A bumper system for an automobile vehicle includes, in an exemplary embodiment, a beam configured to attach to the vehicle, and an energy absorber coupled to the beam. After ion doping is completed, supply of a material gas is stopped and hydrogen or a rare gas is kept to be supplied. The homogeneity of the overall field distribution is evaluated using an evaluation algorithm and a change of one or more excitation parameters of one or more resonator segments or segment groups to compensate for a known field inhomogeneity is determined. When engine operating conditions call for greater injection control pressure while the retarder is activated, the strategy provides for greater injection control pressure using a pressure versus speed map.