Modeling and Simulation of Lift Axle Control Valve

A lift axle suspension system in a heavy commercial vehicle enables raising and lowering of the lift axle depending on the vehicle load condition. The states (raising and lowering) of the axle will be in logical sequence which depends on the vehicle load, ignition state, gear state and traction requirement. To arrive this complicate logic, the Lift Axle Control valve is designed. This LACV is an intricate assembly of pneumatic 3/2 valve, 5/2 valve, relay valve and solenoid valves. To predict the performance of this valve under various vehicle conditions, the entire valve is modeled in one of the commercially available multi-domain physical modeling software employing bond graph technique and lumped system and the performance is predicted. This paper deals with the modeling of LACV, simulation of misbehavior of LACV under certain condition, and the design analysis carried out to arrive design solution.