JP2007283829A - Air conditioner for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To further improve fuel consumption by lengthening engine stopping time. <P>SOLUTION: An engine-on demand is prevented even when there is sufficient preheating of water temperature and the fuel consumption is further improved by lengthening the engine stopping time better than conventional technology by the engine-on demand when it becomes specified water temperature hard to maintain target blowout temperature (TAO) (210, 212), by canceling the engine-on demand (216) and controlling opening of an air mix damper to return it to 100%, when the opening of the air mix damper is less than 100%, that is, in the state where cold air and hot air are mixed when the engine-on demand is carried out (200 to 208, 214). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle air conditioner, and more particularly to a vehicle air conditioner mounted on a vehicle such as a hybrid vehicle that stops an engine when the vehicle is stopped.

  There is a vehicle in which idling stop control is performed to stop the idling and improve fuel efficiency when traveling is stopped at an intersection or the like. For example, in a vehicle equipped with an engine and a motor as power sources, the engine is stopped when the vehicle is stopped to improve fuel efficiency.

  On the other hand, since the vehicle air conditioner performs heating using the heat of engine cooling water, a desired heating effect cannot be obtained when the cooling water temperature is low. That is, in a vehicle that performs the idling stop control as described above and a vehicle such as a hybrid vehicle that has a mode in which the motor runs while running, if the cooling water temperature decreases, the heating effect cannot be obtained. .

Therefore, the engine is stopped and the engine is started based on a predetermined threshold value of the engine cooling water temperature according to the target outlet temperature (TAO) of the vehicle air conditioner, and the temperature drop of the cooling water is suppressed and heating is performed. It has been proposed to obtain an effect. For example, in the technique described in Patent Document 1, the coolant temperature at which engine start is required is set as the target air temperature (TAO) of the vehicle air conditioner is higher. As a result, the engine stop time can be extended to improve fuel efficiency.
JP 2002-211138 A

  However, as in the technique described in Patent Document 1, in a vehicle air conditioner that stops and starts an engine based on a predetermined threshold temperature of engine cooling water according to a target blowing temperature, The air passing through the heater core that passes through the heater core and the evaporator passing air that passes through the evaporator serving as the refrigerant passage may be mixed and air-conditioned.In this case, the air cooled by the evaporator Since they are mixed, the engine is wasted and the cooling water temperature is raised to maintain the heating temperature (target blowout temperature), resulting in wasted fuel consumption and improved vehicle fuel efficiency. There is room for improvement in control.

  The present invention has been made in consideration of the above-described facts, and an object of the present invention is to further improve fuel efficiency by extending the engine stop time.

  In order to achieve the above-mentioned object, the invention according to claim 1 is a method for calculating a target blowing temperature of air-conditioning air for air-conditioning a vehicle interior and mixing the cold air and hot air using the heat of engine cooling water. A vehicle air conditioner that air-conditions a vehicle interior so as to achieve the calculated target blow temperature according to the mixing state by the means, and a temperature of engine cooling water that is predetermined according to the target blow temperature is equal to or less than a threshold value In this case, engine start request means for making an engine start request for maintaining the heating capacity, determination means for determining the mixing state of the cold air and the hot air by the mixing means, and the mixing means by the determination means Engine start prohibiting means for prohibiting the engine start request when it is determined that hot air is mixed.

  According to the first aspect of the present invention, for example, the vehicle interior temperature, the outside air temperature, the amount of solar radiation, and the like are detected, and the target blowing temperature of the conditioned air to obtain a preset temperature is calculated. In accordance with the mixing state of the mixing means that mixes the warm air, the passenger compartment is air-conditioned so that the calculated target blowing temperature is reached.

  Further, in a vehicle such as a hybrid vehicle, since the engine is stopped and the motor is driven, the temperature of the cooling water serving as the heat source of the hot air is lowered. Therefore, the engine predetermined according to the target blowing temperature is used. When the temperature of the cooling water is equal to or lower than the threshold value, an engine start request for maintaining the heating capacity is made by the engine start request means.

  In such a vehicle air conditioner, as described above, even when the cold air and the hot air are mixed by the mixing means, if the temperature of the engine cooling water decreases, the heating capacity is maintained in the current mixing state of the mixing means. In order to do so, an engine start request is made.

