JP2009166629A - Air conditioner for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner for a vehicle enabling a reduction in power consumption in a bi-level mode during a heating operation. <P>SOLUTION: In this air conditioner for a vehicle, a PTC heater 40 for heating blowing air by electrification and a condenser 22 are installed in an air conditioner case 1. A controller heats the blowing air by the condenser 22 in the bi-level mode during the heating operation, and electrifies the PTC heater 40. To execute a bi-level mode in which the heating of the blowing air by the condenser 22 and the heating of the blowing air by the PTC heater 40 are combined with each other, such an event specific to the bi-level mode that the cooling performance of the condenser 22 is deteriorated as the air quantity passing through the condenser 22 is reduced is improved. Consequently, the power consumption of the entire device can be saved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle air conditioner capable of performing a heating operation using a heat pump refrigeration cycle and a heating operation using an electric auxiliary heating means.

  As an example of a conventional vehicle air conditioner, an apparatus provided with an electric heater that assists heating operation by a heat pump refrigeration cycle and enhances heating performance is known (see Patent Document 1). The apparatus described in Patent Literature 1 can selectively use a heating operation using a heat pump refrigeration cycle and a heating operation using an electric heater. Further, when a heating operation instruction is given, this device first performs a heating operation by a heat pump refrigeration cycle, calculates average power consumption by the heating operation, and calculates power consumption of the heating operation by the electric heater. When the power consumption of the heating operation by the electric heater is smaller than the average power consumption of the heating operation by the heat pump refrigeration cycle, the heating operation by the refrigeration cycle is stopped and the heating operation by the electric heater is performed.

  Furthermore, Patent Document 1 includes a mode in which heating by the refrigeration cycle and heating by an electric heater are used in combination, a heating mode by only the refrigeration cycle, and a heating mode by only an electric heater. An apparatus having a function of switching in response is described.

  On the other hand, the conventional vehicle air conditioner is provided with a bi-level mode that provides air blowing with a temperature difference between the face air outlet and the foot air outlet in order to give the occupant an air-conditioning environment of chills during heating. FIG. 6 shows the flow of air inside the air conditioning unit 100 during the bi-level mode.

  As shown in FIG. 6, in the bi-level mode during heating, cold outside air or the like passes through the evaporator 101 disposed on the upstream side inside the air conditioning unit 100, and then is connected to the foot outlet side passage 104 and the face by the air mix door 102. It is divided into the outlet side passage 105. The air passing through the foot outlet side passage 104 is heated by the condenser 103 and then mixed with the air that has once passed through the face outlet side passage 105, but is mainly blown to the feet of the passenger through the foot outlet 106. The The air passing through the face outlet side passage 105 bypasses the condenser 103 and is mixed with the air once passing through the foot outlet side passage 104, but is mainly blown toward the upper body of the occupant through the face outlet 107. .

At this time, the opening degree of the air mix door 102 is controlled so that the opening area of the foot outlet side passage 104 is smaller than that at the time of max hot in order to increase the temperature difference between the face outlet air and the foot outlet air. .
Japanese Patent Application Laid-Open No. 5-229334

  However, in the bi-level mode, since the amount of air passing through the condenser 103 is smaller than in the case of max hot with good cycle efficiency, the effect of cooling the condenser 103 is reduced, and the refrigerant temperature on the high-pressure side of the refrigeration cycle increases. End up. Therefore, there are problems such as a decrease in cycle efficiency and an increase in power consumption.

  Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide a vehicle air conditioner that can reduce power consumption in a bi-level mode during heating.

In order to achieve the above object, the following technical means are adopted. That is, the first aspect of the invention is the compressor (21) that sucks and discharges the refrigerant, and the heating that heats the air that is discharged from the compressor (21) and flows into the vehicle interior during the heating operation. Heat exchanger (22), decompression device (24) for decompressing the refrigerant cooled by the heating heat exchanger (22) during heating operation, and evaporating the refrigerant decompressed by the decompression device (24) during heating operation An outdoor heat exchanger (25) to be used, and a heat pump refrigeration cycle (20) having a vehicle air conditioner for air conditioning the vehicle interior,
An air inlet (3, 4) is formed on one side, and on the other side, a face outlet opening (12) through which a face blowing air blown toward the passenger's upper body in the passenger compartment passes and toward the passenger's feet A foot blowing opening (11) through which the blown air blowing air passes is formed, and a ventilation path (6) through which the blowing air passes between the air intake ports (3, 4) and the two blowing openings (11, 12). , 7) and an electric auxiliary heating means (40) which is provided inside the air conditioning case (1) and heats the blown air when energized.

  Furthermore, in the first aspect of the present invention, in the bi-level mode for providing the face blowing air and the foot blowing air in the heating operation, the blown air is heated by the heating heat exchanger (22) and the electric auxiliary heating means (40) is energized. It is characterized by doing.

  According to this invention, in the bi-level mode, the heating caused by the reduction of the air passing through the heating heat exchanger by using the heating heat exchanger and the heating of the blown air by the electric auxiliary heating means in combination. It is possible to improve the COP (coefficient of performance) of the refrigeration cycle peculiar to the bi-level mode accompanying the cooling capacity reduction of the heat exchanger for use. That is, the amount of reduction in power consumption accompanying the improvement of the COP of the refrigeration cycle by implementing the present invention exceeds the amount of increase in power consumption by operating the electric auxiliary heating means, and in the bi-level mode Power saving of the entire apparatus can be realized.

  Further, in the bi-level mode of the heating operation, when it is determined that the pressure of the refrigerant discharged by the compressor (21) exceeds a predetermined pressure (P1), blown air is supplied by the heating heat exchanger (22). When heating and energizing the electric auxiliary heating means (40) and determining that the predetermined pressure (P1) is not exceeded, it is preferable to only heat the blown air by the heating heat exchanger (22).

