Effects of multi-walled carbon nanotubes on the combustion, performance, and emission characteristics of a single-cylinder diesel engine fueled with palm-oil biodiesel-diesel blend

Multi-walled carbon nanotubes (MWCNTs) could be an effective fuel additive for 20 vol% palm-oil biodiesel in fossil diesel (B20) owing to its superior thermal conductivity. The effects of MWCNTs on the combustion, performance, and emission characteristics of B20 are investigated at various concentrations by a single-cylinder diesel engine under different engine speeds. The results show that B20 fuels with MWCNTs addition reduced the ignition-delay (ID), advanced the combustion phasing, and shortened the combustion duration by up to 17.6% (−2.6° CA), 12.9% (−1.8° CA), and 18.5% (−4.3° CA), respectively. The addition of MWCNTs in B20 also improved the brake specific fuel consumption (BSFC) and brake thermal efficiency (BTE) by up to 15.7% (−47.4 g/kW·h) and 16.3% (+4.6%), respectively. Compared with B20 fuel without MWCNTs, CO and UHCs emissions reduced by up to 34.7% (−8.2 g/kg-fuel) and 16.0% (−3.8 g/kg-fuel), respectively but NOx emissions increased by up to 43.5% (+7.6 g/kg-fuel). Overall, the results suggest that B20 with MWCNTs addition can enhance the combustion, performance, and emission characteristics of a light-duty diesel engine.