  Therefore, when the determination unit determines the mixing state of the cold air and the hot air by the mixing unit, and the determination unit determines that the cold air and the hot air are mixed in the mixing state of the mixing unit, an engine start request is issued. It is prohibited by the engine start prohibiting means. As a result, it is possible to prevent the engine start request from being made even if the engine water temperature has sufficient residual heat, so that the engine stop time can be made longer than that of the prior art and further fuel economy can be improved.

  When the engine start request is prohibited by the engine start prohibiting means, as in the second aspect of the present invention, a setting means is further provided, and the temperature of the engine coolant that makes the engine start request is set from the threshold value. You may make it set low. This makes it possible to lengthen the engine stop time while maintaining the heating capacity.

  Further, when the engine start request is prohibited by the engine start prohibiting means, as in the third aspect of the present invention, the engine control apparatus further includes a mixing state control means, and the mixing state by the mixing means is high in the ratio of hot air. The mixing means may be controlled so as to maintain the target blowing temperature, and as in the invention described in claim 4, the cooling water circulation control means is further provided so that the engine cooling water can be supplied even when the engine is stopped. You may make it maintain the target blowing temperature by controlling the electric water pump which can circulate.

  As described above, according to the present invention, when an engine start request is made, if it is determined that the mixed state is a mixture of cold air and hot air, the engine start request is canceled. Since it is possible to prevent an engine start request even when there is sufficient remaining heat of the engine water temperature, there is an effect that it is possible to further improve fuel efficiency by extending the engine stop time.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a vehicle air conditioner according to an embodiment of the present invention. The vehicle air conditioner 10 according to the present embodiment will be described as being mounted on a hybrid vehicle and capable of air conditioning in the vehicle compartment even when the engine is stopped.

  In the vehicle air conditioner 10 according to the embodiment of the present invention, a refrigerant circulation path including a compressor 12, a condenser 14, an expansion valve 16, and an evaporator 18 constitutes a refrigeration cycle.

  The evaporator 18 cools the air passing through the evaporator 18 (hereinafter referred to as air after the evaporator) by evaporating the refrigerant that has been compressed and liquefied. At this time, the evaporator 18 cools the passing air so as to condense moisture in the air, whereby the air after the evaporator 18 is dehumidified.

  The expansion valve 16 provided on the upstream side of the evaporator 18 is configured to supply the liquefied refrigerant to the evaporator in a mist state by rapidly reducing the pressure of the liquefied refrigerant, whereby the refrigerant in the evaporator 18 is supplied. Vaporization efficiency is improved.

  In the present embodiment, the compressor 12 of the vehicle air conditioner 10 is an electric compressor so that the motor 20 can circulate the refrigerant even when the power of the vehicle (for example, an engine or a motor) is not operated. It is configured. When the vehicle power is operating, the compressor 12 may be driven by the vehicle power. Moreover, when using the motive power of a vehicle, you may make it apply not a motorized compressor but a mechanical compressor.

  The evaporator 18 of the vehicle air conditioner 10 is provided inside the air conditioning duct 22. The air conditioning duct 22 is open at both ends, and air inlets 24 and 26 are formed at one opening end. Further, a plurality of air outlets 28 (28A, 28B, and 28C are shown as an example in the present embodiment) opened toward the vehicle interior are formed at the other opening end.

  The air suction port 26 communicates with the outside of the vehicle and can introduce outside air into the air conditioning duct 22. Further, the air suction port 24 communicates with the vehicle interior, and air (inside air) can be introduced into the air conditioning duct 22 from the lower portion of the vehicle interior. In this embodiment, the air outlet 28 includes a defroster outlet 28A (DEF) that blows air toward the windshield glass, a side that can blow air toward the upper part of the vehicle interior, and a center register outlet 28B ( Vent), a foot outlet 28C (Heat) that blows out air toward the lower part of the vehicle interior.

  In the air conditioning duct 22, a blower fan 27 is provided between the evaporator 18 and the air suction ports 24 and 26. A suction port switching damper 30 is provided in the vicinity of the air suction ports 24 and 26. The suction port switching damper 30 exclusively opens and closes the air suction ports 24 and 26 by the operation of the suction port switching damper actuator 32.

