Fuel Economy in Gasoline Engines Using Al2O3/TiO2 Nanomaterials as Nanolubricant Additives

What is it about?

Energy resources are of strategic interest worldwide. Transportation sector is a principal consumer of different energy resources, therefore reducing the consumption of vital energy resources is critical in automobiles. The friction and wear issues impact the energy efficiency of engines, therefore it is an important development of the lubricant for saving energy. The current study supports that goal. This study deals contribution of Al2O3/TiO2 hybrid nanoparticles as nanolubricants to improve gasoline engine efficiency and fuel economy. The gasoline engine performance characteristics were evaluated experimentally using an AVL dynamometer under different operating conditions including the New European Driving Cycle (NEDC). Additionally, the engine was tested under critical operating conditions (warm-up phase). The results showed that using Al2O3/TiO2 nanolubricants increases the brake power, torque, and mechanical efficiency, while the brake specific fuel consumption (BSFC) reduced owing to the mechanical efficiency of the engine improved by 1.7-2.5%, as compared to the engine oil without nanoparticles. Hence, the vehicle fuel consumption during NEDC could be improved up to 4 liters per 100 kilometers in the urban. Furthermore, FESEM, EDS line scanning, XPS, and Raman spectroscopy were conducted to understand the major tribological reasons for improving the engine performance to link tribological tests in the laboratory with actual engine performance. Eventually, the results suggest that nanolubricants provide economical engines with high efficiency that it may be an appropriate direction for vehicle manufacturers and users to suppress the engine fuel cost with engine durability under different operating conditions.

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Why is it important?

Conclusions and Recommendations Through the above experiments, Al2O3/TiO2 hybrid nanolubricants provided an improvement in the performance of gasoline engines at all operating points and NEDC driving cycle. These results proved to be systematic for fuel economy. The main conclusions are as follows: 1- The results exhibited that the brake power and engine torque increased with the use of Al2O3/TiO2 hybrid nanolubricants in all specific operative conditions, as compared to the lube oil without nanoparticles (5W-30). The reason is that the total frictional power losses decreased by 5-7% using hybrid nanolubricants. As a result, the mechanical efficiency of the engine improved in the range 1.7-2.5%. 2- The fuel consumption corresponding to Al2O3/TiO2 nanolubricants reduced by approximately 16-20%. Hence, the reduction in fuel consumption recorded during the NEDC test entails a fuel economy of about 4 L/100 km in the urban. 3- Al2O3/TiO2 nanolubricant accelerate the warm-up phase by 24% at same operating conditions due to improving the sensitivity of the lube oil to temperature. As a consequence, the reduction in fuel consumption by 4-10% was obtained. 4- The main reasons for improving the tribological performance are the rolling effect of the nanoparticles and tribofilm formation (~5 µm thickness) on the rubbing surfaces as illustrated by EDS mapping results. 5- The experimental results from EDS, XPS and Raman spectra indicated that the tribofilm contains not only the nanolubricant additives i.e. Al2O3 and TiO2 but Fe2O3 which is formed as a result of iron debris particles from rubbing surfaces causing strong bonding of the tribofilm with the sliding contact interfaces. 6- Further investigations are needed to how nanolubricants influence on the exhaust emissions from the engine at cold start, low load/speed operation when exhaust temperature may not be adequate for NOx reduction. Besides, study the nanolubricants effect on the heat transfer in the engine. This will be carried out in the near future.