JPH07285320A - Failure judging device for humidity sensor and air conditioner for vehicle - Google Patents

Abstract

PURPOSE:To detect a failure due to the open circuit or short circuit of a humidity sensor and a failure due to the characteristic deterioration, and conduct air conditioning control for defogging and power saving at the time of the failure. CONSTITUTION:An inside/outside air switching damper 20 switches inside air circulation and outside air introduction. The compressor 26 of a refrigerating cycle 14 is controlled by a control device 16. A humidity sensor 51 detects the humidity in a car room and outputs it to the control device 16. The control device 16 receives and compares the detection signal of the humidity sensor 51 when the compressor 26 is turned on and after a prescribed period elapses, and it detects a failure due to the characteristic deterioration of the humidity sensor 51 based on whether the detection signal is changed when the humidity in the car room is changed after the dehumidifying operation is started. The humidity condition for turning the compressor 26 on is set in the inside air circulation mode at the time of the failure, and the humidity condition for stopping the compressor 26 is set in the outside air introduction mode for defogging and power saving.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a failure determination device for a humidity sensor for detecting indoor humidity and an air conditioner for controlling dehumidifying means according to the humidity detected by the humidity sensor.

[0002]

2. Description of the Related Art For example, in an automobile air conditioner,
Some include a humidity sensor for detecting the humidity in the vehicle compartment, and the air conditioning operation is controlled according to the humidity detected by the humidity sensor. As a result, the humidity inside the passenger compartment is controlled by controlling the humidity inside the passenger compartment within a certain range to provide passengers with a comfortable passenger compartment space, or by introducing dehumidified air into the passenger compartment when the outside air temperature is low. The air conditioning control is performed such that the temperature is controlled to be equal to or lower than a predetermined value to prevent the occurrence of fogging in the window.

In this case, as the above-mentioned humidity sensor, for example, as schematically shown in FIG. 13, the humidity sensor 4 is formed by sandwiching a polymer film 1 as a dielectric between a pair of electrode plates 2 and 3. Is common. In this case, when the polymer film 1 absorbs moisture in the air according to the humidity, impedance such as resistance value or capacitance value changes according to the degree of absorption, so that the impedance is changed to the electrode plates 2, 3
It is possible to obtain a detection output according to the humidity by electrically detecting through the.

[0004]

When the humidity sensor 4 fails, the humidity inside the vehicle compartment cannot be controlled. For example, when a wire break or a short circuit occurs, the humidity detected by the humidity sensor 4 is detected. Is 0% or 100%
Therefore, there is a problem in that the air conditioning control based on this also shifts to an extreme direction.
Therefore, conventionally, the humidity detected by the humidity sensor 4 is 0%.
Alternatively, in the case of showing an extreme value such as 100%, it is considered that the humidity sensor 4 is judged to be out of order on the air conditioning control device side and the air conditioning control based on the humidity detected by the humidity sensor 4 is stopped. .

However, unlike the general sensor, the humidity sensor 4 has a unique characteristic variation failure mode in which the detection output with respect to humidity varies in addition to the failure mode as described above. This is because the impedance characteristics fluctuate due to dust or chemicals adhering to the side surface of the polymer film 1 forming the humidity sensor 4,
Alternatively, the impedance characteristic fluctuates due to aging, which causes a problem that the correlation between the actual humidity and the impedance value of the humidity sensor 1 deviates.

In such a failure mode, for example, FIG.
As shown in Fig. 4, the impedance characteristic with respect to humidity tends to partially become a constant value as indicated by the broken line in the figure in contrast to the impedance characteristic in the normal state shown by the solid line (high in the figure An example is shown in which the humidity is constant in the humidity range.) As a whole, the detection characteristics are such that the detected humidity shifts to the higher side, and also changes to 100% saturation in the high humidity range.

In such a failure mode occurrence state, the sensor output does not have a value indicating an extreme detected humidity such as 0% or 100%, so that the failure state can be determined by the conventional configuration. As a result, if air conditioning control is performed based on the detection output from the humidity sensor 4,
Due to the difference between the actual humidity and the detected humidity, there is a problem that the air conditioning control in the vehicle compartment cannot be performed properly.

The present invention has been made in view of the above circumstances, and an object thereof is to be able to determine a failure mode due to aged deterioration of a humidity sensor, and to cope with this when a failure state is detected. Another object of the present invention is to provide a failure determination device for a humidity sensor and a vehicle air conditioner capable of estimating the humidity in the vehicle compartment and performing appropriate air conditioning control.

