When the piston moves upward, the volume expansion in the pump cavity forms true empty, so the check valve 2 is closed under the action of spring force, the check valve 1 is opened under the action of atmospheric pressure, and the liquid is sucked into the pump cavity through the oil inlet pipe; When the piston moves downward, the oil pressure in the pump chamber increases, close the check valve 1, push open the check valve 2, and the liquid is discharged through the oil outlet pipe. This is the working principle of the simplest single-cylinder piston pump. Repeatedly, the continuous oil delivery of the pump is formed. Necessary conditions for hydraulic pump operation:

1) The oil suction chamber and oil pressure chamber shall be separated from each other and have good sealing performance;

2) The working liquid is sucked in by expanding the volume of the oil suction chamber, and the liquid is discharged by reducing the volume of the oil pressure chamber;

3) When the oil suction chamber expands to the limit position, it should be cut off from the oil suction chamber first, and then transferred to the oil pressure chamber to ensure the continuous operation of the pump.

Description and operation specification of filter and manual pump
1) Install and connect the filter assembly to the engine oil supply system;

2) Loosen the oil drain screw of the filter base, press the pressure cap of the manual pump, and the manual pump will deliver the oil to the filter tank and the oil pipeline. At the same time, the gas in the system will be discharged until the diesel oil overflows at the oil drain screw. Tighten the oil drain screw, and then press the manual pump 3~5 times to complete the oil drain and pre-supply.

3) Turn on the car maintenance switch and check whether the water level sensor is normal.

4) Start the engine and check the filter for leakage.