The operation of the injection system closely intersects with the operation of the emission control system, more detailed information on which can be gleaned from the materials of the Chapter Engine management.
Air supply system
The system consists of an air cleaner, air hoses, throttle body, idle speed stabilizer and intake manifold. The intake manifold of both 4-cylinder and V6 engines consists of two sections: the lower (the pipeline itself) and top (injection chamber). The procedures for removing and installing both sections are described in Chapter Engine.
The throttle body has a single-chamber cross-flow design. The lower part of the throttle body is heated by engine coolant to prevent icing in freezing weather. The idle speed adjustment screw is located on top of the throttle body. Throttle position sensor (TPS) connected to the axis of the latter and monitors the degree of its opening.
At idle speed of the engine, the composition of the air-fuel mixture is controlled by the idle speed stabilization system (IAC), which includes PCM, an electronic coolant temperature sensor (EATING), IAC valve and a set of information sensors (intake air temperature sensor [IAT], throttle position sensor [TPS], manifold absolute pressure sensor [MAP], etc.), - see also Chapter Engine management. The operation of the IAC valve is controlled by the PCM, based on information about the current load on the engine (functioning of A/C, power steering, coolant temperature, etc.). The valve regulates the flow rate of air entering the intake pipeline through the throttle body. When developing commands for actuating the IAC valve, the PCM relies on data from various information sensors and allows you to determine the current vehicle speed, coolant temperature, A/C status (on/off), use of power steering, etc. To prevent idle stability during engine start-up, the IAC valve opens during cranking immediately after starting to allow more air to enter the intake manifold.
Electronic control system
The composition and principle of operation of the electronic control system and PCM are discussed in detail in Chapter Engine management.
Fuel supply system
Fuel system components include: electric fuel pump, fuel pressure regulator, injection injectors, fuel pulsation damper, injection injectors, fuel line and main power system relay.
The electric fuel pump is located inside the gas tank. The pump draws fuel from the tank through the filter element, then pumps it through an additional fuel filter and delivers it to the injection injectors. A safety valve is also provided to prevent an excessive increase in fuel pressure in the event of a tract obstruction.
The fuel pressure regulator provides a constant pressure of fuel supply to the injectors. Excess fuel is sent back 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 its 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 and intake air). The necessary information is supplied to the module in the form of signals from various engine sensors.
The main injection system relay is mounted on the left or right in front of the windshield under the fairing panel and consists of two operating elements, one of which is the PCM and fuel injectors relay, and the second is the fuel pump relay.