Vehicle air conditioning system

Abstract

To provide an air conditioner for a vehicle which can surely perform control to prevent a windshield from clouding when the position of a humidity sensor is apart from the windshield.SOLUTION: An air conditioner for a vehicle comprises: an outside air temperature sensor; an inside air humidity sensor; an air-conditioning duct; and an air-conditioning controller. The inside air humidity sensor is arranged apart from a windshield, the air-conditioning duct includes an outside air introduction port, an air-conditioning unit, and a defroster blowout port. The air-conditioning controller includes a temperature calculation part which calculates a glass temperature of the windshield, a determination part which determines whether clouding of the windshield occurs or not, and a defroster control part which controls to supply or stop air to the defroster blowout port. The determination part includes a first determination part which makes a determination based on the glass temperature and the humidity inside a cabin, and a second determination part which makes a determination based on the glass temperature and the amount of saturated water vapor at the outside air temperature.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an air conditioner for a vehicle. [Background technology]

[0002] An automobile is equipped with an air conditioner for vehicles that adjusts the temperature inside the vehicle cabin. The air conditioner for vehicles has a defroster outlet that blows air toward the inner surface of the windshield to prevent fogging on the inner surface of the windshield. The defroster outlet is provided on the instrument panel. For example, when the temperature outside the vehicle cabin is low and the temperature and humidity inside the vehicle cabin are high, the inner surface of the windshield may fog up. This is because the windshield is cooled by the outside air, causing condensation to form on the inner surface of the windshield. The air conditioner for vehicles removes fogging on the inner surface of the windshield by supplying heated air to the defroster outlet.

[0003] Patent Document 1 describes that in order to prevent the windshield from fogging up, the target post-evaporator temperature TEO is lowered when the humidity in the vehicle compartment detected by a humidity sensor is equal to or higher than a predetermined value. The vehicle air conditioner described in Patent Document 1 is configured to automatically increase the dehumidification capacity by lowering the target post-evaporator temperature TEO. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-267025 A Summary of the Invention [Problem to be solved by the invention]

[0005] Recently, vehicle air conditioners have been developed that determine whether or not fogging has occurred on the windshield and automatically start and stop supplying air to the defroster outlet. Such vehicle air conditioners determine whether or not fogging has occurred on the windshield based on information obtained from various sensors that detect the outside air temperature, the temperature and humidity inside the vehicle compartment, etc.

[0006] To determine whether fogging has occurred, it is necessary to accurately measure the humidity near the inner surface of the windshield. To measure this humidity, it is optimal to place a humidity sensor near the inner surface of the windshield. For example, a humidity sensor can be directly installed on the inner surface of the windshield, or installed on an inner mirror attached to the windshield. However, when placing a new humidity sensor near the inner surface of the windshield, it is necessary to prepare a board on which to mount the humidity sensor and to wire a wire harness to the board on which the humidity sensor is mounted. Adding a board or wiring a wire harness just for the humidity sensor results in high costs.

[0007] An object of the present invention is to provide an air conditioner for a vehicle that can reliably perform control to prevent fogging of the windshield even if the humidity sensor is located away from the windshield. [Means for solving the problem]

[0008] An air conditioning device for a vehicle according to one aspect of the present invention comprises: an outside air temperature sensor for detecting an outside air temperature outside the vehicle cabin; an interior humidity sensor for detecting the humidity inside the vehicle interior; The air conditioning duct that sends air into the vehicle cabin, An air conditioning controller for controlling the temperature and volume of the air, The inside air humidity sensor is disposed at a position away from the windshield, The air conditioning duct is An outside air intake port that takes in air from outside the vehicle cabin; an air conditioning unit for adjusting the temperature of the air taken into the air conditioning duct; a defroster outlet for blowing air that has passed through the air conditioning unit toward an inner surface of the windshield, The air conditioning controller includes: a temperature calculation unit that calculates a glass temperature of the windshield; A determination unit that determines whether fogging has occurred on the windshield; a defroster control unit that controls supply and stop of air from the air conditioning duct to the defroster outlet based on a determination result of the determination unit, The determination unit is a first determination unit that performs a first determination process when air is not taken in through the outside air inlet or when air supply to the defroster outlet is stopped; a second determination unit that performs a second determination process when air is taken in through the outside air inlet and air is supplied to the defroster outlet, The first determination process determines whether or not fogging has occurred based on the glass temperature and the humidity, The second determination process determines whether or not fogging has occurred based on the amount of saturated water vapor at the outside air temperature relative to the amount of saturated water vapor at the glass temperature. Effect of the Invention

[0009] In the above-mentioned vehicle air conditioner, the process of the determination unit for determining whether fogging has occurred on the windshield differs between when air is taken in from the outside air inlet and supplied to the defroster outlet and when it is not. In the former case, in the above-mentioned vehicle air conditioner, the second determination unit performs a second determination process for determining whether fogging has occurred using the amount of saturated water vapor at the outside air temperature. This ensures that the defroster control unit can reliably control the windshield to prevent fogging, even if the inside air humidity sensor is located away from the windshield. According to the above-mentioned vehicle air conditioner, the inside air humidity sensor can be located away from the windshield. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a vehicle air conditioner according to an embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing an example of a windshield and an instrument panel provided in a vehicle, as viewed from inside the vehicle cabin. [Diagram 3] FIG. 3 is a diagram showing a process flow of the determination unit in the vehicle air conditioner according to the embodiment. [Figure 4] FIG. 4 is a diagram for explaining a determination method of the first determination unit in the vehicle air conditioner according to the embodiment. [Diagram 5] FIG. 5 is another diagram for explaining the determination method of the first determination unit in the vehicle air conditioner according to the embodiment. [Figure 6] FIG. 6 is a diagram for explaining a determination method of the second determination unit in the vehicle air conditioner according to the embodiment. [Figure 7] FIG. 7 is another diagram for explaining the determination method of the second determination unit in the vehicle air conditioner according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific example of a vehicle air conditioner according to an embodiment of the present invention will be described with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals.

