FUEL EVAPORATORS

摘要

An evaporator (50) for the supply of an air/fuel mixture to a small engine consists of a flow duct (51) accommodating a stack of flat plates (52) having non-porous, non-reticulated surfaces and spaced apart by spacers (53) so as to define narrow passages for flow of air therebetween. Each of the spacers (53) is provided with through holes (54) extending through parts of the spacer (53) which have recesses (55) in their front and rear faces, the through holes (54) being aligned with corresponding holes (not shown) in the plates (52) to form fuel passages such that fuel supplied along the passages is emitted from the recesses (55) onto the evaporation surfaces transversely of the air flow supplied to the inlet of the flow duct (51) in the direction of the arrow (57), so that a fuel film (56) is produced on each evaporation surface having a thickness which reduces downstream of the supply point. Furthermore the air flow in the direction of the arrow (57) results in variation of the local air flow velocity (V) so as to produce a shear stress in the fuel film (56) which assists downstream spreading of the fuel, and evaporation of fuel from the fuel film into the air flow to produce a substantially uniform air/fuel mixture.