JP2008006894A - Vehicular air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular air conditioner capable of reducing power consumption of an electric compressor without deteriorating air conditioning feeling when heating. <P>SOLUTION: When an occupant is present, operation is switched to a heat pump cycle for heating the heat medium (water) with a water-refrigerant heat exchanger 24 arranged in a ceiling part of a vehicle to heat the air blowing into a cabin with a heater core 29 using the heat medium as a heat source and arranged in a floor part, and air is blown out toward feet of the occupant to improve the air conditioning feeling. When no occupant is present, operation is switched to a heat pump cycle for directly heating the air blowing into the cabin with a cabin-inside heat exchanger 25 arranged in the ceiling part of the vehicle, and heat transmitting efficiency is improved to reduce power consumption of the electric compressor 21. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle air conditioner that air-conditions a passenger compartment, and is particularly suitable for use in a bus vehicle.

  Conventionally, Patent Document 1 discloses a vehicle air conditioner applied to a bus vehicle that runs on an engine.

  The vehicle air conditioner disclosed in Patent Document 1 includes a refrigeration cycle (heat pump cycle) and an engine cooling water circuit that circulates engine cooling water. The refrigeration cycle has an outdoor side that exchanges heat between outdoor air and refrigerant. A heat exchanger and an indoor heat exchanger that exchanges heat between the air blown out from the passenger compartment and the refrigerant are provided, and the refrigerant flow path is switchable.

  That is, this refrigeration cycle radiates the refrigerant in the outdoor heat exchanger, dissipates the refrigerant in the indoor heat exchanger, and the refrigerant flow path for cooling that causes the refrigerant to absorb heat in the indoor heat exchanger, It is configured to be able to switch between a heating refrigerant flow path that causes the refrigerant to absorb heat in the outdoor heat exchanger. On the other hand, the engine coolant circuit has a heater core that exchanges heat between the engine coolant and the air blown into the passenger compartment.

  And at the time of air_conditionaing | cooling operation which cools a vehicle interior, a refrigerating cycle is switched to the refrigerant | coolant flow path for air_conditioning | cooling, and the cold wind cooled with the indoor side heat exchanger is blown off into a vehicle interior. In addition, this indoor side heat exchanger is arrange | positioned in the air conditioning unit mounted on the vehicle roof, and cold wind blows off toward a passenger | crew upper side from a ceiling part.

  On the other hand, during the normal heating operation for heating the passenger compartment, the compressor operation of the refrigeration cycle is stopped, the engine core coolant is used as a heat source, the passenger compartment air is heated by the heater core, and the heated warm air is supplied to the vehicle. Blow out indoors. In addition, this heater core is arrange | positioned in the heater unit mounted under the vehicle floor, and warm air blows off toward a passenger | crew's leg side from a floor part.

  As described above, cold air is blown out from the ceiling during cooling operation, and warm air is blown out from the floor during normal heating operation, thereby improving the air conditioning feeling of the occupant with the temperature distribution in the passenger compartment as a head-and-foot heat type.

Furthermore, in the air conditioner of Patent Document 1, when the amount of engine waste heat is reduced during heating operation and the air blown into the vehicle interior cannot be sufficiently heated by the heater core, the compressor of the refrigeration cycle is operated and the refrigerant flow for heating By switching to the road, a heat pump cycle is configured, and warm air heated by the indoor heat exchanger is blown out auxiliary from the ceiling to the vehicle interior to ensure heating capacity.
JP-A-8-310227

  By the way, in an electric vehicle (including a fuel cell vehicle) that is not equipped with an engine for driving a vehicle or a hybrid vehicle that stops the engine when the vehicle is stopped, a sufficient amount of heat for heating cannot be obtained from the engine coolant. In addition, a steady driving force for driving the compressor of the refrigeration cycle cannot be obtained from the engine. Therefore, the vehicle air conditioner of Patent Document 1 cannot be applied to an electric vehicle or the like.

  Therefore, a vehicle air conditioner generally applied to an electric vehicle or the like includes a refrigeration cycle that employs an electric compressor and a heat medium circulation circuit that circulates a heat medium (for example, water) serving as a heat source for the heater core. In addition to the outdoor heat exchanger and the indoor heat exchanger, this refrigeration cycle has a heat medium heat exchanger that exchanges heat between the refrigerant and the heat medium.

  Furthermore, this refrigeration cycle dissipates the refrigerant in the outdoor heat exchanger, dissipates the refrigerant in the heat medium heat exchanger, and the cooling medium flow path for cooling that absorbs heat in the refrigerant in the indoor heat exchanger, It is configured to be capable of switching between a heating refrigerant flow path that causes the refrigerant to absorb heat in the outdoor heat exchanger.

  And at the time of air_conditionaing | cooling operation, it switches to the refrigerant | coolant flow path for air_conditioning | cooling, the refrigerating cycle similar to patent document 1 is comprised, and the cool air cooled with the indoor side heat exchanger is directed toward a passenger | crew upper side from a ceiling part. Blow out.

  On the other hand, at the time of heating operation, the refrigerant flow path for heating is switched to constitute a heat pump cycle, the heat medium heated by the heat medium heat exchanger is caused to flow into the heater core, and the heated heat medium is used as a heat source to the heater core. The air blown into the passenger compartment is heated, and the heated warm air is blown out from the floor toward the passenger's feet.

