Pic. 2.215. Fuel tank: 1 - fuel tank; 2 - mounting holes; 3 - the neck of the filling hole; 4 – a fixing collar of a bulk mouth; 5 - brackets for fastening brake pipelines; 6 - fuel supply pipeline; 7 - pipeline for supplying gasoline vapors; 8 - pipeline for removing gasoline vapors to the adsorber (coming from the fuel tank); 9 - communication with the atmosphere; 10 - adsorber; 11 - valve to prevent overfilling of the tank and valve to prevent fuel leakage when the vehicle rolls over; 12 - anti-pressure tube (degassing during filling); 13 - fuel pump with level sensor, assy
Pic. 2.216. The scheme of the fuel system: 1 - branch pipe for the pipeline going to the adsorber; 2 - ball valve to prevent overflow; 3 - anti-pressure tube when filling; 4 - restrictive valve; 5 - safety valve of excess pressure-vacuum; 6 - hole for air release during refueling; 7 – cavity for fuel expansion; 8 - filling hole; 9 - useful volume of fuel; 10 - valve to prevent overfilling of the tank and valve to prevent fuel leakage when the vehicle rolls over
Purpose of valves and filler neck
Overpressure-vacuum safety valve
In case of shutdown of the gasoline vapor recirculation circuit, this valve avoids the creation of excess pressure in the tank (tank swelling) or rarefaction (due to fuel consumption, the tank is crushed).
Restrictor valve
This valve prevents the tip of the leaded gasoline or diesel fuel nozzle from being inserted into the filler neck.
Overfill prevention valve and rollover prevention valve.
The operating element of the overflow prevention valve is a ball.
When the car is stationary during refueling, the ball rests on the saddle, thereby blocking a certain amount of air in the tank.
When the car moves, the ball moves away from the saddle, opening a message between the tank and the adsorber.
There must be a certain amount of air in the fuel-filled tank. This allows the fuel to expand without causing the tank to bulge.
The rollover prevention valve prevents the tank from emptying through the channel leading to the adsorber.
Filler neck
The filler neck for unleaded petrol has:
- smaller filler hole than a conventional filling nozzle (restrictive valve). The use of leaded gasoline leads to damage to the exhaust gas toxicity reduction system - an oxygen sensor and a catalytic catalyst;
- a valve that closes the filling hole to prevent gasoline vapors from escaping or gasoline leaking out;
- sealed stopper.