| 摘要 |
PURPOSE:To save electric power of a pump at light loaded operation, by controlling mean voltage applied to a motor of the fuel pump and also controlling a fuel delivery output of the fuel pump. CONSTITUTION:The emitter of a transistor Q1 is connected to the earth, and the base of a transistor Q2 is connected to the collector through a resistor R4. Power source voltage VB is fed to the emitter of the transistor Q2, while a motor M of a pump is connected to its collector. An integrating circuit 3, constituted by a resistor R5 and capacitor C1, is connected to the collector of the transistor Q2. An output of the integrating circuit 3, charged voltage of the capacitor C1, is connected to an negative input terminal of an operational amplifier OP in a comparator circuit 2. If the voltage VB is applied to the motor M, output voltage of the integrating circuit 3 is gradually increased. While if an output of the operational amplifier OP becomes a high level, voltage V1 is fed to a positive input terminal, and if the voltage of the integrating circuit 3 becomes larger than the V1, the output of the OP returns to a low level. |
