JP4133084B2 - Air conditioner for vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dual type vehicle air conditioner having a first air conditioning unit for air conditioning a front seat side space and a second air conditioning unit for air conditioning a rear seat side space.
[0002]
[Prior art]
In particular, in a vehicle having a large interior space, a so-called dual type vehicle air conditioner that uses a separate air conditioning unit to air-condition the front seat side space and the rear seat side space is employed in order to obtain a comfortable air conditioning state. Yes.
[0003]
When vehicle interior heating is performed using such a vehicle air conditioner, for example, a heater for supplying engine cooling water to the front seat air conditioning unit and the rear seat air conditioning unit is provided, and each air is heated by a blower fan. There is one configured to heat the interior by blowing air to the chamber.
[0004]
However, in recent vehicles, the combustion efficiency of the engine is improved, so that a sufficient amount of heat cannot be obtained from the cooling water. Especially when the engine is started when the outside air temperature is low, the front seat side space and the rear It is difficult to quickly heat both air in the seat side space.
[0005]
Therefore, in addition to heating with a heater using cooling water, driving a vehicle air conditioner, heating the air using the condensation heat of the refrigerant condensed by the heat exchanger (heat pump), Some employ a method of heating air using an electric heater, a combustion heater or the like as an auxiliary heat source.
[0006]
[Problems to be solved by the invention]
By the way, when heating by a heat pump at low temperatures, the heating capacity may be insufficient in the initial stage of heating. For this reason, it is necessary to stop the operation of the blower and wait until the temperature of the refrigerant sufficiently rises. During this time, the heating operation is stopped and rapid heating cannot be performed.
[0007]
In order to eliminate such inconvenience, the refrigerant discharged from the compressor bypasses the main condenser and is supplied to a sub-condenser connected in series with the evaporator (for example, Japanese Patent Laid-Open No. 9-202129). And a method of heating a refrigerant with a condenser connected in series to an evaporator and an auxiliary heater using engine cooling water (for example, see Japanese Patent Laid-Open No. 10-86648). Yes.
[0008]
However, in these methods, since the condenser and the evaporator are connected in series, the resistance in the cycle pipe is large and the volume in the pipe is large. Therefore, when the refrigerant is heated in the early stage of heating at a low temperature, the rate of temperature rise of the refrigerant is slow. As a result, it is desired that the standby time for stopping the operation of the blower is relatively long and that heating is performed more rapidly.
[0009]
The present invention has been made in consideration of such problems, and in a dual-type vehicle air conditioner, a vehicle that enables rapid heating by rapidly raising the temperature of a refrigerant during heating operation at a low temperature. The purpose is to provide an air conditioner for a vehicle.
[0010]
[Means for Solving the Problems]
A vehicle air conditioner according to the present invention is a vehicle air conditioner having a first air conditioning unit that air-conditions a first space and a second air conditioning unit that air-conditions a second space. , A first electromagnetic on-off valve and a second electromagnetic on-off valve respectively provided in the branched pipe of the discharge port of the compressor, and a first condensing refrigerant supplied via the first electromagnetic on-off valve A second condenser for condensing the refrigerant supplied via the second electromagnetic on-off valve, and the second electromagnetic on-off valve provided between the second electromagnetic on-off valve and the second condenser. A direction switching valve for switching a delivery destination of the refrigerant fed from the second condenser to an inlet side pipe line or a pipe line downstream from the outlet side of the second condenser; and the first condenser vessel only A first expansion valve and a second expansion valve for expanding the refrigerant condensed by the first expansion valve; a first evaporator for evaporating the refrigerant expanded by the first expansion valve; and a first evaporator for evaporating the refrigerant expanded by the second expansion valve. 2 evaporators, a heater that heats air with hot water heated by an engine, and a control unit that performs overall control, wherein the first air conditioning unit includes the first expansion valve and the first evaporation. And the second air conditioning unit includes the second expansion valve, the second evaporator, and the second condenser. When the outside air temperature is lower than a predetermined temperature, the control unit switches the direction switching valve so that the refrigerant flows into a pipe line downstream from the outlet side of the second condenser, and the second electromagnetic opening / closing valve. Is communicated to perform initial heating, and then the directional control valve is switched so that the refrigerant flows into the pipe line on the inlet side of the second condenser to shift from the initial heating operation to the normal heating operation. It is characterized by that.
