It's the same thing. The grid is the oil filter. The function of the oil filter is to filter out impurities, gums and moisture in the engine oil and deliver clean engine oil to all lubricating parts.
In order to reduce the frictional resistance between relative moving parts in the engine and reduce the wear of parts, oil is continuously transported to the friction surfaces of each moving part, forming a lubricating oil film for lubrication. The engine oil itself contains a certain amount of gum, impurities, moisture, and additives. During the operation of the engine, the introduction of metal debris, the entry of impurities in the air, and the generation of oil oxides gradually increase the amount of impurities in the engine oil. If the engine oil enters the lubricating oil circuit without being filtered, it will bring the impurities contained in the oil into the friction surface of the motion pair, accelerate the wear of parts, and reduce the service life of the engine.
Due to the high viscosity of the engine oil and the high content of impurities in the engine oil, in order to improve the filtering efficiency, oil filter generally has three levels, namely engine oil collector, engine oil primary filter and engine oil secondary filter. The filter collector is installed in the front oil pan of the oil pump and generally adopts a metal filter screen type. The crude oil filter is installed behind the oil pump and connected in series with the main oil duct. It mainly includes metal scraper type, saw dust filter element type, and microporous filter paper type. Currently, microporous filter paper type is mainly used. The oil fine filter is installed in parallel with the main oil duct after the oil pump, and there are mainly two types: microporous filter paper type and rotor type. The rotor type oil fine filter adopts centrifugal filtration without a filter element, effectively solving the contradiction between the oil's passability and filtration efficiency.