between the suction grooves 13 and the suction port 14 is interrupted accordingly when the main discharge port 21 is brought into alignment with one of the distribution holes 23 the fuel introduced into the working chamber 12 is delivered under pressure through the axial channel 16 the radial passage 19 the main discharge port 21 and said one distribution hole 23 into one of the outlet passages 24 the fuel then passes through a corresponding one of the delivery valves 25 into an injection nozzle now shown by which it is injected into one of the engine cylinders on the other hand as shown in fig3 during the pressing stroke when the preliminary discharge port 22 faces the distribution hole 23 in advance of the main discharge port 21 preliminary fuel injection is effected in the same manner as described above with respect to the main fuel injection this preliminary fuel injection becomes impossible when the preliminary discharge port 22 is held out of alignment with the distribution hole 23 with which the main discharge port 21 is aligned thereafter as shown in fig4 these two operation modes are controlled by a preliminary fuel injection control device or timer 26 described below the timer 26 as shown in fig1 comprises a first.