  According to this invention, it can be implemented with high accuracy by determining whether or not the decrease in COP (coefficient of performance) of the refrigeration cycle peculiar to the bilevel mode is at an allowable level based on the refrigerant pressure on the high pressure side of the cycle.

Moreover, the invention which concerns on a vehicle air conditioner does not let the ventilation air taken in from the air intake (3, 4) pass the air which passes a heat exchanger for heating (22), and a heat exchanger for heating (22). Air volume ratio adjusting means (8) for adjusting the air volume ratio is provided.
In the bi-level mode of the heating operation, when it is determined that the air volume of the air passing through the heating heat exchanger (22) does not exceed the predetermined air volume (Q1), the air volume ratio so as to exceed the predetermined air volume (Q1). Adjusting the adjusting means (8) and energizing the electric auxiliary heating means (40);
When it is determined that the predetermined air volume (Q1) is exceeded, it is preferable to only heat the blown air by the heating heat exchanger (22).

  According to the present invention, it can be determined with high accuracy that the COP (coefficient of performance) of the refrigeration cycle peculiar to the bi-level mode is not at an allowable level, and the amount of air blown to the heat exchanger for heating is increased. Since the air volume ratio adjusting means is controlled, it is possible to further promote the reduction in power consumption of the entire vehicle air conditioner.

  Moreover, it is preferable that the electric auxiliary heating means (40) is provided on the downstream side of the blown air with respect to the heating heat exchanger (22). According to the present invention, low temperature air such as outside air can be first introduced into the heating heat exchanger (22), so that the cooling effect of the refrigerant flowing into the heating heat exchanger is increased, and the power consumption of the compressor is increased. Can be further reduced.

  Further, the electric auxiliary heating means (40) is provided on the downstream side of the blown air with respect to the heating heat exchanger (22) and closer to the foot outlet opening (11) than the face outlet opening (12). It is preferable. According to the present invention, the air for cooling the heating heat exchanger tends to increase and the refrigerant pressure in the heating heat exchanger decreases, compared to the operation in the conventional bi-level mode. The COP of the refrigeration cycle can be improved.

  Furthermore, it is preferable that the electric auxiliary heating means (40) is composed of a PTC heater, and since the heat generation efficiency with respect to the energization amount is high, further reduction in power consumption can be expected. Moreover, the mounting space for the heating means can be reduced.

  In addition, the code | symbol in parentheses in each said technical means and each claim of a claim is an example which shows a corresponding relationship with the specific means of embodiment mentioned later.

  A plurality of modes for carrying out the present invention will be described below with reference to the drawings. In each embodiment, parts corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. In the case where only a part of the configuration is described in each embodiment, the other parts of the configuration are the same as those described previously. In addition to the combination of parts specifically described in each embodiment, the embodiments may be partially combined as long as the combination is not particularly troublesome.

(First embodiment)
1st Embodiment which is one Embodiment of this invention is described according to FIGS. 1-4. FIG. 1 is a schematic view showing a configuration of a vehicle air conditioner according to the present embodiment. In FIG. 1, the thick black arrow indicates the refrigerant flow in the cycle during the heating operation, the hatched thick arrow indicates the refrigerant flow in the cycle during the dehumidification operation, and the white thick arrow indicates the cooling operation during the cooling operation. The refrigerant flow in the cycle is shown.

  The vehicle air conditioner of the present embodiment includes a heat pump refrigeration cycle 20 and a PTC heater 40 that is an electric auxiliary heating means, and performs an air conditioning operation using the components shown in FIG. Can be used for electric vehicles. As the electric auxiliary heating means, it is preferable to select a device with low energy loss that can obtain an output (heat generation amount) equivalent to the input with respect to the input (energization amount). In this embodiment, as an example, a PTC heater is used. 40 is adopted.

  An air conditioning case 1 having an air ventilation path inside is provided on the back side of an instrument panel in the front of the passenger compartment. The air conditioning case 1 is formed with an air intake port 3 and an indoor air intake port 4 which are air intakes on one side, and air-conditioned air (hereinafter referred to as conditioned air) blown into the passenger compartment passes through the other side. At least a foot blowout opening 11, a face blowout opening 12, and a differential blowout opening (not shown) are formed.

  The foot blowing opening 11 is an opening through which conditioned air blown to the feet of the passenger in the passenger compartment passes, and the face blowing opening 12 is an opening through which conditioned air blown toward the upper body of the passenger in the passenger compartment passes. The differential outlet is an opening through which conditioned air blown to the inner surface of the windshield of the vehicle passes. Each of these openings is connected to the vehicle interior space via a blowout duct (not shown), and is opened and closed by a blowout opening switching door (not shown) corresponding to the blowout mode. The outside air inlet 3 and the inside air inlet 4 can be opened and closed by an inside / outside air switching door in accordance with the air intake mode.

  The air conditioning case 1 includes, on one side, an inside / outside air switching box including an inside / outside air switching door, and a blower 5 whose suction portion is connected to the outside air suction port 3 and the inside air suction port 4. For example, at the time of heating such as in winter, the anti-fogging effect can be enhanced by introducing outside air having low humidity from the outside air inlet 3 by performing the outside air intake mode, air-conditioning through the ventilation path, and blowing out to the inner surface of the windshield. . Further, by performing the inside air mode, it is possible to reduce the heating load by introducing high temperature inside air from the inside air inlet 4, air-conditioning through the ventilation path, and blowing out toward the feet of the passengers.

  The blower 5 includes a centrifugal multiblade fan (for example, a sirocco fan) and a motor that drives the fan. The periphery of the centrifugal multiblade fan is surrounded by a scroll casing. The air conditioning case 1 includes a plurality of case members, and the material thereof is a resin molded product such as polypropylene.