[0012] Vehicle Air Conditioning System An embodiment of a vehicle air conditioner 1 will be described with reference to Figs. 1 and 2. The vehicle air conditioner 1 conditions the air inside the vehicle cabin. The vehicle air conditioner 1 includes sensors 2, an air conditioning duct 3, and an air conditioning controller 6. The vehicle air conditioner 1 adjusts the temperature of air taken into the air conditioning duct 3, and sends the temperature-adjusted air from the air conditioning duct 3 into the vehicle cabin. Fig. 2 is a front view of a windshield 10 and an instrument panel 11 as viewed from inside the vehicle cabin. The instrument panel 11 is disposed in the front of the vehicle cabin. The windshield 10 is provided at the front end of the instrument panel 11. The surface of the instrument panel 11 facing the rear of the vehicle cabin is defined as the front.

[0013] One of the features of the vehicle air conditioner 1 of the embodiment is that the air conditioning controller 6 includes a determination unit 62 that determines whether fogging has occurred on the windshield 10. The determination unit 62 determines whether fogging has occurred by different processes depending on whether the mode is inside air mode or outside air mode and the defroster is not operating, or outside air mode and the defroster is operating. The determination unit 62 includes a first determination unit 621 that makes a determination based on the glass temperature and the humidity in the vehicle cabin, and a second determination unit 622 that makes a determination based on the glass temperature and the amount of saturated water vapor at the outside air temperature.

[0014] (Sensors) The sensors 2 are various sensors that detect environmental conditions of the vehicle. The sensors 2 include an outside air temperature sensor 21 and an inside air humidity sensor 22. The outside air temperature sensor 21 is a sensor that detects the outside air temperature outside the vehicle cabin. The outside air temperature sensor 21 is provided outside the vehicle cabin. The outside air temperature sensor 21 is provided, for example, in an opening of a bumper (not shown).

[0015] The inside air humidity sensor 22 is a sensor that detects the humidity in the vehicle cabin. The inside air humidity sensor 22 is disposed at a position away from the windshield 10. The position away from the windshield 10 means a position excluding the vicinity of the inner surface of the windshield 10. Specifically, the position is a position that is far enough away that it is not immediately affected by the temperature and humidity of the air blown out from the defroster outlet 51. Furthermore, the inside air humidity sensor 22 may be provided on a board of another electric device. In this case, this board can be used as a board for mounting the inside air humidity sensor 22. The inside air humidity sensor 22 is provided, for example, in the instrument panel 11 shown in FIG. 2. In this embodiment, the inside air humidity sensor 22 is provided on a board of an existing electric device attached to the instrument panel 11. Specifically, the inside air humidity sensor 22 is provided on a board of an electric device such as the center display 12 or the operation panel 13. The operation panel 13 is, for example, a heater control panel. The inside air humidity sensor 22 does not have to be provided in the instrument panel 11, and may be provided on a board of an existing electrical device arranged in the vehicle cabin. Since the inside air humidity sensor 22 is provided on a board of an existing electrical device, there is no need to prepare a separate board for mounting the inside air humidity sensor 22 or to change the layout of a wire harness (not shown). This makes it possible to suppress the cost associated with providing the inside air humidity sensor 22. Since there is no need to provide a new board just for the inside air humidity sensor 22, there is little risk of an increase in weight or a decrease in productivity.

[0016] The indoor humidity sensor 22 is, for example, a known electronic humidity sensor. The humidity detected by the indoor humidity sensor 22 may be either relative humidity or absolute humidity. Absolute humidity is defined as the humidity per 1 m 3 This is the volumetric absolute humidity, which indicates the amount of water vapor contained per unit of air, and is expressed in g / m 3 In this embodiment, the inside air humidity sensor 22 is a sensor that detects the relative humidity. The absolute humidity can be calculated by multiplying the amount of saturated water vapor by the relative humidity.

[0017] The inside air humidity sensor 22 in this embodiment is a temperature and humidity sensor integrated with the inside air temperature sensor 23. The inside air temperature sensor 23 is a sensor that detects the temperature in the vehicle cabin, i.e., the inside air temperature. In this embodiment, the temperature and humidity sensor integrated with the inside air humidity sensor 22 and the inside air temperature sensor 23 is mounted on the board of the center display 12, but is not limited to this. The temperature and humidity sensor may be mounted on the board of the operation panel 13, for example. Unlike this embodiment, the inside air humidity sensor 22 and the inside air temperature sensor 23 may be independent sensors. The inside air temperature sensor 23 may be provided, for example, in the instrument panel 11, similar to the inside air humidity sensor 22. The inside air temperature sensor 23 is installed, for example, on the board of an electronic device attached to the instrument panel 11. The inside air humidity sensor 22 and the inside air temperature sensor 23 may be mounted on the same board or on different boards.

