The Fuel Injection Pump, also termed the High-Pressure Fuel Pump in diesel engines,
is the core precision component of the fuel supply system in internal combustion forklifts.
Its primary role is to meter, pressurize, and deliver fuel to the injectors at precisely the right
time for combustion.
The pump's core tasks can be summarized as: "Right Quantity, Right Pressure, Right Time."
1.Suction Stroke: As the camshaft lobe rotates away, the plunger moves down by spring
force. This creates a vacuum, drawing fuel from the supply pump into the pump chamber.
2.Pressurization & Delivery: The cam lobe lifts the plunger. When the plunger closes the inlet
port, fuel in the chamber is trapped and compressed. Pressure rises drastically.
3.Fuel Injection: Once pressure exceeds the delivery valve spring tension and residual
pressure in the high-pressure line, the valve opens. High-pressure fuel travels to the injector
and is atomized into the cylinder.
4.End of Delivery: As the plunger moves further, its helical groove/control port aligns with a spill
port. High-pressure fuel vents back to the low-pressure side, causing an instantaneous pressure
drop. The delivery valve closes, ending injection.
