Abstract
Recently we experimentally investigated the dynamic performances of the frontal suspension of an automobile equipped with passive oil and colloidal dampers. Since in the case of passive absorbers the damping ratio cannot be adjusted according to the excitation level of the rough road, in such tests, conducted on a relatively inexpensive car, the ride-comfort factor varied in the range 10-1000. Consequently, during long riding intervals, the passengers felt sick and the driver's concentration was diminished. As countermeasure, in this work an active-control colloidal damper for car suspension is proposed. Such device can be mounted on the car without a compression helical spring working in parallel with it, and its damping rate can be controlled by adjusting the pre-pressurization level of the colloid inside the cylinder. First, the active colloidal suspension was dynamically tested on a classical fatigue machine and the variation of the damping coefficient versus the applied pre-pressure was determined. Then, the active colloidal suspension was mounted on a real car and travel tests were performed on a road with half-sinusoidal steps made of asphalt. Ride-comfort factor, and the sensitivity of the active-control suspension were experimentally evaluated.
