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 in-cylinder 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, the relation between engine torque and features was identified and in addition also models for the relation between features and injection parameters, like the angle and amount of the main injection, were obtained. These models were then used for the active control of the features. The method was implemented on a 2L common rail Diesel engine at the testbench of the JKU Linz and led to initial results in a torque control application.