Oil filter

Oil filter, also known as oil grid. Used to remove impurities such as dust, metal particles, carbon deposits, and coal smoke particles from engine oil, protecting the engine.

There are two types of oil filters: full flow and split flow. The full flow filter is connected in series between the oil pump and the main oil passage, so it can filter out all the lubricating oil entering the main oil passage. The shunt cleaner is connected in parallel with the main oil passage, and only the lubricating oil sent out by the filter oil pump is filtered.

During the operation of the engine, metal debris, dust, carbon deposits and colloidal deposits oxidized at high temperatures, water, etc. continuously mix into the lubricating oil. The function of an oil filter is to filter out these mechanical impurities and gum, maintain the cleanliness of the lubricating oil, and extend its service life. The oil filter should have strong filtering ability, low flow resistance, and long service life. In general, several filters with different filtration capabilities are installed in lubrication systems - collection filters, coarse filters, and fine filters, which are respectively connected in parallel or series in the main oil passage. The filter connected in series with the main oil passage is called a full flow filter, and all lubricating oil is filtered through the filter during engine operation; the filter connected in parallel with it is called a split flow filter. The coarse filter is connected in series in the main oil passage and is a full flow type; The fine filters are connected in parallel in the main oil passage and are of a split flow type. Modern car engines generally only have a collection filter and a full flow oil filter. The coarse filter is used to filter out impurities with a particle size of 0.05mm or more in engine oil, while the fine filter is used to filter out small impurities with a particle size of 0.001mm or more.

Technical characteristics

● 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. Under severe temperature fluctuations, the concentration of the oil also changes accordingly, which can affect the filtration flow rate of the oil. The filter paper of the oil filter should be able to filter impurities under severe temperature changes while ensuring sufficient flow rate.

Rubber sealing ring: The sealing ring of the oil filter is made of special rubber.

● Backflow suppression valve: only available in oil filters. When the engine is turned off, it can prevent the oil filter from drying out; When the engine is reignited, it immediately generates pressure and supplies oil to lubricate the engine. (also known as check valve)

● Overflow valve: Only available in the oil filter. When the external temperature drops to a specific value or when the oil filter exceeds its normal service life, the relief valve will open under special pressure, allowing unfiltered oil to flow directly into the engine. Despite this, impurities in the engine oil will enter the engine together, but compared to the damage caused by the absence of oil in the engine, such damage is much smaller. Therefore, the relief valve is crucial for protecting the engine in emergency situations.