Vehicle air-conditioning system

Abstract

To provide an air conditioning system for a vehicle capable of suppressing intrusion of rainwater into an outside air introduction port even when a weather condition and inclination of a vehicle body are changed while achieving high air conditioning efficiency.SOLUTION: The vehicular air-conditioning system 14 includes the inside-outside air switching door 25 configured to adjust the outside air mixed amount E from the outside air introduction port 19 and the inside air mixed amount G from the inside air introduction port 20, and the air-conditioning control unit 50 configured to control the inside-outside air switching door 25. The air-conditioning control unit 50 calculates the first inside air mixed amount G1 based on the air-conditioning load, and calculates the second inside air mixed amount G2 based on the vehicle body angle and the weather condition. The inside air mixing amount G by the inside / outside air switching door 25 is set based on a larger value of the first inside air mixing amount G1 and the second inside air mixing amount G2.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle air conditioning system for conditioning the interior of a vehicle. [Background technology]

[0002] Generally, a vehicle air conditioning system for conditioning the interior of a vehicle such as an automobile has an outside air inlet for introducing air from outside the vehicle and an inside air inlet for introducing air from inside the vehicle, both located upstream of an air conditioning duct of an air conditioner. The opening degrees of the outside air inlet and the inside air inlet are adjusted by an inside / outside air switching door. The opening degree of the inside / outside air switching door is controlled by an air conditioning control unit.

[0003] A cowl top cover is provided above the fresh air inlet of the air conditioner configured as described above. An fresh air inlet passage communicating with the fresh air inlet is formed below the cowl top cover. The cowl top cover also has a plurality of holes formed therein for introducing fresh air into the fresh air inlet passage.

[0004] When a vehicle is running in the rain, rainwater may enter the fresh air intake passage through the holes in the cowl top cover along with the fresh air. Various techniques have been proposed to prevent rainwater that has entered the fresh air intake passage from entering the fresh air inlet.

[0005] For example, Patent Document 1 (JP 2020-185888 A) discloses a vehicle air conditioning system that switches a portion of the amount of outside air introduced (amount of outside air mixed in) to inside air when the air volume exceeds a predetermined air volume compared to the requested air volume during rainy weather and the outside air introduction mode is requested. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-185888 Summary of the Invention [Problem to be solved by the invention]

[0007] However, because the technology disclosed in Patent Document 1 basically limits the amount of outside air mixed in during the outside air intake mode to prevent rainwater from entering, it can be difficult to sufficiently prevent rainwater from entering depending on the inclination of the vehicle body while the vehicle is running, for example. Also, if the amount of inside and outside air introduced is uniformly switched when the wind volume during rainy weather exceeds a predetermined level, as in the technology disclosed in Patent Document 1, there is a risk of inefficient air conditioning control.

[0008] The present invention has been made in consideration of the above circumstances, and aims to provide a vehicle air conditioning system that can achieve high air conditioning efficiency while suppressing the intrusion of rainwater into the outside air inlet even when weather conditions change and the inclination of the vehicle body changes. [Means for solving the problem]

[0009] A vehicle air conditioning system according to one aspect of the present invention comprises an inside / outside air switching door for adjusting the amount of outside air mixed in from the outside air inlet and the amount of inside air mixed in from the inside air inlet; a first inside air mixing amount calculation means for calculating a first inside air mixing amount to achieve high air conditioning efficiency based on the air conditioning load; a second inside air mixing amount calculation means for calculating a second inside air mixing amount to suppress water intrusion from the outside air inlet based on the vehicle body angle and weather conditions; and an inside air mixing amount setting means for setting the inside air mixing amount by the inside / outside air switching door based on the larger value of the first inside air mixing amount or the second inside air mixing amount. [Effects of the Invention]

[0010] According to the vehicle air conditioning system of the present invention, high air conditioning efficiency can be achieved while preventing rainwater from entering the outside air inlet even when weather conditions change and the inclination of the vehicle body changes. [Brief explanation of the drawings]

[0011] [Figure 1] A perspective view showing the front of the vehicle with the engine hood removed. [Figure 2] Schematic diagram of a vehicle air conditioning system [Figure 3] Map for calculating standard amount of air mixed in based on air volume [Figure 4] Map for calculating correction amount based on vehicle longitudinal angle [Figure 5] Map for calculating correction amount based on the vehicle's left and right angles [Figure 6] Map for calculating correction amount based on rainfall amount [Figure 7] Flowchart showing the control routine for the amount of internal air mixed in (part 1) [Figure 8] Flowchart showing the control routine for the amount of internal air mixed in (part 2) [Figure 9] Flowchart showing dehumidification capacity margin determination subroutine [Figure 10] Map for calculating the inside air intake opening based on the amount of inside air mixed in [Figure 11] 10 is a flowchart showing a part of a control routine for the amount of mixed internal air according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0013] In the drawings used in the following description, the scales of the components are different so that each component can be recognized easily. Therefore, the present invention is not limited to the number of components, the shapes of the components, the size ratios of the components, and the relative positions of the components shown in these drawings.

[0014] The configuration of the front part of a vehicle body equipped with a vehicle air conditioning system according to this embodiment will be described below. The vehicle according to this embodiment is a right-hand drive vehicle with the driver's seat on the right side.

[0015] As shown in FIG. 1, the front part of a vehicle body 2 of a vehicle 1 is configured to include a front windshield glass 3 (hereinafter referred to as windshield 3), a cowl top cover 4, and a dash upper panel 5.

[0016] The windshield 3 is provided in front of the front seats of the vehicle 1.

[0017] The cowl top cover 4 extends in the vehicle width direction at the lower end of the windshield 3 on the vehicle outer side.

[0018] These openings 6 are formed, for example, on the driver's seat side in the vehicle width direction. These openings 6 function as outside air inlets for introducing outside air.

[0019] As shown in Fig. 2, the dash upper panel 5 is disposed below the cowl top cover 4 in the engine compartment 9. The dash upper panel 5 has a downwardly concave shape. Due to this concave shape, the bottom 7 of the dash upper panel 5 is located at a distance from the cowl top cover 4. The dash upper panel 5 extends in the vehicle width direction, so that an outside air intake passage 8 is formed between the cowl top cover 4 and the dash upper panel 5.