[0009]

A failure determination device for a humidity sensor according to the present invention is intended for a humidity sensor for detecting humidity in a room, the humidity of which is controlled by the operation of the dehumidifying means. The present invention is characterized in that a judgment means for judging a failure of the humidity sensor based on a change in the detection output of the humidity sensor at that time is provided on condition that the operation is switched on and off.

It is preferable that the determination means is configured to determine the failure of the humidity sensor by comparing the detection output of the humidity sensor after the dehumidifying means is switched on and off and after a lapse of a predetermined time from the switching time.

Further, it is preferable that the determining means is configured to determine the failure of the humidity sensor with reference to an on / off switching time point at which the dehumidifying means is switched from an off state to an on state.

The air conditioner for a vehicle according to the present invention comprises an air blowing means for blowing air into the vehicle compartment, an inside air / outside air switching means capable of switching the air blown by the air blowing means to either the inside air circulation or the outside air introduction, and the vehicle interior. The humidity sensor for detecting the humidity of the vehicle and the dehumidifying means for dehumidifying the vehicle interior based on the detection output of the humidity sensor, and the failure sensor of the humidity sensor according to claim 1, further comprising the humidity sensor. When a failure of the humidity sensor is determined by the determination means in the failure determination device, a control means is provided for controlling the dehumidifying means by setting a predetermined humidity condition according to the setting state of the inside / outside air switching means. It has a feature in that it is configured.

Further, instead of the humidity sensor failure determination device in the above configuration, a humidity sensor failure determination device according to claim 2 or 3 may be provided.

[0014]

According to the failure determination device of the humidity sensor according to the first aspect of the present invention, the humidity in the room changes when the dehumidifying means is switched on and off. Therefore, when the humidity sensor is operating normally, the detected humidity is detected. Therefore, it is possible to determine whether or not the humidity sensor is operating normally or is out of order by detecting the indoor humidity from the detection output of the humidity sensor at that time by the determination means. As a result, it becomes possible to determine the failure state in response to not only short-circuit failure or disconnection failure of the humidity sensor but also characteristic variation due to deterioration.

According to another aspect of the present invention, there is provided a humidity sensor failure determining device, wherein the determining means determines the humidity sensor failure determining operation.
Since the failure of the humidity sensor is determined by comparing the detection output of the humidity sensor at the time of switching the operation of the dehumidifying means with the detection output of the humidity sensor after the elapse of a predetermined time, it is necessary to switch the operation of the dehumidifying means on and off. It is possible to reliably perform the failure determination operation of the humidity sensor under a certain condition in response to the accompanying change in indoor humidity.

According to another aspect of the present invention, there is provided a humidity sensor failure determination device, wherein the determination means determines the humidity sensor failure determination operation.
Since the operation of the dehumidifying means is performed based on the time point when the dehumidifying means is switched from the off state to the on state, the humidity sensor is placed in a humidity controlled environment in which the humidity of the room is controlled by starting the operation of the dehumidifying means. Therefore, the failure determination of the humidity sensor can be performed quickly and reliably.

According to the air conditioner of the present invention, when the failure state of the humidity sensor is determined by the determination means of the failure determination device for each humidity sensor described above, the air conditioning control is performed based on the detection output of the humidity sensor. Therefore, the control means sets the predetermined humidity condition according to the setting state by the inside / outside air switching means at that time.

In this case, the set humidity condition is that the dehumidifying means operates based on the fact that it is expected that the window glass will fog when the inside / outside air switching means is set to the inside air circulation mode. When the humidity value is set to
The value of the humidity is set so that the dehumidifying means is not operated unnecessarily because the window glass is hardly fogged. As a result, even if the humidity sensor is out of order, it is possible to control the operation of the dehumidifying means in a manner that saves power while at the same time preventing fogging of the window glass.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an automobile air conditioner will be described below with reference to the drawings.
In FIG. 2 schematically showing the overall configuration, an air conditioner 11
Is a duct 12 for guiding conditioned air into the vehicle compartment, a blower 13 as an air blowing means for introducing air into the duct 12 and blowing the air into the vehicle compartment, a refrigeration cycle 14 as a dehumidifying means, a heater core 15 as a heating means, and a determining means. Further, the air conditioner control device 16 having the function of the control means is provided.

