The Three Filter of Diesel Generator Set and its Functions

Aug. 20, 2021

The "three filters" of diesel generator sets refer to air filter, oil filter and diesel filter respectively. The "three filters" play a vital role in the normal operation of diesel generator sets. In this article, let’s take a look at their specific roles.

What is the Three Filter of a Diesel Generator Set and its Functions


1. Diesel filter

Diesel filter is a special pre-filtering equipment for diesel generators for internal combustion engines. It can filter out more than 90% of the mechanical impurities, gums, asphaltenes, etc. in the diesel, which can ensure the cleanliness of the diesel and prolong the use of the engine life. The use of a diesel filter can greatly improve the filtering accuracy and efficiency of the engine using a felt-type diesel filter, and can extend the service life of the diesel filter, and the fuel-saving effect is obvious.


2. Oil filter

1) Due to the high viscosity of the oil itself and the high content of impurities in the oil, in order to improve the filtration efficiency, the oil filter generally has three levels, namely the oil collector, the coarse oil filter and the fine oil filter. The filter collector is installed in the front oil sump of the oil pump, and generally adopts a metal filter screen type.

2) The coarse oil filter is installed behind the oil pump and connected in series with the main oil passage. There are mainly metal scraper type, sawdust filter type, and microporous filter paper type. Now the microporous filter paper type is mainly used. The fine oil filter is installed behind the oil pump and connected in parallel with the main oil passage. There are mainly two types: microporous filter paper type and rotor type. The rotor-type oil fine filter adopts centrifugal filtration and has no filter element, which solves the contradiction between oil passability and filtration efficiency.


3. Air filter

The function of the air filter in the diesel generator set is to filter out the dust that enters the air of the cylinder to ensure that the engine has enough clean air to mix with the fuel to produce combustion. The engine needs 14kg/air for every 1kg/diesel fuel burned. If it is not filtered, the dust falling into the air will greatly increase the wear of the cylinder, piston, and piston ring. Therefore, when the diesel generator set is working, it is not allowed to use the missing or damaged air filter. The requirements for air filters are: strong filtering capacity, low air resistance, simple structure, convenient use and maintenance.


We hope the above information about the function of the three filters of diesel generator sets is helpful to you. It is worth noting that the three filters of diesel generator sets must be maintained regularly. Otherwise its effect will be greatly reduced, or even damaged, affecting the normal operation of the unit.


Generator manufacturer-Guangxi Dingbo Power Equipment Manufacturing Co., Ltd is a reputable and leading generator manufacturer specializing the design, supply, commissioning and maintenance of diesel generator sets. Should you are looking for quality diesel generator, you are welcomed to contact us by

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