Disadvantage 2: The filtration efficiency is zero under special conditions;
There is a bypass valve at the bottom of the paper filter element, which is designed to ensure that the oil can be smoothly circulated back to the engine when the engine is cold-started with high oil viscosity or when the paper filter element is partially or completely blocked. oil flow channel. When the oil opens the bypass valve under the pressure of the oil pump, the oil circulating back to the engine through the bypass valve will not only not be filtered by the paper filter element, but will also filter out the large particles of impurities that have been filtered out by the paper filter element. It is flushed back into the engine through the bypass valve, which brings uninterrupted secondary wear to the engine. From the above two shortcomings, it can be seen that the impurities larger or smaller than the micropores of the paper filter element cannot be permanently filtered, but only those impurities that are equal to the micropores of the paper filter element and embedded in the micropores of the paper filter element can play a permanent role. The filtration effect is very low, so the filtration efficiency is extremely low.