Fuel blends that contain biodiesel are known to produce greater NOx (nitrogen oxide) emissions in diesel engine exhaust than regular diesel, and this is one of the key barriers to the wider adoption of biodiesel as an alternative fuel. In this study, a water-containing ABE (acetone-butanol-ethanol) solution, which simulates products that are produced from biomass fermentation without dehydration processing, was tested as a biodiesel-diesel blend additive to lower NOx emissions from diesel engines. The energy efficiency and the PM (particulate matter) and PAHs (polycyclic aromatic hydrocarbons) emissions were investigated and compared under various operating conditions. Although biodiesel had greater NOx emissions, the blends, that contained 25% of the water-containing ABE solution had significantly lower NOx (4.30-30.7%), PM (10.9-63.1%), and PAH (polycyclic aromatic hydrocarbon) emissions (26.7-67.6%) than the biodiesel diesel blends and regular diesel, respectively. In addition, the energy efficiency of this new blend was 0372-7.88% higher with respect to both the biodiesel-diesel blends and regular diesel. Because dehydration and surfactant addition are not necessary, the application of ABE-biodiesel-diesel blends can simplify fuel production processes, reduce energy consumption, and lower pollutant emissions, meaning that the ABE-biodiesel-diesel blend is a promising green fuel. 2013 Elsevier Ltd. All rights reserved.