Pinging control

At idle speed the control unit sets the “closed” phase:
- cam in normal position
- intake box short manifolds.
In the other engine operating conditions, the control unit chooses the most suitable configuration to optimise performance - consumption - emissions. During deceleration the box intake ducts are al-ways “short”.

Pinging control

The control unit detects the presence of pinging by processing the signal leading from the corresponding sensor. The control unit continuously compares he signals from the sensor with a threshold value, which is in turn continuously updated, to take account of the engine background noise and engine ageing.
This way the control unit is able to detect the presence of pinging, (or incipient pinging) and reduces the spark advance (in steps of 3° up to a maximum of 6°) until pinging ceases.
The advance is then gradually restored to the base value (in 0.8° steps).
During acceleration, a higher threshold is used to take account of the higher engine noise in this condition.
The pinging control logic also has a self-adapting function which any continuously repeated advance reductions in order to adapt the map to the different engine conditions.

Enrichment control during acceleration

If during the request for acceleration the change in the air flow meter signal exceeds a pre-defined threshold, the control unit increases injection (injection time) to rapidly reach the required engine speed.
Recovery:
- the control unit replaces the signal leading from the faulty air flow meter with the throttle potentiometer signal.