[0020] The outside air introduction passage 8 is capable of guiding outside air introduced into the outside air introduction passage 8 through a plurality of openings 6 (see FIG. 1 ) to an outside air inlet 19 of a vehicle air conditioner 15 (hereinafter referred to as the air conditioner 15), which will be described later. Furthermore, the outside air introduction passage 8 is capable of guiding rainwater that drips from the plurality of openings 6 during rainy weather, for example, along a bottom 7 of the outside air introduction passage 8 in the vehicle width direction. Furthermore, the outside air introduction passage 8 is capable of guiding the rainwater guided along the bottom 7 to drain holes (not shown) provided on the outside in the vehicle width direction. As a result, the rainwater that has entered the outside air introduction passage 8 is discharged to the outside via the drain holes.

[0021] Further, at the front of the passenger compartment of the vehicle body 2, an air conditioning system 14 for a vehicle (hereinafter referred to as the air conditioning system 14) is disposed inside the instrument panel 10.

[0022] As shown in FIG. 2, the air conditioning system 14 includes an air conditioner 15 and an air conditioning control unit 50.

[0023] The air conditioner 15 is configured to include a blower / cooling unit 16 and a heater unit 17 .

[0024] The blower cooling unit 16 has a first air conditioning duct 18. An outside air inlet 19 and an inside air inlet 20 are provided upstream of the first air conditioning duct 18.

[0025] The outside air inlet 19 is connected to the outside air introduction passage 8 at a position spaced apart from the plurality of openings 6 of the cowl top cover 4. For example, if the plurality of openings 6 are provided on the right side in the vehicle width direction, the outside air inlet 19 is connected to the outside air introduction passage 8 on the left side in the vehicle width direction (see FIG. 1).

[0026] An inside / outside air switching door 25 is provided inside the first air conditioning duct 18. This inside / outside air switching door 25 is attached to the first air conditioning duct 18 at a branch point between the outside air inlet 19 and the inside air inlet 20 so as to be able to swing freely. That is, the inside / outside air switching door 25 is able to swing freely between a position where the opening degree of the inside air inlet 20 is "0%" and the opening degree of the outside air inlet 19 is "100%" to a position where the opening degree of the inside air inlet 20 is "100%" and the opening degree of the outside air inlet 19 is "0%."

[0027] The inside / outside air switching door 25 is driven by an inside / outside air switching actuator 26 (hereinafter referred to as the actuator 26).

[0028] By swinging the inside / outside air switching door 25 using this actuator 26, the inside / outside air switching door 25 can adjust the amount of outside air E mixed in from the outside air inlet 19 and the amount of inside air G mixed in from the inside air inlet 20.

[0029] A blower fan 27 is disposed downstream of the inside / outside air switching door 25, and blows the air introduced into the first air conditioning duct 18 into the vehicle cabin. Electrical components such as a blower motor 28 are connected to the blower fan 27.

[0030] Furthermore, an evaporator 29 is disposed downstream of the blower fan 27. The evaporator 29, together with a compressor 30, a condenser, a receiver tank, an expansion valve, and the like (all not shown), constitute a refrigeration cycle.

[0031] By means of these refrigeration cycles, the evaporator 29 is able to cool and dehumidify the air introduced by the blower fan 27.

[0032] The compressor 30 is connected to an engine output shaft (not shown) via an air conditioner clutch 31, which is an electromagnetic clutch or the like. Therefore, the air conditioner clutch 31 can switch the drive of the compressor 30 (switching between on and off) by connecting or disconnecting the compressor 30 to the engine output shaft.

[0033] The heater unit 17 has a second air conditioning duct 21. The second air conditioning duct 21 is connected to the downstream side of the first air conditioning duct 18. A heater core 47 is disposed inside the second air conditioning duct 21. This heater core 47 uses engine coolant after warming up to heat the intake air that has passed through the evaporator 29.

[0034] The heater core 47 is disposed, for example, obliquely with respect to the direction of airflow in the second air-conditioning duct 21. Furthermore, the heater core 47 is provided with an air mix door 48 that is swingable.

[0035] The air mix door 48 is driven by an opening adjustment actuator 49 (hereinafter referred to as the actuator 49). Therefore, the actuator 49 can adjust the amount of intake air passing through the heater core 47 by swinging the air mix door 48.

[0036] On the downstream side of the heater core 47, the second air conditioning duct 21 is provided with a defroster outlet 35, a ventilation outlet 36, and a heater outlet 37.

[0037] The defroster outlet 35 is connected to a defroster duct 40. Furthermore, the downstream side of the defroster duct 40 has a plurality of openings that blow out conditioned air onto the surface of the windshield 3 facing the interior of the vehicle.

[0038] The ventilation outlet 36 is connected to a ventilation duct 41 disposed in the instrument panel 10 .

[0039] The heater outlet 37 is in communication with a heater duct 42 .

[0040] Further, the second air-conditioning duct 21 is provided with a defroster door 43, a ventilation door 44, and a heater door 45 for opening and closing the respective air outlets 35, 36, and 37.

[0041] Door switching actuators 46a to 46c (hereinafter referred to as actuators 46a to 46c) open and close the doors 43, 44, and 45. By opening and closing the doors 43, 44, and 45, the actuators 46a to 46c can adjust the proportion of conditioned air blown into the vehicle interior from the air outlets 35, 36, and 37.

[0042] The blower motor 28, air conditioner clutch 31, and actuators 26, 46a to 46c, and 49 of the air conditioner 15 configured as above are controlled by an air conditioning control unit 50 serving as a control unit, as shown in FIG.

[0043] The air conditioning control unit 50 is composed of a well-known microcomputer equipped with a CPU, RAM, ROM, non-volatile storage, etc., and its peripheral devices. The ROM, which serves as a non-transitory tangible recording medium, stores programs to be executed by the CPU and fixed data such as data tables in advance. Note that all or part of the processor's functions may be configured using logic circuits or analog circuits. Furthermore, the processing of various programs may be realized by electronic circuits such as FPGAs.

[0044] The input side of this air conditioning control unit 50 is connected to, for example, an operation panel 52, an inside air temperature sensor 53, an outside air temperature sensor 54, a solar radiation sensor 55, a water temperature sensor 56, a vehicle body angle sensor 57, a raindrop sensor 58, a humidity sensor 59, and an evaporator temperature sensor 60.

[0045] The operation panel 52 is disposed on the instrument panel 10 at the front of the vehicle interior. The operation panel 52 is provided with, for example, an air conditioning system switch, an automatic operation mode switch, an inside / outside air selector switch, a temperature setting switch, and a defroster switch.

