JP2014088151A - Vehicle air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle air conditioner capable of suppressing generation of abnormal sound during switching of an air conditioning operation mode.SOLUTION: A vehicle air conditioner includes compression means driven by power supplied from a secondary battery to compress a heat medium, pressure reduction means for reducing the pressure of the heat medium, a heat exchanger for exchanging heat between the heat medium and air, a flow path having a heating path on which the heat medium passes during heating and a cooling path on which the heat medium passes during cooling, a flow path selector valve for changing the path of the flow path according to an air conditioning operation mode, and a control unit for operating the flow path selector valve. The control unit stops the compression means when a switching command of the air conditioning operation mode is input, and stops the switching operation of the flow path selector valve until the pressure difference of the paths becomes equal to or less than a predetermined value.

Description

  The present invention relates to a vehicle air conditioner.

  Conventionally, as a vehicle air conditioner, a heat pump system (vapor compression refrigeration cycle) having a compressor, an indoor condenser, an outdoor condenser, an indoor evaporator, and a decompression unit is known. In an electric vehicle, unlike an engine vehicle, heat from a drive source cannot be used for heating, and thus such a heat pump system is employed (see, for example, Patent Document 1). In the heat pump system described in Patent Document 1, the cooling medium that is decompressed and expanded by the decompression means during cooling is heat-exchanged by the indoor evaporator to cool the air, and is compressed by the compressor during heating and is heated by the indoor condenser. There is a heating channel that heats the air by exchanging heat with the medium. And the flow path switching means switches the flow path during cooling and heating.

JP 2011-240725 A

  In such a heat pump system, since the heat medium is compressed and expanded, the pressure applied to the heat medium differs between the cooling channel and the heating channel. There is a problem that there is.

  Therefore, an object of the present invention is to solve the above-described problems of the prior art and to provide a vehicle air conditioner capable of suppressing the generation of abnormal noise when switching the operation mode of air conditioning. is there.

  The vehicle air conditioner according to the present invention is driven by power supply from a secondary battery, and compresses the heat medium, a decompression means that depressurizes the heat medium, and heat exchange between the heat medium and air. A flow path having a heating path through which the heat medium passes during heating and a cooling path through which the heat medium passes during cooling, and a path for changing the path in the flow path according to the air conditioning operation mode A switching valve and a control unit that operates the flow path switching valve, and when the air conditioning operation mode switching command is input, the control unit stops the compression means, and the pressure difference of the path The switching operation of the flow path switching valve is stopped until is below a predetermined value.

  In the present invention, when there is a command to switch the air-conditioning operation mode, the control unit stops the compression unit and performs the switching operation of the flow path switching valve until the pressure difference in the path becomes a predetermined value or less. By stopping, it is possible to suppress the generation of noise due to the pressure difference of the heat medium when the flow path switching valve is switched.

  As a preferred embodiment of the present invention, when the switching command for the air conditioning operation mode is a switching command for cooling operation and heating operation, the compression means is stopped and the pressure difference in the flow path is predetermined. After the switching operation of the flow path switching valve is stopped until it becomes less than or equal to the value, when the pressure difference in the flow path becomes smaller than a predetermined value, the compression means is operated again and the switching operation of the flow path switching valve is performed. To do.

  The control unit includes a pressure measurement unit that measures a pressure in the flow path, and the control unit determines that a pressure difference in the flow path is a predetermined value if the pressure measured by the pressure measurement unit is equal to or less than a predetermined value. It is preferable to perform the switching operation of the flow path switching valve by determining that it is the following. By measuring the pressure in this way, it is possible to easily estimate and determine that the pressure difference is equal to or less than a predetermined value.

  The control unit includes a time measurement unit, and the control unit starts measurement by the time measurement unit when a cooling / heating switching command is input, and determines that the measurement time exceeds a predetermined time. It is preferable that it is possible to determine that the difference is equal to or less than a predetermined value and to perform the switching operation of the flow path switching valve. By measuring the time in this way, it is possible to easily estimate and determine that the pressure difference is equal to or less than a predetermined value.

  According to the vehicle air conditioner of the present invention, it is possible to achieve an excellent effect that it is possible to suppress the generation of abnormal noise when switching between cooling and heating.

The schematic diagram of the heat pump system concerning the vehicle air conditioner of this embodiment. The schematic diagram for demonstrating the drive of the heat pump system at the time of air_conditioning | cooling of a vehicle air conditioner. The schematic diagram for demonstrating the drive of the heat pump system at the time of the heating of a vehicle air conditioner. The timing chart which shows the switching timing of the solenoid valve in a vehicle air conditioner.

