Numerical Assessment of a New Hydro-Pneumatic Suspension System for Motorcycles

Abstract

This work investigates an innovative hydro-pneumatic suspension system that was recently developed for possibly enhancing the performance of wheeled road vehicles, particularly motorcycles. The device exhibits a highly non-linear behavior, and in particular a strongly regressive spring rate, due to its architecture (featuring a hydro- pneumatic spring and a coil spring arranged in series). Multibody models are implemented and simulated for a preliminary assessment of its actual benefits and/or drawbacks with respect to common suspension systems. As a starting point of the research, this work focuses on the in-plane dynamics, and in particular on a condition of straight running at constant speed. The load fluctuations on the rear wheel (grip) as well as the velocity of the suspended mass (comfort) under different road inputs at various speeds are analyzed. The numerical results confirm the hydro-pneumatic suspension system as a promising device.