The controller has the ability to evaluate the results of its calculations and commands, remember recent operating modes and act in accordance with them. the controller's "self-learning" is a continuous process that continues throughout the entire service life of the vehicle.
Fuel is supplied using 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 engine starting mode.
The controller switches on the injectors sequentially. Each of the injectors is switched on every 720° of crankshaft rotation. This method allows for more precise dosing of fuel between cylinders and a reduction in the level of toxicity of exhaust gases.
The amount of fuel supplied is determined by the state of the engine, i.e. its operating mode. These modes are provided by the controller and are described below.
When the engine crankshaft begins to rotate with the starter, the first pulse from the crankshaft position sensor causes a pulse from the controller to turn on all injectors at once, which allows the engine to start faster.
The initial injection of fuel occurs each time the engine is started. The injection pulse duration 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 switches on the electric fuel pump relay, which creates pressure in the fuel supply line to the fuel rail.
The controller checks the signal from the coolant temperature sensor (coolant temperature sensor) and determines the amount of fuel and air required for starting.
When the engine crankshaft starts to turn, the controller generates a phased pulse to turn on the injectors, the duration of which depends on the coolant temperature sensor signals (coolant temperature sensor). On a cold engine the pulse duration is longer (to increase the amount of fuel supplied), and when warmed up - less.
Enrichment mode during acceleration.The controller monitors sudden changes in the throttle position (according to the TPS signal(throttle position sensor)), as well as for the MAF signal (mass air flow sensor) and provides the supply of additional fuel by increasing the duration of the injection pulse. The enrichment mode during acceleration is used only for fuel control in transient conditions (when moving the throttle valve).
Fuel Shut-Off Mode when braking with the engine. During engine braking with the gear and clutch engaged, the controller can completely disable fuel injection pulses for short periods of time. The fuel supply is switched on and off in this mode when certain conditions are created for the coolant temperature, crankshaft speed, vehicle speed and throttle opening angle.
Supply voltage compensation. When the supply voltage drops, the ignition system may produce a weak spark, and the mechanical movement of "opening" the injector may take longer. The controller compensates for this by increasing the energy accumulation time in the ignition coils and the injection pulse duration.
Accordingly, when the battery voltage increases (or voltage in the vehicle's on-board network) the controller reduces the energy accumulation time in the ignition coils and the injection duration.
Fuel shut-off mode. When the ignition is off, the fuel is not supplied by the injector, which prevents the mixture from spontaneously igniting in an overheated engine. In addition, fuel injection pulses are not supplied if the controller does not receive reference pulses from the crankshaft position sensor, i.e. this means that the engine is not running.
The fuel supply is also cut off when the maximum permissible engine crankshaft speed of 6200 rpm is exceeded, to protect the engine from operating at unacceptably high speeds.