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The working principle of the plunger fuel injection pump

2023-08-10

When the convex part of the cam turns over, under the action of the spring force, the plunger moves downward, and the space above the plunger (called the pump oil chamber) generates a vacuum. When the upper end of the plunger puts the plunger on the inlet After the oil hole is opened, the diesel oil filled in the oil passage of the upper body of the oil pump enters the pump oil chamber through the oil hole, and the plunger moves to the bottom dead center, and the oil inlet ends.

The plunger supplies oil upwards. When the chute on the plunger (stop supply side) communicates with the oil return hole on the sleeve, the low-pressure oil circuit in the pump oil chamber will connect with the middle hole and radial hole of the plunger head. And the chute communicates, the oil pressure drops suddenly, and the oil outlet valve closes quickly under the action of the spring force, stopping the oil supply. Thereafter the plunger will also go up, and after the raised portion of the cam turns over, under the action of the spring, the plunger will go down again.

The plunger pump is introduced based on the principle of a plunger. There are two one-way valves on a plunger pump, and the directions are opposite. When the plunger moves in one direction, there is negative pressure in the cylinder. At this time, a one-way valve opens and the liquid is sucked. In the cylinder, when the plunger moves in the other direction, the liquid is compressed and another one-way valve is opened, and the liquid sucked into the cylinder is discharged. Continuous oil supply is formed after continuous movement in this working mode.