In its original specification, the burn rate model described in Chapter 2.2 only allows for a prediction of moderate fuel variations, like adding hydrogen to methane (see [74]). For a more significant fuel variation like methane, gasoline and ethanol, a recalibration is necessary (see Figures 5.2, 5.3 and 5.4). The reason for the needed recalibration is either the burn rate model itself or a missing, fuel-dependent influence.