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.
: 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. Fuel Injection pump working principle - Animation
: When the pressure is high enough to overcome the spring force of the delivery valve , it snaps open, sending a high-pressure pulse of fuel through the lines to the injectors. The primary working principle of a fuel injection
: When you press the accelerator, a control rack rotates the plunger. This changes the position of the helix, determining how long the spill port stays covered and, consequently, how much fuel is delivered to the cylinder. Common Pump Types in Animations : When the pressure is high enough to
: 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.