  The blower fan 27 is rotated by driving of the blower motor 34, sucked into the air conditioning duct 22 from the air suction port 24 to the air suction port 26, and further sends this air toward the evaporator 18. At this time, outside air or inside air is introduced into the air conditioning duct 22 in accordance with the open / closed state of the air suction ports 24 and 26 by the suction port switching damper 30. That is, the inside air circulation mode and the outside air introduction mode are switched by the suction port switching damper 30.

  An air mix damper 36 and a heater core 38 are provided downstream of the evaporator 18. The air mix damper 36 is rotated by driving the air mix damper actuator 40 to adjust the amount of air after the evaporator 18 that passes through the heater core 38 and the amount that bypasses the heater core 38. The engine cooling water circulates in the heater core 38 and heats the air guided by the air mix damper 36 using the heat of the engine cooling water.

  The air after the evaporator 18 is guided to the heater core 38 according to the opening degree of the air mix damper 36 and heated, and further mixed with the air not heated by the heater core 38 and then sent to the air outlet 28. Is done. In the vehicle air conditioner 10, the air mix damper 36 is controlled to adjust the mixed state of the cool air after the evaporator 18 and the warm air heated by the heater core 38, so that the air blower 28 is directed toward the vehicle interior. Adjust the temperature of the blown out air.

  In the vicinity of the air outlet 28, an outlet switching damper 42 is provided. In the vehicle air conditioner 10, the air outlets 28 </ b> A, 28 </ b> B, and 28 </ b> C are opened and closed by the outlet switching damper 42, so that the temperature-adjusted air can be blown out from a desired position into the vehicle interior. The operation of the air outlet switching damper 42 is performed by driving the air outlet switching damper actuator 44 in accordance with the operation mode in which the vehicle air conditioner 10 is set.

  Further, the vehicle air conditioner 10 includes an air conditioner ECU 46 for performing various controls of the vehicle air conditioner 10. The air conditioner ECU 46 includes a blower fan speed air conditioner ECU 48 that controls the rotation speed of the blower fan 27, a suction port switching damper actuator 32, an air mix damper actuator 40, a blowout port switching damper actuator 44, and a motor that rotationally drives the compressor 12. 20 is connected to a control switch 50, an outside air temperature sensor 52, a vehicle interior temperature sensor 54, a solar radiation sensor 56, and a post-evaporator temperature sensor 60, and the temperature setting of the vehicle air conditioner 10 and the selection of the outlet 28. The temperature setting device 58 etc. for performing etc. are connected, The detection value of the outside temperature sensor 52, the vehicle interior temperature sensor 54, the solar radiation sensor 56, and the evaporator post-temperature sensor 60 is input into the air-conditioner ECU46, and detection of each sensor is carried out. The temperature setting device 58 is set based on the value. Has thus performs various controls in accordance with the equal. As the blower fan speed air conditioner ECU 48, a power transistor or the like can be applied. When the power transistor is applied, the rotation of the blower fan 27 is changed by changing the duty ratio of the voltage applied to the base of the power transistor. It is possible to change the speed.

  Furthermore, the engine ECU 62 is connected to the air conditioner ECU 46, and the detection result of the engine water temperature input to the engine ECU 62 can be acquired. The vehicle air conditioner 10 according to the present embodiment is a hybrid vehicle or the like. Since it is mounted on a vehicle and the engine is turned off when the motor is running or stopped, and the engine cooling water temperature decreases, the heating effect cannot be obtained. Therefore, based on the engine water temperature, the engine ECU 62 An engine on request and an engine off request are made.

  Specifically, the air conditioner ECU 46 stores an engine on / off request map that includes an engine on request threshold value and an engine off request threshold value of the engine water temperature that are predetermined according to the target outlet temperature (TAO). Based on the above, an engine-on request and an engine-off request are made to the engine ECU 62. FIG. 2 shows an example of an engine on / off request map for a predetermined threshold value of the engine water temperature according to the target outlet temperature. The solid line in FIG. 2 indicates the engine-off request threshold, the upper side in FIG. 2 of the solid line is the engine-off request region, the dotted line in FIG. 2 indicates the engine-on request threshold, and the lower line in FIG. A region between the solid line and the dotted line is a hysteresis region for preventing on / off chattering.

  Next, the operation of the vehicle air conditioner 10 configured as described above according to the embodiment of the present invention will be described.

