a pressure-resistant tube. The heater core 24 is provided in the air conditioning duct 2 leading to the interior of the vehicle. In addition, the heat medium cycle 20 may also include a radiator (not shown) connected in parallel with the heater core 24 and the heat transfer device 23 . The radiator cools the heat medium with outside air.
The heat medium may be cooling water, for example. The heat medium may also be, for example, cooling oil.
The water pump 21 forcedly circulates cooling water as a heat medium in the heat medium cycle 20 . The heat medium that has passed through the engine 22 is warmed by exhaust heat from the operating engine 22 , passes through the heat transfer device 23 , and circulates to the heater core 24 . The heater core 24 is heated by being supplied with the heat of the vehicle engine 22 by the heat medium, and heats the air in the air conditioning duct 2 . Air in the air conditioning duct 2 is heated by the heater core 24 .
The heat medium that has passed through the heater core 24 is supplied to the water pump 21 again. In this manner, the heat medium cycle 20 can continue to heat the air in the air conditioning duct 2 by circulating the heat medium.

The air conditioning ECU 31 is connected to an in-vehicle network 30 provided in the vehicle. In addition, an engine ECU 32, a travel control ECU 33, a user interface ECU 34, and the like are also connected to the in-vehicle network 30, for example.
The air conditioning ECU 31 controls the operation of the refrigerant cycle 10 and the heat medium cycle 20 based on the temperature setting from the user interface ECU 34 so that the temperature of the passenger compartment reaches the set temperature.

By the way, the engine ECU 32 of the vehicle executes control to stop the engine 22 when the driving force of the engine 22 is unnecessary while the vehicle is stopped or running. Also, if the vehicle has a motor or the like as a power source other than the engine 22, the engine ECU 32 may stop the engine 22 and run the vehicle by driving the motor. When the engine 22 is controlled to be stopped while the vehicle is running in this way, the amount of heat generated by the engine 22 may be reduced compared to when the engine 22 is continuously operated without being stopped while the vehicle is running. In this case, the heat medium cycle 20 cannot be expected to generate heat from the engine 22 at all times, and the amount of heat is likely to be insufficient during the stop control of the engine 22 . When the amount of heat is insufficient, the air conditioning ECU 31 cannot warm the vehicle compartment to the set temperature or maintain the vehicle compartment at the set temperature even if the heat medium cycle 20 is operated.

Therefore, recently, an increasing number of vehicles heat or cool a heat medium used for air conditioning using a heat pump cycle that can be operated regardless of whether the engine 22 is stopped.
However, in the heat pump type cycle, the cycle is complicated and the weight of the air conditioner 1 is increased in order to be able to heat and cool the heat medium. Vehicle weight directly affects fuel efficiency.
Moreover, in the heat pump cycle, the motor for air conditioning continues to operate even when the engine 22 is operating. As a result, the electric power stored in the running battery continues to be consumed for air conditioning. The mileage that can be traveled with the air conditioning on is significantly reduced.

Thus, the vehicle air conditioner 1 is required to be improved.

Therefore, in the present embodiment, a heat transfer device 23 is provided between, for example, the engine 22 and the heater core 24 of the heat medium cycle 20 . The heat transfer device 23 is a container that accommodates the compressor 11 of the refrigerant cycle 10 and the exhaust pipe 16 of the compressor 11 . The heat transfer device 23 may be formed in a heat insulating structure to suppress heat radiation from the heat transfer device 23 . Thereby, the heat transfer device 23 can transfer the heat of the compressor 11 of the refrigerant cycle 10 or the heat of the exhaust pipe 16 of the compressor 11 to the heat medium.

Further, the refrigerant cycle 10 is provided with a tank 17 for storing refrigerant. The tank 17 is formed in a size capable of storing 70% to 80% or more of the refrigerant of the refrigerant cycle 10 . The tank 17 may be sized to store more than half of the refrigerant in the refrigerant cycle 10 . The tank 17 is connected in parallel with the expansion valve 14 in the refrigerant cycle 10, for example. A branch pipe that branches the refrigerant to the tank 17 is provided with an inflow valve 18 whose opening and closing can be controlled. A return pipe for returning the refrigerant from the tank 17 is provided with an outflow valve 19 that can be controlled to open and close.

