Effects of Gasoline Fuel Properties on Engine Performance

Beijing will implement the national 4^th stage emissions standards (equivalent to Euro IV emissions standards) in advance in China from 2008. The objective of this study was to provide some technical support for proposing automotive gasoline fuel standards matching with the emission standards.

In this paper, tests were conducted on two engines and one gasoline passenger vehicle meeting Euro III or IV emission standards to study the correlation between gasoline fuel properties and engine performances, including power, fuel consumption and emissions. Test results showed that the effect of octane number on engine power depended on engine technologies. High octane number had a negative effect on fuel consumption and emissions. As olefin content increased, the engine-out THC emissions decreased significantly. The vehicle test results also showed that high olefin content greatly reduced the tailpipe THC emissions. Aromatics content had little influence on emissions and catalyst conversion efficiency. During cold start process, as RVP increased, the THC emissions decreased, but the effect on CO emission changed with different engines. Sulfur had little effect on conversion efficiency of fresh catalyst, but had influence on the aging performance of catalysts.