LAUSR

A spark ignition (SI) engine with an ethanol direct injection (EDI) and gasoline port injection (GPI) system has been studied quite recently. In order to investigate its application, experiments were carried out on a single-cylinder 250 cm3 short stroke motorcycle SI engine, which is supplied with the ethanol–gasoline dual injection system. Experimental findings have revealed that EDI helped increase the lean combustion limit owing to the combination effects of the dual injection and ethanol fuel. At the identical engine speed and load, the lean burn limit in the dual injection model was, on average, 0.2 times higher than that in the corresponding single GPI model. Increasing ethanol energy ratio (EER) gave rise to the increase in the lean burn limit; nevertheless, the increase rate began reducing when the EER was above 48% and 42% at 4000 and 3500 rpm, correspondingly. Subsequently, late ethanol direct injection (LEDI), following the intake valve closing slightly extended the lean burn limit, probably, o...