The Effect of Sulfated Ash Content in Lubricant Oil on Particulate Emission of Gasoline Engine

On a 1.5L TGDI gasoline engine bench(without GPF), 4 lubricant oils A/B/C/D with different sulfated ash content (1.1wt.%/0.8wt.%/0.7wt.%/0.5wt.%) were used to test the impact on the emission of PN and PM under WLTC condition.

In the test results, the PN and PM values of Oil A are the largest, 7.12E+12 p/km and 2.60mg/km respectively, the PN and PM values of Oil B and C are the equivalent, 5.58E+12 p/km&5.72E+12 p/km,1.81 mg/km & 2.03 mg/km respectively, and the PN and PM values of Oil D are 5.38E+12 p/km and 1.65mg/km respectively. The test results indicate that the sulfated ash content of engine oil affects the particulate emission level of the engine. Oil with high sulfated ash content(1.1 wt.%) has high emission values(PN&PM); Oils with low sulfated ash content (0.8wt.%) have lower emission values (PN&PM). When the sulfated ash content of the oil is below 0.8wt.%, there is almost no significant difference in emission values (PN&PM).