Refrigerant cycle device and heat-exchanger integrated unit with temperature sensor for the same

Abstract

A refrigerant cycle device includes an ejector having a nozzle portion for decompressing refrigerant and a refrigerant suction port from which refrigerant is drawn by a high-speed refrigerant stream jetted from the nozzle portion, and a refrigerant branch passage branched from an upstream side of the nozzle portion in a refrigerant flow such that refrigerant flows into the refrigerant suction port through the refrigerant branch passage. Furthermore, a first heat exchanger is disposed to evaporate refrigerant flowing out of the ejector, a second heat exchanger is disposed in the refrigerant branch passage to evaporate refrigerant, and a temperature sensor is located to detect a temperature so as to detect a frost in the second heat exchanger. In addition, a controller performs a frost prevention control for reducing the frost in the second heat exchanger, in accordance with the temperature detected by the temperature sensor.

Description

CROSS REFERENCE TO RELATED APPLICATION[0001]This application is based on Japanese Patent Application No. 2006-165106 filed on Jun. 14, 2006, the contents of which are incorporated herein by reference in its entirety.FIELD OF THE INVENTION[0002]The present invention relates to a refrigerant cycle device that includes an ejector serving as refrigerant decompression means and refrigerant circulation means, and a plurality of evaporators. For example, the evaporator is suitable to an air conditioner for a vehicle, or a refrigeration unit for a vehicle for freezing and refrigerating goods mounted on the vehicle. More particularly, the present invention relates to a heat-exchanger integrated unit with a temperature sensor for a refrigerant cycle device having an ejector.BACKGROUND OF THE INVENTION[0003]JP-A-2001-74388 (corresponding to U.S. Pat. No. 6,449,979) discloses a refrigerant cycle device that includes a first evaporator connected to a downstream side of an ejector, and a second e...

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Benefits of technology

[0013]The controller can reduces a discharge capacity of refrigerant discharged from the compressor during the frost prevention control, or can stop operation of the compressor during the frost prevention control. Furthermore, the temperature sensor can be located to detect a temperature of air immediately after passing through the second heat exchanger, or can be located to detect a temperature of one of fins and tubes of the second heat exchanger. Furthermore, the predetermined position may be set close to the lower tank.

[0014]According to another example of the present invention, a heat-exchanger integrated unit for a refrigerant cycle device includes a heat exchanger for evaporating refrigerant, an ejector that includes a nozzle portion for decompressing refrigerant and a refrigerant suction port from which refrigerant from the heat exchanger is drawn by a high-speed refrigerant flow jetted from the nozzle portion, and a temperature sensor for detecting a temperature so as to detect a frost in the heat exchanger. Furthermore, the temperature sensor is located in the heat exchanger at a predetermined position at which refrigerant flows upwardly from below. Therefore, when the heat exchanger is used as an evaporator, frost generated on the heat exchanger can be suitably reduced by using the temperature detected by the temperature sensor.

[0015]

Problems solved by technology

Furthermore, in a conventional vapor-compression refrigerant cycle device, when a load to be cooled is small and the temperature of an evaporator is decreased, frost (frosting) occurs on the evaporator.

As a result, a cooling function is not performed effectively.

However, the distribution of refrigerant and air velocity always becomes nonuniform in the evaporator.

At this time, the higher the temperature of a detection point of the temperature sensor, the more the timing of stopping the compressor is delayed, resulting in an excess amount of supply of the refr

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