| 摘要 |
An in-tank motor-pump unit includes a motor driven gear pump, a pressure transducer, and a control module as a single integrated package establishing fuel flow at a constant pressure by creating a pulse-modulated motor drive having a fixed "off" and a variable "on" period. A permanent magnet DC motor drives a rotary pump with the required torque operating over the specified speed range and without stalling out at low flow demand. An integrated circuit board includes an IC timing chip, operating in an astable mode, has an input connected to the transducer and an output connected to a MOSFET switch which connects the motor to a power supply. A series resistor connects an amplified voltage signal of the transducer to charge the capacitor and discharge resistor separately connects the capacitor to the input of the timing chip to generate a constant "off" period and a variable operative "on" period of the MOSFET. A slight recycle fuel flow is established with substantially equal "on" and "off" periods at substantially zero fuel flow.
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