An outside air temperature sensor 35 and a heat medium temperature sensor 36 are connected to the air conditioning ECU 31 as a control unit.
The outside air temperature sensor 35 detects the outside air temperature of the vehicle.
A heat medium temperature sensor 36 detects the temperature of the heat medium output from the heat transfer device 23 .

The air conditioning ECU 31 uses the temperatures detected by these temperature sensors 35 and 36 to control the circulation of the refrigerant in the refrigerant cycle 10 and the circulation of the heat medium in the heat medium cycle 20 . Specifically, the air conditioning ECU 31 controls opening and closing of the inflow valve 18 , opening and closing of the outflow valve 19 , stoppage of operation of the compressor 11 , and stoppage of operation of the water pump 21 . For example, when supplying a heat medium to the heater core 24 to raise the temperature of the passenger compartment, the air conditioning ECU 31 operates the water pump 21 to circulate the heat medium in the heat medium cycle 20 . When supplying refrigerant to the evaporator 15 to lower the temperature of the passenger compartment, the air conditioning ECU 31 operates the compressor 11 with both the inflow valve 18 and the outflow valve 19 closed to circulate the refrigerant in the refrigerant cycle 10 .

FIG. 2 is a flow chart of refrigerant storage control by the air conditioning ECU 31 of FIG.
The air-conditioning ECU 31 repeatedly executes the process of FIG. 2, for example, when an occupant is in the vehicle.

In step ST1, the air conditioning ECU 31 compares the outside air temperature of the vehicle detected by the outside air temperature sensor 35 with the heating required temperature. The heating required temperature may be, for example, the maximum temperature at which heating of the passenger compartment is considered necessary. When the outside air temperature of the vehicle is equal to or lower than the heating required temperature, the air conditioning ECU 31 advances the process to step ST3. When the outside air temperature of the vehicle is higher than the heating required temperature, the air conditioning ECU 31 advances the process to step ST2.

In step ST2, the air-conditioning ECU 31 determines whether it is necessary to heat the interior of the vehicle. For example, when there is an instruction to heat the interior of the vehicle from the user interface ECU 34, the air conditioning ECU 31 determines that the heating of the interior of the vehicle is necessary, and advances the process to step ST2. When there is no instruction to heat the interior of the vehicle from the user interface ECU 34, the air conditioning ECU 31 determines that the heating of the interior of the vehicle is unnecessary, and advances the process to step ST4.

In step ST<b>3 , the air conditioning ECU 31 stores the refrigerant of the refrigerant cycle 10 in the tank 17 . The air conditioning ECU 31 opens the inflow valve 18 while keeping the outflow valve 19 closed, and operates the compressor 11 . Thereby, the refrigerant of the refrigerant cycle 10 flows into the tank 17 and is compressed and accumulated. The air conditioning ECU 31, for example, repeatedly measures the internal pressure of the tank 17 with a pressure sensor (not shown) or measures the elapsed time with a timer (not shown), and when it is considered that 70% to 80% or more of the refrigerant in the refrigerant cycle 10 is accumulated in the tank 17, the inflow valve 18 is closed while the outflow valve 19 is closed. As a result, the refrigerant cycle 10 enters an insufficient refrigerant state.

In step ST<b>4 , the air conditioning ECU 31 returns the refrigerant stored in the tank 17 to the refrigerant cycle 10 . The air conditioning ECU 31 opens the outflow valve 19 while keeping the inflow valve 18 closed, and operates the compressor 11 . Thereby, the refrigerant in the tank 17 returns to the refrigerant cycle 10 . The air conditioning ECU 31, for example, repeatedly measures the internal pressure of the tank 17 using a pressure sensor (not shown) or measures the elapsed time using a timer (not shown), and closes the outflow valve 19 while keeping the inflow valve 18 closed when the tank 17 is considered to run out of refrigerant. The tank 17 is thereby separated from the refrigerant cycle 10 . The refrigerant cycle 10 is brought to a state where a normal amount of refrigerant is present. The air conditioning ECU 31 discharges the refrigerant stored in the tank 17 from the tank 17 when the outside air temperature detected by the outside air temperature sensor 35 is high enough to eliminate the need for heating the vehicle interior.

