New Suspension Design for Heavy Duty Trucks: Design Considerations 2003-01-3428
The present paper presents design considerations for a new tandem suspension system equipped with hydro-pneumatic components. The theory of the new suspension and its configuration were presented in a previously published SAE paper, . In this design, most of the vertical motions were transformed into horizontal motions through two bell cranks.
A hydraulic actuator is installed horizontally between the bell cranks and connected to an accumulator (gas spring) via a flow constriction (damper). Incorporating of hydro-pneumatic components in the new suspension system exhibits simple and applicable design. Moreover, further developments including active or semi-active vibration control systems, can be applied directly using the existing hydro-pneumatic components.
Mathematical models are constructed to simulate the vehicle ride dynamics. Equations of motion are generated considering a conventional passive suspension (four springs tandem suspension) and the new designed suspension system. Random responses, due to random road excitations, have been calculated considering several vibration isolation parameters and road roughness conditions. Comparison with a conventional four spring tandem suspension showed that the new suspension system offers 70 % lower root mean square body vertical acceleration and 9.22 % lower root mean square dynamic tire loads.