JP3448483B2 - Error detection method of sensor in vehicle air conditioner - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor for an air conditioner for a vehicle , and more particularly to a method for detecting an error of a solar radiation sensor . [0002] In a vehicle air conditioner, usually,
A plurality of temperature sensors such as a vehicle interior temperature sensor (inside air sensor), a vehicle exterior temperature sensor (outside air sensor), and a solar radiation sensor are used, and signals from these temperature sensors are used for air conditioning control. In order to perform the prescribed control,
All of these temperature sensors must be working properly, and if any of the sensors become abnormal, control will be disrupted. Conventionally, as a method of detecting an abnormal state such as disconnection or short circuit of a temperature sensor, a voltage divided by a thermistor used as a temperature sensor and a resistor is represented by A / A.
Generally, D (analog / digital) conversion and determination by a microcomputer are performed. At this time, the A / D conversion value is read several times, and the filter processing is performed by software, so that stable temperature detection is performed. However, since the vehicle air conditioner is mounted on the vehicle, it is greatly affected by the surrounding environment when the driver is not in the vehicle. For example, if the vehicle is left in the sunshine for a long time, the temperature inside the vehicle in a sealed state becomes high, and the temperature sensor section also becomes high at the same time. If the engine is started in such a state, the microcomputer may read the temperature in the high temperature state as an abnormal state and detect an error even though the temperature sensor itself has no abnormality. That is,
It may not be accurately determined whether the condition is a true error of the sensor. Therefore, an object of the present invention is to pay attention to the above-mentioned problems, and to make it possible to accurately judge whether or not a detected value of a solar radiation sensor is within a range of an error, whether or not it is a true error. And to achieve this inexpensively with virtually no additional components. In order to solve the above-mentioned problems, a method for detecting a sensor error in a vehicle air conditioner according to the present invention is directed to a vehicle using a temperature sensor comprising a solar radiation sensor using a thermistor. In the air conditioner for use, when a state in which the value detected by the temperature sensor is within the error determination range is continued for a certain period of time, the value detected by the sensor is determined to be a true error, and in the error determination, a short circuit is detected. to maximize the solar radiation correction amount when it is determined that the error due to, when it is determined that the error due to disconnection consists wherein the to Turkey minimize solar radiation correction amount. [0008] In the method according to the present invention,
The determination of the error is performed, for example, as follows. An error is not detected for a single error of an A / D (analog / digital) conversion value, which is a detection signal from the target sensor, and an error is detected only when the error is within an error range for a predetermined time. If the A / D value returns to the normal range within a certain time, it is not determined that an error has occurred. In other words, the error detection condition
Add that it is within a certain time error range. Note that the certain time is a sufficient time until the abnormal temperature can be detected as a temperature in a normal range. By such control, it is determined whether or not the sensor is in a true error state.For example, when it is determined that the sensor itself has no abnormality and is a detection value under a bad surrounding environment,
A signal within the above error range is prevented from being erroneously recognized as a true error signal. Then, the error judgment of the solar radiation sensor, solar radiation correction amount when it is determined that the error due to a short circuit is maximized, if it is determined that the error due to disconnection Ru is solar radiation correction amount is minimized. Preferred embodiments of the present invention will be described below with reference to the drawings. Figure 1 shows a flow chart of a basic form of the engagement <br/> Ru method according to the present invention. When this routine is started, first, A / D (analog / digital) conversion of a signal from an error determination target sensor is performed (step S1), and it is determined whether or not the signal is within an error range (step S2). If not in the error range, the error counter is set to 0, the process returns to step S1, and the process is repeated (step S3). If it is within the error range, 1 is added to the error counter (step S4), and it is determined whether or not the state within the error range has continued for a predetermined time, for example, 30 minutes (step S5). When the error is out of the error range and returns to the normal state within a predetermined time, it is determined that the error is not a true error, and the process returns to step S1 to repeat the process. If the state within the error range continues for a certain period of time, it is determined that the sensor is in a true abnormal state. For example, it is determined by a true error due to a failure of the sensor itself (a disconnection or a short circuit). It is determined that there is, and in step S6, error processing of the sensor, for example, failure or abnormal display is performed. FIG. 2 shows a more specific embodiment.
