JP2002370521A - Air-conditioner for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure an anti-fogging property of window glass and secure heating performance in a cabin, with compatibility. SOLUTION: At least a foot mode for diffusing air mainly from a foot opening part and for diffusing a small volume of air from a defroster opening part, and a foot defroster mode for reducing a foot diffusing air volume compared with that in the foot mode and for increasing a defroster diffusing air volume are allowed to be set, the foot mode is selected when a target diffusing temperature TAO of the diffused air is a prescribed temperature or more, the foot defroster mode is selected instead of the foot mode when the target diffusing temperature TAO is lower than a target diffusing temperature fogging limit temperature determined by a speed of a vehicle and an outside air temperature even when the target diffusing temperature TAO is the prescribed temperature or more, and the target diffusing temperature fogging limit temperature is corrected to the high-temperature side based on increase of humidity in the cabin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air-conditioning system for an auto-controlled vehicle which determines a condition in which window glass is easily fogged during heating in winter and automatically sets a foot defroster mode to prevent fogging of window glass. It concerns the device.

[0002]

2. Description of the Related Art Conventionally, an air conditioner for a vehicle of an automatic control type usually starts heating in a vehicle compartment in a foot mode when heating is started in winter. At this time, in the foot mode, a large part (for example, about 70 to 80%) of the amount of air blown into the vehicle compartment is blown out from the foot opening toward the occupant's feet, and the remaining small amount of air is directed from the defroster opening toward the inside of the window glass. Just blow it out.

[0003] Therefore, in cold weather when the outside air temperature is 0 ° C or less, a small amount of air (warm air) flows from the defroster opening.
If only the air blows out, the temperature of the window glass does not rise sufficiently, and fogging is likely to occur on the inner surface of the window glass. Therefore, when fogging occurs on the inner surface of the window glass, the occupant switches the blowing mode to the foot defroster mode or the defroster mode by manual operation, and removes the fogging of the window glass.

As described above, every time the window glass becomes fogged, the occupant needs to manually set the foot defroster mode or the defroster mode, and the manual operation becomes cumbersome.

[0005] Japanese Patent No. 2680391 discloses that
As a differential foot mode in which air is blown out from the foot opening toward the occupant's feet and air is also blown from the defroster opening toward the inner surface of the window glass, a first differential foot mode in which the amount of air blown out by the defroster is small (corresponding to the foot mode of the present invention) ) And a second differential foot mode (corresponding to the foot defroster mode of the present invention) in which the amount of air blown out by the defroster is larger than the first differential foot mode, and the window is set by setting the second differential foot mode when the outside air temperature is low. The first differential foot is used to prevent fogging of the glass and utilize the fact that the air volume increases in conjunction with an increase in the target outlet temperature when the target outlet temperature of the air blown into the vehicle interior is equal to or higher than a predetermined value. Air conditioner for vehicles aimed at simultaneously satisfying both prevention of fogging of window glass and improvement of heating performance inside the vehicle by switching to the mode It has been described.

According to this, since the first differential foot mode and the second differential foot mode are automatically switched based on the target outlet temperature and the outside air temperature, the trouble of the occupant manually switching the outlet mode is eliminated. it can.

[0007]

However, when the antifogging property of the window glass was actually evaluated under various use environments of the air conditioner with respect to the prior art disclosed in the above publication, it was found that only the conditions of the target blowing temperature and the outside air temperature were used. It has been found that, when switching between the foot mode (first differential foot mode) and the foot defroster mode (second differential foot mode), the antifogging property cannot be sufficiently secured in practical use.

[0008] That is, the occurrence of fogging of the window glass depends on the temperature of the window glass and the humidity in the vehicle interior, and the temperature of the window glass is actually greatly affected by the vehicle speed, the amount of solar radiation and the like. In particular, at a high vehicle speed, the window glass is cooled by the vehicle wind blowing strongly against the window glass, and the temperature of the window glass is lowered, so that fogging is likely to occur. Further, since the window glass has a large heat capacity, the temperature of the window glass greatly changes depending on the amount of solar radiation.

However, according to the prior art, the vehicle speed,
Since the switching between the foot mode and the foot defroster mode is performed irrespective of conditions such as the amount of solar radiation, it is not possible to ensure sufficient anti-fog properties at high vehicle speeds, low solar radiation, and the like.

Further, if the setting area of the foot defroster mode is simply enlarged with respect to the change of the target blowing temperature and the outside air temperature in order to secure the anti-fogging property, the setting area of the foot mode becomes narrow, and the interior of the vehicle interior is reduced. Heating performance is impaired.

In view of the above, the present invention determines the switching timing of the air conditioner for the vehicle to the foot defroster mode appropriately, thereby ensuring the anti-fog properties of the window glass and the heating performance of the vehicle interior. The aim is to improve the compatibility with.