The blower 13 drives a centrifugal fan 13a by a blower motor 13b to blow air, and is housed in a blower case 13c. Blower motor 13b
Is supplied with an applied voltage (blower voltage) according to a control signal supplied from the air conditioner control device 16 via the drive circuit 17, and the rotational speed is determined by the applied voltage, whereby the air flow rate of the fan 13a is set. To be done. The blower case 13c is formed with an inside air inlet 18 for introducing air inside the vehicle (inside air) and an outside air inlet 19 for introducing air outside the vehicle (outside air). These inside air inlet 18 and outside air inlet 19 can be selectively opened / closed by an inside / outside air switching damper 20 as an inside / outside air switching unit according to the setting state of either the inside air circulation mode or the outside air introduction mode.

The downstream end of the duct 12 has a defroster duct 12a, a face duct 12b, and a foot duct 12c.
Is divided into three ducts, and each duct 12a-1
The tip opening of 2c includes a defroster outlet 21, a face outlet 22, and a foot outlet 23 provided in the vehicle compartment.
Are linked to. The defroster outlet 21, the face outlet 22, and the foot outlet 23 can be opened / closed by outlet switching dampers 24a, 24b, 25, respectively.

In the refrigeration cycle 14, the compressor 2 for compressing the refrigerant is sequentially passed through the condenser 27, the receiver 28, the expansion valve 29, and the evaporator 30 as a refrigerant circulation path.
6 is formed by connecting pipes 31 in a ring shape. The compressor 26 is rotationally driven from a traveling engine (not shown) via an electromagnetic clutch 32, and discharges it as a high temperature and high pressure refrigerant. The electromagnetic clutch 32 is driven by a drive circuit 33 according to an on / off control signal from the air conditioner control device 16.

The condenser 27 condenses and liquefies the high-temperature and high-pressure refrigerant by blowing air from the cooling fan 34 and discharges it to the receiver 28. The expansion valve 29 adiabatically expands the liquid refrigerant stored in the receiver 28 and sends it to the evaporator 30. The evaporator 30 is disposed in a downstream portion of the blower 13 in the duct 12, and
The air blown by the air is circulated, and at this time, by exchanging heat with the low-temperature low-pressure refrigerant flowing into the inside, the air is cooled, and at the same time, the air itself evaporates and returns to the compressor 26 again. It is designed to be inhaled.

The heater core 15 is arranged in the duct 12 on the downstream side of the evaporator 30 so that the engine cooling water is circulated therein, and the cooling water is used as a heat source in the duct 12. The circulating air is heated. The heater core 15 is arranged so as to occupy a part of the inside of the duct 12, and a cold air bypass passage 35 is provided so that the air flowing in the duct 12 bypasses the heater core 15.
Then, the amount of air flowing through the duct 12 via the evaporator 30 is adjusted by the air mix damper 36 between the air passing through the cold air bypass passage 35 and the air passing through the heater core 15. There is.

The air conditioner control device 16 is composed of a microcomputer, ROM, RAM (storage means), etc., stores an air conditioning control program, receives an operation signal from the air conditioner operation panel 37, and
Based on detection signals from various sensors described later, each damper (inside / outside air switching damper 20, outlet switching damper 24a,
24b, 25, a drive circuit 17 for supplying a control signal to the corresponding servo motors 38 to 40 to drive the air mix damper 36) and driving the blower motor 13b.
And a control signal is output to the drive circuit 33 of the electromagnetic clutch 32.

The air conditioner operation panel 37 is provided on an instrument panel (not shown) in the vehicle compartment, and includes a temperature setter 41 for setting the room temperature and an automatic air conditioning control. The auto switch 42, the air outlet mode switch 43 for selecting the air outlets 21 to 23, the suction port (the inside air introduction port 18 or the outside air introduction port 1
A suction port mode switch 44 for selecting 9) and an air volume setting switch 45 for setting the air volume of the blower 13 are provided.

As various sensors, an inside air temperature sensor 46 for detecting the temperature inside the vehicle (inside air temperature Tr) and an outside air temperature sensor 4 for detecting the temperature outside the vehicle (outside air temperature Tam).
7, a solar radiation sensor 48 for detecting the solar radiation amount (solar radiation amount Ts),
The temperature of the blown air immediately after passing through the evaporator 30 (the post-evaporation temperature T
The post-evaporation temperature sensor 49 for detecting e), the water temperature sensor 50 for detecting the temperature of the engine cooling water (cooling water temperature Tw), and the humidity sensor 51 for detecting the humidity in the vehicle interior (humidity RH in the vehicle interior) are provided. There is.

