Burning of 5%, 10%, and 20% shared volume of n-butanol (B05, B10, and B20, where B05 represents 5% shared volume of n-butanol with 95% diesel fuel) with diesel fuel (DF) in a high load, light duty, turbo-charged diesel engine is reported. The aim was to compare the effects of the blends on the engine combustion characteristics and regulated emissions namely nitrogen oxides (NOx), unburned hydrocarbon (UHC), carbon monoxide (CO) and soot results from this study with a similar past study: (30% rapeseed oil methyl esters (RMEs) shared volume with similar diesel fuel admixed to 5% or 7.5% bioethanol). Using n-butanol shared volume, B05, B10 and B20 significantly improved the reduction of regulated emissions compared to the other study. In this study the reduction or increase percentage relative to DF was as follows at 75% load at 1500 rpm for B5, B10, B20 mixtures: soot reduction was 55.5%, 77.8%, and 85.1% respectively; CO reduction was 35.7%, 57.1% and 71.4%; NOx increase was 10.3%, 32.3% and 54.4%; UHC increase, 21.4%, 71.4%, 214% respectively. The premixed phase combustion was amplified and distinguishable with increase of shared volume of n-butanol in DF. The combustion cycles of the blends were more stable than the cycles of DF. (c) 2012 Elsevier Ltd. All rights reserved.