Fuel Volatility Effects on Mixture Preparation and Performance in a GDI Engine During Cold Start
The objective of this research was to characterize the effects of fuel component volatility on gasoline direct injection (GDI) engine cold start. Three different fuel components, representing gasoline light end, mid-point and heavy end components, were used to form three fuel blends of different volatility. Performance tests and in-cylinder fuel distribution imaging tests using these fuel blends were carried out in a firing single-cylinder optically-accessible engine following a simulated cold start test schedule. Performance results, based on in-cylinder pressure and engine-out hydrocarbon measurements, during the initial transient phase of GDI cold start showed significantly degraded performance with the low volatility fuel blend, while the high volatility blend showed slightly improved performance. Neither the low nor high volatility fuel, however, showed a discernable effect on the quasi-steady state cold start performance.