Next, regarding the operation of this embodiment, a flow chart of the control program shown in FIGS. 2 to 4 and FIG.
The description will be made with reference to the explanatory views shown in FIGS. In addition,
In the following description, first, (a) an outline of air conditioning control will be described, (b) a failure determination of the humidity sensor 51 will be described, and (c) air conditioning control content corresponding to the operating state of the humidity sensor 51. Will be described.

(A) Outline of Air Conditioning Control First, the outline of the air conditioning control by the air conditioner control device 16 will be described with reference to the flow chart of the control program shown in FIG. That is, the air conditioner control device 1
When the air conditioning control is started according to the control program shown in FIG. 2, 6 first initializes various built-in counters and flags etc. (step S1), and then sets temperature signal Tset set by temperature setter 41. (Step S2), the detection signals T of the various sensors 46 to 51 are read.
r, Tam, Ts, Te, Tw and RH are read (step S3).

Next, in step S4, the air conditioner control device 16 executes the failure determination of the humidity sensor 51 according to the failure determination program shown in FIG. 3, and stores the determination result as described later. In step S5, the target blown air temperature TAO is calculated according to the following equation. TAO = Kset-Tset-Kr-Tr-Kam-Tam-K
sTs + C (1) where Kset is a temperature setting gain, Kr is an inside air temperature gain, Kam is an outside air temperature gain, Ks is a solar radiation gain, and C is a correction constant.

Next, the air conditioner control device 16 causes the blower voltage, the suction port mode, and the blowout port mode to correspond to the set conditions shown in FIGS. 5 to 7, respectively, based on the calculated target blown air temperature TAO. To determine (step S
6-S8). In this case, FIG. 5 to FIG. 7 show the relations between the blower voltage Ve, the suction port mode, and the blowout port mode with respect to the target blown air temperature TAO, and these relations are stored in advance as data inside. .

At step S9, the air conditioner control device 16 calculates and determines the target post-evaporator temperature TEO according to the TEO (target post-evaporator temperature) determination program shown in FIG. 5, as will be described later. In this case, when the humidity sensor 51 is normal, various TEOs are calculated and determined based on the detected humidity RH, and when the humidity sensor 51 is out of order, the target evaporation It is designed to determine the temperature TEO.

After that, the air conditioner control device 16 uses the above-mentioned various data so that the temperature of air blown into the passenger compartment becomes the target air temperature TAO.
The opening degree SW of 6 is calculated according to the following equation (step S
10). SW = [(TAO-Te) / (Tw-Te)] × 100
(%)… (2)

After this, the air conditioner control device 16
Outputs a control signal to each of the servomotors 38 to 40 and the drive circuit 17 so that the above-mentioned various target values can be obtained, and the inside / outside air switching damper 20 and the outlet switching dampers 24a, 24a.
b, 25, the air mix damper 36, and the blower motor 13b are controlled (step S11). Then, when a predetermined control period τ has passed (step S1
2) The air conditioner control device 16 again executes the above step S
The process after 2 is repeated.

(B) Humidity Sensor Failure Judgment Next, the failure judgment operation of the humidity sensor 51 will be described. When the air conditioner control device 16 starts the failure determination program shown in FIG. 3, first in step T1, the humidity RH in the vehicle compartment indicated by the detection signal input from the humidity sensor 51 corresponds to 0% or 100%. If it is operating normally and is "NO", the process proceeds to step T2 to determine whether the compressor 26 is switched from the off state to the on state. here,
When it is determined to be "NO", the failure determination program is terminated (via step T5) and the control program is returned to.

If it is determined to be "YES", that is, immediately after the compressor 26 is turned on, the air conditioner control device 16 proceeds to step T3 and checks flag M.
While setting F to "1", the counting operation of the built-in timer TCon for counting the operating time of the compressor 26 is started, and in the subsequent step T4, the detected humidity RH of the humidity sensor 51 at that time is stored as the off-time data RHH. To do.

Next, the air conditioner control unit 16 judges "YES" because the check flag MF is "1" at step T5 and shifts to step T6 where the count time TCon of the built-in timer is read. Then, it is determined whether or not the count time TCon has passed a predetermined time α (for example, several minutes to several tens of minutes) (step T6). Here, when the count time TCon has not reached the predetermined time α, the air conditioner control device 16 determines “NO”, returns to the control program, and repeats the above steps. When it is determined to be "YES", the process proceeds to step T8, the check flag MF is set to "0", and the count value of the built-in timer TCon is cleared to "0".

