Implementation and Experimental Study of a Novel Air Spring Combined with Hydraulically Interconnected Suspension to Enhance Roll Stiffness on Buses

Air spring due to its superior ride comfort performance has been widely used in distance passenger transporting vehicles. Since the requirements for ride comfort and handling performance are contradict to each other, handling performance and even roll stability are sacrificed to some extent to obtain good ride comfort. Due to the complex terrain and limited manufacturing level, in the past several years, bus rollover accidents with serious casualties have been reported frequently and bus safety has attracted more and more attention from bus manufacturers in China. On one hand the bus standards have to be raised, and on the other hand, novel solutions which can effectively improve the roll stability of air spring bus are needed to replace the inadequacy of anti-roll bars. This paper starts from experiment-based system parameter estimation to identify the handling issues of the new bus and redefine the design scope, then a combination design of air spring with an anti-roll hydraulically interconnected suspension is proposed, aiming to improve the cornering stability, ride comfort in roll direction, while maintaining the softness in the bounce mode. Experimental results of the bus fitted with the roll-enhanced air spring suspension are provided and compared with the original bus. Dynamic responses, such as roll angle, lateral acceleration and bounce acceleration are used to evaluate the handling stability and ride comfort of the bus. Results show that the new design can effectively improve the bus handling while maintaining the ride comfort.