[0046] The air conditioning system switch is for turning the air conditioning system 14 on and off.

[0047] The automatic operation mode switch is used to switch the automatic operation mode of the air conditioner 15 on and off.

[0048] The inside / outside air changeover switch is operated by a passenger to switch between an outside air introduction mode and an inside air circulation mode of the air conditioner 15.

[0049] The temperature setting switch is operated by the occupant to set the set temperature Tset in the vehicle interior.

[0050] The defroster switch is used, for example, by a driver to switch on and off a defroster for clearing the windshield 3 from fogging.

[0051] The following description will exemplify air conditioning control when the automatic operation mode is set to ON.

[0052] The inside air temperature sensor 53 is provided, for example, in the vehicle interior, below the instrument panel 10. This inside air temperature sensor 53 detects the temperature Tin inside the vehicle interior. On the other hand, the outside air temperature sensor 54 is provided, for example, in the inside lower part of the front bumper. This outside air temperature sensor 54 detects the temperature Tout outside the vehicle interior.

[0053] The solar radiation sensor 55 is provided, for example, on the upper part of the instrument panel 10. This solar radiation sensor detects the amount of solar radiation entering the vehicle interior through the windshield 3 or the like.

[0054] The water temperature sensor 56 is provided, for example, in the cylinder block of the engine and detects the temperature of the cooling water flowing through a water jacket formed in the cylinder block.

[0055] The body angle sensor 57 is configured by, for example, a gyro sensor. This body angle sensor 57, as body angle detection means, detects, for example, the pitch angle and roll angle of the body 2. Thus, in this embodiment, the body angle sensor 57 corresponds to a specific example of body angle detection means.

[0056] The raindrop sensor 58 is installed, for example, near the windshield 3. The raindrop sensor 58 detects rainfall and further detects the amount of rainfall when it rains. Thus, in this embodiment, the raindrop sensor 58 corresponds to a specific example of rainfall amount detection means.

[0057] The humidity sensor 59 is provided, for example, integrally with the interior air temperature sensor 53, at the bottom of the instrument panel 10. This humidity sensor 59 detects the relative humidity inside the vehicle cabin. The humidity sensor 59 also functions as a window fogging detection means. In this way, in this embodiment, the humidity sensor 59 corresponds to a specific example of a relative humidity detection means.

[0058] The evaporator temperature sensor 60 is provided, for example, on the outer surface of the refrigerant pipe of the evaporator 29. The evaporator temperature sensor 60 detects the evaporator temperature.

[0059] The air conditioning control unit 50 performs various controls on the blower motor 28, the air conditioning clutch 31, the actuators 26, 46a to 46c, 49, etc., based on input signals from these switches and sensors and by referring to a preset map or the like.

[0060] The following mainly describes the control of the inside / outside air switching door 25, which is performed using the actuator 26. In controlling the inside / outside air switching door 25, the air conditioning control unit 50 calculates the amount G of mixed inside air.

[0061] When calculating the amount of mixed internal air G, the air conditioning control unit 50 calculates, for example, a first mixed internal air amount G1, a second mixed internal air amount G2, and a third mixed internal air amount G3.

[0062] The first internal air mixing amount G1 is calculated based on input signals from, for example, the operation panel 52, the internal air temperature sensor 53, the external air temperature sensor 54, the solar radiation sensor 55, and the water temperature sensor 56. This first internal air mixing amount G1 is calculated as the optimal internal air mixing amount for increasing air conditioning efficiency based on the air conditioning load during heating / cooling operation of the air conditioner 15.

[0063] When calculating the first internal air mixture amount G1, for example, the air conditioning control unit 50 calculates a target blowing temperature with respect to the set temperature Tset based on the in-vehicle temperature Tin, the outside air temperature Tout, and the solar radiation amount. Then, the air conditioning control unit 50 calculates the first internal air mixture amount G1 as the internal air mixture amount for efficiently adjusting the blowing temperature to the target blowing temperature.

[0064] Here, for example, in the cooling operation, when the outside air temperature Tout and the in-vehicle temperature Tin are higher than the target blowing temperature, and the outside air temperature Tout is higher than the in-vehicle temperature Tin (Tout>Tin), the outside air load becomes higher than the internal air load. In such a case, it can be expected to reduce the air conditioning load and improve the air conditioning efficiency by setting the internal air mixture amount relatively more than the outside air mixture amount. Conversely, in the cooling operation, when the outside air temperature Tout and the in-vehicle temperature Tin are higher than the target blowing temperature, and the outside air temperature Tout is lower than the in-vehicle temperature Tin (Tout<Tin), the internal air load becomes higher than the outside air load. In such a case, it can be expected to reduce the air conditioning load and improve the air conditioning efficiency by setting the internal air mixture amount relatively less than the outside air mixture amount. In addition, various conditions are assumed to reduce the air conditioning load and improve the air conditioning efficiency. The air conditioning control unit 50 stores a map or the like preset based on various conditions. By referring to such a map or the like, the air conditioning control unit 50 sets the first internal air mixture amount G1 as the internal air mixture amount for reducing the air conditioning load and improving the air conditioning efficiency.

[0065] Thus, in the present embodiment, the air conditioning control unit 50 corresponds to a specific example of the first internal air mixture amount calculating means.

[0066] The second mixed air amount G2 is calculated based on, for example, a control signal for the blower motor 28 and input signals from the vehicle body angle sensor 57 and the raindrop sensor 58. That is, the second mixed air amount G2 is calculated as the minimum amount of mixed air necessary to suppress water intrusion through the outside air inlet 19, based on the airflow rate of the blower fan 27, the body angle of the vehicle body 2, and weather conditions. For example, if it is estimated based on the amount of rainfall and the body angle that there is a high possibility of water intrusion through the outside air inlet 19, it is necessary to suppress the amount of mixed outside air to suppress the water intrusion. Here, for example, when the airflow rate of the blower fan 27 is constant, there is a trade-off between the amount of mixed outside air and the amount of mixed inside air. Therefore, in such a case, the air conditioning control unit 50 sets the second mixed air amount G2 higher than when the possibility of water intrusion is low.

