JP3331815B2 - Vehicle air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for a vehicle capable of coping with various operation patterns by combining a heat pump cycle and a hot water circuit, and is suitable as an air conditioner for a bus vehicle. .

[0002]

2. Description of the Related Art Conventionally, in a vehicle air conditioner, when the heater performance decreases until the engine water temperature rises (a period immediately after the engine is started), heating is performed by a heat pump cycle to improve the heating start-up performance. Many proposals have been made. Also, JP-A-6-2629
In Japanese Patent No. 35, the refrigerant gas discharged from the compressor of the air conditioning refrigeration cycle is sent to a heat exchanger for heating the engine cooling water (water-refrigerant heat exchanger), and the heat exchanger heats the engine cooling water. 2. Description of the Related Art There has been proposed an air conditioner for a vehicle in which heater performance is started up at an early stage.

[0003]

However, in the former case, since the temperature of the intake air of the heat exchanger inside the vehicle in the heat pump cycle is low in winter, the temperature of the air blown out of the heat exchanger is also low, resulting in a heating feeling. There is a problem that is bad. On the other hand, in the case of the latter, the amount of heat released from the engine cooling water and the amount of heat released from the refrigerant in the refrigeration cycle can be added to heat the vehicle interior, so that the blown air temperature rises compared to the former. And the heating feeling can be improved.

However, in the latter case, when water is heated by the refrigerant gas discharged from the compressor, a dedicated solenoid valve for switching the refrigerant circuit or the like is provided to send the refrigerant gas discharged from the compressor to the heat exchanger for heating the engine cooling water. It is necessary to newly add a large number of devices to the refrigeration cycle, causing problems such as an increase in product cost and an increase in installation space. In addition, when the engine cooling water is heated, the refrigerant is prevented from flowing through the heat exchangers such as the condenser and the evaporator, which are the original components of the refrigeration cycle. The lubricating oil stays and causes a decrease in the circulating refrigerant flow rate.

[0005] As a result, various problems occur in the operation of the refrigeration cycle, such as insufficient lubrication in the compressor and a reduction in capacity due to a decrease in the flow rate of the circulating refrigerant. The present invention has been made in view of the above points, and provides an air conditioner for a vehicle that uses a heat pump cycle for air conditioning of a vehicle, has an extremely simple configuration, allows the engine water temperature to rise quickly, and can exhibit good heater performance. The purpose is to do.

It is another object of the present invention to provide a vehicle air conditioner which can set a multi-step operation pattern suitable for various air conditioning modes.

[0007]

In order to achieve the above object, the present invention employs the following technical means. According to the first aspect of the present invention, the heater core (2) is provided in the hot water circuit in which the cooling water of the vehicle engine (12) circulates and exchanges heat between the engine cooling water and the blowing air to heat the blowing air.
3) and a heater unit (22) for heating the interior of the vehicle having a blower fan (24) for blowing air to the heater core (23); a compressor (18) driven by the vehicle engine (12); (18) The switching valve (20) for switching the flow direction of the suction and discharge refrigerant, the outdoor heat exchangers (29, 30), the pressure reducing means (33, 46), and the indoor heat exchangers (41, 42) When the heat pump cycle is set to the cooling cycle by the switching valve (20) and the switching valve (20), heat exchange is performed between the refrigerant gas discharged from the compressor (18) and the engine cooling water of the hot water circuit. Water-refrigerant heat exchanger (27)
And the blower fan (2) of the heater unit (22).
4) a control means (52) for controlling the operation of the compressor (18) and the switching valve (20). When the temperature of the engine cooling water is lower than a set temperature in a heating mode, the control means By setting the heat pump cycle to the cooling cycle and operating according to (52), the engine-cooling water is heated by the refrigerant gas discharged from the compressor (18) in the water-refrigerant heat exchanger (27), Air-conditioning for a vehicle in which the operation of the blower fan (24) of the heater unit (22) is stopped and the blower fan (24) of the heater unit (22) is operated after the temperature of the engine cooling water rises above a set temperature. Features the device.

According to the invention of claim 2, in the vehicle air conditioner of claim 1, the indoor heat exchanger of the heat pump cycle is installed upstream of the blast air,
A first heat exchanger (41) located downstream of the pressure reducing means (46) at the time of setting the cooling cycle; and a first heat exchanger (41) installed downstream of the blast air and the pressure reducing means (46) at the time of setting the cooling cycle. And a second heat exchanger (42) located upstream of the refrigerant.

