Full-Time Gasoline Direct-Injection Compression Ignition (GDCI) for High Efficiency and Low NOx and PM

Investigation on Multiple Injection Strategies for Gasoline PPC Operation in a Newly Designed 2-Stroke HSDI Compression Ignition Engine

“…However, they are still considered as promising, since they are kept within the range of values reported in the literature on light-duty 4-stroke engines running with the PPC concept at low load conditions with lower octane gasoline fuels [29]. Furthermore, Sellnau et al reported important benefits in efficiency and emissions levels using dedicated engine hardware (piston and injector nozzle) welloptimized for PPC operation compared to using conventional hardware optimized for CDC [39,40]. As a final remark, previous research performed at 10.4 bar IMEP showed how retarding the timing of the late injection (SoE3) can also be used to control noise by softening and slowing combustion rate once the combustion starts, but with a moderate effect compared to SoE2 [44].…”

“…Moreover, Sellnau et al confirmed the potential of a triple injection strategy for increasing thermal efficiency compared to single injection strategies thanks to reduced heat losses during the expansion stroke given by a more favorable fuel distribution during combustion which results in less contact between hot combustion gases and chamber walls [38,39].…”

“…For instance, gasoline fuels with high octane number (ON) provide a challenge to ensure reliable ignition especially in the low load limit, while fuel blends with lower ON present problems for extending the ignition delay in the high load range and avoid the onset of knocking combustion. This supposes that the PPC concept requires different fuel reactivity and/or advanced valvetrain and boost/EGR systems to assure proper ignition control, and optimize emissions and efficiency in the full engine map [39]. Thus, there are still many practical issues which remain under investigation before reaching a production-viable powertrain; such as the injection system requirements, combustion chamber design, air charging strategy definition, among others.…”

“…Since this early work, many research groups from Lund University [27][28][29][30][31][32], University of Cambridge [33], Argonne National Laboratory [34][35][36], University of Wisconsin Madison [37] and Delphi Corporation [38][39][40] have performed additional experimental and numerical investigations operating with PPC using different fuels in the octane range of gasoline and ethanol. Different injection strategies have been explored, with various EGR rates, boost pressures, intake temperatures and swirl ratios at different engine loads and speeds.…”

Low-Temperature Combustion of High Octane Fuels in a Gasoline Compression Ignition Engine

“…Soot is known to form mostly at fuel-rich condition, with equivalence ratio ~ 4 or higher (Glassman, 1989), while the formation of NOx is promoted at high combustion temperature ~2,700 K (Akihama et al, 2001, Fujimoto et al, 2002. Increasingly stringent emission standards for low emission of soot and NOX demand newly advanced engine combustion (AEC) concepts such as homogeneous charge compression ignition (HCCI) (Onishi et al, 1979;Najt and Foster, 1983;Epping et al, 2002;Dec et al, 2011), partially premixed combustion (PPC) (Noehre et al, 2006), gasoline compression ignition (GCI) (Kalghatgi et al, 2006;Manente et al, 2009;Kalghatgi et al, 2010;Sellnau et al, 2012;Ciatti et al, 2013), and reactivity controlled compression ignition (Kokjohn et al, 2011). Simply speaking, these AEC concepts have a similar goal of utilizing the fuel stratification and the reactivity of the charge (fuel and air) through various approaches such as injection strategy, dilution, or fuel reactivity that can accomplish desirable combustion and emission performance.…”