JP2003175719A - Vehicular air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure a window glass fogging preventive effect in a hot gas heating mode, and, simultaneously, to exhibit effective heating performance in the hot gas heating mode. <P>SOLUTION: This vehicular air conditioner is structured to switch a refrigerating cycle for cooling actuating an interior heat exchanger as an evaporator, and a hot gas heater cycle actuating the interior heat exchanger as a radiator. The presence or absence of water-retaining amount in the interior heat exchanger is determined in a heating mode by the hot gas heater cycle (S20). A compressor is intermittently controlled to make the blowing air temperature of the interior heat exchanger not less than a fogging preventive target temperature, when the presence of the water-retaining amount is determined (S40, S30, S50). The fogging preventive temperature is made to a window glass temperature at high vehicular speed, and corrected to a higher temperature side than at the time of high vehicular speed, at low vehicular speed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention introduces a compressor discharge gas refrigerant (hot gas) directly into an indoor heat exchanger (evaporator) in a heating mode, so that the indoor heat exchanger serves as a gas refrigerant radiator. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle air conditioner that exhibits a hot gas heating function, and more particularly to a system that prevents condensed glass from evaporating in a room heat exchanger to cloud a window glass in a heating mode.

[0002]

2. Description of the Related Art Conventionally, in a vehicle air conditioner, hot water (engine cooling water) is circulated in a heating heat exchanger during heating in winter,
In this heating heat exchanger, hot water is used as a heat source to heat the conditioned air. In this case, when the temperature of the hot water is low, the temperature of the air blown into the vehicle interior may decrease and the required heating capacity may not be obtained.

Therefore, Japanese Patent Application Laid-Open No. 5-272817 proposes a vehicle air conditioner capable of exhibiting a heating function by a hot gas heater cycle. In this conventional device, when the hot water temperature is lower than a predetermined temperature such as when the engine is started, the compressor discharge gas refrigerant (hot gas)
Is introduced into the evaporator by bypassing the condenser, and the evaporator dissipates heat from the gas refrigerant to the conditioned air, so that the auxiliary heating function can be exerted. That is, in the above conventional apparatus, the evaporator, which is one indoor heat exchanger installed in the air conditioning case, is switched and used as the cooler in the cooling mode and the radiator in the heating mode.

Meanwhile, in a vehicle air conditioner, an inside air mode may be set to prevent introduction of contaminated outside air during heating in winter. In this case, it is necessary to exert the cooling and dehumidifying action of the evaporator in order to prevent the window glass from becoming frosted, so the refrigeration cycle should be used in the cooling mode until the outside air temperature drops to around 0 ° C. is there.

Therefore, when the outside temperature is around 0 ° C., the refrigeration cycle is operated in the cooling mode to prevent the window glass from being fogged, and then the refrigeration cycle is changed to the hot gas heater cycle (heating mode) to improve the heating capacity. ) Occurs when switching to. In addition, after the previous cooling mode operation of the refrigeration cycle, the refrigeration cycle may be temporarily stopped, and thereafter the refrigeration cycle may be started in the hot gas heater cycle (heating mode).

[0006]

In the above case, since the condensed water generated in the cooling mode of the refrigeration cycle remains on the surface of the indoor heat exchanger, when the refrigeration cycle is started in the heating mode, The indoor heat exchanger acts as a radiator of the refrigerant gas, and the temperature of the indoor heat exchanger rapidly rises.
Therefore, the condensed water on the surface of the indoor heat exchanger evaporates, high-humidity air blows out into the vehicle compartment, and the vehicle window glass becomes cloudy.

Further, since the condensed water once generated in the indoor heat exchanger due to the operation in the cooling mode is hard to evaporate in the low outside temperature in winter and may remain for a long time, immediately after the switching from the cooling mode to the heating mode. Even if it is not, activation of the heating mode of the refrigeration cycle may cause fogging of the vehicle window glass.

Therefore, the inventors of the present invention first disclosed in Japanese Patent Laid-Open No.
No. 219034 discloses a vehicle air conditioner that exhibits a hot gas heating function, and proposes an invention aimed at preventing condensation of water on a window glass from evaporating condensed water in an indoor heat exchanger in a heating mode. There is.

In this prior art, a physical quantity related to the temperature of the window glass and the indoor air humidity in the vicinity of the window glass is detected, and it is determined whether or not the window glass is fogged based on this physical quantity to determine whether or not the window glass is fogged. When it is determined that, the refrigeration cycle is controlled so as to suppress the temperature of the indoor heat exchanger, specifically, the temperature of the air blown out of the indoor heat exchanger, and the condensed water in the indoor heat exchanger is thereby controlled. It suppresses the evaporation of water and prevents the fogging of the window glass.

However, when the above-mentioned prior art is experimentally examined concretely, whether or not the window glass is fogged is indirectly determined based on the physical quantity related to the temperature of the window glass and the indoor air humidity near the window glass. Since it is a method of determining (estimating), there is a case where the temperature control is deviated from the actual state of the amount of condensed water held in the indoor heat exchanger (referred to as water holding amount in this specification).

That is, in the above-mentioned prior art, since the amount of water retained in the indoor heat exchanger is not directly determined, when condensed water is not retained in the indoor heat exchanger, that is, there is no actual amount of retained water. Even if the control for preventing the fogging of the window glass is unnecessary, the temperature of the air blown out from the indoor heat exchanger may be suppressed to unnecessarily limit the heating capacity in the hot gas heating mode.

The present invention has been made in view of the above points,
While ensuring the anti-fog effect on the vehicle window glass in the hot gas heating mode, at the same time accurately determining whether or not the anti-fog control for the window glass is necessary so that the heating capacity in the hot gas heating mode can be effectively exhibited. The purpose is to

Another object of the present invention is to switch the fogging prevention effect of the vehicle window glass and the priority of the heating capacity exertion in the hot gas heating mode in accordance with the change in the vehicle speed.

