The impact of adding nano-Al2O3 and nano-ZnO to Iraqi diesel fuel in terms of compression ignition engines' performance and emitted pollutants

Iraq's diesel fuel has high sulphur content due to the failure of refineries and the underlying quality of the feed crude oil. Aluminum oxide and zinc oxide nanoparticles were added to conventional Iraqi diesel to evaluate on the performance and pollution of a diesel engine not equipped with exhaust gas post-treatment equipment. Before the experiments, the fuel was mixed with the nanoparticles in specified quantities (50 ppm and 100 ppm), and samples of the mixtures were subjected to several tests. Measurements of the mixtures' thermophysical properties showed that the density, viscosity, and thermal conductivity of the suspension increased. Stability tests showed that these mixtures remained stable for at least two months indicating the success of the mixing process. The specific fuel consumption decreased and thermal efficiency increased when nanoparticles were added. This effect increased as a function of nanoparticle dose. Carbon monoxide, unburnt hydrocarbons, and all kinds of particulate matters, sulphur dioxide and hydrogen sulphate decreased with nanoparticle addition. NOx has increased because of higher generated temperature inside the combustion chamber as a result for nanoparticles addition. The results indicated that adding 100 ppm of nano-alumina gave the best results: It reduced specific fuel consumption by 8% and increased the brake thermal efficiency by 6%. The 100 ppm nano-alumina decreased CO, HC, TSP, SO2, and H2S by 17%, 17%, 26%, 19% and 19%, respectively. The NOx increased by 10%. The study results indicate a significant improvement in engine performance and a clear reduction in most emissions. In the future, the method proposed by the study will play an important role in improving unmodified diesel engine outputs using Iraqi diesel with nanoparticles addition.