Starting and post-starting

Starting and post-starting

During starting it is not possible to recognize the engine timing and consequently it is not possible to implement the timed injection.

During the first revolutions of the engine an initial simultaneous injection is carried out (also because the considerable fluctuations in the rotation speed do not allow the correct calculation of the injection timing) and subsenquently the injection is the timed type.

The "basic" injection time "is increased by a multiplication coefficient for the entire time the engine is driven by the starter motor.

After starting has taken place the coefficient is gradually reduced until is disappears within a given time which the lower the engine temperature the longer the time taken.

k: enrichment coefficient
t : time
α: decrease depending on the engine temperature
ON : engine driven (crank)
OFF : engine started (run)

Operation when cold

In these conditions there is a natural weakening of the mixture as a result of the reduced evaporation and the strong condensation of the fuel on the inner walls of the inlet manifold: in addition, the increased viscosity of the lubrication oil causes an increase in the passive resistance of the engine.

The "basic" injection time is corrected by a multiplication coefficient which depends on the temperature and the speed of the engine.

Operation in full load conditions

The strategy is enabled when the butterfly opening exceeds 70°.

The "basic" injection time is multiplied by a coefficient (dependent on the engine speed) equal to around 1.1.