The invention concerns a method for regulating the injection of fuel into a heat engine of a generator set including an alternator driven by the heat engine, the alternator including a voltage regulator, the heat engine including a speed regulator having an inlet that can receive an external speed setpoint, the method including the following steps: detecting a variation in torque and kinetic energy from electrical measurements on the alternator, carrying out an action on the input of the setpoint of the voltage regulator and/or the speed regulator, on the basis of the magnitude of the variation in torque relative to the kinetic energy level.