The Effect of Various Parameters on the Crankshaft Torsional Deformation of a Turbocharged Diesel Engine Operating under Transient Load Conditions

ABSTRACT: The modeling of transient diesel engine operation appeared in the early seventies and continues to be in the focal point of research, due to the importance of transient response in the everyday operating conditions of engines. The majority of the simulations have focused so far on thermodynamics, as this directly affects performance and pollutants emissions. As far as dynamic modeling is concerned, simplified approaches are usually adopted in order to save execution time of the simulation code. In this paper, one of the basic simplifications of transient dynamic modeling, i.e. the assumption of the crankshaft being sufficiently rigid is being investigated. In real engine operation, different, instantaneous torsional angles for the engine and load are experienced that lead to angular deformation of the crankshaft. This deformation can assume significant values, particularly during transients, and as such it is of great importance for safe engine operation. The crankshaft angular momentum equilibrium is analyzed in detail taking into account gas, inertia, friction, load as well as stiffness and damping torque contributions. An experimentally validated simulation code is used to study the effect of various parameters on the crankshaft torsional deformation durin