JPH0650446B2 - Abnormality detection device for temperature sensor for air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is used in an air conditioner that controls an indoor temperature according to inputs from a plurality of temperature sensors, and when an abnormality occurs in the plurality of temperature sensors. The present invention relates to an abnormality detecting device for an air conditioner temperature sensor that detects this abnormality and enables the air conditioner to function normally.

[Conventional technology]

Conventionally, a temperature adjusting device as disclosed in JP-A-56-53913 is known.

Such a conventional device includes a plurality of sensors for detecting and inputting the inside air temperature, the outside air temperature, the set temperature, etc., and automatically adjusts the inside air temperature to the set temperature.

[Problems to be solved by the invention]

In the conventional temperature control device as described above, if the sensor is intermittent or short-circuited, the temperature to be detected by the sensor will be input to the control device as an abnormal value, and the inside air temperature will be kept close to the set temperature. However, there is a problem that the temperature control is disturbed.

In view of these problems, the present invention can minimize the deterioration of the temperature control characteristics when the sensor is abnormal, and can reliably and accurately detect the sensor abnormality that affects the temperature controllability. It is an object of the present invention to provide an abnormality detecting device for an air conditioner temperature sensor that can detect the above.

[Means for Solving the Problems]

In order to achieve the above object, the present invention provides a temperature adjusting means for adjusting the temperature of air blown into a room, an inside air sensor for detecting the inside air temperature in the room, and an electric signal corresponding thereto, and an evaporator. A plurality of temperature sensors including an evaporator outlet air temperature sensor that detects the outlet air temperature and generates an electrical signal corresponding to it, and the air conditioner sets the indoor set temperature, and generates an electrical signal corresponding to this. A room temperature setting device, a converting means for converting electric signals from the plurality of temperature sensors and the room temperature setting device into a digital value, the plurality of temperature sensors converted into digital values by the converting means, and the room temperature setting device From the electric signals from the temperature control means for controlling the temperature adjusting means so that the inside air temperature becomes the set temperature based on the electric signals. A digital value indicating a temperature detected by at least one of the plurality of temperature sensors, which is used in an air conditioner including a control unit, has an upper limit value and a lower limit value set in advance corresponding to a practical range of the sensor. A digital value determining means for determining whether or not the value is between, and the digital value determining means determines that the digital value is not between the upper limit value and the lower limit value. Timing means for timing, duration determination means for determining whether or not the duration measured by the timing means exceeds a preset reference time, and the duration determined by the duration determination means is the reference time. When it is determined that the temperature exceeds the predetermined value, the substitute value inputting means for inputting a preset substitute value to the temperature control means instead of the digital value indicating the detected temperature of the at least one sensor. And the digital value determining means, the clocking means, the duration determining means and the substitute value input means are executed by a subroutine program in a microcomputer, and further, before executing the subroutine program, A plurality of setting means for setting the upper limit value, the lower limit value, and the substitute value are provided corresponding to each of the plurality of temperature sensors, and the program of the subroutine is common to each of the plurality of temperature sensors. The gist is an abnormality detection device for an air conditioner temperature sensor, which is characterized by being used.

The plurality of temperature sensors include the inside air sensor, the evaporator outlet air temperature sensor, and a water temperature sensor, and the setting unit corresponds to each of the inside air sensor, the evaporator outlet air temperature sensor, and the water temperature sensor. Is preferably provided.

[Action]

According to the above invention, the air conditioner operates the room temperature setting device to set the set temperature in the room, and an electric signal corresponding to the set temperature is generated from the room temperature setting device. Further, the electric signal from a plurality of sensors including the inside air sensor and the evaporator outlet air temperature sensor, and the electric signal from the room temperature setting device, the conversion means converts the digital value, the temperature control means based on the digital value, The temperature adjusting means is controlled so that the inside air temperature detected by the inside air sensor becomes the set temperature. As a result, the temperature inside the room is controlled to the temperature set by the air conditioning driver.

Here, when there is an abnormality in the plurality of temperature sensors, the digital value input to the temperature control means is input as an abnormal value, and accordingly, normal indoor air conditioning control is performed. Disappear.