  As a result, similar to Patent Document 1, a head cold foot type vehicle interior temperature distribution is realized, and the air conditioning feeling of the occupant is improved.

  However, when heat is transferred from the refrigerant to the heat medium during the heating operation as described above, and further, heat is transferred from the heat medium to the air blown into the vehicle compartment, the heat medium is directly transferred from the refrigerant to the air blown into the vehicle compartment. The heat transfer efficiency is deteriorated due to the interposition. Therefore, the power consumption of the electric compressor for obtaining desired heating performance increases.

  In order to solve this problem, it is conceivable to directly exchange heat between the refrigerant and the air blown into the passenger compartment during heating operation, and to blow warm air into the passenger compartment, but the indoor heat exchanger is mounted on the vehicle roof. Since it is arrange | positioned in the made air-conditioning unit, a warm air will blow off from a ceiling part and will worsen an air-conditioning feeling.

  In addition, it is conceivable to install a hot air duct that guides the hot air from the roof of the vehicle to the floor and blows it out to the passenger's feet, but the area of the pipe passage that leads the heat medium such as water (liquid) from the roof of the vehicle to the floor On the other hand, since the air passage area of the hot air duct is increased, the space of the passenger compartment is reduced by the installation of the hot air duct, thereby impairing the occupant comfort.

  An object of this invention is to provide the vehicle air conditioner which can reduce the power consumption of an electric compressor, without deteriorating an air-conditioning feeling at the time of heating operation in view of the said point.

  In order to achieve the above object, in the present invention, the electric compressor (21) that compresses and discharges the refrigerant, and the air that is arranged on the ceiling of the vehicle and blows out toward the upper side of the passenger's head. A heat exchanger (25) for exchanging heat between the indoor heat exchanger (25), a heat exchanger (24) for heat exchange between the refrigerant and the heat medium, and a floor portion of the vehicle. A heater core (29) for exchanging heat between the medium and the air blown toward the passenger's feet, an outdoor heat exchanger (20) for exchanging heat between the refrigerant and the outdoor air, and an outdoor heat exchanger (20 ) And the inflow side decompression means (27a) for decompressing and expanding the refrigerant flowing into the vehicle, and in the heating operation for heating the vehicle interior, the indoor side heat exchanger (25) dissipates the refrigerant discharged from the electric compressor (21), Inflow side decompression means (27a) downstream refrigerant in outer heat exchanger (20) The air heating refrigerant flow path for absorbing heat and the heat medium heat exchanger (24) radiate the refrigerant discharged from the electric compressor (21), and the outdoor heat exchanger (20) downstream of the inflow side decompression means (27a). The vehicle air conditioner includes a refrigerant flow path switching unit (26a, 26b) for switching between a heat medium heating refrigerant flow path that causes the refrigerant to absorb heat.

  According to this, the refrigerant flow path switching means (26a, 26b) switches between the air heating refrigerant flow path and the heat medium heating refrigerant flow path, so that the indoor heat exchanger (25) moves toward the head of the passenger. The heat pump cycle that heats the air blown out and the heat pump cycle that heats the heat medium that heats the air blown out toward the feet of the occupant in the heat medium heat exchanger (24) Heating operation can be performed.

  In the heat pump cycle that heats air, heat can be directly transferred from the refrigerant to the air blown into the vehicle interior, so that the heat transfer efficiency can be improved compared to the case where heat is transferred from the refrigerant to the air blown into the vehicle interior via the heat medium. Can be raised. As a result, the power consumption of the electric compressor (21) can be reduced, and the immediate effect at the start of heating operation can be improved.

  Further, in the heat pump cycle that heats the heat medium, the air blown toward the foot of the passenger is heated, so that the air conditioning feeling can be improved by using the cabin temperature distribution as a chill head heat type. Therefore, by appropriately switching between the air heating refrigerant channel and the heat medium heating refrigerant channel during the heating operation, the power consumption of the electric compressor (21) can be reduced without deteriorating the air conditioning feeling when boarding the passenger.

  In addition, the ceiling part in this invention is the meaning containing the site | part located on a passenger | crew's head in vehicles, such as not only the ceiling in a vehicle interior but a roof. Further, the floor means not only on the floor in the passenger compartment, but also includes a portion located in the vicinity of the occupant's feet in the vehicle such as under the floor.

  The vehicle air conditioner having the above characteristics further includes a control means (31) for controlling the operation of the refrigerant flow path switching means (26a, 26b) and a detection means for detecting the presence or absence of a passenger in the vehicle compartment during heating operation. The control means (31) switches to the air heating refrigerant flow path when the detection means detects the absence of an occupant, and further switches to the heat medium heating refrigerant flow path when the detection means detects the presence of an occupant. May be.

  According to this, the efficiency of the heat pump cycle can be improved when the occupant is not present in the passenger compartment, and the air conditioning feeling can be improved when the occupant is present in the passenger compartment. In particular, when the vehicle air conditioner of the present invention is applied to a bus vehicle, the passenger's air conditioning feeling can be improved if the passenger is a passenger excluding the vehicle driver.

  In the vehicle air conditioner having the above characteristics, the control means (31) for controlling the operation of the refrigerant flow path switching means (26a, 26b) and the input means (33c) for the operator to input a refrigerant flow path switching request. The control means (31) may be configured to switch between the air heating refrigerant flow path and the heat medium heating refrigerant flow path in response to the switching request input to the input means (33c).