  The vehicle air conditioner 10 according to the present embodiment is configured to perform air conditioning control (automatic air conditioning control) so as to keep the temperature in the vehicle interior at a predetermined set value based on the detection results of each sensor. The automatic air conditioner control will be described. FIG. 3 is a flowchart showing an example of the flow of automatic air conditioner control performed by the air conditioner ECU 46.

  When an air conditioning start instruction is issued by the temperature setting device 58 or the like, in step 100, detected values detected by respective sensor values such as the outside air temperature sensor 52, the vehicle interior temperature sensor 54, the solar radiation sensor 56, the post-evaporator temperature sensor 60, and the like. And the temperature set by the temperature setting device 58 are read.

  Subsequently, in step 102, the target blowing temperature (TAO) is calculated, and the routine proceeds to step 104. TAO is calculated using the following equation.

TAO = K1 * Tset-K2 * Tr-K3 * To-K4 * ST + C
Here, Tset is the set temperature, Tr is the passenger compartment temperature, To is the outside air temperature, ST is the amount of solar radiation, and K1, K2, K3, K4, and C are constants.

  In step 104, the opening degree of the air mix damper (A / M) 36 is calculated. Specifically, in order to control the blowout temperature to be the target blowout temperature, the mixing ratio (hot air / cold air) r, which is the ratio of the warm air passing through the heater core 38 and the cold air bypassing the heater core 38, is Calculated by the formula.

r = (TAO−Te) / (Th−Te)
Te represents the post-evaporator air temperature detected by a sensor provided after the evaporator 18, and Th represents the air temperature immediately after the heater core 38. In this embodiment, Th is calculated using the following equation.

Th = A × Tw + (1−A) × Te
Here, Tw indicates the temperature of the engine cooling water, and A indicates a constant of 1 or less.

  Next, the opening degree S of the air mix damper 36 at which the calculated mixing ratio r is obtained is calculated by the following equation.

S = F1 (r)
In addition, F1 (x) represents the function of the opening degree S of the air mix damper 36, and F1 (r) represents the opening degree of the air mix damper 36 in the case of the mixture ratio r.

  Next, at step 106, the air mix damper actuator 40 is driven so that the calculated opening of the air mix damper 36 is reached, and the routine proceeds to step 108.

  In step 108, the voltage to be applied to the blower motor 34 of the blower fan 27 is calculated from the target blow temperature in accordance with a predetermined map, and a signal is output to the blower fan speed control device 48, so as to correspond to the target blow temperature. The process proceeds to step 110.

  In step 110, it is determined whether the air conditioner is off. In this determination, it is determined whether or not the stop of air conditioning is instructed by the temperature setting device 58 or the like. If the determination is negative, the process returns to step 100 and the above processing is repeated, and the determination in step 110 is affirmative. When it is done, the process is terminated.

  By the way, since the vehicle air conditioner 10 according to the embodiment of the present invention is mounted on a hybrid vehicle or the like, the engine may be stopped and run with a motor or the like. Since heating is performed using heat, the heating effect cannot be obtained if the engine stop time becomes long. Therefore, an engine on / off request is output from the air conditioner ECU 46 to the engine ECU 62 to prevent a decrease in the temperature of the engine cooling water. Performs on / off request control.

  However, in the conventional engine on / off request control, an engine on / off request is made based on a predetermined water temperature threshold according to the target blow-off temperature (TAO), and therefore the air mix damper 36 is adjusted in opening to mix cold air. Even if the water temperature is lowered, an engine-on request is made and the engine cooling water itself makes an engine-on request even though there is sufficient residual heat, resulting in wasted fuel consumption.

  FIG. 4 shows changes over time in target blowing temperature (TAO), heater blowing temperature, water temperature (TWE), and opening degree (SW) of the air mix damper 36 when the vehicle arbitrarily travels while performing automatic air-conditioning control. It is a graph which shows. For example, in the automatic air conditioner control, when the engine is started and the water temperature (TWE) exceeds a predetermined water temperature, rotation of the blower motor 34 is started and the blowing temperature rises with time. (TAO) decreases. In the case of FIG. 4, the adjustment of the air mix damper opening (SW) is started about 27 minutes later, and the target blowout temperature is adjusted. While the air mix damper opening SW is being adjusted, the water temperature has sufficient heat. At this time, if an engine-on request is made, wasteful fuel consumption occurs. Thus, in the present embodiment, when the opening degree of the air mix damper 36 is being adjusted, engine on / off request control is performed so as to cancel the engine on request.

