Experimental Analysis of Unsteady Phenomena Upstream of a Turbocharged Engine

According to a methodology that has been proposed by the authors in previous papers, measurements of instantaneous mass flow rate supplying a turbocharged engine were carried out by means of time-varying pressure data recording and of a numerical flow model: this methodology allows unsteady phenomena upstream of the inlet manifold to be followed, so that it seems particularly suitable also to the analysis of engine transient behaviour.

The paper presents improvements in the method, since, until now, it has been tested only in the case of a naturally aspirated engine; hence, particular problems arising in unsteady flow analysis of turbocharged engines had to be overcome, owing to the disturbance induced by compressor motion and intake valves closing on the pressure signals.

Particular attention is paid to the analysis of unsteady behaviour of the supercharging compressor that may be performed by employing the experimental-theoretical inlet flow model.