Displacement control system for variable displacement compressor

Abstract

A discharge displacement control system (A) of a variable displacement compressor has target pressure setting means (402A), discharge pressure detection means (500), and electric current regulation means (404, 406). The target pressure setting means (402A) sets a target of either the pressure in a suction chamber or the pressure in a crank chamber based on a target air temperature at the evaporator exit detected by means (510) for detecting the air temperature at the evaporator exit and on a target air temperature at the evaporator exit set by means (512) for setting a target air temperature at the evaporator exit. The discharge pressure detection means (500) detects the pressure of refrigerant in a high-pressure region. The electric current regulation means (404, 406) regulate, based on both the pressure of the refrigerant in the high-pressure region detected by the discharge pressure detection means (500) and the target pressure set by the target pressure setting means (402A), electric current supplied to a solenoid (316) of a displacement control valve.

Description

technical field [0001] The invention relates to a capacity control system of a variable capacity compressor suitable for an air conditioning system. Background technique [0002] For example, a reciprocating type variable capacity compressor used in a vehicle air-conditioning system includes a casing, and a discharge chamber, a suction chamber, a crank chamber, and a cylinder bore are formed inside the casing. A swash plate is connected in a tiltable form to a drive shaft extending in the crank chamber, and a conversion mechanism including the swash plate converts rotation of the drive shaft into reciprocating motion of a piston disposed in the cylinder bore. The reciprocating motion of the piston executes the process of sucking the working fluid from the suction chamber into the cylinder bore, compressing the sucked working fluid, and discharging the compressed working fluid to the discharge chamber. [0003] The stroke length of the piston, that is, the discharge capacity...

AI Technical Summary

Problems solved by technology

Therefore, the miniaturization of the diaphragm is also limited

[0017] In addition, in an air-conditioning system using carbon dioxide as a refrigerant, since the pressure of the refrigerant is extremely high, it is difficult to use pressure-sensitive components such as bellows to detect the suction pressure and perform feedback control on the discharge capacity.

[0018] On the other hand, when the vehicle is idling, in order to achieve stable control of the engine speed, it is necessary to adjust the load of the variable capacity compressor, but the capacity control method that takes the suction pressure as the control object does not realize this adjustment.

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