A team from Université d’Orléans (France) and IFP Energies nouvelles reports that exhaust gas recirculation (EGR) stratification may be used as a control parameter for combustion speed and therefore may contribute to the extension of the homogeneous charge compression ignition operating range. A paper on their work is published in the International Journal of Engine Research.
The team used a single-cylinder diesel engine to investigate the potential of exhaust gas recirculation dilution stratification as a control technique for homogeneous charge compression ignition combustion with early direct injections.
The results indicate that depending on the intake configuration, the exhaust gas recirculation stratification can be maintained until late timings corresponding to the combustion event, leading to decreased maxima of heat-release rates, as well as decreased combustion noise levels.
...However, although exhaust gas recirculation stratification appears to be an interesting new control technique for homogeneous charge compression ignition combustion, its effect on the combustion was shown to be very sensitive to parameters such as the intake system configuration or the exhaust gas recirculation composition, showing that industrial use of this control technique requires further understanding of the physical phenomena involved.—André et al.
Mathieu André, Bruno Walter, Gilles Bruneaux, Fabrice Foucher, and Christine Mounaïm-Rousselle (2012) Exhaust gas recirculation stratification to control diesel homogeneous charge compression ignition combustion International Journal of Engine Research doi: 10.1177/1468087412438338