Introduction To Oil Filter

In the course of engine work, metal abrasives, dust, oxidized carbon, and gum deposits at high temperatures, water, etc. are constantly mixed into the lubricating oil. The role of the oil filter is to filter out these mechanical impurities and gums to ensure the cleanliness of the lubricating oil and extend its service life. The oil filters should have strong filtering ability, small flow resistance, long service life, and other properties. The general lubrication system is equipped with several different filtering ability filters - set filter, coarse filter, and fine filter, respectively, parallel or series connection in the main oil channel. (In series with the main oil channel called the full-flow filter, the engine work when all the lubricant is filtered by the filter; and the parallel connection is called the diversion filter). The coarse filter is a series connection in the main oil channel, for the full-flow type; the fine filter parallel connection in the main oil channel, for the diversion type. Modern car engines are generally equipped with only a set of filters and a full-flow oil filter. A coarse filter to filter out the oil particle size of 0.05mm or more impurities, and a fine filter is used to filter out the particle size of 0.001mm or more fine impurities.

Technical characteristics of the oil filter

Filter paper: Oil filters have higher requirements for filter paper than air filters, mainly because the temperature of the oil varies from 0 to 300 degrees, and the concentration of the oil changes accordingly under the drastic temperature change, which affects the filtering flow of the oil. The filter paper of a high-quality oil filter should be able to filter impurities under drastic temperature changes and at the same time ensure a sufficient flow rate.

Rubber seal: The filter seal of high-quality oil is made of special rubber synthetic to ensure 100% no oil leakage.

Backflow inhibitor valve: Only available in high-quality oil filters. When the engine is off, it prevents the oil filter from drying out; when the engine is restarted, it immediately generates pressure to supply oil to lubricate the engine.

Overflow valve: Only available in high-quality oil filters. When the external temperature drops to a specific value or when the oil filter exceeds its normal service life, the relief valve opens under special pressure, allowing unfiltered oil to flow directly into the engine. Although the impurities in the oil will thus enter the engine together, the damage is much less than that caused by the absence of oil in the engine. Therefore, the relief valve is the key to protecting the engine in case of emergency

Disadvantages of oil filters

Although there are some unavoidable disadvantages of oil filters, a good oil filter still plays an important role, such as the Cat C7 oil filter can give you a good user experience.

Disadvantage one: only 60% of the impurities in the oil can be filtered out, low filtration efficiency.

This is due to the current oil filter, which relies on a single paper filter element pore interception to filter out harmful impurities in the oil, the smaller the micro-pore of its filter paper the better the filtering effect, but the worse the oil through the ability. In order to solve the contradiction the smallest particles of impurities can be filtered out on the same filter paper pore, and a sufficient amount of oil can be supplied to the engine through the pore. The filter branch of the National Association of Internal Combustion Engine Industry, using the oil filter filtration efficiency ISO4548 international standard test method shows that: even the best oil filter on the market can only be designed to filter out 60% of the impurities in the oil, which is the maximum filtering value after thousands of experiments. In actual use, there are 40% of harmful impurities cannot be effectively filtered out by the paper filter element. In this 40% of impurities, because the ferromagnetic impurities are relatively small and hard, so the ferromagnetic impurities are the majority, and it is the most damaging to the engine.

Disadvantage two: zero filtering efficiency under special conditions.

In the existing use of oil filters, the bottom of the paper filter element is equipped with a bypass valve, which is designed to take into account the engine in the cold start oil viscosity or paper filter element is partially blocked or completely blocked, to ensure that the oil can be smoothly circulated back to the engine and the design of the direct oil flow channel. When the oil opens the bypass valve under the pressure of the oil pump, the oil circulated back to the engine by the bypass valve will not only not be filtered by the paper filter element, but also the large particles of impurities that have been filtered out by the paper filter element will be washed back to the engine by the bypass valve, which will bring uninterrupted secondary wear to the engine, so the oil filter used in the market can play a filtering role under special conditions, so the filtering efficiency is zero.