Therefore, in the present invention, whether or not the digital value indicating the detected temperature of at least one of the plurality of temperature sensors is a value between the upper limit value and the lower limit value set corresponding to the practical range of this sensor. The digital value determination means determines whether or not. Here, when it is determined that it is not between the upper limit value and the lower limit value, that is, it is outside the practical range, the time measuring means determines the duration of the determination.

Therefore, the digital value determination means determines whether or not the digital value is an abnormal value, and the time counting means measures the time for which the digital value continues to be an abnormal value.

Then, the continuation time determination means determines whether or not the time measured by the time measuring means exceeds the predetermined reference time. If it is determined that the reference time has been exceeded,
The substitute value input means inputs a preset substitute value to the temperature control means instead of the digital value indicating the temperature detected by the at least one sensor.

Therefore, at least one of the plurality of temperature sensors continues to take an abnormal value beyond the reference time, and only when the abnormality of the sensor becomes certain, the abnormal value is detected using the substitute value. Deterioration of temperature controllability due to the value is prevented.

According to such a configuration of the present invention, immediately after the operation of the air conditioner starts, even when the digital value indicating the inside air temperature is outside the range of the practical range and gradually approaches the practical range, for example, Since time is used as a condition for abnormality determination, it is prevented that the abnormality is immediately determined. Therefore, the upper limit value and the lower limit value of the digital value determination means can be set to a practical range where they can be normally used, and erroneous detection can be prevented even if they are set to values that can detect only extremely abnormal values.

The digital value determination means, the time counting means, the duration determination means, and the substitute value input means are executed by a program of a subroutine in the microcomputer, and the upper limit value, lower limit value, and A plurality of setting means for setting the substitute value is provided corresponding to each of the plurality of temperature sensors, and by executing the program of the subroutine after the setting means respectively set the respective values. ,
The abnormality of each temperature sensor is detected.

For example, the setting means provided corresponding to the inside air sensor of the plurality of setting means sets the upper limit value, the lower limit value, and the substitute value of the inside air sensor, and then the subroutine based on the set values. The program is executed, and the abnormality of the inside air sensor is detected based on the program. And the setting means provided corresponding to the evaporator outlet air temperature sensor among the plurality of setting means sets the upper limit value, the lower limit value, and the substitute value of the evaporator outlet air temperature sensor, and then the same as above. An abnormality of the evaporator outlet air temperature sensor is detected by executing the program of the subroutine. Similarly, the setting means provided corresponding to the other temperature sensor sets the upper limit value, the lower limit value, and the substitute value of the other temperature sensor, and then executes the same subroutine program as described above. , The abnormality detection of the other temperature sensor is performed.

〔The invention's effect〕

As described above, according to the present invention, when the abnormality of at least one of the plurality of temperature sensors is detected, the temperature control is performed using the preset substitute value instead of the abnormality value. Therefore, even if an abnormality occurs in the temperature sensor, it is possible to prevent the temperature controllability of the air conditioner from deteriorating.

Further, according to the present invention, the upper limit value and the lower limit value used in the digital value determination means may be set to values set corresponding to the practical range of the temperature sensor to detect the abnormality of the temperature sensor.

That is, when the indoor air conditioning operation is started, for example, the indoor temperature may temporarily take the upper limit value or the lower limit value set corresponding to the practical range, but it may continue to be taken for a long time. Absent. That is, for example, in an environment in which the indoor temperature is a temperature such as the upper limit value or the lower limit value, the air conditioning driver naturally starts the air conditioning operation, and the indoor temperature is accordingly increased by the reference time. It should be a value within the normal range.

Therefore, when the digital value indicating the temperature detected by the temperature sensor exceeds the upper limit or the lower limit over the reference time, it can be easily determined that the temperature sensor is abnormal.

Then, as described above, since the upper limit value and the lower limit value can be set to values corresponding to the practical range, compared with the case where the upper limit value and the lower limit value are set,
The range between the upper limit value and the lower limit value can be reduced, whereby the resolution when converting the digital value by the conversion means can be increased.

Further, the microcomputer has a limited memory capacity and is not suitable for a plurality of programs, but since the present invention uses a subroutine in common, it is possible to perform sophisticated abnormality detection while simplifying the program.

[Embodiment] An embodiment in which the present invention is applied to an automobile air conditioner will be described below.

