Vehicular air conditioner

Abstract

A first external refrigerant circuit includes a condenser, a pressure reducing device, and an evaporator. A compressor is directly connected to a drive source of the vehicle to permit power transmission and compresses a refrigerant by being driven by the drive source at all times. The compressor and the first external refrigerant circuit form a refrigerant circulation circuit. A second external refrigerant circuit connects a discharge chamber and a suction chamber of the compressor at the outside of the compressor and permits the circulation of a refrigerant that is not involved in air conditioning. Control devices selectively open or close the first external refrigerant circuit and the second external refrigerant circuit, respectively.

1 . A vehicular air conditioner comprising: 
 a first external refrigerant circuit including a condenser, a pressure reducing device, and an evaporator;    a compressor directly connected to a drive source of the vehicle to permit power transmission, wherein the compressor compresses refrigerant by being at all times driven by the drive source, the compressor and the first external refrigerant circuit forming a refrigerant circulation circuit;    a second external refrigerant circuit, which connects a discharge chamber to a suction chamber of said compressor at the outside of said compressor and permits the circulation of the refrigerant that is not involved in air conditioning; and    control means, which selectively open or close said first external refrigerant circuit and said second external refrigerant circuit, respectively.    
     
     
         2 . The vehicular air conditioner according to  claim 1 , wherein said second external refrigerant circuit partially shares its circuit with said first external refrigerant circuit, and said second external refrigerant circuit includes a bypass passage, which connects the discharge chamber to the suction chamber of said compressor in a state where the condenser or the evaporator in said first external refrigerant circuit is bypassed.  
     
     
         3 . The vehicular air conditioner according to  claim 2 , wherein said first external refrigerant circuit includes an accumulator between the evaporator and the suction chamber of said compressor and a low-pressure side of said bypass passage is connected to said first external refrigerant circuit between the evaporator and the accumulator.  
     
     
         4 . The vehicular air conditioner according to  claim 2 , wherein said first external refrigerant circuit includes an internal heat exchanging device, said internal heat exchanging device having a high-pressure side heat exchanger through which the refrigerant flows from the discharge chamber of the compressor to the pressure reducing device, and a low-pressure side heat exchanger through which the refrigerant flows from the evaporator to the suction chamber of the compressor, heat exchange being executed between the high-pressure side and low-pressure side heat exchangers, and that the low-pressure side of said bypass passage is connected between the evaporator and the low-pressure side heat exchanger of the internal heat exchanging device in said first external refrigerant circuit.  
     
     
         5 . The vehicular air conditioner according to  claim 2 , wherein the high-pressure side of said bypass passage is connected between the condenser and the pressure reducing device, in said first external refrigerant circuit.  
     
     
         6 . The vehicular air conditioner according to  claim 2 , wherein said first external refrigerant circuit includes an oil separator for separating oil from the refrigerant between the discharge chamber of the compressor and the condenser, and said oil separator is connected to the suction chamber of the compressor through an oil return passage for returning a separated oil into the compressor, said oil return passage also serving as the bypass passage.  
     
     
         7 . The vehicular air conditioner according to  claim 1 , wherein said first external refrigerant circuit includes an external heat exchanger, which functions as said condenser during the cooling and functions as said evaporator during the heating, and an internal heat exchanger, which functions as said evaporator during the cooling and functions as said condenser during the heating, and 
 said first external refrigerant circuit further includes a switching valve switchable to two positions for switching said first external refrigerant circuit to the cooling mode and the heating mode, and when the first external refrigerant circuit is switched to the cooling mode by the switching valve, a passage from the discharge chamber of the compressor to the suction chamber of the compressor through the external heat exchanger that functions as the condenser and the internal heat exchanger that functions as the evaporator is formed in the first external refrigerant circuit, and that    when the first external refrigerant circuit is switched to the heating mode by said switching valve, a passage from the discharge chamber of the compressor to the suction chamber of the compressor through the internal heat exchanger that functions as the condenser and the external heat exchanger that functions as the evaporator is formed in the first external refrigerant circuit.    
     
     
         8 . The vehicular air conditioner according to  claim 7 , wherein said switching valve can be disposed at a position where said first external refrigerant circuit is shut off and said second external refrigerant circuit is opened, and also serves as said control means.  
     
     
         9 . The vehicular air conditioner according to  claim 1 , wherein the discharge displacement of said compressor can be changed.  
     
     
         10 . The vehicular air conditioner according to  claim 9 , wherein said compressor includes a cam plate and a crank chamber that accommodates the cam plate, a discharge displacement is adjusted by changing the inclination angle of the cam plate by adjusting the pressure in the crank chamber, and when said first external refrigerant circuit is shut off by said control means, an internal refrigerant circulation circuit is formed within said compressor, which circulation circuit starts from the discharge chamber and returns to the discharge chamber through the crank chamber and the suction chamber.  
     
