Fuel injection device for an internal combustion engine

The fuel injection device has a feed pump (10) that delivers fuel from a reservoir (12) to suction side of the high pressure pump (16). The fuel is conveyed to a high-pressure region (18) through the high pressure pump. An injector (14) is arranged to supply the fuel from high-pressure region to a return line (20) which connects the high pressure region to a low pressure region. An energy converting unit (22) is arranged in the return line.