  The blower outlet of the blower 5 is connected to a ventilation path provided so as to extend in the centrifugal direction of the centrifugal multiblade fan. This ventilation path has a passage extending from the upstream side of the blown air in order of the evaporator 30 as a cooling heat exchanger and a foot extending from the downstream side of the blower air of the evaporator 30 toward the foot outlet opening 11. Air in which the air flowing through the blowout side passage 6 and the face blowout side passage 7 extending from the blower air downstream side of the evaporator 30 toward the face blowout opening 12 and the foot blowout side passage 6 and the face blowout side passage 7 are mixed. And a mixing section. The foot outlet side passage 6 and the face outlet side passage 7 are partitioned by a partition wall 10 provided in the air conditioning case 1 and are arranged so as to run side by side in the transverse direction inside the air conditioning case 1.

  In the ventilation path in the air conditioning case 1 on the downstream side of the blower air with respect to the blower 5, the evaporator 30, the heater core 9, the condenser 22 (heating heat exchanger), and the PTC heater are sequentially arranged from the upstream side to the downstream side. 40 (electric auxiliary heating means) is arranged.

  The evaporator 30 is arrange | positioned so that the whole channel | path immediately after the air blower 5 may be crossed, and all the air blown off from the air blower 5 passes. The evaporator 30 is a cooling heat that dehumidifies and cools the blown air before flowing into the foot blowing side passage 6 and the face blowing side passage 7 by the endothermic action of the refrigerant flowing inside during the cooling operation and the dehumidifying operation. Functions as an exchange.

  The heater core 9 is disposed on the downstream side of the blowing air from the evaporator 30 so that at least the heat transfer portion is located only in the foot outlet side passage 6. During the heating operation, the heater core 9 functions as a heat exchanger that heats the surrounding air by using the heat of the coolant of the vehicle running engine that flows inside.

  The condenser 22 is disposed such that at least the heat transfer portion is located only in the foot outlet side passage 6, and is disposed further downstream of the blowing air than the heater core 9. The condenser 22 functions as a heating heat exchanger that heats the blown air flowing through the foot outlet side passage 6 by the heat radiation action of the refrigerant flowing inside during the heating operation, the dehumidifying operation, and the cooling operation.

  The PTC heater 40 is arranged such that at least its heat transfer portion is located only in the foot outlet side passage 6 and is further arranged downstream of the blower air than the condenser 22. The PTC heater 40 is auxiliary heating means for further heating the blown air flowing through the foot outlet side passage 6 in the bi-level mode during the heating operation. The PTC heater 40 includes an energized heat generating element portion, and generates heat when the energized heat generating element portion is energized to warm the surrounding air.

  This energization heating element portion is configured by fitting a plurality of PTC elements in a resin frame formed of a heat-resistant resin material (for example, 66 nylon, polybutadiene terephthalate, etc.). Moreover, the PTC heater 40 may further include a heat exchange fin portion that transmits heat generated from the energized heat generating element portion. This heat exchange fin part is brazed to a corrugated fin obtained by forming a thin aluminum plate into a corrugated shape and an aluminum plate that keeps the corrugated fin in a certain shape and secures a contact area with the PTC element and the electrode plate. It is constituted by doing.

  In the ventilation path downstream of the evaporator 30 and upstream of the heater core 9 and the condenser 22, the air that has passed through the evaporator 30 is divided into air that passes through the condenser 22 and air that bypasses the condenser 22. An air mix door 8 is provided that can adjust the air volume ratio of these airs by dividing or switching.

  The air mix door 8 can block part or all of the foot outlet side passage 6 and the face outlet side passage 7 by changing the position of the door body by an actuator or the like. The opening degree of the foot outlet side passage 6 by the air mix door 8 is a ratio at which the transverse opening of the foot outlet side passage 6 is opened, and can be adjusted in the range of 0 to 100%. Further, the opening degree of the face blowing side passage 7 by the air mix door 8 is a ratio at which the opening in the transverse direction of the face blowing side passage 7 is opened, and can be adjusted in a range of 0 to 100%.

The heat pump refrigeration cycle 20 uses a change in the state of a refrigerant (for example, R134a, CO _2, etc.) flowing through the cycle to perform cooling, heating, and dehumidification by the cooling evaporator 30 and the heating condenser 22. It can be carried out.

  As shown in FIG. 1, the components of the heat pump refrigeration cycle 20 heat the air by exchanging heat between the compressor 21 that sucks and discharges the refrigerant and the refrigerant and air discharged from the compressor 21 during the heating operation. A condenser 22 that performs the heating operation, an expansion valve 24 that decompresses the refrigerant flowing from the condenser 22 during the heating operation, an outdoor heat exchanger 25 that evaporates the refrigerant decompressed by the expansion valve 24 during the heating operation, An electromagnetic valve 26 provided so as to control the refrigerant flow from the heat exchanger 25 to the compressor 21 and an accumulator 27 for separating the refrigerant from gas and liquid. (Heating operation path (compressor 21 → condenser 22 → three-way valve 23 → expansion valve 24 → branch part 32 → outdoor heat exchanger 25 → electromagnetic valve 26 → accumulator 27 → compressor 21 ). Furthermore, a discharge pressure sensor 41 that detects the pressure of the high-pressure refrigerant discharged by the compressor 21 is provided at the outlet of the compressor 21.

  Further, in the heat pump refrigeration cycle 20, a dehumidifying operation path (expansion valve 24 → branch part 32 → branch part 34 → electromagnetic valve 31 → evaporator 30 → accumulator 27 → compressor 21) connects each component in a ring shape by piping. It is formed by doing. This dehumidifying operation path is a path in which the refrigerant decompressed by the expansion valve 24 during the dehumidifying operation flows into the evaporator 30 without flowing into the outdoor heat exchanger 25 and is then sucked into the compressor 21 via the accumulator 27. is there. A three-way valve 23 is provided in the middle of the pipe connected to the downstream side of the condenser 22.