  According to this, the air heating refrigerant flow path and the heat medium heating refrigerant flow path can be appropriately switched according to the operator's switching request according to the operator's request. The power consumption of the electric compressor (21) can be reduced without deteriorating the air conditioning feeling.

  In the vehicle air conditioner having the above characteristics, the control means (31) for controlling the operation of the refrigerant flow path switching means (26a, 26b) and the elapsed time measuring means for measuring the elapsed time from the start of the heating operation. And the control means (31) switches to the air heating refrigerant channel when the elapsed time is less than a predetermined reference time, and switches to the heat medium heating refrigerant channel when the elapsed time is equal to or longer than the reference time. It may be.

  Further, the vehicle air conditioner that switches the refrigerant flow path according to the elapsed time is provided with a secondary battery (11) that supplies electric power to the vehicle driving motor, and the secondary battery (11) can be charged by an external power source. When applied to a configured vehicle, the reference time may be the time from the start of charging the secondary battery (11) to the completion of charging.

  In general, the occupant is not in the passenger compartment during the time from the start of charging the secondary battery (11) to the completion of charging. Therefore, if the control means (31) switches to the air heating refrigerant flow path and performs preheating (preheating) in the passenger compartment at this time, it is possible to save power in the compressor during preheating. Furthermore, when the occupant gets into the passenger compartment after charging, the control means (31) switches to the heat medium heating refrigerant flow path, so that the air conditioning feeling is not impaired.

  Further, in the vehicle air conditioner having the above-described characteristics, the outlet side decompression means (27b) that decompresses and expands the refrigerant that has flowed out of the outdoor heat exchanger (20), and the refrigerant flow path are switched so that the heating operation and the passenger compartment are performed. A cooling / heating switching means (22) for switching between cooling operation and cooling operation, and the cooling / heating switching means (22) dissipates the refrigerant discharged from the electric compressor (21) in the outdoor heat exchanger (20) during the cooling operation. The indoor side heat exchanger (25) may be switched to a cooling refrigerant flow path that absorbs heat from the downstream side refrigerant in the inflow side decompression means (27a).

  According to this, since the cooling operation is possible and the refrigeration cycle is configured such that the refrigerant is absorbed by the indoor heat exchanger (25) during the cooling operation, the cold air is blown out toward the head of the passenger. Can do. As a result, the air conditioning feeling of the passenger is not impaired even during the cooling operation.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic perspective view for explaining the mounting state of the vehicle air conditioner of the present invention. The vehicle air conditioner of this embodiment is mounted on a bus vehicle 10. The bus vehicle 10 is an electric vehicle that travels by a travel motor (not shown) that is driven by the supply of electric power stored in the battery 11.

  The battery 11 supplies power not only to the driving motor but also to various electric devices for vehicles such as an electric compressor 21 of the air conditioning unit 13 described later, as indicated by a broken line in FIG. In the present embodiment, the battery 11 is divided into two parts and arranged on the ceiling and the floor located at the rearmost part in the vehicle traveling direction A, thereby avoiding the reduction of the vehicle interior space.

  In the present embodiment, a chargeable / dischargeable secondary battery (for example, a nickel metal hydride battery or a lithium ion battery) is adopted as the battery 11 and the charged electric power is supplied to the traveling motor or the like. Alternatively, a fuel cell that generates electricity by electrochemical reaction of hydrogen and oxygen may be employed to supply the generated power.

  An air conditioning unit 13 is disposed above the roof 12 on the front side of the bus vehicle 10, a heater unit 15 is disposed below the floor 14 at the center of the bus vehicle 10, and the air conditioning unit 13 and the heater unit are further disposed. 15 is connected by a hot water pipe 16. The air conditioning unit 13, the heater unit 15, and the hot water pipe 16 constitute the vehicle air conditioner of this embodiment.

  Here, the details of the air conditioning unit 13 and the heater unit 15 will be described with reference to FIG. FIG. 2 is an overall configuration diagram of the vehicle air conditioner according to the present embodiment. First, the air conditioning unit 13 is mainly an integrated (unitized) refrigeration cycle (heat pump cycle), and is roughly divided into an outdoor heat exchanger unit 17, a compressor unit 18, and an indoor heat exchanger unit 19. Is done.

  First, in the air conditioning unit 13, the outdoor heat exchanger unit 17 disposed at the foremost side is provided with an outdoor heat exchanger 20 and an outdoor electric blower (not shown). The outdoor heat exchanger 20 exchanges heat between the refrigerant flowing through the inside and the outdoor air (outside air) blown by the outdoor electric blower.

  Next, the compressor unit 18 is arrange | positioned in the center part among the air-conditioning units 13, and the electric compressor 21, the electric four-way valve 22, the accumulator 23, the water-refrigerant heat exchanger 24, etc. are provided. The electric compressor 21 sucks, compresses and discharges the refrigerant in the refrigeration cycle, and has a fixed capacity type compression mechanism 21a and an electric motor 21b.

  In the present embodiment, a well-known scroll type compression mechanism is employed as the compression mechanism portion 21a. However, other types of compression mechanisms such as a rotary type, a piston type, and a vane type may be employed.

