JPH07180882A - Air conditioner - Google Patents

Abstract

PURPOSE:To detect a wire disconnection of a heater and to diagnose the malfunction of the heater by a comparison decision of a heater temperature measured after a predetermined time set after a heater is turned ON. CONSTITUTION:The air conditioner comprises a temperature setting function 1 for setting a heater ON/OFF sensing boundary temperature for recognizing ON/OFF of the heater by a microcomputer, a heater temperature detecting function 2 for detecting a heater temperature, a diagnosing function 4 for comparing the detected heater temperature with a heater ON/OFF sensing boundary temperature to decide it, and a learning function 3 for storing and learning a time at the time of detecting the heater temperature. Thus, a wire disconnection of the heater is sensed for the heater temperature measured after a certain set time is elapsed after the heater is turned ON, thereby diagnosing a heater malfunction time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner having a heater abnormality detecting function.

[0002]

2. Description of the Related Art In a conventional air conditioner equipped with a heater, a protector for detecting a heater temperature against abnormal heating of the heater is installed as disclosed in Japanese Patent Laid-Open No. 3-152331. It was designed to control the current on and off.

[0003]

However, in the above conventional air conditioner equipped with a heater, a protection device for detecting the heater temperature against abnormal heating of the heater is installed, and the protection device turns on / off the current to the heater. Only by controlling, heater abnormality detection such as heater disconnection was not taken into consideration, and serviceability was impaired in terms of heater abnormality diagnosis.

The present invention solves the above-mentioned conventional problems, and an object thereof is to detect heater breakage and enable heater abnormality diagnosis.

Further, the present invention makes it possible to detect not only the breakage of the heater but also the failure of the heater control circuit for turning the heater on and off.

Further, according to the present invention, by learning the set time, the heater temperature after the latest or optimum set time has elapsed is judged, thereby detecting the heater burnout and the heater control circuit. The above failure detection is made more accurate.

[0007]

In order to achieve the above object, the present invention provides a temperature setting function for setting a heater ON / OFF detection boundary temperature for a microcomputer (hereinafter referred to as a microcomputer) to recognize ON / OFF of a heater. It has a heater temperature detection function that detects the heater temperature, a diagnostic function that compares the detected heater temperature with the heater on / off detection boundary temperature and makes a judgment, and a learning function that accumulates the time when the heater temperature is detected. The heater breakage is detected with respect to the heater temperature measured after a lapse of a set time after the heater is turned on, and the diagnosis when the heater is abnormal is made possible.

Furthermore, even after the heater is turned off, it is possible to detect a failure in the heater control circuit for turning the heater on and off by the same measurement and determination with respect to the heater temperature measured after a certain set time has elapsed. It is a thing.

Furthermore, by learning the set time and resetting the time each time, even if there is a change in the heater temperature characteristic that may occur due to the aging of the heater or the like, the latest or optimum set time elapses. By making a determination with respect to the heater temperature after the heating, it is possible to perform more accurate diagnosis of the heater disconnection detection and the heater control circuit failure detection.

[0010]

According to the present invention, in the above structure, the heater ON / OFF detection boundary temperature for recognizing ON / OFF of the heater set in advance in the microcomputer is utilized, and the time when the heater temperature and the detection boundary temperature match after the heater is turned on. It is possible to diagnose the heater burnout by presetting, and by comparing and deciding whether the heater temperature after the set constant time is higher or lower than the detection boundary temperature.

Further, by using the heater on / off detection boundary temperature for recognizing the heater on / off set in advance in the microcomputer, the time when the heater temperature and the detection boundary temperature match after the heater is turned off is set in advance, and By comparing and diagnosing whether the heater temperature after a set fixed time is higher or lower than the detection boundary temperature, it is diagnosed that there is an abnormality in the heater control circuit such as welding of relay contacts on the heater control circuit. It is also possible.

Further, by utilizing the heater ON / OFF detection boundary temperature for recognizing ON / OFF of the heater set in advance in the microcomputer, the time when the heater temperature and the detection boundary temperature match after the heater is turned off is learned, and each time,
Even if there is a change in the heater temperature characteristics that may occur due to aging of the heater, etc. by re-setting the time, the heater temperature after the latest or optimum set time has passed is higher or lower than the detection boundary temperature. Whether or not,
By making a diagnosis, it is possible to make a more accurate diagnosis.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a block diagram that enables diagnosis when the heater of the air conditioner in the embodiment of the present invention is abnormal. 1 is a temperature setting function for setting the heater on / off detection boundary temperature, 2 is a heater temperature detecting function for detecting the heater temperature, 3 is a learning function for accumulating and learning time when the heater temperature is detected, 4 is the detected heater temperature and the above This is a diagnostic function that compares the temperature with the heater on / off detection boundary temperature to make a determination. This block diagram is common to the following first embodiment, second embodiment and third embodiment.

(Embodiment 1) First, a first embodiment of the present invention will be described with reference to FIG. FIG. 2 shows the first of the present invention.
FIG. 9 is a diagram showing a change in the heater temperature, which is a graph showing how the heater temperature of a normal heater changes with time after the heater is turned on in the example of FIG. In FIG. 2, a heater ON / OFF detection boundary temperature (hereinafter referred to as a boundary temperature) for recognizing ON / OFF of the heater is set in advance in the microcomputer, and the heater temperature H and the boundary temperature are set after the heater is turned on. Matching time Td
1 is set in advance. The heater temperature H is measured after the elapse of the set time Td1, and when the measurement result A is higher than the boundary temperature, it can be determined that the heater is normally energized. However, when the measurement result A is lower than the boundary temperature, it is possible to detect that the heater has a break in the heater because the heater temperature H is insufficiently increased even though the heater is turned on. .

