Patent ID: 6189516
Filing Date: 2001-02-20
Classification: F02M

Abstract:
A fuel vapour extraction system for an internal combustion engine (10) supplied with a volatile liquid fuel from a fuel storage tank (20), the engine (10) having an air intake system (12,14,16) and a liquid fuel injection system for dispensing fuel to mix with air to be burnt in the engine, the fuel vapour extraction system including a volatising chamber (30) connected to the fuel storage tank (20) by a valve (26) serving to maintain a constant liquid level of fuel in the chamber (30) and a vapour space above the liquid level in the chamber (30), and means (42) for drawing vapour from the vapour space in order to maintain a reduced pressure in the volatising chamber (30), the fuel injection system including a fuel circulation pump (32) for drawing liquid fuel from the volatising chamber (30) and supplying the fuel under pressure to a fuel rail (34), fuel injectors (18) for dispensing metered quantities of fuel from the fuel rail (34) to the engine cylinders, a relief valve (36) for maintaining a constant fuel pressure in the fuel rail (34) and a fuel return pipe (38) for returning unused fuel from the fuel rail (34) to the volatising chamber (30), characterised by means (40) within the vapour space of the volatising chamber for promoting evaporation of the return fuel by significantly increasing the surface area to volume ratio of the return fuel.