According to a third aspect of the present invention, in the vehicle air conditioner according to the first or second aspect, the water-refrigerant heat exchanger (27) is provided only when the temperature of the engine cooling water is lower than a set temperature. And a temperature response switching means (28) for flowing the engine cooling water from the hot water circuit. In the invention according to claim 4, claim 1 is
In the air conditioner for a vehicle according to any one of (1) to (3), the control means (52) switches a heating capacity by switching a blowing amount of a blowing fan (24) of the heater unit (22) in a heating mode. It is characterized by comprising.

According to a fifth aspect of the present invention, in the vehicle air conditioner according to any one of the first to fourth aspects, the control means (52) includes a blower fan (24) of the heater unit (22). And an operation mode in which the heat pump cycle is set to a heating cycle and operated.

The reference numerals in the parentheses of the above means indicate the correspondence with the concrete means described in the embodiments described later.

[0012]

According to the first to fifth aspects of the present invention,
When the engine water temperature rises immediately after the vehicle engine starts (when the engine water temperature is lower than the set temperature),
By setting the heat pump cycle to the cooling cycle by the control means and operating it, the engine coolant is heated by the refrigerant gas discharged from the compressor in the water-refrigerant heat exchanger, and the operation of the blower fan of the heater unit is stopped, After the temperature of the engine cooling water rises above the set temperature, the blower fan of the heater unit is operated.

Therefore, the initial rise of the engine water temperature is remarkably improved by heating the engine coolant by the refrigerant gas discharged from the compressor at the time of the rise of the engine water temperature and increasing the engine load (increasing the amount of engine waste heat) by driving the compressor. The engine water temperature can be rapidly increased in a short time. And, since the blower fan of the heater unit is operated after the engine water temperature rises above the predetermined temperature, heating is performed by blowing out hot air with high temperature from the beginning without blowing cold air with low temperature into the vehicle interior. And the heating feeling is good.

Further, by setting the heat pump cycle to the cooling cycle, the engine cooling water is heated by absorbing heat from the refrigerant, so that the engine cooling water can be heated using the existing heat pump cycle as it is. Unlike the conventional device, it is not necessary to newly add a large number of dedicated devices such as a solenoid circuit for switching a refrigerant circuit to the refrigeration cycle, thereby suppressing an increase in product cost and an increase in installation space.

In the present invention, the refrigerant flows through the heat exchangers such as the condenser and the evaporator, which are the essential components of the heat pump cycle, so that the refrigerant and the lubricating oil stay in these heat exchangers and the circulating refrigerant. Problems such as a decrease in the flow rate do not occur. In addition to the above, in the invention according to claim 2, as the indoor heat exchanger of the heat pump cycle, the first heat exchanger is installed on the upstream side of the blown air and located on the downstream side of the refrigerant of the pressure reducing means at the time of setting the cooling cycle. A heat exchanger, and a second heat exchanger that is installed on the downstream side of the blast air and that is located on the upstream side of the refrigerant of the pressure reducing means when the cooling cycle is set, so that the first heat exchanger is set when the cooling cycle is set. Even if the heat exchanger cools the blown air, the second heat exchanger can reheat the cooled air, so that the problem of blowing cold air into the vehicle interior can be reduced.

Furthermore, in the invention according to claim 4, the control means is configured to switch the amount of air blown by the blower fan of the heater unit in the heating mode to switch the heating capacity. In the present invention, the control means sets the air flow rate of the blower fan of the heater unit to the maximum, and has an operation mode in which the heat pump cycle is set to the heating cycle and has an operation mode. Suitable multi-stage heating capacity patterns can be set.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 shows a state in which a bus vehicle air conditioner to which the present invention is applied is mounted on a vehicle. FIG. 2 shows a system configuration of a refrigeration cycle (heat pump cycle) and a hot water circuit in the present invention. 1 and 2, reference numeral 10 denotes a vehicle body of a bus vehicle, and reference numeral 11 denotes an engine room disposed under the rearmost floor of the vehicle body 10, in which an engine 12 for driving the vehicle is mounted.

