This study investigates the effects of neat n-butanol replacing conventional diesel fuels to enable clean combustion on a modern common-rail diesel engine. Systematic engine experiments are conducted to examine the combustion characteristics and exhaust emissions in correlation to n-butanol's relatively high oxygen content and high volatility but low ignitability, and control strategies are thereafter developed for enabling clean and efficient combustion of neat n-butanol. Compared to its diesel counterpart, the single-shot injection of neat n-butanol offers substantially reduced NOx emissions without the use of EGR and near-zero soot emissions, but the applicable injection timing window is narrower for n-butanol limited by high maximum rates of pressure rise and/or unstable combustion. EGR is effective to reduce the combustion roughness, but it further narrows the applicable injection timing window and deteriorates the HC and CO emissions. A control strategy that deploys multi-shot injections combined with moderate use of EGR is developed and applied to improve the combustion controllability and exhaust emissions while minimizing the penalties in the engine efficiency. (C) 2014 Elsevier Ltd. All rights reserved.