[0012]

In order to achieve the above object, according to the first aspect of the present invention, a foot opening (17) is provided.
And a foot mode in which a small amount of air is blown out from the defroster opening (15), and the amount of air blown out from the foot opening (17) is reduced as compared with the foot mode. In a vehicle air conditioner that can at least set a foot defroster mode for increasing the amount of air blown out, a foot mode is selected when a target air temperature (TAO) of air blown into the vehicle compartment is equal to or higher than a predetermined temperature, Even if the target outlet temperature (TAO) is equal to or higher than the predetermined temperature, when the target outlet temperature (TAO) is lower than the target outlet temperature fogging limit temperature determined by the vehicle speed and the outside air temperature, the foot mode is replaced with the foot defroster mode. Is selected, and the target blowing temperature fogging limit temperature is corrected to a higher temperature side by increasing the vehicle interior humidity.

[0013] According to this, in addition to the vehicle speed and the outside air temperature, which are highly correlated with the temperature of the window glass, the target blowing temperature fogging limit temperature can be accurately determined in consideration of the change in the vehicle interior humidity. When the target blowing temperature (TAO) is lower than the target blowing temperature fogging limit temperature, it is a fogging region of the window glass, and it is necessary to prevent fogging. In this case, the window glass is selected by selecting the foot defroster mode. The antifogging property of the can be surely secured.

On the other hand, when the target blowing temperature (TAO) is higher than the target blowing temperature fogging limit temperature, it is a clear area of the window glass and there is no need for anti-fogging. Heating performance in the cabin can be reliably ensured.

As described above, since the target blow-off temperature fogging limit temperature can be accurately determined, it is possible to achieve both the anti-fogging property of the window glass and the heating performance of the vehicle interior.

According to the second aspect of the present invention, the foot mode in which air is mainly blown out from the foot opening (17) and a small amount of air is blown out from the defroster opening (15) is compared with the foot mode. In a vehicle air conditioner which can at least set a foot defroster mode in which the amount of air blown out from (17) is reduced and the amount of air blown out from the defroster opening (15) can be set, the target of air blown into the vehicle compartment is set. When the blowing temperature (TAO) is equal to or higher than a predetermined temperature, the foot mode is selected and the target blowing temperature (T
Even if AO) is equal to or higher than the predetermined temperature, the target outlet temperature (TA)
When O) is lower than the target blowing temperature clouding limit temperature determined by the vehicle speed and the outside air temperature, the foot defroster mode is selected instead of the foot mode, and when a rainfall condition is determined, the target blowing temperature clouding limit is determined. It is characterized in that the temperature is corrected to a higher temperature side than when it is not raining.

Since there is a correlation that the vehicle interior humidity increases in a rainy state, the present invention focuses on this point, and corrects the target blowing temperature fogging limit temperature to a higher temperature side in a rainy state. By doing so, the same function and effect as the first aspect can be exhibited.

[0018] As in the third aspect of the present invention, the second aspect
In the above, if the rain state is determined based on the wiper operation signal of the vehicle, the rain state can be determined with a simple configuration using the existing wiper operation signal, which is very advantageous for cost reduction.

According to the fourth aspect of the present invention, a foot mode in which air is mainly blown out from the foot opening (17) and a small amount of air is blown out from the defroster opening (15) is compared with the foot mode. In a vehicle air conditioner which can at least set a foot defroster mode in which the amount of air blown out from (17) is reduced and the amount of air blown out from the defroster opening (15) can be set, the target of air blown into the vehicle compartment is set. When the blowing temperature (TAO) is equal to or higher than a predetermined temperature, the foot mode is selected and the target blowing temperature (T
Even if AO) is equal to or higher than the predetermined temperature, the target outlet temperature (TA)
If O) is lower than the target blowing temperature fogging limit temperature determined by the vehicle speed and the outside air temperature, the foot defroster mode is selected instead of the foot mode, and the target blowing temperature fogging limit temperature is set to the number of occupants in the vehicle cabin. It is characterized in that the temperature is corrected to the high temperature side by the increase.

Incidentally, there is a correlation that the humidity inside the vehicle increases due to an increase in the number of occupants in the vehicle interior.
By paying attention to this point, the target blowing temperature fogging limit temperature is corrected to a higher temperature side by increasing the number of occupants, whereby the same operational effects as those of the first and second aspects can be exhibited.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the correction amount of the target blowout temperature fogging limit temperature to the higher temperature side is increased as the outside air temperature is lower. .

According to this, the correction amount of the target blowing temperature fogging limit temperature to the high temperature side can be determined to an accurate value corresponding to the outside air temperature, and the target blowing temperature fogging limit temperature can be determined. Can be determined more accurately.

According to the sixth aspect of the present invention, the foot mode in which air is mainly blown out from the foot opening (17) and a small amount of air is blown out from the defroster opening (15) is compared with the foot mode. A program for automatically controlling an air conditioner for a vehicle, which is capable of at least setting a foot defroster mode in which an amount of air blown out from (17) is reduced and an amount of air blown out from a defroster opening (15) is increased. When the target outlet temperature (TAO) of the air blown into the vehicle compartment is equal to or higher than a predetermined temperature, the foot mode is selected. Even if the target outlet temperature (TAO) is equal to or higher than the predetermined temperature, the target outlet temperature (TAO) is If the target outlet temperature is lower than the cloudiness limit temperature determined by the vehicle speed and the outside air temperature, the foot defroster mode is selected instead of the foot mode, and the target The rise of the output temperature mist limit temperature cabin humidity and correcting to the high temperature side.

