Page 190 - Mechanic Diesel - TT

MECHANIC DIESEL - CITS

Study about oil filtering systems

Objectives: At the end of this lesson you shall be able to
• explain about oil filtering systems.

Oil Filter System
When the oil returns after lubricating all the parts of the engine, it brings with it the dirt and fine metal particles
of the engine parts. If this dirt or metal particles go back between the engine parts with the oil, then the rubbing
parts will start wearing out quickly and the oil passages may also get blocked due to the dirt, which will stop the
lubrication of those parts. Therefore, it is necessary to clean this dirty and metal particle mixed oil. For this, an oil
filter system is arranged between the oil pump and the main oil gallery.
Two types of systems are used to filter engine oil.

• Full flow Oil filter system
• Bypass Oil Filter System
Full flow Oil Filter system: In this system the oil passes through a filter before reaching the main oil gallery. The
filter has a bypass valve which lets the oil pass directly to the main oil gallery in case the filter gets choked.

Bypass Oil filter system: In this system only a part of the engine oil enters the filter. After filtering, the oil reaches
the oil sump. The remaining oil is directly transported to the main oil gallery.
Filter Element: The filter is made of felt, cotton waste, cloth and paper. It is replaced after the engine has run a
certain distance of kilometers, as specified by the manufacturer.
Types of Oil Filter
Oil filters are of the following types
• Cartridge type oil filter

• Centrifugal type oil filter
1 Cartridge type oil filter: The oil filtered through this oil filter goes back to the engine parts. In this filter also,
like the fuel filter, a fine mesh of paper and wire is used as the filter element. This element is enclosed in a
casing in which separate passages are made for the oil to come in and the filter to go out. A drain plug is fitted
at its bottom, which is opened to take out the dirty oil.

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CITS : Automotive - Mechanic Diesel - Lesson 47 - 56 CITS : Automotive - Mechanic Diesel - Lesson 47 - 56