[0011]
As described above, the refrigerant supplied through the second electromagnetic opening / closing valve is switched to either the inlet side pipeline of the second condenser or the downstream pipeline from the outlet side by the direction switching valve. The refrigerant delivery destination can be selected according to the operating state of the vehicle air conditioner. Since the first evaporator and the second evaporator are in a non-series circuit with the second condenser, the volume in the cycle during the heating operation using the second condenser is small.
[0013]
By doing so, since the refrigerant can be circulated around the first condenser and the second condenser in the initial stage of the heating operation at a low temperature, the volume of the cycle path is reduced, and the pipe line Resistance can be reduced. Accordingly, it is possible to increase the temperature of the refrigerant rapidly by increasing the circulation speed of the refrigerant.
[0014]
Further, an auxiliary heater for heating the refrigerant may be provided between the compressor and the second condenser.
[0015]
The refrigerant is supplied from the compressor to the second condenser, and the second condenser is All Refrigerant But As long as it does not liquefy Some refrigerant Heating may be performed by heat exchange by condensation.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, a preferred embodiment of a vehicle air conditioner according to the present invention will be described and described with reference to FIGS.
[0017]
As shown in FIG. 1, the vehicle air conditioner 10 according to the first embodiment includes a front seat air conditioning unit (first air conditioning unit) 70 that performs air conditioning on the front seat (first space) side and a rear seat (first air conditioning unit). It is a dual type air conditioner having a rear seat side air conditioning unit (second air conditioning unit) 78 that performs air conditioning on the (2 space) side.
[0018]
The vehicle air conditioner 10 is driven by a vehicle engine 12 via an electromagnetic clutch 14, and a compressor (also referred to as a compressor) 16 that sucks and compresses refrigerant, and a first electromagnetic wave provided in an outlet pipe of the compressor 16. The on-off valve 18 and the second electromagnetic on-off valve 20, and a first condenser (also referred to as a condenser) 22 that condenses the refrigerant flowing in via the first electromagnetic on-off valve 18 are included. The electromagnetic clutch 14 is turned on (connected state) during operation of the vehicle air conditioner 10.
[0019]
The vehicle air conditioner 10 is provided downstream of the first condenser 22, and is provided at a receiver 30 that separates the gas-liquid refrigerant and sends out only the liquid refrigerant, and at two branch destinations downstream of the receiver 30. The first and second expansion valves (also referred to as expansion valves) 32 and 34 for expanding the refrigerant, and the refrigerant expanded by the first expansion valve 32 and the second expansion valve 34 evaporate, and the passing air is generated by the heat of evaporation and evaporation. First and second evaporators (also referred to as evaporators) 36 and 38 for cooling the above. The refrigerant that has passed through the first evaporator 36 and the second evaporator 38 is supplied to the low-pressure line 44 via check valves 40 and 42 that prevent backflow. The refrigerant supplied to the low-pressure line 44 is prevented from flowing back by the check valves 40, 42, 60.
[0020]
Further, the vehicle air conditioner 10 is connected in parallel with a heater (also referred to as a heater core) 46 that heats air with hot water heated by the engine 12 and heats the refrigerant in the low-pressure line 44. And an auxiliary heater 48. The refrigerant that has passed through the auxiliary heater 48 is sucked into the compressor 16. A cock 47 that can be opened and closed is provided on the inlet side of the heater 46.
[0021]
Furthermore, the vehicle air conditioner 10 includes a direction switching valve 50 that switches the direction of the delivery destination of the refrigerant supplied from the second electromagnetic opening / closing valve 20 to two directions. A first direction pipe (inlet side pipe) 51 on the secondary side of the direction switching valve 50 is connected to an inlet of a second condenser 52 that condenses the refrigerant. A second directional pipe (second pipe downstream from the outlet side) 54 on the secondary side of the direction switching valve 50 is connected to the inlet side of the pressure reducing device 56 that reduces the pressure of the refrigerant. The outlet side of the second condenser 52 joins the second directional pipe 54 and is connected to the pressure reducing device 56.
