TY - GEN
T1 - Investigation of injection strategies to improve high efficiency rcci combustion with diesel and gasoline direct injection
AU - Wissink, Martin L.
AU - Lim, Jae H.
AU - Splitter, Derek A.
AU - Hanson, Reed M.
AU - Reitz, Rolf D.
PY - 2012
Y1 - 2012
N2 - Experiments were performed to investigate injection strategies for improving engine-out emissions of RCCI combustion in a heavy-duty diesel engine. Previous studies of RCCI combustion using port-injected low-reactivity fuel (e.g., gasoline or iso-octane) and direct-injected high-reactivity fuel (e.g., diesel or n-heptane) have reported greater than 56% gross indicated thermal efficiency while meeting the EPA 2010 heavy-duty PM and NOX emissions regulations in-cylinder. However, CO and UHC emissions were higher than in diesel combustion. This increase is thought to be caused by crevice flows of trapped low-reactivity fuel and lower cylinder wall temperatures. In the present study, both the low- and high-reactivity fuels were direct-injected, enabling more precise targeting of the low-reactivity fuel as well as independent stratification of equivalence ratio and reactivity. Experiments with direct-injection of both gasoline and diesel were conducted at 9 bar IMEP and compared to results from experiments with port-injected gasoline and direct-injected diesel at matched conditions. The results indicate that reductions in UHC, CO, and PM are possible with direct-injected gasoline, while maintaining similar gross indicated efficiency as well as NOX emissions well below the EPA 2010 heavy-duty limit. Additionally, experimental results were simulated using multi-dimensional modeling in the KIVA-3V code coupled to a Discrete Multi-Component fuel vaporization model. The simulations suggest that further UHC reductions can be made by using wider injector angles which direct the gasoline spray away from the crevices.
AB - Experiments were performed to investigate injection strategies for improving engine-out emissions of RCCI combustion in a heavy-duty diesel engine. Previous studies of RCCI combustion using port-injected low-reactivity fuel (e.g., gasoline or iso-octane) and direct-injected high-reactivity fuel (e.g., diesel or n-heptane) have reported greater than 56% gross indicated thermal efficiency while meeting the EPA 2010 heavy-duty PM and NOX emissions regulations in-cylinder. However, CO and UHC emissions were higher than in diesel combustion. This increase is thought to be caused by crevice flows of trapped low-reactivity fuel and lower cylinder wall temperatures. In the present study, both the low- and high-reactivity fuels were direct-injected, enabling more precise targeting of the low-reactivity fuel as well as independent stratification of equivalence ratio and reactivity. Experiments with direct-injection of both gasoline and diesel were conducted at 9 bar IMEP and compared to results from experiments with port-injected gasoline and direct-injected diesel at matched conditions. The results indicate that reductions in UHC, CO, and PM are possible with direct-injected gasoline, while maintaining similar gross indicated efficiency as well as NOX emissions well below the EPA 2010 heavy-duty limit. Additionally, experimental results were simulated using multi-dimensional modeling in the KIVA-3V code coupled to a Discrete Multi-Component fuel vaporization model. The simulations suggest that further UHC reductions can be made by using wider injector angles which direct the gasoline spray away from the crevices.
UR - http://www.scopus.com/inward/record.url?scp=84892643396&partnerID=8YFLogxK
U2 - 10.1115/ICEF2012-92107
DO - 10.1115/ICEF2012-92107
M3 - Conference contribution
AN - SCOPUS:84892643396
SN - 9780791855096
T3 - ASME 2012 Internal Combustion Engine Division Fall Technical Conference, ICEF 2012
SP - 327
EP - 338
BT - ASME 2012 Internal Combustion Engine Division Fall Technical Conference, ICEF 2012
T2 - ASME 2012 Internal Combustion Engine Division Fall Technical Conference, ICEF 2012
Y2 - 23 September 2012 through 26 September 2012
ER -