[0018] The sensors 2 may further include a solar radiation sensor 24 and other sensors. The solar radiation sensor 24 detects the amount of solar radiation transmitted through the windshield 10. The solar radiation sensor 24 is provided on the upper surface of the instrument panel 11, for example.

[0019] The other sensors are, for example, a vehicle speed sensor (not shown) and an occupant detection sensor (not shown). The vehicle speed sensor is a sensor that detects the vehicle speed. The occupant detection sensor is a sensor that detects an occupant seated in a seat. The occupant detection sensor can be, for example, a load sensor that detects the load on the seat, or a seat belt sensor that detects whether the seat belt is fastened. In the case of a load sensor, it is possible to determine whether or not an occupant is seated in the seat by detecting the load on the seat. In the case of a seat belt sensor, it is possible to determine whether or not an occupant is seated in the seat by detecting whether or not the seat belt is fastened.

[0020] (Air conditioning ducts) The air conditioning duct 3 is a duct through which air flows to be sent into the vehicle cabin. The air conditioning duct 3 has an inlet 30, an air conditioning unit 4, and an outlet 50. The inlet 30 is a portion that takes in air into the air conditioning duct 3. The outlet 50 is a portion that blows air from the air conditioning duct 3 into the vehicle cabin. In the air conditioning duct 3, the direction from which air flows is upstream, and the direction to which air flows is downstream. The inlet 30 is provided at the most upstream position of the air conditioning duct 3. The outlet 50 is provided at the most downstream position of the air conditioning duct 3. The air conditioning unit 4 is provided in the middle of the air conditioning duct 3. The basic configuration of the air conditioning duct 3 can utilize the configuration of a known air conditioning duct.

[0021] The air conditioning duct 3 is equipped with a blower 35. The blower 35 is disposed upstream of the air conditioning unit 4. When the blower 35 rotates, air is sucked into the air conditioning duct 3 from the inlet 30, and the sucked air is sent to the outlet 50 through the air conditioning unit 4. By adjusting the output of the blower 35, the volume of air blown out from the outlet 50 is adjusted.

[0022] (Inlet) The inlet 30 includes an outside air inlet 31 and an inside air inlet 32. The outside air inlet 31 is a portion that takes in air outside the vehicle cabin. The inside air inlet 32 ​​is a portion that takes in air inside the vehicle cabin. A switching door 33 that opens and closes the outside air inlet 31 and the inside air inlet 32 ​​is provided at a branch point between a flow path leading to the outside air inlet 31 and a flow path leading to the inside air inlet 32. When the switching door 33 closes the inside air inlet 32, the outside air inlet 31 is open, and air is taken in from the outside air inlet 31 to the air conditioning duct 3. When the switching door 33 closes the outside air inlet 31, the inside air inlet 32 ​​is open, and air is taken in from the inside air inlet 32 ​​to the air conditioning duct 3.

[0023] (Air conditioning unit) The air conditioning unit 4 adjusts the temperature of the air taken into the air conditioning duct 3. The air conditioning unit 4 has an evaporator 41, a heater core 42, and an air mix door 43. The evaporator 41 is a component that cools the air taken into the air conditioning duct 3. The configuration of the evaporator 41 is the same as that of a known one. A refrigerant circulates in the evaporator 41. The air passing through the evaporator 41 is cooled by the refrigerant circulating through the evaporator 41. An evaporator temperature sensor 41s is provided downstream of the evaporator 41. The evaporator temperature sensor 41s is a sensor that detects the temperature of the air that has passed through the evaporator 41.

[0024] The heater core 42 is a component that heats the air that has passed through the evaporator 41. The heater core 42 is disposed downstream of the evaporator 41. The configuration of the heater core 42 is the same as that of a known one. Coolant that cools an engine (not shown) circulates through the heater core 42. The coolant, which has been heated by the heat of the engine, circulates through the heater core 42, thereby heating the air that passes through the heater core 42. The engine is provided with a water temperature sensor 42s that detects the temperature of the coolant.

[0025] The air mix door 43 is a member that adjusts the ratio of air passing through the heater core 42 to air bypassing the heater core 42. The air mix door 43 is disposed between the evaporator 41 and the heater core 42. In other words, the air mix door 43 is disposed downstream of the evaporator 41 and upstream of the heater core 42. The configuration of the air mix door 43 is the same as that of a known one. By adjusting the opening degree of the air mix door 43, the temperature of the air blown out from the air outlet 50 is adjusted.

[0026] (Air outlet) The air outlet 50 includes a defroster air outlet 51, a face air outlet 52, and a foot air outlet 53. The defroster air outlet 51 is a portion that blows air toward the inner surface of the windshield 10. A defroster door 51d that opens and closes the defroster air outlet 51 is provided in a flow path connected to the defroster air outlet 51. The face air outlet 52 is a portion that blows air toward the upper body of the occupant. A face door 52d that opens and closes the face air outlet 52 is provided in a flow path connected to the face air outlet 52. The foot air outlet 53 is a portion that blows air toward the feet of the occupant. A foot door 53d that opens and closes the foot air outlet 53 is provided in a flow path connected to the foot air outlet 53.

