Tax strategy for better use of fuel in a gas engine

摘要

A method of operating a fuel delivery system in a vehicle having an engine capable of burning gaseous fuel supplied to a direct injection valve of the engine from at least a first and a second source, the first source having a higher source pressure than the second source, the method comprising: Supplying gaseous fuel from at least the first source to the direct injection valve during a first engine demand; and supplying gaseous fuel from at least the second source to the direct injection valve during a second engine demand below the first engine demand.