Vehicular suspension control system with variable damping characteristics depending upon road condition and vehicle speed

A suspension control system for an automotive vehicle comprising:

• a damper means interpositioned between a vehicle body and a road wheel for absorbing, at least in part, relative displacement between the vehicle body and the road wheel, said damper means having damper characteristics selectably variable between a first weaker damping characteristics mode and a second stronger damping characteristics mode;
• a first sensor producing a first sensor signal, the amplitude and frequency of which correspond to the amplitude and frequency of vibrations of the vehicle body;
• a second sensor adapted to produce a second sensor signal indicative of a vehicle speed;
• a filter means receiving said first sensor signal and outputting a filter signal representative of the amplitude of a specific frequency range of said sensor signal;
• a comparator means receiving said filter signal and comparing the amplitude thereof with a reference value, said comparator means producing a comparator signal when the filter signal value is greater than the reference value;
• a reference signal generator for transmitting said reference signal to said comparator means, said reference signal generator being responsive to said second sensor signal to vary the value of said reference signal based thereon;
• a controller associated with said damper means for normally operating the latter in said first softer damping characteristics mode, said controller being responsive to said comparator signal to operate said damper means in said second harder damping characteristics mode.