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.