Abstract
In order to maximize the efficiency of light-duty gasoline engines, the Co-Optimization of Fuels and Engines (Co-Optima) initiative from the U.S. Department of Energy is investigating multi-mode combustion strategies. Multi-mode combustion can be describe as using conventional spark-ignited combustion at high loads, and at the part-load operating conditions, various advanced compression ignition (ACI) strategies are being investigated to increase efficiency. Of particular interest to the Co-Optima initiative is the extent to which optimal fuel properties and compositions can enable higher efficiency ACI combustion over larger portions of the operating map. Extending the speed-load range of these ACI modes can enable greater part-load efficiency improvements for multi-mode combustion strategies. In this manuscript, we investigate fuel effects for six different fuels, including four with a research octane number (RON) of 98 and differing fuel chemistries, iso-octane, and a market representative E10 fuel, on the load limits for two different ACI strategies: spark-assisted compression ignition (SACI) and partial fuel stratification-gasoline compression ignition (PFS-GCI) operation. Experimental results show that limits to intake boosting limit high load operation for most fuels, but high smoke emissions for high particulate matter index (PMI) fuels under SACI conditions could also be a limitation. Contrastingly, low load is limited by combustion efficiency, but these effects have more pronounced variation with fuel chemistry for PFS-GCI than with SACI. Additional, distinct effects affecting autoignition timing and peak heat release at higher speeds were identified for fuels having different low temperature heat release (LTHR) propensities for both ACI modes.
Original language | English |
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Journal | SAE Technical Papers |
Issue number | 2021 |
DOIs | |
State | Published - Sep 21 2021 |
Event | SAE 2021 Powertrains, Fuels and Lubricants Digital Summit, FFL 2021 - Virtual, Online, United States Duration: Sep 28 2021 → Sep 30 2021 |
Funding
This research was funded by the U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE) as part Acknowledgments This research was conducted as part of the Co-Optima Initiative sponsored by the U.S. DOE EERE, Bioenergy Technologies and Vehicle Technologies Offices. Co-Optima is a collaborative Initiative of multiple National Laboratories initiated to simultaneously accelerate the introduction of affordable, scalable, and sustainable biofuels and high-efficiency, low-emission vehicle engines. A special thanks to Kevin Stork, Gurpreet Singh, and Mike Weismiller.