Achieving ride comfort in bus suspension by varying air spring performance

Air springs are widely used in commercial buses to obtain better quality of ride and comfort. Selecting the right air spring is a critical aspect of suspension design. However, this selection process is often constrained by the limited availability of off-the-shelf components as the development of a custom air spring involves long lead time and high tooling cost. This can be justifiable only at high production volumes. Air springs are tunable as compared to conventional mechanical metal springs. Their performance can be adjusted by varying the internal air pressure and volume, enabling them to accommodate a wide range of vehicle load conditions. In actual design practice, component packaging constraints and fixed mounting dimensions often restrict the choice of air spring. Additionally, Front and rear suspension requires air springs with different characteristics. To overcome these limitations, an auxiliary air tank is also called a ping tank that can be used along with an existing system. This allows for effective tuning of the spring characteristics without new development of air spring. This paper focuses on a comprehensive study involving analytical calculation, physical testing and mathematical modeling in MATLAB to explore the influence of varying air volume on air spring performance. This mathematical model is developed in MATLAB to analyze the impact of air volume changes on the dynamic stiffness of the air spring. The outcomes of the model are validated through physical testing data.