A fuel tank is a safe container for petrol or diesel fluids storage. There are one or some fuel tanks on the car.

The main function of the fuel tank is providing a mileage of 300 to 600 miles without refueling. The fuel tank 5 consists of two welded parts, stamped from leaded steel. There are partitions inside the fuel tank that prevent splashing of fuel and increase the rigidity of the structure.

Fuel tank Construction

a – general scheme of fuel tank; b – the exhaust valve open; c – intake valve open; 1 – gravitation filter; 2 – tank mounting bracket; 3 – tank clamp; 4 – fuel gauge; 5 – fuel tank; 6 – tap; 7 – filler cap;  8 – tank filler; 9 –  facing of filler cap; 10 – rubber gasket; 11 – plug housing; 12 – exhaust valve; 13 – exhaust valve spring; 14 – intake valve; 15 – tank plug lever; 16 – intake valve spring; 17 – tube; 18 – strainer.

A tank filler 8, closed by a fuel filler cap 7 is welded into the upper part of the tank. Also some cars have retractable tank filler neck to improve the fueling of the tank.  If the fuel tank neck is mounted on the side wall, then the upper part of the tank is connected to it by a pipe, through which air exits the tank when it is filled with fuel. There are a fuel gauge 4 on the upper wall of fuel tank and a tap 6 connected by a tube to the gravitation filter 1.

There is a tube 17 having a filter at the bottom and connecting to the tap 6 at the other end inside the fuel tank. A tank filter is installed in the bottom of the fuel tank, and a plug is screwed into the hole for lowering mechanical impurities and water settled to the bottom.

The trucks fuel tanks are installed using clamps 3 and brackets 2 on the left and right frame side members under the loading platform or driver’s seat. Fuel tanks of light cars are installed in the bottom of the trunk or under the floor of the car body.

The inside part of the fuel tank must be connected to the atmosphere because the pressure in the tank rises in summer. The fuel tank housing 11 has openings for connecting the fuel tank to the atmosphere. The central bore of the tank body is the seat of the exhaust valve 12.

The tight connection of the exhaust valve to the seat is provided by a spring 13 and a rubber gasket mounted under the valve flange. A spring 16 presses the intake valve 14 against the seat in the exhaust valve body.

The fuel from the tank is gradually consumed by the engine operation, so
there a vacuum is created and air begins to flow into the tank. If the pressure inside the tank increases, the exhaust valve 12 is activated. Vapors of a petrol through the hole in the plug exit into the atmosphere. The fuel tank cap is tightly held in the neck by levers 15.