Today it is very common to find several types of oil filters. The problem is that as a general rule they are not interchangeable with each other, because each engine equips one or the other depending on the design it has. Therefore, we must be careful when change oil and filter, so as not to screw up in the process.
The first differentiation that we have to take into account is the oil filters armored o cartridge. Some key features when it comes to car maintenance. However, although these are the most common filters in conventional cars, there are many more variants that we can find in heavy vehicles and very high-end models.
According to its disposable parts
Armored or monoblock
First of all, we have the filters armored, which are also called monobloc. Its the most used today both in passenger cars and in industrial vehicles. It is a metal filter that is placed directly on the engine by means of a thread provided for this purpose. filter body and cartridge form a single set, which is replaced every time we change the oil in our car. They are generally used in cars with diesel engines, although they can be found in some gasoline engines.
These filters are characterized by having a bypass valve calibrated at a certain pressure. When the oil pressure exceeds a preset value, the valve opens allowing the oil to return to the return. In addition, they may also have non-return valve which ensures that the oil filter is emptied when the engine is switched off.
of cartridge
Second, we have the oil filters cartridge. They have a filter cartridge that is the part that we must replace at the same time that we change the oil. The casing itself must be cleaned and put back as it was, so the method to change this filter differs quite a bit regarding shielded oil filters.
Cartridge filters do not have a bypass valve like armored filters, since said valve is located in the fixed part of the filter element and that not replaced when performing maintenance. These filters are mainly used in gasoline engines, but each brand has its preferences in this regard.
According to your filtering method
By pressure or mechanical
The oil passes through the filter part thanks to the pressure with which the engine moves it and the oil pump. Its very frequent in normal passenger cars, whether cartridge or armored. In order not to have problems when they get clogged by too much dirt, it has the aforementioned bypass valve. When it exceeds a certain pressure, it returns the oil to the circuit to prevent the filter part from breaking or becoming dislodged, allowing all the particles it trapped to pass through before becoming clogged. Which would be much more damaging to the engine.
By centrifugation
As their name indicates, they use the centrifugal force to pass harmful particles on the filter side. These filters are usually cartridge filters since they only require the filter to be replaced when they have accumulated too much dirt. On some models it is also possible to clean the filter and replace it.
By sedimentation
These oil filters they are the simplest. They are based on the fact that the particles to be filtered are usually heavier than the oil itself. Therefore they will tend to be deposited by sedimentation in a deposit located at the bottom.
by magnetism
This type of oil filter not usually used in motors, because it is only responsible for removing the metal particles, which are detached from the friction between pieces. For this reason they are usually used in parts that do not generate other contaminants such as gearboxes with their own oil.
by pyrolysis
They are not usually used in normal vehicles. They are more typical of industrial machinery. They eliminate the residues that are in suspension in the oil with the temperature increase. That is, in the same way as ovens that have pyrolysis to clean their interior.
Depending on the material of the filter element
Of paper
They are the most ecological, although that does not mean that they do not have to be taken to a clean point, due to the large amount of toxic waste they have once used. It's about a paper with a certain level of porosity, pressing y accordion-folded.
Synthetic
Filters made with a synthetic filter element they are able to filter smaller harmful particles because their pores are somewhat narrower. In addition this material can last longer without degrading. Which is not to say that it takes longer to get clogged by waste.
with microcrystals
Oil filters with a filter element made from microcrystals are capable of removing much smaller particles. They are used in engines high end, which for their price can and should have much higher quality components. With them, the oil lasts in good condition for a longer time.
Where do the impurities that need to be filtered come from?
The oil degrades naturally with the operating temperature of the engine. But it is also that the oil enters in small quantities in the combustion chambers. Something normal considering that it must lubricate the piston going in and out of it at high speed. Because of this, part of the oil burns and generates small impurities that are accumulating. The bluish smoke that some cars emit is a symptom that too much oil is burned in this way.
The oil also degrades and generates particles with the high pressures and temperatures typical of the friction of certain parts. In addition to that, when the friction is very great and without the correct lubrication, they come off metallic particles. The oil filters of a vehicle must take care of all this and that is why the correct type must be chosen for each model. No one knows better than the manufacturers what is the right filter for each engine, gearbox or any other component. They have been subjected to tests in which they have been able to see what waste has been generated and what is the best way to dispose of it.