[0027] 2, the defroster outlet 51 is provided on the upper surface of the instrument panel 11. The face outlet 52 is provided on the upper front surface of the instrument panel 11. The foot outlet 53 is provided on the lower portion of the instrument panel 11.

[0028] (Air conditioning controller) The air conditioning controller 6 is a device that controls the temperature and volume of air sent into the vehicle cabin. In addition to controlling the air conditioning inside the vehicle cabin, the air conditioning controller 6 also performs control to prevent fogging of the windshield 10. The air conditioning controller 6 is typically configured by a computer. The computer includes a processor, a memory, a timer, and the like. The memory stores control programs to be executed by the processor and various data. The processor reads out and executes the control programs stored in the memory.

[0029] The air conditioning controller 6, for example, adjusts the temperature and volume of air blown out from the air outlet 50, switches the inlet 30, and switches the air outlet 50. The temperature is adjusted by controlling the opening of the air mix door 43. The volume of air is adjusted by controlling the output of the blower 35. The inlet 30 is switched between the outside air inlet 31 and the inside air inlet 32 ​​by controlling the opening and closing of the switching door 33. The air outlet 50 is switched to one of the defroster outlet 51, the face outlet 52, and the foot outlet 53 by controlling the opening and closing of the defroster door 51d, the face door 52d, and the foot door 53d.

[0030] The air conditioning controller 6 receives signals from switches 130 provided on the operation panel 13. The switches 130 include, for example, a temperature adjustment switch 13a, an air volume adjustment switch 13b, an inside / outside air selector switch 13c, a blowing mode switch 13d, a defroster switch 13e, an auto switch 13f, and an ON / OFF switch 13g. The temperature adjustment switch 13a is a switch for setting the temperature inside the vehicle cabin. The air volume adjustment switch 13b is a switch for setting the volume of air blown out from the air outlet 50. The inside / outside air selector switch 13c is a switch for switching between the outside air mode and the inside air mode by switching between the outside air inlet 31 and the inside air inlet 32. The outside air mode is a mode in which air outside the vehicle cabin is taken in from the outside air inlet 31. The inside air mode is a mode in which air inside the vehicle cabin is taken in from the inside air inlet 32.

[0031] The air outlet mode switch 13d is a switch for changing the air outlet mode by switching the air outlet 50. The air outlet mode is selected from, for example, a face mode, a foot mode, a bi-level mode, a foot / defroster mode, and a defroster mode. The face mode is a mode for blowing air from the face air outlet 52. The foot mode is a mode for blowing air from the foot air outlet 53. The bi-level mode is a mode for blowing air from both the face air outlet 52 and the foot air outlet 53. The foot / defroster mode is a mode for blowing air from both the foot air outlet 53 and the defroster air outlet 51. The defroster mode is a mode for blowing air from the defroster air outlet 51. The defroster switch 13e is a switch for setting the air outlet mode to the defroster mode.

[0032] The auto switch 13f is a switch for switching the automatic air conditioner ON / OFF. When the automatic air conditioner is ON, it automatically adjusts the temperature and volume of air blown out from the air outlet 50, switches the inlet 30, and switches the air outlet 50 so that the temperature in the vehicle cabin reaches the set temperature. The ON / OFF switch 13g is a switch for switching the vehicle air conditioner 1 ON / OFF.

[0033] The air conditioning controller 6 receives signals from the sensors 2. Specifically, the outside air temperature sensor 21 sends a signal corresponding to the outside air temperature. The inside air humidity sensor 22 sends a signal corresponding to the humidity in the vehicle cabin. The inside air temperature sensor 23 sends a signal corresponding to the inside air temperature. The solar radiation sensor 24 sends a signal corresponding to the amount of solar radiation transmitted through the windshield 10. Furthermore, the air conditioning controller 6 receives signals from an evaporator temperature sensor 41s and a water temperature sensor 42s. The evaporator temperature sensor 41s sends a signal corresponding to the temperature of the air that has passed through the evaporator 41. The water temperature sensor 42s sends a signal corresponding to the temperature of the cooling water circulating to the heater core 42. In this embodiment, the air conditioning controller 6 also receives signals from a vehicle speed sensor (not shown) and an occupant detection sensor (not shown). The vehicle speed sensor sends a signal corresponding to the vehicle speed. The occupant detection sensor sends a signal corresponding to the presence or absence of an occupant sitting in the seat.

[0034] The air conditioning controller 6 has a temperature calculation unit 61, a determination unit 62, and a defroster control unit 63.

[0035] (Temperature calculation section) The temperature calculation unit 61 calculates the glass temperature of the windshield 10. The glass temperature is calculated based on the outside air temperature and the temperature near the inner surface of the windshield 10. A known calculation method can be used to calculate the glass temperature. The temperature near the inner surface of the windshield 10 is affected by the temperature of the air blown out from the defroster outlet 51. When air is not blown out from the defroster outlet 51, that is, when the blowing mode is any of the face mode, the foot mode, and the bi-level mode, the temperature near the inner surface of the windshield 10 correlates with the temperature in the vehicle cabin, that is, the inside air temperature. In this case, the temperature near the inner surface of the windshield 10 can be regarded as the inside air temperature. Even when air is blown out from the defroster outlet 51, when air is taken in from the inside air inlet 32, that is, when the inside air mode is selected and the blowing mode is the foot / defroster mode or the defroster mode, there is a certain degree of correlation between the temperature near the inner surface of the windshield 10 and the inside air temperature. In this case, the temperature in the vicinity of the inner surface of the windshield 10 may be obtained by correcting the inside air temperature as necessary. The inside air temperature may be corrected using a known arithmetic expression.

