Abstract: A control unit of a vehicle control system estimates running-condition of a vehicle for a predetermined estimation period. A fuel-amount estimating portion estimates an engine condition related to a cooling efficiency, based on the estimated running condition. The control unit estimates multiple possible control patterns and calculates evaluation values related to the cooling efficiency for respective cases, in which a compressor is operated in accordance with each of the control patterns. The control unit selects one of control patterns to actually operate the compressor in accordance with the selected control pattern, so that fuel consuming amount can be reduced.