Abstract: In order to improve the ride performance of the off-road vehicle, a twin-accumulator hydro-pneumatic suspension is proposed. Its structure is analyzed, its working principle is described, and its mathematic model is built. Based on the parameters of an off-road vehicle, 1/4 vehicle vibration model is built. Through simulation, the influence of each parameter of twin-accumulator hydro-pneumatic suspension on the vehicle body acceleration, dynamic deflection of suspension and relative dynamic load of wheel is studied respectively. The results indicate that the interior accumulator has greater influence on the relative dynamic load of wheel than the outside accumulator, and the outside damper has greater influence on the ride performance than the damping hole on the piston. Through optimization of the results, the parameters of twin-accumulator hydro-pneumatic suspension are determined. The ride performance of the vehicle with twin-accumulator hydro-pneumatic suspension is compared with those of vehicles with passive hydro-pneumatic suspension and with coil spring in both time domain and frequency domain. The results indicate that the adoption of twin accumulator system can obviously improve the ride performance of vehicle, and it is more suitable for off-road vehicle.

Key words: Hydro-pneumatic suspension, Off-road vehicle, Ride performance, Twin-accumulator