Air conditioner

Abstract

An air conditioner for air conditioning the interior of a compartment having a compressor, an electric motor, a detection device, a rotation speed sensor, and a controller is provided. The compressor compresses refrigerant gas and changes the displacement. The electric motor drives the compressor, and is capable of rotating at a constant reference rotation speed. The detection device detects information related to the thermal load on the air conditioner. The rotation speed sensor detects the rotation speed of the motor. The controller computes a target torque of the compressor at the reference rotation speed of the motor based on the thermal load information detected by the detection device, and computes an input current value to be supplied to the motor. The input current value corresponds to the target torque. The controller drives the motor according to the computed input current value, and controls the displacement of the compressor such that the detected rotation speed of the motor matches the reference rotation speed.

1 . An air conditioner for air conditioning the interior of a compartment, comprising: 
 a compressor, wherein the compressor compresses refrigerant gas and changes the displacement;    an electric motor for driving the compressor, wherein the motor is capable of rotating at a constant reference rotation speed;    a detection device for detecting information related to the thermal load on the air conditioner;    a rotation speed sensor for detecting the rotation speed of the motor; and    a controller, where-in the controller computes a target torque of the compressor at the reference rotation speed of the motor based on the thermal load information detected by the detection device, and computes an input current value to be supplied to the motor, the input current value corresponding to the target torque, wherein the controller drives the motor according to the computed input current value, and wherein the controller controls the displacement of the compressor such that the detected rotation speed of the motor matches the reference rotation speed.    
     
     
         2 . The air conditioner according to  claim 1 , wherein the air conditioner is mounted on a vehicle to air condition the passenger compartment of the vehicle and is also driven by an engine of the vehicle.  
     
     
         3 . The air conditioner according to  claim 2 , wherein the compressor includes a housing, wherein the housing supports a rotary body, the rotary body being rotated by the engine, and wherein the electric motor is located radially inward of the rotary body.  
     
     
         4 . The air conditioner according to  claim 1 , further comprising a control valve for changing the displacement of the compressor.  
     
     
         5 . The air conditioner according to  claim 4 , wherein the compressor has a suction chamber, a discharge chamber, a crank chamber, and a supply passage, the supply passage connecting the discharge chamber with the crank chamber, wherein the control valve is located in the supply passage to adjust the opening degree of the supply passage.  
     
     
         6 . The air conditioner according to  claim 5 , further comprising a refrigerant circuit including the compressor and an external refrigerant circuit, wherein the control valve includes a pressure sensing mechanism, and wherein the pressure sensing mechanism detects the pressure difference between two pressure monitoring points set along the refrigerant circuit.  
     
     
         7 . The air conditioner according to  claim 6 , wherein the external refrigerant circuit includes a condenser, an expansion valve, and an evaporator.  
     
     
         8 . The air conditioner according to  claim 6 , wherein the control valve includes: 
 a valve body for adjusting the opening degree of the supply passage; and    an actuator, wherein the actuator changes force applied to the valve body based on a command from the controller, thereby changing an intended pressure, the intended pressure being used as a reference when the pressure sensing mechanism determines the position of the valve body.    
     
     
         9 . An air conditioner for air conditioning the passenger compartment of a vehicle having an engine, comprising: 
 a compressor, wherein the compressor compresses refrigerant gas and changes the displacement;    a one-way clutch, wherein, when the engine is running, the one-way clutch selectively transmits the power of the engine to the compressor;    an electric motor for driving the compressor when the engine is not running, wherein the motor is capable of rotating at a constant reference rotation speed;    a detection device for detecting information related to the thermal load on the air conditioner;    a rotation speed sensor for detecting the rotation speed of the motor; and    a controller, wherein the controller computes a target torque of the compressor at the reference rotation speed of the motor based on the thermal load information detected by the detection device, and computes an input current value to be supplied to the motor, the input current value corresponding to the target torque, wherein the controller drives the motor according to the computed input current value, and wherein the controller controls the displacement of the compressor such that the detected rotation speed of the motor matches the reference rotation speed.    
     
     
         10 . The air conditioner according to  claim 9 , wherein the compressor includes a housing, wherein the housing supports a rotary body, the rotary body being rotated by the engine, and wherein the electric motor is located radially inward of the rotary body.  
     
     
         11 . The air conditioner according to  claim 9 , further comprising a control valve for changing the displacement of the compressor.  
     
     
         12 . The air conditioner according to  claim 9 , wherein the compressor has a suction chamber, a discharge chamber, a crank chamber, and a supply passage, the supply passage connecting the discharge chamber with the crank chamber, wherein the control valve is located in the supply passage to adjust the opening degree of the supply passage.  
     
     
         13 . The air conditioner according to  claim 12 , further comprising a refrigerant circuit including the compressor and an external refrigerant circuit, wherein the control valve includes a pressure sensing mechanism, and wherein the pressure sensing mechanism detects the pressure difference between two pressure monitoring points set along the refrigerant circuit.  
     
     
         14 . The air conditioner according to  claim 13 , wherein the external refrigerant circuit includes a condenser, an expansion valve, and an evaporator.  
     
     
         15 . The air conditioner according to  claim 13 , wherein the control valve includes: 
 a valve body for adjusting the opening degree of the supply passage; and    an actuator, wherein the actuator changes force applied to the valve body based on a command from the controller, thereby changing an intended pressure, the intended pressure being used as a reference when the pressure sensing mechanism determines the position of the valve body.