Applications of Nano-Additives in Internal Combustion Engines: A Critical Review

Abstract

This paper highlights the applications of nanotechnology that are used in internal combustion engines in terms of nanofluids. Nanofluids are prepared by dispersing or blending nano-sized particles in a base fluid (viz., H2O, lubricant oil, glycol, biodiesel, diesel, etc.) to achieve desirable attributes in a specific field. The addition of nanoparticles to any base fuels causes thermo-physical and thermochemical properties changes, which are the foremost requisite in most engineering applications. In this paper, the applications of nanoparticles in internal combustion engines have been discussed in-depth in terms of catalytic applications, thermochemical properties, emission, and performance attributes of diesel engines, etc. Recent information reveals that the existence of nanoparticles is widespread as it plays a vital role in modifying the fuel properties (namely, calorific value, cetane number, density, viscosity, flash point, fire point, etc.). In some research attempts, nanoparticles are also considered as coolant in internal combustion engine applications, irrespective of fuels used in power generation. Several researchers have recently introduced nano-additives (such as alumina, carbon nanotubes, zinc oxide, aluminum) to serve as a fuel-borne catalyst to boost internal combustion engine functionality. It has also been reported that nanoparticles enhance performance and reduce harmful pollutants compared to pure fuels (such as pure diesel and pure biodiesel). Superior surface/volume ratio and catalytic/chemical reactivity are vital attributes of nanoparticles, influencing researchers and scientists to utilize them in the internal combustion engine applications.