Control and Process Supervision of a Particle Filter System for Diesel Engines

Abstract In particle filter systems for diesel engines in urban traffic, the regeneration of the filter by burning off the soot is a problem. Changes in the engine operating mode during the regeneration make a controlled combustion of the soot in the filter difficult. This paper presents a control concept with process supervision for a filter system with burner assisted full-flow regeneration during engine operation. The goal of the control is to keep the mixed gas temperature in front of the filter at the desired value by manipulating the amount of fuel injected into the burner. The process supervision must ensure that the flame in the burner does not go out, as otherwise unburned fuel will combust in the filler and/or emit as blue smoke; this has to be avoided. The controller and the process supervision are designed based on linear and nonlinear system identification. Measurements of the controller performance made on a test engine show a good behaviour of the closed loop, even during large and rapid variations of engine load.