Dual-fuel internal combustion engine

The invention relates to a dual-fuel internal combustion engine (1) comprising a controller (2) for controlling the internal combustion engine and at least two piston/cylinder units (3), each of whichis paired with a fuel injector (4) for a liquid fuel, said fuel injector having an injector needle (5) that can assume different needle positions, and each of which is paired with a gas supply device(6) for gaseous fuel. The controller (2) is designed to actuate the fuel injector (4) and the at least one gas supply device (6) in an individual manner for selectively metering the quantity of liquid or gaseous fuel supplied to each of the at least two piston/cylinder units (3). For each of the at least two piston/cylinder units (3), at least one needle sensor (7) is provided which is connectedto the controller (2) and is paired with the respective piston/cylinder unit (3). A signal which characterizes the needle position in the ballistic region can be detected by the needle sensor so thatthe fuel injector (4) can be