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 shows the second aspect of the present invention.
In addition to the state that the heater temperature of the normal heater after the heater is turned on in the example of Example 1 changes with time, the change in the heater temperature that shows the state that the normal heater temperature after the heater is turned off changes with time is shown. FIG. The description of the same contents as in the first embodiment will be omitted. In FIG. 3, a boundary temperature is set in advance in the microcomputer, and a time Td2 when the heater temperature H and the boundary temperature match after the heater is turned off.
Is set in advance. The heater temperature H is measured after the elapse of the set time Td2, and when the measurement result B is lower than the boundary temperature, it can be determined that the heater is normally de-energized. However, when the measurement result B is higher than the boundary temperature, it is determined that the heater temperature H is not sufficiently lowered even though the heater is turned off, and the heater control circuit does not have relay contact welding or the like on the heater control circuit. It is also possible to detect it as an abnormality.

(Embodiment 3) Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a graph showing a temperature change when the heater is turned on, which is a graph showing a state in which the heater temperature of a normal heater after the heater is turned on according to the third embodiment of the present invention changes with time. FIG. 5 is a graph showing a temperature change when the heater is turned off, which is a graph showing how the heater temperature of a normal heater changes with time after the heater is turned off in the third embodiment of the present invention. The description of the same contents as those of the first and second embodiments will be omitted.

In FIG. 4, when the heater is turned on, the characteristic of the heater temperature H changes with the boundary temperature due to the change of the heater temperature characteristic which may occur due to aging of the heater or the like. If the time set in advance is constantly fixed at the same time, accurate determination for the heater temperature measurement immediately after the lapse of time, that is, comparison determination with the boundary temperature becomes unclear. Therefore,
By accumulating and learning the time Tda, Tdb, etc. until reaching the points a and b as data,
The latest or optimum set time Td1 is determined, and the heater temperature H is measured after the set time Td1 has elapsed. When the measurement result C is higher than the boundary temperature, it can be determined that the heater is normally energized. However, when the measurement result C is lower than the boundary temperature, it is possible to more accurately detect the heater disconnection because the heater temperature H is insufficiently increased even though the heater is turned on. It is a thing.

Even when the heater is turned off in FIG. 5, the time Tdc, Tdd, etc. until reaching the points c and d are accumulated as data and learned in the same manner as when the heater is turned on. The optimum set time Td2 is determined, and the heater temperature H is measured after the set time Td2 has elapsed. If the measurement result D is lower than the boundary temperature, it can be determined that the heater is normally de-energized. However, when the measurement result D is higher than the boundary temperature, it is determined that the heater temperature H is not sufficiently decreased even though the heater is turned off, and the relay contact welding or the like on the heater control circuit is performed on the heater control circuit. It is also possible to detect it as an abnormality. In other words, by effectively utilizing the learning function for the set time, even if the heater temperature characteristic changes that the heater temperature H characteristic may occur due to aging of the heater, etc., more accurate heater temperature measurement can be performed. By determining the set time and determining the heater temperature after the set time has elapsed, it becomes possible to detect an abnormality in the heater disconnection and the failure in the heater control circuit with higher accuracy.

[0020]

As is apparent from the above description, the present invention detects the heater disconnection by making a comparative judgment with respect to the heater temperature measured after a set fixed time after the heater is turned on. This makes it possible to diagnose when the heater is abnormal.

Further, even after the heater is turned off, the heater temperature measured after a certain period of time set in the same manner is compared and judged, so that the failure of the heater control circuit for turning the heater on and off can be detected. It is a thing.

Further, by learning the set time and resetting the time each time, even if there is a change in the heater temperature characteristic that may occur due to a change with time of the heater, the latest or optimum set time elapses. By making a determination with respect to the heater temperature after the heating, it is possible to perform more accurate diagnosis of the heater disconnection detection and the heater control circuit failure detection.

[Brief description of drawings]

FIG. 1 is a block diagram that enables diagnosis when a heater abnormality occurs in an air conditioner according to an embodiment of the present invention.

FIG. 2 is a diagram showing a normal change in heater temperature after the heater is turned on in the first embodiment of the present invention.

FIG. 3 is a diagram showing a normal change in heater temperature after a heater-off operation according to the second embodiment of the present invention.

FIG. 4 is a diagram showing a change in heater temperature after the heater is turned on in the third embodiment of the present invention.

FIG. 5 is a diagram showing a change in heater temperature after the heater is turned off.

[Explanation of symbols]

 1 Temperature setting function 2 Heater temperature detection function 3 Learning function 4 Diagnostic function

Claims (3)

[Claims] 1. A temperature setting function for setting a heater on / off detection boundary temperature for the microcomputer to recognize the heater on / off, a heater temperature detection function for detecting the heater temperature, a detected heater temperature and the heater on / off detection boundary. It has a diagnostic function that compares the temperature with the temperature and makes a judgment, and a learning function that accumulates and learns the time when the heater temperature is detected, with respect to the heater temperature measured after a certain set time after the heater is turned on. An air conditioner that detects heater breakage and enables diagnosis when the heater is abnormal. 2. The heater control circuit for turning the heater on and off according to the same measurement and determination as to the heater temperature measured after a set time even after the heater is turned off, in addition to claim 1. An air conditioner that can be detected. 3. In addition to claims 1 and 2, even if there is a change in the heater temperature characteristic that may occur due to secular change of the heater, etc. by learning the set time and resetting the time each time, An air conditioner that enables more accurate diagnosis of heater burnout detection and heater control circuit failure detection by making a determination on the heater temperature after the latest or optimum set time has elapsed.