Effects of ethanol on combustion and emissions of a gasoline engine operating with different combustion modes

The introduction of fuel economy and CO2 emission legislations for passenger cars in many countries and regions has spurred the research and development of more efficient gasoline engines. The pumping loss at part-load operations is a major factor for the higher fuel consumption of spark-ignition gasoline engines than the diesel engines. Various approaches have been identified to reduce the pumping loss at part-load operations, leading to improved fuel economy, including early intake-valve closing, positive valve overlap and controlled auto-ignition combustion. On the other hand, in order to reduce the CO2 emissions from the fossil fuel, ethanol produced from renewable resources is becoming widely used in the gasoline engine. In this article, the performance, combustion and emissions were measured, analysed and compared between gasoline and its mixture with ethanol (E15 and E85) at a typical part-load condition when a direct-injection gasoline engine was operated with the controlled auto-ignition combusti...