Abstract: A self-igniting, mixture-compressing internal combustion engine for fuel gas includes a cylinder including a cylinder head (5); an insert (1) operably engaged with the cylinder head (5); a main combustion space (7) in the cylinder; and a prechamber (4) in the insert (1). A low-pressure fuel line is connected to the main combustion space (7). A nozzle (10) is at least partially disposed in the insert (1). The nozzle (10) is operably connected to a high-pressure fuel line. The nozzle (10) is used to inject fuel gas into the prechamber (4). At least one injection opening (6) for connects the prechamber (4) to the main combustion space (7) and passes the fuel gas from the prechamber (4) to the main combustion space (7).