Effect of Lift Axle Suspension Design on Heavy Commercial Vehicle Handling Performance

The cost of fuels used for automobile are rising in India on account of high global crude oil prices. The fuel cost constitutes major portion of total cost of operation for Heavy commercial vehicles. Hence, the trend is to carry the goods transport through higher payload capacity rigid/straight trucks that offer lower transportation cost per unit of goods transported. This is driving the design of multi-axle heavy trucks that have lift axles. In addition, improved network of highways and road infrastructure is leading to increase in average operating speed of heavy commercial vehicles. It has made increased focus on occupant as well as road safety while designing the heavy trucks. Hence, the analysis of lift axle suspension from the point of view of vehicle handling and stability is essential. There are two basic kinds of lift axle designs used in heavy commercial vehicles: self-steered lift axle having single tire on each side and non-steered lift axle with dual tires on each side. The effect of these lift axles on handling performance of heavy trucks is analyzed using multibody dynamics simulations in MSC-ADAMS. The roll stiffness of lift axle simulation models is validated using axle articulation test on vehicle. The change in steady state handling performance parameter with respect to baseline vehicle is compared for two designs of lift axle. Further, the amount of benefit obtained using stabilizer bar is calculated through simulation.