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Multi-Objective Optimization of Fuel Efficiency and Emissions for Ethanol-Fueled Series Hybrid Vehicles Using Metaheuristic NMPC
Last modified: 2026-07-07
Abstract
Series hybrid electric vehicles (HEVs) allow engine operating points to shift into higherefficiency regions by leveraging the hybrid energy system. Usually, standard energy management systemsapproximate energy conversion dynamics using steady-state maps, which leads to a sub-optimal controlpolicy when fuel consumption and pollutant emissions are observed under engine transient demands. Toovercome this issue, this paper proposes a multi-objective optimization strategy to reduce these indices. AGrey Wolf Optimization (GWO) metaheuristic algorithm is used to optimize the Nonlinear Model PredictiveController (NMPC) parameters offline using a MATLAB/Simulink model built from the experimentalmean-value maps of an ethanol-fueled internal combustion engine (ICE) with transient considerations. Finally, the parameterized NMPC is used to experimentally control an ethanol genset across five powertransitions. The adaptive approach reduced the air-fuel ratio error (˜λ = 1) by an average of 8.56% andfuel consumption by 4.3% when compared to conventional PI-based controllers.