A CONTROL DEVICE FOR A VARIABLE DISPLACEMENT COMPRESSOR IN AN AIR CONDITIONING SYSTEM

摘要

A scroll-type compressor (1) includes a magnetic clutch (8) and variable-displacement device (9). The compressed gas is liquefied in a condenser (2) and accumulated in a receiver and dryer (3). Dehumidified liq. is delivered via a thermostatic expansion valve (4) to an evaporator (5) acting as a heat exchanger in conjunction with the passenger compartment fan (7). A control circuit (10) connected by a switch (S) compares the cooled air temp. with a first predetermined temp. and operates the clutch (8) when the temp. needs to be reduced. When the air temp. exceeds a second predetermined temp. the variable-displacement device (9) is operated to increase the cooling capacity. The compressor's operation rate is compared with a predetermined ideal, and cooling capacity is reduced to the min. required to meet the load.