     
         11 . The vehicular air conditioner according to  claim 10 , wherein when the discharge displacement of the compressor becomes a minimum, said first external refrigerant circuit is shut off in association therewith.  
     
     
         12 . The vehicular air conditioner according to  claim 10 , wherein while the refrigerant is circulating in said internal refrigerant circulation circuit, when a physical quantity that indicates a heat-generation state of the compressor or a physical quantity that influences heat-generation state of the compressor shows deterioration of the heat-generation state of the compressor, said second external refrigerant circuit is opened.  
     
     
         13 . The vehicular air conditioner according to  claim 12 , wherein said control means includes: 
 an electromagnetic control valve that selectively opens or closes said second external refrigerant circuit by an electric power supply control from the outside,    a sensor, which detects the physical quantity that exhibits a heat-generation state of the compressor or the physical quantity that influences the heat-generation state of the compressor, and    a controller that commands said electric control valve to open the second external refrigerant circuit when the detected information from said sensor shows deterioration of the heat-generation state of the compressor while said refrigerant circulates in said internal refrigerant circulation circuit.    
     
     
         14 . The vehicular air conditioner according to  claim 12 , wherein said control means includes a sensing member, which senses the physical quantity that indicates the heat-generation state of the compressor or the physical quantity that influences the heat-generation state of the compressor, and operates, said control means opens said second external refrigerant circuit by the operation of said sensing member when a heat-generation state of the compressor deteriorates while a refrigerant circulates in the internal refrigerant circuit.  
     
     
         15 . The vehicular air conditioner according to  claim 1 , wherein carbon dioxide is used as said refrigerant.  
     
     
         16 . The vehicular air conditioner according to  claim 1 , wherein said second external refrigerant circuit includes a refrigerant-cooling heat exchanger.  
     
     
         17 . The vehicular air conditioner according to  claim 16 , wherein said refrigerant-cooling heat exchanger is a low-pressure side heat exchanger of an internal heat exchanging device used in said first external refrigerant circuit.  
     
     
         18 . A vehicular air conditioner comprising: 
 a compressor directly connected to a drive source of a vehicle to permit power transmission, wherein the compressor compresses a refrigerant by being at all times driven by the drive source, wherein the compressor includes a discharge chamber, a suction chamber, a cam plate, and a crank chamber that accommodates the cam plate, a discharge displacement is adjusted by changing the inclination angle of the cam plate by adjusting the pressure in the crank chamber;    a first external refrigerant circuit including a condenser, a pressure reducing device, and an evaporator;    a second external refrigerant circuit, which connects a discharge chamber to a suction chamber of said compressor at the outside of said compressor and permits the circulation of the refrigerant that is not involved in air conditioning; and    control means, which selectively open or close said first external refrigerant circuit and said second external refrigerant circuit, respectively;    wherein, when said first external refrigerant circuit is shut off by said control means, an internal refrigerant circulation circuit is formed within said compressor, which circulation circuit starts from the discharge chamber and returns to the discharge chamber through the crank chamber and the suction chamber.    
     
     
         19 . The vehicular air conditioner according to  claim 18 , wherein said second external refrigerant circuit partially shares its circuit with said first external refrigerant circuit, and said second external refrigerant circuit includes a bypass passage, which connects the discharge chamber to the suction chamber of said compressor in a state where the condenser or the evaporator in said first external refrigerant circuit is bypassed.  
     
     
         20 . The vehicular air conditioner according to  claim 19 , wherein said first external refrigerant circuit includes an accumulator between the evaporator and the suction chamber of said compressor and a low-pressure side of said bypass passage is connected to said first external refrigerant circuit between the evaporator and the accumulator.  
     
     
         21 . The vehicular air conditioner according to  claim 19 , wherein said first external refrigerant circuit includes an internal heat exchanging device, said internal heat exchanging device having a high-pressure side heat exchanger through which the refrigerant flows from the discharge chamber of the compressor to the pressure reducing device, and a low-pressure side heat exchanger through which the refrigerant flows from the evaporator to the suction chamber of the compressor, heat exchange being executed between the high-pressure side and low-pressure side heat exchangers, and that the low-pressure side of said bypass passage is connected between the evaporator and the low-pressure side heat exchanger of the internal heat exchanging device in said first external refrigerant circuit.  
     
     
         22 . The vehicular air conditioner according to  claim 19 , wherein the high-pressure side of said bypass passage is connected between the condenser and the pressure reducing device, in said first external refrigerant circuit.