A sixth aspect of the present invention is directed to a program for automatically controlling an air conditioner for a vehicle, and has the same operational effects as the first aspect.

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

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 is an overall configuration diagram of a first embodiment of the present invention. An air conditioner case 2 of an air conditioner 1 is disposed inside a dashboard at a front portion of a vehicle interior. A passage for air flowing toward the vehicle interior is formed. An inside / outside air switching box 3 is provided at the upstream end of the air-conditioning case 2. The inside / outside air switching door 4 in the inside / outside air switching box 3 opens and closes the inside air intake port 5 and the outside air intake port 6, thereby providing the inside of the vehicle cabin. Air
Alternatively, air outside the vehicle compartment (outside air) is switched and introduced. A blower 7 is arranged downstream of the inside / outside air switching box 3, and a centrifugal blower fan 9 is housed in a case 8 of the blower 7, and the blower fan 9 is driven to rotate by a driving motor 10.

Next, an evaporator 11 is disposed downstream of the blower 7 as a heat exchanger for cooling. This evaporator 11
Is a compressor 4 driven by a vehicle engine (not shown)
The low-pressure refrigerant flowing into the evaporator 11 absorbs heat from the air blown from the blower 7 and evaporates, thereby cooling the blown air.

The compressor 40 is provided with an electromagnetic clutch 41 for interrupting power, and the power of the vehicle engine is transmitted through the electromagnetic clutch 41.

In the air conditioning case 2, a hot water heater core (heating heat exchanger) 12 for heating air using hot water (cooling water) of a vehicle engine as a heat source is disposed downstream of the evaporator 11. A bypass passage 13 is formed on the side of the hot water heater core 12, and the hot water heater core 1
2 bypasses the air.

An air mix door 14 composed of a plate door is rotatably disposed between the evaporator 11 and the heater core 12. The air mix door 14 is a temperature adjusting means, and adjusts the temperature of air blown into the vehicle interior by adjusting the ratio of the amount of hot air passing through the hot water heater core 12 and the amount of cold air passing through the bypass passage 13. The hot air from the hot water heater core 12 and the cold air from the bypass passage 13 are mixed on the downstream side of the hot water heater core 12 to produce air at a desired temperature.

Further, a defroster opening 15, a face opening 16, and a foot opening 17, which constitute a blowing mode switching unit, are opened at the downstream end of the air conditioning case 2. The defroster opening 15 blows air to the inside of the vehicle windshield through a defroster duct (not shown), and is opened and closed by a rotatable plate-like defroster door 15a.

The face opening 16 blows air toward the upper body of the occupant of the vehicle through a face duct (not shown).
It is opened and closed by a. The foot opening 17 blows air toward the feet of the occupant in the vehicle cabin through a foot duct (not shown).
It is opened and closed by a.

The above-mentioned blow mode doors 15a, 16a,
17a is connected to a common link mechanism 18, and through this link mechanism 18, the electric drive 1 comprising a servomotor is connected.
9 driven. The inside / outside air switching door 4 and the air mixing door 14 are also driven by electric drive devices 20 and 21 each including a servomotor.

In the present embodiment, a face mode in which the face opening 16 is fully opened by opening and closing the blowing mode doors 15a, 16a, 17a and air is blown from the face opening 16 toward the upper body of the occupant in the vehicle. A bi-level mode in which both the face opening 16 and the foot opening 17 are opened to blow air toward the upper body and feet of the passenger in the cabin, the foot opening 17 is fully opened, and the defroster opening 15 is slightly opened. Air is mainly blown out from the foot opening 17 and the defroster opening 1
By opening the defroster opening 15 and the foot opening 17 to the same extent in the foot mode in which a small amount of air is blown out of the foot opening 5, the foot opening 17 in comparison with the foot mode is opened.
A defroster mode in which the amount of air blown out of the vehicle is reduced and the amount of air blown out of the defroster opening 15 is increased, and a defroster mode in which the defroster opening 15 is fully opened and air is blown from the defroster opening 15 to the inner surface of the vehicle windshield. It can be set.

Next, an outline of the electric control unit according to the present embodiment will be described.
It is composed of a well-known microcomputer such as an OM and a RAM, and its peripheral circuits. The air-conditioning electronic control device 22 has a hot water temperature T for air-conditioning control.
w, the inside air temperature Tr, the outside air temperature Tam, the amount of solar radiation Ts, the evaporator outlet temperature Te as the evaporator cooling degree, the actual opening degree θ of the air mix door 14, the vehicle speed SPD, the vehicle interior humidity (relative humidity) RH, and the like. A detection signal is input from each of the sensor groups 23 to 29 and 43 to be detected.

