US Patent 9890689 Gaseous fuel combustion

In an internal combustion engine, gaseous fuel is injected in a first injection through a pre-combustion chamber into the combustion chamber to mix with air in the combustion chamber. The pre-combustion chamber has a jet aperture in fluid communication between the pre-combustion chamber and the combustion chamber. Mixed gaseous fuel and air is then ingested into the pre-combustion chamber from the combustion chamber and ignited. In a second injection, injecting gaseous fuel into the pre-combustion chamber and expelling, with the second injection, ignited gaseous fuel and air from the pre-combustion chamber through the jet aperture and into the combustion chamber as a flaming jet with a core of gaseous fuel.