On the Effect of Low-Viscosity Oil on Automobile Pollutant Emissions Based on Worldwide Harmonized Light Vehicles Test Cycle

In order to study the influence of low-viscosity oil on automobile pollutant emissions reduction, three different 0W20 oil samples were prepared with oil 5W30 as the base oil.

Parameters such as the oil viscosity, ash, and element content were tested at different stages, speeds, and accelerations of the Worldwide Harmonized Light Vehicles Test Cycle (WLTC). The results showed the effects of low-viscosity oil on exhaust emissions reduction were mainly concentrated in the low-speed and extra high-speed segment. At the low-speed segment, especially in the starting stage, carbon monoxide (CO), total hydrocarbon (THC), and non-methane hydrocarbon (NMHC) emissions can be reduced. The use of low ash oil can reduce nitrogen oxides (NOx) emissions; the methane (CH₄) emissions can be reduced by increasing the Zinc (Zn) content in engine oil moderately. The low-viscosity oil can reduce NOx emissions under the severe acceleration condition in the low- and medium-speed segment and the slow deceleration in the high-speed segment of WLTC.