into the pump work chamber 6 during this intake stroke has two components first a positive displacement by the reservoir piston 14 out of the reservoir chamber 13 and second as a supplement thereto the supply effected by the supply pump 7 as a result it is possible briefly to effect a supply augmentation volume per unit of time which is far beyond that which the supply pump 7 alone is capable of providing the supply pump 7 may accordingly be made small in size since the reservoir can serve to supply extraordinary needs rather than the pump directly in each case however the reservoir pressure 13 must be greater than the pressure required for restoring the initial position of the piston 5 this pressure level is determined by hysteresis and by the counterpressure which arises in the mechanism the supply conduit 8 is capable of being shut off by the magnetic valve 9 so that the reservoir piston 14 is then displaced into its outset position and the engine rapidly comes to a stop because the fuel supply has been cut off various working positions of the apparatus are shown in fig1 4 for better understanding of the invention fig2 4 have been simplified to show pertinent details only in particular the cam 3 is illustrated therein as a roll off curve fig2 illustrates the beginning of the compression stroke of the pump piston 5 for which the roller 4 rolls off on the particular edge of the cam 3 which effects a compression stroke at the beginning of the compression stroke there is also a connection via the groove 11 to the bore 18 and thus to the annular conduit 17.