JP2005262989A - Temperature detector for heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature detector for a heat exchanger capable of detecting the surface temperature of the heat exchanger with high accuracy. <P>SOLUTION: An infrared ray sensor 20 to detect the surface temperature of an evaporator 10 in a non-contact manner is applied as a temperature detector for the evaporator to detect the surface temperature of the evaporator 10. The surface temperature of the evaporator 10 can be detected with higher accuracy than that of a known temperature sensor while the surface temperature of the evaporator 10 is detected in a non-contact manner. A plurality of infrared ray sensors 20 are arranged in a substantially uniform manner on the leeway side of the evaporator 10, and even when a temperature distribution (the high/low distribution) on the surface of the evaporator 10 is changed, the surface temperature (for example, the lowest temperature) of the evaporator 10 can be detected with high accuracy by one of the infrared ray sensors 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat exchanger temperature detection device that detects a surface temperature of a heat exchanger.

  For example, a cooling device in an air conditioner such as an automobile is composed of an evaporator, a compressor, etc., and the evaporator as a heat exchanger exchanges heat between the refrigerant pumped by the compressor and the air in the vehicle interior, etc. It has a function of cooling air. In the evaporator, a temperature sensor is installed as an evaporator temperature detection device that detects the surface temperature of the evaporator. Then, based on the temperature detected by the temperature sensor, the evaporator freezing prevention control (for example, the compressor ON / OFF control is performed and the refrigerant pumping amount is controlled) is performed so that the fin on the evaporator surface is not frozen. .

  Here, since the temperature sensor detects the surface temperature of the evaporator by heat conduction from the evaporator, the surface temperature of the evaporator can be detected with higher accuracy when the temperature sensor is in direct contact with the evaporator. However, the fin provided on the surface of the evaporator is thin and has a wide heat dissipation area (that is, has flexibility) in order to improve heat dissipation. Therefore, it is difficult to fix the temperature sensor in direct contact with the fin.

Therefore, for example, as in the method disclosed in Patent Document 1, a holder is integrally provided on the refrigerant passage plate of the evaporator, and the temperature sensor is fixed by the holder, so that the temperature detection element (thermistor) is leeward of the evaporator. There are some that are firmly fixed to the side to improve the temperature detection accuracy.
JP-A-6-48164

  However, the temperature sensor shown in Patent Document 1 detects the temperature of air that has undergone heat exchange in place of the temperature of the fin (the evaporator surface). Therefore, the temperature sensor is not in direct contact with the fin, and the temperature of the fin (evaporator surface) is transmitted to the temperature sensor via air, so that an error occurs between the detected temperature and the actual temperature of the fin (evaporator surface). . That is, the surface temperature of the evaporator cannot be detected with high accuracy.

  In order to prevent the evaporator from freezing, one temperature sensor measures the temperature distribution of the evaporator at the time of prototyping and the like, and one temperature sensor is installed at the lowest temperature position. However, the minimum temperature position of the evaporator may change due to frost on the fins or clogging of the filter installed before the evaporator. In this case, since the distance between the temperature sensor and the minimum temperature position of the evaporator becomes long, the detection error becomes large. That is, the temperature sensor cannot accurately detect the surface temperature (minimum temperature) of the evaporator.

  An object of this invention is to provide the temperature detection apparatus for heat exchangers which can detect the surface temperature of a heat exchanger accurately in view of the said problem.

  In order to achieve the above object, the invention described in claim 1 is an invention relating to a temperature detector for a heat exchanger that detects the surface temperature of the heat exchanger. A plurality of infrared sensors that detect the surface temperature of the heat exchanger in a non-contact manner are applied.

  As described above, since the infrared sensor is applied as the temperature detection device for the heat exchanger, the surface temperature of the heat exchanger is detected in a non-contact manner, but the heat exchanger has a higher accuracy than the conventional temperature sensor. The surface temperature can be detected. Moreover, since it has a plurality of infrared sensors as a temperature detector for the heat exchanger, even if the temperature distribution (high and low distribution) on the surface of the heat exchanger changes, the surface temperature of the heat exchanger (for example, heat exchange) It is possible to accurately detect the maximum temperature or the minimum temperature on the surface of the vessel.

  In that case, it is preferable that the plurality of infrared sensors are arranged substantially uniformly with respect to the rear surface of the heat exchanger so as to cover the entire rear surface of the heat exchanger.