Next, the air conditioner control device 16 reads the detection signal Rh from the humidity sensor 51, and the humidity RH at that time is read.
Is the off-time data RHH previously stored in step T4.
It is determined whether or not the values are substantially equal to. That is, at this time, the humidity RH detected by the humidity sensor 51 should correspond to the humidity in the room after a predetermined time has elapsed since the compressor 26 was started, so that the humidity sensor 51 does not normally detect the humidity. If so, the value is lower than the off-time data RHH. Therefore, the air conditioner control device 16 determines “NO” here, confirms the normal state of the humidity sensor 51, and then returns to the control program. Come to do.

However, as described above, the humidity sensor 5
No. 1 has no disconnection or short-circuit failure, but is in a state of characteristic deterioration due to aging or adhesion of chemicals, dust, etc., and characteristic fluctuations have occurred as shown in FIG. 14 shown in the section of the conventional example. In this case, even if a detection error is included, the detected humidity RH may fluctuate slightly, so that the air conditioner control device 16 determines “YES” in step T9 and proceeds to step T10. Then, "1" is set to the failure flag F as a value indicating the failure state, the program is terminated, and thereafter, the control program is returned to.

In step T1 described above, "YE
S ”, that is, the humidity sensor 51 has failed due to a disconnection or a short circuit, and the detection signal R
When the value of the detected humidity RH based on h corresponds to 0% or 100%, the air conditioner control device 16 jumps to step T10 and sets the value of the failure flag F to "1" to set the control program. It is supposed to return to.

(C) Air Conditioning Control Corresponding to Operating State of Humidity Sensor Next, with respect to the value of the target post-evaporation temperature TEO determined in step S9 of the control program, the above-mentioned humidity sensor 51 is used.
The description will be made in correspondence with the failure determination result. In this case, the air conditioner control device 16 first determines in step P1 whether or not the failure flag F is set (F = "1"), and the humidity sensor 51 is operating normally and the failure flag F is determined.
When the value of is "0", the process proceeds to the step for performing normal control of the shift to step P2.

That is, the air conditioner control device 16 determines the absolute humidity RHz in the vehicle compartment from the data of the humidity RH detected by the humidity sensor 51 and the inside air temperature Tr detected by the inside air temperature sensor 46 in step P2. To calculate. Next, in step P3, the target post-evaporation temperature TEO-A required for air conditioning is set according to the conditions of the following equation. When TAO> Tin + α TEO-A = 100 (temporary value) When TAO ≦ Tin + α TEO-A = TAO-β (3)

In this case, the value of Tin indicates the temperature of intake air to the evaporator 30, which is the setting state of the suction port mode switch 44 and the air introduced into the duct 12 in accordance with the setting state. The temperature is obtained based on the detection signal of the inside air temperature sensor 46 or the outside air temperature sensor 47. When the intake air temperature Tin is lower than the target outlet air temperature TAO, that is, when it is not necessary to operate the refrigeration cycle 14, the target post-evaporator temperature TEO-A.
Is set as a very large provisional value "100", and when the intake air temperature Tin is equal to or higher than the target outlet air temperature TAO, as shown in FIG. 8, a value considering the temperature increase β inside the air conditioner 11 is taken into consideration. Set to. However, TE
Regarding the value of OA, the lower limit value is the frost limit temperature T1 of the evaporator 30, and the upper limit value is the set temperature T2 for preventing the odor.

Next, in step P4, the air conditioner control unit 16 determines the target post-evaporator temperature TEO-B required to maintain the humidity comfort in the vehicle compartment. In this case, generally, the comfortable humidity range for human beings is 20 to 60% as the relative humidity when the room temperature is 25 ° C. Therefore, the humidity is controlled to fall within this range in the air conditioning operation state. Therefore, the value of absolute humidity RHz, which is the index, is calculated from the correlation as shown in FIG. 9 based on the absolute humidity RHz1 and RHz2 when the relative humidity RH is 20% and 60% at room temperature of 25 ° C. Find the temperature TEO-B.

Subsequently, proceeding to step P5, the air conditioner control device 16 determines the target post-evaporator temperature TEO-C necessary for preventing the window from fogging. In this case, the fogging generated on the window glass is generally the temperature of the surface of the window glass on the vehicle interior side and the absolute humidity RHz in the vehicle interior.
The air conditioner control device 16
The target post-evaporation temperature TEO-C can be set as follows. The temperature of the window glass inside the passenger compartment is
Although it depends on the outside air temperature Tam, the inside air temperature Tr, the vehicle speed, and the setting conditions of the outlet mode, it is assumed here that the outside air temperature Tam is set for simplicity. Further, since the absolute humidity RHW at which clouding occurs at the temperature inside the vehicle interior of the windshield can be obtained from the moist air diagram,
The absolute humidity RHW and the absolute humidity RH in the passenger compartment at that time
It can be determined from the value of the difference from z (= RHW-RHz) whether or not it is in the state where fogging occurs, and the target post-evaporation temperature TEO-C is set based on the relationship shown in FIG. Become.

