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In the paper the results of an experimental campaign regarding the steady characterization of a turbocharger waste-gated turbine (IHI-RHF3) for gasoline engine application are presented. The turbine behavior is analyzed in a specialized test rig operating at the University of Genoa, under different openings of the waste-gate valve. The test facility allows to measure inlet and outlet static pressures, mass flow rate and turbocharger rotational speed. The above data constitute the basis for the tuning and validation of a numerical procedure, recently developed at the University of Naples, following a 1D approach (1D turbine model - 1DTM). The model geometrically schematizes the entire turbine based on few linear and angular dimensions directly measured on the hardware. The 1D steady flow equations are then solved within the stationary and rotating channels constituting the device. All the main flow losses are properly taken into account in the model.

It is commonly recognized that the paths for improving fuel consumption (BSFC) in a spark-ignition engine at part-load require more advanced valve actuation strategies, which largely affect the pumping work. Since several years, many different solutions have been proposed, characterized by different levels of complexity, effectiveness, and cost. Valve systems currently available on the market allow for variable phasing (VVT - Variable Valve Timing), and/or lift (VVA - Variable Valve Actuation). Usually VVT devices are applied on intake and exhaust camshafts, in the “phased” or “unphased” configuration, as well. VVA devices are instead commonly mounted on the intake camshaft. More recent VVA systems also allow for a double intake valve lift during a single engine cycle (multi-lift), or may include a small intake pre-lift during the exhaust stroke. The latter solutions may determine further BSFC reductions. Alternatively, an external-EGR circuit can be considered, as well.