Model-based engineering-simulation based design of the suspension of city bus

Process of designing of vehicle suspension as a combination of springs and dampers is a very complicated task. In general it requires designing system respecting good ride comfort and good handling at the same time. It is obvious that these two aspects are dependent also of the type of the road on which vehicle is riding. Especially it is important in city buses which are workplaces for bus drivers and each day are transporting thousands of people. Bus suspension system is quite different from car suspension. Because of the mass and size instead of traditional springs, pneumatics springs are used. In some cases, values of damping and stiffness of the spring are adjusted to the proper road in a real bus while driving. It is necessary nowadays to have a virtual assessment that can simulate "bus suspension behaviour" to abstracted suspension parameters such as springs and dampers characteristics. In this paper a multibody model of city bus suspension has been presented. Multibody models are the best way of simulation of dynamic behaviour of the vehicle. Simulations showing how different types of the road affect the structure of the vehicle have been performed. Such prepared model can be then use as an input for optimization of the bus suspension in terms of ride comfort, handling, or even passengers' safety.