The humidity sensor 43 is installed at an appropriate location in the vehicle compartment, and its electrical characteristics (capacity, resistance, etc.) change in accordance with the relative humidity RH in the vehicle compartment, and output an electric signal corresponding to the relative humidity RH. What happens. The humidity sensor 43 is preferably installed at the same location as the inside air sensor 24 (for example, at the periphery of the instrument panel at the front of the vehicle compartment). In this way, both the vehicle interior relative humidity RH and the vehicle interior temperature (internal temperature) Tr at the installation site of the humidity sensor 43 can be detected, and the absolute humidity in the vehicle interior is calculated from both the detection signals RH and Tr. be able to. Therefore, air-conditioning control in consideration of the absolute humidity in the vehicle compartment is also possible.

The air-conditioning operation panel 30 arranged around the instrument panel in the passenger compartment is provided with the following operation members manually operated by an occupant. The operation signals of these operation members are also transmitted to the air-conditioning electronic control unit 22. Is entered.

The operating members of the air-conditioning operation panel 30 include:
A temperature setting unit 31 for generating a temperature setting signal Tset, an air volume switch 32 for generating an air volume switching signal for the blower 7, an inside / outside air switching switch 33 for generating an inside / outside air switching signal, a blowing mode switch 34 for generating a blowing mode signal, and refrigeration An air conditioner switch 35 for generating an on / off signal of an electromagnetic clutch 41 for the compressor 40 of the cycle, an auto switch 36 for setting an automatic control mode of air conditioning, and the like are provided.

In this embodiment, the blow mode switch 34 is provided with a switch for manually setting each mode of face, bi-level, foot, and foot defroster, and a defroster switch dedicated to the defroster mode.

The applied voltage of the fan drive motor 10 of the blower 7 is controlled by a drive circuit 37, and the rotation speed of the blower 7 is adjusted by controlling the motor applied voltage. Also,
The power supply to the electromagnetic clutch 41 of the compressor 40 is interrupted by the drive circuit 38. The air conditioning electronic control unit 22 includes:
Power is supplied from a vehicle-mounted battery 42 via an ignition switch 39 of the vehicle engine.

Next, the operation of this embodiment in the above configuration will be described. The flowchart of FIG. 2 shows the outline of the control processing executed by the microcomputer of the air-conditioning electronic control device 22. The control routine of FIG. 2 is performed when the ignition switch 39 of the vehicle engine is turned on and the control device 2 is turned on.
When the power is supplied to the air conditioning operation panel 3,
It starts when the 0 auto switch 36 is turned on.

First, in step S100, flags, timers and the like are initialized, and in the next step S110, detection signals from the sensor groups 23 to 29 and 43, operation signals from the operation members 31 to 36 of the panel 30, and the like are transmitted. Read.

Subsequently, in step S120, a target blowing temperature TAO of the conditioned air blown into the vehicle compartment is calculated based on the following equation (1). The target outlet temperature TAO is an outlet temperature required to maintain the vehicle interior at the set temperature Tset of the temperature setting switch 37a.

[0044]

## EQU1 ## TAO = Kset × Tset−Kr × Tr−Kam ×
Tam−Ks × Ts + C where, Tr: internal temperature detected by the internal air sensor 24 Tam: external temperature detected by the external air sensor 25 Ts: solar radiation detected by the solar radiation sensor 26 Kset, Kr, Kam, Ks: control Gain C: Correction Constant Next, in step S130, the target opening degree SW of the air mix door 14 is calculated based on the following equation (2).

[0045]

## EQU2 ## SW = {(TAO-Te) / (Tw-Te)}
× 100 (%) where, Te: the evaporator outlet temperature detected by the evaporator temperature sensor 27 Tw: the heater core hot water temperature detected by the water temperature sensor 23 Next, in step S140, the air blown by the blowing fan 9 The target air volume BLW is calculated based on the TAO. The target airflow BLW is calculated based on the maps shown in FIGS. That is, FIG.
4 is a map of basic control for determining a target air flow BLW based on the O. The target air flow is increased on the high temperature side (maximum heating side) and the low temperature side (maximum cooling side) of the TAO,
The target air volume is reduced in the intermediate temperature range.

On the other hand, FIG. 3B is a map of the warm-up control for preventing the cold air from blowing into the vehicle interior due to the low heater core hot water temperature Tw at the time of the winter heating start. First predetermined temperature T
When the temperature is lower than w1 (for example, 30 ° C.), the power supply to the fan drive motor 10 of the blower 7 is cut off to stop the blower 7, and the heater core hot water temperature Tw becomes the first predetermined temperature T
When w1 is exceeded, the blower 7 is started with the minimum airflow Lo.

