A Study on Mode Transition Control between PCI and Conventional Combustion in a Diesel Engine

Abstract

For the development of practical applications of premixed compression ignition (PCI) combustion, it is necessary to ensure its robustness to both environmental conditions and fuel properties. Furthermore, combustion mode transition between PCI and conventional combustion in the dual-mode operation is required as PCI combustion is limited only in light-to-medium load operation. A simple mode transition scheme, however, tends to result in an increase in exhaust emissions. In this study, a new strategy to control mode transition with minimized oxides of nitrogen (NO x) and smoke spikes in transition was developed. In the control system, a real- time calculation of the heat release rate was performed using the in-cylinder pressure diagram for the feedback control of mode transition. The effectiveness of the mode transition control system developed here was evaluated in the JE05 transient test cycle. As a result, it was confirmed that the mode transition control system which controls fuel injection and air management systems using parameters such as a combustion index (MFB50 angle), intake oxygen (O2) concentration, and excess air ratio allowed smooth combustion mode transition without increased exhaust emissions.