[0067] More specifically, the second internal air mixing amount G2 is calculated based on, for example, the standard internal air mixing amount S, a correction amount A based on the vehicle body's longitudinal angle, a correction amount B based on the vehicle body's lateral angle, and a correction amount C based on the amount of rainfall.

[0068] The reference internal air amount S is calculated based on the airflow rate of the blower fan 27, for example, by referring to a calculation map for the reference internal air amount shown in Fig. 3. The calculation map for the reference internal air amount is a map for controlling the amount of outside air mixed in to a predetermined amount or less. In the example shown in Fig. 3, the reference internal air amount S calculated by the calculation map for the reference internal air amount increases stepwise within a range of s1 to s5 as the airflow rate of the blower fan 27 increases.

[0069] The correction amount A based on the vehicle body longitudinal angle is calculated based on the vehicle body longitudinal angle, for example, by referring to a correction amount calculation map shown in Fig. 4. The correction amount A based on the vehicle body longitudinal angle is a correction amount for correcting the reference internal air mixing amount S to the increasing side as the outside air introduction port 19 is tilted in a direction that makes it easier for water to enter due to the tilt of the vehicle body 2 in the longitudinal direction. Here, the outside air introduction port 19 in this embodiment opens toward the front of the vehicle body 2. Therefore, as shown in Fig. 4, the correction amount A calculated by this correction amount calculation map increases in stages within a range of 0 to a2 as the front of the vehicle body 2 is tilted upward, for example.

[0070] 4, the correction amount A calculated by this correction amount calculation map is a correction amount for correcting the reference mixed air amount S to the decreasing side as the front part of the vehicle body 2 tilts downward. Therefore, the correction amount A calculated by this correction amount calculation map becomes smaller in stages within a range of 0 to -a2 as the front part of the vehicle body 2 tilts downward, for example.

[0071] The correction amount B based on the vehicle body left-right angle is calculated based on the vehicle body left-right angle, for example, by referring to a correction amount calculation map shown in Fig. 5. The correction amount B based on the vehicle body left-right angle is a correction amount for correcting the reference internal air mixing amount S to the increasing side as the outside air introduction port 19 is tilted in a direction that makes it easier for water to enter due to the left-right tilt of the vehicle body 2. Here, the outside air introduction port 19 in this embodiment is provided on the left side (passenger seat side) of the vehicle body 2. Therefore, as shown in Fig. 5, the correction amount B calculated by this correction amount calculation map becomes larger in stages within a range of 0 to b2 as the left side of the vehicle body 2 is tilted downward, for example.

[0072] 5, the correction amount B calculated by this correction amount calculation map is a correction amount for correcting the reference mixed air amount S to the decreasing side as the left part of the vehicle body 2 tilts upward. Therefore, the correction amount B calculated by this correction amount calculation map becomes smaller in stages within a range of 0 to -b2 as the left part of the vehicle body 2 tilts upward, for example.

[0073] The rainfall-based correction amount C is calculated based on the amount of rainfall, for example, by referring to a correction amount calculation map shown in Fig. 6. The rainfall-based correction amount C is a correction amount for correcting the reference internal air amount S to the increasing side as the amount of rainfall increases. Therefore, as shown in Fig. 6, the correction amount C calculated by this correction amount calculation map increases in stages within a range of 0 to c4 as the amount of rainfall increases, for example.

[0074] Based on these calculation maps, the air conditioning control unit 50 calculates the second mixed inside air amount G2 using the following equation (1).

[0075] G2=S+A+B+C (1)

[0076] The second mixed inside air amount G2 can be corrected using an average value of the second mixed inside air amount G2 calculated in the past. For example, the air conditioning control unit 50 calculates an average value for a predetermined number of cycles from a plurality of second mixed inside air amounts G2 calculated continuously at set time intervals. The air conditioning control unit 50 then compares the past average value with the latest average value, and if the past average value is smaller, sets the latest average value as the final second mixed inside air amount G2.

[0077] On the other hand, when the state in which the past average value is larger than the latest average value continues for a set time, the air conditioning control unit 50 replaces the second amount of mixed inside air G2 with the latest average value. Note that when the state in which the past average value of the second amount of mixed inside air G2 is larger than the latest average value does not continue for the set time, the air conditioning control unit 50 maintains the past average value of the second amount of mixed inside air G2.

[0078] As a result, if the past average value of the second mixed inside air amount G2 is smaller than the latest average value, the air conditioning control unit 50 immediately adopts the latest average value as the final second mixed inside air amount G2. On the other hand, if the past average value is larger than the latest average value, the air conditioning control unit 50 replaces the final second mixed inside air amount G2 with the latest average value after this state continues for a set time.

[0079] 3, 4, 5, and 6 are obtained in advance by experiments or the like for each vehicle model or each specification of the air conditioning system 14. In each calculation map, the values ​​to be determined are slightly different when increasing and when decreasing because hysteresis is provided to prevent hunting of the operation.

[0080] Thus, in this embodiment, the air conditioning control unit 50 corresponds to a specific example of a second mixed inside air amount calculation means.

[0081] The third amount of mixed inside air G3 is calculated, for example, based on an input signal from the humidity sensor 59. As the third amount of mixed inside air G3, a maximum value of the amount of mixed inside air that is allowable for suppressing window fogging is calculated based on relative humidity information.

[0082] For example, based on the relative humidity information in the vehicle cabin, the air conditioning control unit 50 estimates the dew point temperature near the windshield 3 using a preset map or the like. Then, the air conditioning control unit 50 estimates the state of window fogging on the windshield 3 from the temperature in the vehicle cabin. Here, for example, if it is estimated that the possibility of window fogging is high, it is necessary to reduce the amount of internal air mixed in and increase the amount of external air mixed in to suppress window fogging. Therefore, in such a case, the air conditioning control unit 50 sets the third internal air mixing amount G3 low to increase the amount of external air mixed in and improve the effect of suppressing window fogging.

[0083] Thus, in this embodiment, the air conditioning control unit 50 corresponds to a specific example of a third mixed inside air amount calculation means.

[0084] In principle, the air conditioning control unit 50 sets the larger of the first mixed internal air amount G1 and the second mixed internal air amount G2 as the final mixed internal air amount G. However, to prevent window fogging, the value of the final mixed internal air amount G is limited to be equal to or less than the third mixed internal air amount G3. In addition, if the defroster outlet 35 is included as an outlet for conditioned air, the air conditioning control unit 50 sets the final mixed internal air amount G to "0." Furthermore, immediately after the ignition switch has transitioned from on to off, the air conditioning control unit 50 sets the final mixed internal air amount G to "0" or a value equivalent to the total air volume of the first air conditioning duct 18.

