The controller has the ability to evaluate the results of its calculations and commands, remember the modes of recent operation and act in accordance with them. «self-learning» controller is a continuous process that continues throughout the life of the vehicle.
Fuel is supplied by one of two different methods: synchronous, i.e. at a certain position of the crankshaft, or asynchronous, i.e. independently or without synchronization with the rotation of the crankshaft. Synchronous fuel injection is the most commonly used method. Asynchronous fuel injection is used mainly in the engine start mode.
The controller turns on the injectors in series. Each of the nozzles is activated every 720°of crankshaft rotation. This method allows you to more accurately dose the fuel into the cylinders and reduce the level of toxicity of exhaust gases.
The amount of fuel supplied is determined by the state of the engine, i.e. its mode of operation. These modes are provided by the controller and are described below.
When the engine crankshaft starts to be rotated by the starter, the first pulse from the crankshaft position sensor causes a pulse from the controller to turn on all the injectors at once, which makes it possible to accelerate the engine start.
Initial fuel injection occurs each time the engine is started. The duration of the injection pulse depends on the temperature. On a cold engine, the injection pulse increases to increase the amount of fuel; on a warm engine, the pulse duration decreases. After the initial injection, the controller switches to the appropriate injector control mode.
Engine start mode. When the ignition is turned on, the controller turns on the electric fuel pump relay, which creates pressure in the fuel supply line to the fuel rail.
The controller checks the signal from DTOZH (coolant temperature sensor) and determines the amount of fuel and air required for starting.
When the engine crankshaft starts to rotate, the controller generates a phased pulse to turn on the injectors, the duration of which depends on the DTOZH signals (coolant temperature sensor). On a cold engine, the pulse duration is longer (to increase the amount of fuel supplied), and on warm - less.
Enrichment mode when accelerating. The controller monitors abrupt changes in throttle position (on signal TPS (throttle position sensor)), as well as behind the DMRV signal (mass air flow sensor) and provides an additional amount of fuel by increasing the duration of the injection pulse. Acceleration rich mode is only used for transient fuel control (when moving the throttle).
Fuel cut mode during engine braking. When braking the engine with the gear and clutch engaged, the controller may completely disable the fuel injection pulses for short periods of time. Turning off and on the fuel supply in this mode occurs when certain conditions are created for the coolant temperature, crankshaft speed, vehicle speed and throttle opening angle.
Supply voltage compensation. If the supply voltage drops, the ignition system may produce a weak spark, and mechanical movement «discoveries» injectors may take longer. The controller compensates for this by increasing the energy storage time in the ignition coils and the duration of the injection pulse.
Accordingly, with increasing battery voltage (or voltage in the vehicle's on-board network) the controller reduces the time of accumulation of energy in the ignition coils and the duration of injection.
Fuel cut off mode. When the ignition is off, the nozzle does not supply fuel, as a result of which the spontaneous ignition of the mixture in an overheated engine is excluded. In addition, fuel injection pulses are not applied if the controller does not receive reference pulses from the crankshaft position sensor, i.e. this means the engine is not running.
The fuel supply is also cut off when the maximum permissible engine speed of 6200 min is exceeded to protect the engine from operating at unacceptably high speeds.