[0014]

In order to achieve the above object, in the invention described in claim 1, the refrigerant discharged from the compressor (10) is supplied to the outdoor heat exchanger (14) and the cooling decompressor ( 16) and the indoor heat exchanger (18) to return to the compressor (10), and thereby the refrigeration cycle (C) for cooling, which operates the indoor heat exchanger (18) as an evaporator, and discharge from the compressor (10). The separated refrigerant is transferred to the outdoor heat exchanger (14).
By bypassing and returning to the compressor (10) through the indoor heat exchanger (18), the hot gas heater cycle (H) that operates the indoor heat exchanger (18) as a radiator can be switched, The indoor heat exchanger (18) is arranged in an air-conditioning case (22) in which air flows toward the vehicle interior, and the indoor heat exchanger (1) is operated by the cooling refrigeration cycle (C).
The cooling mode is executed by blowing the air cooled in 8) into the passenger compartment, and the heating mode is performed by blowing the air heated in the indoor heat exchanger (18) into the passenger compartment by the hot gas heater cycle (H). And the determination means (S20) for determining the presence / absence of a water retention amount in the indoor heat exchanger (18), and the determination means (S20) for the water retention amount in the heating mode. When judged, as a target temperature of the air blown out from the indoor heat exchanger (18), a fog stopper that prevents the air blown out from the air conditioning case (22) from reaching the dew point even if cooled by the vehicle window glass Control means (S40, S30, S) that sets a target temperature and controls the temperature of the air blown from the indoor heat exchanger (18) to be equal to or lower than the fog-prevention target temperature.
50), and the target temperature for preventing fog is corrected to a higher temperature side at low vehicle speed than at high vehicle speed.

According to this, when it is determined that there is a water retention amount in the heating mode, the indoor heat exchanger (18) is placed within a range in which the air blown out from the air conditioning case (22) does not reach the dew point even if it is cooled by the vehicle window glass. ), The effect of preventing fogging of the vehicle window glass in the hot gas heating mode can be exerted.

Moreover, the presence / absence of a water retention amount in the indoor heat exchanger (18) is directly determined, and when it is determined that there is a water retention amount in the heating mode, the temperature of air blown out from the indoor heat exchanger (18) is suppressed. When the indoor heat exchanger (18) is controlled so that there is no water retention amount, the suppression control of the blown air temperature of the indoor heat exchanger (18) is not performed. As a result, the temperature of the air blown from the indoor heat exchanger (18) is not suppressed even when the antifogging control is not required, and the heating capacity in the hot gas heating mode can be effectively exhibited.

Further, the following effects can be obtained by correcting the anti-fog target temperature at a low vehicle speed to a temperature higher than that at a high vehicle speed.

That is, since the driver has more driving operation at low vehicle speed than at high vehicle speed, even if the window glass of the vehicle is partially fogged, defrosting operation of the window glass, for example, There is enough time to clear the window glass by performing operations such as switching the blowout mode to the defroster mode.

On the contrary, when the vehicle speed is high, the driver cannot afford to drive, and even if the window glass of the vehicle is partially fogged, there is a possibility that the driver's field of vision is narrowed to cause a danger. Therefore, it is necessary to surely prevent the window glass from being fogged at high vehicle speeds. That is, at high vehicle speeds, it is better to give priority to the anti-fog on the window glass, and at low vehicle speeds, it is better to give priority to improving the heating performance rather than anti-fog on the window glass.

In view of the above point, in view of the above point, the fog-preventing target temperature is corrected to a higher temperature side at a low vehicle speed than at a high vehicle speed, so that the temperature of the air blown out from the indoor heat exchanger (18) is increased to make it hot. The gas heating capacity can be improved. Contrary to this,
When the vehicle speed is high, the temperature of the air blown out from the indoor heat exchanger (18) is controlled to a target temperature for preventing fog which is lower than when the vehicle speed is low, so that the window glass can be more reliably prevented from fog. It can contribute to securing visibility.

According to a second aspect of the present invention, in the first aspect, the target temperature for defrosting is determined to be the same temperature as the window glass of the vehicle when the vehicle speed is high, and the target temperature for defrosting is lower than that at the high vehicle speed when the vehicle speed is low. It is characterized in that it is corrected to a temperature higher by a predetermined value.

By the way, since the indoor heat exchanger (18) is forcibly ventilated even if the condensed water evaporates in the hot gas heating mode, the relative humidity of the air blown out from the indoor heat exchanger (18) is usually 80 to It is about 90%. Therefore, even if the air near the window glass is cooled by the window glass and has the same temperature as the window glass, according to claim 2, the relative humidity of the air near the window glass is 80 to 90%, which is the same as the air blown from the indoor heat exchanger. It only rises to the extent and does not cause fogging of the window glass.

According to a third aspect of the present invention, in the second aspect, the temperature of the vehicle window glass is calculated based on the outside air temperature and the temperature increase due to the air blown from the air conditioning case (22). And

Thus, the temperature of the window glass can be calculated by utilizing the existing sensor signal without the need for a dedicated temperature sensor for detecting the temperature of the window glass.

According to the invention described in claim 4, claim 1
In any one of No. 3 to No. 3, the temperature of blown air of the indoor heat exchanger (18) may be controlled by controlling the discharge capacity of the compressor (10). Here, the compressor (10)
The discharge capacity of the compressor is more specifically an intermittent control of the compressor operation,
It can be controlled by variably controlling the discharge capacity of the compressor, variably controlling the rotational speed of the compressor, or the like.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, at least the amount of condensed water in the indoor heat exchanger (18) in the cooling mode and the indoor heat exchange in the heating mode. The water retention amount is determined based on the evaporation amount of the condensed water in the device (18) and the discharge amount of the condensed water from the drain port (22a) of the air conditioning case (22) when the compressor (10) is in a stopped state. It is characterized by calculating.

Thus, the water retention amount can be accurately calculated by subtracting the evaporation amount in the heating mode and the drainage amount in the standing mode from the condensed water amount in the cooling mode.

In a sixth aspect of the present invention, in any one of the first to fifth aspects, the compressor (10) is driven by the vehicle engine (12), and the indoor heat exchange is performed in the air conditioning case (22). A hot water heat exchanger (24) for heating air using hot water from the vehicle engine (12) as a heat source is arranged downstream of the device (18).

As a result, the air heated by the indoor heat exchanger (18) is further heated by the hot water heat exchanger (24) and blown out into the passenger compartment to improve the heating performance of the passenger compartment. The present invention is thus preferably implemented in a combination of the auxiliary heating function of the indoor heat exchanger (18) and the main heating function of the hot water heat exchanger (24).

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

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 illustrates the overall configuration of a vehicle air conditioner according to the first embodiment. The compressor 10 is driven by a water-cooled vehicle engine 12 via an electromagnetic clutch 11, and is composed of, for example, a fixed capacity swash plate compressor.