Now, when the three target post-evaporation temperatures TEO-A, TEO-B, and TEO-C are obtained in this way, next,
The air conditioner control device 16 sets the one showing the smallest value among these values as the final target post-evaporator temperature TEO (step P6). That is, TEO = MIN (TEO-A, TEO-B, TEO-C) (4). Then, the air conditioner control device 16 controls the operation of the compressor 26 by performing on / off control of the electromagnetic clutch 32 through the drive circuit 33 as shown in FIG. 12 so that the target post-evaporator temperature TEO is reached. (Step P7).

Next, the case where the humidity sensor 51 is out of order, that is, the case where the value of the failure flag F is set to "1" and "YES" is determined in step P1 will be described. That is, in this case, the air conditioner control device 16 determines in step P8 whether or not the inside air circulation mode is currently set, and, for example, when the inside air circulation mode is set, the air conditioner control is performed. Device 16
Judges "YES" and proceeds to step P9 to set the target post-evaporation temperature TEO-D for comfort to the set temperature T2 for preventing the odor, thereby making it correspond to the predetermined humidity value.

When the outside air mode is set, "N
When it is determined to be “O”, the air conditioner control device 16
In step P10, the target post-evaporation temperature TEO-D for comfort is set to "100" to correspond to the predetermined humidity value. Then, the air conditioner control device 16
When the process proceeds to step P11, the target post-evaporator temperature TEO-E for air conditioning is calculated in the same manner as in the case where the above-described step P3 is calculated.

Next, the air conditioner control unit 16 estimates the target post-evaporation temperature TEO-F for anti-fogging (step P1).
2). That is, the value of the target post-evaporator temperature TEO-F is as shown in FIG.
As shown in FIG. 1, for example, the condition is set according to the value of the outside air temperature Tam as a condition that the window glass is not fogged when there are two passengers, the relative humidity of the outside air is 70%, and the vehicle speed is 40 km / h. The value is stored, and the target post-evaporation temperature TEO-F corresponding to the outside air temperature Tam at that time is read and set.

Thereafter, the air conditioner control unit 16 controls the obtained target post-evaporator temperatures TEO-D, TEO-E and TEO-F.
The one showing the smallest value among the above values is set as the final target post-evaporation temperature TEO (step P
13). That is, TEO = MIN (TEO-D, TEO-E, TEO-F) (5). Then, the air conditioner control device 16 controls the operation of the compressor 26 by performing on / off control of the electromagnetic clutch 32 through the drive circuit 33 as shown in FIG. 12 so that the target post-evaporator temperature TEO is reached. (Step P7).

As a result, even if the humidity sensor 51 fails, the necessary conditions are estimated according to the set conditions such as the inside air temperature Tr, the outside air temperature Tam, and the set state of the inside air circulation mode to prevent the window from fogging. As described above, the air conditioning control can be performed, and the safety can be improved during traveling.

According to this embodiment, the following effects can be obtained. That is, first, when the air conditioner control device 16 compares the humidity detected by the humidity sensor 51 when the compressor 26 is turned on with the humidity detected by the humidity sensor 51 at the time when a predetermined time has elapsed, there is no change. Since the failure state of the humidity sensor 51 is determined, in addition to the detection of the disconnection or the short-circuit failure, it is possible to quickly and accurately detect the characteristic deterioration of the humidity sensor 51 due to aging.

Secondly, when the air conditioner control device 16 determines that the humidity sensor 51 has failed, the humidity condition when the internal air circulation mode is set is set corresponding to the condition for operating the compressor 26. When the outside air introduction mode is set, the condition of stopping the compressor 26 is set as the humidity condition to control the operation of the compressor 26, so that the anti-fogging property for preventing the occurrence of fogging in the window of the passenger compartment is maintained. However, it is possible to perform air conditioning control with excellent power saving.

Thirdly, the air conditioner control device 16 determines whether or not the humidity sensor 51 has failed at the time when the compressor 26 is switched from the off state to the on state. By comparing the change in the detection output of the humidity sensor 51 under the environment, it becomes possible to quickly and surely determine the failure state of the humidity sensor 51.

