Emission regulations and fuel economy regulations are becoming more severe simultaneously, and they give much issue for automotive diesel R&D society. Moreover, emission test cycles are getting more tough transient conditions, like as WLTP. To meet the emission regulations in this trend, in-cylinder combustion requires more precise control. Designing hardware robustly and improving controllable are possible solutions to accomplish the precise combustion control. On the other hand, combustion control based on in-cylinder pressure signal is helpful to control in-cylinder combustion directly. Combustion control using in-cylinder pressure signal is also known to be useful to reducing engine-by-engine exhaust emissions variation due to the manufacturing tolerance, variation of fuel specification and deterioration of engine component during the whole lifetime. In this paper, the main components of combustion control algorithm are presented, especially focused on the control algorithm coordinator which governs entire control algorithm.
Combustion control algorithm based on the in-cylinder pressure is composed of combustion analyzer, combustion control algorithm and control algorithm coordinator. Combustion analysis algorithm analyzes in-cylinder pressure signal, and it calculates MFB50, IMEP and in-cylinder peak pressure in real-time. Combustion control algorithm controls the main injection timing and duration to control the MFB50, IMEP and maximum in-cylinder pressure. Control algorithm coordinator governs entire control algorithm, it monitors the operating condition of vehicle and external conditions. Control algorithm give orders to the every component in entire algorithm whether operate or not. The control algorithm is demonstrated at engine test bench test and vehicle test.