[0085] Then, the air conditioning control unit 50 controls the actuator 26 based on the final amount G of mixed inside air, and controls the opening degree of the inside / outside air switching door 25.

[0086] Thus, in this embodiment, the air conditioning control unit 50 corresponds to a specific example of an inside air mixing amount setting unit.

[0087] Next, the control of the amount of mixed inside air by the air conditioning control unit 50 of this embodiment will be described with reference to the flowchart of the control routine for the amount of mixed inside air shown in FIGS.

[0088] This routine is repeatedly executed by the air conditioning control unit 50 at set intervals.

[0089] As shown in FIG. 7, when the routine starts, first, in step S101, the air conditioning control unit 50 calculates the first to third mixed inside air amounts G1, G2, G3.

[0090] In the following step S102, the air conditioning control unit 50 determines whether the third mixed inside air amount G3 is greater than the first mixed inside air amount G1.

[0091] In step S102, if the air conditioning control unit 50 determines that the third mixed inside air amount G3 is equal to or less than the first mixed inside air amount G1 (step S102: NO), the process proceeds to step S106, which will be described later.

[0092] On the other hand, in step S102, when the air conditioning control unit 50 determines that the third mixed inside air amount G3 is greater than the first mixed inside air amount G1 (step S102: YES), the process proceeds to step S103.

[0093] When the process proceeds from step S102 to step S103, the air conditioning control unit 50 determines whether the second amount of mixed inside air G2 is greater than the first amount of mixed inside air G1.

[0094] In step S103, if the air conditioning control unit 50 determines that the second mixed inside air amount G2 is equal to or less than the first mixed inside air amount G1 (step S103: NO), the process proceeds to step S104. That is, if the first mixed inside air amount G1 is smaller than the third mixed inside air amount G3 and equal to or greater than the second mixed inside air amount G2 (G3>G1≧G2), the air conditioning control unit 50 proceeds to step S104.

[0095] Then, in step S104, the air conditioning control unit 50 sets the first amount of mixed inside air G1 as the final amount of mixed inside air G. After that, the air conditioning control unit 50 proceeds to step S113, which will be described later.

[0096] On the other hand, in step S103, when the air conditioning control unit 50 determines that the second mixed inside air amount G2 is greater than the first mixed inside air amount G1 (step S103: YES), the process proceeds to step S105.

[0097] When the process proceeds from step S103 to step S105, the air conditioning control unit 50 determines whether the second amount of mixed inside air G2 is greater than the third amount of mixed inside air G3.

[0098] In step S105, if the air conditioning control unit 50 determines that the second mixed inside air amount G2 is equal to or less than the third mixed inside air amount G3 (step S105: NO), the process proceeds to step S110. That is, if the second mixed inside air amount G2 is equal to or less than the third mixed inside air amount G3 and is greater than the first mixed inside air amount G1 (G3≧G2>G1), the air conditioning control unit 50 proceeds to step S110, which will be described later.

[0099] On the other hand, in step S105, if the air conditioning control unit 50 determines that the second mixed inside air amount G2 is greater than the third mixed inside air amount G3 (step S105: YES), the process proceeds to step S107. That is, if the third mixed inside air amount G3 is smaller than the second mixed inside air amount G2 and greater than the first mixed inside air amount G1 (G2>G3>G1), the air conditioning control unit 50 proceeds to step S107, which will be described later.

[0100] Furthermore, when the process proceeds from step S102 to step S106, the air conditioning control unit 50 determines whether the second amount of mixed inside air G2 is greater than the third amount of mixed inside air G3.

[0101] In step S106, if the air conditioning control unit 50 determines that the second mixed inside air amount G2 is equal to or less than the third mixed inside air amount G3 (step S106: NO), the process proceeds to step S112. That is, if the third mixed inside air amount G3 is equal to or less than the first mixed inside air amount G1 and equal to or greater than the second mixed inside air amount G2 (G1≧G3≧G2), the air conditioning control unit 50 proceeds to step S112, which will be described later.

[0102] On the other hand, in step S106, if the air conditioning control unit 50 determines that the second mixed inside air amount G2 is greater than the third mixed inside air amount G3 (step S106: YES), the process proceeds to step S107. That is, if the third mixed inside air amount G3 is smaller than the second mixed inside air amount G2 and is equal to or less than the first mixed inside air amount G1 (G2>G3≦G1), the air conditioning control unit 50 proceeds to step S107.

[0103] When the process proceeds from step S105 or step S106 to step S107, the air conditioning control unit 50 determines whether there is a margin in the dehumidifying capacity of the air conditioner 15. That is, when the second mixed inside air amount G2 is greater than the third mixed inside air amount G3, the air conditioning control unit 50 performs a dehumidifying capacity margin determination. This determination is performed, for example, based on a dehumidifying capacity margin determination subroutine shown in FIG. 9.

[0104] When the subroutine starts, the air conditioning control unit 50 determines, for example, in step S201, whether the driving force of the compressor system is equal to or less than a predetermined upper limit value D of driving force that has been set in advance.

[0105] In step S201, if the air conditioning control unit 50 determines that the driving force is greater than the driving force upper limit value D (step S201: NO), the process proceeds to step S205.

[0106] On the other hand, in step S201, if the air conditioning control unit 50 determines that the driving force is equal to or less than the driving force upper limit value D (step S201: YES), the process proceeds to step S202.

[0107] In step S202, the air conditioning control unit 50 determines, for example, whether the temperature of the evaporator 29 (evaporator temperature) is equal to or higher than a preset threshold temperature Tth. Here, the threshold temperature Tth is a value obtained by adding a predetermined margin (for example, 5°C) to the lower limit value (for example, 0°C) of the temperature of the evaporator 29 determined based on the capacity of the compressor 30, etc.

[0108] Then, in step S202, if the air conditioning control unit 50 determines that the temperature is lower than the threshold temperature Tth (step S202: NO), the process proceeds to step S205.

[0109] On the other hand, in step S202, if the air conditioning control unit 50 determines that the temperature is equal to or higher than the threshold temperature Tth (step S202: YES), the process proceeds to step S203.

