40 impacts the adjusting nose 42 the metering head 32 together with the metering valves 30 31 moves in the direction toward the combustion chamber 1 and the metering valves 30 31 open upon openings of the metering valves 30 31 a predetermined amount of the liquified fuel gas is injected in each of the fore chamber 21 and the main chamber 22 the cam 40 has in the circumferential direction of the cam plate 39 a relatively small length therefore the corresponding injection process is rather short after the injection the metering head 32 together with the metering valves 30 31 moves away from the combustion chamber the metering valves 30 31 close and are again filled with the liquified gas meanwhile the cam 41 impacts the adjusting nose 42 and against the metering head 42 together with the metering valves 30 31 moves in the direction toward the combustion chamber 1 because the length of the cam 41 in the circumferential direction of the cam plate 39 is greater than that of the cam 40 the metering head 32 is pressed against the cylindrical wall 2 of the combustion chamber 1 for a longer time as a result the metering valves 30 31 are likewise open for a longer time resulting in additional.