The discharge side of the compressor 10 is connected to a condenser 14 via a cooling electromagnetic valve 13, and the outlet side of the condenser 14 is a liquid receiver 15 for separating the gas-liquid refrigerant and storing the liquid refrigerant. Connected. The condenser 14 is an outdoor heat exchanger that is disposed in the vehicle engine room together with the compressor 10 and the like and exchanges heat with the outside air (cooling air) blown by the electric cooling fan 14a.

The outlet side of the liquid receiver 15 is connected to a temperature type expansion valve 16 which constitutes a cooling decompression device. The outlet side of the temperature type expansion valve 16 is connected to the evaporator 1 via a check valve 17.
8 is connected. The outlet side of the evaporator 18 is connected to the suction side of the compressor 10 via an accumulator 19.

From the discharge side of the compressor 10 described above, the electromagnetic valve 13 for cooling, the condenser 14, the liquid receiver 15 and the thermal expansion valve 16
-> Check valve 17-> Evaporator 18-> The closed circuit that returns to the suction side of the compressor 10 via the accumulator 19 constitutes a normal refrigeration cycle C for cooling.

As is well known, the temperature type expansion valve 16 adjusts the valve opening degree (refrigerant flow rate) so that the superheat degree of the refrigerant at the outlet of the evaporator 18 is maintained at a predetermined value during the normal refrigeration cycle operation (in the cooling mode). To do. The accumulator 19 separates the gas-liquid of the refrigerant to store the liquid refrigerant, and the gas refrigerant to the compressor 1
At the same time as sucking to the 0 side, the oil dissolved in the liquid refrigerant near the bottom is sucked to the compressor 10 side.

On the other hand, a hot gas bypass passage 20 for bypassing the condenser 14 and the like is provided between the discharge side of the compressor 10 and the inlet side of the evaporator 18, and this bypass passage 2
At 0, a heating solenoid valve 21 and a throttle 21a are provided in series. The diaphragm 21a constitutes a heating decompression device, and can be composed of a fixed diaphragm such as an orifice or a capillary tube. A hot gas heater cycle H for heating is constituted by a closed circuit that returns from the discharge side of the compressor 10 to the intake side of the compressor 10 via the heating electromagnetic valve 21 → throttle 21a → evaporator 18 → accumulator 19.

The air conditioning case 22 of the vehicle air conditioner constitutes an air passage through which air flows toward the passenger compartment, and the air is blown inside the air conditioning case 22 by an electric air conditioning blower 23. Although the air-conditioning blower 23 is shown as an axial flow type for simplification of illustration, it is actually a centrifugal blower having a centrifugal fan, and this air-conditioning blower 23 is a blower motor 23a controlled by a blower drive circuit. Is driven to rotate. The amount of air blown by the blower 23 of the present embodiment can be switched continuously or stepwise by adjusting the blower control voltage applied to the blower motor 23a.

On the suction side of the air conditioner blower 23, an outside air suction port 70 for sucking in outside air (air outside the vehicle compartment), an inside air suction port 71 for sucking inside air (air inside the vehicle compartment), and an inside / outside air switching door. An (inside / outside air switching unit) 72 is provided. The inside / outside air switching door 72 is driven by an actuator such as a servomotor via a link mechanism (not shown), and at least the outside air mode for sucking the outside air from the outside air suction port 70 and the inside air mode for sucking the inside air from the inside air suction port 71 are used. Switch.

The evaporator 18 is an indoor heat exchanger installed in the air-conditioning case 22. In the cooling mode, the refrigerant circulates by the cooling refrigeration cycle C, and the evaporator 18 cools the refrigerant by absorbing heat. The blown air of the blower 23 is cooled. Further, in the heating mode, the evaporator 18 serves as a radiator because the high-temperature refrigerant gas (hot gas) from the hot gas bypass passage 20 flows in to heat the air.

In the air conditioning case 22, the evaporator 18
A drain port 22a for draining the condensed water generated in the evaporator 18 is provided in the lower part of the, and the condensed water is drained to the outside of the vehicle compartment through a drain pipe (not shown) connected to the drain port 22a.

In the air conditioning case 22, on the air downstream side of the evaporator 18, there is installed a hot water type heat exchanger 24 for heating, which heats the blown air by using hot water (engine cooling water) from the vehicle engine 12 as a heat source. There is. In the hot water circuit to the heating heat exchanger 24, a hot water valve 25 for controlling the hot water flow,
And a hot water pump (not shown) driven by the vehicle engine 12. As a result, hot water is circulated to the heating heat exchanger 24 via the hot water valve 25 by the operation of the hot water pump (not shown) driven by the engine.

By the way, a hot water heating heat exchanger 24
Is a main heating means for heating the interior of the vehicle, while the evaporator (indoor heat exchanger) 18 which is a radiator of the hot gas heater cycle H constitutes an auxiliary heating means.

On the other hand, on the most downstream side of the air in the air conditioning case 22, a defroster (DEF) outlet 3 for blowing out conditioned air (mainly warm air) toward the inner surface of the vehicle windshield.
1 and a face (FACE) outlet 3 for blowing out conditioned air (mainly cold air) toward the vehicle occupant's face (upper body)
2 and a foot (FOOT) outlet 3 for blowing out conditioned air (mainly warm air) toward the feet (lower body) of the vehicle occupant
3 is provided. Further, each of these outlets 31 to 3
A plurality of mode switching doors 34 to 3 for selectively opening and closing
6 is rotatably provided. The mode switching doors 34 to 36 constitute a blowout mode switching means and are driven by an actuator such as a servo motor via a link mechanism (not shown).

Electronic control unit for air conditioning (hereinafter referred to as ECU)
Reference numeral 26 is composed of a microcomputer and its peripheral circuits, and performs predetermined arithmetic processing according to a preset program to open / close the solenoid valves 13 and 21 and other electric devices (11, 14a, 23, 25, etc.). Control operation.

FIG. 2 is an electric control block diagram of the first embodiment. The ECU 26 includes a water temperature sensor 27a for the vehicle engine 12, an outside air temperature sensor 27b, an outlet air temperature sensor 27c for the evaporator 18, and a compressor discharge pressure. Pressure sensor 27
Detection signals are input from a sensor group such as d, an inside air temperature sensor 27e, a solar radiation sensor 27f that detects the amount of solar radiation into the vehicle interior, and a vehicle speed sensor 27g that detects the traveling speed of the vehicle.