[0022]
On the outlet side of the decompression device 56, a check valve 60 that prevents the reverse flow of the refrigerant to the decompression device 56 is provided, and the decompression device 56 is connected to the low-pressure line 44 via the check valve 60.
[0023]
A third electromagnetic opening / closing valve 49 is provided on the inlet side of the auxiliary heater 48. In the vicinity of the first condenser 22, a condenser fan 64 that blows heat radiation air to the first condenser 22 is provided.
[0024]
A temperature sensor 66 for measuring the exhaust temperature of the first condenser 22 is provided in the vicinity of the first condenser 22. A water temperature sensor 68 that measures the temperature of the hot water in the pipes is provided at the junction of the outlet side pipes of the heater 46 and the auxiliary heater 48. A temperature sensor 69 for measuring the air temperature is provided in the vicinity of the second condenser 52.
[0025]
The first evaporator 36 and the heater 46 are included in the front seat air conditioning unit 70 and are disposed in an air flow path 72 such as a duct. A first blower 74 that blows air to the first evaporator 36 and / or the heater 46 is provided in the air flow path 72. The first blower 74 selectively supplies and sends outside air or inside air, and the supplied air is cooled and dehumidified by the first evaporator 36. Part or all of the air that has passed through the first evaporator 36 is selectively guided to the heater by the air mix door 76. The air guided to the heater 46 is heated by exchanging heat with the hot water in the heater 46. The air conditioned by the first evaporator 36 and the heater 46 is blown toward the windshield and / or the front seat passenger in the passenger compartment.
[0026]
The second evaporator 38 and the second condenser 52 are included in the rear seat air conditioning unit 78 and are disposed in an air flow path 80 such as a duct. A second blower 82 that blows air to the second evaporator 38 and / or the second condenser 52 is provided in the air flow path 80. The second blower 82 selectively supplies and sends outside air or inside air, and the supplied air is cooled and dehumidified by the second evaporator 38. Part or all of the air that has passed through the second evaporator 38 is selectively guided to the second condenser 52 by the air mix door 84. The air guided to the second condenser 52 is heated by exchanging heat with the refrigerant in the second condenser 52. The action of the second condenser 52 is the action of a heat pump that radiates the heat of the refrigerant compressed and heated by the compressor 16. The air conditioned by the second evaporator 38 and the second condenser 52 is blown toward the rear seat passenger in the vehicle interior.
[0027]
Moreover, the vehicle air conditioner 10 includes a control unit 86 as a control unit that performs a program operation using a microcomputer or the like.
[0028]
Measurement values of the temperature sensor 66, the water temperature sensor 68 and the temperature sensor 69 are input to the control unit 86. An outside air temperature sensor 88 is connected to the controller 86, and the outside air temperature sensor 88 detects the temperature outside the passenger compartment. Electromagnetic clutch 14, first electromagnetic on-off valve 18, second electromagnetic on-off valve 20, third electromagnetic on-off valve 49, direction switching valve 50, first blower 74, second blower 82, condenser fan 64, air mix doors 76, 84 Such an electric device is controlled by the control unit 86. In FIG. 1, input / output signal lines to the controller 86 are omitted. The same applies to FIGS. 3 and 4 described later.
[0029]
Next, a procedure for air-conditioning the vehicle interior by the vehicle air-conditioning apparatus 10 configured as described above will be described, particularly a heating operation of the rear seat space. The following procedure is basically controlled by the control unit 86.
[0030]
The heating operation by the vehicle air conditioner 10 can be divided into a normal heating operation, a dehumidifying heating operation, and an initial heating operation at a low temperature start.
[0031]
When the passenger operates a switch (not shown), the control unit 86 performs the heating operation.
[0032]
When the outside air is in a low temperature state and the vehicle interior is rapidly heated, the vehicle air conditioner 10 needs to raise the refrigerant temperature in the cycle to an appropriate temperature, and performs these operations as an initial heating operation. The condition for performing the initial heating operation is, for example, that the outside air temperature is 0 [° C.] or less.
[0033]
The control unit 86 sets each device in the circuit as the initial heating operation as follows. That is, the 1st electromagnetic on-off valve 18 is interrupted | blocked and the 2nd electromagnetic on-off valve 20 and the 3rd electromagnetic on-off valve 49 are connected. The direction switching valve 50 is switched to the second direction pipeline 54 side. The second blower 82 and the condenser fan 64 are stopped. The air mix door 84 is set downward in FIG.
