Method for operating internal combustion engines

The present disclosure relates to a method for operating an internal combustion engine operating at least partly on gaseous fuel. The internal combustion engine has a main combustion chamber (8) and a pre-combustion chamber assembly (20) with a pre-combustion chamber (36), a gaseous fuel supply channel (46) for supplying gaseous fuel into the pre-combustion chamber (36), and an ignition fuel injector (34) for supplying ignition fuel into the pre-combustion chamber (36). The method may comprise supplying a predefined amount of gaseous fuel into the pre-combustion chamber (36) via the gaseous fuel supply channel (46) for enriching the pre-combustion chamber (36) with gaseous fuel at times between about 210° crankangle before the top dead center and about 180° crankangle after the top dead center, and supplying a predefined amount of liquid ignition fuel into the gaseous fuel enriched pre-combustion chamber (36) via the at least one liquid ignition fuel injector (34).