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Cycle-by-Cycle Analysis, Knock Modeling and Spark-Advance Setting of a “Downsized” Spark-Ignition Turbocharged Engine
ISSN: 1946-3936, e-ISSN: 1946-3944
Published September 13, 2009 by Consiglio Nazionale delle Ricerche in Italy
Citation: Bozza, F., Siano, D., and Torella, E., "Cycle-by-Cycle Analysis, Knock Modeling and Spark-Advance Setting of a “Downsized” Spark-Ignition Turbocharged Engine," SAE Int. J. Engines 2(2):381-389, 2010, https://doi.org/10.4271/2009-24-0020.
Recently, a tendency is consolidating to produce low displacement turbocharged spark-ignition engines. This design philosophy, known as “engine downsizing”, allows to reduce mechanical and pumping losses at low load as a consequence of the higher operating Brake Mean Effective Pressure (BMEP). The presence of the turbocharger allows to restore the maximum power output of the larger displacement engine. Additional advantages are a higher low-speed torque and hence a better drivability and fun-to-drive. Of course, at high loads, the spark-advance must be carefully controlled to avoid the knock occurrence and this determines a substantial penalization of the fuel consumption. The knowledge of the knock-limited spark timing is hence a key point in order to reduce the fuel consumption drop at high loads.