Calculation of unsteady flow in tubes of combustion engines with special regard to multiple branching

A theoretical basis for numerical analysis of unsteady flow in internal combustion engines is suggested. By a general study of an arbitrary throttle point as control volume, only two flow conditions-inlet flow and outlet flow-have to be computed. The throttle-point function is reduced to linking tube parts in a logical way. The convergence criteria of the solution methods used (Lax-Wendroff, Hartree, Predictor Corrector, and fixed point method) guarantee that the solutions are unequivocal. Limiting value studies lead to the formulation of an algorithm, which allows the computation of the throttle flow by multiple branching.