Experimental Investigation of Carbon Nanotube Additives Effect on Performance and Emission of a High-Injection Pressure Common Rail Diesel Engine

Due to the continuous decrease in fossil fuel resources, and drawbacks of some biofuel properties, in addition to restricted environmental concerns, it becomes a vital manner to innovate some approaches for energy saving and emission reduction. One of the promising approaches is to enhance the fuel properties via adding nanoparticles. Carbon nanotubes (CNTs) blended with biofuels get extensive investigations by researchers using conventional diesel engines at relatively limited operating regimes. The objective of this work is to extend these studies using diesel fuel, rather than biofuels, on a high-injection pressure (1400–1600 bar) common rail diesel engine at wide operating conditions and higher CNT concentrations. Experimental results show an increase in peak pressure up to 24.46% than pure diesel when using 100 ppm CNTs concentration. Also, BSFC has decreased by 33.19%, and BTE increased by 54.2% compared to pure diesel fuel at high speeds and loads. NOx and CO₂ emissions raised by 24.3% and 23.3%, respectively, while CO emission decreased by 23.68%. These results could be a motivation for extra investigations for CNTs using smaller sizes, lower than 10 Nm, at wider engine regimes and particle concentrations.