  FIG. 5 is a flowchart showing an example of the flow of engine on / off request control performed by the air conditioner ECU 46 of the vehicle air conditioner 10 according to the embodiment of the present invention. Note that the engine on / off request control in FIG. 5 will be described as ending with the end of the automatic air conditioner control.

  When the above-described automatic air conditioner control is started, in step 200, the current target outlet temperature (TAO) calculated in step 104 is read, and the routine proceeds to step 202.

  In step 202, it is determined whether or not the read target outlet temperature (TAO) is 40 ° C. or higher. If the determination is negative, the process proceeds to step 204. If the determination is affirmative, the process proceeds to step 206.

  In step 204, based on the engine on / off request map shown in FIG. 4, an engine on / off request is sent to the engine ECU 62, and the process returns to step 200 to repeat the above-described processing. That is, the engine ECU 62 controls engine on / off in response to an engine on request and an engine off request requested from the air conditioner ECU 46.

  On the other hand, when the determination in step 202 is affirmed and the routine proceeds to step 206, the opening degree of the air mix damper (A / M) calculated in step 104 is read and the routine proceeds to step 208.

  In step 208, it is determined whether or not the opening degree of the air mix damper (A / M) is less than 100% (the heating side fully open state where all the air after the evaporator 18 passes through the heater core 38). If the result is negative, the process proceeds to step 204 described above. If the result is positive, the process proceeds to step 210.

  In step 210, the engine water temperature is acquired from the engine ECU 62, the process proceeds to step 212, and it is determined whether or not the water temperature is equal to or higher than a predetermined water temperature. The predetermined water temperature is the lowest water temperature at which the target blowing temperature (TAO) can be maintained, and a predetermined value corresponding to the target blowing temperature (TAO) is stored in the air conditioner ECU 46 as a predetermined value. For example, the air conditioner ECU 46 stores a threshold value for making an engine on / off request at a temperature lower than the engine on / off request threshold value shown in FIG.

  Next, in step 214, it is determined whether an engine-on request is being made. The determination determines whether or not the engine on request based on the on / off request map in step 204 is being performed. If the determination is negative, the process returns to step 200 and the above processing is repeated. If the determination is affirmative, the routine proceeds to step 216.

  In step 216, the engine-on request is canceled, the process returns to step 200, and the above-described processing is repeated. That is, when there is residual heat in a state where cold air and warm air are mixed by the air mix damper, the engine-on request is prohibited.

  Here, the above-described engine on / off request control will be specifically described.

  When heating is instructed by the temperature setting device 58, for example, when the passenger compartment is cold as shown in FIG. 4, the calculated target outlet temperature (TAO) is 40 ° C. or higher, and the determination in step 202 is affirmed. The At the start of heating, the air mix damper opening SW is also 100%, the determination in step 208 is denied, and an engine on / off request based on the engine on / off request map is performed in step 204. That is, an engine on / off request is made based on a predetermined threshold value of the engine water temperature in accordance with the target outlet temperature (TAO).

  Subsequently, when the passenger compartment temperature rises, the air mix damper opening SW is adjusted and the opening degree of the air mix damper 36 is reduced as shown in FIG. This determination is affirmed. At this time, since the water temperature is sufficiently warm, the determination in step 212 is affirmed. If the engine-on request is made in step 204, the determination in step 216 is affirmed and the engine-on request is canceled. Thus, in the above-described automatic air conditioner control (FIG. 3), the vehicle interior temperature is controlled so as not to decrease. Therefore, the opening degree of the air mix damper 36 is controlled to return to 100%, and the target outlet temperature (TAO) is set. Controlled to maintain. In this embodiment, the air conditioner 36 is controlled to gradually return the opening degree of the air mix damper 36 to 100% by the automatic air conditioner control. However, when the engine-on request is canceled, the air mix damper 36 is forcibly controlled. The opening may be controlled to return to 100%.

