Study on HCCI-SI Combustion Using Fuels Ethanol Containing

Bio-ethanol is one of the candidates for automotive alternative fuels. For reduction of carbon dioxide emissions, it is important to investigate its optimum combustion procedure. This study has explored effect of ethanol fuels on HCCI-SI hybrid combustion using dual fuel injection (DFI). Steady and transient characteristics of the HCCI-SI hybrid combustion were evaluated using a single cylinder engine and a four-cylinder engine equipped with two port injectors and a direct injector. The experimental results indicated that DFI has the potential for optimizing ignition timing of HCCI combustion and for suppressing knock in SI combustion under fixed compression ratio. The HCCI-SI hybrid combustion using DFI achieved increasing efficiency compared to conventional SI combustion. Feed-forward and feed-back control systems based on DFI enabled the transient operation including acceleration and deceleration during HCCI combustion, re-ignition of HCCI combustion after fuel cut mode, HCCI-SI-HCCI combustion transition, and suppression of knock in SI combustion.