What does PQ mean in car safety inspection?

[DiJoseph]

PQ in oil testing refers to the amount of ferromagnetic particles in the oil, and the PQ value is also known as the mechanical wear index. Here is some related information about PQ: 1. Instrument for measuring PQ value: There is a special measuring instrument for measuring PQ value, called PQ meter, also known as "ferrograph". 2. Working principle of PQ: The working principle is that the tested oil sample is slowly and steadily transported by a double-tube infusion pump to the tray bracket above the magnet pole along the oil delivery pipe. The ferromagnetic wear particles in the oil are adsorbed on the surface center of the tray bracket under the action of a strong magnetic field. At the same time, 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 surface center of the tray bracket are cleaned with a cleaning liquid (such as tetrachloroethylene) with strong solubility and good volatility.