  First, the heat pump system concerning the vehicle air conditioner of this embodiment is demonstrated using FIG.

  The vehicle air conditioner I has a heat pump system 1. The heat pump system 1 includes an electric compressor (compression means) 11, an indoor condenser (heat exchanger) 12, an outdoor condenser (heat exchanger) 13, an evaporator (heat exchanger) 14, an accumulator 15, and a first expansion valve (decompression means). 21 and a second expansion valve (decompression means) 22, which are connected by a pipe 16 constituting a flow path of the heat medium. As will be described in detail later, the heat pump system 1 includes a cooling path configured by connecting an electric compressor 11, an indoor condenser 12, an outdoor condenser 13, a second expansion valve 22, and an accumulator 15 in this order by a pipe 16. Moreover, the heat pump system 1 includes a heating path configured by connecting an electric compressor 11, an indoor condenser 12, a first expansion valve 21, an outdoor condenser 13, and an accumulator 15 in this order by a pipe 16.

  The vehicle air conditioner I includes a control unit 10 for driving the heat pump system 1. The control unit 10 includes a pressure detection sensor 31 for detecting the pressure of the heat medium. In the present embodiment, the pressure detection sensor 31 is provided between the indoor capacitor 12 and the two-way electromagnetic valve 23. The pressure detection sensor 31 detects the pressure of the heat medium when the vehicle power supply is on, and sends the detected pressure value to the control unit 10.

  When the air compressor operation instruction is input by the occupant, the electric compressor 11 that receives power supply from the driving secondary battery starts to be driven by the control unit 10 and compresses the heat medium into a high temperature and high pressure state.

  The indoor condenser 12 performs heat exchange between the heat medium and the air in the passenger compartment. The indoor condenser 12 is provided in the air conditioning housing 17. In the air conditioning housing 17, a blower fan (not shown), the above-described evaporator 14, air mix damper 18, and PTC heater 19 are provided. The indoor condenser 12 is provided on the downstream side of the evaporator 14 in the air conditioning housing 17. In addition, the air mix damper 18 is provided between the evaporator 14 and the indoor condenser 12 and is configured so that the open / close state differs between heating and cooling. The PTC heater 19 is provided on the downstream side of the indoor condenser 12. The heat medium that has passed through the indoor condenser 12 is sent to the outdoor condenser 13 via the pipe 16.

  A pipe 16 between the indoor capacitor 12 and the outdoor capacitor 13 is provided with a first expansion valve 21 and a two-way electromagnetic valve 23 provided in parallel to the first expansion valve 21. The opening and closing of the two-way solenoid valve 23 is controlled by the control unit 10. When the two-way solenoid valve 23 is turned on, the heat medium flows through the first expansion valve 21 side, and when the two-way solenoid valve 23 is turned off, the heat medium flows through the two-way solenoid valve 23 side. Flowing.

  The outdoor condenser 13 performs heat exchange between the heat medium and the air outside the passenger compartment. A three-way electromagnetic valve 24 is provided on the downstream side of the outdoor condenser 13, and the flow path through which the heat medium passes can be changed by switching the three-way electromagnetic valve 24 during cooling and heating. That is, the heat medium that has passed through the outdoor condenser 13 is sent to the evaporator 14 during cooling via the pipe 16a as will be described in detail later, and is sent to the accumulator 15 via the pipe 16b during heating. In the present embodiment, the switching operation of the three-way solenoid valve 24 is controlled by the control unit 10. That is, when the control unit 10 controls the three-way electromagnetic valve 24 to be in the on state, the heat medium flows through the pipe 16a, and when the three-way electromagnetic valve 24 is controlled to be in the off state, the heat medium flows through the pipe 16b.

  A second expansion valve 22 is provided between the three-way solenoid valve 24 and the evaporator 14. The second expansion valve 22 functions as a decompression unit, and expands and decompresses the heat medium to lower the heat medium temperature.

  The evaporator 14 performs heat exchange between the heat medium and the air in the passenger compartment, and cools the air sent to the passenger compartment.

  The accumulator 15 functions as a heat medium reservoir.

  The operation of the heat pump system during cooling will be described with reference to FIG.

  When the cooling instruction is input by the occupant, the control unit 10 controls the two-way solenoid valve 23 to be turned off and the three-way solenoid valve 24 to be turned on, and operates the electric compressor 11.

  From the electric compressor 11, the heat medium compressed to a high temperature and high pressure is input to the indoor condenser 12 through the pipe 16. Since the indoor condenser 12 does not operate during cooling, the heat medium simply passes through the indoor condenser 12. Note that the air mix damper 18 is set in an open / closed state so as to face the indoor condenser 12 during cooling.