  The electric motor 21b gives a driving force to the compression mechanism unit 21a. The electric motor 21b is supplied with power from the battery 11 via an air conditioning control device 31 to be described later, and the rotation speed is controlled by a control signal from the air conditioning control device 31. . By this rotational speed control, the refrigerant discharge capacity of the electric compressor 21 is adjusted.

  Inside the compressor unit 18, an electric four-way valve 22 is connected to the refrigerant discharge port of the electric compressor 21. The electric four-way valve 22 constitutes a refrigerant flow path switching means for switching the refrigerant flow path, and specifically, cooling that connects between the discharge side of the electric compressor 21 and the outdoor heat exchanger 18 side. The refrigerant flow path for heating and the refrigerant flow path for heating that connects between the discharge port side of the electric compressor 21 and the water-refrigerant heat exchanger 24 side or the indoor heat exchanger 25 side are switched.

  Then, the electric four-way valve 22 switches the refrigerant flow path as described above, thereby switching the refrigerant flow path in the heating operation and cooling operation described later. Therefore, the electric four-way valve 22 is a cooling / heating switching means in the present embodiment. This electric four-way valve 22 is also controlled by an output signal of an air conditioning control device 31 described later.

On the other hand, an accumulator 23 is connected to the refrigerant suction port of the electric compressor 21. The accumulator 23 is a gas-liquid separator that separates the gas-phase refrigerant and the liquid-phase refrigerant and stores the liquid-phase refrigerant.
More specifically, the refrigerant suction port of the electric compressor 21 is connected to the gas-phase refrigerant outlet of the accumulator 23, thereby preventing the liquid-phase refrigerant from returning to the electric compressor 21.

  As described above, the water-refrigerant heat exchanger 24 is connected to one refrigerant inlet / outlet of the electric four-way valve 22. The water-refrigerant heat exchanger 24 constitutes a heat medium heat exchanger that exchanges heat between water as a heat medium and the refrigerant. In addition, you may employ | adopt the fluid which mixed ethylene glycol type antifreeze with water as a heat medium.

  Next, the indoor side heat exchanger unit 19 is arranged at the rearmost among the air conditioning units 13, and includes an indoor side heat exchanger 25, an indoor side electric blower (not shown), on-off valves 26a and 26b, a throttle mechanism 27a, 27b, check valves 28a, 28b and the like are provided.

  The indoor heat exchanger 25 exchanges heat between the refrigerant flowing through the indoor heat exchanger 25 and the air blown into the room by the indoor electric blower. Ceiling outlet ducts (not shown) arranged on the left and right sides of the vehicle ceiling are connected to the downstream side in the air flow direction of the indoor heat exchanger 25, and heat is exchanged by the indoor heat exchanger 25. The air is blown out from the air outlet provided in the ceiling outlet duct toward the upper side of the passenger.

  The indoor heat exchanger 25 is connected so that the refrigerant passage is in parallel with the refrigerant passage of the water-refrigerant heat exchanger 24 described above. Specifically, a branch portion B that branches the refrigerant flow is provided in a refrigerant pipe connecting the electric four-way valve 22 and one refrigerant inlet / outlet of the water-refrigerant heat exchanger 24. And one refrigerant inlet / outlet of the indoor heat exchanger 25 are connected.

  Further, a branch portion C is also provided in the refrigerant pipe connected to the other refrigerant inlet / outlet of the indoor heat exchanger 25, and the other refrigerant inlet / outlet of the water-refrigerant heat exchanger 24 is connected to the branch portion C. Has been. An opening / closing valve 26a for opening and closing the refrigerant pipe is provided between the branching section B and the indoor side heat exchanger 25, and an opening / closing valve 26b is also provided between the branching section C and the water-refrigerant heat exchanger 24. ing.

  These on-off valves 26a and 26b are electromagnetic valves that are opened and closed by a control voltage of the air-conditioning control device 31, and the air-conditioning control device 31 opens and closes the on-off valves 26a and 26b, whereby the refrigerant discharged from the electric compressor 21 is heated indoors. The air heating refrigerant flow path leading to the exchanger 25 and the heat medium heating refrigerant flow path leading to the water-refrigerant heat exchanger 24 are switched. Therefore, the on-off valves 26a and 26b are refrigerant flow path switching means in the present embodiment.

  Furthermore, the branch part C is connected to the outdoor heat exchanger 20 of the outdoor heat exchanger unit 17 described above, and 2 arranged between the branch part C and the outdoor heat exchanger 20 in parallel. Two refrigerant flow paths are provided. In one refrigerant flow path, a check valve 28a and a throttle mechanism 27a that allow only the refrigerant flow from the branch portion C side to the outdoor heat exchanger 20 side are arranged.

  This throttle mechanism 27a expands the refrigerant flowing into the outdoor heat exchanger 20 under reduced pressure, and constitutes the inflow side pressure reducing means of this embodiment. Further, in the present embodiment, specifically, as the throttle mechanism 27a, a known mechanical expansion valve that adjusts the opening degree of the valve mechanism so that the refrigerant pressure passing through the branch portion C becomes a target high pressure is adopted. .