Further, the operation signals of the following operation switch groups are input to the ECU 26 from the air conditioning operation panel 28 installed near the instrument panel in the vehicle compartment. That is, the air conditioner switch 29a issues a command to start or stop the compressor 10 in the refrigeration cycle, and serves as a cooling switch that sets a cooling mode. The hot gas switch 29b sets a heating mode by the hot gas heater cycle H, and functions as a heating switch.

Further, on the air conditioning operation panel 28, a blowing mode selector switch 29c for switching the blowing mode of the air conditioning,
Temperature setting switch (temperature setting means) 29d for setting the temperature inside the vehicle to a desired temperature, blower switch 29e for instructing on / off and air volume switching of the blower 23, inside / outside air switching for instructing switching between the outside air mode and the inside air mode Switch 2
9f etc. are installed.

Next, the operation of the present embodiment having the above structure will be described. First, the operation of the refrigeration cycle part will be described. When the air conditioner switch 29a is turned on and the cooling mode is set, the ECU 26 opens the cooling solenoid valve 13 and opens the heating solenoid valve 21. It is said that Therefore, when the electromagnetic clutch 11 is in the connected state and the compressor 10 is driven by the vehicle engine 12, the compressor 1
The discharged gas refrigerant of 0 passes through the cooling solenoid valve 13 in the open state and flows into the condenser 14.

In the condenser 14, the refrigerant is cooled and condensed by the outside air blown by the cooling fan 14a. Then, the refrigerant that has passed through the condenser 14 is separated into gas and liquid by the liquid receiver 15, and only the liquid refrigerant is decompressed by the thermal expansion valve 16 to be in a low temperature and low pressure gas-liquid two-phase state.

Next, the low-pressure refrigerant passes through the check valve 17, flows into the evaporator 18, and absorbs heat from the conditioned air blown by the blower 23 to be evaporated. The conditioned air cooled by the evaporator 18 is blown into the vehicle interior to cool the vehicle interior. Evaporator 1
The gas refrigerant evaporated in 8 is sucked into the compressor 10 via the accumulator 19 and compressed.

When the hot gas switch 29b is turned on and the heating mode is set by the hot gas heater cycle H in the winter, the ECU 26 causes the cooling solenoid valve 13 to operate.
Is closed, the heating solenoid valve 21 is opened, and the hot gas bypass passage 20 is opened. Therefore, after the high temperature discharge gas refrigerant (superheated gas refrigerant) of the compressor 10 passes through the heating electromagnetic valve 21 in the open state and is decompressed by the throttle 21a,
It flows into the evaporator 18. That is, the superheated gas refrigerant (hot gas) from the compressor 10 bypasses the condenser 14 and the like and is directly introduced into the evaporator 18.

At this time, the check valve 17 prevents the gas refrigerant from the hot gas bypass passage 20 from flowing to the thermal expansion valve 16 side. Therefore, the refrigeration cycle is performed by the compressor 10
Discharge side → heating solenoid valve 21 → throttle 21a → evaporator 18
→ Accumulator 19 → Operates in a closed circuit (hot gas heater cycle H) that returns to the suction side of the compressor 10.

Then, the overheated gas refrigerant, which has been decompressed by the throttle 21a, radiates heat to the blown air in the evaporator 18 to heat the blown air. Here, the amount of heat released from the gas refrigerant in the evaporator 18 corresponds to the amount of compression work of the compressor 10. The gas refrigerant radiating heat in the evaporator 18 is sucked into the compressor 10 via the accumulator 19 and compressed.

When the hot water temperature is low, such as immediately after the engine 12 is started, the air conditioning blower 23 is warmed up so as to start with a low air flow rate. By blowing hot water through the hot water valve 25 through the hot water heating heat exchanger 24, the blown air heated by the evaporator 18 can be further heated by the heat exchanger 24. Therefore, even in cold weather, it is possible to blow hot air having a higher temperature, which is heated by both the evaporator 18 and the hot water heating heat exchanger 24, into the vehicle interior.

Next, the capacity control of the hot gas heater cycle H in the heating mode according to the first embodiment will be specifically described with reference to FIG. The control routine of FIG.
It starts by starting 2 (turning on the ignition switch), and at step S10, it is determined whether the hot gas switch 29b of the air conditioning operation panel 28 is turned on (ON). When the hot gas switch 29b is turned on (ON), that is, when the hot gas heating mode is set, the process proceeds to step S20, and it is determined whether there is a water retention amount in the evaporator 18. Figure 5 shows the specific method for calculating the water retention capacity.
6 will be described later.

In step S20, when the water retention amount of the evaporator 18 becomes equal to or less than a predetermined minimum amount close to 0, it is determined that the water retention amount of the evaporator 18 does not exist. When the amount of water held in the evaporator 18 is low, even if the evaporator 18 acts as a radiator of hot gas, the condensed water does not evaporate in the evaporator 18, and therefore, there is no fear of clouding of the window glass. Therefore, in step S30, the electromagnetic clutch 11 is energized to bring the electromagnetic clutch 11 into the connected (ON) state. As a result, the compressor 10 is driven by the vehicle engine 12 via the electromagnetic clutch 11 and is in an operating (ON) state.

On the other hand, in step S20, the evaporator 1
If the water retention amount of No. 8 is greater than the predetermined minimum amount, it is determined that there is the water retention amount of the evaporator 18, the process proceeds to step S40, and the evaporator outlet air temperature Te is determined based on the window glass temperature Tws. It is determined whether the temperature is higher than the stop target temperature TEO. Here, the anti-fog target temperature TEO is set to a temperature equivalent to the temperature Tws of the window glass at a high vehicle speed for the reason described later, and the low fog target temperature TEO is switched to a temperature higher by a predetermined amount than the window glass temperature Tws at a low vehicle speed. .

The temperature sensor 27 measures the temperature Te of the air blown from the evaporator.
The temperature Tws of the window glass is the glass inner surface temperature, which will be described later.
It is calculated (estimated) based on the outside air temperature Tam and the temperature increase due to the air blown into the vehicle (warm air).

