The electronic system of injection of fuel (EFI — Electronic Fuel Injection) consists of three subsystems:
– systems of air supply in engine cylinders;
– systems of electronic control;
– fuel system.
Basic element of system is the control unit of the engine (PCM) which on the basis of information from many sensors operates fuel nozzles, changing the impulse length, i.e. an interval of time when nozzles are open. It provides preparation of the fuel-air mix corresponding to the required operational power setting.
The system of air supply in cylinders of the engine consists of the air filter, branch pipes, throttle knot, the control system of the mode of idling and an inlet collector. On models till 2001 of release the inlet collector and the distributive camera of the given air represent one knot.
On models since 2001 of release specially developed inlet collector with adjustment of capacity is established.
The throttle knot represents a pipe with adjustment of a stream of the air passing through it and serves only to operate amount of the air given to engine cylinders.
The lower part of throttle knot is warmed up by cooling liquid to exclude its frosting in winter time.
The adjusting screw is located in the top part of throttle knot. The sensor of provision of a butterfly valve is connected to an axis of a butterfly valve.
During the operation of the engine at a frequency of rotation of idling of a ratio of air and fuel it is regulated by a control system which consists of the control unit of the engine (PCM), the valve of a control system of the frequency of rotation of idling (IAC) and other sensors (ECT, IAT, TPS, MAP, MAF) working together with electronic system of injection of fuel (EFI). The valve of a control system of the frequency of rotation of idling (IAC) becomes more active depending on operating conditions of the engine (turning on of the air conditioning system, operation of the amplifier of steering, temperature of external air). This valve regulates amount of the air given to engine cylinders bypassing a butterfly valve. Thanks to it, at warming up of the engine, even at the closed butterfly valve, air comes to engine cylinders, regulating idling rotation frequency. The inlet collector also reduces pulsations of an air stream.
The system of electronic control operates fuel injection, an ignition advancing, diagnostic system and other systems.
The fuel system consists of the following components:
– fuel pump;
– fuel pressure regulator;
– fuel filter;
– fuel-supply lines;
– distributive fuel highway;
On models till 2001 2 fuel filters are installed: the main — on the left side of a motor compartment, and additional — in the block of the fuel pump / fuel level sensor.
On models since 2001 1 fuel filter is installed in the block of the fuel pump / fuel level sensor.
Nozzles dose and spray fuel. When giving tension the needle rises by a solenoid winding, passing fuel. The amount of fuel is defined by duration of an impulse during which the nozzle is open.
The main relay of the fuel pump is located in the block of relays/safety locks in a motor compartment and is operated on two electric chains. On the first chain control is exercised from the control unit of the engine (PCM), and on the second — from the ignition lock. If after inclusion of ignition start of the engine is not carried out, the PCM block will switch-off the relay of the fuel pump through 2 pages. Further, at start of the engine, after the first impulse from the sensor of position of the camshaft of the relay turns on the fuel pump.