Electronic Fuel Injection (EFI) System — General Information

All vehicles covered in this manual are equipped with an electronic multiport fuel injection system (EFI). Injection is carried out sequentially into the intake ports of each of the combustion chambers in the order of ignition and in an amount determined by the current needs of the engine. There is one injection injector for each of the engine cylinders. The injectors are mounted on the intake manifold assembly, the upper section of which is a pressure chamber, providing optimal conditions for air supply to the intake tract and its dosage by a removable throttle chamber (throttle body).

main component (think tank) injection system is an on-board processor, also called the powertrain control module (RSM). The PCM analyzes the data continuously received by it from various information sensors and calculates the currently optimal composition of the air-fuel mixture. The system also provides automatic compensation for changes in such external factors as the height of the vehicle above sea level, load and engine speed.

Fuel supply to the system path is provided by a high-pressure submersible electric fuel pump. By pumping through the fuel filter, the fuel enters the fuel line of the EFI system through the gas pipeline system.

The fuel line assembly includes electric injectors that perform metered injection of fuel directly into the inlet ports of the engine combustion chambers. In addition to the injectors, the fuel line assembly also includes a fuel pressure regulator that constantly maintains the fuel pressure at a given level. Excess fuel entering the line is returned to the fuel tank through the return line.

The injectors are permanent solenoid valves. The main components of an injector are: a control solenoid, a plunger and a needle valve. All of the listed parts are placed in a common housing. When an electric current passes through the solenoid coil, the needle valve opens slightly, fuel under pressure fills the cavity of the injector body and is ejected through the nozzle into the combustion chamber of the corresponding cylinder. The amount of injected fuel is determined by the duration of the valve opening time, i.e., the duration of the voltage supply to the electromagnet coil. In order to limit the strength of the current passed through the injectors, resistors are included in the wiring of the circuits of the latter.

The duration of the injectors is controlled by the PCM. The module memory contains the basic values of the valve opening time for various combinations of input parameters (engine speed, intake air quantity and temperature). The necessary information is sent to the module in the form of signals from the corresponding engine sensors.