[0034]
By doing so, the refrigerant discharged from the compressor 16 passes through the second electromagnetic on-off valve 20, the direction switching valve 50, and the second direction pipe 54 and is guided to the pressure reducing device 56. The refrigerant is decompressed by the decompression device 56 and then flows into the auxiliary heater 48 via the check valve 60 and the low pressure pipe 44.
[0035]
Since the third electromagnetic opening / closing valve 49 is in communication, the engine coolant is supplied to the auxiliary heater 48. The refrigerant flowing into the auxiliary heater 48 exchanges heat with engine cooling water. The temperature of the engine cooling water gradually increases after the engine 12 is started, and the auxiliary heater 48 heats the refrigerant.
[0036]
In the initial heating operation, the suction refrigerant can be boosted in temperature by the heat exchange action of the auxiliary heater 48, and the flow of the return refrigerant can be promoted to increase the efficiency of the compressor 16. Moreover, since the refrigerant cycle at this time passes only through the compressor 16, the second electromagnetic on-off valve 20, the direction switching valve 50, the pressure reducing device 56, the check valve 60 and the auxiliary heater 48, the cycle path is short. Further, in this cycle, the first condenser 22, the second condenser 52, the first evaporator 36, the second evaporator 38 and the like having a relatively large pipe line resistance are not passed, The pipe resistances of the second electromagnetic switching valve 20, the direction switching valve 50, and the check valve 60 are small enough to be ignored. Therefore, the pipe resistance of this cycle is very small.
[0037]
Furthermore, since it does not pass through the first condenser 22 having a relatively large volume, the volume in the cycle is small. The small volume means that the heat capacity is small.
[0038]
Thus, the refrigerant cycle in the initial heating operation has a short path, a small volume, and a very small pipe resistance, so that the refrigerant circulation speed is high. Therefore, heat exchange in the auxiliary heater 48 is performed efficiently. Moreover, since the heat capacity is small, the temperature of the refrigerant rises rapidly.
[0039]
Further, since the first electromagnetic on-off valve 18 is blocked, the refrigerant is blocked from the first condenser 22, and the first evaporator 36 connected to the downstream side of the first condenser 22. And the second evaporator 38 does not work. That is, the cooling process is not performed.
[0040]
Next, the control unit 86 detects that the measured values of the water temperature sensor 68 and the temperature sensor 69 have reached predetermined temperatures, and the initial heating operation is terminated.
[0041]
Specifically, it is detected that the measured value of the temperature sensor 69, that is, the temperature in the vicinity of the second condenser 52 has reached, for example, 30 [° C.], and the direction switching valve 50 is connected to the first direction pipe 51. And the second blower 82 is driven. Further, the measured value of the water temperature sensor 68, that is, the temperature of the engine cooling water is detected to reach 60 [° C.], for example, and the third electromagnetic on-off valve 49 is shut off. The second electromagnetic opening / closing valve 20 maintains the communication state.
[0042]
The fact that the temperature in the vicinity of the second condenser 52 has reached 30 [° C.] means that the temperature of the air is sufficient for heating and the engine coolant has reached 60 [° C.]. Means that the temperature of the refrigerant is suitable for heating. Therefore, the initial heating operation can be terminated when these conditions are satisfied.
[0043]
Thus, by shifting from the initial heating operation to the normal heating operation, the refrigerant discharged from the compressor 16 flows into the second condenser 52 through the direction switching valve 50 and passes through the second condenser 52. Then, it is guided to the decompression device 56.
[0044]
Further, since the air is blown by the second blower 82, in the second condenser 52, the refrigerant is condensed, dissipated heat, and the vehicle interior can be heated. In particular, since both the air temperature and the refrigerant temperature near the second condenser 52 are sufficiently raised, a sufficient heating effect is achieved.
[0045]
In the normal heating operation, the refrigerant that has been compressed by the isentropic change in the compressor 16 to become high temperature and high pressure is supplied to the second condenser 52 through the second electromagnetic on-off valve 20 and the direction switching valve 50. In the second condenser 52, wind is received from the second blower 82, and the refrigerant is condensed and dissipated as long as it is not liquefied. The vehicle interior is heated by this heat radiation. The refrigerant flowing out of the second condenser 52 is decompressed by the decompression device 56 and then sucked into the compressor 16 via the auxiliary heater 48.
