Evaluating Gasoline Additives for Intake-Valve Cleanliness Using the Volkswagen Polo Engine

Running the Volkswagen Polo engine through a 40 h high-load - high-speed test cycle has proved to be a reliable screening test for evaluating different additives for intake-valve cleanliness. This engine has been found to be sensitive to the chemistry and composition of the additive.

Apart from the detergent/dispersant component, additional partly detrimental effects on the intake-valve deposits due to corrosion inhibitors were observed.

An optimized combination of detergent/dispersant, corrosion inhibitor and mineral oil carrier led to such low valve deposits that no need for a synthetic carrier could be shown.

The engine was also adequate for evaluating the capabilities of different market gasolines to inhibit valve deposits.