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Proposing Institution

Institut für Technische Verbrennung, RWTH Aachen
Project Manager

Tobias Falkenstein
Templergraben 64
52056 Aachen
Internal combustion engines are still the dominant energy conversion system for on-road applications. Even in the mid-term, the main energy carrier used in the transportation sector will be gasoline which is typically burned in spark-ignited (SI) engines. In the past years, efforts on increasing efficiency have mainly utilized turbo/supercharging in combination with direct injection (DI) as means of increasing engine specific power. However, this trend involves a higher probability for the occurrence of certain abnormal combustion phenomena. At low-load conditions, DISI engines are often operated with stratified fuel-air mixture potentially combined with exhaust gas recirculation (EGR). These conditions can be critical for ignition to occur and may result in misfires. At maximum load, increased in-cylinder pressures due to supercharging result in higher probability of pre-ignition events prior to the intended spark ignition. These abnormal combustion events can be very violent and may even lead to engine destruction. Within the proposed project, the existing Large-Eddy Simulation (LES) framework will be extended to efficiently compute combustion in SI engines with high accuracy. Validation against high-quality experimental data sets provided by the Engine Combustion Network will be conducted and results will be contributed to this international collaboration to support the identification of most urgent questions for future engine research. Multi-cycle simulations at critical operating conditions will be performed at low- and full-load. The effects of local and cyclic scalar fluctuations on misfires will be in focus of the analysis at low-load conditions. At high load, a new theory for prediction of mega-knock events proposed by Peters will be tested and extended to develop a reliable method for evaluation of local detonation probability. In addition to giving a better understanding of complex physical phenomena, the proposed high-resolution LES project is meant to be a preliminary study for a subsequent direct numerical simulation (DNS) of a reactive engine configuration.

Impressum, Conny Wendler