Gaseous-fuelled stoichiometric compression ignition internal combustion engine

A method for operating a gaseous-fuelled stoichiometric internal combustion engine comprising:

• (a) determining by mass an amount of pilot fuel as a function of detected engine operating conditions;
• (b) determining by mass an amount of gaseous fuel to introduce into a combustion chamber as a function of detected engine load and based on a total energy desired minus energy associated with said amount of pilot fuel;
• (c) determining by mass an amount of exhaust gas recirculation from an engine exhaust system to an intake air system as a function of at least one of said engine load and/or another engine operating condition;
• (d) determining an amount of air required for stoichiometric combustion as a function of said amount of pilot fuel, said amount of gaseous fuel and said amount of exhaust gas recirculation;
• (e) controlling an exhaust gas recirculation system to direct a portion of said amount of recirculated exhaust gas through a cooler and then to said intake air system;
• (f) controlling a pilot fuel injector to inject said amount of pilot fuel directly into said combustion chamber;
• (g) controlling a gaseous fuel injector to introduce said amount of gaseous fuel into said combustion chamber where it forms a substantially homogenous mixture with said air and said recirculated exhaust gas;
• (h) controlling said intake air system to introduce said amount of air into said combustion chamber;
• and
• (i) igniting said pilot fuel by compressing an intake charge comprising said pilot fuel, said gaseous fuel, said intake air and said recirculated exhaust gas, whereby the combustion of said pilot fuel triggers the ignition and stoichiometric combustion of said gaseous fuel.