FIG. 1 shows an embodiment of the present invention, in which sensors 1 to 5 detect various temperatures, each of which is composed of a resistance voltage dividing circuit including a heat sensitive resistance. Reference numeral 1 is an inside air sensor using a negative characteristic thermistor that detects the inside air temperature and generates an inside air temperature signal. Reference numeral 2 is an evaporator outlet air temperature sensor that uses a negative characteristic thermistor that detects the evaporator outlet air temperature and generates an evaporator outlet temperature signal. 3 is a water temperature sensor using a negative characteristic thermistor for detecting the engine cooling water temperature. Reference numeral 4 denotes an outside air sensor using a negative characteristic thermistor for detecting the outside air temperature. Reference numeral 5 represents a sensor such as a solar radiation sensor or a potentiometer used for controlling an automatic air conditioner. Reference numeral 6 is a control panel provided with a switch group for controlling an air conditioner including a room temperature setting device.

Reference numeral 7 denotes an input circuit including an A / D converter that converts and holds the signals of the sensors 1 to 6 so that they can be digitally processed, and functions to send each data to the computer 8. Reference numeral 8 is a single-chip microcomputer that performs arithmetic processing according to a predetermined air-conditioner control program, and is a few megahertz (M
(3 Hz) crystal oscillator 9 is connected, and a power supply is supplied from an on-vehicle battery, and an operating state is achieved by a voltage of a stabilizing power supply (not shown) that generates a constant stabilizing voltage.

The microcomputer 8 is a ROM that stores a control program, and a CP that performs arithmetic processing according to the contents of this ROM.
U, a RAM for temporarily storing various data, an I / O circuit section for adjusting input / output of various signals, and a one-chip LSI having a clock generating section for generating a reference pulse for each process. is there. This microcomputer 8 calculates signals from various sensors, control panel 6, etc.,
The determination process is performed, and a command signal is sent to the control panel 6, the abnormality display 10, and the drive circuit unit 11 of the actuator that drives the temperature control unit and damper of the air conditioner (not shown). The abnormality display unit 10 has a function of displaying a sensor having a failure and a type of failure according to a command signal from the microcomputer 8 and displaying a failure to a driver.
The drive circuit 11 sends a command signal from the microcomputer 8 to
In addition to the damper drive actuator, this is a drive circuit that converts into an electrical signal that actually operates the actuator including the clutch of the compressor, the blower, and the like. Regarding the mounting position of each sensor and the function of the actuator, reference can be made to JP-A-56-53913.

Next, the operation of the above structure will be described with reference to the flowcharts shown in FIGS. FIG. 2 is a diagram showing a part of the arithmetic processing of the microcomputer 8 according to the present invention. When this air conditioner is operated now, the arithmetic processing of the air conditioner control program is executed. That is,
In step 100, which is the initial set routine,
Initialize each flag and timer. In this program, both the flag and the timer are set to 0, and processing is sequentially performed from the signal input step 110 of step 110. In this signal input step 110, the signals of each sensor and the control panel are sequentially input to the RAM.
Memorize inside. The following steps 111 to 113 are steps for determining a failure of the inside air sensor. Since a subroutine for performing a failure type and a processing at the time of failure is used in step 112, preprocessing for using the subroutine in step 111 is performed. To do.

In step 111, the inside air sensor temperature, the inside air sensor reading upper limit temperature 52 ° C., the lower limit temperature −39 ° C., and the inside air sensor short timer of the constants T, T _M , _TL , TIMS, TIMO, and C used in the subroutine are set. The value, the value of the open air sensor open timer, and the substitute room temperature of 25 ° C at the time of failure are substituted.

Here, T is a digital value, and 52 ° C. and −30 ° C. respectively correspond to the upper limit value and the lower limit value of the practical range of the inside air sensor.

In step 112, the processing of the subroutine shown in FIG. 3 is performed. In FIG. 3, processing is performed from step 200. Step 200 is a step of determining whether T _M <T, that is, whether the inside air temperature is at or above the reading limit of 52 ° C., and YES
In the case of, since the negative characteristic thermistor is short-circuited, the process branches to step 201. 1 in step 201
The short flag A, which is set to 1 if it is shorted for 0 minutes or more, is discriminated. When A = 0, short circuit judgment 1
Since it is the first time or less than 10 minutes, when the short timer TIMS is stopped in step 202, it is started, and when it is already operating, no processing is performed.

