Automatic temperature control system for vehicle air conditioners

Abstract

An automatic temperature control system for a vehicle air conditioner including a cool air supply mechanism having an air flow control device, an air flow dividing device for dividing a cool air flow supplied from the cool air supply mechanism into a primary flow and a secondary flow, a heat source for heating the primary flow, and a mixing mechanism for mixing the primary flow as warmed past the heat source, and the secondary air which remains cool, with each other. The control system comprises a first circuit for sensing for output as a first signal an air temperature within the interior of a vehicle, a second circuit for sensing for output as a second signal an air temperature outside the vehicle interior, a third circuit for providing a third signal corresponding to a preset temperature, a fourth circuit interlocked with the flow dividing device so as to output as a fourth signal the flow-dividing ratio thereof, a fifth circuit for providing a fifth signal upon a comparison of the first signal with the third signal, a sixth circuit for providing a sixth signal upon a comparison of the second signal with the third signal, and a seventh circuit for providing a seventh signal to determine the mixing ratio of the primary flow and the secondary flow upon a comparison among the fourth, fifth and sixth signals, the air flow control device being controlled by the fifth signal, and the air flow dividing device being controlled by the seventh signal. The automatic temperature control system is of low noise and adequately counteracts temperature changes within the vehicle interior.