When Te> TEO, the process proceeds to step S50, where the energization of the electromagnetic clutch 11 is cut off (O
FF) to turn off the compressor 10. On the other hand, Te
When ≦ TEO, the process proceeds to step S30, and the electromagnetic clutch 11 is engaged (ON) to bring the compressor 10 into an operating (ON) state.

By intermittently controlling the operation of the compressor 10 as described above, the evaporator outlet air temperature Te can be controlled to a temperature equal to or lower than the fog prevention target temperature TEO. When the vehicle speed is high, the fog-prevention target temperature TEO is equal to the window glass temperature Tws. Therefore, the evaporator outlet air temperature Te is controlled to be equal to or lower than the window glass temperature Tws. So at first TEO =
The case of Tws will be described.

By the way, in order to prevent fogging of the window glass during heating, the outside air mode for introducing outside air having a low absolute humidity is usually selected as the inside / outside air intake mode. Then, during cold weather that requires the heating mode operation of the hot gas heater cycle H, low-temperature outside air near 0 ° C. is introduced into the evaporator 18. Relative humidity is originally high in low temperature outside air even if absolute humidity is low. In addition to this, when the condensed water evaporates in the evaporator 18, the relative humidity of the air blown from the evaporator is 85% to 90%.
It becomes a high value of about%.

The air blown from the evaporator is then heated by the hot water heat exchanger 24 to raise its temperature and then blown into the passenger compartment. When this blown air comes into contact with the low temperature window glass and is cooled to a temperature lower than the evaporator blown air temperature Te, it reaches the dew point to cause dew condensation, which causes fogging on the window glass.

However, according to the first embodiment, the evaporator 1
If there is a water retention amount of 8 and the vehicle speed is high, the operation of the compressor 10 is intermittently controlled by steps S40, S30, and S50 so that the evaporator outlet air temperature Te becomes equal to or lower than the window glass temperature Tws. Therefore, even if the air blown into the vehicle comes into contact with the low temperature window glass and is cooled to the same temperature as the window glass, the relative humidity is the value after the evaporator blows out (about 85% to 90%). It just rises to.

That is, the above steps S40, S30, S
In 50, the evaporator outlet air temperature Te can be controlled in a range in which the outlet air does not reach the dew point even if the outlet air is cooled by the window glass. As a result, even if condensed water evaporates in the evaporator 18, it is possible to reliably prevent fogging of the window glass.

FIG. 4 (a) illustrates the antifogging effect in the hot gas heating mode according to the first embodiment. The vertical axis represents the evaporator outlet temperature Te, and the horizontal axis represents the window glass temperature Tws. It is a thing. The window glass temperature Tws is an inner surface glass temperature on the vehicle interior side. The circles in the figure are in foot mode,
It is an actual vehicle evaluation value when the window glass (vehicle windshield) starts to become cloudy. Here, the foot mode is a blowing mode in which air is mainly blown from the foot outlet 33 to the foot portion of the vehicle compartment and a small amount of air is blown from the defroster outlet 31 to the inside of the window glass in the vehicle compartment.

The square mark is an actual vehicle evaluation value when the window glass (vehicle windshield) begins to become cloudy in the defroster mode in which air is blown from the defroster outlet 31 to the inside of the window glass in the vehicle compartment. In both the foot mode and the defroster mode, the air volume is set to a small air volume (Lo) state of about 150 m ³ / h. The relative humidity of the air blown from the evaporator is 90%.

Line A in FIG. 4A shows this relative humidity: 90
% Temperature of the window glass at which the air blown from the evaporator reaches the dew point Tws
Line, that is, the fogging limit line, the upper side of the fogging limit line A is the fogging region of the window glass, and the lower side is the clearing region.

Therefore, when there is an evaporator water holding capacity, as described above, the evaporator outlet temperature Te is changed to the window glass temperature Tws.
By maintaining the temperature below, the evaporator outlet temperature Te
Is always located in the clear region below the fogging limit line A, and it is possible to reliably prevent fogging of the window glass.

In the region where the window glass temperature Tws is lower than around -8 ° C, the evaporation amount of the condensed water in the evaporator 18 decreases even if the hot gas heating mode is executed, so that the fogging limit line A evaporates. It bends toward the high temperature side with respect to the outlet temperature Te, and the cloudy region becomes narrow.

FIG. 4B shows the relationship between the evaporator outlet temperature Te and the window glass temperature Tws when the window glass begins to become cloudy. Line A is the same as the fogging limit line A in FIG. 4A. is there. Evaporator outlet temperature Te is window glass temperature Tws
If the temperature is controlled so as to be equal to or lower than the temperature of the line A with respect to the change of, the fogging of the window glass can be prevented. Since the evaporator outlet temperature Te on the line A is slightly higher than the window glass temperature Tws, the evaporator outlet temperature Te is set to the window glass temperature Tws.
If it is controlled to be ws or less, it is possible to more reliably prevent fogging of the window glass.

As can be seen from FIGS. 4 (a) and 4 (b), in the region where the window glass temperature Tws is lower than around -8 ° C., the evaporator outlet temperature Te when the window glass begins to become cloudy with respect to the window glass temperature Tws. When the window glass temperature Tws is used as the anti-fog target temperature TEO in step S40 of FIG. 3, the value corrected to a higher temperature side than the actual window glass temperature in the above low temperature region is TEO.
It can be used as

Next, the step S30 of FIG. 3 will be captured and explained. In step S30, the electromagnetic clutch 11 is not simply left connected (ON), but is actually
The electromagnetic clutch 11 is intermittently controlled so that the discharge pressure Pd of the compressor 10 detected by the pressure sensor 27d becomes equal to or lower than a predetermined pressure (for example, 20 kg / cm ² G).
The operation of 0 is interrupted.

That is, if the discharge pressure Pd of the compressor 10 is less than or equal to a predetermined pressure, the electromagnetic clutch 11 is energized to operate the compressor 10. On the other hand, the discharge pressure P of the compressor 10
When d is higher than a predetermined value, the electromagnetic clutch 11 is de-energized and the compressor 10 is stopped. In this way the compressor 1
By intermittently controlling 0, the upper limit of the discharge pressure Pd of the compressor 10 in the heating mode of the hot gas heater cycle H can be controlled within the above predetermined pressure.
Preventing an abnormal rise in the discharge pressure Pd of the compressor 10,
The durable life of the compressor 10 can be improved.

