What does PQ mean in vehicle safety inspection?

[JeffreyLynn]

PQ in oil testing refers to the amount of ferromagnetic particles contained in the oil, and the PQ value is also known as the mechanical wear index. The following is an introduction to PQ-related information: Instruments for measuring PQ values: There are specialized measuring instruments for PQ values, called PQ meters, also known as "ferrographs". Working principle of PQ: The working principle is that the tested oil sample is slowly and steadily transported by a double-tube infusion pump along the oil delivery pipe to the tray bracket above the magnet pole. The ferromagnetic wear particles in the oil are adsorbed on the center of the tray bracket surface under the action of a strong magnetic field. Meanwhile, the oil flowing through the strong magnetic field area is sucked back by the double-tube infusion pump along the oil return pipe, and then the inner wall of the oil delivery pipe and the center of the tray bracket surface are cleaned with a cleaning solution (such as tetrachloroethylene) that has strong solubility and good volatility.