[0046]
As shown in FIG. 2, the cycle line 92 of the heat cycle in the normal heating operation is set in a so-called superheat region on the higher enthalpy side than the saturated vapor line 90 of the Mollier diagram. This is the refrigerant in the second condenser 52 (Part of the vapor is liquefied and compressed to a saturated state where it coexists with the vapor.) It depends.
[0047]
In this normal heating operation, it is not necessary to evaporate the refrigerant when returning to the compressor 16 and does not pass through the second evaporator 38, so that the volume in the cycle can be reduced. In this heat cycle, since the refrigerant is used in a gaseous state, the compressor 16 does not cause liquid compression.
[0048]
In the normal heating operation, since the third electromagnetic opening / closing valve 49 is shut off, the auxiliary heater 48 does not perform heat exchange with the refrigerant, thereby preventing excessive heating of the refrigerant. Therefore, deterioration or internal breakage of the compressor 16 due to excessive rise in the refrigerant temperature can be prevented.
[0049]
Further, when the controller 86 detects a decrease in heating capacity, the third electromagnetic opening / closing valve 49 may be communicated to heat the refrigerant by the auxiliary heater 48. The heat cycle in this case becomes a cycle line 94 indicated by a broken line, and the heating capacity is improved according to the enthalpy difference Δh.
[0050]
In the heat cycle in the normal heating operation, since the refrigerant does not pass through the second evaporator 38, the air in the air flow path 80 is not unnecessarily cooled, and the cycle path is short. Therefore, the heat cycle conduit is simplified and the installation space is reduced. This is particularly effective for a dual-type air conditioning system in which two units, the front seat air conditioning unit 70 and the rear seat air conditioning unit 78, need to be mounted.
[0051]
When the detected value of the temperature sensor 69 becomes excessive, the direction switching valve 50 may be switched to the second direction conduit 54 side, or the electromagnetic clutch 14 may be turned off to temporarily stop the heating process.
[0052]
The heating operation of the front seat air conditioning unit 70 can be performed separately from the heating operation in the rear seat air conditioning unit 78 by driving the first blower 74 and communicating the cock 47.
[0053]
Next, a procedure for performing dehumidifying heating by the vehicle air conditioner 10 will be described.
[0054]
When a passenger operates a switch (not shown) to perform dehumidifying heating, the control unit 86 causes the first electromagnetic on-off valve 18 and the second electromagnetic on-off valve 20 to communicate with each other and sets the direction switching valve 50 to the first mode. Switch to the direction pipe 51 side. The refrigerant discharged from the compressor 16 flows into both the first electromagnetic on-off valve 18 and the second electromagnetic on-off valve 20. The air mix door 84 is set to an appropriate position from the upward position to the downward position in FIG. 1 according to the set temperature, and performs so-called air mixing. Further, the condenser fan 64 and the second blower 82 are driven.
[0055]
A portion of the refrigerant discharged from the compressor 16 that has flowed into the second electromagnetic opening / closing valve 20 is guided to the second condenser 52, and heats the air passing through the air flow path 80 by a heat pump action.
[0056]
On the other hand, the portion of the refrigerant discharged from the compressor 16 that has flowed into the first electromagnetic on-off valve 18 passes through the first electromagnetic on-off valve 18 and then flows into the first condenser 22. Since the condenser fan 64 is driven, the refrigerant condenses and dissipates heat in the first condenser 22. The refrigerant condensed in the first condenser 22 is liquefied.
[0057]
The liquefied refrigerant is guided to the second expansion valve 34 (and the first expansion valve 32) via the receiver 30. The refrigerant expanded by the second expansion valve 34 is in a gas-liquid mixed state and flows into the second evaporator 38. In the second evaporator 38, the refrigerant in the gas-liquid mixed state evaporates by receiving wind from the second blower 82 and becomes gas. At this time, the air passing through the air flow path 80 is cooled and dehumidified by the heat of vaporization accompanying evaporation.