In the first embodiment, the step S20 constitutes a judgment means for judging the presence / absence of the water retention amount in the evaporator 18, and the steps S40, S3.
0 and S50 constitute control means for controlling the temperature of air blown from the evaporator 18 in the heating mode.

Next, the concept of calculating the water retention amount of the evaporator 18 will be described with reference to FIG. FIG. 5 (a) shows the relationship between the change in the operating mode of the air conditioning refrigeration cycle during the operation of the vehicle engine and the accompanying change in the water retention capacity of the evaporator. When the cooling mode is set during the operation of the vehicle engine, the evaporation is performed. Condensed water is generated by the cooling and dehumidifying action of the cooler 18, so that the evaporator water retention amount increases in proportion to the operating time of the cooling mode (compressor operating time).

FIG. 5B shows a concrete example of the amount of condensed water in the cooling mode. This amount of condensed water is an amount per unit time (cc / min), and is a value obtained by subtracting the amount of condensed water discharged from the drainage port 22a of the air conditioning case 22 from the amount of condensed water generated in the evaporator 18. In FIG. 5B, the lower temperature is the temperature of the air sucked into the evaporator, and%
Is the relative humidity of the air drawn into the evaporator. When the temperature of the air sucked into the evaporator increases, the absolute humidity of the air sucked into the evaporator increases and the amount of condensed water increases.

In FIG. 5B, the lower Me2
Indicates that the air volume of the air conditioner blower 23 is the second intermediate air volume (in this example, about 280 m ³ / h). In addition,
The air volume of the air-conditioning blower 23 is low (Lo), first intermediate air volume (Me1), second intermediate air volume (Me2), large air volume (H).
It is possible to manually switch to four stages of i), and the second intermediate air volume (Me2) is the next largest air volume level after the large air volume (Hi).

Next, the compressor 10 is stopped during standing, and neither the cooling mode nor the hot gas heating mode is set. During this standing, the condensed water is drained from the drain port 22a of the air conditioning case 22. This drain port 2
The amount of waste water from 2a will reduce the amount of water retained by the evaporator. FIG. 5B shows that the amount of water retained by the evaporator decreases due to this amount of drainage water with the lapse of time when left standing. Here, the term “when left unattended” includes both the operation and the stop of the air conditioner blower 23, which means that the stop state of the compressor 10 is selected.

Since the drainage amount when left standing has a relationship that increases as the evaporator water retention amount increases, it can be calculated based on the water retention amount at the time of the drainage amount calculation in the standing (compressor stop) mode.

Next, when the hot gas heating mode is set, the heat dissipation effect of the evaporator 18 causes the condensed water to evaporate in the evaporator 18, so that the water retention amount decreases by the amount of the evaporation. Here, even in the hot gas heating mode, since the condensed water is drained from the drain port 22a of the air conditioning case 22, the evaporation amount in FIG. 5B is a value including the drain amount from the drain port 22a. The evaporation amount in the hot gas heating mode has a relationship of increasing as the evaporator outlet air temperature Te becomes higher.

From the above examination based on FIG. 5, the water retention capacity of the evaporator can be basically expressed by the following equation 1.

[0082]

[Equation 1] Evaporator water retention amount = condensed water amount−evaporation amount−drainage amount when left standing In addition, in FIG. 5, the water retention amount change in the case where the maximum retained amount (full water amount) of condensed water in the evaporator 18 is 250 cc Shows. The evaporator 18 is a laminated evaporator generally used in a vehicle air conditioner, and has a heat exchanger structure in which flat tubes configured by laminated plates and corrugated fins are combined. To be held on.

Next, a specific method of calculating the water retention capacity of the evaporator will be described with reference to FIG. 6. The control routine of FIG. 6 starts when the vehicle engine 12 is started (the ignition switch is turned on), and while the vehicle engine 12 is operating. The evaporator water retention amount is constantly calculated, and the calculated value of the evaporator water retention amount is updated at predetermined time intervals (for example, every one minute).

In FIG. 6, first, in step S100, the stored water retention amount is read. This stored water retention amount is an evaporator water retention amount calculated immediately before the engine was stopped the last time and stored in the storage means of the ECU 26.

In the next step S200, it is determined whether the cooling mode is set. Specifically, whether or not the cooling mode is set can be determined based on whether or not the air conditioner switch 29a is turned on. When the cooling mode is set, the process proceeds to step S300, and the water retention amount in the cooling mode is water retention amount = memorized water retention amount +
Calculate with the formula of the amount of condensed water.

Here, the amount of condensed water in the cooling mode is, specifically, as the absolute humidity of the air sucked into the evaporator is higher,
The larger the compressor (electromagnetic clutch) ON time in the cooling mode is, the larger the relationship is. Therefore, the amount of condensed water can be calculated from the information related to the absolute humidity of the air sucked into the evaporator and the compressor ON time. Here, the information related to the absolute humidity of the air taken in by the evaporator is, specifically,
It is the inside / outside air intake mode of the air conditioning and the outside air temperature, and when the inside / outside air intake mode is the inside air mode, it corresponds to the case where the absolute humidity of the intake air of the evaporator is the highest, and the amount of condensed water per unit time becomes the maximum amount ( For example, 8.3 cc / min)
And

In the outside air mode, the outside air temperature is 20 ° C.
In the above case, the amount of condensed water per unit time is set to the maximum amount (for example, 8.3 cc / min) as in the inside air mode. When the outside air temperature decreases in the outside air mode, the amount of condensed water gradually decreases, and when the outside air temperature is less than 20 ° C. and 10 ° C. or more, the amount of condensed water per unit time is, for example, 4.2 cc /
Set to min. And the outside air temperature is 10 ° C in the outside air mode.
Is less than 5 ° C, the amount of condensed water per unit time is, for example, 2.8 cc / min, and when the outside air temperature is less than 5 ° C in the outside air mode, the amount of condensed water per unit time is the minimum amount. (For example, 2.1 cc / min).

In step S300, the amount of condensed water in the cooling mode is calculated as described above, and the amount of condensed water is added to the stored water holding amount to calculate the water holding amount in the cooling mode. The amount of condensed water in the cooling mode also has a correlation with the amount of air sucked into the evaporator, and the amount of condensed water increases as the amount of air increases. Therefore, in order to improve the accuracy of the condensed water amount calculation, the condensed water amount calculated as described above may be corrected so as to increase with an increase in the air flow amount.

