The working principle of the plunger pump is that the total stroke L of the reciprocating plunger movement of the plunger pump is constant, which is determined by the lift of the plunger of the plunger pump. The amount of oil supplied to the plunger per cycle depends on the fueling stroke and the fueling stroke is variable regardless of camshaft control. The timing of the start of fuel supply does not change with the change of fueling schedule. Turn the plunger can change the fuel supply end time, thus changing the fuel supply. Piston pump at work, the camshaft in the fuel injection pump camshaft and the role of plunger spring, forcing the plunger up and down reciprocating motion, thus completing the task of pump oil, pump process can be divided into the following three stages. Piston pump works into the process of oil When the convex portion of the cam turn, under the action of the spring force, the plunger moves downward, the upper space of the plunger (called the pump chamber) to produce a vacuum, when the plunger The end of the plunger sleeve into the oil hole is opened, filled with oil in the upper body of the oil passage into the pump through the oil chamber, the piston moves to the bottom dead center, into the oil end. Plunger pump works Oil supply process When the cam shaft to the raised part of the cam top roller body, the plunger spring is compressed, the plunger upward movement, the fuel pressure, part of the fuel flow through the hole back to the injection pump body Oil chamber. When the plunger top cover the upper edge of the sleeve into the oil hole, due to the small clearance between the plunger and sleeve (0.0015-0.0025mm) so that the top of the plunger pump chamber becomes a sealed oil chamber, the plunger Continue to rise, the pump oil chamber pressure rapidly increased, pump oil pressure> spring force of the valve + high pressure tubing remaining pressure, open the valve, high pressure diesel oil into the high pressure tubing through the injector spray Into the combustion chamber. Piston pump working principle Back to the process of plunger oil, when up to the plunger on the chute (stop for the edge) and the sleeve connected to the oil return hole, the low pressure oil pump chamber and the plunger head Ministry of the hole and the radial hole and oblique groove communication, the sudden drop in pressure, the valve in the spring force quickly closed to stop the oil supply. After the plunger has to go up, when the convex part of the cam turn, under the action of the spring, the plunger down again. At this point they started the next cycle. Piston pump to a plunger principle, a plunger pump has two one-way valve, and the opposite direction, the plunger movement to a negative pressure within the cylinder, then a one-way valve to open the liquid is inhaled In the cylinder, when the plunger moves in the other direction, the other one-way valve after the liquid is compressed is opened, and the liquid sucked into the cylinder is discharged. This work continues after the formation of a continuous movement of oil.