[0036] On the other hand, when air is taken in from the outside air inlet 31 and air is blown out from the defroster outlet 51, that is, when the outside air mode is selected and the blowing mode is the foot / defroster mode or the defroster mode, the temperature of the air blown out from the defroster outlet 51 varies according to the outside air temperature. Therefore, there is almost no correlation between the temperature near the inner surface of the windshield 10 and the inside air temperature. In this case, the temperature near the inner surface of the windshield 10 can be regarded as the temperature of the air blown out from the defroster outlet 51. The temperature of the air blown out from the defroster outlet 51 can be calculated, for example, from the temperature of the air that has passed through the evaporator 41, the temperature of the cooling water circulating in the heater core 42, and the opening degree of the air mix door 43. Alternatively, the temperature of the air blown out from the defroster outlet 51 may be detected by a temperature sensor attached to the defroster outlet 51.

[0037] In this embodiment, data in the form of a table showing the relationship between the outside air temperature and the glass temperature corresponding to the temperature near the inner surface of the windshield 10 is stored in the memory. The temperature calculation unit 61 obtains the glass temperature from this tabulated data according to the outside air temperature and the temperature near the inner surface of the windshield 10. The outside air temperature is obtained from the outside air temperature sensor 21. The glass temperature may be corrected according to, for example, the amount of solar radiation passing through the windshield 10 and the vehicle speed. The greater the amount of solar radiation, the more the windshield 10 is heated by the solar radiation, and the more likely the glass temperature is to rise. The greater the vehicle speed, the more the windshield 10 is cooled by the outside air, and the more likely the glass temperature is to fall. The amount of solar radiation can be obtained from the solar radiation sensor 24. The vehicle speed can be obtained from the vehicle speed sensor.

[0038] (Judgment Department) The determination unit 62 determines whether or not fogging has occurred on the windshield 10. Determining whether or not fogging has occurred here means determining whether or not a condition for fogging to occur or a condition for which fogging is likely to occur is met, and includes either a case where fogging has occurred or a case where fogging is predicted to occur as a determination target. The determination unit 62 includes a first determination unit 621 and a second determination unit 622. The first determination unit 621 performs a first determination process when air is not taken in from the outside air inlet 31 or the supply of air to the defroster outlet 51 is stopped. The second determination unit 622 performs a second determination process when air is taken in from the outside air inlet 31 and air is supplied to the defroster outlet 51. The first determination process determines whether or not fogging has occurred based on the glass temperature and the humidity detected by the inside air humidity sensor 22. The second determination process determines whether or not fogging has occurred based on the amount of saturated water vapor at the outside air temperature relative to the amount of saturated water vapor at the glass temperature.

[0039] The occurrence of fogging of the windshield 10 can be determined based on the glass temperature and the humidity near the inner surface of the windshield 10. 3If the amount of water vapor in the air, i.e., the absolute humidity, is equal to or greater than the saturated water vapor amount at the glass temperature, fogging will occur on the inner surface of the windshield 10. In other words, when the glass temperature falls below the dew point temperature, fogging will occur on the windshield 10.

[0040] The process of determining whether or not the windshield 10 is fogged up in the determination unit 62 differs depending on the setting state of the air conditioning controller 6. Specifically, in a first setting state in which air is not taken in from the outside air inlet 31 or the supply of air to the defroster outlet 51 is stopped, the first determination unit 621 performs a first determination process. In cases other than the first setting state, that is, in a second setting state in which air is taken in from the outside air inlet 31 and air is supplied to the defroster outlet 51, the second determination unit 622 performs a second determination process. The first setting state is specifically a state in which the mode is the inside air mode or a state in which the blowing mode is any of the face mode, foot mode, and bi-level mode. In other words, even if the mode is the outside air mode, if the mode is any of the face mode, foot mode, and bi-level mode, it is the first setting state. Also, even if the mode is the foot / defroster mode or the defroster mode, if the mode is the inside air mode, it is the first setting state. The second setting state is a state in which the outside air mode is selected and the blowing mode is selected to be the foot / defroster mode or the defroster mode.

[0041] The reason why the process for determining whether or not fogging has occurred on the windshield 10 differs between the first setting state and the second setting state is as follows. In the first setting state, the humidity near the inner surface of the windshield 10 correlates with the humidity in the vehicle cabin. In this case, the humidity near the inner surface of the windshield 10 can be regarded as the humidity detected by the inside air humidity sensor 22. In the first setting state, the first determination unit 621 performs a first determination process for determining whether or not fogging has occurred using the humidity detected by the inside air humidity sensor 22. The details of the first determination process will be described later. On the other hand, in the second setting state, the humidity near the inner surface of the windshield 10 is affected by the humidity of the air blown out from the defroster outlet 51. The humidity of the air blown out from the defroster outlet 51 is affected by the humidity of the air outside the vehicle cabin taken into the air conditioning duct 3 from the outside air inlet 31. Therefore, there is almost no correlation between the humidity near the inner surface of the windshield 10 and the humidity detected by the inside air humidity sensor 22. In the case of the second setting state, it is difficult to determine whether fogging has occurred using the humidity detected by the inside air humidity sensor 22. The second determination process in the second determination unit 622 determines whether fogging has occurred using the saturated water vapor amount at the outside air temperature. The second determination process will be described in detail later.