The engine 12 is of a water-cooled type, and its cooling water is cooled by a radiator 13. Reference numeral 14 denotes a thermostat (a temperature responsive valve) which is a well-known thermostat that adjusts the flow of cooling water to the radiator 13 and the bypass circuit 15 in accordance with the temperature of cooling water. Reference numeral 16 denotes an engine-side water pump driven by the engine 12, and 17 denotes a heater water pump, which is an electric water pump driven by a motor.

Reference numeral 18 denotes a compressor for compressing the refrigerant of the refrigeration cycle, which is driven by the engine 12 via an electromagnetic clutch 19. Reference numeral 20 denotes a four-way valve for switching the refrigerant suction / discharge circuit of the compressor 18. The above devices 12 to 20 are installed in the engine room 11. Reference numeral 21 denotes an underfloor space in a substantially central portion of the vehicle body 10.
A heater unit 22 for heating the vehicle interior is installed. The heater unit 22 includes a heater core 23 that heats the heating air by exchanging heat with hot water, a heating fan 24 that blows the heating air to the heater core 23, and a temperature sensor that detects the temperature of the hot water flowing into the heater core 23. (Thermistor) 25 is provided. The heating fan 24 is an electric fan driven by a motor.

Although not shown in FIG. 2, the air outlet side of the heater core 23 is connected to a hot air duct disposed on the floor in the vehicle compartment, and a number of hot air ducts provided on the floor are provided on the floor. Warm air is blown into the passenger compartment from the hot air outlet. 26 is an outdoor unit of the refrigeration cycle, 27 is a water-refrigerant heat exchanger that performs heat exchange between the refrigerant of the refrigeration cycle and hot water, 28 is a thermostat (temperature response valve),
In this example, a mechanical type that switches the hot water circuit by displacing the valve body with a medium having a large volume change due to temperature such as wax is used.

Reference numerals 29 and 30 denote outdoor heat exchangers of the refrigeration cycle, and 31 denotes an outdoor fan for blowing outside air to the outdoor heat exchangers 29 and 30, which is an electric fan driven by a motor. 32 is a receiver for separating gas-liquid refrigerant and storing liquid refrigerant, 33 is a temperature-operated expansion valve for heating, 3
4, 35 and 36 are check valves. The above devices 22 to 36
Is installed in the underfloor space 21. Reference numeral 37 denotes a defroster heater core connected to the downstream side of the hot water of the heating heater core 23. The heater core 37 is installed below the vehicle front window 38 in the vehicle cabin, and heats the blown air to blow out the inside of the front window 38. This is to prevent fogging.

Reference numeral 39 denotes a roof of the vehicle body 10, and reference numeral 40 denotes an indoor unit mounted on the roof 39, which is installed on the indoor heat exchanger 41 of the refrigeration cycle and downstream of the indoor heat exchanger 41 in the air. The heat exchanger 42 for reheating, and the indoor side blower fan 43 which blows inside air (vehicle indoor air) or outside air to both heat exchangers 41 and 42 are provided. The indoor side blower fan 43 is also an electric fan driven by a motor.

Reference numerals 44 and 45 denote solenoid valves, 46 denotes a temperature-operated expansion valve for cooling, and 47 denotes a check valve. The above devices 41 to
47 is installed in the indoor unit 40 on the roof 39. An outside air damper and an inside air damper (not shown) are provided on the air upstream side of the heat exchangers 41 and 42 so that the inside air (vehicle air) or the outside air can be switched and introduced. The downstream sides of the exchangers 41 and 42 are connected to ceiling outlet ducts 48 installed on both left and right sides of the vehicle ceiling shown in FIG. The ceiling outlet duct 48 is provided with a number of air outlets 49.

Reference numeral 50 denotes a drain hose for discharging condensed water generated in the indoor unit 40 on the roof 39 during cooling to the lower side of the vehicle. Reference numeral 51 denotes an air conditioner control panel, which is installed near the driver's seat in the vehicle interior. Operation switches, operation indicator lights, and the like are provided. Next, FIG. 3 is an electric control block diagram, 52 is an air-conditioning control device, 53 is an inside air temperature sensor that detects the temperature inside the vehicle, 54 is an outside air temperature sensor that detects the temperature outside the vehicle, and 55 is a target temperature inside the vehicle. Set the temperature setter,
Reference numeral 56 denotes an air-conditioning operation switch, and 57, a dehumidification switch. These temperature setting device 55, the air-conditioning operation switch 56, and the dehumidification switch 57 are installed on the air-conditioner control panel 51 and are manually operated by an occupant.

