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AssigneeLucas Industries public limited company
InventorsDavid Williams, Stuart M. Briscoe, Keith Melbourne
Estimating the term…
The existence of an unacceptable vapor leak can be determined by monitoring the pressure within a fuel system of an internal combustion engine. Once the engine is switched off, a period is timed to allow pressure variations due to movement of the fuel to subside to an acceptable level. The fuel system is closed and a first rate of pressure increase is determined by measuring a first time taken for the pressure to rise by a predetermined amount. A leak of a predetermined size is then introduced and a second rate of pressure increase is determined by measuring a second time taken for the pressure to rise by a predetermined amount. The first and second times are then compared to detect whether or not an unacceptable leak exists.
A method of detecting an unacceptable vapour leak in a fuel system of a vehicle internal combustion engine, including a fuel tank containing liquid fuel comprising performing a fuel system pressure test while the engine is switched off, said pressure test comprising closing said fuel system and measuring a first rate of vapour pressure rise in said fuel system resulting from evaporation of fuel in the fuel tank, introducing a predetermined vapour leak into said fuel system and measuring a second rate of vapour pressure rise in said fuel system including a fuel tank containing liquid fuel, and comparing said first and second rates of pressure rise to detect the presence of an unacceptable vapour leak.
An apparatus for detecting an unacceptable vapour leak in a fuel system of a vehicle internal combustion engine including a fuel tank containing liquid fuel, said apparatus comprising:
Dependencies are inferred from the claim text.