Torque Control of a Diesel Engine by an Eigenpressure Based Approach

Although the application of cylinder pressure sensors to obtain insight into the combustion process is not a novel topic itself, the recent availability of inexpensive incylinder pressure sensors has prompt an upcoming interest for the utilization of the cylinder pressure signal within engine control and monitoring. By the use of techniques, like principle component analysis, it is possible to reduce the high amount of data in the pressure signal during one cycle whilst preserving as much as possible of the fundamental information. Up to now this extracted information, the so called features, were mainly used for modeling tasks and virtual sensors. In this work a converse approach is proposed, namely to directly control these features to desired values by controlling the injection parameters. To this end, first the relation between features and the engine torque is identified and used to design a desired set of features. In addition also models for the relation between features and injection parameters, like the angle and amount of the main injection, were obtained and used for the active control of the features. The method was implemented on a 2L common rail Diesel engine testbench and led to promising results in a torque control application.