General information
The power system consists of a fuel tank, an electric fuel pump placed in it, an EFI main relay, injectors, a fuel pressure regulator, an air cleaner assembly and a throttle body. All models are equipped with an electronic fuel injection system. All power/emission control systems controlled by a second-generation on-board self-diagnosis system (OBD-II), equipped with an air mass measurement sensor (MAF), replacing the previously used paddle-type airflow meter (see chapter Engine management and emission control systems).
Electronic fuel injection system (EFI)
In the system under consideration, to control the injection of fuel through injectors directly into the intake port of each of the combustion chambers of the engine, electrical impulses of a clearly limited duration are used. The moment and duration of the opening time of each of the injectors is controlled by the electronic control module (ECM) systems. The ECM continuously monitors various engine operating parameters and, based on the analysis of incoming information, determines the required amount of fuel injected into each of the intake ports. In parallel, the ECM also controls the ignition timing. The throttle body serves solely to control the air supply to the air supply system. Due to the fact that each of the cylinders is equipped with its own injector located in the immediate vicinity of the intake valve, this scheme allows for very precise control of the composition of the air-fuel mixture.
The fuel pressure regulator maintains a constant pressure difference between the inlet and outlet sections of each of the injectors. The nominal value of the working pressure is 2.9 kgf / cm2. The regulator is equipped with a check valve, a diaphragm type sensing element and a loaded spring. The pressure drop is controlled by throttling the fuel in the gap between the shut-off valve and its seat. Excess fuel is returned to the fuel tank through the return line.
The fuel pressure pulsation damper serves to eliminate the wave formation that occurs in the fuel lines at the moments of opening and closing of the injectors. The damper is equipped with air and fuel chambers separated by a membrane, which actually damps elastic vibrations in the fuel flow.
The amount of air supplied to the engine is determined by the position of the throttle valve and the speed of the crankshaft. An intake air flow sensor provides the control module with information from which the ECM determines how long the injectors need to open.
Fuel pump and fuel lines
The supply of fuel from the gas tank to the injection system and the return of its excess back to the gas tank is carried out through two metal lines laid under the bottom of the car. The rotary type submersible electric fuel pump is located inside the gas tank and is integrated into a single assembly with the fuel flow sensor unit. A fuel filter is provided at the outlet of the gasoline pump, which provides filtering of particles up to 20 - 30 microns in size.
The fuel vapor return system carries out the removal of fuel vapors back to the gas tank through a separate return line.
The fuel pump continues to function during the entire time the engine is running, i.e., while the ECM receives reference pulses from the electronic ignition system (see chapter Engine electrical equipment). 2–3 seconds after the reference pulses are stopped, the pump stops.
Exhaust system
The exhaust system consists of downpipes equipped with an oxygen sensor, catalytic converters, and a silencer.
The catalytic converter is the main component of the emission control system. The monoblock transmitter can be used in combination with a three-function reducing (see Chapter Engine management and emission control systems).