Active pre-chamber jet-assisted H2 multi-mode combustion

The present disclosure is directed toward an engine system and a multi-mode combustion method for an internal combustion engine using hydrogen as a fuel. The engine system comprises a combustion system including a step-lipped piston bowl, a cover opposing the piston bowl, a hydrogen direct injector, and a radially asymmetrical pre-chamber partially opposite the lip of the piston bowl. The multi-mode combustion method includes injecting hydrogen and air a first time into the combustion system through the hydrogen direct injector, and jet igniting the fuel-air mixture in the combustion system. The injecting occurs during an intake stroke at low loads, and during a compression stroke at medium and high loads, Injecting hydrogen and air into the combustion system a second time via the hydrogen direct injector occurs either during or after jet-igniting, the hydrogen and air being at least partially ignited by compression.