This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Fuel Reactivity Controlled Compression Ignition (RCCI) Combustion in Light- and Heavy-Duty Engines
ISSN: 1946-3936, e-ISSN: 1946-3944
Published April 12, 2011 by SAE International in United States
Citation: Kokjohn, S., Hanson, R., Splitter, D., Kaddatz, J. et al., "Fuel Reactivity Controlled Compression Ignition (RCCI) Combustion in Light- and Heavy-Duty Engines," SAE Int. J. Engines 4(1):360-374, 2011, https://doi.org/10.4271/2011-01-0357.
Single-cylinder engine experiments were used to investigate a fuel reactivity controlled compression ignition (RCCI) concept in both light- and heavy-duty engines and comparisons were made between the two engine classes. It was found that with only small changes in the injection parameters, the combustion characteristics of the heavy-duty engine could be adequately reproduced in the light-duty engine. Comparisons of the emissions and performance showed that both engines can simultaneously achieve NOx below 0.05 g/kW-hr, soot below 0.01 g/kW-hr, ringing intensity below 4 MW/m2, and gross indicated efficiencies above 50 per cent. However, it was found that the peak gross indicated efficiency of the baseline light-duty engine was approximately 7 per cent lower than the heavy-duty engine. The energy balances of the two engines were compared and it was found that the largest factor contributing to the lower efficiency of the light-duty engine was increased heat transfer losses. Detailed CFD modeling was used to explore options to reduce the heat transfer losses of the light-duty engine. It was found that by reducing the swirl ratio from 2.2 to 0.7, increasing the engine speed from 1900 to 2239 rev/min, and improving the combustion chamber geometry, the heat transfer losses in the light-duty engine could be reduced by the equivalent of 2 per cent of the fuel energy. The modeling showed that light duty engine could achieve 53 per cent gross indicated efficiency, while maintaining near-zero NOx and soot, and an acceptable ringing intensity.