Operating principle
Pressurized fuel is supplied to four injectors located directly in front of the intake valves. The amount of injected fuel depends only on the duration of the open injector solenoid valve. The duration of the open solenoid valves of the injectors is determined by the electronic control unit depending on the engine speed, cooling temperature, throttle angle and the amount of incoming air. On engines with a turbocharger, a correction for air boost pressure is additionally taken into account.
Fuel supply
An electric fuel pump draws fuel from the tank and pumps it through a fine filter at a pressure of approximately 5 kg/cm2 into the distribution line and injectors. The fuel pressure regulator installed at the end of the distribution line maintains a constant injection pressure and drains excess fuel into the tank, i.e. it circulates the fuel in the system and eliminates the formation of fuel vapors in it. On engines with a turbocharger, the fuel supply pressure is controlled depending on the air pressure in the intake manifold.
The electronic control unit receives signals from sensors, and the main parameters that determine the dosage of fuel are signals about the angular position of the throttle valve and the amount of air entering the cylinders. On engines with a turbocharger, after it is turned on, the electronic control unit processes information from the fuel pressure sensor.
The electronic unit processes the incoming signals and generates fuel supply time pulses to the solenoid valves of the injectors.
Idling
The auxiliary air supply valve, installed in the air duct, made parallel to the throttle valve, supplies the minimum necessary amount of air to the engine for its smooth operation at idle. On vehicle modifications with air conditioning and / or power steering, special solenoid valves provide additional air to the engine when the air conditioner is turned on and compensation when the power steering is running.
Overclocking
When the throttle valve is suddenly opened, its position sensor determines the speed of its movement and issues an appropriate electrical signal to the electronic control unit, at the commands of which the injector opening time increases and thereby the necessary enrichment of the combustible mixture is ensured.
Starting a cold engine
During a cold start and warming up of the engine, the auxiliary air supply valve supplies additional air to the engine, which leads to an increase in the crankshaft speed. The valve is heated by liquid from the cooling system and its flow area and, therefore, the idle speed decreases as the engine warms up.
Information about the temperature of the coolant from the sensor enters the electronic control unit, which, on its basis, regulates the duration of fuel injection, providing the necessary enrichment of the mixture at start-up and during the initial period of engine operation.