LAUSR

Engine behaviour can be simply defined using mean value engine models (MVEMs) as an average over one engine cycle but there are concerns about the validity of MVEM models during transient operation. In this study, the performance of MVEM is evaluated by comparing air-path dynamics during transient and steady-state operation for a turbocharged gasoline engine. The comparison is performed experimentally by the measurement of port and manifold fast pressures and calculated air mass flow during speed and torque transient tests. In addition, engine models can be linearised to facilitate rapid estimation. In this regard, a nonlinear intake manifold model is linearised and several linear parameter varying (LPV) models are formulated. Investigation of MVEM shows the transient cycles are within the steady-state range, whilst the effects of turbocharger performance are significant. The LPV modelling approach showed approximately 90% conformity between the linear and nonlinear models for estimating manifold pressure.