Knock control

Knock control

The ECU can delay ignition selectively on each cylinder as required according to the combination of values received from the knock and phase sensors. It:

• reduces spark advance by 3° steps to reach a maximum of 9°
• updates the threshold considering:
  • basic noise
  • engine ageing.

During acceleration, the ECU employs a higher threshold to adapt to increased engine noise. When knock disappears, the ECU decreases spark advance in 0.75° steps to complete recovery.

The self-adapting feature of the ECU:

• stores the continuous, repeated spark advance reductions
• updates the map to the various conditions in which the engine is working.

Recovery:

• in the event of failures to either the phase sensor, the knock sensor or the injection ECU, a spark delay - which is variable according to the rpm and the engine temperature - is implemented. Maximum spark delay is always lower than 9° engine.

Fuel cut-off upon accelerator pedal release

In the following conditions:

• acknowledge idling ratio
• rpm exceeding a certain threshold

the ECU deactivates injection according to:

• rpm
• engine temperature
• vehicle speed.

Before reaching idling speed, the rpm decrease dynamics is checked. If this is higher than a certain value, fuel injection is partially reactivated according to a logic to take the engine to idling speed smoothly. Once idling conditions are reached, the normal functions are reactivated. Fuel cut off is active only 20 seconds after engine start-up.

Acceleration enrichment control

Upon considerable demand for acceleration, the ECU adjusts the injection time and the throttle position.

Recovery

• - the ECU replaces the signal from the faulty air flow meter with the signal from the potentiometer built-into the throttle and DVL.