MULTI-FUEL DELIVERY SYSTEM

A method for fuelling an internal combustion engine, and a fuel system (10) for delivering a variety of fuel types to the engine, with selected fuel types typically being chosen according to theft availability. The fuel system (10) can be configured to accommodate liquid fuels such as gasoline, ethanol or a blend thereof, and gaseous fuels such as CNG, LNG or LPG. The engine is configured to operate on any of the designated liquid fuels, and can switch between the liquid and gaseous fuels. The fuel system (10) includes a respective common delivery arrangement (11) for selectively delivering fuel into the combustion chamber of each cylinder of the engine. The common delivery arrangement (11) comprises at a fluid delivery device (12) and a liquid metering device (31) configured for operation in concert. The fluid delivery device (12) comprises a fluid delivery injector. Fuel is delivered to each combustion chamber is through the same fluid delivery device; that is, the same fluid delivery device (12) is used, regardless of the fuel type. More particularly, the fluid delivery device (12) can be used for delivery of gaseous fuel only, delivery of liquid fuel only (by way of an air assist delivery process), or delivery of a fuel mixture comprising the gaseous fuel and the liquid fuel according to the fuelling requirements of the engine at any time.