  In the other refrigerant flow path, a check valve 28b that allows only the refrigerant flow from the outdoor heat exchanger 20 side to the branching section C side and a throttle mechanism 27b similar to the throttle mechanism 27a are arranged. . The throttle mechanism 27b constitutes outflow side decompression means for decompressing and expanding the refrigerant flowing out of the outdoor heat exchanger 20. Furthermore, the throttle mechanism 27b adjusts the opening degree of the valve mechanism so that the pressure of the refrigerant flowing out of the outdoor heat exchanger 20 becomes a target high pressure.

  Next, details of the heater unit 15 will be described. The heater unit 15 is provided with a heater core 29 and a hot air electric blower (not shown). The heater core 29 exchanges heat between the heat medium flowing through the heater core 29 and the air blown into the room by the hot air electric blower.

  On the downstream side of the heater core 29 in the air flow direction, floor outlet ducts (not shown) disposed on the left and right sides of the upper part of the vehicle floor are connected, and the air (hot air) heat exchanged by the heater core 29 is on the floor. It blows out toward the passenger | crew's leg | foot side from the air blower outlet provided in the blowing duct.

  The hot water pipe 16 connecting the air conditioning unit 13 and the heater unit 15 is housed inside the bus vehicle wall, and includes the water-refrigerant heat exchanger 24 in the air conditioning unit 13 and the heater core 29 in the heater unit 15. Connected. Further, a water pump 30 for circulating the heat medium is connected to the hot water pipe 16.

  When the water pump 30 operates, the heat medium (water) circulates through the water-refrigerant heat exchanger 24 and the heater core 29. The water pump 30 is also activated by a control signal from the air conditioning controller 31.

  Next, the outline of the electric control unit according to the present embodiment will be described with reference to FIG. 3. The air conditioning control device 31 includes a known microcomputer including a CPU, a ROM, a RAM, and the like and peripheral circuits thereof. The air conditioning control device 31 performs various calculations and processes based on the control program stored in the ROM, and controls the operations of the various electric devices 21, 22, 26a, 26b, 30 and the like described above.

  A detection signal from the sensor group 32 and various operation signals from the operation panel 33 are input to the air conditioning control device 31. Specifically, an outside air sensor or the like that detects an outside air temperature (a temperature outside the passenger compartment) is provided as the sensor group 32.

  The operation panel 33 includes an operation switch 33a for operating the vehicle air conditioner, a cooling / heating switch 33b for switching between the cooling operation and the heating operation, and a heating mode switching switch for switching between the air heating operation and the heat medium heating operation during the heating operation. 33c, a temperature setting switch 33d for setting a target temperature in the passenger compartment that is an air-conditioning target space, and the like are provided.

  Next, the operation of the present embodiment in the above configuration will be described. First, the cooling operation for cooling the passenger compartment will be described with reference to FIG. FIG. 4 is an enlarged configuration diagram of the air conditioning unit 13 side in the overall configuration diagram of FIG. 2, and the refrigerant flow direction during the cooling operation is indicated by solid line arrows.

  The cooling operation is started when the air conditioning switching switch 33b is switched to the cooling operation side in a state where the operation switch 33a is turned on. First, when the operation switch 33 a is turned on, the air conditioning control device 31 supplies electric power to the electric motor 21 b of the electric compressor 21 to operate the electric compressor 21.

  Further, when the air conditioning switching switch 33b is switched to the cooling operation side, the air conditioning control device 31 connects the electric four-way valve 22 between the discharge port side of the electric compressor 21 and the outdoor heat exchanger 18 side. Switching to the refrigerant flow path, opening the on-off valve 26a, closing the on-off valve 26b, and stopping the operation of the water pump 30.

  Therefore, during the cooling operation, the refrigerant discharged from the electric compressor 21 flows into the outdoor heat exchanger 20 through the electric four-way valve 22 as indicated by solid line arrows in FIG. The refrigerant flowing into the outdoor heat exchanger 20 exchanges heat with the outdoor air blown by the outdoor electric blower to radiate heat.

  In the present embodiment, a normal chlorofluorocarbon refrigerant is used as the refrigerant, and a subcritical cycle in which the high-pressure side pressure of the refrigeration cycle does not exceed the critical pressure of the refrigerant is configured. Therefore, during the cooling operation, the outdoor heat exchanger 20 exerts an effect as a condenser that radiates and condenses the refrigerant discharged from the electric compressor 21.

  The refrigerant that has flowed out of the outdoor heat exchanger 20 flows into the throttle mechanism 27b by the function of the check valve 28a, and is decompressed and expanded in the throttle mechanism 27b. Furthermore, since the on-off valve 26a is closed during the cooling operation, the refrigerant on the downstream side of the throttle mechanism 27b flows into the indoor heat exchanger 25.

  The refrigerant flowing into the indoor heat exchanger 25 absorbs heat from the air blown into the room by the indoor electric blower and evaporates. Accordingly, during the cooling operation, the indoor heat exchanger 25 exerts an action of absorbing heat to the refrigerant on the downstream side of the throttle mechanism 27b which is the outflow side pressure reducing means. The blown air (cold air) cooled by the indoor heat exchanger 25 is blown out toward the passenger's upper head via the ceiling blowing duct as described above.

