Abstract: The study on transmission energy flows and loss for the wet axle in the heavy vehicle are the base of economy, security, power performance of vehicle. The existing researches focus on gear box energy loss under simple operating model, and the fine comprehensive study of transmission system energy flows and loss based on diver vehicle road under complicated operating model is scarce. The energy flows and loss of transmission system in wet axle under typical cycle operation of heavy vehicle are analyzed, and the mathematical models of different energy loss style are built. The influencing factors of energy flows and loss under vehicle cycle operating are considered, after the assemblies and system energy flows and loss are analyzed based on bond graph theory, the total transmission system energy flows and loss models are built in the end. The nonlinear energy flows and loss in wet axle on driver vehicle road under general operating model can be analyzed on the combination of this dynamic model with vehicle experimental data, even under complicated operating model as drive slipping, brake slipping, steering, wheels load and gravity center changing, etc. which provide the feasible method for energy flows and loss study and accurate calculation under complicated operating model.

Key words: bond graph, energy flows, energy loss, heavy vehicle, system model, transmission system, wet axle