Air-conditioning apparatus for vehicle

Abstract

An air-conditioning apparatus for a vehicle includes an evaporator and a temperature sensor for detecting the temperature of the evaporator. The evaporator includes three tube groups provided in a leeward tube row, and two tube groups provided in a windward tube row. The flow direction of refrigerant within heat exchange tubes of a farthest tube group of the leeward tube row farthest from a refrigerant inlet is the same as that within heat exchange tubes of a farthest tube group of the windward tube row farthest from a refrigerant outlet. A single path is formed by the two farthest tube groups. The temperature sensor is disposed to detect the temperature of a portion of the evaporator where the farthest tube group of the leeward tube row is provided. The air-conditioning apparatus prevents the temperature of air from greatly changing due to turning on and off of a compressor.

What is claimed is: 
     
         1 . An air-conditioning apparatus for a vehicle comprising a compressor which uses an engine as a drive source and is connected to the engine through clutch means; a condenser for cooling refrigerant compressed by the compressor; a pressure reducer for reducing the pressure of the refrigerant cooled by the condenser; an evaporator for evaporating the refrigerant whose pressure has been reduced by the pressure reducer; and a temperature sensor for detecting the temperature of the evaporator, the air-conditioning apparatus controlling the temperature of the evaporator by turning the compressor on and off on the basis of the temperature detected by the temperature sensor, wherein
 the evaporator includes leeward and windward tube rows which are juxtaposed in an air-passing direction and each of which is composed of a plurality of heat exchange tubes disposed at predetermined intervals in a direction orthogonal to the air-passing direction such that their longitudinal directions coincide with a vertical direction;   the leeward tube row includes three or more tube groups each composed of a plurality of heat exchange tubes, and the windward tube row includes tube groups the number of which is one less than the number of the tube groups of the leeward tube row and each of which is composed of a plurality of heat exchange tubes;   upper and lower ends of the heat exchange tubes of the leeward tube row communicate with leeward upper and lower header sections, respectively, and upper and lower ends of the heat exchange tubes of the windward tube row communicate with windward upper and lower header sections, respectively;   a refrigerant inlet is provided at one end of one leeward header section selected from the leeward upper and lower header sections, and a refrigerant outlet is provided at one end of one windward header section selected from the windward upper and lower header sections in such a manner that the refrigerant outlet and inlet are located side by side in the air-passing direction.   a flow direction of refrigerant within the heat exchange tubes of a farthest tube group of the leeward tube row located at a position farthest from the refrigerant inlet is the same as a flow direction of refrigerant within the heat exchange tubes of a farthest tube group of the windward tube row located at a position farthest from the refrigerant outlet;   a single path is formed by the two farthest tube groups which are juxtaposed in the air-passing direction and which are the same in the flow direction of refrigerant within the heat exchange tubes; and   a single temperature sensor is disposed on the evaporator so as to detect the temperature of a portion of the evaporator where the farthest tube group of the leeward tube row is provided.   
     
     
         2 . An air-conditioning apparatus for a vehicle according to  claim 1 , wherein the temperature sensor is composed of a thermistor, and is attached to a fin disposed between adjacent heat exchange tubes of the farthest tube group of the leeward tube row. 
     
     
         3 . An air-conditioning apparatus for a vehicle according to  claim 1 , wherein
 first through third tube groups each composed of a plurality of heat exchange tubes are provided in the leeward tube row of the evaporator in such a manner that the first through third tube groups are arranged in this order from one end of the leeward tube row on the refrigerant inlet side toward the other end of the leeward tube row;   fourth and fifth tube groups each composed of a plurality of heat exchange tubes are provided in the windward tube row of the evaporator in such a manner that the fourth and fifth tube groups are arranged in this order from one end of the windward tube row opposite the refrigerant outlet toward the other end of the windward tube row located on the refrigerant outlet side;   a predetermined number of sections are provided in each of the leeward upper and lower header sections and the windward upper and lower header sections, whereby the first tube group serves as a first path where the refrigerant flows within the heat exchange tubes from one of upper and lower sides where the refrigerant inlet is located to the opposite side, the second tube group serves as a second path where the refrigerant flows within the heat exchange tubes in a direction opposite the flow direction in the first path, the third and fourth tube groups serve as a third path where the refrigerant flows within the heat exchange tubes in the same direction as the flow direction in the first path, and the fifth tube group serves as a fourth path where the refrigerant flows within the heat exchange tubes in the direction opposite the flow direction in the first path; and   the third and fourth tube groups which are the same in the flow direction of the refrigerant within the heat exchange tubes are juxtaposed in the air-passing direction.