  The heat medium that has passed through the indoor condenser 12 flows through the two-way electromagnetic valve 23 side and is input to the outdoor condenser 13 because the two-way electromagnetic valve 23 is in the OFF state. The heat medium input to the outdoor condenser 13 dissipates heat by exchanging heat with the outdoor air using the outdoor condenser 13, and the heat medium temperature is slightly lowered.

  Next, since the three-way solenoid valve 24 is in the ON state, the heat medium from the outdoor condenser 13 is input to the second expansion valve 22 and the heat medium is depressurized. The temperature of the decompressed heat medium also decreases.

  The heat medium from the second expansion valve 22 is input to the evaporator 14. In the evaporator 14, the heat medium exchanges heat with room air and absorbs heat from the room air to cool the room air. This cooled room air is supplied to the passenger compartment as cold air.

  The heat medium output from the evaporator 14 is input to the accumulator 15, and then input to the electric compressor 11 and compressed again, and the heat medium flows through the flow path as described above.

  Next, the operation of the heat pump system during heating will be described with reference to FIG.

  When a heating instruction is input by the occupant, the control unit 10 controls the two-way solenoid valve 23 to be turned on and the three-way solenoid valve 24 to be turned off, and operates the electric compressor 11.

  From the electric compressor 11, the heat medium compressed to a high temperature and high pressure is input to the indoor condenser 12 through the pipe 16. The indoor condenser 12 operates during heating, and the heat medium exchanges heat with the air in the passenger compartment in the indoor condenser 12 to radiate heat. The radiated air is further heated by passing through the PTC heater 19, and the heated indoor air is supplied as warm air into the vehicle interior. In this case, the open / close state is set so that the air mix damper 18 does not face the indoor condenser 12.

  The heat medium that has passed through the indoor condenser 12 flows through the first expansion valve 21 side because the two-way solenoid valve 23 is in the ON state, and is depressurized to decrease the temperature. The decompressed heat medium is input to the outdoor capacitor 13. The heat medium flowing into the outdoor condenser 13 absorbs heat by exchanging heat with outdoor air in the outdoor condenser 13, and the heat medium temperature rises slightly.

  Next, since the three-way solenoid valve 24 is in the OFF state, the heat medium from the outdoor condenser 13 flows into the accumulator 15, and then flows into the electric compressor 11 and is compressed again. Circulate.

  By the way, in the apparatus which air-conditions a vehicle interior using the heat pump system 1 in this way, it heats and cools using a heat cycle by compressing and decompressing a heat medium. For example, after the electric compressor 11 is brought to a high temperature and high pressure state, the pressure is reduced by the expansion valve. In this case, since the state of the pressure of the heat medium greatly differs during cooling and heating, when the air conditioning is switched and each solenoid valve is switched, the pressure state of the heat medium changes and a pressure difference occurs in the heat medium. Since abnormal noise may occur due to the change in the flow of the heat medium due to the pressure difference, it is necessary to suppress this.

  Therefore, in the present embodiment, the control unit 10 performs pressure control at the time of switching the operation state in order to suppress the abnormal noise generated at the time of switching the operation state. Details will be described below.

  When the air-conditioning operation mode is switched, for example, the control unit 10 stops the electric compressor 11 when switching to cooling during heating. At the same time, the valve switching determination is started using the pressure value detected by the pressure detection sensor 31, and the timer is started.

  When the detected pressure value is equal to or lower than the predetermined value or when the timer reaches the predetermined value, the control unit 10 restarts the electric compressor 11 and controls the two-way electromagnetic valve 23 and the three-way electromagnetic valve 24. Switch between on and off states. Thereby, the operation state is switched, and cooling or heating is started.

  As described above, the control unit 10 determines that the pressure difference in the entire heat pump system has decreased if the detected pressure value is equal to or smaller than the predetermined value or the timer reaches the predetermined value, and the electric compressor 11 The operation is switched and the valve is switched to switch the operating state. By stopping the operation of the electric compressor 11 once and then restarting it, noise due to the pressure difference of the heat medium at the time of operation switching can be easily suppressed.

  Specifically, the case where switching to the cooling operation is performed during the heating operation will be described with reference to FIG.

  As shown in FIG. 4, at t = t1, a command for switching the operation mode from heating to cooling is input to the control unit. In this case, the two-way solenoid valve and the three-way solenoid valve are not immediately switched, and the operation of the electric compressor is stopped. During this time, the control unit performs valve switching determination using the pressure value detected by the pressure detection sensor.

