A vehicle suspension system includes a cylinder device, provided between a vehicle body member and a vehicle wheel member for the vehicle body member, in which suspension characteristics are changed by controlling hydraulic fluid supply for the cylinder device. A vehicle height displacement detecting device detects a vehicle height displacement, and a vehicle height control device receives a signal from the vehicle height displacement detecting device to control the hydraulic fluid supply for the cylinder device to thereby obtain a target vehicle height displacement in accordance with a height control sensitivity. A sensitivity change device changes the height control sensitivity in accordance with a predetermined condition so as to change the supply of the hydraulic fluid for the cylinder device. A warp control cooperate and a height control are optimized.

Vehicle height control for a motor vehicle which has height adjusting means for each of wheel suspensions and which is stationary on a distorted road surface. Height control is carried out for either one of the front wheel suspension pair and the rear wheel suspension pair to attain a reference vehicle height for both the left and right wheels of the one pair whereby the vehicle part having said one pair assumes an attitude parallel to the inclination of the road surface in a direction transverse to the vehicle part. For the other pair of the wheel suspensions, height control is carried out such that the opposite part of the vehicle with the other pair of the wheel suspension will assume an attitude substantially equivalent to the attitude of the first mentioned vehicle part, whereby a good balance is obtained between the contact loads of the wheels.

A height regulation system for an automotive vehicle to generally adjust a vehicular height level within a predetermined height range includes a variable pressure chamber, in which the fluid pressure is adjusted to adjust the relative distance between the vehicular body and a vehicular wheel. The system includes a control circuit including a sensor for monitoring vehicular height for detecting an actual vehicular height beyond the predetermined height range for triggering height adjustment operation. The control circuit limits the variation range of the fluid pressure within a predetermined range so as to avoid excess adjustment of the pressure at any vehicular condition.

In a motor vehicle having a vehicle height adjusting device, wherein the height of each suspension is controlled so as to attain a set reference vehicle height, reaction forces of respective suspensions are detected and a difference between the detected reaction forces is calculated according to a formula, while the vehicle is stationary or is being driven straight. When the difference exceeds a predetermined value, it is determined that there are imbalances of the road surface contact loads of the wheels. Upon the determination of imbalances, the reference vehicle height is increased for some suspensions and decreased for other suspensions to eliminate the imbalances. The determination of imbalances is made when a value given by a formula including the integrated values for the suspensions exceeds a predetermined value, and then reference vehicle height is increased and decreased for the suspensions to eliminate the imbalances.

A mechanism is provided for lowering the height of the front part of a motor vehicle. A radar sensor is provided to sense the proximity of an adjacent vehicle. A signal is passed to a control unit which responds when a potential accident situation is detected. An output passes to a valve unit which is actuated to permit gas from an inflatable element to escape through a nozzle. As the gas escapes the element reduces in length, and a lowering housing element connected to a wheel of a vehicle moves upwardly into an upper housing element which is fixed to part of the structure of the vehicle. Thus, the front part of the vehicle is lowered so that the bumper on the vehicle is at an appropriate height.