Description & Operation: Compensation: Knocking

Fig 1: Engine Knocking - Function Diagram

Courtesy of SAAB-SCANIA OF AMERICA, INC.

If the engine is knocking, it is corrected by retarding the ignition for the cylinder in question. If knocking persists despite the retardation, the correction factor will be increased. Closed loop will then be deactivated (if it was active) as it would otherwise counter-compensate.

Fig 2: Correction Factor Graph

Courtesy of SAAB-SCANIA OF AMERICA, INC.