Flexible Clean Propulsion Technologies

Variable Valve Actuation enabled Reactivity-Controlled Compression Ignition in a Natural-Gas/Diesel Marine Engine

Author

Kim Jeyoung , Kakoee Alireza , Hyvönen Jari , Mikulski Maciej

Category

Publication channel

Keywords

Emissions Reduction, Combustion Phasing, Predictive Simulation, marine engines, FlexCPT

Year of the publication

2024

Citation

J. Kim, A. Kakoee, J. Hyvonen, and M. Mikulski, “Variable Valve Actuation Enabled Reactivity-Controlled Compression Ignition in a Natural-Gas/Diesel Marine Engine”, presented at the THIESEL 2024 Conference on Thermo- and Fluid Dynamics of Clean Propulsion Powerplants, 10–13 September 2024, Valencia, Spain. https://cleanpropulsion.org/wp-content/uploads/2025/06/THIESEL-2024-1.pdf

Language

English

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The present study numerically investigated two variable valve actuation (VVA) strategies – early intake valve closing (EIVC) and second exhaust valve re-opening (2EVO) with a large bore marine engine operating under natural-gas/diesel RCCI mode. A fully calibrated and validated 1D engine model was utilized for VVA simulation via commercial software, GT-Power. In order to capture RCCI combus-tion behaviour on VVA, a physic-based chemical kinetic multizone model (UVATZ) was directly coupled with GT-Power. The simulation results revealed that EIVC and 2EVO could control combustion phase and extend load range to some extent by controlling in-cylinder thermal condition right before the com-bustion initiates. EIVC retards combustion phase by decreasing compression temperature while 2EVO advances combustion onset by increasing in-cylinder temperature by trapping hot residual gases.