  Further, the heat pump refrigeration cycle 20 includes a cooling operation path (condenser 22 → three-way valve 23 → branch portion 33 → outdoor heat exchanger 25 → branch portion 32 → branch portion 33 → solenoid valve 28 → expansion valve 29 → evaporator. 30 → accumulator 27 → compressor 21) is formed by connecting each component in an annular shape by piping. In the cooling operation path, the three-way valve 23 is switched to the flow path on the branch portion 33 side so that the refrigerant cooled by exchanging heat with the blown air in the condenser 22 during the cooling operation does not pass through the expansion valve 24. And then flows into the outdoor heat exchanger 25, passes through the flow path opened by the electromagnetic valve 28, is decompressed by the expansion valve 29, flows into the evaporator 30, and is sucked into the compressor 21 via the accumulator 27. Is a route to be done.

  The outdoor heat exchanger 25 is disposed outside the vehicle compartment of the vehicle, and exchanges heat between the outside air forcedly blown by the outdoor fan and the refrigerant. The expansion valve 24 and the expansion valve 29 may be constituted by a fixed expansion valve or a mechanical expansion valve. In the case of the mechanical type, a temperature sensing cylinder is provided, and the refrigerant temperature at the outlet of the outdoor heat exchanger 25 and the outlet of the evaporator 30 is fed back so that the refrigerant evaporates at an appropriate degree of superheat, and the refrigerant flow rate is determined by an appropriate valve opening. Adopts a temperature operation method to control. The compressor 21 is an electric compressor, and an AC voltage whose frequency is adjusted by an inverter is applied to control the rotational speed of the motor. The inverter is supplied with DC power from a vehicle-mounted battery and is controlled by a control device (not shown).

  The control device is a device that controls the air conditioning in the vehicle interior, and includes signals from various switches on the microcomputer and a control panel provided in the front of the vehicle interior, an outside air temperature sensor, an evaporator temperature sensor, a discharge pressure sensor, An input circuit to which a sensor signal is input from a refrigerant temperature sensor or the like at the outlet of the outdoor heat exchanger 25 and an output circuit to send output signals to various actuators are provided. The microcomputer is composed of a memory such as a ROM (read only storage device) and a RAM (read / write storage device), a CPU (central processing unit), and the like, and is based on an operation command transmitted from a control panel or the like. It has various programs used for

  Next, the operation of each operation mode (cooling operation, heating operation, dehumidifying operation) of the vehicle air conditioner according to the above configuration will be described. When the control device activates the compressor 21 when the air conditioner switch of the control panel is ON, and determines the operation mode to be operated from the temperature set by the occupant and the signals received from the various sensors as the cooling operation, the three-way valve The flow direction of 23 is controlled to the branching portion 33 side (broken line in FIG. 1), the electromagnetic valve 28 is opened, and the electromagnetic valve 26 and the electromagnetic valve 31 are closed. Furthermore, since it is a cooling operation, the control device controls the blowout opening switching door so that the blowout mode is the face blowout.

  The flow of the refrigerant during the cooling operation is a flow indicated by a thick thick arrow in FIG. 1, and the high-temperature and high-pressure gas refrigerant discharged from the compressor 21 flows into the condenser 22 and passes through the condenser 22. The air is deprived of heat and cooled, but since the blowing mode is the face blowing, the amount of air passing through the periphery of the condenser 22 is small and the degree of cooling is not large. Then, the refrigerant passes through the branch portion 33 by the three-way valve 23 and flows into the outdoor heat exchanger 25. When the refrigerant passes through the outdoor heat exchanger 25, heat is taken away by the air blown by the outdoor fan, and the mist is cooled. A refrigerant.

  Thereafter, the mist refrigerant passes through the electromagnetic valve 28, is decompressed by the expansion valve 29, flows into the evaporator 30, and absorbs heat from the blown air flowing through the ventilation path in the air conditioning case 1 by the blower 5. The refrigerant is vapor-liquid separated by the accumulator 27 and then sucked into the compressor 21. The cool air absorbed and cooled by the evaporator 30 further travels through the ventilation path and is mainly blown out from the face blowing opening 12 toward the upper body of the occupant to cool the passenger compartment.

  Next, the flow of the refrigerant when the heating operation is performed will be described. When the control device activates the compressor 21 when the air-conditioner switch on the control panel is ON, and determines the mode to be operated from the temperature set by the occupant and signals received from various sensors as the heating operation, the three-way valve 23 The flow direction is controlled to the expansion valve 24 side, the electromagnetic valve 26 is opened, and the electromagnetic valve 28 and the electromagnetic valve 31 are closed. Further, since the control device is in the heating operation, the control device controls the blowout opening switching door so that the blowout mode is the foot blowout or the differential blowout according to the set temperature.

  The flow of the refrigerant during the heating operation is a flow indicated by a thick black arrow in FIG. 1, and the high-temperature and high-pressure gas refrigerant discharged from the compressor 21 flows into the condenser 22 and passes through the condenser 22. The air is deprived of heat and cooled and condensed. Then, the refrigerant flows into the expansion valve 24, and the expansion valve 24 reduces the refrigerant pressure to an appropriate superheat degree at the outlet of the outdoor heat exchanger 25, and the expansion valve 24 is a fixed throttle valve. In some cases, the pressure is reduced to a predetermined low pressure. Thus, the refrigerant decompressed to a low pressure by the expansion valve 24 passes through the branch portion 32 and flows into the outdoor heat exchanger 25, and absorbs heat from the air blown by the outdoor fan when passing through the outdoor heat exchanger 25. Evaporate. The gas refrigerant evaporated in the outdoor heat exchanger 25 passes through the branch portion 33, passes through the electromagnetic valve 26, is separated into gas and liquid by the accumulator 27, and is then sucked into the compressor 21.

