Displacement control method and apparatus for variable displacement compressor

A displacement control device for a variable displacement compressor used in a vehicle air conditioner, wherein the compressor is driven by an engine and varies the displacement in accordance with the pressure in a crank chamber, the control device comprising:

• a control valve for controlling the pressure in the crank chamber, the control valve including:
• a valve body;
• and
• an electromagnetic actuator for applying a force to the valve body, wherein the magnitude of the force corresponds to a value of a current supplied to the actuator;
• a power source for supplying the current to the actuator;
• a drive circuit for adjusting the current supplied to the actuator;
• a switch device located between the actuator and the power source;
• and
• a controller for setting a target value of the current supplied to the actuator in accordance with an external condition, wherein, when the target value is changed and a predetermined time elapses, the controller instructs the drive circuit to supply current to the actuator in accordance with the new target value and controls the switching of the switch device such that the current is intermittently supplied from the power source to the actuator before setting the current to the new target value during the predetermined time.

A method for controlling a displacement control device of a variable displacement compressor used in a vehicle air conditioner, wherein the compressor is driven by an engine and changes the displacement in accordance with the pressure in a crank chamber, the method comprising:

• controlling the pressure in the crank chamber with a control valve, wherein the control valve includes a valve body, an electromagnetic actuator for applying a force to the valve body, wherein the magnitude of the force corresponds to the value of current supplied to the actuator;
• determining the target value of current supplied to the actuator in accordance with an external condition;
• supplying the current to the actuator;
• and
• intermittently supplying the current to the actuator when the target value is changed before the current is adjusted to the new target value.