[0110] In step S203, the air conditioning control unit 50 determines whether the difference in capacity between the upper limit capacity of the compressor 30 and the latest capacity is equal to or greater than ΔR, for example.

[0111] Then, in step S203, if the air conditioning control unit 50 determines that the capacity difference ΔR between the upper limit capacity and the latest capacity is smaller than the capacity difference ΔR (step S203: NO), the process proceeds to step S205.

[0112] On the other hand, if the air conditioning control unit 50 determines in step S203 that the capacity difference ΔR between the upper limit capacity and the latest capacity is equal to or greater than that (step S203: YES), it proceeds to step S204 and determines that there is sufficient dehumidification capacity.

[0113] Then, in step S204, the air conditioning control unit 50 determines that there is a margin in the dehumidifying capacity, and then exits the subroutine.

[0114] When the process proceeds from step S201, S202, or S203 to step S205, the air conditioning control unit 50 determines that there is no room for dehumidification, and then exits the subroutine.

[0115] In the main routine of FIG. 7, when the process moves from step S107 to step S108, the air conditioning control unit 50 determines whether there is a margin in the dehumidification capacity.

[0116] In step S108, if the air conditioning control unit 50 determines that there is no margin in the dehumidification capacity (step S108: NO), the process proceeds to step S111.

[0117] On the other hand, in step S108, if the air conditioning control unit 50 determines that there is a margin in the dehumidification capacity (step S108: YES), the process proceeds to step S109.

[0118] When the process proceeds from step S108 to step S109, the air conditioning control unit 50 increases the dehumidifying efficiency of the air conditioner 15, and then proceeds to step S110. Here, for example, the air conditioning control unit 50 increases the cooling capacity of the evaporator 29 by controlling the compressor 30, etc. This increases the dehumidifying efficiency of the air conditioner 15. Therefore, the air conditioning control unit 50 can suppress fogging of the windshield 3 even when a high amount of inside air is maintained.

[0119] When the process proceeds from step S105 or step S109 to step S110, the air conditioning control unit 50 sets the second amount of mixed inside air G2 as the final amount of mixed inside air G. Thereafter, the air conditioning control unit 50 proceeds to step S113, which will be described later.

[0120] When the process moves from step S108 to step S111, the air conditioning control unit 50 reduces the air volume in the first air conditioning duct 18 to a predetermined air volume by controlling the drive of the blower fan 27, and then moves to step S112. This allows the air conditioning control unit 50 to prevent rainwater from entering even when the amount of inside air mixed in is set lower than expected, prioritizing the prevention of window fogging. Furthermore, by reducing the air volume in the first air conditioning duct 18 to the predetermined air volume, the air conditioning control unit 50 makes it possible to reduce the amount of inside air mixed in without increasing the amount of outside air mixed in.

[0121] When the process proceeds from step S106 or step S111 to step S112, the air conditioning control unit 50 sets the third amount of mixed inside air G3 as the final amount of mixed inside air G. After that, the air conditioning control unit 50 proceeds to step S113.

[0122] When the process proceeds from step S104, step S110, or step S112 to step S113 (see FIG. 8), the air conditioning control unit 50 determines whether the defroster outlet 35 is included as an outlet for conditioned air.

[0123] In step S113, if it is determined that the defroster outlet 35 is not included as an outlet for conditioned air (step S113: NO), the air conditioning control unit 50 proceeds to step S115 while maintaining the set amount of inside air mixed in G.

[0124] On the other hand, in step S113, if the air conditioning control unit 50 determines that the defroster outlet 35 is included as an outlet for conditioned air (step S113: YES), the process proceeds to step S114.

[0125] When the process proceeds from step S113 to step S114, the air conditioning control unit 50 sets the amount of mixed inside air G to "0." That is, when the air conditioning control unit 50 determines that the defroster outlet 35 is included as an outlet for conditioned air, it replaces the final amount of mixed inside air G with "0." After that, the air conditioning control unit 50 proceeds to step S115.

[0126] When the process proceeds from step S113 or step S114 to step S115, the air conditioning control unit 50 determines whether or not the ignition switch has just been switched from on to off.

[0127] In step S115, if the air conditioning control unit 50 determines that the ignition switch has not transitioned from on to off (step S115: NO), the process proceeds to step S116.

[0128] In step S116, the air conditioning control unit 50 calculates the inside air inlet opening F (hereinafter referred to as opening F) based on the final amount of mixed inside air G. This opening F is calculated, for example, using a preset calculation map (see FIG. 10). Note that this calculation map is obtained in advance by experiments or the like, for example, for each vehicle model or each specification of the air conditioning system 14. Also, in the present embodiment, an example has been described in which the opening F is calculated using the calculation map, but it may also be calculated using a mathematical formula.

[0129] Then, in the following step S117, the air conditioning control unit 50 controls the opening degree of the inside / outside air switching door 25 based on the opening degree F, and then exits the routine.

[0130] The opening degree F is an example of an index for controlling the driving of the inside / outside air switching door 25, and is not limited to the opening degree, and may be another index.

[0131] On the other hand, in step S115, if the air conditioning control unit 50 determines that the ignition switch has just transitioned from on to off (step S115: YES), the process proceeds to step S118.

[0132] When the process proceeds from step S115 to step S118, the air conditioning control unit 50 determines whether the second amount of mixed inside air G2 is greater than the reference amount of mixed inside air S or not.

[0133] In step S118, if the air conditioning control unit 50 determines that the second mixed inside air amount G2 is equal to or less than the reference mixed inside air amount S (step S118: NO), the process proceeds to step S119.

[0134] When the process proceeds from step S118 to step S119, the air conditioning control unit 50 sets the amount of mixed inside air G to "0." That is, if it is determined that the ignition switch has just transitioned from on to off and if it is determined that the second amount of mixed inside air G2 is equal to or less than the reference amount of mixed inside air S, the air conditioning control unit 50 replaces the final amount of mixed inside air G with "0." Thereafter, the air conditioning control unit 50 proceeds to step S121, which will be described later.

[0135] On the other hand, in step S118, if the air conditioning control unit 50 determines that the second mixed inside air amount G2 is greater than the reference mixed inside air amount S (step S118: YES), the process proceeds to step S120.

