Abstract: An electronic fluid suspension system having longitudinal acceleration sensor, acceleration difference calculation means and vehicle attitude control means in addition to other fluid flow control components known in the conventional suspension system. In this system, the vehicle attitude is controlled responsive to the difference between a maximum acceleration and a minimum acceleration detected within a predetermined time interval. When dive or squat of the vehicle body is anticipated by the difference, vehicle attitude control is performed, without inappropriately responding to a momentary change in the acceleration. After the vehicle attitude control, a return control is performed to restore the original attitude and, further, a vehicle attitude correction control is performed responsive to a difference in actual front/rear heights and corresponding original heights.

Abstract: An air pressure circuit comprising a compressor cylinder which is divided into two chambers by a slidable piston, a suction port and an exhaust port each, having a valve and mounted on one chamber of the cylinder, inhaling air of a pressure higher than that of atmospheric air form the suction port and exhausting the piston-compressed air from the exhaust port. The air pressure in the side of suction port is introduced from the other chamber of the cylinder.

Abstract: An electronically controlled fluid suspension system for preventing the lateral roll of a vehicle computes a predetermined estimated lateral acceleration based on the running speed and the difference between the maximum steering angle and the minimum steering angle within a predetermined period. The supply and discharge of the air to and from the air springs is rapidly controlled corresponding to the estimated lateral acceleration so as to prevent the vehicle from rolling due to the steering operation. Moreover, the electronically controlled fluid suspension system computes a predetermined target vehicle height based on the lateral acceleration. After the air is supplied and discharged to and from the air springs and the increase of the lateral acceleration is stopped, the vehicle height is restored regardless of the external disturbance, by controlling the supply and discharge of the air corresponding to the vehicle height difference between the target vehicle height and the actual vehicle height.

Abstract: A vehicle fluid suspension circuit has an efficient cross-sectional area of the high pressure supply line is smaller than that of the low pressure exhaust line. The fluid supply and discharge speed can be equalized so that the vehicle height increasing speed and the vehicle height decreasing speed are equalized with each other, and the ride comfort is improved. Furthermore, the vehicle suspension circuit has two lines from fluid suspension to low pressure reserve tank are provided during fluid exhaust. A simplified construction can vary a speed of exhausted fluid from fluid suspension. Feeding and exhausting speeds, computation for the valve opening and closing time intervals is improved to be quite simple, and quick control is attained.

Abstract: An electronically controlled fluid suspension system detects an average longitudinal or lateral acceleration within a predetermined period, computes an acceleration difference between a maximum average acceleration and a minimum average acceleration. Based on the acceleration difference, an estimated longitudinal or lateral acceleration is computed. In response to the estimated longitudinal or lateral acceleration, computed are a height-raising quantity of a lowered portion of a vehicle and a height-lowering quantity of a raised portion thereof. The supply and release of a fluid to and from fluid springs is rapidly controlled so that the height-raising quantity of the lowered portion of the vehicle is less than the height-lowering quantity of the raised portion thereof. The electronically controlled fluid suspension system, thus, prevents the vehicle from inclining due to changes in driving status, and enhances a road-adherence ability on an uneven road as well as a steering stability.

Abstract: An electronically controlled fluid suspension system for adjusting a vehicle's attitude rapidly controls the vehicle height: by providing and blocking the fluid communication between fluid springs and reserve tanks; and by shifting the damping force of shock absorbers to a higher degree in response to the change of the vehicle height. As a result, it can avoid the late control of the vehicle height and prevent the vibration of the vehicle body due to the vehicle height's adjustment, thereby enhancing riding comfort.

Abstract: A vehicle fluid suspension circuit comprising fluid sources provided to the front and rear sides of a vehicle, front and rear side paths connecting the front and rear side fluid sources and fluid suspensions of right and left wheels of the respective sides and providing valves between the resepective fluid sources and fluid suspensions of respective wheels and a front-to-rear path having an effective sectional area which is smaller than the effective sectional areas of the front side path and rear side path, respectively, and connecting the front side fluid source with the rear side fluid source.

Abstract: A vehicle air suspension circuit having air suspensions for wheels and an air supply device which increases pressure of air taken from an air intake port and supplies the air to the air suspension. Moreover, this vehicle air suspension circuit is made up of a tank which receives the air discharged from the air suspension and is kept at the pressure higher than the atmospheric air pressure and a changeover valve which is provided to the air intake port of the air supply device and selects atmospheric air or the air in the tank as the intake air.

Abstract: An electronic controlled gas suspension system for realizing rapid control of the vehicle attitude and uniform actions of air springs. In this suspension system, gas states in plural reserve tanks are detected by gas state detection means to energize/deenergize communication means for communicating/discommunicating the reserve tanks one another when a pressure difference among the reserve tanks is determined to attain a predetermined value, so that the air states in the plural pressure tanks can be controlled to be equal.

Abstract: Provided is an electronic controlled air suspension system consuming less energy in preparing air in the high pressure reserve tank and low pressure reserve tank. Until the total sum of pressures of high pressure reserve tank and low pressure reserve tank reaches a predetermined first value, the pressure in the low pressure reserve tank is preferably controlled. After that, air in the low pressure reserve tank is supplied to the high pressure reserve tank until the pressure in the high pressure reserve tank reaches a desired value. In another feature of the invention, air is rapidly charged to the high pressure reserve tank regardless of the above procedure when a rapid charging to the reserve tanks are needed. This ensures continuous operations of rapid vehicle attitude control.

Abstract: In a gas suspension system for controlling a body attitude of a vehicle, a controller drives a compressor and control valves to supply compressed air to a high pressure reserve tank. After enough air is supplied to the high pressure reserve tank, the compressor is stopped and the control valves are shut, whereby high pressure air remains at the delivery port of the compressor. Then a specially provided connection control valve is opened for a predetermined period in order to put the delivery port of the compressor in communication with a low pressure reserve tank. The pressure at the delivery port thus can be decreased, resulting in less torque needed to start the compressor.