In the next step 203, TIMS is the reference time 1
If 0 minutes has elapsed, determine if it is less than 10 minutes, then step 2
Go to 07 and proceed to the process of determining whether an open failure has occurred. When 10 minutes have elapsed in step 203, the short flag A is set to 1 in step 204, the timer TIMS is stopped and the timer value is cleared to 0, and it is considered that a true short-circuit failure has occurred, and step 205 Replace the inside temperature with a substitute value of 25 ° C with
Proceed to step 207. In step 201, A =
If the value is 1, go to step 205. Also, step 20
If NO in 0, the short flag A is set to 0 in step 206, the timer TIMS is stopped, the timer value is cleared to 0, and the process proceeds to step 207.

In order to perform the above processing, when the short-circuit failure of the inside air sensor is released midway, the short-circuit flag automatically becomes A = 0, and the inside air temperature used for control also becomes the temperature read by the inside air sensor. However, since it is determined after step 207 whether or not there is an open failure, which will be described later, in the case of an open failure, the inside air temperature used for control is replaced with the substitute value.

In step 207, the inside air sensor temperature is the read limit value, -39.
In the step of determining whether or not the temperature is lower than ° C, when YES, the processing of steps 208, 209, 210, 211 and 212 is performed. Here, B is an open flag (B = 1 at the time of opening, 0 at the time of normal operation), and TIMO is an open timer, and the processing contents are the same as those in steps 201 to 205 described above.

If NO in step 207, the open flag is set to 0 in step 213, the timer TIMO is stopped, the timer value is cleared to 0, this subroutine is exited, and the post-processing of step 113 shown in FIG. 2 is performed. Become.

In step 113, A, B, TIM in the subroutine
The results of S and TIMO are replaced with the data of the inside air short flag, the inside air open flag, the inside air short timer, and the inside air temperature open timer, and the processing of saving is performed, and the air outlet air temperature sensor is opened in the following steps 114 to 116.
Move to short-circuit discrimination processing.

In step 114, the subroutine constants T, T _M , _TL , TI
MS, TIMO, C, after evaporation sensor temperature, upper limit value 52
℃, lower limit value -39 ℃, EVA short timer, EVA open timer, failure temperature 5 ℃ set, Step 1
In step 15, the subroutine processing of FIG. 3 is performed, and in step 116, A, B, TIMS, T in the subroutine are executed.
The processing of putting the result of IMO into the evaluation short flag, the evaluation open flag, the evaluation short timer, and the evaluation open timer is performed. Further, the process proceeds to the next step 117 to 119 to determine whether the water temperature sensor is open or short. In step 117, the upper limit value of the water temperature sensor temperature is 110 ° C., the lower limit value is 20 ° C., the water temperature short timer, the water temperature open timer, and the failure age temperature of 80 ° C. are set in the subroutine constants.
In step 118, the subroutine processing of FIG. 3 is performed, and in step 119, the processing result is put into the water temperature short flag, the water temperature open flag, the water temperature short timer, and the water temperature open timer.
The process shifts to the open air sensor open / short determination process of 123 to 123.

In step 120, the outside air sensor temperature, the upper limit value 52 ° C., the lower limit value −49 ° C., the outside air short timer, the outside air open timer, and the failure age temperature 25 ° C. are set in the subroutine constants.
In step 121, a subroutine process is performed, and in step 122, the process result is put into the outside air short flag, the outside air open flag, the outside air short timer, and the outside air open timer, and the process proceeds to step 123.

In step 123, since the outside air temperature substitute value of 25 ° C. is entered when the outside air sensor fails, processing for returning to the actual sensor reading value is performed. This means that the internal air temperature, the evaporator outlet air temperature, and the water temperature will stabilize at about 25 ° C, 5 ° C, and 80 ° C after about 10 minutes if the components other than the sensor are operating normally, while the outside air temperature will be , Even if the configuration including the sensor is operating normally, the reading range of the outside air sensor is -49 ° C to 52 ° C,
Alternatively, since other values can also be taken during normal operation, there is a possibility that a substitute value will be used even if it is not a failure, and in order to prevent this, even if there is a failure, processing to substitute the substitute temperature is not performed. .