The present invention is not limited to the above embodiment, but can be modified or expanded as follows. A temperature sensor that directly detects the intake air temperature Tin may be provided.
It is possible to provide a notifying means for notifying the failure state of the humidity sensor when it is determined. In this case, a display means such as a lamp or a sounding means such as a buzzer arranged in the vehicle compartment can be used as the notification means. The compressor 26 is stopped when the outside air temperature Tam is 0 ° C. or less, but when dehumidification is required, the defrost mode can be set.

The vehicle air conditioner can be applied to a structure using a reheat type heating means instead of the air mix type air conditioner of this embodiment. In the case of the reheat type air conditioner, the valve opening degree of the flow rate control valve for the cooling water of the engine can be adjusted by, for example, duty ratio control. It can also be applied to a variable capacity refrigeration cycle using a variable capacity compressor. It can also be applied to an EPR type refrigeration cycle using an evaporation pressure control valve between an evaporator and a compressor. It can be applied to all air conditioners that use dehumidifying means. It can be applied to an air conditioner that also has the function of controlling air conditioning for cooling and heating.

[0057]

That is, according to the failure determination device of the humidity sensor of the first aspect, the determination means is based on the change in the detection output of the humidity sensor at that time under the condition that the operation of the dehumidifying means is switched on and off. Since the failure is determined, it is possible to reliably determine the operating state from the change in the detection output of the humidity sensor that should be obtained corresponding to the indoor humidity that changes when the operation of the dehumidifying unit is switched on and off. Therefore, not only the short-circuit failure or disconnection failure of the humidity sensor but also the failure state can be determined in response to the characteristic variation due to deterioration.

According to another aspect of the humidity sensor failure determination apparatus of the present invention, the determination means determines the failure determination operation of the humidity sensor, the detection output of the humidity sensor at the time of switching the operation of the dehumidifying means on and off, and the elapse of a predetermined time. Since the comparison is made with the detection output of the subsequent humidity sensor, the humidity sensor failure judgment operation can be performed reliably under certain conditions in response to changes in the indoor humidity that accompany the on / off switching of the operation of the dehumidifying means. There is an excellent effect that can be performed.

According to the humidity sensor failure determination device of the third aspect, the determination means performs the failure determination operation of the humidity sensor on the basis of the time point when the operation of the dehumidifying means is switched from the off state to the on state. Therefore, it becomes possible to perform the failure determination operation in a state where the humidity sensor is placed in a humidity control environment in which the humidity inside the room is controlled by starting the operation of the dehumidifying means, and the humidity determination can be performed quickly and reliably. This has an excellent effect that the failure determination of the sensor can be performed quickly and reliably.

According to the fourth aspect of the present invention, when the control means determines that the humidity sensor has failed, the control means sets a predetermined humidity condition in accordance with the setting state of the inside / outside air switching means, and Since it is configured to control the dehumidifying means, the humidity condition to be set is based on that it is expected that the window glass will be fogged when the inside / outside air switching means is set to the inside air circulation mode. Set the humidity value so that the dehumidifying means operates, and when the outside air introduction mode is set, set the humidity value so that the dehumidifying means does not operate unnecessarily because there is almost no fogging on the window glass. By doing so, even if the humidity sensor is out of order, the operation of the dehumidifying means can be controlled so as to save power while at the same time preventing fogging of the window glass. Uninaru.

According to the vehicle air conditioner of claim 5,
Even if the characteristics of the humidity sensor have deteriorated, it is possible to detect the failure state from the operating state and control the dehumidifying means in response to this, and even if the humidity sensor has failed. The excellent effect that the operation control of the dehumidifying means can be performed so as to save power while at the same time preventing fogging of the window glass at the minimum.

According to the vehicle air conditioner of claim 6,
Even if the characteristics of the humidity sensor are deteriorated, it becomes possible to detect the failure state reliably and quickly from the operating state and control the dehumidifying means in response to this, and the humidity sensor has failed. Even in such a case, there is an excellent effect that the operation control of the dehumidifying means can be performed so as to save the power while preventing the fogging of the window glass at the minimum.

[Brief description of drawings]

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

[Figure 2] Air conditioning control program (Part 1)

FIG. 3 is a sensor failure determination routine of an air conditioning control program (No. 2)

FIG. 4 is a control routine for a sensor failure of an air conditioning control program (part 3).

FIG. 5 is a diagram showing a relationship between a target blown air temperature TAO and a blower voltage Ve to be set.

