Contents lists available at ScienceDirect Applied Energy journal homepage: www.elsevier.com/locate/apenergy Fuel economy in gasoline engines using Al 2 O 3 /TiO 2 nanomaterials as nanolubricant additives Mohamed Kamal Ahmed Ali a,b,c , Peng Fuming a,b , Hussein A. Younus d,f , Mohamed A.A. Abdelkareem a,b,c , F.A. Essa e , Ahmed Elagouz a,b,c , Hou Xianjun a,b, ⁎ a Hubei Key Laboratory of Advanced Technology for Automotive Components, Wuhan University of Technology, Wuhan 430070, China b Hubei Collaborative Innovation Center for Automotive Components Technology, Wuhan 430070, China c Automotive and Tractors Engineering Department, Faculty of Engineering, Minia University, El-Minia 61111, Egypt d Chemistry Department, Faculty of Science, Fayoum University, Fayoum 63514, Egypt e Mechanical Engineering Department, Faculty of Engineering, Kafrelsheikh University, Kafrelsheikh 33516, Egypt f State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China HIGHLIGHTS • Fuel economy is improved by Al 2 O 3 / TiO 2 nanolubricants strategy under NEDC. • The vehicle fuel consumption during NEDC was reduced by 4 L/100 km. • The engine brake power and engine torque improved during urban and motorway. • Total frictional power losses of gaso- line engine were reduced by 5–7%. • The mechanical efficiency of gasoline engine improved in the range 1.7–2.5%. GRAPHICAL ABSTRACT ARTICLE INFO Keywords: Fuel economy Gasoline engines Warm-up phase Nanolubricants Nanomaterials NEDC driving cycle ABSTRACT 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 Al 2 O 3 /TiO 2 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 Al 2 O 3 /TiO 2 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 L per 100 km 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 https://doi.org/10.1016/j.apenergy.2017.11.013 Received 4 September 2017; Received in revised form 8 October 2017; Accepted 2 November 2017 ⁎ Corresponding author at: Hubei Key Laboratory of Advanced Technology for Automotive Components, Wuhan University of Technology, Wuhan 430070, China. E-mail addresses: eng.m.kamal@mu.edu.eg (M.K.A. Ali), houxj@whut.edu.cn (H. Xianjun). Applied Energy 211 (2018) 461–478 0306-2619/ © 2017 Elsevier Ltd. All rights reserved. T