Abstract
Engine performance is strongly dependent on gas dynamic phenomena in intake and exhaust systems. Careful design of the manifolds enables the engineer to manipulate the engine torque characteristic. The paper discusses the basic mechanisms of manifold tuning in a high-speed single-cylinder engine via the use of an engine simulation program. In high-performance multi-cylinder engines particular attention must be paid to modelling the flow in pipe junctions. The paper describes a new model which models the pressure losses in multi-pipe junctions. Measured and predicted results are shown for a high-speed four-cylinder engine.