Simulation of ECU for flexible fuel injection system in SI engine

A hybrid renewable energy system utilizes an SI engine fueled by a syngas–biogas–hydrogen mixture with a wide range of compositional variations. Due to the significantly different stoichiometric air/fuel (A/F) ratios of these fuels, conventional fuel supply systems cannot meet the engine's operational requirements. Simulation results indicate that a 4 mm injector is suitable for biogas/hydrogen but not for syngas, whereas a 9 mm injector is appropriate for syngas but unsuitable for the other fuels. To handle the large variations in composition, a twinning injector system, consisting of two injectors, has been proposed. When the syngas content is low, only one injector operates; as the syngas proportion increases, the second injector is activated. This paper presents the simulation results of the ECU-controlled twinning injector system, along with experimental validation on a Honda GX390 engine.