Effects of 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. The impact of these inhibitors on spark ignited fuel systems, specifically intake valve deposits, is known and presented in open literature. However, the relationship of the additive concentrations to the powertrain intake valve deposit performance is not understood. This paper has two purposes: to present and discuss a market place survey of corrosion inhibitors and how they vary in concentration in the final blended fuel; and, to show how the variation in the concentrations of the CIs impact 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, were studied for their chemical compositions, and their impact on valves for a port fuel injection (PFI) engine. Gas chromatography data of Ed98 (100) ethanol and E85 blended fuels 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 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. Chemical analysis of the intake valve deposit materials will also be used to interpret the results.