[0042] The process flow of the determination unit 62 will be described in detail with reference to Fig. 3. In step S11, the determination unit 62 acquires the setting state from the air conditioning controller 6 and determines whether it is the second setting state. If the result in step S11 is No, i.e., if it is the first setting state, the process proceeds to step S21, where the first determination unit 621 performs a first determination process. If the result in step S11 is Yes, i.e., if it is the second setting state, the process proceeds to step S22, where the second determination unit 622 performs a second determination process.

[0043] First Judgment Unit and First Judgment Process The first determination process in the first determination unit 621 is performed as follows. In the first determination process, the glass temperature and the humidity near the inner surface of the windshield 10 are acquired. The glass temperature is acquired from the temperature calculation unit 61. The humidity near the inner surface of the windshield 10 is acquired as the absolute humidity in the vehicle cabin from the humidity detected by the inside air humidity sensor 22. When the humidity detected by the inside air humidity sensor 22 is the relative humidity, the absolute humidity can be obtained from the amount of saturated water vapor at the inside air temperature and the relative humidity. The inside air temperature is acquired from the inside air temperature sensor 23. In the first determination process, the presence or absence of fogging is determined based on the glass temperature and the absolute humidity in the vehicle cabin. Specifically, the amount of saturated water vapor at the glass temperature is compared with the absolute humidity in the vehicle cabin. When the absolute humidity in the vehicle cabin is equal to or greater than a predetermined value relative to the amount of saturated water vapor at the glass temperature, it is determined that fogging has occurred. When the absolute humidity in the vehicle cabin is less than a predetermined value relative to the amount of saturated water vapor at the glass temperature, it is determined that fogging has not occurred. 3, if the answer is Yes in step S21, that is, if the result of the first determination process is that fogging has occurred, the process proceeds to step S31, where a defroster control unit 63, which will be described later, supplies air to the defroster outlet 51. If the answer is No in step S21, that is, if the result of the first determination process is that fogging has not occurred, the process proceeds to step S32, where the supply of air to the defroster outlet 51 is stopped. After step S31 or step S32, the process returns to step S11, and the processes from step S11 onwards are repeated.

[0044] A specific example of a method for determining the occurrence of fogging in the first determination process will be described with reference to Fig. 4 and Fig. 5. Fig. 4 and Fig. 5 show the relationship between the air temperature and the amount of water vapor contained in the air. The horizontal axis of Fig. 4 and Fig. 5 is temperature, and the vertical axis is water vapor per 1 m of air. 3The temperature on the horizontal axis represents the glass temperature or the inside air temperature. In Figs. 4 and 5, the solid curved line is a saturation line showing the saturated water vapor amount at each temperature. The dashed curved line is a judgment line showing a criterion for judging the occurrence or non-occurrence of fogging. The judgment line can be set appropriately as long as it is equal to or lower than the saturated water vapor amount at each temperature. The judgment line may be the same as the saturation line or may be lower than the saturation line. In this embodiment, the judgment line is set lower than the saturation line. The judgment line shown in Figs. 4 and 5 is set to a value that is 75% of the saturation line. The humidity in the vehicle cabin is more likely to fluctuate as the number of occupants increases, so the judgment line may be changed appropriately according to the number of occupants. The number of occupants can be acquired from an occupant detection sensor.

[0045] In the first judgment process, if the absolute humidity inside the vehicle cabin is equal to or higher than the judgment line for the glass temperature, it is judged that fogging has occurred. If the absolute humidity inside the vehicle cabin is less than the judgment line for the glass temperature, it is judged that fogging has not occurred. In Figs. 4 and 5, the hatched bars indicate the absolute humidity inside the vehicle cabin. The open bars indicate the amount of saturated water vapor at the glass temperature. In the example of Fig. 4, the temperature inside the vehicle cabin is 30°C, the absolute humidity inside the vehicle cabin is 8.0 g / m 3 The glass temperature is 15°C. The amount of saturated water vapor at a glass temperature of 15°C is 12.8g / m 3 The judgment line at 15°C is 9.6 g / m 3 In this case, since the absolute humidity inside the vehicle cabin is below the judgment line, it is judged that no fogging has occurred. FIG. 5 shows a state in which the humidity inside the vehicle cabin has increased and the glass temperature has decreased from the state shown in FIG. 4. The increase in humidity inside the vehicle cabin is caused, for example, by an increase in the number of passengers. The decrease in glass temperature is caused, for example, by a decrease in the outside air temperature. In the example of FIG. 5, the temperature inside the vehicle cabin is 30°C, the absolute humidity inside the vehicle cabin is 9.0 g / m 3 The glass temperature is 10°C. The amount of saturated water vapor at a glass temperature of 10°C is 9.3g / m 3 The judgment line at 10°C is about 7.0 g / m 3In this case, since the absolute humidity in the vehicle interior is equal to or higher than the judgment line, it is judged that fogging has occurred.

