Piston pump working principle introduced
Piston pumps are essential components in hydraulic systems, widely used due to their high operating voltage, ease of flow regulation, and efficiency. These pumps operate through three main processes: the suction phase, the fuel delivery phase, and the return phase.
During the suction process, as the camshaft rotates and its convex part lifts the roller, the plunger moves downward under spring force. This creates a vacuum in the pump chamber above the plunger. When the plunger's upper face aligns with the oil inlet hole on the sleeve, diesel fuel from the supply line enters the chamber through the hole. The plunger reaches the bottom dead center, completing the suction stage.
In the fuel delivery phase, the cam continues to lift the plunger, compressing the spring and forcing the plunger upward. As the plunger rises, fuel is pressurized. Initially, some fuel flows back through the hole into the upper oil passage. Once the plunger covers the oil inlet hole, the small clearance between the plunger and sleeve (0.0015–0.0025 mm) seals the chamber. Further upward movement increases pressure, overcoming the spring force of the discharge valve and the resistance in the high-pressure tube. The valve opens, allowing high-pressure fuel to be injected into the combustion chamber via the nozzle.
The return phase begins when the plunger reaches a groove on the sleeve, connecting the pump chamber to the return oil hole. This sudden pressure drop causes the discharge valve to close quickly under spring force, stopping fuel delivery. As the cam rotates again, the spring pushes the plunger down, starting the next cycle.
The basic working principle of a piston pump relies on the reciprocating motion of the plunger. Two check valves are installed—one for suction and one for discharge. When the plunger moves backward, it creates a negative pressure, drawing fluid into the cylinder. When it moves forward, the other check valve opens, allowing the compressed fluid to be discharged. This continuous cycle ensures a steady flow of liquid.
Proper maintenance is crucial for long-term performance. If the plunger shows signs of corrosion, it should be replaced immediately. Checking the tightness of the plunger and inspecting the tappet are also important steps. Understanding the working principle of a piston pump helps in identifying potential issues early, ensuring reliable operation and extending the pump’s lifespan. Regular checks and timely maintenance are key to maintaining optimal performance.
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