Abstract
A generic model of an automotive driveline is developed by the authors. Both two -wheel drive and four-wheel drive architectures are modeled. More variants are analyzed for the complete driveline model, by considering rigid or compliant halfshafts, as well as rigid or tire slip characteristics model for the wheels. The authors emphasize on the right causality assignment between transmission, differential, axle (halfshafts) and wheels components of the drivetrain system, in order to generate correct differential equations, without algebraic loops. Throughout the paper, the bond graph technique is used for proper combination of individual submodels, because of its straightforward ability to identify elements in derivative causality, which inherently generate algebraic loops. Afterwards, a SimulinkTM block-diagram model is created for every combination of driveline submodels. Finally, a general block -diagram model of the two -wheel drive system is derived from these particular models. The latter model can easily be included in complex powertrain simulations, the same block allowing any combination of axle and wheel modeling hypotheses. Numerical simulations of standstill accelerations are performed, considering the same vehicle data in all cases. The general driveline model can catch low frequency dynamics of the drivetrain, typically useful for later integrated powertrain control problems.
Keywords: Driveline, Algebraic Loop, Causality Analysis, Modeling and Simulation, Block Diagrams, Bond Graphs, Shuffle Mode Oscillations