  Low-temperature air (for example, outside air in winter) taken in the air-conditioning case 1 during the heating operation passes through the evaporator 30 and then flows mainly through the foot outlet side passage 6 by the air mix door 8 and is heated by the condenser 22. It becomes warm air. When the differential blowing mode during the heating operation is performed, the warm air passes through the condenser 22 and then blows out toward the inner surface of the front window through the differential blowing opening opened by the blowing opening switching door. The Further, when the foot blowing mode of the heating operation is performed, the warm air passes through the condenser 22 and then blows out toward the feet of the occupant through the foot blowing opening 11 opened by the blowing opening switching door. .

  In addition, when the bi-level mode during the heating operation is performed, the low-temperature air taken into the air-conditioning case 1 is turned into air flowing through the foot outlet side passage 6 and the face outlet side passage 7 by the air mix door 8. Divided by appropriate air volume ratio.

  The low-temperature air flowing through the foot outlet side passage 6 becomes hot air heated by the condenser 22 and then heated by the PTC heater 40 to rise in temperature, and flows through the face outlet side passage 7 in the air mixing section. The temperature is adjusted by mixing with low-temperature air and blown out toward the passenger's feet through the foot blowing opening 11. On the other hand, the low temperature air flowing through the face outlet side passage 7 does not pass through the heating means such as the condenser 22 and is not heated. The temperature is adjusted by mixing and blown out through the face blowout opening 12 toward the upper body of the occupant. In this way, air with an appropriate temperature difference (for example, 10 to 15 ° C.) is blown out between the upper body of the occupant and the feet of the occupant. Can be provided. When the target air temperature is high, heating by the heater core 9 may be performed.

  Next, the flow of the refrigerant when the dehumidifying operation is performed will be described. When the control device activates the compressor 21 when the air-conditioner switch on the control panel is ON, and determines the mode to be operated from the temperature set by the occupant and signals received from various sensors as the dehumidifying operation, the three-way valve 23 The flow direction is controlled to the expansion valve 24 side, the electromagnetic valve 31 is opened, and the electromagnetic valve 26 and the electromagnetic valve 28 are closed. Furthermore, since the control device is in the dehumidifying operation, the control device controls the blowout opening switching door so as to mainly perform differential blowout, foot blowout, or rear foot blowout.

  In the dehumidifying operation, the refrigerant flows through the evaporator 30 and the condenser 22, and the blown air in the air conditioning case 1 is first cooled and dehumidified by the evaporator 30, and then heated by the condenser 22 to become warm air. This warm air is blown mainly toward the inner surface of the front window through the differential blower opening, exhibits an anti-fogging effect, and dehumidifies and heats the passenger compartment.

  The flow of the refrigerant during the dehumidifying operation is the flow indicated by the hatched thick arrows in FIG. 1, and the high-temperature and high-pressure gas refrigerant discharged from the compressor 21 flows into the condenser 22 and passes through the condenser 22. The air is deprived of heat and cooled and condensed. Then, the refrigerant is depressurized by the expansion valve 24, and the refrigerant pressure is depressurized to an appropriate superheat degree at the outlet of the expansion valve 24. Thereafter, the refrigerant does not flow into the outdoor heat exchanger 25, and the branch portions 32, 34. And flows into the evaporator 30. Inside the evaporator 30, the blower 5 absorbs heat from the blown air flowing through the ventilation path in the air conditioning case 1 and evaporates, and after being separated into gas and liquid by the accumulator 27, it is sucked into the compressor 21.

  The air that has been absorbed by the evaporator 30 and is cooled and dehumidified further passes through the ventilation path and is heated by the condenser 22. After passing through the condenser 22, this air is blown out toward the inner surface of the front window through the differential blowout opening opened by the blowout opening switching door.

  Next, the flow of the automatic air conditioning operation in the vehicle air conditioner of this embodiment will be described with reference to FIG. FIG. 2 is a flowchart showing the flow of automatic air conditioning operation. First, when an automatic air-conditioning operation command is input to the control device by operating the control panel or the like, air-conditioning control processing is started, and the control device starts a control program stored in a memory such as ROM or RAM and stores it in the RAM. Initialize data to be used.

  The control device reads signals from the control panel and various sensors, calculates a target blowout temperature TAO of air blown into the vehicle interior using a program stored in the ROM, and blower level of the blower 5 (air flow rate of blown air) ) Is calculated (step 1).

  Next, the control device determines whether or not the target outlet temperature TAO calculated in step 1 is equal to or higher than a first predetermined temperature T1 (step 2). The first predetermined temperature T1 is a value stored in advance in a ROM or the like in order to determine whether the foot blowing mode or the bi-level mode is currently appropriate, and is 37 ° C., for example. When it is determined that the target blowing temperature TAO is equal to or higher than the first predetermined temperature T1, the control device executes the foot blowing mode and performs the heating operation using the heat pump refrigeration cycle 20 (step) 3).

  On the contrary, when it is determined that the target blowing temperature TAO is lower than the first predetermined temperature T1, the control device next determines whether or not the target blowing temperature TAO is equal to or higher than the second predetermined temperature T2. (Step 4). The second predetermined temperature T2 is a value smaller than the first predetermined temperature T1, and is stored in advance in a ROM or the like in order to determine whether the bi-level mode or the face blowing mode is currently appropriate. For example, 29 ° C. And when it determines with the target blowing temperature TAO being less than 2nd predetermined temperature T2, a control apparatus performs face blowing mode and implements the above-mentioned air_conditionaing | cooling operation using the heat pump refrigeration cycle 20. FIG. (Step 5).

  Conversely, when it is determined that the target outlet temperature TAO is equal to or higher than the second predetermined temperature T2, the control device executes the heating operation using the heat pump refrigeration cycle 20 in the bi-level mode (step 6). . Note that, in the heating operation in Step 6, when the heating capacity is insufficient even in the heat pump refrigeration cycle 20, the PTC heater 40 or the heater core 9 is operated to perform a process for supplementing the heating capacity.