  Next, since the pressure value detected by the pressure detection sensor at t = t2 becomes equal to or less than the predetermined value, the operation of the electric compressor is started and the two-way solenoid valve and the three-way solenoid valve are switched. In this case, since the pressure difference of the heat medium in the heat pump system is estimated to be equal to or less than a predetermined value, it is possible to suppress the generation of abnormal noise during valve switching.

  When a command for switching the operation mode from cooling to heating is input to the control unit 10 again at t = t3, the two-way solenoid valve and the three-way solenoid valve are not switched again, and the operation of the electric compressor is stopped. The control unit performs valve switching determination using the pressure value detected by the pressure detection sensor 31, and the pressure value detected by the pressure detection sensor at t = t4 becomes equal to or less than a predetermined value. At the same time, the two-way solenoid valve and the three-way solenoid valve are switched. In this case, since the pressure difference of the heat medium in the heat pump system is equal to or less than a predetermined value, it is possible to suppress the generation of noise during valve switching.

  In the present embodiment, the electromagnetic valve is switched when the pressure difference of the heat medium in the heat pump system becomes a predetermined value or less as described above, so that it is possible to suppress the generation of abnormal noise during valve switching.

  In the present embodiment, it is determined using the pressure of the heat medium whether or not the pressure difference of the heat medium in the heat pump system is small enough to prevent noise, but the present invention is not limited to this. For example, the valve may be switched only by time, that is, by a timer without using pressure. That is, when a predetermined time has elapsed from the time of switching, the valve switching may be performed on the assumption that the pressure difference has decreased.

  In the present embodiment, the control by the control unit 10 described above is performed when switching between cooling and heating, but is not limited to this. The same control may be performed when the air conditioning is turned off during traveling. That is, even when the air conditioning is turned off during traveling, the electric compressor 11 is stopped immediately without switching the electromagnetic valve, and when the pressure value in the heat pump system falls below a predetermined pressure value, Switch. Thereby, generation | occurrence | production of the noise resulting from the pressure difference of the heat medium at the time of valve switching can be suppressed.

  In the present embodiment, only the cooling and heating modes have been described as the air conditioning operation mode, but the present invention is not limited to this. The air conditioning operation mode includes dehumidification and ventilation.

  The vehicle air conditioner according to the present invention can suppress the generation of abnormal noise due to the pressure difference of the heat medium during valve switching. Therefore, it can be used in the vehicle manufacturing field.

DESCRIPTION OF SYMBOLS 1 Heat pump system 10 Control part 11 Electric compressor 12 Indoor condenser 13 Outdoor condenser 14 Evaporator 15 Accumulator 16 Piping 17 Air conditioning housing 18 Air mix damper 19 Heater 21 First expansion valve 22 Second expansion valve 23 Two-way solenoid valve 24 Three-way solenoid valve 31 Pressure sensor I Vehicle air conditioner

Claims (4)

Driven by power supply from the secondary battery, compressing means for compressing the heat medium, pressure reducing means for reducing the pressure of the heat medium, a heat exchanger for exchanging heat between the heat medium and air, and during heating A flow path having a heating path through which the heat medium passes and a cooling path through which the heat medium passes during cooling, a flow path switching valve for changing the path in the flow path according to the air conditioning operation mode, and a flow path switching valve A control unit to be operated,
When the air conditioning operation mode switching command is input, the control unit stops the compression unit and stops the switching operation of the flow path switching valve until the pressure difference in the path becomes a predetermined value or less. An air conditioner for a vehicle.   When the switching command for the air conditioning operation mode is a switching command between the cooling operation and the heating operation, the compression unit is stopped and the flow channel switching is performed until the pressure difference in the flow channel becomes a predetermined value or less. 2. After the valve switching operation is stopped, when the pressure difference in the flow path becomes smaller than a predetermined value, the compression means is operated again and the switching operation of the flow path switching valve is performed. The vehicle air conditioner described. The control unit has pressure measuring means for measuring the pressure in the flow path,
If the pressure measured by the pressure measuring means is equal to or less than a predetermined value, the control unit determines that the pressure difference in the flow path is equal to or less than a predetermined value and performs the switching operation of the flow path switching valve. The vehicle air conditioner according to claim 1 or 2, characterized in that The control unit has time measuring means,
When the air conditioning switching command is input, the control unit starts measurement by the time measuring unit, determines that the measurement time exceeds a predetermined time, and determines that the pressure difference in the flow path is equal to or less than a predetermined value. The vehicle air conditioner according to any one of claims 1 to 3, wherein the switching operation of the flow path switching valve is performed.

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