  The refrigerant that has flowed out of the indoor heat exchanger 25 flows into the accumulator 23 through the electric four-way valve 22, and the gas-phase refrigerant of the refrigerant that has been gas-liquid separated by the accumulator 23 is sucked into the electric compressor 21 again. Is done. Therefore, during the cooling operation, the well-known refrigeration in which the refrigerant is circulated in the order of the electric compressor 21 (compression) → the outdoor heat exchanger 20 (condensation) → the throttle mechanism 27b (expansion) → the indoor heat exchanger 25 (evaporation). A cycle is constructed.

  Further, since the cool air is blown out toward the passenger's upper head during the cooling operation, the passenger's air conditioning feeling can be improved by realizing a head cold foot type vehicle interior temperature distribution.

  Next, of the heating operation for heating the passenger compartment, the heat medium heating operation will be described with reference to FIG. FIG. 5 is an enlarged configuration diagram of the air conditioning unit 13 side in the overall configuration diagram of FIG. 2, and the refrigerant flow direction during the heat medium heating operation is indicated by a solid line arrow.

  The heat medium heating operation is started when the air conditioning switching switch 33b is switched to the heating operation side and the heating mode switching switch 33c is switched to the heat medium heating operation side with the operation switch 33a being turned on.

  During this heat medium heating operation, the air conditioning control device 31 switches the electric four-way valve 22 to the heating refrigerant flow path that connects the discharge side of the electric compressor 21 and the water-refrigerant heat exchanger 24 side. Further, the on-off valve 26a is closed and the on-off valve 26b is opened to switch to the heat medium heating refrigerant flow path, and the water pump 30 is operated.

  Therefore, during the heat medium heating operation, the refrigerant discharged from the electric compressor 21 has the open / close valve 26a in the closed state and the open / close valve 26b in the open state, so the solid arrow D in FIG. As shown in FIG. 5, the refrigerant flows into the water-refrigerant heat exchanger 24 via the electric four-way valve 22 and the branch portion B.

  The refrigerant flowing into the water-refrigerant heat exchanger 24 exchanges heat with the heat medium (water) circulating through the water-refrigerant heat exchanger 24 and the heater core 29 by the water pump 30 to dissipate heat. That is, during the heat medium heating operation, the water-refrigerant heat exchanger 24 exerts an action of radiating heat from the refrigerant discharged from the electric compressor 21, while the water-refrigerant heat exchanger 24 heats the heat medium (water). Demonstrate the effect.

  In addition, the flow direction of the heat medium (water) in the water-refrigerant heat exchanger 24 is a flow direction opposite to the refrigerant flow direction, whereby the heat exchange performance of the water-refrigerant heat exchanger 24 is achieved. Has improved.

  The refrigerant flowing out of the water-refrigerant heat exchanger 24 passes through the branch part C, flows into the throttle mechanism 27a side by the function of the check valve 28b, is decompressed and expanded in the throttle mechanism 27a, and is subjected to outdoor heat exchange. Flow into the vessel 20.

  The refrigerant flowing into the outdoor heat exchanger 20 absorbs heat from the outdoor air blown by the outdoor electric blower and evaporates. Therefore, during the heat medium heating operation, the outdoor heat exchanger 20 exerts an action of absorbing heat to the refrigerant on the downstream side of the throttle mechanism 27b that is the inflow side pressure reducing means.

  The refrigerant that has flowed out of the outdoor heat exchanger 20 flows into the accumulator 23 via the electric four-way valve 22, and the gas-phase refrigerant of the refrigerant that has been gas-liquid separated by the accumulator 23 is sucked into the electric compressor 21 again. Is done. Accordingly, during the heat medium heating operation, the refrigerant is circulated in the order of the electric compressor 21 (compression) → the water-refrigerant heat exchanger 24 (condensation) → the throttle mechanism 27a (expansion) → the outdoor heat exchanger 20 (evaporation). A known refrigeration cycle (heat pump cycle) is constructed.

  On the other hand, the heat medium (water) heated by the water-refrigerant heat exchanger 24 flows into the heater core 29 via the hot water pipe 16. The heat medium (water) flowing into the heater core 29 exchanges heat with the air blown into the room by the hot air electric blower, and the air heated by the heater core 29 (warm air) is on the floor as described above. The air is blown out toward the occupant's feet through the blowout duct.

  As described above, during the heat medium heating operation, the warm air is blown out toward the passenger's feet, so that the temperature distribution in the passenger compartment can be realized and the air conditioning feeling of the passenger can be improved.

  Next, an air heating operation will be described among the heating operations for heating the passenger compartment. The broken line arrows shown in FIG. 5 indicate the refrigerant flow direction during the air heating operation. The air heating operation starts when the cooling / heating changeover switch 33b is switched to the heating operation side and the heating mode changeover switch 33c is switched to the air heating operation side with the operation switch 33a being turned on.

  At the time of this air heating operation, the air conditioning control device 31 switches the electric four-way valve 22 to the heating refrigerant flow path connecting the discharge side of the electric compressor 21 and the water-refrigerant heat exchanger 24 side. Further, the on-off valve 26a is opened and the on-off valve 26b is closed to switch to the air heating refrigerant flow path.

  Therefore, during the air heating operation, the refrigerant discharged from the electric compressor 21 has the open / close valve 26a opened and the open / close valve 26b closed, so that the broken line arrow E in FIG. As shown, the air flows into the indoor heat exchanger 25 via the electric four-way valve 22, the branch B and the on-off valve 26a.

