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Title: FUEL EFFECTS ON COMBUSTION WITH EGR DILUTION IN SPARK IGNITED ENGINES

The use of EGR as a diluent allows operation with an overall stoichiometric charge composition, and the addition of cooled EGR results in well-understood thermodynamic benefits for improved fuel consumption. This study investigates the effect of fuel on the combustion and emission response of EGR dilution in spark ignited engines. A 2.0 L GM Ecotec LNF engine equipped with the production side-mounted direct injection (DI) fueling system is used in this study. Ethanol, isooctane and certified gasoline are investigated with EGR from 0% to the EGR dilution tolerance. Constant BMEP at 2000 rpm was operated with varying CA50 from 8 CAD to 16 CAD aTDCf. The results show that ethanol gives the largest EGR tolerance at a given combustion phasing, engine load and speed. The improved EGR dilution tolerance with ethanol is attributed to a faster flame speed, which manifests itself as shorter combustion duration. Data shows that the combustion stability limit occurs at a critical combustion duration that is fuel independent. Due to different flame speeds, this critical combustion duration occurs at different EGR levels for the different fuels.
Authors:
 [1]
  1. ORNL
Publication Date:
OSTI Identifier:
1324105
DOE Contract Number:
AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Conference: Central States Meeting of the Combustion Institute, Knoxville, TN, USA, 20160515, 20160517
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Fuels, Engines and Emissions Research Center; National Transportation Research Center (NTRC)
Sponsoring Org:
EE USDOE - Office of Energy Efficiency and Renewable Energy (EE)
Country of Publication:
United States
Language:
English
Subject:
EGR; stability; COV; flame speed