Thus, in the present embodiment, by proceeding to step ST3 based on the determination in step ST2, the refrigerant of the refrigerant cycle 10 can be stored in the tank 17 even if the determination in step ST2 does not proceed to step ST3.
In addition, regardless of the judgment in step ST2, the process proceeds to step ST3 by the judgment in step ST1, and even if the vehicle interior heating is operated while the engine 22 is stopped while the vehicle is running, the refrigerant cycle 10 is prepared in advance in an insufficient refrigerant state, and the compressor 11 can be immediately operated to generate heat.

FIG. 3 is a flow chart of operation control of the compressor 11 by the air conditioning ECU 31 of FIG.
The air-conditioning ECU 31 repeatedly executes the process of FIG. 3, for example, when an occupant is in the vehicle.

In step ST11, the air conditioning ECU 31 determines whether or not the refrigerant has been stored in the tank 17 in step ST3 of FIG. When the storage of the refrigerant in the tank 17 is completed, the air conditioning ECU 31 advances the process to step ST12. If the storage of the refrigerant in the tank 17 has not been completed, the air conditioning ECU 31 terminates the processing of FIG. When the storage of the refrigerant in the tank 17 is completed, the refrigerant cycle 10 is in a state of insufficient refrigerant.

In step ST12, the air-conditioning ECU 31 determines whether it is necessary to heat the interior of the vehicle. For example, when the user interface ECU 34 issues an instruction to start heating the interior of the vehicle, the air conditioning ECU 31 determines that the heating of the interior of the vehicle is necessary, and advances the process to step ST13. When the user interface ECU 34 does not give an instruction to start heating the vehicle interior, the air conditioning ECU 31 determines that the heating of the vehicle interior is unnecessary, and terminates the processing of FIG. 3 . When the user interface ECU 34 issues an instruction to start heating the vehicle interior, the air conditioning ECU 31 has already started to heat the vehicle interior by circulating the heat medium in the heat medium cycle 20 . Therefore, the air-conditioning ECU 31 advances the process to step ST13 after starting heating using the heat medium cycle 20 in response to the instruction to warm the vehicle interior.

In step ST13, the air conditioning ECU 31 determines whether the heat generation of the engine 22 of the vehicle is reduced based on whether or not the engine 22 is stopped. The engine ECU 32 stops the supply of fuel to the engine 22 in response to an instruction from the travel control ECU 33, for example, when the vehicle travels down a long downhill slope or when the vehicle stops at idling. The air conditioning ECU 31 determines that the engine 22 is to be stopped, for example, upon obtaining an instruction from the travel control ECU 33 to the engine ECU 32, and advances the process to step ST14. When determining that the engine 22 is not stopped, the air conditioning ECU 31 advances the process to step ST18.

In step ST14, the air conditioning ECU 31 determines whether or not the temperature of the heat medium output from the heat transfer device 23 detected by the heat medium temperature sensor 36 is equal to or lower than a predetermined auxiliary start temperature. The auxiliary start temperature may be, for example, a temperature lower than the steady-state temperature of the heat medium when the engine 22 is continuously operated under normal load in winter. Also, as will be described later, the auxiliary start temperature is preferably set to a temperature higher than the insufficient heat quantity temperature at which the heat transfer medium cannot sufficiently heat the passenger compartment due to insufficient heat quantity. When the detected temperature of the heat medium is equal to or lower than the assist start temperature, the air conditioning ECU 31 advances the process to step ST16. When the detected temperature of the heat medium is higher than the auxiliary start temperature, the air conditioning ECU 31 advances the process to step ST15.