[0046] <Second judgment unit / second judgment process> The second determination process in the second determination unit 622 is performed as follows. In the second determination process, the glass temperature and the amount of saturated water vapor at the outside air temperature are acquired. The amount of saturated water vapor at the outside air temperature is obtained from the outside air temperature detected by the outside air temperature sensor 21. The amount of saturated water vapor at the outside air temperature means the absolute humidity when the relative humidity at that temperature is 100%. second The determination process determines whether fogging has occurred based on the amount of saturated water vapor at the outside air temperature relative to the amount of saturated water vapor at the glass temperature. Specifically, the amount of saturated water vapor at the glass temperature is compared with the amount of saturated water vapor at the outside air temperature. If the amount of saturated water vapor at the outside air temperature is equal to or greater than a predetermined value relative to the amount of saturated water vapor at the glass temperature, it is determined that fogging has occurred. If the amount of saturated water vapor at the outside air temperature is less than a predetermined value relative to the amount of saturated water vapor at the glass temperature, it is determined that fogging has not occurred. As shown in FIG. 3, if the result of step S22 is Yes, that is, if the result of the second determination process is that fogging has occurred, the process proceeds to step S31, where the defroster control unit 63 described later supplies air to the defroster outlet 51. If the result of step S22 is No, that is, if the result of the second determination process is that fogging has not occurred, the process proceeds to step S32, where the supply of air to the defroster outlet 51 is stopped. After step S31 or step S32, the process returns to step S11, and the process from step S11 onwards is repeated.

[0047] Here, in the second determination process, the reason for determining whether fogging has occurred using the amount of saturated water vapor at the outside air temperature is as follows. In the second setting state, the amount of water vapor contained in the air blown out from the defroster outlet 51 may be lower than the amount of water vapor contained in the air outside the vehicle cabin taken into the air conditioning duct 3 from the outside air inlet 31, but it will not exceed it. When the relative humidity of the air outside the vehicle cabin is 100%, the amount of water vapor contained in the air blown out from the defroster outlet 51 is maximum. In other words, the absolute humidity of the air blown out from the defroster outlet 51 is equal to or lower than the amount of saturated water vapor at the outside air temperature. In the second determination process, the relative humidity of the air outside the vehicle cabin is assumed to be 100%, and the absolute humidity of the air blown out from the defroster outlet 51 is regarded as the amount of saturated water vapor at the outside air temperature, regardless of the actual humidity of the air blown out from the defroster outlet 51. In the second determination process, the occurrence of fogging can be reliably determined by comparing the amount of saturated water vapor at the glass temperature with the amount of saturated water vapor at the outside air temperature.

[0048] A specific example of a method for determining whether or not fogging has occurred in the second determination process will be described with reference to Figures 6 and 7. Figures 6 and 7 show the relationship between the air temperature and the amount of water vapor contained in the air, similar to Figures 4 and 5. The temperature on the horizontal axis represents the glass temperature or the outside air temperature. In Figures 6 and 7, the solid curved lines are saturation lines indicating the amount of saturated water vapor at each temperature. The dashed curved lines are determination lines indicating the criteria for determining whether or not fogging has occurred. The saturation line and determination line are the same as those in Figures 4 and 5.

[0049] In the second judgment process, if the amount of saturated water vapor at the outside air temperature is equal to or greater than the judgment line at the glass temperature, it is judged that fogging has occurred. If the amount of saturated water vapor at the outside air temperature is less than the judgment line at the glass temperature, it is judged that fogging has not occurred. In Figures 6 and 7, the hatched bars indicate the amount of saturated water vapor at the outside air temperature. The open bars indicate the amount of saturated water vapor at the glass temperature. In the example of Figure 6, the outside air temperature is 7.5°C, the amount of saturated water vapor at the outside air temperature is 8.0 g / m 3 The glass temperature is 10°C. The amount of saturated water vapor at a glass temperature of 10°C is 9.3g / m3 The judgment line at 10°C is about 7.0 g / m 3 In this case, since the amount of saturated water vapor at the outside air temperature is equal to or higher than the judgment line, it is judged that fogging has occurred. FIG. 7 shows a state in which the glass temperature has risen from the state shown in FIG. 6. The cause of this rise in glass temperature is, for example, the temperature of the air blown out from the defroster outlet 51. In the example of FIG. 7, the outside air temperature is 7.5°C and the glass temperature is 15°C. The amount of saturated water vapor at a glass temperature of 15°C is 12.8 g / m 3 The judgment line at 15°C is 9.6 g / m 3 In this case, since the amount of saturated water vapor at the outside air temperature is less than the judgment line, it is judged that no fogging has occurred.

[0050] (Defroster control unit) The defroster control unit 63 controls the supply and stop of air from the air conditioning duct 3 to the defroster outlet 51 based on the judgment result of the judgment unit 62. In the above-mentioned first setting state, if the first judgment process in the first judgment unit 621 judges that fogging has occurred, the defroster control unit 63 starts supplying air to the defroster outlet 51 (step S31 shown in FIG. 3). Specifically, the blowing mode is changed to the foot / defroster mode or the defroster mode. In this embodiment, the defroster control unit 63 changes the blowing mode to the outside air mode at the same time as changing the blowing mode. If the first judgment process judges that fogging has not occurred, the defroster control unit 63 maintains the state in which the supply of air to the defroster outlet 51 is stopped (step S32 shown in FIG. 3). Specifically, the blowing mode is maintained in any one of the face mode, the foot mode, and the bi-level mode.