In the next step 124, according to the result of the open / short flag of each sensor, since the one set to 1 is in failure, a process of outputting a failure display command corresponding to each flag to the anomaly indicator is performed. Then, this program is exited to execute another normal air conditioner control program (not shown), for example, the calculation of the required blowout temperature and the control program of the air conditioner actuator, and this is repeated at a predetermined cycle.

The abnormality indicator 10 may have any configuration. It is also possible to record (store) instead of displaying the abnormality.

In the above-mentioned embodiment, the temperature control section and the drive circuit section 11 of the actuator constitute the temperature control means, and the input circuit 7 including the A / D converter constitutes the conversion means. The control program constitutes temperature control means. Further, steps 200 and 207 of FIG. 3 constitute digital value determining means, steps 202 and 209 constitute time measuring means, and steps 203 and 210 constitute duration determining means, and step 205. And in step 212, the substitute value input means is configured. Further, steps 111, 114 and 117 in FIG. 2 respectively constitute setting means.

[Brief description of drawings]

FIG. 1 is a block diagram of a temperature control device showing an embodiment of the present invention, and FIGS. 2 and 3 are flowcharts showing a control program of a microcomputer 8 in FIG. 1 to 5 ... Sensor, 6 ... Control panel, 7 ... AD
Input circuit having conversion function, 8 ... Microcomputer, 10 ... Abnormality indicator.

Front page continuation (72) Inventor Masatoshi Ohira 1-1, Showa-cho, Kariya, Aichi Prefecture, Nihon Denso Co., Ltd. (72) Masanori Nagama 1-1-1-1, Showa-cho, Kariya, Aichi Nihon Denso Co., Ltd. In-house (72) Inventor Yoshimichi Hara, 1-1, Showa-cho, Kariya city, Aichi Nihon Denso Co., Ltd. (56) Reference JP 56-60912 (JP, A) JP 56-53913 (JP) , A)

Claims (2)

[Claims] 1. A temperature adjusting means for adjusting a temperature of air blown into a room, an inside air sensor for detecting an inside air temperature in the room, and an electric signal corresponding thereto, and an evaporator outlet air temperature. , A plurality of temperature sensors including an evaporator outlet air temperature sensor that generates an electric signal corresponding thereto, and a room temperature setting device that sets an indoor temperature set by the air conditioning driver and generates an electric signal corresponding to the set temperature. Converting means for converting electric signals from the plurality of temperature sensors and the room temperature setting device into digital values, and inputting electric signals from the plurality of temperature sensors and the room temperature setting device converted into digital values by the converting means And a temperature control means for controlling the temperature adjusting means so that the inside air temperature becomes the set temperature based on these electric signals. A digital value used in the apparatus, which indicates the temperature detected by at least one of the plurality of temperature sensors, is a value between an upper limit value and a lower limit value preset corresponding to the practical range of this sensor. Digital value determining means for determining whether or not, when the digital value is determined by the digital value determining means is not a value between the upper limit value and the lower limit value,
Timing means for timing the duration of this determination, a duration determination means for determining whether the duration measured by the timing means exceeds a preset reference time, and the duration determined by the duration determination means. A substitute value input means for inputting a preset substitute value to the temperature control means instead of the digital value indicating the temperature detected by the at least one sensor when it is determined that the time exceeds the reference time. The digital value judging means, the time measuring means, the continuation time judging means and the substitute value input means are executed by a program of a subroutine in a microcomputer, and further, the upper limit value is executed before executing the program of the subroutine. , A plurality of setting means for setting the lower limit value and the substitute value are provided corresponding to each of the plurality of temperature sensors, Abnormality detecting device of a temperature sensor for air-conditioning device, characterized by common use subroutines of the program for each of the plurality of temperature sensors. 2. The plurality of temperature sensors include the inside air sensor, the evaporator outlet air temperature sensor, and a water temperature sensor, and the setting unit includes each of the inside air sensor, the evaporator outlet air temperature sensor, and a water temperature sensor. The abnormality detection device for an air conditioner temperature sensor according to claim 1, wherein the abnormality detection device is provided corresponding to the above.