Fig. 2.47. EFI system diagram (Electronic fuel injection system)
The electronically controlled fuel injection system type L (Fig. 2.47) directly determines the mass of air at the intake using a hot-wire air flow sensor. An independent injection system is used (in which fuel is injected into each cylinder once for every two revolutions of the crankshaft). In addition, group injection is used when starting the engine (fuel is injected once into two cylinders for each revolution of the crankshaft). There are two modes of operation of the fuel injection system:
- a) synchronous injection, in which the basic injection duration is adjusted according to sensor signals so that fuel injection always occurs at a certain crankshaft position;
- b) asynchronous injection, in which fuel injection is performed upon detection of requests from sensor signals, regardless of the crankshaft rotation angle.
In addition, to protect the engine and improve fuel economy, the system performs fuel cut-off, which temporarily stops fuel injection in accordance with driving conditions.