RIDE PERFORMANCE EVALUATION OF AIR AND HYDRO-PNEUMATIC SPRINGS OF SUSPENSION SYSTEM

In order to evaluate the performance of the air spring of the suspension system in comparison with the hydro-pneumatic suspension system, a mathematical model of air and hydro-pneumatic springs of suspension systems is established based on their nonlinear characteristics. The performance of the air suspension system is evaluated and compared to the hydro-pneumatic suspension system through two objective functions such as the weighted root mean square (rms) of acceleration responses of the vertical direction of the vehicle body (awb) and dynamic load coefficient (DLC). The obtained results indicate that the awb and DLC values with the air suspension system reduce by 11.87 % and 41.46% in comparison with the hydro-pneumatic suspension system when the vehicle moves on the ISO class B road surface at the vehicle speed of 60 km/h and full load. Finally, the performance of the air suspension system is evaluated and compared to the hydropneumatic suspension system under different operating conditions of vehicle and the evaluation results indicate that the ride performance of the air suspension systems has better than the hydro-pneumatic suspension system.