The devices 17, 19, 20, 24, 31, 43 whose operation is controlled by the control device 52 are as described above. Next, the operation of the present embodiment in the above configuration will be described. FIG. 4 summarizes the operation of each device for each of the operation patterns A to E in this embodiment. In cooling, the air conditioning operation switch 56 is turned on and the temperature setting device 5 is turned on.
5 is used to set a target temperature. Then, the controller 52 sets the target temperature, the internal air temperature sensor 53, and the external air temperature sensor 54.
The cooling mode is selected by the inside air temperature and the outside air temperature detected by the above, so that the cooling cycle is set by the four-way valve 20 in the refrigeration cycle, and the refrigerant gas discharged from the compressor 18 flows in the direction of arrow A, and the first chamber The liquid refrigerant is condensed in the outer heat exchanger 30, and is subcooled in the second outdoor heat exchanger 29 via the receiver 32.

Then, the liquid refrigerant is depressurized and expanded by the cooling expansion valve 46 through the solenoid valve 45 which is opened, and then the refrigerant exchanges heat with the air blown by the fan 43 in the indoor heat exchanger 41. And evaporate. At this time, the blown air of the fan 43 is cooled by cooling the refrigerant by absorbing the latent heat of vaporization by the refrigerant. This cool air is blown into the vehicle interior through the ceiling outlet duct 48 and the many air outlets 49 to cool the vehicle interior.

The controller 52 compares the inside air temperature and the like detected by the inside air temperature sensor 53 with a target temperature set by the temperature setting device 55, and compares the amount of air blown by the blower fan 43 of the indoor unit 40 (fan speed). By switching between large, medium, and small, and switching the compressor 18 on and off (disconnecting and energizing the electromagnetic clutch 19), temperature control during cooling is automatically performed. The operation at the time of cooling is basically the same as that of the conventional device.

Next, the operation of the heating mode, which is an essential part of the present invention, will be described in detail with reference to the flowchart of FIG. 5. When the air-conditioning operation switch 56 is turned on in winter (step S
1) The heating mode is selected from the target temperature, the outside air temperature, and the like set by the temperature setting device 55 (step S2). Thereby, the heater water pump 17 is started (step S).
3) Then, since the engine cooling water circulates to the heating heater core 23 side, the water temperature is detected by the water temperature sensor 25 provided at the hot water inlet of the heating heater core 23.

Next, at step S4, the water temperature sensor 2
5 is equal to the preset temperature T1 (for example, 4
0 ° C) or more, and when the water temperature is lower than the set temperature T1, the process proceeds to step S5, where the heater start mode B in FIG. 4 is set. In the heater rising mode B, since the water temperature is low, the heating fan 24 is kept stopped, and the engine water temperature is rapidly increased by the operation of the refrigeration cycle.

That is, by turning on the compressor 18 and the four-way valve 20, a cooling cycle in the direction of arrow A is set. Further, since the temperature of the thermostat 28 is lower than the set temperature T3 (for example, 80 ° C.), the flow path to the water-refrigerant heat exchanger 27 is fully opened, and the bypass path 27a is completely closed. The hot water flows into the exchanger 27. Therefore, the refrigerant gas discharged from the compressor 18 is supplied to the water-refrigerant heat exchanger 27.
In this case, heat exchange is performed with the engine cooling water to release heat of condensation into the water, so that the engine cooling water can be preheated. At this time, since the engine 12 drives the compressor 18 via the electromagnetic clutch 19, the load increases by the amount of the compressor drive,
Since the amount of engine waste heat increases, the temperature rise of the engine cooling water can be accelerated.

As described above, the temperature of the engine cooling water can be rapidly raised by absorbing the condensation heat from the refrigeration cycle and increasing the engine load for driving the compressor.
In the refrigeration cycle, the cooling cycle in the direction of arrow A is set as described above.
In order to prevent the refrigerant from radiating heat at 9, 30, the outdoor fan 31 is stopped. On the other hand, indoor unit 4
Since the indoor heat exchangers 41 and 42 need to absorb heat, the blower fan 43 is operated at a low speed (LO).

