Apparatus for computing recognized value of amount of solar radiation in automobile air-conditioning system

This invention concerns an apparatus for computing a recognized value as one of the control elements for an automobile air-conditioning system, which apparatus performs the computation of the recognized value by a procedure which comprises detecting an amount of solar radiation with the aid of solar radiation amount detection means, forming a decision as to the trend of variation of the amount of solar radiation with the aid of comparison means, and performing an operation of integration of a recognized value of the amount of solar radiation with the aid of arithmetic operation means by using a relatively small time constant when the decision is that the amount of solar radiation is on the upward trend or a relatively large time constant when the decision is the opposite. The air conditioning, therefore, is controlled so as to follow the variation in the amount of solar radiation when this amount is on the upward trend or to remain in the present status when the amount is on the downward trend. The control effected in this manner enables the occupants of an automobile to enjoy highly satisfactory feeling of air conditioning.