Multi-objective optimization investigation of natural gas engine operating parameters using model-based methodologies

摘要

In order to improve the comprehensive performance of a heavy-duty natural gas engine, the paper developed a strategy to efficiently optimize operating parameters. An approximate mathematical model, which the input control variables were air-fuel ratio and ignition advance angle while the output response were a set of eight core indicators of characterizing the whole performance of engine, was established using response surface method and further validated by test results. A multi-objective and multi-variable optimization function was built with a compromise consideration between the power, economy, emission and thermal load of the engine. The optimal operating parameters under all conditions were obtained by the global optimization with multi-island genetic algorithm. The comparison results showed that, with optimal operating parameters, the engine maintained its original power, but with the drop in gas consumption rate (1.11%), maximum combustion temperature (1.46%) and NO_x emission (97.45%).