Lesson 1/Learning Event 1
FIGURE 3. BELLOWS-TYPE ELECTRIC FUEL PUMP.
Electric, Bellows Type. The bellows-type electric fuel pump works basically the same as the nonpositive
mechanical pump. The difference is that it is driven by an electric solenoid rather than a mechanical
camshaft. Operation is as follows:
- As electric current is fed to the pump, the electromagnetic coil pulls the armature down, expanding
- The expansion of the bellows causes fuel to be drawn in through the inlet valve.
- As the bellows fully expand, a pair of contact points opens, switching off the electromagnet.
- The return spring pushes the armature back up, contracting the bellows. This action pushes fuel out
of the pump through the outlet valve.