Compressor unit used in closed cycle cooling system for road vehicle air conditioner has piezoelectric actuator stack imparting high- frequency oscillations to piston in working chamber

摘要

The piezoelectric actuators in the stack (5) are made of a lead-titanium-zirconate mixture with 60% lead. Each layer is 200 mu thick and all the layers are connected in parallel. A drive voltage of 400 V is connected across the actuator terminals and oscillator switched to impart high-frequency oscillations to a piston (6) in a working chamber (3). The piston may perform 30,000 suction and compression strokes per minute. A double housing (1) surrounds the actuator stack and has an inlet (19) for carbon dioxide gas which flows through the annular gap (18) to an outlet (20), a bypass line (21) and a flap inlet valve (8). The carbon dioxide flows out through a flap valve (9). There is a gap (2,12) between the outside diameter of the actuator stack and the inside diameter of the housing.