“…Both the compressor speed and pressure ratio usually fit well the measured values (Westin & Ångström, 2003). Conversely, the power from the turbine often has to be adjusted for each single operating conditions for many reasons (Westin et al, 2004): -The flow entering the turbine in the engine installation is heavily pulsating, whereas the turbine performance maps are usually measured under steady-state conditions; -During each engine cycle, the pulsating flow covers a large operating range, and this means that a large portion of the map is covered for each cycle. Often, the map is not measured with a large enough range, thus the software needs to extrapolate it, and this extrapolation may be a source of error; -In most cases, the maps are not measured for the low-speed range of the turbocharger.…”