A Central Differential Gear Ratio Optimization of a 6x6 Articulated Dump Truck

This paper starts with an analysis of design configurations of the drivelines with different power-dividing units (PDUs) of main dump truck manufacturing companies. As it follows from the analysis, improvements of articulated truck energy efficiency and reduction of fuel consumption by optimizing the power distribution to the drive wheels are still open issues. The problem is that a variety of operating and terrain conditions of dump trucks requires different wheel power distributions that cannot be provided by one set of PDUs employed in a truck. The central PDU in the transfer case was identified as the most important PDU among the five PDUs, which plays a crucial role in the power distribution between the front axle and the rear tandem of a 6x6 articulated dump truck. The paper formulates a constraint optimization problem to minimize the tire slippage power losses by optimizing the power distribution between the drive wheels. A 3D-multi-body mathematical model of a dump truck with the 29/68 ton of the curb/fully loaded mass ratio is described to solve the optimization problem. The terrains are modelled with stochastic topographical profiles, stochastic rolling resistance and tire tractionslippage characteristics. Computational sets of optimal distributions of wheel circumferential forces/torques that correspond to the optimal wheel power splits are presented for different operating and terrain conditions with the purpose to determine optimal values of the central differential gear ratio. The paper discusses the range of changes of the optimal gear ratio in different conditions.