Operating principle
Fuel under pressure is supplied to four injectors installed directly in front of the intake valves. The amount of fuel injected depends only on the duration of the open solenoid valve of the injector. The duration of the open solenoid valves of the injectors is determined by the electronic control unit depending on the engine speed, cooling temperature, angular position of the throttle valve and the amount of incoming air. On engines with a turbocharger, an additional correction for the boost pressure of the air is taken into account.
Fuel supply
The electric fuel pump takes fuel from the tank and pumps it through a fine filter under 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 constant injection pressure and drains excess fuel into the tank, i.e. it ensures fuel circulation in the system and eliminates the formation of fuel vapors in it. On engines with a turbocharger, the fuel supply pressure is regulated depending on the air pressure in the intake manifold.
The electronic control unit receives signals from sensors, and the main parameters determining the fuel dosage 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 incoming signals and generates pulses of fuel supply time to the electromagnetic valves of the injectors.
Idling
The additional air supply valve, installed in the air channel made parallel to the throttle valve, supplies the engine with the minimum amount of air necessary for its smooth operation at idle. On vehicle modifications with air conditioning and/or power steering, special electromagnetic valves provide additional air supply to the engine when the air conditioning is turned on and compensation when the power steering is operating.
Acceleration
When the throttle valve is opened sharply, its position sensor determines the speed of its movement and sends a corresponding electrical signal to the electronic control unit, which commands the duration of the injector opening to increase, thereby ensuring the necessary enrichment of the combustible mixture.
Cold engine starting
During cold starting and warming up of the engine, the additional 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, consequently, the crankshaft speed at idle decreases as the engine warms up.
Information about the coolant temperature from the sensor is sent to the electronic control unit, which, based on this information, regulates the duration of fuel injection, ensuring the necessary enrichment of the mixture at start-up and during the initial period of engine operation.