Fuel Injection

Fuel Injection
The ECM controls one injector per cylinder in sequential operation. The size of the injector used is so that stoichiometric control is possible at minimum load with allowance for purge valve correction, and also at maximum load to provide sufficient fuel-flow at all engine speeds. The timing of injector firing relative to intake valve closing, during normal starting and running conditions is optimized to provide the best compromise between emissions and performance, time to first ignition and smooth engine operation at start-up, for all engine conditions at all temperatures. The mass of fuel per-injection is derived from a calculation based on a ratiometric match to the metered airflow.

The ECM is capable of adapting to fuel system tolerances and engine internal wear under all operating conditions. The ECM continually monitors the differential pressure between the fuel rail and plenum, and uses this value to calculate the injector pulse width with the required mass of fuel per-injection. The ECM also continually monitors the temperature of the fuel being injected into the engine and provides compensation for the changing flow characteristics of the fuel system at different temperatures. By monitoring the battery supply voltage the ECM can ensure that the fuel supply to the engine is unaffected by voltage fluctuation.