The case where the sensor is a solar radiation sensor using a thermistor is shown. In the flow shown in FIG. 2, when this routine is started, first, the A of the solar radiation sensor using the thermistor is used.
/ D conversion is performed (step S11). Next, the solar radiation error flag is determined. If the solar radiation error flag is 1 (error processing has been completed), the routine ends without updating the solar radiation correction amount (step S12). Next, when the solar radiation error flag = 0, an error determination is performed using the A / D converted value obtained by the above-mentioned A / D conversion (step S13). If it is not within the error range, the solar radiation error counter, which is a dedicated counter for the solar radiation sensor, is cleared (solar radiation error counter = 0) (step S14), and the solar radiation correction amount is calculated and updated using the A / D value (step S14). Step S15). On the other hand, if the error is within the error range in step S13, the solar radiation error counter is counted up (step S16). Then, the value of the solar radiation error counter is
A predetermined time (30 minutes in the example shown in FIG. 2) is compared (step S17). Here, the predetermined time is a time sufficient to return to the normal range by operating the air conditioner immediately after the engine is started, even if the solar radiation sensor is in a normal range even though the solar radiation sensor is normal. is there. If the result of the comparison in step S17 is less than the predetermined time, the error processing is not performed, and the normal calculation of the amount of solar radiation is performed. On the other hand, as a result of the determination in step S17, if the error range is continued for the predetermined time and the value of the solar error counter reaches the predetermined time, the solar error flag is set here (solar error flag = 1). (Step S18), and error processing is performed. In the error processing shown in FIG. 2, the amount of solar radiation correction is maximized when the error is caused by a short circuit, and the amount of solar radiation correction is minimized when the error is caused by a disconnection (depending on the content of the error) ( Steps S19, 20, 2
1). Then, this routine ends. In this case, the solar radiation error flag is set, so that the next time this routine is executed, the solar radiation correction amount is not calculated and updated, so that the solar radiation correction amount is fixed to the above-mentioned maximum value or minimum value. Although not shown in the drawing, the function of correcting the solar radiation can be utilized as much as possible by clearing the solar radiation error flag by restarting the engine. In this way, it is accurately determined whether the detected value of the solar radiation sensor is a true error signal due to a failure of the sensor itself, or whether it has accidentally entered the error range due to bad environmental conditions or the like. In each case, appropriate processing is executed. As described above, according to the method for detecting an error of a sensor in a vehicle air conditioner of the present invention, it is determined whether or not a sensor to be determined is within a true error range. Accurate judgment can be made by judging the time within the range, and erroneous recognition of an error can be avoided at low cost without adding components. Further, since the error range of the sensor itself is used as it is, the error erroneous recognition can be accurately avoided as described above without deleting the same error determination function as the conventional one .

It is a flow chart flow chart of the basic embodiment of the method according to the BRIEF DESCRIPTION OF THE DRAWINGS [Figure 1] present invention. FIG. 2 is a flowchart for implementing a method according to a more specific embodiment of the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60H 1/00 F24F 11/02 G01K 7/24

Claims (1)

(57) [Claim 1] In a vehicle air conditioner using a temperature sensor comprising a solar radiation sensor using a thermistor,
When the state in which the value detected by the temperature sensor is within the error determination range is continued for a certain period of time, the value detected by the sensor is determined to be a true error, and in the error determination, an error due to a short circuit is determined. to maximize the solar radiation correction amount is characterized and to Turkey minimize the solar radiation correction amount when it is determined that the error due to disconnection, the sensor error detecting method in a vehicle air conditioner.