How the plunger works

Oil intake process

When the plunger goes from the bottom dead center to below the oil inlet hole, the fuel fills the pump oil chamber under the vacuum suction and the pressure of the oil transfer pump.

Pressure oil process

The camshaft is driven by the fuel injection timing gear to rotate. The cam on the camshaft drives the roller body to move up, and the roller body drives the plunger to move up.

When the pluger moves upward from the bottom dead center to close the oil inlet hole, the fuel pressure in the pump oil chamber will rise suddenly. Push open the oil outlet valve to reduce the high pressure oil pressure.

Into the high-pressure tubing.

Oil return process

When the plunger moves up to the spiral groove line or the upper line of the chute is higher than the lower edge of the oil inlet hole, the high-pressure oil flows back at high speed through the straight groove or center hole on the plunger.

Low pressure oil chamber. As the oil pressure in the pump oil chamber drops sharply, the oil outlet valve quickly returns to its position under the action of the spring and residual pressure, and the oil pump stops supplying Oil.The plunger continues to rise until the top dead center, which is the process of oil return.

diesel fuel pump plunger