  The refrigerant that has flowed into the indoor heat exchanger 25 dissipates heat to the air blown into the room by the indoor electric blower and condenses. Therefore, during the air heating operation, the indoor heat exchanger 25 acts as a radiator that radiates the refrigerant discharged from the electric compressor 21. And the blowing air (warm air) heated in the indoor side heat exchanger 25 is blown out toward the passenger | crew upper side via a ceiling blowing duct.

  The refrigerant that has flowed out of the indoor heat exchanger 25 flows in the order of the throttle mechanism 27a → the outdoor heat exchanger 20 → the electric four-way valve 22 → the accumulator 23 in the same manner as in the heat medium heating operation, and again in the electric compressor 21. Inhaled. Therefore, during the air heating operation, the refrigerant is circulated in the order of the electric compressor 21 (compression) → the indoor heat exchanger 25 (condensation) → the throttle mechanism 27a (expansion) → the outdoor heat exchanger 20 (evaporation). It constitutes a refrigeration cycle (heat pump cycle).

  As described above, since heat can be directly transferred from the refrigerant to the air blown into the vehicle interior during the air heating operation, the heat transfer efficiency is increased compared to the case where heat is transferred from the refrigerant to the air blown into the vehicle interior via the heat medium. Can be made. As a result, the power consumption of the electric compressor 21 can be reduced, and the immediate effect at the start of heating operation can be improved.

  Further, in the present embodiment, during heating operation, the on-off valves 26a and 26b constituting the refrigerant flow switching means perform air heating operation (air heating refrigerant flow channel) and heat medium heating operation (heat medium heating refrigerant flow channel). Since it can be switched, the power consumption of the electric compressor 21 can be reduced without deteriorating the air conditioning feeling of the occupant by appropriately switching between the air heating operation and the heat medium heating operation.

  Further, as in this embodiment, a heating mode change-over switch 33c that constitutes an input means for an operator to input a refrigerant flow switching request is provided, and air heating operation and heat medium heating are performed according to the operator's request. If the operation can be switched as appropriate, the power consumption of the electric compressor 21 can be reduced more appropriately without deteriorating the air-conditioning feeling when boarding the passenger.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be variously modified as follows.

  (1) In the above-described embodiment, an example in which the vehicle air conditioner of the present invention is applied to an electric vehicle (including a fuel cell vehicle) has been described. However, two traveling powers, that is, an engine that is an internal combustion engine and a traveling motor. You may apply to the hybrid vehicle which has a source.

  In the above-described embodiment, the vehicle air conditioner of the present invention is applied to a bus vehicle. However, the indoor heat exchanger 25 and the water-refrigerant heat exchanger 24 are disposed on the vehicle ceiling, and the heater core 29 is provided. As long as the vehicle is arranged on the vehicle floor, the vehicle is not limited to a bus vehicle, and may be applied to a wagon car, a minivan, or the like.

  (2) In the above-described embodiment, the heat medium heated by the water-refrigerant heat exchanger 24 is used as the heat source of the heater core 29 during the heating operation. However, in an electric vehicle, cooling for battery cooling is performed. Water may be used as an auxiliary heat source. Further, in the hybrid vehicle, engine cooling water may be used as an auxiliary heat source.

  Specifically, the cooling water circuit is provided so that the cooling water for cooling the battery and the cooling water for engine cooling flow into the heater core 29 in parallel with the heat medium heated by the water-refrigerant heat exchanger 24. The cooling water may be allowed to flow into the heater core 29 only when the heat quantity for heating can be obtained from the cooling water.

  (3) In the above-described embodiment, the air heating operation (air heating refrigerant flow path) and the heat medium heating operation (heat medium heating refrigerant flow path) according to the switching request of the operating vehicle by the heating mode changeover switch 33c that is the input means. However, the switching between the air heating operation and the heat medium heating operation is not limited to this.

  For example, a detection means for detecting the presence or absence of a passenger in the passenger compartment during heating operation is provided. When the detection means detects no occupant, the air conditioning control means 31 switches to the air heating operation, and the detection means detects the presence of an occupant. When it does, you may make it switch to a heat-medium heating operation.

  Thereby, when a passenger | crew does not exist in a vehicle interior, the efficiency of a heat pump cycle can be improved, and when a passenger | crew exists in a vehicle interior, air-conditioning feeling can be improved. As the detection means, for example, a weight sensor that detects the presence or absence of an occupant by a change in the weight of the passenger compartment, a seating sensor that determines whether or not an occupant is seated on a seat in the passenger compartment, and within a predetermined range It is possible to employ an infrared sensor or the like that detects the presence or absence of other personnel.

  In addition to this, for example, an elapsed time measuring unit that measures an elapsed time from the start of the heating operation is provided, and the air conditioning control unit 31 performs air heating when the elapsed time is less than a predetermined reference time. When the elapsed time is equal to or longer than a predetermined time, the operation may be switched to the heat medium heating operation. As the elapsed time measuring means, timer means built in the air conditioning control means 31 can be used.

  Furthermore, in the bus vehicle having the same configuration as that of the above-described embodiment, the reference time may be a time from when charging of the secondary battery is started to when charging is completed.

  Since the passengers are generally not on board while the secondary battery is being charged, switching to air heating operation and preheating (preheating) in the passenger compartment can save power in the compressor during preheating. Can do. Further, after charging, when the occupant gets into the passenger compartment, the air conditioning feeling is not impaired as long as the occupant switches to the heat medium heating operation.