In step ST15, the air conditioning ECU 31 determines whether or not the detected temperature of the heat medium is equal to or higher than a predetermined auxiliary stop temperature. The auxiliary stop temperature may be higher than the auxiliary start temperature and lower than the steady-state temperature of the heat medium when the engine 22 is continuously operating under normal load in winter, for example. Also, the auxiliary stop temperature may be higher than the auxiliary start temperature and lower than the heat resistant temperature of the compressor 11 . When the detected temperature of the heat medium is equal to or higher than the auxiliary stop temperature, the air conditioning ECU 31 advances the process to step ST18. When the detected temperature of the heat medium is lower than the auxiliary stop temperature, the air conditioning ECU 31 advances the process to step ST16.

In step ST<b>16 , the air conditioning ECU 31 acquires the rotational speed of the compressor 11 according to the temperature of the heat medium output from the heat transfer device 23 detected by the heat medium temperature sensor 36 . The air-conditioning ECU 31 obtains the obtainable rotation speed of the compressor 11 from a rotation speed range in which the compressor 11 operating in an insufficient refrigerant state does not exceed its heat-resistant temperature. The air-conditioning ECU 31 may obtain a higher rotation speed within that rotation speed range as the temperature of the heat medium is higher. The energy consumed for rotating the compressor 11 can be optimized by not increasing the number of revolutions more than necessary.

In step ST17, the air conditioning ECU 31 operates the compressor 11 at the obtained rotational speed. As a result, the compressor 11 can operate in a refrigerant shortage state when the engine 22 is stopped, and the heating medium can be heated by the heat generated by the compressor 11 . Even though the engine 22 is stopped, the heat medium can be heated by the compressor 11 and maintained at the same high temperature as before the engine 22 was stopped, for example. Moreover, even when the temperature is lower than before the engine 22 is stopped, the rate of decrease in the temperature of the coolant can be reduced. After that, the air conditioning ECU 31 advances the process to step ST19.

In step ST<b>18 , the air conditioning ECU 31 stops the compressor 11 . This makes it possible to stop the operation of the compressor 11 in the insufficient refrigerant state. As a result, when the engine 22 is operating, the compressor 11 can be prevented from operating in an insufficient refrigerant state.

In step ST19, the air conditioning ECU 31 determines whether or not the heating of the room is finished. The air-conditioning ECU 31 determines that the heating of the interior of the vehicle has ended, and advances the process to step ST20 when, for example, the passenger gets off the vehicle or the user interface ECU 34 issues an instruction to end the heating of the interior of the vehicle. When there is no instruction to end heating of the vehicle interior, the air conditioning ECU 31 returns the process to step ST3. The air-conditioning ECU 31 repeats the processing from step ST3 to step ST19 until an instruction to end heating of the vehicle interior is given. During this time, if the detected temperature of the heat medium is lower than the auxiliary stop temperature, the compressor 11 operates in an insufficient refrigerant state by the processing of steps ST16 and ST17. When the detected temperature of the heat medium is equal to or higher than the auxiliary stop temperature, the process of step ST18 stops the operation of the compressor 11 in the insufficient refrigerant state.

In step ST20, the air conditioning ECU 31 stops the compressor 11 in operation. After that, the air conditioning ECU 31 terminates the processing of FIG.

FIG. 4 is a schematic timing chart of an example of heat medium control by the vehicle air conditioner 1 of FIG. The horizontal axis is time.
FIG. 4A shows the operating state of the engine 22 during running. For example, the engine 22 is stopped when driving down a long downhill during driving, or when decelerating or stopping for a long period of time during driving.
FIG. 4B shows the operating state of the compressor 11 . The compressor 11 continues to operate continuously while the engine 22 is stopped in FIG. 4(A).

