In a set of hydraulic system, as a power component, hydraulic pump has to go through several processes in its work. With A&S Hydraulic Co., Wesley, product application engineer of Ltd Technology Department, we can first take a look at the working process of Parker plunger pump in operation.
Parker plunger pump in the work is roughly divided into three processes: oil intake, oil supply and oil return.
Oil intake process:
When the cam protrudes somewhat after turning to the past, under the result of spring tension, the plunger moves downward, and the vacuum degree occurs in the upper space of the plunger (called pump chamber). When the upper end of the plunger opens the oil intake hole on the plunger sleeve, the diesel oil filled in the upper body of the oil pump enters the pump chamber through the oil hole, and the plunger moves to the lower stop point, and the oil intake is completed.
Oil supply process:
When the camshaft turns to the protrusion of the cam and some of the rollers are lifted, the plunger spring is tightened, the plunger moves upward, and the fuel is pressurized. Some of the fuel flows back to the upper body of the injection pump through the oil hole. When the top surface of the plunger covers the upper edge of the sleeve entering the oil hole, the pump chamber on the top of the plunger becomes a sealed oil chamber due to the small space between the plunger and the sleeve. The plunger rises continuously and the oil pressure in the pump chamber increases. When the pump oil pressure is greater than the spring tension of the oil outlet valve + the remaining pressure of the high-pressure oil pipeline, the oil outlet valve is pushed out, and the high-pressure diesel oil enters the high-pressure oil pipeline through the oil outlet valve and passes through the injection. The oil is injected into the combustion chamber.
Oil return process:
The plunger feeds oil upward. When the inclined groove (stop supply side) on the plunger and the return hole thunder on the sleeve are ascended, the low-pressure oil circuit of the pump chamber communicates with the middle and radial holes and inclined grooves of the plunger head. The oil pressure suddenly decreases, and the outlet valve closes down actively under the result of the tension spring force to continue the oil supply. Since then, the plunger has to go up. When the cam protrudes somewhat, the plunger goes down again as a result of the tension spring. Then the next cycle begins.
In operation, under the operation of cam and pump race spring on the camshaft of the fuel injection pump, the piston in the Park plunger pump moves up and down to achieve the purpose of oil intake, oil supply and oil discharge. This is the working principle of the Park plunger pump.