A Method and System for Controlling the Fuelling of an Engine

A method and system (12) for controlling the injection of fuel into at least one cylinder (14) of an internal combustion engine (10) are provided. The system (12) includes a fuel injector (22), a temperature sensor (48), and an electronic control unit (ECU) (50). The fuel is parsed into a plurality of components based on the boiling points of elements of the fuel. The ECU (50) is used to store mass fraction values for each component relative to the total mass of a sample of the fuel along with vaporisation rates for each component. These values are then used by the ECU (50) to account for different vaporisation rates among fuel elements. The ECU (50) is further configured to adjust the mass fraction values responsive to the combustion air-fuel ratio and the engine temperature to account for the different volatility characteristics of various fuels.