The heater core hot water temperature Tw is equal to the first predetermined temperature T
When the temperature rises from w1 to a second predetermined temperature Tw2 (for example, 60 ° C.), the voltage applied to the fan drive motor 13 of the blower 7 is increased in conjunction therewith, thereby reducing the airflow of the blower 7 to the minimum airflow Lo. To the maximum air flow Hi. When the water temperature Tw becomes higher than the second predetermined temperature Tw2, the warm-up control ends, and a transition is made to a steady state in which the target air volume is determined based on the map of FIG.

Next, in step S150, the inside / outside air mode is determined according to the TAO. As is well known, as the TAO rises from the low temperature side to the high temperature side, the inside / outside air mode is changed to the whole inside air mode → the inside / outside air mixing mode → the whole outside air mode,
Alternatively, the setting is switched from the all inside air mode to the all outside air mode.

Next, in step S160, the blowing mode is determined according to the TAO. As shown in the map of FIG. 4, this blowing mode switches and sets the face (FACE) mode → the bi-level (B / L) mode → the foot (FOOT) mode as the TAO rises from the low temperature side to the high temperature side.

It should be noted that the face mode and the bi-level are final decisions, whereas the foot mode is a temporary decision, and the final decision of the foot mode is made in step S180. Therefore, if the foot mode is temporarily determined in step S160, the next step S1
From step 70, the process proceeds to step S180 to select a foot mode or a foot defroster (F / D) mode. Details of the mode selection in step S180 will be described later with reference to FIG.

The mode switching temperatures B1 and B2 in FIG. 4 are, for example, about 25 to 29 ° C., and the mode switching temperatures B3 and B4 are, for example, about 40 ° C.

Next, in step S190, the intermittent operation (ON-OFF) of the compressor operation is determined. The intermittent operation of the compressor depends on the target evaporator outlet temperature TEO and the actual evaporator outlet temperature Te.
Is determined by comparing with. That is, the evaporator outlet temperature Te
Is lower than the target evaporator outlet temperature TEO, the compressor 4
0 is turned off (OFF), and conversely, the evaporator outlet temperature T
When e rises above the target evaporator outlet temperature TEO, the compressor 40 is turned on (ON).

Next, in step S200, the various control values calculated in steps S130 to S190 are applied to the electric drives 19, 20, 21 and the drive circuits 37, 38.
To perform air conditioning control. That is, the inside / outside air switching electric drive device 20 controls the operation position of the inside / outside air switching door 4 so as to obtain the inside / outside air mode in step S150.
Further, the electric drive device 19 for the blow-out mode is operated in step S16.
The operation positions of the blowout mode doors 15a, 16a, and 17a are controlled so that the blowout modes of 0 and S180 are obtained.

The air mixing electric drive device 21 also controls the air mixing door 14 so that the actual air mixing door opening θ detected by the air mixing door opening sensor 28 matches the target opening SW in step S130. Control the opening degree. The rotation speed of the blower fan driving motor 10 is controlled by controlling the applied voltage so as to obtain the target air flow amount BLW in step S140. Further, the electromagnetic clutch 41 turns on and off the operation of the compressor 40 so that the actual evaporator outlet temperature Te becomes the target evaporator outlet temperature TEO.
Control.

Next, the foot (FO) which is a feature of the present invention is described.
The selection (automatic switching) of the OT) mode and the foot defroster (F / D) mode will be described in detail with reference to FIG. In the present embodiment, as shown in the map of FIG. 4, if the TAO is in the high-temperature side region exceeding the mode switching temperature B3, the foot mode is temporarily determined. Then, the process proceeds from step S170 in FIG. 2 to step S1810 in FIG. 5, and it is first determined whether or not warm-up is being performed.

Here, the warm-up is, as described above with reference to FIG. 3B, when the control for restricting the air volume of the blower 7 is performed when the heater core hot water temperature Tw is low. Is specifically determined as shown in FIG.
As shown in FIG. 5, when the water temperature Tw is lower than the third predetermined temperature Tw3, it is determined that warm-up is being performed, and when the water temperature Tw is higher than the fourth predetermined temperature Tw4, the warm-up control is terminated and a transition to a steady state is made. judge.

The fourth predetermined temperature Tw4 is a temperature corresponding to the second predetermined temperature Tw2 (for example, 60 ° C.) in FIG. 3B, and the third predetermined temperature Tw3 is slightly lower than the fourth predetermined temperature Tw4. Temperature.

In the steady state, the determination in step S1810 is N
The result is O, and the process proceeds to step S1820 to determine whether the vehicle speed is equal to or higher than a predetermined value. Specifically, as shown in FIG. 6B, this determination is made equal to or more than a predetermined value when the vehicle speed is higher than the second predetermined value SP2 (YES), and is equal to or less than the predetermined value when the vehicle speed is lower than the first predetermined value SP1. (NO). Note that the second predetermined value S
P2 is, for example, a vehicle speed of about 30 km / h, and the first predetermined value SP1 is, for example, a vehicle speed of about 20 km / h.

If the vehicle speed is higher than the predetermined value, step S18
Proceed to 30 to determine if TAO is below the fogging threshold temperature. This determination is specifically made based on the cloudy diagram illustrated in FIG. The fogging diagram in FIG. 7 was created only after the inventor repeated various experimental studies such as actual vehicle tests, and determined the fogging limit temperature of TAO using the outside air temperature, the vehicle speed, and the cabin humidity as parameters. is there.