  Further, the control device determines whether or not the pressure Pd of the high-pressure side refrigerant detected by the discharge pressure sensor 41 exceeds a predetermined pressure P1 (step 61). The predetermined pressure P1 is determined in advance in order to determine whether or not the current high-pressure side refrigerant pressure is a high pressure that reduces the COP (coefficient of performance) of the refrigeration cycle and increases the power consumption of the compressor 21. Is set based on experimental values and experience values. For example, when the refrigerant is R134a, 1.5 MPa is adopted.

  When it is determined that the pressure Pd of the high-pressure side refrigerant does not exceed the predetermined pressure P1, the control device is in a situation where the pressure of the high-pressure side refrigerant is at the allowable level of the cycle efficiency and has not deteriorated yet. The heating operation using the heat pump refrigeration cycle 20 is performed without performing auxiliary heating by the PTC heater 40 (step 62).

  Conversely, if it is determined that the pressure Pd of the high-pressure side refrigerant exceeds the predetermined pressure P1, the control device increases the power consumption because the pressure of the high-pressure side refrigerant exceeds the allowable level of the cycle efficiency. In addition to the heating operation using the heat pump refrigeration cycle 20, the PTC heater 40 is energized to perform auxiliary heating (step 63).

  By the way, in the conventionally known heating operation in which heat is radiated only by the condenser to heat the blown air, the air volume hitting the condenser in the bi-level mode is smaller than that at the maximum hot operation. As a result, the refrigerant pressure on the high-pressure side of the refrigeration cycle is increased and the work of the compressor is increased. This phenomenon was attributed to an increase in power consumption of the compressor and a decrease in COP of the refrigeration cycle.

  Therefore, the automatic air-conditioning operation is controlled so as to increase the air flowing toward the condenser 22 by operating the PTC heater in the bilevel mode of the heating operation, compared to the operation in the conventional bilevel mode. Therefore, the pressure level of the high-pressure side refrigerant is lowered, and there is an effect of reducing the work amount of the compressor with respect to the conventional heating operation. Further, according to the above control of the automatic air-conditioning operation, the entire vehicle air-conditioning apparatus can be used even when the necessary heating capacity can be exhibited only by the heating operation using the heat pump refrigeration cycle 20 without requiring auxiliary heating such as a heater. It is possible to provide the optimum combined heating operation of the heat pump refrigeration cycle 20 and the PTC heater 40 in consideration of the efficiency (the ratio between the heating performance and the power consumption).

  Next, verification of the effect when the control of the automatic air conditioning operation is performed will be described with reference to FIGS. 3 and 4. FIG. 3 is a cycle diagram on the Mollier diagram showing a result of an experiment comparing the combined operation of the PTC heater and the heat pump refrigeration cycle and the operation of only the conventional heat pump refrigeration cycle under predetermined experimental conditions. . FIG. 4 is a graph comparing the power consumption between the combined operation of the PTC heater and the heat pump refrigeration cycle and the operation of only the conventional heat pump refrigeration cycle under the predetermined experimental conditions.

  Of the two cycle diagrams shown on the Mollier diagram of FIG. 3, the solid line (A → B → C → D) is a cycle diagram of a heat pump refrigeration cycle (the above automatic air conditioning operation) operated in combination with a PTC heater, A one-dot chain line (A1-> B1-> C1-> D1) is a cycle diagram of a conventional automatic air-conditioning operation in which only the heat pump refrigeration cycle is operated.

  As shown in FIG. 3, in the automatic air-conditioning operation, a larger amount of air that cools the condenser 22 flows than in the conventional automatic air-conditioning operation, so that the pressure on the high-pressure side is lower than in the conventional cycle diagram. (The solid line BC has a lower pressure than the one-dot chain line B1-C1). Thereby, the work of the compressor in the automatic air-conditioning operation (= iB-iA) is significantly smaller than the work of the compressor in the conventional automatic air-conditioning operation (= iB1-iA1). Regarding the heat radiation amount in the condenser, since there is no large difference between the case of the automatic air conditioning operation (= iB-iC) and the case of the conventional automatic air conditioning operation (= iB1-iC1), the efficiency (coefficient of performance) of the refrigeration cycle is It can be seen that the above-described automatic air-conditioning operation in which the amount of work of the compressor is small is significantly superior.

  Next, the result of comparing the power consumption of the entire vehicle air conditioner will be described. FIG. 4 shows that the power consumption in the automatic air-conditioning operation is smaller than that in the conventional automatic air-conditioning operation. Under certain experimental conditions, the power consumption in the conventional automatic air-conditioning operation exceeds 0.7 kW (power consumption of the compressor), and the power consumption in the automatic air-conditioning operation under the same conditions is less than 0.6 kW (the power consumption of the compressor is about 0. 0). 35 kW and the power consumption of the PTC heater is about 0.25 kW). Thus, the combined use of the operation of the heat pump refrigeration cycle 20 and the operation of the PTC heater 40 in the bi-level mode of the heating operation reduces the power consumption reduction of the compressor 21 due to the improvement of the COP of the refrigeration cycle. The power consumption of the entire vehicle air conditioner can be realized with respect to the operation in which the auxiliary heating by the PTC heater 40 is not performed.

  The vehicle air conditioner of the present embodiment includes a PTC heater 40 that heats the blown air when energized, in addition to the condenser 22, inside the air conditioning case 1. Then, the control device heats the blown air by the condenser 22 during the bi-level mode in the heating operation and energizes the PTC heater 40 to generate heat.