[0058]
The vaporized refrigerant passes through the check valve 42 and enters the low-pressure line 44, and merges with the refrigerant passing through the check valve 60. The refrigerant in the low-pressure line 44 passes through the auxiliary heater 48, reaches the suction port of the compressor 16, and is compressed by the compressor 16.
[0059]
In this way, while the refrigerant circulates, the air passing through the air flow path 80 is cooled, dehumidified, and heated. On the other hand, the heating capacity in the second condenser 52 is set larger than the cooling capacity in the second evaporator 38 as an absolute value. As a result, the air passing through the air flow path 80 is dehumidified and heated.
[0060]
Moreover, you may make the 3rd electromagnetic on-off valve 49 connect, and may operate the auxiliary heater 48 as needed.
[0061]
The heat cycle formed by the second electromagnetic opening / closing valve 20, the second expansion valve 34, and the second evaporator 38 is represented by a cycle line 96 as shown in FIG.
[0062]
In the vehicle air conditioner 10, the first electromagnetic switching valve 18 and the second electromagnetic switching valve 20 are communicated, and the dehumidification is performed by switching the direction switching valve 50 to the first direction pipe 51 side. it can. Furthermore, the 2nd condenser 52 becomes ineffective by interrupting | blocking the 2nd electromagnetic on-off valve 20. FIG. Therefore, the air passing through the air flow path 80 is cooled, so that the vehicle interior can be cooled as a result.
[0063]
In addition, about the dehumidification heating of the front seat side air conditioning unit 70, it is substantially the same as the rear seat side air conditioning unit 78 by operating the 1st evaporator 36, the heater 46, the 1st air blower 74, and the air mix door 76, respectively. Can be done.
[0064]
Next, two modified examples of the vehicle air conditioner 10 according to the present embodiment will be described. The vehicle air conditioner according to these two modified examples has substantially the same configuration as the vehicle air conditioner 10, and the same portions are denoted by the same reference numerals and detailed description thereof is omitted.
[0065]
As shown in FIG. 3, the vehicle air conditioner 100 according to the first modification includes an electric heater 102 instead of the auxiliary heater 48 in the vehicle air conditioner 10. The vehicle air conditioner 100 includes a pressure sensor 104 on the downstream side of the second electromagnetic opening / closing valve 20. The electric heater 102 has a function of heating the refrigerant under the control of the control unit 86. As the electric heater 102, for example, a heater that generates heat by resistance using electric power of a battery or an alternator (not shown) may be used.
[0066]
The pressure sensor 104 measures the pressure in the connected pipeline, and outputs the measurement value to the control unit 86.
[0067]
Similar to the vehicle air conditioner 10, the vehicle air conditioner 100 performs an initial heating operation and a normal heating operation during the heating operation when the outside air is at a low temperature.
[0068]
During the initial heating operation in the vehicle air conditioner 100, the refrigerant can be quickly raised to an appropriate temperature by heating the refrigerant with the electric heater 102. In particular, since the electric heater 102 does not use engine cooling water, the temperature of the refrigerant can be reliably increased without being affected by the temperature of the engine 12.
[0069]
Since the pressure in the pipe line increases as the refrigerant temperature rises, the refrigerant temperature can be estimated from the pressure value indicated by the pressure sensor 104. Therefore, when the pressure value indicated by the pressure sensor 104 becomes, for example, 0.5 [MPa], it can be determined that the temperature of the refrigerant has reached an appropriate temperature, and the water temperature sensor 68 reaches 60 [° C.]. Can be used as an alternative.
[0070]
Accordingly, it is detected that the measured value of the temperature sensor 69 has reached 30 [° C.], the direction switching valve 50 is switched to the first direction pipe 51 and the second blower 82 is driven, and the pressure sensor 104 When the measured value reaches 0.5 [MPa], the third electromagnetic on-off valve 49 is shut off. At this point, the initial heating operation can be terminated and the normal heating operation can be performed.
[0071]
The normal heating operation and the dehumidifying heating operation may be performed in the same manner as the vehicle air conditioner 10. Heating of the front seat air conditioning unit 70 can be performed by the heater 46 separately from the heating of the rear seat side space.
[0072]
Next, as shown in FIG. 4, the vehicle air conditioner 110 according to the second modification is provided with an electric expansion valve 112 instead of the pressure reducing device 56 in the vehicle air conditioner 10. The vehicle air conditioner 110 includes an accumulator (also referred to as a gas-liquid separator) 114 provided on the upstream side of the compressor 16.