  Moreover, the heat exchanger should just have at least one of a cooler and a heater. For example, when the heat exchanger has a cooler for cooling the fluid as described in claim 3, the cooler is based on the detection signal of the infrared sensor indicating the lowest temperature among the plurality of infrared sensors. It is preferable that the anti-freezing control is performed. Even if the temperature distribution (high and low distribution) on the cooler surface changes, the minimum temperature on the cooler surface can be detected by any of the plurality of infrared sensors. Therefore, the cooler can be more reliably prevented from freezing based on the detection signal of the infrared sensor indicating the minimum temperature.

  At that time, as described in claim 4, the plurality of infrared sensors are effective for preventing the cooler from freezing if the temperature is adjusted so that a temperature in the vicinity of 0 ° C. can be accurately detected.

  In addition, as a cooler, the evaporator which comprises the air conditioning apparatus for motor vehicles as described in Claim 5, for example can be applied.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
The temperature detector for heat exchanger in the present embodiment is suitable for detecting the surface temperature of the heat exchanger (cooler and / or heater) in a non-contact manner. In the present embodiment, an example in which a temperature detector for a heat exchanger is applied to an evaporator (cooler) that constitutes a cooling device in an automotive air conditioner is shown, and FIGS. 1 (a) and 1 (b) are shown. It explains using. 1A is a perspective view showing a schematic configuration in which a heat exchanger temperature detector is arranged with respect to an evaporator, and FIG. 1B is a perspective view of FIG. 1B from the arrangement side of the heat exchanger temperature detector. FIG.

  As shown in FIGS. 1A and 1B, the evaporator 10 includes a plurality of refrigerant passage plates 11 and, for example, bellows-like fins 12 disposed between the refrigerant passage plates 11. The When the air passes between the fins 12 and the air passage 13 including the refrigerant passage plate 11, the air comes into contact with the fins 12 and the refrigerant passage plate 11 and heat is taken away, so that the air is cooled. The

  In order to detect the surface temperature of the evaporator 10, an evaporator temperature detector as a heat exchanger temperature detector is disposed on the windward surface (rear surface) of the evaporator 10.

  Conventionally, a temperature sensor such as a thermistor has been applied as the evaporator temperature detector. Since this temperature sensor detects the surface temperature of the evaporator 10 by heat conduction from the evaporator 10, the surface temperature of the evaporator 10 can be detected with higher accuracy when it is in direct contact with the evaporator 10. However, since the fins 12 provided on the surface of the evaporator 10 are thin and have a wide heat dissipation area (that is, have flexibility) in order to improve heat dissipation, the temperature sensor is connected to the evaporator 10. It is difficult to directly contact and fix the fins 12.

  On the other hand, for example, there is a configuration in which a holder (not shown) is integrally provided on the refrigerant passage plate 11 of the evaporator 10 and the temperature sensor is firmly fixed to the leeward side of the evaporator 10 with the holder. In this case, the temperature sensor can be prevented from falling off, and the surface temperature of the evaporator 10 can be detected stably.

  However, the temperature sensor is fixed apart from the evaporator 10 and detects the temperature of the heat-exchanged air instead of the temperature of the fin 12 (the surface of the evaporator 10) (that is, the temperature of the fin 12 reduces the air). To the temperature sensor). Therefore, an error occurs between the temperature detected by the temperature sensor and the actual temperature of the fin 12 (the surface of the evaporator 10).

  In order to prevent the normal evaporator 10 from freezing, for example, the temperature distribution of the evaporator 10 is measured under a predetermined condition in a prototype stage. And one above-mentioned temperature sensor is installed in the position with the lowest temperature of the surface of the evaporator 10 based on a measurement result.

  However, the minimum temperature position of the evaporator 10 is changed due to changes in the amount of air passing due to frost on the fins 12 or clogging of a filter (not shown) installed in front of the evaporator 10, changes in atmospheric conditions (temperature, humidity), and the like. May change. In this case, since the distance between the temperature sensor and the lowest temperature position of the evaporator 10 is increased, the above-described detection error is increased. In addition, it takes time until the temperature sensor detects the surface temperature of the evaporator 10 (responsiveness deteriorates).

  Thus, it is difficult to accurately detect the surface temperature of the evaporator 10 in a non-contact manner with a single temperature sensor. Therefore, with such a configuration, there is a possibility that the surface of the evaporator 10 is frozen and cooling is not effective.

  On the other hand, in this embodiment, the infrared sensor 20 is applied as an evaporator temperature detector. The infrared sensor 20 detects the temperature of an object in a non-contact manner from the amount of infrared radiation emitted by the object. The kind is not specifically limited, For example, a thermopile type, a bolometer type, a pyroelectric type, etc. are applicable. In the present embodiment, a thermopile type infrared sensor 20 that can be formed by a normal semiconductor process is applied. In FIG. 1A, reference numeral 21 denotes a support member for supporting and fixing the infrared sensor 20 at a predetermined distance on the wind surface (rear surface) of the evaporator 10. The support member 21 may be any member that can support and fix the infrared sensor 20 at a predetermined distance on the windward surface (rear surface) of the evaporator 10, and is not limited to the configuration shown in FIG. Absent.

