Efficiency Optimal, Maximum Pressure Control in Compression Ignition Engines

Ever since the invention of the internal combustion engine, there has been an interest in optimizing the in-cylinder pressure to achieve reliable and efficient work output. With the use of in-cylinder pressure sensors, piezoelectric injector actuation, the possibility of multiple injection events and the increased availability of computation power, cycle-to-cycle, in-cylinder pressure optimization has become a realizable technology. The objective of this work was to investigate how to enable efficiency optimal pressure curves with a maximum cylinder-pressure constraint using multiple fuel injections and in-cylinder pressure-sensor feedback. The objective was achieved by the use of a heuristic controller design that was found through off-line simulation, using a single-zone in-cylinder pressure model and a parametric combustion-rate expression. The controller was evaluated both in simulation and experimentally on a heavy-duty engine in transient operation.