The fuel fine filter is designed to remove the smallest mechanical particles from it that did not linger in the coarse filter;
- consists of a housing 8, two caps 4 with two paper filter elements 5 installed in the caps and sealed with rubber gaskets at the top and bottom
Under the pressure created by the booster pump, the fuel enters the cavities between the walls of the caps and the filter elements.
Passing through the pores of the filter curtain, the fuel is cleaned and collected around the central rod.
From here, the purified fuel exits the filter through the channels in the bolt shaft 7 and the housing to the high pressure fuel pump (high pressure fuel pump).
Since the fine filter is installed above all other devices of the power system, the air that has entered the system accumulates in it, which, together with part of the fuel, is discharged through the jet valve 9 into the fuel tank.
The jet valve starts to move and opens the passage for air and fuel vapors through channel B to the drain fuel line at a pressure in cavity A equal to 25...45 kPa.
When starting a cold engine in winter, the pores of the filter curtain may become clogged with ice crystals and paraffin flakes, which can form in diesel fuel at low temperatures.
In this case, the pressure at the inlet to the filter increases and, when it reaches 200...240 kPa, the fuel is bypassed through the jet valve from cavity A to channel B and further through the drain fuel line to the tank.
Thus, the jet valve protects the filter elements from destruction.
The opening pressure of the valve is regulated by the selection of washers 12 inside the plug 11.
If the filter elements are highly clogged, the fuel will also drain freely into the tank.
This reduces the fuel supply to the high-pressure pump, resulting in reduced engine power or shutdown.
To change filter elements you need:
- - unscrew the drain plugs two or three turns and drain the fuel from the filter into the dishes, then screw in the plugs;
- - unscrew the bolts securing the filter caps, remove the caps and remove the contaminated filter elements;
- - wash caps with diesel fuel;
- - install a new filter element with gaskets in each cap;
- - install caps with elements and tighten bolts;
- - start the engine and check the filter for leaks
Remove fuel leakage by tightening cap bolts