Therefore, the cool air blows out of the indoor unit 40 during the heating. In this embodiment, the cool air blow can be reduced by the following measures. That is, the blower fan 43 is operated at a low speed (LO) to reduce the air volume, and furthermore, the electromagnetic valve 45 is closed and the electromagnetic valve 44 is opened so that the two indoor heat exchangers 41 and 42 are opened. The cold air that is connected in series on the refrigerant circuit and cooled by the indoor heat exchanger 41 on the upstream side of the air can be reheated by the indoor heat exchanger 42 on the downstream side of the air. That is, since the high-temperature high-pressure refrigerant before the pressure is reduced by the expansion valve 46 flows through the indoor heat exchanger 42 on the downstream side of the air, the cold air can be reheated by the high-pressure refrigerant. As a result, the blowing of cool air from the indoor unit 40 hardly causes a problem.

After the start of the engine 12, time elapses,
If the engine water temperature becomes higher than the set temperature T1 (for example, 40 ° C.), the determination in step S4 becomes YES, and it is determined whether or not the compressor 18 is turned off in step S6. The compressor 18 stops operating (OFF) in step S7.
Is done.

Next, the heating capacity mode is determined in step S8. That is, in this example, any one of the heating capacity modes M5 to M8 is determined from the target temperature, the inside air temperature, the outside air temperature, and the like input to the control device 52. And
When the heating capacity mode of M5 to M7 is selected, the process proceeds to step S9, where it is determined whether or not the compressor 18 is OFF. When the compressor 18 is operating, the compressor is operated in step S10. The operation 18 is stopped (OFF).

Next, in step S11, the heating fan 2
The speed of No. 4 is set corresponding to the heating capacity modes M5 to M7. That is, in the mode of M5, the speed of the heating fan 24 is set to low speed (LO), in the mode of M6, the speed of the heating fan 24 is set to medium speed (Me), and in the mode of M7, the speed of the heating fan 24 is set to medium speed (Me). The speed of the fan 24 is set to high speed (Hi). The fan speed control by the heating capacity mode selection of M5 to M7 is performed in the normal mode C shown in FIG.
It is.

Next, when M8 is selected as the heating capacity mode in step S8, the process proceeds to step S12,
The speed of the heating fan 24 is set to high speed (Hi), and in the refrigeration cycle, a heating cycle (heat pump cycle) in which the refrigerant flows through the four-way valve 20 in the direction of arrow B.
Is set, and the compressor 18 operates. Therefore, the compressor 1
The refrigerant gas 8 discharged from the indoor heat exchanger 41 of the indoor unit 40 on the roof 39 emits condensation heat to the air blown by the blower fan 43 and condenses. The air blown by the blower fan 43 is heated by the condensed heat, becomes hot air, and is blown into the vehicle interior through the ceiling outlet duct 48 and a number of air outlets 49 to heat the vehicle interior.

As described above, in the M8 mode, the heating fan 24 is rotated at a high speed (Hi) in the heater unit 22 to exhibit the maximum heating capacity by the hot water heat source, and the refrigeration cycle is heated by the indoor unit 40 by the heat pump operation. Since the heated warm air can be blown into the vehicle interior, a heating capacity independent of a hot water heat source can be added. Therefore, when driving in congested traffic, when parking, or when the engine 1
Even when the absolute waste heat quantity decreases due to the combustion efficiency of 2,
The heating capacity can be effectively secured by the combination of the above-described heat pump operations, and a decrease in the vehicle interior temperature can be prevented.

Next, the process proceeds to step S13, where it is determined whether or not the water temperature detected by the water temperature sensor 25 is equal to or higher than a preset temperature T2 (for example, 70 ° C.).
If it is lower, the process returns to step S8, and the above operation is repeated. If the water temperature is higher than the set temperature T2, the process proceeds to step S14, and after stopping the compressor 18, the process proceeds to step S8.
Return to

The heating operation in the mode M8 is the mode D when the water temperature is low in FIG. When the manually operated dehumidification switch 57 is turned on, the controller 52 sets the dehumidification mode in FIG. In the dehumidification mode, the blower air is heated by the hot water heat source in the heater unit 22, and the warm air is blown into the vehicle interior. At the same time, in the refrigeration cycle, the cooling cycle is set by the four-way valve 20, the solenoid valve 44 is opened, and the solenoid valve 45 is closed. Therefore, in the indoor unit 40, the solenoid valve 44, the indoor heat exchanger Since the refrigerant flows through the path of the cooling air expansion valve 46 and the indoor heat exchanger 41, the air blown by the blower fan 43 is cooled and dehumidified by the heat exchanger 41 on the upstream side, and then heats up on the upstream side. It is reheated in the exchanger 42.