On the other hand, if the decision in step S200 is NO, the process advances to step S400 to decide whether or not the hot gas heating mode is set. Specifically, whether or not the hot gas heating mode is set can be determined based on whether or not the hot gas switch 29b is turned on. When the hot gas heating mode is set, the process proceeds to step S500, and the water retention amount in the hot gas heating mode is calculated by the formula of water retention amount = memorized water retention amount-evaporation amount.

Here, in the hot gas heating mode, the relative humidity decreases as the evaporator outlet temperature Te increases, so the evaporation amount per unit time (cc / min) is proportional to the increase in the evaporator outlet temperature Te. And there is an increasing relationship. Therefore, the evaporation amount in the hot gas heating mode can be calculated based on the map that increases in proportion to the rise of the evaporator outlet temperature Te as shown in FIG.

On the other hand, when the determination in step S400 is NO, it means that neither the cooling mode nor the hot gas heating mode is in effect, that is, when the compressor 10 is stopped, and at this time, the process proceeds to step S600. The water retention capacity when left undisturbed is calculated by the formula of water retention capacity = memory water retention capacity-drainage capacity. Here, the amount of drainage when left standing is the amount of condensed water drained from the drainage port 22a to the outside of the air conditioning case 22, and the amount of drainage water from the drainage port 22a per unit time (cc / mi).
Since n) increases as the amount of water held in the evaporator increases, the amount of waste water in the neglect mode can be calculated based on the amount of water held in the evaporator at the time of calculating the amount of waste water.

As the drainage amount when left unattended, only the drainage amount when left unattended while the vehicle engine is operating has been described with reference to FIG. 5, but if the drainage amount when left unattended when the vehicle engine is stopped is also calculated, the amount of water retained by the evaporator can be calculated. The accuracy can be improved.

Further, there are cases where the cooling mode, the hot gas heating mode, and the leaving mode are switched while the vehicle engine 12 is operating. In that case, steps S300 and S5 are performed.
In S00 and S600, the last water retention amount calculated in the previous mode may be used as the stored water retention amount.

By the way, in the determination of step S40 in FIG. 3, the window glass temperature Tws used as the anti-fog target temperature TEO is detected directly by the dedicated temperature sensor by installing a dedicated temperature sensor on the inner surface of the window glass. However, this method causes an increase in cost due to the addition of the sensor. Therefore, in the present embodiment, the window temperature Tws is calculated (estimated) using the existing sensor signal of the air conditioner.

That is, the window glass temperature Tws is the same as the outside air temperature Tam in the initial state before the start of air conditioning. After that, when the warm air is blown into the vehicle interior by executing the heating mode, the temperature of the window glass Tw is increased by the warm air blow.
s rises. Therefore, assuming that the increase in the window glass temperature due to the warm air blowing is ΔTws, the window glass temperature Tws is T
It can be calculated by the formula of ws = Tam + ΔTws.

Here, in the hot gas heating mode, the hot air blown into the vehicle compartment is heated by the hot water heating heat exchanger 24 after passing through the evaporator 18, so the hot air temperature greatly depends on the hot water temperature. Therefore, the increase ΔTws of the window glass temperature due to the blowing of warm air has a relationship of increasing in proportion to the increase of the engine water temperature (the temperature of the hot water circulating through the hot water heating heat exchanger 24) as shown in FIG. 7. Therefore, the increase ΔTws of the window glass temperature due to the blowing of warm air can be calculated based on the engine water temperature (warm water temperature).

Increase in window glass temperature due to warm air blowing ΔT
Since ws is affected not only by the temperature of warm air but also by the amount of warm air flowing into the inside of the window glass, in order to improve the calculation accuracy of the increase ΔTws of the window glass temperature, the increase in the amount of warm air increases. It is better to correct so that ΔTws increases. The degree of influence of the warm air volume can be determined by the air blowing level of the air conditioning blower 23 and the blowing mode.

By the way, the overall operation according to the present embodiment has been described above. In the present embodiment, priority is given to the anti-fog performance for the vehicle window glass and the vehicle interior heating performance at the low vehicle speed and the high vehicle speed. In view of the difference in temperature, the blown air temperature Te of the evaporator 18 in the hot gas heating mode is switch-controlled depending on whether the vehicle speed is low or high.

That is, when the vehicle speed is lower than a predetermined speed, for example, less than 20 km / h, the rotation speed of the vehicle engine 12 decreases → the rotation speed of an engine-driven hot water pump (not shown) decreases → the hot water flow rate to the heating heat exchanger 12 decreases. Occurs, and the heating performance of the heating heat exchanger 12 deteriorates. On the other hand, when the vehicle speed is higher than the predetermined speed, the flow rate of hot water to the heating heat exchanger 12 increases due to the increase in the rotation speed of the vehicle engine 12, and the heating performance of the heating heat exchanger 12 increases.

On the other hand, considering the fogging of the vehicle window glass, the temperature of the vehicle window glass is high on the lower side near the opening position of the defroster outlet 31, and the higher the vehicle window glass is, the lower the window glass temperature becomes. It will be easier. Also,
At low vehicle speeds, the driver has more leeway in driving operations than at high vehicle speeds.Therefore, even after partial fog on the upper part of the vehicle window glass, defrosting operation on the window glass, for example, blowing mode There is time to remove the fog on the window glass by performing operations such as switching to the defroster mode.

On the contrary, when the vehicle speed is high, there is no room for the driver to operate the vehicle, and even if it is partially clouded on the upper side of the window glass of the vehicle, there is a possibility of causing a danger due to the narrowed driving visibility. is there. Therefore, it is necessary to surely prevent the window glass from being fogged at high vehicle speeds.

That is, it is better to give priority to the anti-fog of the window glass at the high vehicle speed, and to give priority to the improvement of the hot gas heating capacity than the anti-fog of the window glass at the low vehicle speed.

Therefore, in the present embodiment, the evaporator 18 in the case where there is a water holding amount in the hot gas heating mode.
As shown in FIG. 8, the vehicle speed sensor 2 does not always have the frost prevention target temperature TEO of the vehicle window temperature constant.
Based on the vehicle speed signal detected by 7 g, it is divided into low vehicle speed and high vehicle speed, and the fog prevention target temperature T at high vehicle speed
EO is set to be low, and the target temperature TE for fog prevention at low vehicle speed is set.
O is set to be switched higher.

