The present invention relates generally to vehicular suspension systems and, in a preferred embodiment thereof, more particularly provides a liquid spring vehicular suspension system in which the spring and damping characteristics of each liquid spring are computer adjusted, during vehicle operation, in response to sensed variations in liquid spring and vehicle operating parameters.
In the past, various proposals have been made for replacing the conventional hydraulic shock absorber and exterior coil spring assemblies in vehicular suspension systems with more compact devices known as liquid springs. A liquid spring basically comprises a cylindrical housing having an internal chamber with a compressible liquid therein, a piston reciprocably disposed in the chamber, and a rod structure axially movable into and out of the chamber, secured to the piston, and having an outer longitudinal portion projecting outwardly of one of the housing ends. With the liquid spring operatively interconnected between the vehicle frame and an associated wheel support structure, the compressible liquid within the liquid spring generates both spring and damping forces in the suspension system in response to relative axial translation between the rod structure and housing of the liquid spring caused by relative vertical displacement between the wheel and the frame. A more detailed description of the general structure and operation of a liquid spring incorporated in a vehicular suspension system may be found in U.S. application Ser. No. 941,289, entitled "FLUID SUSPENSION SPRING AND DAMPER FOR VEHICLE SUSPENSION SYSTEM", which has been incorporated herein by reference.
Various mechanisms have been proposed for selectively adjusting the spring force and/or damping force characteristics of liquid springs to settings which remain essentially constant during vehicle operation until readjusted when the vehicle is at rest. Thus, these essentially fixed spring force and damping force characteristics represent at best predetermined compromise settings adapted to handle an often wide range of road conditions and vehicle operational inputs (such as steering input, braking forces, vehicle speed and the like) encountered during operation of the vehicle.
It can be seen that it would be desirable to provide a liquid spring vehicular suspension system in which the spring force and damping force characteristics of the liquid springs are automatically adjusted, during vehicle operation, to compensate for variations in both road conditions and vehicle operational inputs, or any combination thereof. It is accordingly an object of the present invention to provide such a system.