  Thereby, in the bi-level mode of the heating operation, the heating of the blown air by the condenser 22 and the PTC heater 40 is used together, so that the power consumption due to the operation of the PTC heater 40 increases. However, since the power consumption of the PTC heater 40 can be exceeded and the refrigerant pressure on the high pressure side can be reduced compared to that in the conventional bi-level mode (see FIG. 4), even if the heat dissipation in the condenser 22 is at an equivalent level. The amount of work applied by the compressor 21 can be suppressed. Therefore, in the vehicle air conditioner of the present embodiment, when the heating operation is in the bi-level mode, the amount of work applied by the compressor 21 is smaller than that of the conventional vehicle air conditioner, so the coefficient of performance of the refrigeration cycle (COP = condenser) Heat dissipation amount / work amount to be added by the compressor). Therefore, it is possible to improve the phenomenon of the cycle efficiency decrease peculiar to the conventional bi-level mode, and to reduce the power consumption of the entire apparatus.

  Further, in the bilevel mode of the heating operation, the control device heats the blown air by the condenser 22 and determines the PTC heater 40 when the pressure of the refrigerant discharged by the compressor 21 exceeds the predetermined pressure P1. When the energization is performed to further heat the blown air and it is determined that the predetermined pressure P1 is not exceeded, only the blown air is heated by the condenser 22.

  According to this control, it is possible to determine with high accuracy whether or not the decrease in the COP (coefficient of performance) of the refrigeration cycle peculiar to the bi-level mode is at an allowable level.

  Further, since the PTC heater 40 is provided on the downstream side of the blowing air from the condenser 22, low-temperature air such as outside air can be first introduced into the condenser 22, so that the refrigerant flowing into the condenser 22 can be introduced. The cooling effect is increased. Therefore, the power consumption of the compressor 21 can be further reduced. Moreover, since the temperature difference with the air on the condenser 22 side can be made larger than when the PTC heater 40 is provided on the upstream side of the condenser 22, the temperature rise efficiency of the blown air can be improved.

  Further, the size (for example, heat transfer area) of the PTC heater 40 in the ventilation path is set to be smaller than that of the condenser 22, and a part of the air that has passed through the condenser 22 passes through the PTC heater 40. Has been. Further, air heated by passing through the PTC heater 40 in the bi-level mode of the heating operation flows more to the foot blowing opening 11 than to the face blowing opening 12. In other words, the PTC heater 40 is provided on the downstream side of the blowing air from the condenser 22 and at a position closer to the foot blowing opening 11 than the face blowing opening 12.

  According to such a configuration, the opening degree of the air mix door 8 in which the bi-level mode is established is condensed in the automatic air-conditioning operation in which the auxiliary heating by the PTC heater 40 is performed rather than the operation in the conventional bi-level mode. Since the air flowing toward the condenser 22 is controlled to increase, the refrigerant pressure in the condenser 22 is reduced and the work of the compressor is reduced, so that further improvement in COP of the refrigeration cycle can be expected.

(Second Embodiment)
In the second embodiment, another example of the automatic air conditioning operation in the first embodiment will be described with reference to FIG. FIG. 5 is a flowchart showing the flow of the automatic air conditioning operation of the present embodiment. The processing flow of the automatic air-conditioning operation in the present embodiment is different from the processing flow of the automatic air-conditioning operation described in the first embodiment with reference to FIG. The other steps denoted by the same reference numerals are the same as the steps in FIG. Further, each component of the vehicle air conditioner, their operation, and effects are the same as in the first embodiment.

  As shown in FIG. 5, when it is determined that the target blowing temperature TAO is equal to or higher than the second predetermined temperature T2, the control device performs the heating operation using the heat pump refrigeration cycle 20 in step 7 in the bilevel mode. Run with.

  Next, the control device executes a process of calculating the opening degree of the air mix door 8 (the opening ratio of the ventilation path (foot blowing side passage 6) leading to the condenser 22) (step 71). Then, the control device calculates the air volume that is supposed to pass through the condenser 22 by using the blower air volume calculated from the blower level of the blower 5 and the opening degree of the air mix door calculated in step 71, and the calculated condenser 22 It is determined whether the predicted air volume of the air exceeds a predetermined air volume Q1 (step 72). The predetermined air volume Q1 is an air volume stored in advance in a ROM or the like that can predict that the efficiency (coefficient of performance) of the refrigeration cycle will deteriorate if the air volume blown to the condenser 22 is too small and the air volume further decreases. Set based on value and experience. As the predetermined air volume Q1, for example, an air volume of about 20% of the blower level Hi (strong air volume) at the time of max hot is adopted.

  When it is determined that the calculated predicted passage air volume of the condenser 22 exceeds the predetermined air volume Q1, the control device determines that the predicted passage air volume of the condenser 22 is at an allowable level of cycle efficiency and is still The heating operation using the heat pump refrigeration cycle 20 is performed with the opening degree of the air mix door 8 as it is without performing the auxiliary heating by the PTC heater 40 (step 73). .

  On the other hand, when it is determined that the calculated predicted flow rate of the condenser 22 does not exceed the predetermined flow rate Q1, the control device has too little predicted predicted flow rate of the condenser 22 and the cycle efficiency is acceptable. Assuming that the power consumption has increased beyond the level, the opening degree of the air mix door 8 is controlled so that the predicted air volume passing through the condenser 22 exceeds the predetermined air volume Q1 (foot outlet side passage) 6), in addition to the heating operation using the heat pump refrigeration cycle 20, the PTC heater 40 is energized to perform auxiliary heating (step 73).

  The control device according to the vehicle air conditioner of the present embodiment determines that the air volume that is predicted to pass through the condenser 22 in the bi-level mode of the heating operation does not exceed the predetermined air volume Q1. The opening degree of the air mix door 8 is adjusted so that the PTC heater 40 is energized. On the contrary, when it is determined that the predicted passage air volume of the condenser 22 exceeds the predetermined air volume Q1, only the air blown by the condenser 22 is heated.