FIG. 4C shows the detected temperature of the heat medium. The detected temperature of the heat medium begins to drop when the engine 22 stops during running. However, since the heat medium is heated by the heat generated by the compressor 11 which operates in a refrigerant shortage state and generates heat, the temperature drop of the heat medium is suppressed as indicated by the solid line in FIG. 4(C). After that, when the engine 22 resumes operation, the temperature of the heat medium recovers to the same temperature as before the stop. The dashed line in FIG. 4C is the detected temperature of the heat medium when the compressor 11 is not operated while the engine 22 is stopped. In this case, if the period during which the engine 22 is stopped becomes longer, the temperature of the heat medium from which heat is taken away by the heater core 24 becomes insufficient and becomes lower than the lower limit temperature at which the vehicle interior can be warmed well. When the amount of heat becomes insufficient, the air conditioning ECU 31 outputs an instruction to start the engine 22 to the engine ECU 32 . As a result, the engine 22 is started as indicated by the dashed line in FIG. 4(A). The engine 22 starts earlier than the period in which the engine 22 can stop. The period during which the engine 22 is actually stopped is shorter than the period during which the engine 22 can be stopped.
On the other hand, in the solid line of FIG. 4(C), the temperature of the heat medium does not fall below the lower limit temperature even if the engine 22 is stopped for a long period of time. The passenger compartment can be kept well warmed. The engine 22 is allowed to actually stop during the period in which the engine 22 can be stopped.

As described above, in this embodiment, when supplying the heat medium to the heater core 24 of the heat medium cycle 20 , the refrigerant of the refrigerant cycle 10 is stored in the tank 17 . The tank 17 may store, for example, half or more of the refrigerant in the refrigerant cycle 10 , preferably 70% to 80% or more. As a result, the refrigerant cycle 10 enters an insufficient refrigerant state. By operating the compressor 11 in this insufficient refrigerant state, the compressor 11 generates heat to a temperature higher than that in a normal case where the refrigerant is not in an insufficient refrigerant state. The heat transfer device 23 is a container that accommodates the compressor 11 and the exhaust pipe 16 . The heat transfer device 23 transfers the heat of the compressor 11, which operates in a refrigerant shortage state and reaches a high temperature, or the heat of the exhaust pipe 16 of the high-temperature compressor 11 to the heat medium. The heat medium can be well heated by the heat of the compressor 11 or the exhaust pipe 16 that generates heat. As a result, in the present embodiment, the heat of the compressor 11 operating in the insufficient refrigerant state can be supplied to the interior of the vehicle through the heater core 24 of the heat medium cycle 20 .
On the other hand, if the compressor 11 were to be operated without, for example, an insufficient refrigerant state, the compressor 11 would not generate much heat, and it would take a long time to generate that little heat. The compressor 11 cannot be instantly heated to a high temperature immediately after the start of operation.
Moreover, in this embodiment, the heat medium can be well warmed and used to heat the interior of the vehicle when the engine 22 is stopped without using a heavy and complicated heat pump cycle. As a result, in this embodiment, it is not necessary to operate the engine 22 in a state that is not necessary for running, for example, just for temperature control. In addition, in the present embodiment, heat generation per unit energy for operating the compressor 11 is increased, so high heat generation efficiency can be obtained and the fuel efficiency of the vehicle can be improved. In this embodiment, the vehicle air conditioner 1 can be improved.

In this embodiment, the rotation speed of the compressor 11 is controlled according to the temperature of the heat medium detected by the heat medium temperature sensor 36 . Therefore, the rotation speed of the compressor 11 can be controlled so that the compressor 11 operating in a state of insufficient refrigerant does not exceed its heat-resistant temperature.

In this embodiment, when the outside air temperature of the vehicle detected by the outside air temperature sensor 35 becomes low, the refrigerant of the refrigerant cycle 10 is stored in the tank 17 . Therefore, when the outside air temperature becomes low and it becomes necessary to heat the interior of the vehicle, it is possible to operate the compressor 11 in an insufficient refrigerant state. Then, when the heat generation of the engine 22 of the vehicle actually decreases, the compressor 11 is operated while the refrigerant of the refrigerant cycle 10 is stored in the tank 17 . For example, when the vehicle is running downhill or when the supply of fuel to the engine 22 is stopped, the compressor 11 is operated while the refrigerant of the refrigerant cycle 10 is stored in the tank 17 . Therefore, in the present embodiment, the heat of the compressor 11 or the heat of the exhaust pipe 16 operating in the insufficient refrigerant state can be used to effectively warm the heat medium and heat the interior of the vehicle. In this embodiment, the chances of starting the engine 22 only for temperature control can be reduced, and fuel efficiency can be improved.

