The deposition of carbon particles present in fuel on engine valves can lead to a decrease in engine performance and lifespan. Broadly, the aim of this project was to investigate the role of various types of detergent and carrier fluid molecules in the dispersion and stabilisation of carbon particles in both fuels and lubricants oils. The project, divided into the following four stages, is now complete.

1. Investigation of the 'complexation' of various detergent and carrier fluid molecules.

2. Establishment of adsorption isotherms for the detergent and carrier fluid molecules separately and in combination, from hydrocarbon solvents onto carbon particles and steel beads. Some AFM experiments have also been carried out.

3. Deposition experiments of carbon particles onto steel in the presence of various combinations of detergent and carrier molecules using a 'home-made' flow-cell.

4. Ellipsometric studies of the detergent/carrier fluid layers at the solid-liquid interface.