Power system diagram
1 - Fuel tank
2 - Fuel electric pump
3 — Clip of fastening of the fuel pump
4 - Suction jet pump
5 - Pressure limiting valve
6 - Drain safety valve
7 — the Refueling ventilating pipeline
8 - Back damper
9 — a tube of a jellied mouth
10 - Filler cap
11 - Equalizing pipeline of the fuel tank
12, 13 - Working ventilation ducts
14 - Tank
15 - Shutter valve
16 - Vapor outlet tube
17 - Return fuel line
18 - Fuel supply line
19 - Fuel filter
20 - Pressure regulator
21 - Two-position three-line valve
22 - Distribution line
23 — Outside air supply pipeline
24 - Engine control unit
25 - EVAP valve
26 - Suction pipeline
27 - Carbon absorber
The fuel pump is installed in a special holder on the right side of the fuel tank, which ensures uninterrupted fuel supply to the pump in all modes and operating conditions of the vehicle. Fuel is supplied to the holder by a suction jet pump installed in the holder of the holder. A suction jet pump built into the fuel tank equalizer pipe delivers fuel to the yoke from the left side of the fuel tank. Both jet pumps are driven by a fuel return line and the required pressure to operate the suction jet pumps is controlled by a pressure limiting valve. The fuel return line is protected by a special valve that closes if the pressure drops when the fuel return line is damaged or disconnected. This prevents fuel from leaking out of the fuel tank, for example, when the vehicle is turned over or tilted.
The check flap prevents fuel from sloshing back into the filler neck after the fuel nozzle is turned off.
On petrol models The fuel is supplied by the fuel e/pump through the fuel supply line and the fuel filter to the distribution line. On models with engine M52TU fuel is fed back to the fuel tank through a pressure regulator fixed to the distribution line and a fuel return line. On models with engine M73 return of fuel to the fuel tank is carried out through a two-position three-line valve, a pressure regulator and a return fuel line. This rail return engine fuel circuit is turned on to start the engine and stays on for less than 1 minute. After this phase, the two-position three-way valve closes the fuel return line from the distribution line. At the same time, with the help of the same valve, a pipeline branch to the pressure regulator directly on the fuel filter is activated. Fuel cannot return from the distribution line. On models with engine M62TU The pressure regulator and fuel filter are combined into one unit, the distribution line has no shut-off valves, and fuel flows directly from the fuel filter/pressure regulator assembly back into the fuel tank.
On diesel models, the electric fuel pump supplies the engine with fuel from the fuel tank. Two types of high pressure pumps are used for injection into cylinders (injection pump): distribution injection pump (delivers fuel directly to the injector of each cylinder) and injection pump for the Common Rail system (creates the necessary pressure in the distribution line for all injectors). In Common Rail systems, another pump is installed between the injection pump and the electric fuel pump - the main pump (M57) or gear (M67), - which, with high fuel consumption, maintains the operation of the fuel pump in the fuel tank.
The fuel level is measured in each part of the fuel tank using a lever gauge. The right sensor is built into the fuel supply unit; the left sensor is in the left sensor assembly. Taking into account the obtained values of the electrical resistances of the left and right lever sensors gives the actual filling level of the fuel tank.
Driving style has a significant impact on fuel consumption. Below are some tips for saving gasoline.
- After starting the engine, immediately move off, even if this happens in the cold;
- When stopping the car for longer than 40 seconds, turn off the engine;
- Always drive in the highest possible high gear;
- When driving long distances, maintain a steady speed whenever possible. Avoid driving at high speeds. Do not slow down unnecessarily;
- Do not transport excess cargo by car;
- Check tire pressure. Avoid excessive pressure reduction.
Safety and cleanliness measures when working with the fuel system
- Do not work on the fuel system near an open flame, do not smoke and do not turn on heaters! Keep a fire extinguisher ready;
- Always disconnect the negative cable from the battery before working on the fuel system to prevent sparks. Before disconnecting the battery, read the trouble codes (see chapter Engine Electrical Systems);
- Keep the workplace well ventilated - fuel vapors are poisonous;
- Do not allow gasoline to come into contact with rubber or leather surfaces, as however, they may be damaged;
- The fuel system is pressurized and fuel may escape when it is opened - wear protective goggles. Clean up spilled fuel with rags;
- Hose connections are fastened with tape or clamp clamps. Clamping clamps during disassembly should be replaced with tape ones;
- Connections and places adjacent to them must be thoroughly cleaned before opening;
- Place the removed components on a clean pad and cover with polyethylene, paper or lint-free rags;
- Close open male connectors, for example with suitable plugs;
- Install only clean parts - remove replacement components from the packaging immediately before installation. Do not use parts that have been stored unpackaged;
- Avoid using compressed air with an open fuel system, if possible, try not to move the car;
- Do not use sealants containing silicone, as silicone particles that have entered the engine do not burn out and may cause failure of the lambda probes;
- Before removing the fuel tank, pump out the fuel from it with a pump specially designed for this purpose;
- Remember that even an empty fuel tank remains explosive;
- After installing the fuel system components, start the engine and check all connections for leaks.