How the fuel injection pump works:
The fuel pump sucks fuel from the mailbox pump, passes through the fuel filter with the oil-water separation device, and reaches the fuel inlet of the fuel injection pump. The oil pump allows the fuel to enter the lubrication and cooling circuit of the high-pressure pump through the orifice of the safety valve. The pistons of the three pumps are moved up and down according to the profile of the cam.
When the Guangxi plug of the high-pressure pump moves downward (suction stroke), the oil pump makes the fuel enter the plunger rubber through the high-pressure pump oil inlet proportional valve and the stepped oil return valve. After the plunger of the high pressure pump has passed the bottom dead center. In this way, the fuel in the guise rubber is widely sealed and will be compressed by the oil pressure higher than the supply pressure. Once the oil pressure rises to the common rail oil pressure, the outlet valve opens and the compressed fuel enters the high pressure cycle. The plunger continues to supply oil until it reaches the top dead center (fuel supply stroke), the pressure drops, causing the oil outlet valve to close, the fuel pressure still in the plunger cavity also drops, and the plunger moves down again. Once the pressure in the plunger chamber falls below the supply pressure of the oil pump, the oil inlet valve will open again and the oil suction process will begin again.
