1. AbstractThe life of liquid droplets on a hot surface is not a linear function of the surface temperature. Contrary to common belief, targeting the injectors at the intake valves does not always result in the best evaporation of liquid fuel. Timing and targeting of the injectors has to be a function of intake valve surface temperature and opening.This paper will present some guidelines for design of cylinder heads, intake manifolds and injector targeting. Theoretical explanation of the fuel droplet life on the hot surface and its correlation to intake valve deposits and evaporation are discussed. The data presented will support the theoretical guidelines.