JPS55132318A - Control system for switching inner-outer air mode of auto air conditioner in automobile - Google Patents

Abstract

PURPOSE:To obtain the highest efficiency of an auto air conditioner, by detecting the temperatures of outside air and room air when started a cool down operation, performing the work of comparison and decision on the basis of their detected in formations and selecting the mode of outside air conduction or inner air circulation in accordance with a result from the above process. CONSTITUTION:Temperature signals from a room temperature sensor 13 and outside air temperature sensor 12 are converted into digital signals by an A/D converter 20c and input to a computer 20. The computer 20 performs the work of comparing the both temperature signals and deciding its comparison value and the decision value for discriminating whether to circulate inner air or induct outside air at the time of beginning a cool down operation. When the comparison value is higher than the decision value, the computer 20 actuates a relay 18 to permit an electric current to flow in a solenoid valve 17. The solenoid valve 17 causes atmospheric air to be inducted into a diaphragm chamber 15a of a negative pressure actuator 15. When the comparison value is equal to the decision value or less, the relay 18 ceases its operation to transmit a negative pressure to an inner and outer air switching damper 4 through a rod 16.