Effects of Gasoline and Ethanol Fuel Corrosion Inhibitors on Powertrain Intake Valve Deposits

Corrosion inhibitors (CIs) have been used for years to protect the supply and distribution hardware used for transportation of fuel from refineries and to buffer the potential organic acids present in an ethanol blended fuel to enhance storage stability. The impact of these inhibitors on spark-ignition engine fuel systems, specifically intake valve deposits, is known and presented in open literature. However, the relationship of the corrosion inhibitors to the powertrain intake valve deposit performance is not understood. This paper has two purposes: to present and discuss a second market place survey of corrosion inhibitors and how they vary in concentration in the final blended fuel, specifically E85 (Ethanol Fuel Blends); and, to show how the variation in the concentrations of the components of the CIs impacts the operation and performance of vehicles, specifically, the effects on intake valve deposit formation. Commercially available corrosion inhibitor packages for both gasoline and ethanol blended fuels, specifically E85 fuels (Ethanol Fuel Blends), were studied for their chemical compositions, and their impact on valves for a naturally aspirated port fuel injection (PFI) engine. Gas chromatography data of E85 blended fuels (Ethanol Fuel Blends) with CIs will be shown and discussed. The PFI engine dynamometer tests were performed in a designed fashion to understand repeatability in the data. This is important due to the wide range in corrosion inhibitor concentration that has been discovered in the market data. Chemical analysis data of the fuels with CIs will be used to explain the intake valve deposit results. Further method developments are ongoing to study the fatty acid portion of the corrosion inhibitor package and its possible contribution to the intake valve deposits.