Air conditioning system for vehicles

Claim 1

An air conditioning system for a vehicle, said vehicle having a compartment, and a windowpane, comprising: duct means having at an upstream end thereof an air intake section and at a downstream end thereof an air blowoff section in communication with the compartment of the vehicle; a refrigerating cycle including a compressor of a variable capacity type, for cooling and dehumidifying air flowing through said duct means; synthetic signal arithmetic means for computing a synthetic signal based on at least an indoor-air temperature and an outdoor-air temperature which represent a thermal load, except for a mist on the windowpane of the vehicle; detecting means for detecting the mist on the windowpane of the vehicle; capacity arithmetic means connected to said synthetic signal arithmetic means for computing a capacity of said compressor required for air conditioning control, based on said synthetic signal; auxiliary capacity arithmetic means connected to said detecting means for computing a capacity of said compressor required for demist control for removing said mist, only based on an output from said detecting means; comparator means connected to said capacity arithmetic means and to said auxiliary capacity arithmetic means for comparing said capacity required for said air conditioning control and said capacity required for said demist control with each other; and control means connected to said comparator means for controlling the capacity of said compressor so as to be brought to the greater one of said capacities compared by said comparator means.