In this embodiment, the compressor 11 is stopped when the engine 22 of the vehicle is in a state where it can generate heat. For example, the compressor 11 is stopped when the running vehicle changes from a downhill to a level ground, or when fuel supply to the engine 22 is restarted. Therefore, it is possible to reduce the possibility that the compressor 11 will continue to operate in an insufficient refrigerant state in a state where the heating medium is warmed by the heat generated by the engine 22 of the vehicle, and that the compressor 11 will cause trouble due to excessive heating or the like.

In this embodiment, when the outside air temperature detected by the outside air temperature sensor 35 rises, the refrigerant stored in the tank 17 is discharged from the tank 17 . As a result, the refrigerant cycle 10 can cool the evaporator 15 with the refrigerant as usual when the outside air temperature is high.

In this embodiment, the refrigerant cycle 10 circulates the refrigerant by means of an oil separator 12 so as to ensure oil circulation to the compressor 11 while the refrigerant is stored in the tank 17 . As a result, the compressor 11 can ensure lubrication with oil even when it operates in an insufficient refrigerant state, and can effectively suppress seizure.

The above embodiments are examples of preferred embodiments of the present invention, but the present invention is not limited to these, and various modifications and changes are possible without departing from the scope of the invention.

For example, in the above embodiment, the heat transfer device 23 is a container that houses the compressor 11 and the exhaust pipe 16 as a whole.
Alternatively, for example, heat transfer device 23 may house compressor 11 and part of exhaust pipe 16 .

DESCRIPTION OF SYMBOLS 1... Vehicle air conditioner, 2... Air-conditioning duct, 10... Refrigerant cycle, 11... Compressor, 12... Oil separator, 13... Condenser, 14... Expansion valve, 15... Evaporator, 16... Exhaust pipe, 17... Tank, 20... Heat medium cycle, 22... Engine, 23... Heat transfer device, 24... Heater core, 31... Air conditioning ECU, 35... Outside air temperature sensor, 36... Heat medium temperature sensor

Claims (9)

a heat medium cycle for supplying heat from a vehicle engine to a heater core using a heat medium;
a refrigerant cycle for compressing refrigerant with a compressor;
a heat exchanger provided in the heat medium cycle for transferring the heat of the compressor of the refrigerant cycle or the heat of the exhaust pipe of the compressor to the heat medium;
a tank for storing the refrigerant of the refrigerant cycle;
a control unit that controls the refrigerant cycle;
has
When a heat medium is supplied to the heater core, the control unit stores the refrigerant of the refrigerant cycle in the tank to bring the refrigerant into an insufficient refrigerant state and causes the compressor to operate.
vehicle air conditioning.
The tank can store half or more of the refrigerant of the refrigerant cycle ,
The vehicle air conditioner according to claim 1 .
the heat exchanger houses at least a portion of the compressor and the exhaust pipe;
3. The vehicle air conditioner according to claim 1 or 2.
a heat medium temperature sensor that detects the temperature of the heat medium output from the heat transfer device;
The control unit controls the rotation speed of the compressor according to the temperature of the heat medium detected by the heat medium temperature sensor.
The vehicle air conditioner according to any one of claims 1 to 3.
an outside temperature sensor that detects the outside temperature of the vehicle;
The control unit stores the refrigerant of the refrigerant cycle in the tank when the outside temperature of the vehicle detected by the outside temperature sensor becomes low.
The vehicle air conditioner according to any one of claims 1 to 4.
The control unit discharges the refrigerant stored in the tank from the tank when the outside temperature detected by the outside temperature sensor rises.
The vehicle air conditioner according to claim 5 .
When the heat generation of the engine of the vehicle is reduced, the control unit operates the compressor while the refrigerant of the refrigerant cycle is stored in the tank.
The vehicle air conditioner according to any one of claims 1 to 6.
The control unit stops the compressor when the engine of the vehicle is in a state where it can generate heat.
The vehicle air conditioner according to any one of claims 1 to 7.
the refrigerant cycle circulates the refrigerant through an oil separator scheme to ensure oil circulation to the compressor;
The vehicle air conditioner according to any one of claims 1 to 8.

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