In the map shown in FIG. 3 (a), the side where TAO is higher than the predetermined temperature T1 is the set range of the foot mode. When TAO becomes higher than the predetermined temperature T1 in a steady state, the air volume into the vehicle interior increases, and the window increases. Since the glass temperature is raised, the anti-fog performance of the window glass can be improved. On the other hand, the higher the vehicle speed, the lower the window glass temperature, so that it acts in the direction of expanding the cloudy region. Therefore, T determined by the vehicle speed
As shown in FIG. 7, the fogging limit temperature of the AO becomes higher as the vehicle speed becomes higher. In addition, the lower the outside air temperature, the lower the temperature of the window glass and the more the cloudy area. Therefore, the fogging limit temperature of the TAO determined by the vehicle speed increases as the outside air temperature decreases.

As described above, the cloudiness limit temperature of TAO determined by the vehicle speed and the outside air temperature is corrected so that the cloudiness limit temperature becomes higher as the vehicle interior humidity further increases. In FIG. 7, the broken line indicates the fogging limit temperature when the vehicle interior humidity is 40% (reference humidity), and the solid line indicates the vehicle interior humidity = 20%.
(Low humidity) is the fogging limit temperature, and the dashed line is the fogging limit temperature when the vehicle interior humidity is 60% (high humidity).

The difference (correction amount) between the fogging limit temperature at 20% (low humidity) and the fogging limit temperature at 40% (reference humidity), and the fog limit temperature at 40% (reference humidity) and 60%
The difference (correction amount) from the fogging limit temperature at% (high humidity) is set to increase as the outside air temperature decreases.

In FIG. 7, the area lower than the fogging limit temperature of the TAO determined by the vehicle speed, the outside air temperature, and the humidity in the cabin is the fogging area of the window glass of the TAO, and the area on the high temperature side is the fogging area of the window glass of the TAO. Become. In this way, by determining the fogging limit temperature of the TAO in consideration of the change in the vehicle interior humidity with respect to the change in the vehicle speed and the outside air temperature, it is possible to more accurately determine the window glass fogging area and the window glass clear area. It can be carried out.

In step S1830, it is determined whether TAO is lower than the fogging limit temperature in FIG.
If AO is lower than the fogging limit temperature, then step S18
At 40, it is determined whether the outside air temperature is low. Specifically, this determination is made as shown in FIG. 6C, when the outside air temperature Tam becomes the first predetermined temperature Ta.
m1 (for example, -1 ° C.), the low outside air temperature (YE
S), when the outside air temperature Tam is higher than the second predetermined temperature Tam2 (for example, 0 ° C.), it is determined that the outside air temperature is not low (NO).

If it is a low outside temperature, then step S18
At 50, it is determined whether the solar radiation is low. Specifically, as shown in FIG. 6D, when the amount of solar radiation Ts is smaller than the first predetermined value Ts1, it is determined that the amount of solar radiation is low (YES), and when the amount of solar radiation Ts is larger than the second predetermined value Ts2, Not low solar radiation (N
O). The second predetermined value Ts2 is, for example, 5K
cal / m ² · min, the first predetermined value Ts
1 is a value slightly smaller than this.

If the amount of solar radiation is low, step S1860
To select the foot defroster mode. That is, in a steady state after the end of the warm-up control,
That the vehicle speed is equal to or higher than a predetermined value (step S1820);
TAO is lower than the fogging limit temperature in the fogging diagram of FIG. 7 (step S1830), low outside air temperature (step S1840), and low solar radiation (step S1840).
When all of the conditions of 1850) are satisfied, it is estimated that fogging of the window glass is likely to occur, and the foot defroster mode is automatically selected.

As a result, the amount of air blown from the defroster can be increased more than in the foot mode, and the antifogging property of the window glass can be ensured. Moreover, since there is no need for the occupant to perform a manual operation for setting the foot defroster mode, the complexity of the manual operation can be eliminated.

On the other hand, if any one of the above conditions does not apply, the flow advances to step S1870 to select the foot mode. Therefore, the foot mode is always set except when the window glass is liable to be clouded. Can be set, which is advantageous for securing the vehicle interior heating performance in cold weather.

In the steady state described above, TAO is lower than the fogging limit temperature in the fogging diagram of FIG.
This is lower than the predetermined temperature a or b (b = a + α) in (e), and this predetermined temperature a can be obtained by equation (1) in FIG. Then, X and Y in the equation (1)
Can be determined based on the vehicle speed by the maps of FIGS. 6F and 6G, respectively, and Z of the equation (1) can be determined based on the vehicle interior humidity RH by the map of FIG. 6H.

On the other hand, if it is determined in step S1810 that warm-up is being performed, step S1840 is performed.
Then, it is determined whether the outside air temperature is low as in the example of FIG. If the outside air temperature is low, the process advances to step S1850 to determine whether the amount of solar radiation is low as in the example of FIG.