[0073]
The electric expansion valve 112 is a valve capable of continuously adjusting the throttle opening of the pipe line under the control of the control unit 86. As shown in FIG. 5, the throttle opening degree of the electric expansion valve 112 is substantially fully opened when the temperature detected by the temperature sensor 69 is low, and acts to reduce the opening degree of the pipeline as the temperature rises. In addition, the throttle opening is kept constant at 30 [° C.] or more.
[0074]
The accumulator 114 has a function of storing the liquefied refrigerant therein and supplying only the vaporized refrigerant to the compressor 16.
[0075]
Similar to the vehicle air conditioner 10, the vehicle air conditioner 110 performs an initial heating operation and a normal heating operation during the heating operation when the outside air temperature is low.
[0076]
In the initial heating operation, the vehicle air conditioner 110 shuts off the first electromagnetic on-off valve 18 and causes the second electromagnetic on-off valve 20 and the third electromagnetic on-off valve 49 to communicate with each other. Further, the direction switching valve 50 is switched to the first direction pipe 51 side.
[0077]
In the initial stage of the initial heating operation, since the outside air is at a low temperature, the throttle opening (see FIG. 5) of the electric expansion valve 112 is approximately 100 [%]. Therefore, the pipe line resistance in this portion is very small, and the refrigerant can be circulated more efficiently.
[0078]
When the initial heating operation is performed, the refrigerant is heated by the action of the compressor 16 and the auxiliary heater 48, so that the temperature of the refrigerant rises. Accordingly, the temperature detected by the temperature sensor 69 provided in the vicinity of the second condenser 52 also increases.
[0079]
Since the measurement value detected by the temperature sensor 69 is input to the control unit 86, the throttle opening degree of the electric expansion valve 112 is adjusted based on this measurement value (see FIG. 5). Since the throttle opening degree of the electric expansion valve 112 is set so as to decrease as the measured value detected by the temperature sensor 69 increases, the electric expansion valve 112 increases as the refrigerant temperature rises during the initial heating operation. The refrigerant is gradually depressurized on the downstream side.
[0080]
When the measured value of the temperature sensor 69 is 30 [° C.] or more, the throttle opening degree of the electric expansion valve 112 is sufficiently narrow, and the refrigerant is sufficiently decompressed. Therefore, in this state, substantially the same cycle operation as the cycle line 92 of the heat cycle shown in FIG. 2 can be performed.
[0081]
In this way, the throttle opening is continuously adjusted between the low temperature and the appropriate heating temperature, so that the refrigerant circulation amount is always set to an appropriate amount.
[0082]
Since the pressure in the pipe line increases as the refrigerant temperature rises, the refrigerant temperature can be estimated from the pressure value indicated by the pressure sensor 104. Accordingly, it can be determined that the temperature of the refrigerant has reached an appropriate temperature when the pressure value indicated by the pressure sensor 104 reaches, for example, 0.5 [MPa].
[0083]
Therefore, in the vehicle air conditioner 110 according to the second modification, the measured value of the temperature sensor 69 reaches 30 [° C.] and the measured value of the pressure sensor 104 reaches 0.5 [MPa]. It can detect and can complete | finish initial heating operation and can transfer to normal heating operation. The normal heating operation may be performed in the same manner as the vehicle air conditioners 10 and 100.
[0084]
Further, in the vehicle air conditioner 110, the action of the accumulator 114 can prevent internal deterioration such as an oil cleaning (degreasing) state in the compressor 16 and liquid compression, and improve toughness during low temperature operation. . In particular, when the throttle opening of the electric expansion valve 112 is large and the refrigerant does not expand so much, it is assumed that some liquid is mixed in the refrigerant because the degree of expansion is small. Thus, even when the liquid is mixed in the refrigerant, the accumulator 114 can prevent the liquid from being fed into the compressor 16.
[0085]
The pressure sensor 104 may use a pressure switch whose contact is switched at 0.5 [MPa], and the switching of the contact of the pressure switch may be used as the end condition of the initial heating operation.