  (4) In the embodiment described above, in the heat medium heating operation, the refrigerant is radiated by the water-refrigerant heat exchanger 24, and in the air heating operation, the refrigerant is radiated by the indoor heat exchanger 25. When it is desired to warm the passenger compartment rapidly, the water-refrigerant heat exchanger 24 and the indoor heat exchanger 25 may simultaneously radiate the refrigerant.

  Specifically, the on-off valves 26a and 26b may be opened at the same time during the heating operation, and the refrigerant may be radiated by both the heat exchangers 24 and 25. At this time, if the refrigerant heat radiation amount in the indoor heat exchanger 24 is reduced with respect to the refrigerant heat radiation amount in the water-refrigerant heat exchanger 24, deterioration of the air conditioning feeling can be suppressed.

It is a general-purpose perspective view explaining the mounting state to the bus vehicle of the vehicle air conditioner of one Embodiment. 1 is an overall configuration diagram of a vehicle air conditioner according to an embodiment. It is a block diagram of the electric control part of one Embodiment. It is explanatory drawing explaining the refrigerant | coolant flow of the air conditioning unit at the time of the air_conditionaing | cooling operation of one Embodiment. It is explanatory drawing explaining the refrigerant | coolant flow of the air conditioning unit at the time of heating operation of one Embodiment.

Explanation of symbols

21 ... Electric compressor, 20 ... Outdoor heat exchanger, 22 ... Electric four-way valve,
24 ... Water-refrigerant heat exchanger, 25 ... Indoor heat exchanger, 29 ... Heater core,
26a, 26b ... open / close valve, 27a, 27b ... throttling mechanism, 31 ... air conditioning control means,
33c ... Heating mode selector switch.

Claims (6)

An electric compressor (21) for compressing and discharging the refrigerant;
An indoor heat exchanger (25) disposed on the ceiling of the vehicle for exchanging heat between the refrigerant and the air blown toward the passenger's upper head;
A heat medium heat exchanger (24) disposed on the ceiling portion for exchanging heat between the refrigerant and the heat medium;
A heater core (29) disposed on the floor of the vehicle for exchanging heat between the heat medium and air blown toward the foot of the passenger;
An outdoor heat exchanger (20) for exchanging heat between the refrigerant and the outdoor air;
Inflow side decompression means (27a) for decompressing and expanding the refrigerant flowing into the outdoor heat exchanger (20);
During the heating operation for heating the passenger compartment, the refrigerant discharged from the electric compressor (21) is radiated by the indoor heat exchanger (25), and the inflow side decompression means (20) is discharged by the outdoor heat exchanger (20). 27a) An air heating refrigerant flow path that absorbs heat from the downstream refrigerant, and the heat medium heat exchanger (24) radiates the refrigerant discharged from the electric compressor (21), and the outdoor heat exchanger (20) A vehicle air conditioner comprising: refrigerant flow switching means (26a, 26b) for switching the inflow side decompression means (27a) to a heat medium heating refrigerant flow path that absorbs heat from a downstream refrigerant. Control means (31) for controlling the operation of the refrigerant flow path switching means (26a, 26b);
Detecting means for detecting the presence or absence of a passenger in the passenger compartment during the heating operation,
The control means (31) switches to the air heating refrigerant flow path when the detection means detects no occupant, and further switches to the heat medium heating refrigerant flow path when the detection means detects presence of an occupant. The vehicle air conditioner according to claim 1, wherein the vehicle air conditioner is configured as described above. Control means (31) for controlling the operation of the refrigerant flow path switching means (26a, 26b);
An input means (33c) for an operator to input a switching request for the refrigerant flow path;
The control means (31) is configured to switch between the air heating refrigerant flow path and the heat medium heating refrigerant flow path in response to a switching request input to the input means (33c). The vehicle air conditioner according to claim 1. Control means (31) for controlling the operation of the refrigerant flow path switching means (26a, 26b);
Elapsed time measuring means for measuring the elapsed time from the start of the heating operation,
The control means (31) switches to the air heating refrigerant channel when the elapsed time is less than a predetermined reference time, and switches to the heat medium heating refrigerant channel when the elapsed time is equal to or more than the reference time. The vehicle air conditioner according to claim 1, wherein the vehicle air conditioner is configured as described above. The vehicle air conditioner according to claim 4, further comprising a secondary battery (11) for supplying electric power to a vehicle driving motor, wherein the secondary battery (11) is applied to a vehicle configured to be rechargeable by an external power source. Because
The vehicle air conditioner characterized in that the reference time is a time from the start of charging the secondary battery (11) to the completion of charging. Outflow side decompression means (27b) for decompressing and expanding the refrigerant that has flowed out of the outdoor heat exchanger (20);
Air-conditioning switching means (22) for switching the refrigerant flow path to switch between the heating operation and the cooling operation for cooling the passenger compartment,
The air conditioning switching means (22) radiates the refrigerant discharged from the electric compressor (21) by the outdoor heat exchanger (20) during the cooling operation, and the indoor heat exchanger (25) The vehicular air conditioner according to any one of claims 1 to 5, wherein the outflow side decompression means (27b) is switched to a cooling refrigerant flow path that absorbs heat from the downstream side refrigerant.

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