Therefore, the blast air blown out from the indoor unit 40 into the vehicle interior is dehumidified and has a small temperature drop, so that the dehumidifying operation can be performed satisfactorily.

[Brief description of the drawings]

FIG. 1 is an installation diagram for a bus vehicle according to an embodiment of the present invention.

FIG. 2 is a system diagram showing a configuration of a hot water circuit and a refrigeration cycle in one embodiment of the present invention.

FIG. 3 is a block diagram showing a schematic configuration of electric control according to one embodiment of the present invention.

FIG. 4 is a table summarizing operation modes according to an embodiment of the present invention.

FIG. 5 is a flowchart showing an operation in a heating mode in one embodiment of the present invention.

[Explanation of symbols]

12 ... vehicle engine, 18 ... compressor, 20 ... four-way valve, 2
2 ... heater unit, 23 ... heater core, 24 ... heating fan, 27 ... water-refrigerant heat exchanger, 28 ... thermostat, 29, 30 ... outdoor heat exchanger, 33 ... heating expansion valve, 41, 42 ... An indoor heat exchanger, 46 ... an expansion valve for cooling, 52 ... a control device.

Continuation of front page (56) References JP-A-7-108824 (JP, A) JP-A-6-183249 (JP, A) JP-A-6-143974 (JP, A) JP-A-5-221233 (JP) JP-A-4-78613 (JP, A) JP-A-6-255357 (JP, A) JP-A-6-68919 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB Name) B60H 1/03 B60H 1/22 651

Claims (5)

(57) [Claims] 1. A heater core provided in a hot water circuit in which cooling water of a vehicle engine circulates, for exchanging heat between engine cooling water and blowing air to heat the blowing air, and a blowing fan for blowing the heating core. A compressor unit driven by the vehicle engine, a switching valve for switching a flow direction of suction and discharge refrigerant of the compressor, an outdoor heat exchanger, a decompression unit, and indoor heat A heat pump cycle having an exchanger, and when the heat pump cycle is set to a cooling cycle by the switching valve, refrigerant gas discharged from the compressor;
A water-refrigerant heat exchanger that exchanges heat with the engine cooling water of the hot water circuit; and a control unit that controls the operation of the blower fan, the compressor, and the switching valve of the heater unit. Sometimes, when the temperature of the engine cooling water is lower than a set temperature, the control means sets the heat pump cycle to a cooling cycle to operate, thereby allowing the water-refrigerant heat exchanger to discharge the refrigerant gas from the compressor. While heating the engine cooling water,
An air conditioner for a vehicle, wherein the operation of a blower fan of the heater unit is stopped, and the blower fan of the heater unit is operated after the temperature of the engine cooling water rises to a set temperature or higher. 2. A first heat exchanger which is installed as an indoor heat exchanger of the heat pump cycle on the upstream side of blast air and is located on the downstream side of the refrigerant of the pressure reducing means when the cooling cycle is set. 2. The vehicle air conditioner according to claim 1, further comprising: a second heat exchanger that is installed downstream of the air and that is located upstream of the refrigerant of the pressure reducing unit when the cooling cycle is set. 3. 3. The water-refrigerant heat exchanger further includes a temperature response switching unit that causes the engine cooling water to flow from the hot water circuit only when the temperature of the engine cooling water is lower than a set temperature. The vehicle air conditioner according to claim 1 or 2, wherein 4. The air conditioner according to claim 1, wherein the control unit is configured to switch a heating capacity by switching a blowing amount of a blowing fan of the heater unit in a heating mode. A vehicle air conditioner according to claim 1. 5. The control means is configured to have an operation mode of setting the air flow rate of a blower fan of the heater unit to a maximum and setting the heat pump cycle to a heating cycle for operation. The air conditioner for a vehicle according to any one of claims 1 to 4, wherein: