How long can the oil filter last?

  Two questions:


   1、Whether it is necessary to change the filter at the same time when changing the oil


   2、Is it feasible to change the filter to extend the oil change time

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  In order to reduce the cost of car use, many car owners have made such attempts; however, the oil and filter always need to be replaced at the same time, unless the mileage is particularly low, and the "self-comforting" oil change according to the time period makes it unnecessary to replace the engine. filter. For example, if you drive 3000km every year, it is not a problem to replace the filter once every two years. Why do you say that?


  The function of the machine filter is to filter the impurities in the engine oil, as well as the normal standard metal chips worn during the operation of the internal combustion engine. How do these impurities arise and how to filter them?


  01


  The structure of the machine filter


   The "small black cylinder" removed from the chassis or dfsk auto engine compartment during car maintenance is the machine filter, but the machine filter is not a pure metal structure, but the shell and frame are made of metal.

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  From the filter installation position, you can see that there are many small round holes and a large round hole. There are threads in the middle of the big round hole; during installation, the thread inside the big round hole will be combined with the installation position, and this hole is the oil outlet.


On the contrary, the small holes around are the oil inlet holes. When the oil enters the oil holes, it will be in contact with the real filter element (filter paper); the oil filtered by the filter paper will flow from the round holes in the inner frame to the oil outlet holes. This is the filtering step .


   Figure 1: Oil hole


   Figure 2: Internal structure


  The filter paper of the filter is a material that does not have to worry about deformation or aging. Its materials are mostly composite materials of glass fiber, man-made fiber or wood pulp fiber; the manufacturing process includes infiltration, foaming, curing and forming filter paper. This kind of filter paper is retained Under the premise of filtering the pores, a layer of high temperature and corrosion resistant coating is formed on the surface.

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  The temperature that the filter paper can withstand is more than 300℃, so even if the pure engine oil has a certain degree of deterioration, it is unlikely that the filter paper will be damaged if it is soaked.


   Therefore, the filter does not have an absolute service life of its own concept. It is only whether the filter paper pores will be filled, or whether there is purification and filtration capacity, which is the main reference for judging the service life of the filter.


  The structure of filter paper is mostly "double-layer composite filter paper", and its concept is distinguished by the number of meshes as "combination of large and small meshes"; the outer filter paper is a coarse filter paper with large pores, and the inner filter paper is a finer filter.


  This is the design of the current mainstream machine filter element. Because the manufacturing cost is actually equivalent to that of the single-layer filter paper filter; therefore, the single-layer precision filter is basically eliminated, and the double-layer filter paper has a longer use. life.


  Because impurities with larger diameters will be stored by the coarse filter part, the service life of the fine filter part will be longer; the impurities generated during the operation of the internal combustion engine will not be many or very small, so as long as the fine filter element can still be used normally, this There is no problem when the filter is used for 10,000 to 20,000 kilometers.

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  02


   two filters


   1: The oil filter is the first filtration system and also the core structure. The function of oil not only includes lubrication and sealing, but also responsible for the cleaning of the engine;


  For example, the cleaning of sludge is the task of engine oil. The cleaned impurities will flow to the engine filter along with the engine oil, and then be filtered and stored by coarse and fine filter paper.


   As for the metal scraps in the wear area, there are not many. During the normal use cycle of the oil, the scraps produced will basically be filtered out by the two filter papers.


Even if the filter paper is filled with "impurities and metal chips" to a nearly "full" state, the amount of oil in the oil inlet hole will not change at this time, but the flow rate will be affected due to clogging; the result is that the filter bypass valve is opened, partially The unfiltered oil enters the oil outlet directly. What should I do if there are some metal chips?

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  2: Don't worry about these metal shavings, because the oil always returns to the oil pan of the crankcase, otherwise it will not be able to reciprocate oil supply.


   There is an oil drain screw in the oil pan. After it is removed, the oil can flow out under the action of gravity. When removing the screw, did you find that the screw has a "fluffy" feeling?

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  The "fluffy" thing on the screw is just worn away, but there is no metal shavings that can be completely filtered out by the machine. The oil drain screw is magnetic.


  So there is no need to worry about the service life of the machine filter at this point, because the impurities that are normally cleaned up will be filtered by two thick and thin filter papers. Generally, there is no habit of heating cars in place and excessive carbon deposits appear. The quality of the engine oil is even 10,000km. Still good; there are two storage systems for the remaining gold scraps, what else should I worry about?


  Summary: The service life of the oil filter can be directly referred to the service life of the oil. If the average annual mileage is too short and you are accustomed to changing the oil once a year, the oil filter can be extended. The normal mileage standard can refer to the following four standards, and there is no special need for other main issues.

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   Naturally aspirated mineral oil 5000km


   naturally aspirated semi-synthetic oil 7500-10000km


   Turbocharged semi-synthetic oil 5000km

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   Turbocharged, fully synthetic oil 10000km


   Measured standards for reference.


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