Handling Analysis of a Three-Axle Intercity Bus

This paper describes the methodology adopted at T-Systems do Brasil, for performing handling analysis of commercial vehicles. Its application to an intercity bus with 3 axles is presented. The objective is to improve primary suspension characteristics alone, with respect to both comfort and handling and to study the behavior of the full vehicle with respect to handling and to improve it through the changes of primary suspensions characteristics. The methodology adopted was the development of a complete multibody model of the bus (Figure 4) in ADAMS, considering all the major non-linearities of the actual vehicle, such as air spring and shock absorber curves, suspension bump stops and tire model (Delft). Once having the model, several analyses were carried out including, modal, single lane change, double lane change, steering impulse and sine steering sweep. The results of these analyses were evaluated and modifications to the design were suggested in order to achieve the objectives of this work (to improve the primary suspension characteristics and also the handling behavior of the full vehicle). These modifications were implemented at a physical prototype and measurements have not been carried out yet. However, qualitative impression (not yet quantitative results), indicates an improvement in overall vehicle handling behavior.