Abstract: In a damping force control system for switching over a shock absorber in the suspension of a vehicle from a low damping force operation to a high damping force operation when a vehicle height difference exceeds a determinate limit value, the shock abosrber is switched over from the low damping force operation to the high damping force operation after the lapse of a delay period so that the shock absorber is continually maintained at the high damping force operation from a time point at which the vehicle height difference generally reaches a peak amplitude of its variation for a time duration which is increased as a peak amplitude of the vehicle height difference exceeding the determinate limit value increases.

Abstract: In a damping force control system for switching over a shock absorber in the suspension of a vehicle from a low damping force operation to a high damping force operation when a vehicle height difference exceeds a certain limit value, the frequency of the vehicle height difference exceeding the certain limit value is counted for each certain cycle period, and the shock absorber is controlled to provide the high damping force operation for a time duration in each cycle period, the ratio of the time duration to the cycle period being varied in accordance with the frequency so that the ratio is increased along with an increase of the frequency.