Study on the Influence of Air Suspension Levelling Valve Charging and Discharging Characteristics on Heavy Truck Roll Stability

Roll stability is an important attribute which must be accounted for in heavy trucks. In order to analyze the anti-roll performance of the suspension in the early period of development, engineers will generally use Multi Body Dynamics (MBD) simulation software which can save time in the product development cycle. However, air suspension employs levelling valves to adjust the height by charging and discharging air springs. The air spring is typically modeled as a closed container in the simulation; the stiffness change of the air spring caused by the levelling valve is not considered. In this paper, an air suspension with levelling valves model integrated into the multi-body dynamic model of a 6�4 heavy truck is built with a co-simulation technique to investigate the influence of three types of levelling valves arrangement on the roll performance of the suspension under two typical conditions. Type 1 air suspension is equipped with two levelling valves which are respectively arranged on the middle axle and rear axle. Type 2 air suspension is equipped with two levelling valves which are respectively arranged on the left and right sides of the middle axle. Type 3 air suspension is equipped with three levelling valves which are respectively arranged on the middle axle and the left and right sides of the rear axle. Additionally, the influence of the levelling valves' orifice size on the anti-roll performance of the suspension is analyzed. The results show that Type 2 provides better anti-roll performance, and increasing the size of the orifice is beneficial for the levelling valve to act more quickly.