Experimental study of warm-up and startability operations in a spark ignition engine fueled with ethanol gasoline blends

Thermal transients during warm-up phase influence fuel consumption and combustion stability. Moreover, during engine warm-up, tailpipe emissions are the highest since the catalytic converter has not reached the light-off temperature yet. Therefore, reducing warm-up time would be beneficial for both performance and emissions. In this work, an experimental investigation is carried out on a naturally aspirated four-cylinder spark ignition engine with a displacement of 1.2 liter, equipped with a port fuel injection system. The study compares conventional gasoline with an E30 (i.e. 30% ethanol in gasoline). Tests are performed starting from cold engine conditions and stopped when a fully warmed state is reached. The experimental campaign is conducted at a fixed operating condition of 2000 rpm and 20 Nm load, representative of typical warm-up operation. The analysis focuses on the warm-up duration, defined as the time required to reach steady thermal conditions, and on engine performance parameters, including brake thermal efficiency, brake specific fuel consumption and combustion stability. The aim of this study is to provide experimental insight into the influence of ethanol blending on the warm-up behavior of spark ignition engines under cold-start conditions.