Modelling Engines with Pulse Converted Exhaust Manifolds Using One-Dimensional Techniques

One-dimensional ‘wave-action’ codes are widely used by internal combustion engine manufacturers. However, the modelling of multi-pipe junctions within such simulations presents a problem, since the geometry of the junctions cannot be represented fully using a one-dimensional approach, and it can produce a strongly directional effect on the propagated waves. ‘Pressure-loss’ models of junctions have been devised as boundary conditions for one-dimensional simulations, these allow the some geometry induced effects to be introduced into the calculation. This paper examines the performance of such models, when used to simulate a pulse converter-type junction, under unsteady flow conditions.