A linear acoustic model for multi-cylinder IC engine intake manifolds including the effects of the intake throttle

This paper presents a linear acoustic model of a multi-cylinder intake manifold that can be used as part of a hybrid time/frequency domain method to calculate the intake wave dynamics of practical naturally aspirated engines. thod allows the user to construct a model of almost any manifold of complex geometry. The model is constructed as an assemblage of sub-models: (i) l for a straight pipe with both ends open and through-flow. l for an expansion chamber consisting of three lengths of pipe laid end-to-end: a narrow bore pipe expanding into a wide bore pipe contracting into a narrower bore pipe once more. l of a side-branch, which includes a model for a straight pipe with one end closed and a model for the three way junction that joins the side-branch to a length of flow pipe. l for an expansion with two (or more) side-branches, which combines the sub-models (i)–(iii) into a multi-way (n-way) junction model. l for an intake throttle. agreement with measurement has been found for each sub-model when bench-tested in isolation and encouraging agreement has been found when many sub-models are used together to model a complex intake manifold on a running engine.