Nanofuels: Combustion, engine performance and emissions

• Stable suspensions of nanoparticles of Al, Fe and B in diesel were used as fuels.
• These fuels showed reduced ignition delay, and longer flame sustenance.
• Specific fuel consumption reduced by 7% with nanoparticle modified fuels.
• Emissions of CO and hydrocarbons reduced, however NOx marginally increased.

Experimental investigation was carried out to study the burning characteristics, engine performance and emission parameters of a single-cylinder Compression Ignition (CI) engine using nanofuels which were formulated by sonicating nanoparticles of aluminum (A1), iron (F1) and boron (B1) in base diesel. These fuels showed reduced ignition delay, longer flame sustenance and agglomerate ignition. Study of engine performance at higher loads revealed drop in peak cylinder pressures and reduction of 7% in specific fuel consumption for A1 as compared to diesel. Improved combustion rates raised exhaust gas temperatures by 8%, 7% and 5% leading to increased brake thermal efficiencies by 9%, 4%, and 2% for A1, F1, and B1 respectively, as compared to diesel at maximum loading conditions. Volumetric reduction of 25–40% in CO emission, 8% and 4% in hydrocarbon emission was measured when the engine was fueled with A1 and F1 respectively as compared to emissions from diesel. However, elevated temperatures resulted into marginal rise in NOx emission.