FIG. 6 is a diagram showing a relationship between a target outlet air temperature TAO and a set inlet mode.

FIG. 7 is a diagram showing a relationship between a target outlet air temperature TAO and a set outlet mode.

FIG. 8 is a diagram showing a relationship between a target outlet air temperature TAO and a target post-evaporator temperature TEO-A.

FIG. 9: Target post-evaporator temperature TEO set with relative humidity RH
-Figure showing the relationship with B

FIG. 10 is a diagram showing a relationship between a humidity difference and a target post-evaporator temperature TEO-C to be set.

FIG. 11 is a target post-evaporator temperature T set with the outside air temperature Tam.
Diagram showing the relationship with EO-E

FIG. 12 is a diagram showing the relationship between the post-evaporation temperature Te and the operation of the compressor.

FIG. 13 is a block diagram of a conventional humidity sensor.

FIG. 14 is a diagram showing detection characteristics of a humidity sensor and deteriorated detection characteristics.

[Explanation of symbols]

11 is an air conditioner, 12 is a duct, 13 is a blower (blowing means), 14 is a refrigeration cycle, 15 is a heater core, 16 is an air conditioner control device (control means), 20 is an inside / outside air switching damper, 26 is a compressor, and 27 is Condenser, 29 is expansion valve, 30
Is an evaporator, 32 is an electromagnetic clutch, 34 is a cooling fan, 3
5 is a cold air bypass path, 36 is an air mix damper, 37
Is an air conditioner operation panel, 46 is an inside air sensor, 47 is an outside air sensor, 48 is a solar radiation sensor, 49 is an after-evaporation sensor, 50
Is a water temperature sensor and 51 is a humidity sensor.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seifumi Kawashima 1-1-1, Showa-cho, Kariya city, Aichi prefecture Nihon Denso Co., Ltd.

Claims (6)

[Claims] 1. A humidity sensor for detecting the humidity inside a room, the humidity of which is controlled by the operation of the dehumidifying means, based on a change in the detection output of the humidity sensor at that time under the condition that the operation of the dehumidifying means is switched on and off. A failure determination device for a humidity sensor, comprising: a determination unit for determining a failure of the humidity sensor. 2. The determination means determines the failure of the humidity sensor by comparing the detection output of the humidity sensor after the dehumidifying means is switched on and off and after a predetermined time has elapsed from the switching time. The failure determination device for the humidity sensor according to claim 1. 3. The determination means is configured to determine a failure of the humidity sensor based on an on / off switching time point at which the dehumidifying means is switched from an off state to an on state. The failure determination device for the humidity sensor according to 2. 4. An air blowing means for blowing air into the vehicle compartment, an inside air / outside air switching means capable of switching the air blown by the air blowing means to either inside air circulation or outside air introduction, and a humidity sensor for detecting the humidity in the vehicle interior. The dehumidifying means for dehumidifying the interior of the vehicle based on the detection output of the humidity sensor, and the failure determination device for the humidity sensor according to claim 1, wherein the determination means in the failure determination device for the humidity sensor A vehicle air conditioner comprising a control means for controlling the dehumidifying means by setting a predetermined humidity condition in accordance with the set state of the inside / outside air switching means when a failure of the humidity sensor is determined. . 5. An air blowing means for blowing air into the vehicle compartment, an inside air / outside air switching means capable of switching the air blown by the air blowing means to either inside air circulation or outside air introduction, and a humidity sensor for detecting the humidity in the vehicle interior. The dehumidifying means for dehumidifying the vehicle interior based on the detection output of the humidity sensor, and the failure determination device for the humidity sensor according to claim 2, wherein the determination means in the failure determination device for the humidity sensor A vehicle air conditioner comprising a control means for controlling the dehumidifying means by setting a predetermined humidity condition in accordance with the set state of the inside / outside air switching means when a failure of the humidity sensor is determined. . 6. An air blower for blowing air into the vehicle compartment, an inside air / outside air switching means capable of switching the air blown by the air blower to either inside air circulation or outside air introduction, and a humidity sensor for detecting the humidity in the vehicle interior. The dehumidifying means for dehumidifying the vehicle interior based on the detection output of the humidity sensor, and the failure determination device for the humidity sensor according to claim 3, wherein the determination means in the failure determination device for the humidity sensor A vehicle air conditioner comprising a control means for controlling the dehumidifying means by setting a predetermined humidity condition in accordance with the set state of the inside / outside air switching means when a failure of the humidity sensor is determined. .