If the amount of solar radiation is low, step S1860
To select the foot defroster mode. In other words, at the time of warm-up, when it is satisfied that the outside air temperature is low (step S1840) and the amount of solar radiation is low (step S1850), it is estimated that fogging of the window glass is likely to occur. Automatically select the foot defroster mode.

This is for the following reason. That is, at the time of warm-up, since the heater core hot water temperature Tw is low in the first place, the inside temperature of the vehicle interior becomes low, and the temperature in FIG.
The warm-up control of the vehicle causes the amount of air blown out of the vehicle interior to decrease. The overlapping of these two adverse conditions creates a situation in which fogging of the window glass is likely to occur during warm-up. Therefore, when warming up,
The foot defroster mode is selected by estimating a situation in which fogging of the window glass is likely to occur only when the condition (1) is satisfied.
That is, even if the vehicle speed is low or the TAO is high temperature, the foot defroster mode is immediately selected according to the above-mentioned conditions regardless of these. This makes it possible to automatically secure the anti-fogging property at the time of warm-up and eliminate the complexity of manual operation.

If any one of the above conditions is not satisfied, the process proceeds to step S1870, and the foot mode is selected, so that even when warming up, the performance of the vehicle interior heating performance can be prioritized.

(Second Embodiment) In the first embodiment described above, the humidity RH is detected by the humidity sensor 43 and the fogging limit temperature of the TAO is corrected to a higher temperature by increasing the humidity RH. In the second embodiment, the same foot defroster mode switching control as in the first embodiment is performed without detecting the vehicle interior humidity RH.

That is, since there is a correlation that the vehicle interior humidity RH increases during rainfall, the second embodiment focuses on this point, and sets the fog limit temperature of the TAO to a higher temperature side during rainfall than during non-rainfall. It is to be corrected. Since the vehicle wiper device operates during rainfall, the rainfall state is determined based on the operation signal of the vehicle wiper device, and the fogging limit temperature of the TAO is corrected to a higher temperature side.

In this way, when the window glass is easily fogged by rain, the fog limit temperature of the TAO is corrected to the high temperature side, so that the setting area of the foot defroster mode is expanded to the high temperature side of the TAO as compared with the non-rainfall time. Fogging performance can be improved. On the other hand, in the non-rainfall time, by correcting the cloudiness limit temperature of the TAO to a lower temperature side than in the rainy time, the setting area of the foot defroster mode is limited to a narrow area on the low-temperature side. Troubles such as a burning sensation due to the hot air blowing can be suppressed.

In the second embodiment, it is a matter of course that a sensor for detecting the rain state may be provided to determine the rain state. As a sensor for detecting a rainfall state, various sensors such as an optical system known for use as an automatic control device of a vehicle wiper device can be used.

(Third Embodiment) In the first embodiment, the humidity RH is detected by the humidity sensor 43 and the fogging limit temperature of the TAO is corrected to a higher temperature side by increasing the humidity RH. In the third embodiment, similar to the second embodiment, the same foot defroster mode switching control as in the first embodiment is performed without detecting the vehicle interior humidity RH.

That is, when the number of passengers in the vehicle interior increases,
Since there is a correlation that the vehicle interior humidity RH increases,
Focusing on this point, the third embodiment corrects the target blowout temperature fogging limit temperature to a higher temperature side by increasing the number of passengers in the vehicle cabin.

In the third embodiment, the number of occupants in the vehicle interior is determined by a seat switch (not shown) for each seat in the vehicle interior.
Can be detected. As another means, an infrared sensor for detecting the presence or absence of an occupant in each seat in the vehicle compartment may be provided, and the number of passengers in the vehicle compartment may be determined based on a detection signal of the infrared sensor.

[Brief description of the drawings]

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

FIG. 2 is a flowchart showing an outline of the operation of the first embodiment of the present invention.

FIG. 3 is an air volume control characteristic diagram according to the first embodiment of the present invention.

FIG. 4 is a blowing mode switching characteristic diagram according to the first embodiment of the present invention.

FIG. 5 is a flowchart showing an operation of a main part of the first embodiment of the present invention.

FIG. 6 is an operation explanatory view of the first embodiment of the present invention.

FIG. 7 is a fogging diagram showing a fogging limit temperature of TAO in the first embodiment of the present invention.

