Electric, variable damping vehicle suspension

Abstract

An electric, variable damping suspension for a motor vehicle comprises a three phase rotary electric alternator, a ball screw and nut apparatus connecting the sprung and unsprung masses and driving the alternator in alternating rotary directions as the sprung and unsprung masses oscillate relative to each other, a rectifier bridge for converting the three phase alternator output to a single DC current, an electric load, and a switch for controlling the application of the DC current to the electrical load. Circuits determine the times of consecutive zero crossings of each phase and update therefrom a signal indicative of the magnitude of rattle space velocity. The circuits further determine, from the identities of the alternator phases of successive zero crossings of any phase compared with stored expected consecutive phase identities, the direction of the rattle space velocity. A chopping control circuit is responsive to the magnitude and direction signals of rattle space velocity to control the switch in a variable duty cycle operation to vary the average current through the electric load and thus the damping force of the suspension. An additional circuit may be responsive to the current through the electric load to generate a signal indicative of the actual damping force of the suspension.

Dependencies are inferred from the claim text.