The pneumatic pump uses the compressed air to drive the piston back and forth, using the poor area of the upper and lower ends of the piston to obtain the high pressure fluid output. The output pressure of the liquid depends on the area ratio of the piston and the pressure of the driving gas. The piston area ratio is defined as the ratio of the pump and marked in the model of the pump. The fluid with different pressure output can be obtained by adjusting the working air pressure. When the oil and oil are pressed, the reciprocating motion of the plunger in the plunger sleeve is completed. When the plunger is located in the lower part, the two oil holes on the plunger sleeve are opened, and the inner cavity of the plunger sleeve is communicated with the oil passage in the pump body, and the butter is quickly filled into the oil chamber.
When the cam is pushed to the roller of the roller body, the plunger will rise. Move upward from the plunger to the oil hole and be blocked by the upper end of the plunger. During this period, as the plunger moves, the butter is extruded from the oil chamber and flows to the oil channel. So this is called a pre - stroke. When the plunger obstructed the oil hole, the oil pressure process began. The oil pressure in the oil chamber rises sharply in the plunger. When the pressure exceeds the spring force and the upper oil pressure of the oil outlet valve, the oil valve is lifted at the top and the grease is pressed into the oil pipe and sent to the fuel injector.