Specifically, at high vehicle speed (20 km in this example)
/ H) or more) is set to a temperature equal to the estimated window glass temperature TWS, and the actual blown air temperature Te of the evaporator 18 is controlled to a temperature equal to the window glass temperature TWS. As a result, as described above, even at a high vehicle speed, even if the temperature of the air blown into the vehicle compartment is cooled to the same temperature as the vehicle window glass, the dew point does not reach and the occurrence of fogging on the window glass can be reliably prevented.

On the other hand, when the vehicle speed is low (less than 20 km / h in this example), the fog-prevention target temperature TEO is set to a temperature several degrees higher than that at the high vehicle speed. Te can be increased by an amount corresponding to the increase in the target temperature, and the increase in the blown air temperature Te can improve the hot gas heating capacity at low vehicle speeds.

When the vehicle speed is low, the temperature Te of the air blown from the evaporator is set higher than the window glass temperature TWS, so that the window glass temperature TWS is liable to rise. However, since the vehicle speed is low, there is no practical problem for the above reason.

(Other Embodiments) In the above-described embodiment, when the vehicle speed is less than the predetermined speed of 20 km / h, the vehicle speed is low. However, the predetermined speed depends on the driving condition of each vehicle type. Of course, various changes may be made. Therefore, the value of the predetermined speed may be set to a value as close to 0 as possible, and the low vehicle speed may be substantially stopped only (at idle). That is, the low vehicle speed referred to in the present specification includes a case where the vehicle is stopped (idle) only.

In the above-described embodiment, the air conditioning operation panel 28 is provided with the dedicated hot gas switch 29b manually operated by the passenger, and the hot gas heating mode is set by turning on the hot gas switch 29b. Instead of providing such a manually operated dedicated switch 29b, for example, the ECU 26 may determine the maximum heating state or the like and automatically start the hot gas heating mode.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing an overall configuration of an embodiment of the present invention.

FIG. 2 is a block diagram of electrical control of one embodiment of the present invention.

FIG. 3 is a flowchart showing compressor control in a hot gas heating mode according to an embodiment of the present invention.

FIG. 4A is a graph of experimental results showing an antifogging effect of the evaporator blowout temperature control in the hot gas heating mode according to the embodiment of the present invention, and FIG. 4B is an evaporator blowout in the hot gas heating mode. It is a temperature control characteristic diagram.

FIG. 5 is an explanatory diagram of the concept of calculating the water retention capacity of an evaporator according to an embodiment of the present invention.

FIG. 6 is a flowchart showing a method for calculating an evaporator water retention amount according to an embodiment of the present invention.

FIG. 7 is a characteristic diagram showing a relationship between an increase in glass temperature and engine water temperature in one embodiment of the present invention.

FIG. 8 is a characteristic diagram showing a specific example of setting of a fog-preventing target temperature of an evaporator outlet temperature in a hot gas heating mode according to an embodiment of the present invention.

[Explanation of symbols]

10 ... Compressor, 14 ... Condenser (outdoor heat exchanger), 16 ...
Temperature type expansion valve (pressure reducing device for cooling), 18 ... Evaporator (indoor heat exchanger), 20 ... Hot gas bypass passage, 21a ...
Aperture (pressure reducing device for heating), C ... Refrigeration cycle for cooling, H
… Hot gas heater cycle.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masahiro Shoji             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Car Co., Ltd.

Claims (6)

[Claims] 1. A refrigerant discharged from a compressor (10),
Cooling in which the indoor heat exchanger (18) is operated as an evaporator by returning to the compressor (10) through the outdoor heat exchanger (14), the cooling decompression device (16) and the indoor heat exchanger (18). Refrigeration cycle (C) and refrigerant discharged from the compressor (10) bypasses the outdoor heat exchanger (14) and passes through the indoor heat exchanger (18) to the compressor (10). By returning it, the hot gas heater cycle (H) that operates the indoor heat exchanger (18) as a radiator is switchable, and air flows through the indoor heat exchanger (18) toward the passenger compartment. It is arranged in an air-conditioning case (22) to execute a cooling mode by blowing out the air cooled by the indoor heat exchanger (18) by the cooling refrigeration cycle (C) into the passenger compartment, and the hot gas. Hey The heating mode is executed by blowing the air heated in the indoor heat exchanger (18) into the vehicle compartment by the cycle (H), and further, the water retention amount of the indoor heat exchanger (18) is changed. The determination means (S20) for determining the presence or absence, and the indoor heat exchanger (1 when the determination means (S20) determines that there is a water retention amount in the heating mode.
8) As the target temperature of the blown air, the air conditioning case (2
A target temperature for defrosting is set so that the air blown out from 2) does not reach the dew point even if it is cooled by the vehicle window glass, and the temperature of air blown out from the indoor heat exchanger (18) is set to be equal to or lower than the target temperature for defrosting. Control means (S
40, S30, S50), and corrects the fog-preventing target temperature at a low vehicle speed to a higher temperature side than at a high vehicle speed. 2. When the vehicle speed is high, the fog-prevention target temperature is set equal to that of the vehicle window glass, and when the vehicle speed is low, the fog-prevention target temperature is corrected to a temperature higher by a predetermined value than when the vehicle speed is high. The vehicle air conditioner according to claim 1, wherein the air conditioner is a vehicle air conditioner. 3. The temperature of the vehicle window glass is set to the outside air temperature,
The vehicle air conditioner according to claim 2, wherein the air conditioner is calculated on the basis of a temperature increase due to the air blown out from the air conditioning case (22). 4. The blown air temperature of the indoor heat exchanger (18) is controlled by controlling the discharge capacity of the compressor (10). The vehicle air conditioner described. 5. At least the amount of condensed water in the indoor heat exchanger (18) in the cooling mode, the amount of condensed water evaporated in the indoor heat exchanger (18) in the heating mode, and the compression. 5. The water retention amount is calculated based on a drainage amount of condensed water from a drainage port (22a) of the air conditioning case (22) when the machine (10) is in a stopped state and left. The vehicle air conditioner according to any one of 1. 6. The compressor (10) is a vehicle engine (1
2), and a hot water heat exchanger (24) that heats air by using hot water from the vehicle engine (12) as a heat source downstream of the indoor heat exchanger (18) in the air conditioning case (22). )
The vehicle air conditioner according to any one of claims 1 to 5, wherein: