whether the determined charge has risen or fallen because the raised voltage value of the actuator dominates the value of the charge for a control operation by means of the energy e 2 stored in the injector the closed control loop from the time t 1 determines too high an energy value it will therefore reduce the charge supplied to the injector in order to lower the energy stored in the injector the lower energy stored in the injector will however subsequently lead to the injection of too low a quantity of fuel under these conditions therefore the energy quantity stored in the injector no longer correlates with the injection quantity fig3 shows a flowchart for calculating the energy stored in the injector here in step s 1 there is determined in each case for each injector a first voltage value u 1 a first charge value q 1 and a rail pressure p after a definable period after the end of the charging phase of the injector in step s 10 by means of the voltage u2014 and charge values determined in step s 1 a first energy value en 1 stored in the injector and a first capacity value c 1 are determined the energy amount en 1 stored in the.