[0086]
The vehicle air conditioners 10, 100, 110 according to the present embodiment and the respective modifications have been described as air mix type air conditioners, but are applied to reheat type air conditioners without the air mix doors 76 and 84. May be.
[0087]
Separate electromagnetic on / off valves may be provided in the first and second directional pipes 51 and 54, respectively, and these electromagnetic on / off valves may be operated to replace the direction switching valve 50. In addition, when the direction switching valve 50 has a pipeline blocking function, the second electromagnetic switching valve 20 may be omitted.
[0088]
The vehicle air conditioner according to the present invention is not limited to the above-described embodiment, but can of course adopt various configurations without departing from the gist of the present invention.
[0089]
【The invention's effect】
As described above, the vehicle air conditioner according to the present invention can achieve the effect of performing rapid heating by rapidly raising the temperature of the refrigerant during the heating operation at low temperatures.
[Brief description of the drawings]
FIG. 1 is a block diagram of a vehicle air conditioner according to an embodiment.
FIG. 2 is a Mollier diagram showing a thermal cycle of the vehicle air conditioner according to the present embodiment.
FIG. 3 is a block diagram of a vehicle air conditioner according to a first modification of the present embodiment.
FIG. 4 is a block diagram of a vehicle air conditioner according to a second modification of the present embodiment.
FIG. 5 is a graph showing the setting of the throttle opening of the electric expansion valve with respect to the temperature in the vicinity of the second condenser.
[Explanation of symbols]
10, 100, 110 ... Vehicle air conditioner
12 ... Engine 16 ... Compressor
18 ... 1st electromagnetic on-off valve 20 ... 2nd electromagnetic on-off valve
22 ... 1st condenser 30 ... Receiver
32 ... 1st expansion valve 34 ... 2nd expansion valve
36 ... 1st evaporator 38 ... 2nd evaporator
40, 42, 60 ... check valve 46 ... heater
48 ... Auxiliary heater 50 ... Direction switching valve
51 ... First direction pipe 52 ... Second condenser
54 ... Second direction pipe 56 ... Pressure reducing device
70 ... Front seat air conditioning unit 78 ... Rear seat air conditioning unit
86 ... Control unit 102 ... Electric heater

Claims (3)

In a vehicle air conditioner having a first air conditioning unit that air-conditions a first space and a second air conditioning unit that air-conditions a second space,
A compressor that sucks and compresses the refrigerant;
A first electromagnetic on-off valve and a second electromagnetic on-off valve respectively provided in the branched pipe of the discharge port of the compressor;
A first condenser for condensing refrigerant supplied through the first electromagnetic on-off valve;
A second condenser for condensing refrigerant supplied through the second electromagnetic on-off valve;
Provided between the second electromagnetic on-off valve and the second condenser, a refrigerant destination supplied from the second electromagnetic on-off valve is an inlet side pipe line of the second condenser, or the second A direction switching valve for switching to one of the downstream pipes from the outlet side of the condenser;
A first expansion valve and a second expansion valve for expanding the refrigerant condensed only by the first condenser;
A first evaporator for evaporating the refrigerant expanded by the first expansion valve;
A second evaporator for evaporating the refrigerant expanded by the second expansion valve;
A heater for heating air with hot water heated by an engine;
A control unit for overall control;
Have
The first air conditioning unit includes the first expansion valve, the first evaporator, and the heater.
The second air conditioning unit includes the second expansion valve, the second evaporator, and the second condenser,
The control unit switches the direction switching valve so that the refrigerant flows to a pipe line downstream from the outlet side of the second condenser when the outside air temperature is lower than a predetermined temperature, and communicates the second electromagnetic opening / closing valve. The vehicle air conditioner is configured to perform initial heating, and then switch from the initial heating operation to the normal heating operation by switching the direction switching valve so that the refrigerant flows into the conduit on the inlet side of the second condenser. . The vehicle air conditioner according to claim 1,
The vehicle air conditioner further includes an auxiliary heater that heats the refrigerant between the compressor and the second condenser. The vehicle air conditioner according to claim 1 or 2,
The refrigerant is supplied from the compressor to the second condenser,
The vehicular air conditioner is characterized in that the second condenser performs heating by performing heat exchange by condensing a part of the refrigerant in a range in which all the refrigerant is not liquefied.

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