Cascaded control of combustion and pollutant emissions in diesel engines

Control of the emissions of diesel engines is an upcoming approach for complying with legislation while limiting the calibration effort. In this paper, a controller for engine-out NOx and PM is combined with a controller for the center of main combustion and the indicated mean effective pressure. The inner cascade combustion controller effectively reduces unwanted influences on the combustion. These influences are partly coupled to the outer-loop manipulated variables and partly result from disturbances which commonly appear in diesel engines. Robust stability is analyzed and holds in a wide operating range. Performance of the control structure is demonstrated with experiments.