[0051] In the above-mentioned second setting state, if the second determination process in the second determination unit 622 determines that fogging has occurred, the defroster control unit 63 continues to supply air to the defroster outlet 51 (step S31 shown in FIG. 3). For example, the blowing mode is maintained in the foot / defroster mode or the defroster mode. If the first determination process determines that fogging has not occurred, the defroster control unit 63 stops supplying air to the defroster outlet 51 (step S32 shown in FIG. 3). For example, the blowing mode is changed to any one of the face mode, the foot mode, and the bi-level mode.

[0052] A specific example of the control of the defroster control unit 63 will be described. For example, in a state where the blowing mode is set to the foot mode, under environmental conditions where the determination result of the first determination process indicates that fogging does not occur, the foot mode is maintained. In environmental conditions where the determination result of the first determination process indicates that fogging occurs, the supply of air to the defroster outlet 51 is started, and the mode transitions to the foot / defroster mode. When transitioning to the foot / defroster mode, the mode may be switched from the inside air mode to the outside air mode. In a state where the blowing mode has transitioned to the foot / defroster mode, under environmental conditions where the determination result of the second determination process indicates that fogging occurs, the foot / defroster mode is maintained. In environmental conditions where the determination result of the second determination process indicates that fogging does not occur, the supply of air to the defroster outlet 51 is stopped, and the mode transitions to the foot mode. When transitioning to the foot mode, the mode may be switched from the outside air mode to the inside air mode.

[0053] The present invention is not limited to these examples, but is indicated by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. In the above-mentioned embodiment, when the defroster control unit 63 starts supplying air to the defroster outlet 51, in addition to switching from the inside air mode to the outside air mode, any of the following operations (A) to (C) may be performed. (A) The temperature of the evaporator 41 is reduced. (B) The mode is changed to the semi-inside air mode. (C) The opening degree of the air mix door 43 is changed to increase the temperature of the air blown out from the defroster outlet 51. The semi-inside air mode is a mode in which the outside air inlet 31 and the inside air inlet 32 ​​are each half-opened, and air is taken in from both the outside air inlet 31 and the inside air inlet 32. By any of the above operations (A) to (C), it is possible to reduce the humidity of the air taken in the air conditioning duct 3. In the semi-inside air mode, if the majority of the air taken into the air conditioning duct 3 is outside air and the humidity near the inner surface of the windshield 10 has little correlation with the humidity detected by the inside air humidity sensor 22, the second setting state may be regarded as being in, and a second judgment process may be performed. [Explanation of symbols]

[0054] 1. Vehicle air conditioning system 2 Sensors 21 Outside air temperature sensor, 22 Inside air humidity sensor 23 Inside air temperature sensor, 24 Solar radiation sensor 3. Air conditioning ducts 30 Introduction 31 outside air inlet, 32 inside air inlet 35 Blower 4 Air Conditioning Unit 41 Evaporator, 41s Evaporator temperature sensor 42 heater core, 42s water temperature sensor 43 Air Mix Door 50 Air Outlet 51 Defroster vent, 51d Defroster door 52 face vent, 52d face door 53 foot outlet, 53d foot door 6 Air conditioning controller 61 Temperature calculation section 62 Judgment section 621 First judgment section, 622 Second judgment section 63 Defroster control unit 10 Windshield 11. Instrument Panel 12 Center display 13 Operation Panel 13a Temperature control switch 13b Airflow control switch 13c Indoor / outdoor air changeover switch 13d Bubble mode switch 13e Defroster switch 13f Auto Switch 13g ON / OFF switch

Claims

[Claim 1] an outside air temperature sensor for detecting an outside air temperature outside the vehicle cabin; an interior humidity sensor for detecting the humidity inside the vehicle interior; The air conditioning duct that sends air into the vehicle cabin, An air conditioning controller for controlling the temperature and volume of the air, The inside air humidity sensor is disposed at a position away from the windshield, The air conditioning duct is An outside air intake port that takes in air from outside the vehicle cabin; an air conditioning unit for adjusting the temperature of the air taken into the air conditioning duct; a defroster outlet for blowing air that has passed through the air conditioning unit toward an inner surface of the windshield, The air conditioning controller includes: a temperature calculation unit that calculates a glass temperature of the windshield; A determination unit that determines whether fogging has occurred on the windshield; a defroster control unit that controls supply and stop of air from the air conditioning duct to the defroster outlet based on a determination result of the determination unit, The determination unit is a first determination unit that performs a first determination process when air is not taken in through the outside air inlet or when air supply to the defroster outlet is stopped; a second determination unit that performs a second determination process when air is taken in through the outside air inlet and air is supplied to the defroster outlet, The first determination process determines whether or not fogging has occurred based on the glass temperature and the humidity, The second determination process determines whether or not fogging has occurred based on a saturated water vapor amount at the outside air temperature relative to a saturated water vapor amount at the glass temperature, assuming that the relative humidity of the air outside the vehicle compartment is 100%. Vehicle air conditioning system.

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