distributed evenly across the circumference by using an annular groove 9 inserted into the cylindrical ring slot 8 and guided to the injector tip the fuel reaches the inside of the injector tip via bores 17 inside the injector tip the fuel flows into the cavity 18 which is restricted by the valve needle 15 and the sleeve 14 the fuel flow in its path from the inlet 10 up the outlet from the valve 16 formed by the valve needle 15 and the cartridge 14 efficiently absorbs both the heat carried in the cylinder head 1 and the dissipated heat generated by the specific drive and in doing so becomes warmer the air gap 3 is suitably dimensioned if the heat carried in the cylinder head 1 remains as low as possible so that it only causes a temperature increase in the fuel of less than approximately 20 k as a result this ensures that the drive of the injector which is in the inside of the injector is efficiently cooled by the fuel by pass flow circulating around it under all the operating conditions a direct injector is insulated in a thermally active way from the cylinder head 1 by an encompassing air gap 3 having a gap width d 1 mm the following appraisal for the worst case scenario of the heat flow from the cylinder head 1 to the injector is now shown and compared in a for a production model engine and in b for a racing car.