Fig. 7 shows the results for the compressor model and the heat transfer model ˙Qc. The measurements represented by
hc,adim˙ c are relieved from the heat transfer. Measurements 1-74 represent the cold measurement, data points
75-176 are measured with injection. Even in the zoomed section with low turbocharger power the model fits the
data well. The averaged root mean squared error of a seven fold cross validation is 39.6W. At operation points with
low compressor load the modelled heat transfer into the compressor housing has a large effect with respect to the
aerodynamic power. Especially for the data points 1 to 15 the contribution of enthalpy by the heat transfer is large.
The heat transfer into the compressor housing ranges from 100W to 300W.
Fig. 7. Model of the compressor power Pc with the corrected aerodynamic temperatures T′1 and T′2 and the
modelled heat transfer into the compressor housing ˙Qc, zoom into data with low power