| 摘要 |
PURPOSE:To prevent creation of noise due to the motion of a fuel pump, by a method wherein the number of revolutions of the fuel pump is controlled so that its high harmonic component is present within the range of the given frequency of noise created by an engine during ilding of the engine. CONSTITUTION:The number of revolutions of a fuel pump 1 is detected by a detector 2 for the number of revolutions which outputs an output voltage proportional to the number of revolutions of the motor 1. A control circuit 3 is connected to the output terminal of the detector. Meanwhile, a voltage set circuit 4 generates an output voltage having a level depending on the load of an engine, and the output voltage is fed to the control circuit 3 which provides a control signal according to the output voltage of the detector 2 for the number of revolutions and that of the voltage set circuit 4. The drive circuit 5 of the motor 1 is connected to the output terminal of the control circuit 3, and the drive circuit 5 applies a voltage, having a level corresponding to the control signal, on the motor. The voltage applied on the motor 1 goes to a voltage proportional to the output voltage of the voltage set circuit 4, and thereby, during idling, the voltage applied on the motor 1 decreases, also resulting in reduction in the number of revolutions of the motor 1. |