  As described above, by applying the infrared sensor 20 as an evaporator temperature detector, it is difficult to fix the evaporator temperature detector in contact with the evaporator 10, and the surface temperature of the evaporator 10 can be detected without contact. Even if it is the structure to perform, the surface temperature of the evaporator 10 can be detected more accurately than before. Note that the sensitivity of the infrared sensor 20 in the present embodiment is adjusted so that a temperature around 0 ° C. can be detected with high accuracy. Therefore, it is more effective for preventing the evaporator 10 from freezing.

  In addition, as shown in FIGS. 1A and 1B, a plurality of infrared sensors 20 are arranged with respect to the evaporator 10. Therefore, even if the temperature distribution (high and low distribution) on the surface of the evaporator 10 changes (that is, the minimum temperature position changes), the minimum temperature on the surface of the evaporator 10 can be accurately detected by any one of the infrared sensors 20. In the present embodiment, as shown in FIG. 1B, a plurality of infrared sensors 20 are arranged substantially uniformly with respect to the lee surface (rear surface) of the evaporator 10 (so that all the lee surfaces of the evaporator 10 are covered). I have to. Therefore, no matter where the minimum temperature position changes, any one of the infrared sensors 20 can quickly detect the minimum temperature on the surface of the evaporator 10 with high accuracy.

  In the present embodiment, the antifreezing control of the evaporator 10 (for example, the pumping amount of the refrigerant pumped to the evaporator 10) based on the detection signal of the infrared sensor 20 indicating the lowest temperature among the plurality of infrared sensors 20. The compressor is turned on / off for control). Therefore, even if the temperature distribution (high and low distribution) on the surface of the evaporator 10 changes, the evaporator 10 can be more reliably prevented from freezing.

  Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be implemented with various modifications.

  In the present embodiment, the example in which the freeze prevention control of the evaporator 10 is performed based on the detection signal of the infrared sensor 20 indicating the lowest temperature among the plurality of infrared sensors 20 has been shown. However, not only the freeze prevention control of the evaporator 10 but also the temperature control of the air cooled by the evaporator 10 may be implemented.

  Moreover, in this embodiment, the example which applies the infrared sensor 20 to the evaporator 10 which is a cooler was shown. However, the infrared sensor 20 may be applied to a heat exchanger other than the evaporator 10. For example, when a heater is used as a heat exchanger, the surface temperature of the heater (for example, the maximum temperature on the heater surface) is changed even when the temperature distribution on the heater surface changes due to clogging in the flow path. The infrared sensor 20 can quickly and accurately detect.

  Moreover, in this embodiment, the evaporator 10 which is a cooler showed the example which heat-exchanges with the air which is a fluid, and cools air. However, the heat exchanger may be configured to exchange heat with the fluid and to heat or cool the fluid.

It is a figure for demonstrating the temperature detector for heat exchangers in 1st Embodiment of this invention, (a) is a perspective view which shows schematic structure which has arrange | positioned the temperature detector for heat exchangers with respect to the evaporator, ( (b) is the top view which looked at (a) from the arrangement | positioning side of the temperature detector for heat exchangers.

Explanation of symbols

10. Evaporator 11 ... Refrigerant passage plate 12 ... Fin 13 ... Air passage 20 ... Infrared sensor (evaporator temperature detector)

Claims (5)

In the temperature detector for the heat exchanger that detects the surface temperature of the heat exchanger,
A temperature detector for a heat exchanger, wherein a plurality of infrared sensors that detect the surface temperature of the heat exchanger in a non-contact manner are applied.   The temperature detection device for a heat exchanger according to claim 1, wherein the plurality of infrared sensors are disposed substantially uniformly with respect to a rear surface of the heat exchanger.   The heat exchanger includes a cooler that cools the fluid, and freeze prevention control of the cooler is performed based on a detection signal of the infrared sensor that indicates a minimum temperature among the plurality of infrared sensors. The temperature detection device for a heat exchanger according to claim 1 or 2, characterized in that   The temperature detection device for a heat exchanger according to claim 3, wherein the plurality of infrared sensors are adjusted so that temperatures near 0 ° C can be detected with high accuracy.   The temperature detection device for a heat exchanger according to claim 3 or 4, wherein the cooler is an evaporator constituting an air conditioner for an automobile.

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