[0136] When the process proceeds from step S118 to step S120, the air conditioning control unit 50 sets the amount of mixed inside air G to a value equivalent to the total air volume in the first air conditioning duct 18, i.e., 100% inside air. In other words, if it is determined that the ignition switch has just transitioned from on to off and if it is determined that the second amount of mixed inside air G2 is greater than the reference amount of mixed inside air S, the air conditioning control unit 50 replaces the final amount of mixed inside air G with the total air volume in the first air conditioning duct 18. The air conditioning control unit 50 then proceeds to step S121.

[0137] When the process proceeds from step S119 or step S120 to step S121, the air conditioning control unit 50 calculates the opening degree F based on the final amount of mixed inside air G in the same manner as described above.

[0138] Then, in the following step S122, the air conditioning control unit 50 controls the opening degree of the inside / outside air switching door 25 based on the opening degree F, and then ends this routine.

[0139] According to this embodiment, the air conditioning system 14 includes an inside / outside air switching door 25 for adjusting the amount of outside air E mixed in from the outside air inlet 19 and the amount of inside air G mixed in from the inside air inlet 20, and an air conditioning control unit 50 for controlling the inside / outside air switching door 25. The air conditioning control unit 50 calculates a first inside air mixing amount G1 to achieve high air conditioning efficiency based on the air conditioning load, calculates a second inside air mixing amount G2 to suppress water intrusion from the outside air inlet 19 based on the vehicle body angle and weather conditions, and sets the inside air mixing amount G by the inside / outside air switching door 25 based on the larger value of the first inside air mixing amount G1 or the second inside air mixing amount G2.

[0140] As a result, the air conditioning system 14 can suppress the intrusion of rainwater into the outside air inlet 19 even when the weather conditions change and the inclination of the vehicle body 2 changes, while achieving high air conditioning efficiency.

[0141] That is, the air conditioning system 14 calculates the first mixed internal air amount G1 and the second mixed internal air amount G2 using the air conditioning control unit 50, and sets the mixed internal air amount G through the internal / external air switching door 25 based on the larger of the two values. This allows the air conditioning system 14 to always set the mixed internal air amount G that satisfies the requirements for the second mixed internal air amount G2. Therefore, the air conditioning system 14 can suppress water from entering through the external air inlet 19. Furthermore, when the first mixed internal air amount G1 is larger than the second mixed internal air amount G2, the air conditioning system 14 sets the mixed internal air amount G through the internal / external air switching door 25 based on the first mixed internal air amount G1. Therefore, the air conditioning system 14 can increase air conditioning efficiency while suppressing water from entering through the external air inlet 19.

[0142] Additionally, in this embodiment, the air conditioning control unit 50 calculates a third amount of mixed internal air G3 for suppressing fogging of the windshield 3. In principle, the air conditioning control unit 50 sets the amount of mixed internal air G so that it does not exceed the third amount of mixed internal air G3. This makes it possible to suppress fogging of the windshield 3.

[0143] In this case, when the second mixed internal air amount G2 is greater than the third mixed internal air amount G3 and there is a margin in the dehumidification capacity, the air conditioning control unit 50 exceptionally sets the mixed internal air amount G based on the second mixed internal air amount G2 in a state where the dehumidification capacity is increased. Therefore, the air conditioning system 14 can simultaneously suppress fogging of the windshield 3 and suppress water intrusion through the outside air inlet 19.

[0144] On the other hand, when the second mixed internal air amount G2 is greater than the third mixed internal air amount G3 and there is no margin for error in the dehumidification capacity, the air conditioning control unit 50 sets the mixed internal air amount G based on the third mixed internal air amount G3 while reducing the airflow rate of the blower fan 27. This allows the air conditioning control unit 50 to effectively suppress an increase in the amount of mixed external air, even when the mixed internal air amount G is set to a value smaller than the second mixed internal air amount G2 based on the third mixed internal air amount G3. Therefore, the air conditioning system 14 can simultaneously suppress fogging of the windshield 3 and the intrusion of water through the external air inlet 19, even when there is no margin for error in the dehumidification capacity.

[0145] Furthermore, when calculating the second mixed air amount G2, the air conditioning control unit 50 corrects the second mixed air amount G2 using an average value of previously calculated second mixed air amounts G2. For example, when the average value of the second mixed air amount G2 over multiple cycles is smaller than the latest average value, the air conditioning control unit 50 immediately adopts the latest average value as the final second mixed air amount G2. On the other hand, when the previous average value is larger than the latest average value, the air conditioning control unit 50 replaces the final second mixed air amount G2 with the latest average value after this state continues for a set time. By calculating the second mixed air amount G2 in this manner, the air conditioning control unit 50 can suppress hunting in the switching operation of the inside / outside air switching door 25. Therefore, the air conditioning system 14 can suppress unnecessary switching operation of the inside / outside air switching door 25, thereby improving the durability of the actuator 26.

[0146] Furthermore, after setting the final amount of mixed internal air G, if it is determined that the defroster outlet 35 is included as an outlet for conditioned air, the air conditioning control unit 50 replaces the final amount of mixed internal air G with "0." This allows the air conditioning system 14 to prioritize defogging of windows, thereby maintaining good visibility for occupants.

[0147] Furthermore, after setting the final mixed air amount G, if the air conditioning control unit 50 determines that the ignition switch has just transitioned from on to off and that the second mixed air amount G2 is greater than the reference mixed air amount S, the air conditioning control unit 50 sets the final mixed air amount G to a value equivalent to the total air volume in the first air conditioning duct 18, i.e., 100% inside air. This allows the air conditioning system 14 to accurately suppress water intrusion through the outside air inlet 19 even when the vehicle 1 is parked or stopped in a state where there is a high possibility of rainwater intrusion through the outside air inlet 19. On the other hand, if the air conditioning control unit 50 determines that the ignition switch has just transitioned from on to off and that the second mixed air amount G2 is equal to or less than the reference mixed air amount S, the air conditioning control unit 50 sets the final mixed air amount G to "0." This allows the air conditioning system 14 to achieve high interior ventilation performance when the ignition switch is turned on again.

[0148] This type of air conditioning control can be applied to various vehicle models with different shapes of cowl top cover 4. Therefore, the air conditioning system 14 can suppress water intrusion through the outside air inlet 19 without changing the shape of the cowl top cover 4.

[0149] Next, a modified example of the control of the amount of mixed inside air by the air conditioning control unit 50 of this embodiment will be described. In this modified example, instead of the processing from step S101 to step S112 described above, the processing from step S301 to step S304 shown in Fig. 11 is performed. The processing according to this modified example can be applied to the control of the air conditioning system 14 that does not have a humidity sensor 59, for example.

