The pressure reducing valve keeps the pressure in the fuel system constant within the range of about 3.8-3.9 bar.
Fuel is supplied through electronically controlled valve injectors, i.e. intermittently injected into the camshaft just before the engine intake valves.
The engine control unit controls the operation of the injectors, providing sequential fuel injection. This means that the valve injectors fire in turn according to the ignition order. At the same time, the amount of injected fuel is controlled.
Air is drawn in by the engine through the air filter and through the throttle valve and intake manifold to the intake valves. The amount of incoming air is regulated by a throttle valve, the opening angle of which is performed by a stepper motor according to «team» control unit.
The volume of incoming air is taken into account by the mass air flow meter, which is built into the engine control unit. In the case of the air mass flow meter, a thin sensitive film is located as an incandescent element, which is cooled by the passing mass of intake air.
To keep the temperature of the film constant despite air cooling, the engine control unit regulates the filament current in accordance with the amount of (weight) incoming air.
If, for example, the film begins to cool due to an increase in the volume of incoming air, the applied voltage is immediately increased to maintain the film's filament temperature. By changing the filament current, the control unit determines the load on the engine and accordingly regulates the volume of injected fuel.
The electronic engine control unit is a small, fast-running computer. It determines the optimal ignition timing, fuel injection and the amount of fuel injected.
The information received by the electronic unit from sensors, as well as the commands given to the actuators or control mechanisms, ensure optimal engine operation in any situation that develops at the moment of movement.
If one or more of the main sensors fails, the control unit executes an emergency program to reduce the danger to the engine and ensure continued movement.
In such cases, the engine starts to work intermittently and when you press the accelerator pedal, it may stall.
Sensors and actuators of the fuel injection system
The crankshaft position sensor is located in the cylinder block next to the flywheel. This sensor transmits to the control unit information about the number of revolutions with which the crankshaft rotates, and also informs about the position of the piston of cylinder No. 1 at TDC.
The camshaft position sensor is located on the end side of the cylinder head cover. Together with the crankshaft position sensor, it transmits to the control unit information about the presence of the piston of cylinder No. 1 at TDC, which serves as the basis for synchronizing the ignition timing and fuel injection sequence.
The throttle actuator consists of an electric motor with two potentiometers. The electric motor controls the throttle position. This ensures that the idle speed remains constant regardless of the number of consumers connected to the on-board network, such as, for example, power steering or air conditioning compressor.
The throttle angle sensor/potentiometer is located directly on the damper actuator and provides the control unit with information about the current throttle opening angle. The second potentiometer is spare and duplicates information. In case of failure of the first potentiometer, it performs its function.
The accelerator pedal position sensor is located in the footwell on the driver's side. By means of a short pull, the sensor recognizes the position of the accelerator pedal and transmits information to the engine control unit in the form of a signal with a varying voltage. For safety reasons, the sensor duplicates the transmitted signal.
The coolant temperature sensor, located in the thermostat housing, is a negative temperature coefficient resistor. This means that the resistance of the sensor decreases as the temperature of the coolant increases. The intake air temperature sensor is also a resistance (resistor) with a negative temperature coefficient and is part of the engine control unit.
The fuel tank is ventilated by means of a container with activated carbon and a solenoid valve, also called a regeneration valve. Activated carbon absorbs fuel vapors that form in the tank as a result of fuel heating. When the engine is running, the fuel absorbed by the coal is released and it enters the engine for combustion.
lambda probe (oxygen sensor) designed to control the operation of the catalyst, determining the oxygen content in the OT and transmitting the relevant information to the control unit.
The knock sensor is located on the cylinder block near the guide rod oil level indicator and serves to prevent knocking fuel combustion, maintaining the optimum ignition timing. Thus, the energy resulting from the combustion of fuel is better used, and fuel consumption is reduced.
As part of the maintenance of the car, there is no need to adjust the idle speed, ignition timing and CO content in the exhaust gases. These indicators are maintained unchanged by electronics.
If the performance begins to differ greatly from the nominal, then the reason for this is a defect in the parts that must be replaced. Checking the fuel injection system is only possible using the appropriate diagnostic equipment.
Visual inspection of the fuel injection system
Troubleshooting in the fuel injection system or the elimination of possible malfunctions require the use of special instrumentation. Such devices are very expensive and, as a rule, are available only in specialized workshops.
The car owner can only perform visual inspection and inspection of the elements of the injection system on his own.
1. Check the battery, see relevant chapter.
2. Check all fuses, see relevant chapter.
3. Disconnect and then reinstall all plugs or sockets in the relevant system. Make sure that the fit and fastening of plug connections and wires in the engine compartment is in order.
4. Look at all points «masses» (-) and check that the wires are not loose or the contacts are rusty.
5. Inspect all hoses and lines to make sure they are tight, not cracked or broken, and hose rubber has not become porous. Tighten loose fittings of hoses and pipelines.