[Explanation of symbols]

7 blower, 12 heat exchanger for heating, 15 defroster opening, 17 foot opening, 22 electronic control unit for air conditioning.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) B60H 1/08 621 B60H 1/08 621Z

Claims (6)

[Claims] 1. A blower (7) for blowing air toward a vehicle interior, a heating heat exchanger (12) for heating air blown by the blower (7), and a heating heat exchanger (12). A defroster opening (15) for blowing out the air heated by the vehicle toward the vehicle window glass, and a foot opening (17) for blowing out the air heated by the heating heat exchanger (12) to the feet of the occupant in the vehicle compartment. A foot mode in which air is mainly blown out from the foot opening (17) and a small amount of air is blown out from the defroster opening (15); and the foot opening (17) as compared with the foot mode.
To reduce the amount of air blown out of the defroster opening (1).
5) at least a foot defroster mode for increasing the amount of air blown out from the vehicle can be set. When the target blowout temperature (TAO) of air blown into the vehicle compartment is equal to or higher than a predetermined temperature, the foot mode is selected. Even if the target outlet temperature (TAO) is equal to or higher than the predetermined temperature, when the target outlet temperature (TAO) is lower than the target outlet temperature fogging limit temperature determined by the vehicle speed and the outside air temperature, the above-mentioned foot mode is replaced. An air conditioner for a vehicle, wherein the foot defroster mode is selected, and the target blowout temperature fogging limit temperature is corrected to a higher temperature side by increasing the humidity in the vehicle interior. 2. A blower (7) for blowing air toward a vehicle interior, a heating heat exchanger (12) for heating air blown by the blower (7), and a heating heat exchanger (12). A defroster opening (15) for blowing out the air heated by the vehicle toward the vehicle window glass, and a foot opening (17) for blowing out the air heated by the heating heat exchanger (12) to the feet of the occupant in the vehicle compartment. A foot mode in which air is mainly blown out from the foot opening (17) and a small amount of air is blown out from the defroster opening (15); and the foot opening (17) as compared with the foot mode.
To reduce the amount of air blown out of the defroster opening (1).
5) at least a foot defroster mode for increasing the amount of air blown out from the vehicle can be set. When the target blowout temperature (TAO) of air blown into the vehicle compartment is equal to or higher than a predetermined temperature, the foot mode is selected. Even if the target outlet temperature (TAO) is equal to or higher than the predetermined temperature, when the target outlet temperature (TAO) is lower than the target outlet temperature fogging limit temperature determined by the vehicle speed and the outside air temperature, the above-mentioned foot mode is replaced. An air conditioner for a vehicle, wherein the foot defroster mode is selected, and when a rainfall condition is determined, the target blowing temperature fogging limit temperature is corrected to a higher temperature side than when the rainfall condition is not present. 3. The vehicle air conditioner according to claim 2, wherein the rain state is determined based on a wiper operation signal of the vehicle. 4. A blower (7) for blowing air toward a vehicle interior, a heating heat exchanger (12) for heating air blown by the blower (7), and a heating heat exchanger (12). A defroster opening (15) for blowing out the air heated by the vehicle toward the vehicle window glass, and a foot opening (17) for blowing out the air heated by the heating heat exchanger (12) to the feet of the occupant in the vehicle compartment. A foot mode in which air is mainly blown out from the foot opening (17) and a small amount of air is blown out from the defroster opening (15); and the foot opening (17) as compared with the foot mode.
To reduce the amount of air blown out of the defroster opening (1).
5) at least a foot defroster mode for increasing the amount of air blown out from the vehicle can be set. When the target blowout temperature (TAO) of air blown into the vehicle compartment is equal to or higher than a predetermined temperature, the foot mode is selected. Even if the target outlet temperature (TAO) is equal to or higher than the predetermined temperature, when the target outlet temperature (TAO) is lower than the target outlet temperature fogging limit temperature determined by the vehicle speed and the outside air temperature, the above-mentioned foot mode is replaced. The vehicle air conditioner, wherein the foot defroster mode is selected, and the target blowing temperature fogging limit temperature is corrected to a higher temperature side by increasing the number of occupants in the vehicle cabin. 5. The air conditioner for a vehicle according to claim 1, wherein the correction amount of the target blowout temperature fogging limit temperature to the higher temperature side is increased as the outside air temperature is lower. 6. A blower (7) for blowing air toward a vehicle interior, a heating heat exchanger (12) for heating the air blown by the blower (7), and a heating heat exchanger (12). A defroster opening (15) for blowing out the air heated by the vehicle toward the vehicle window glass, and a foot opening (17) for blowing out the air heated by the heating heat exchanger (12) to the feet of the occupant in the vehicle compartment. A foot mode in which air is mainly blown out from the foot opening (17) and a small amount of air is blown out from the defroster opening (15); and the foot opening (17) as compared with the foot mode.
To reduce the amount of air blown out of the defroster opening (1).
5) A program for automatically controlling a vehicle air conditioner capable of at least setting a foot defroster mode for increasing an amount of air blown out from the air conditioner, wherein a target air temperature (TAO) of air blown into the vehicle compartment is determined. When the temperature is equal to or higher than a predetermined temperature, the foot mode is selected. Even when the target air temperature (TAO) is equal to or higher than the predetermined temperature, the target air temperature (TAO) is determined by a vehicle speed and an outside air temperature. When the temperature is lower than the fogging limit temperature, the foot defroster mode is selected in place of the foot mode, and the target blowing temperature fogging limit temperature is corrected to a higher temperature side by increasing the vehicle interior humidity. Air conditioning program.