Question
Name the types of fuel pumps and explain them..
1. Gear type
Gear type pump is a positive displacement pump which takes on, inlet fuel and rotates in a direction which allows fuel to move between the gear teeth and pump inlet case until fuel is deposited in the outlet.
2. Multi-plunger/ swash plate type
This is a variable displacement pump driven by engine gear train. Output depends on rotational speed and pistons. Rotor assembly fitted with several plungers.End of plungers bear onto non-rotating cam plate and biased by spring to give full stroke position of plungers. servo pistons subjected to pump delivery pressure on one side and spring end servo pressure on the other. Variation in pressure difference across the servo piston causes it to move with corresponding variation in cam plate angle therefore piston stroke.