Cylinder-Pressure Based Injector Calibration for Diesel Engines

One way of complying with future emission restrictions for diesel engines is to use pressure sensors for improved combustion control. Implementation of pressure sensors into production engines would lead to new possibilities for fuel injection monitoring where one potential use is injector calibration. The scope of this thesis is to investigate the possibility of using pressure sensors for finding the minimal energizing time necessary for fuel injection. This min-imal energizing time varies over the injector’s lifetime and therefore requires a re-calibration. The necessary energizing time can be found by estimating the injected fuel mass at different rail-pressures during a calibration state op-erating under specific engine conditions. Two different approaches based on in-cylinder pressure were used for fuel mass estimation. The result is based on a comparison to a non pressure based production line calibration function. Both fuel mass estimations show a correlation with convincingly accuracy for calibration use but with the possibility of further improvements. One approac