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Formation of Intake Valve Deposits in Gasoline Direct Injection Engines

Journal Article
ISSN: 1946-3952, e-ISSN: 1946-3960
Published October 17, 2016 by SAE International in United States
Formation of Intake Valve Deposits in Gasoline Direct Injection Engines
Citation: Guinther, G. and Smith, S., "Formation of Intake Valve Deposits in Gasoline Direct Injection Engines," SAE Int. J. Fuels Lubr. 9(3):558-566, 2016,
Language: English


Gasoline direct-injection (GDI) engines have a well-known propensity to form intake valve deposits (IVD), regardless of operator service, engine architecture, or cylinder configuration. Due to the lack of a fuel-washing process that is typical of Port Fuel Injected (PFI) engines, the deposits steadily accumulate over time and can lead to deterioration in combustion, unstable operation, valve-sticking, or engine failure. Vehicles using these engines are often forced to undergo expensive maintenance to mechanically remove the deposits, which eventually re-form. The deposit formation process has not been well-characterized and there is no standardized engine test to study the impact of fuel or lubricant formulation variables. To meet this need, a proprietary vehicle-based GDI-IVD test that is both repeatable and responsive to chemistry has been developed. Using a vehicle equipped with a 2.0L turbo GDI engine, the mechanisms leading to deposit formation have been studied and analyzed, and found to be a combination of engine oil, engine-wear elements, unburned fuel, and exhaust gas contaminants. The rate of accumulation was also found to be affected by engine lubricant formulation variables.