Dynamic Full Range Input Shaping of Injection Parameters for Reduction of Transient NOx Emissions

For modern passenger car Diesel engines strong limitations on emissions, due to legislation, require large efforts in combustion and aftertreatment control. This control problem is mainly approached by an intensive stationary calibration process and dynamic compensation techniques. However, large differences in combustion conditions between steady state, as used for calibration, and real transient maneuvers, such as tip-ins, can lead to undesired emission peaks. Against this background, the present work adapts a previously introduced input shaping strategy for injection parameters, such that it is applicable in the full engine operation range. Different to the former approach, the shape of the correction profile is determined directly from identifued local models of the selected injection parameters to the NOx response. By using local linear models it is possible to consider variations in the system dynamics and parameterize the input shapers in an automated fashion. Additionally this approach can be applied together with a state of the art engine control, since it does not need a change in the base calibration. The improved strategy is evaluated on a passenger car Diesel engine and it is shown that a reduction of the undesired NOx overshoot can be achieved without impacting other performance indicators.