Project: DNS4ICE - DNS for modelling highly diluted and multi-fuel combustion in internal combustion engines

Prace Call: 17th
ID: 2018184407, Leader: Karine Truffin
Affiliation: IFP Energies nouvelles, FR
Research Field: Engineering
Collaborators: Edouard Suillaud IFP Energies nouvelles FR , Maxime Tarot IFP Energies nouvelles FR , Olivier Colin IFP Energies nouvelles FR , Stephane Jay IFP Energies nouvelles FR , Karine Truffin IFP Energies nouvelles FR
Resource Awarded: 16.8 Mil. core hours on JUWELS

Abstract

Future hybrid vehicles will essentially be powered by spark-ignition engines (SIE), whatever the hybridisation level. Designing and calibrating SIE to achieve optimal performance in the context of hybridization and real driving conditions usage represents a major scientific and technological challenge. These technological solutions could not be targeted without mastering flow, mixing and combustion down to the individual engine cycle, for which novel simulation approaches such as Large-Eddy Simulation offer the possibility to study the behavior of instantaneous engine cycles. This is of critical importance for improving the engine performance and emissions in highly non-stationary situations such as fast transients, cold start, extreme operating conditions or the restarts of powertrains when coupling electrical/thermal engines. One technology favoured today by engine manufacturers for SIE is downsizing, which consists in reducing the displacement and increasing the specific power by using a turbocharger. This technology is however limited in practice due to an increased occurrence of abnormal combustions which lead to using sub-optimal spark timings. A key measure for limiting the occurrence of abnormal combustion is to increase the EGR (Exhaust Gas Recirculation) rate up to 30% but this leads to larger cycle to cycle variability and decreased heat release rates. In order to reach such high EGR rates, complex strategies have to be developed (aerodynamics, spark ignition, injection targeting and timing, chamber geometry etc…) the design and optimization of which increasingly rely on Computational Fluid Dynamics (CFD). Dual Fuel Combustion (DFC) is seen as another promising concept to combine advantages of spark-ignited and compression ignited engines. Its principle is to inject a high cetane number fuel to initiate combustion of the premixed charge (gas/air or gasoline/air) initially admitted. The objective of DNS4ICE is to improve the understanding of the phenomena during DFC and highly diluted combustion and provide appropriate combustion models. The usage of dedicated Direct Numerical Simulations (DNS) on academic configurations under the extreme conditions found in future engines will provide detailed local flame statistics for orienting and supporting the combustion model developments.