Fuel Injection: Pump Working Principle - Animation

The primary working principle of a fuel injection pump involves using a reciprocating inside a barrel to pressurize and meter fuel before delivering it to the engine cylinders . In a standard mechanical setup, a camshaft drives the plunger up and down, while a control rack rotates the plunger to adjust how much fuel is injected per stroke.

: To stop injection, a helical groove on the plunger eventually uncovers a spill port . This allows pressurized fuel to "spill" back into the lower-pressure gallery, causing the delivery valve to close instantly. Fuel Injection pump working principle - Animation

: In modern systems, an Electronic Control Unit (ECU) uses signals to trigger high-pressure solenoid valves , replacing the mechanical rack and governor for more precise control. The primary working principle of a fuel injection

The difference between and indirect injection nozzles. This allows pressurized fuel to "spill" back into

: As the plunger reaches the bottom of its stroke, fuel from the supply tank floods the barrel through inlet ports .