Attainment and Load Extension of High-Efficiency Premixed Low-Temperature Combustion with Dieseline in a Compression Ignition Engine

Abstract

A study of high-efficiency premixed low-temperature combustion (LTC) with dieseline (a blend of diesel and gasoline) was conducted on a high-speed compression ignition engine and strategies to broaden the operational range of this dieseline LTC were investigated. Increased ignition delay and higher volatility of dieseline relative to diesel fuel contribute to produce a well-mixed charge, and a simultaneous reduction in NOx and smoke emissions with a moderate exhaust gas recirculation (EGR) rate can be achieved across a relatively narrow load window. An intake boost strategy was employed to broaden the LTC operational window. Higher intake pressure increases air charge and allows for higher fuelling, so the upper load limit of this LTC mode is extended. An increase in NOx emissions is observed at light to mid loads, but a slight increase in EGR rate can reduce NOx emissions to an acceptable level. Because dieseline requires only a relatively light use of EGR, combustion efficiency across the entire dieseline LTC operational range is maintained at a high level.