  When the engine on / off request control is repeated in this manner, the engine water temperature gradually decreases as the engine is stopped, etc., and becomes a water temperature at which the target blowing temperature cannot be maintained, that is, a water temperature not higher than a predetermined water temperature. As a result, when step 212 is denied and the routine proceeds to step 204, an engine-on request is made. That is, an engine on request is made to the engine ECU 62 at a lower engine water temperature threshold than the engine on / off request map shown in FIG.

  Therefore, in the vehicle air conditioner 10 according to the present embodiment, when the engine-on request is made, the opening degree of the air mix damper 36 is less than 100%, that is, a state where cold air and hot air are mixed. In this case, the engine-on request is prohibited by canceling the engine-on request, and the opening degree of the air mix damper 36 is controlled to return to 100%, and the engine-on request is made to a predetermined water temperature at which the target outlet temperature (TAO) cannot be maintained. Therefore, it is possible to prevent the engine from being turned on even when there is enough residual heat of the water temperature, and to further improve fuel efficiency by extending the engine stop time compared to the conventional technology Can do.

  In the above embodiment, when an electric water pump is applied as a water pump for circulating engine cooling water and the temperature becomes lower than a predetermined water temperature in step 212, an operation request for the electric water pump is sent to the engine ECU 62. Then, the air conditioner ECU 46 may control the temperature of the water flowing through the heater core 38 by operating the electric water pump. This makes it possible to further increase the fuel consumption by further extending the stop time.

  In the above embodiment, the air conditioner ECU 46 makes an engine on / off request to the engine ECU 62 without particularly detecting the engine start state. However, the present invention is not limited to this. May detect the engine start state from the engine ECU 62 and make an engine on / off request in consideration of the engine start state. That is, the air conditioner ECU 46 makes an engine-on request when the engine water temperature is equal to or lower than a threshold (engine-on-request threshold) when the engine is stopped and the target blow-off temperature is predetermined. The engine-off request may be made when the water temperature that is predetermined according to the temperature is equal to or higher than a threshold value (engine-off request threshold value).

It is a block diagram which shows the structure of the vehicle air conditioner concerning embodiment of this invention. It is a graph which shows an example of the engine blow-off request map of target blowing temperature and water temperature. It is a flowchart which shows an example of the flow of the automatic air-conditioner control performed by air-conditioner ECU. The graph which shows the change with respect to time passage of the target blowing temperature (TAO), the heater blowing temperature, the water temperature (TWE), and the opening degree (SW) of the air mix damper 36 when driving arbitrarily while performing the automatic air conditioner control. is there. It is a flowchart which shows an example of the flow of the engine on-off request | requirement control performed by the air-conditioner ECU of the vehicle air conditioner concerning embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vehicle air conditioner 36 Air mix damper 38 Heater core 46 Air conditioner ECU
52 Outside air temperature sensor 54 Car interior temperature sensor 56 Solar radiation sensor 58 Temperature setting device 60 Temperature sensor after evaporator 62 Engine ECU

Claims (4)

The target blown air temperature for air-conditioning the passenger compartment is calculated, and the calculated target blown temperature is obtained according to the mixing state by the mixing means for mixing the cold air and the hot air using the heat of the engine cooling water. A vehicle air conditioner for air conditioning the interior of the vehicle,
Engine start requesting means for making an engine start request for maintaining the heating capacity when the temperature of the engine coolant predetermined according to the target blowing temperature is equal to or lower than a threshold;
Determining means for determining a mixed state of cold air and hot air by the mixing means;
An engine start prohibiting means for prohibiting the engine start request when the determining means determines that the cold air and the hot air are mixed by the mixing means;
A vehicle air conditioner comprising:   2. The apparatus according to claim 1, further comprising a setting unit that sets a temperature of engine cooling water for performing the engine start request to be lower than the threshold when the engine start request is prohibited by the engine start prohibiting unit. Vehicle air conditioner.   When the engine start request is prohibited by the engine start prohibiting means, the mixing state control for maintaining the target blowing temperature by controlling the mixing means so that the ratio of hot air is increased in the mixing state by the mixing means The vehicle air conditioner according to claim 1 or 2, further comprising means.   When the engine start request is prohibited by the engine prohibiting means, the apparatus further comprises a cooling water circulation control means for controlling the electric water pump capable of circulating the engine cooling water even when the engine is stopped to maintain the target blowing temperature. The vehicle air conditioner according to any one of claims 1 to 3.

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