The Effects of Fuel Composition and Fuel Additives on Intake System Detergency of Japanese Automobile Engine

The effects of fuel composition and additives (antioxidant and detergent) on intake system cleanliness have been studied using Japanese automobile engines equipped with EGR systems. The following conclusions were obtained.

Cleanliness of the intake system (carburetor and intake manifold) is influenced remarkably by the fuel characteristics, namely the olefin content and the type of antioxidant.

The detergent gives a large improvement in the cleanliness of carburetors and intake manifolds, but shows little or no effect on the intake valves.

A carrier oil used together with the detergent does reduce the deposit formation especially on the intake valves.

The increase of the aromatic content appears to augment the deposits on the cylinder head.