Commencement Of Main Injection Cycle
Shortly after the injection needle closes, the pressure again rises inside the high-pressure chamber. The injector solenoid valve remains closed and the pump piston moves downwards. At approximately 300 bar, the fuel pressure is greater than the force of the preloaded injector spring. The injector needle is again raised and the main injection quantity is injected. The pressure rises up to 2050 bar, because more fuel is displaced inside the high-pressure chamber than can escape through the nozzle holes. Peak pressure is at maximum engine speed and large injection quantity.