  According to this control, it can be determined with high accuracy that the COP (coefficient of performance) of the refrigeration cycle peculiar to the bilevel mode is not at an allowable level. Furthermore, since the air mix door 8 is controlled so that the amount of air blown to the condenser 22 is increased, the ability to cool the condenser 22 can be further improved and the work amount of the compressor 21 can be reduced. The power consumption of the entire air conditioner can be further reduced.

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

  For example, although the PTC heater 40 is employed as the electric auxiliary heating means in the above embodiment, the present invention is not limited to this. The electric auxiliary heating means may be any device that can generate heat from a heating element or the like to heat surrounding air or an object when energized.

  Moreover, in the said embodiment, although the PTC heater 40 is arrange | positioned in the downstream of blowing air rather than the condenser 22, even if it arrange | positions in the upstream of blowing air rather than the condenser 22, it is at the time of heating operation. There is no change in the effect of reducing the power consumption in the bi-level mode.

  In the air conditioning case 1 of the above embodiment, the foot blowout opening 11, the face blowout opening 12 and the differential blowout opening are formed on the other side, but a rear foot blowout opening or the like may be formed in addition to this. Air-conditioning air blown to the feet of the passengers in the rear seat passes through the rear foot outlet. Each of these openings formed in the air conditioning case 1 is connected to the vehicle interior space via a blowout duct, and is opened and closed by a blowout opening switching door (not shown) corresponding to the blowout mode. It has become.

It is the schematic which showed the structure of the vehicle air conditioner which concerns on 1st Embodiment. It is the flowchart which showed the flow of the automatic air conditioning driving | operation of the vehicle air conditioner which concerns on 1st Embodiment. It is the cycle figure which showed the verification result which compared the combined use operation of a PTC heater and a heat pump type refrigerating cycle, and the operation of only the conventional heat pump type refrigerating cycle on the Mollier diagram. It is the graph which showed the experimental result which compared the power consumption about the combined operation of a PTC heater and a heat pump refrigerating cycle, and the operation of only the conventional heat pump refrigerating cycle. It is the flowchart which showed the flow of the automatic driving | operation of the vehicle air conditioner which concerns on 2nd Embodiment. In the conventional vehicle air conditioner, it is the schematic which showed the flow of the wind inside the air conditioning unit 100 at the time of bilevel mode.

Explanation of symbols

1 ... Air-conditioning case 3 ... Outside air intake (air intake)
4 ... Inside air intake (air intake)
6 ... Foot outlet side passage (ventilation path)
7… Face outlet side passage (ventilation path)
8 ... Air mix door (air volume ratio adjusting means)
DESCRIPTION OF SYMBOLS 11 ... Foot blowing opening 12 ... Face blowing opening 20 ... Heat pump refrigerating cycle 21 ... Compressor 22 ... Condenser (heat exchanger for heating)
24 ... Expansion valve (pressure reducing device)
25 ... Outdoor heat exchanger 40 ... PTC heater (electric auxiliary heating means)

Claims (6)

A compressor (21) that sucks and discharges the refrigerant, and a heat exchanger (22) that heats the air that is discharged from the compressor (21) and flows into the vehicle interior during heating operation. ), A decompression device (24) that decompresses the refrigerant cooled by the heating heat exchanger (22) during the heating operation, and an outdoor device that evaporates the refrigerant decompressed by the decompression device (24) during the heating operation. A vehicle air conditioner that uses a heat pump refrigeration cycle (20) having a heat exchanger (25) to adjust the air inside the vehicle compartment,
An air inlet (3, 4) is formed on one side, and on the other side, a face outlet opening (12) through which a face blowing air blown toward the upper body of an occupant in the passenger compartment passes and toward the feet of the occupant The foot blowing opening (11) through which the foot blowing air blown is passed is formed, and the ventilation air passes through the air intake (3, 4) and the two blowing openings (11, 12). An air conditioning case (1) having a path (6, 7);
An electric auxiliary heating means (40) which is provided inside the air conditioning case (1) and heats the blown air when energized;
With
In the bi-level mode for providing the face blowing air and the foot blowing air in the heating operation, the blowing air is heated by the heating heat exchanger (22) and the electric auxiliary heating means (40) is energized. An air conditioner for a vehicle. In the bi-level mode of the heating operation,
When it is determined that the pressure of the refrigerant discharged by the compressor (21) exceeds a predetermined pressure (P1), the blowing air is heated by the heating heat exchanger (22) and the electric auxiliary heating is performed. Energizing means (40),
The vehicle air conditioner according to claim 1, wherein when it is determined that the predetermined pressure (P1) is not exceeded, only the blown air is heated by the heating heat exchanger (22). The blown air taken in from the air intake port (3, 4) is divided into air that passes through the heating heat exchanger (22) and air that does not pass through the heating heat exchanger (22), and its air volume. An air volume ratio adjusting means (8) for adjusting the ratio;
In the bi-level mode of the heating operation,
When it is determined that the air volume of the air passing through the heating heat exchanger (22) does not exceed the predetermined air volume (Q1), the air volume ratio adjusting means (8) is set so as to exceed the predetermined air volume (Q1). Adjusting and energizing the electric auxiliary heating means (40),
2. The vehicle air conditioner according to claim 1, wherein, when it is determined that the predetermined air volume (Q1) is exceeded, only the blown air is heated by the heating heat exchanger (22).   The said electric auxiliary heating means (40) is provided in the said ventilation air downstream rather than the said heat exchanger for heating (22), The Claim 1 characterized by the above-mentioned. Vehicle air conditioner.   Furthermore, the said electric auxiliary | assistant heating means (40) is provided in the position close | similar to the said foot blowing opening (11) rather than the said face blowing opening (12), The vehicle air conditioning of Claim 4 characterized by the above-mentioned. apparatus.   The vehicle air conditioner according to any one of claims 1 to 5, wherein the electric auxiliary heating means (40) comprises a PTC heater.

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