[0150] As shown in FIG. 11, when the routine starts, first, in step S301, the air conditioning control unit 50 calculates the first and second mixed inside air amounts G1 and G2.

[0151] In the following step S302, the air conditioning control unit 50 determines whether the second amount of mixed inside air G2 is greater than the first amount of mixed inside air G1.

[0152] In step S302, if the air conditioning control unit 50 determines that the second mixed inside air amount G2 is greater than the first mixed inside air amount G1 (step S302: YES), the process proceeds to step S303.

[0153] When the process proceeds from step S302 to step S303, the air conditioning control unit 50 sets the second amount of mixed inside air G2 as the final amount of mixed inside air G. After that, the air conditioning control unit 50 proceeds to step S113 (see FIG. 8).

[0154] On the other hand, in step S302, if the air conditioning control unit 50 determines that the second mixed inside air amount G2 is equal to or less than the first mixed inside air amount G1 (step S302: NO), the process proceeds to step S304.

[0155] When the process proceeds from step S302 to step S304, the air conditioning control unit 50 sets the first amount of mixed inside air G1 as the final amount of mixed inside air G. After that, the air conditioning control unit 50 proceeds to step S113 (see FIG. 8).

[0156] The processing from step S113 onwards is the same as in the previous embodiment, and therefore a description thereof will be omitted.

[0157] According to this embodiment, the air conditioning system 14 can achieve high air conditioning efficiency even in vehicle models that do not have a humidity sensor 59, and can also prevent rainwater from entering the outside air inlet 19 even when the inclination of the vehicle body 2 changes.

[0158] Although the air conditioning system 14 in this embodiment is described as being installed in a right-hand drive vehicle with the driver's seat on the right side, it can also be applied to a left-hand drive vehicle with the driver's seat on the left side.

[0159] The invention described in the above embodiments is not limited to these embodiments, and various modifications can be made in the implementation stage without departing from the gist of the invention. Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriate combinations of the disclosed multiple constituent elements.

[0160] Furthermore, even if some of the constituent elements are deleted from all the constituent elements shown in the above-mentioned embodiment, if the stated problem can be solved and the stated effect can be obtained, the configuration from which these constituent elements are deleted can be extracted as an invention. [Explanation of symbols]

[0161] 1. Vehicle 2. Body 3. Front windshield glass (windshield) 4···Cowl top cover 5. Upper dash panel 6. Opening 7 Bottom 8. Fresh air intake passage 9. Engine Room 10. Instrument panel 14. Vehicle air conditioning system (air conditioning system) 15. Vehicle air conditioning system (air conditioning system) 16 Blower Cooling Unit 17 Heater unit 18. First air conditioning duct 19. Fresh air intake 20. Inside air intake 21. Second air conditioning duct 25. Indoor / outdoor air switching door 26...Inside / outside air switching actuator (actuator) 27 Blower fan 28 Blower motor 29. Evaporator 30···Compressor 31. Air conditioner clutch 35 Defroster outlet 36 Ventilation outlet 37 Heater outlet 40 Defroster duct 41 Ventilation duct 42 Heater duct 43 Defroster door 44 Ventilation door 45···Heater door 46a Door switching actuator (actuator) 46b Door switching actuator (actuator) 46c Door switching actuator (actuator) 47 Heater core 48···Air mix door 49. Opening adjustment actuator (actuator) 50···Air conditioning control unit 52 Operation panel 53. Interior air temperature sensor 54 Outside air temperature sensor 55. Solar radiation sensor 56 Water temperature sensor 57 Body angle sensor 58 Raindrop sensor 59 Humidity Sensor 60···Evaporator temperature sensor A Correction amount B Correction amount C Correction amount D. Driving force upper limit E. Amount of outside air mixed in F···Inside air intake opening (opening) G... Amount of air mixed in G1: First internal air intake amount G2: Second internal air intake amount G3: Third internal air intake amount S: Standard amount of air mixed in Tset: Set temperature Tin...Vehicle interior temperature Tout...Temperature outside the vehicle Tth: Threshold temperature △R...capacity difference

Claims

1. an inside / outside air switching door for adjusting the amount of outside air mixed in through the outside air inlet and the amount of inside air mixed in through the inside air inlet; a first mixed air amount calculation means for calculating a first mixed air amount for realizing high air conditioning efficiency based on an air conditioning load; a second mixed air amount calculation means for calculating a second mixed air amount for suppressing water intrusion through the outside air inlet based on a vehicle body angle and weather conditions; and an internal air mixing amount setting means for setting the internal air mixing amount by the internal / external air switching door based on the larger value of the first internal air mixing amount or the second internal air mixing amount.

2. The vehicle interior humidity control system further includes a third internal air amount calculation means for calculating a third internal air amount for suppressing window fogging based on the humidity information in the vehicle interior, The vehicle air conditioning system according to claim 1, characterized in that the internal air mixing amount setting means sets the internal air mixing amount based on the third internal air mixing amount when the third internal air mixing amount is equal to or greater than the second internal air mixing amount, even if the first internal air mixing amount is greater than the second internal air mixing amount.

3. 3. The vehicle air conditioning system according to claim 2, wherein the internal air mixing amount setting means sets the internal air mixing amount based on the second internal air mixing amount in a state in which the dehumidification efficiency is increased when the second internal air mixing amount is greater than the third internal air mixing amount and there is a margin of dehumidification capacity.

4. 2. The vehicle air conditioning system according to claim 1, wherein the second mixed inside air amount calculation means calculates a past average value and a latest average value for a predetermined number of cycles from a plurality of the second mixed inside air amounts calculated continuously at each set time, and when the past average value is greater than the latest average value for a set time, replaces the second mixed inside air amount with the latest average value.

5. an inside / outside air switching door for adjusting the amount of outside air mixed in through the outside air inlet and the amount of inside air mixed in through the inside air inlet; a control unit for controlling the inside / outside air switching door, The control unit calculates a first amount of internal air mixing to achieve high air conditioning efficiency based on the air conditioning load, calculates a second amount of internal air mixing to suppress water intrusion from the external air inlet based on the vehicle body angle and weather conditions, and sets the amount of internal air mixing by the internal / external air switching door based on the larger value of the first amount of internal air mixing or the second amount of internal air mixing.

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