Adaptive Control
Drifts and faults in the sensors and actuators of the fuel delivery system, as well as unmetered air leakage into the intake system influence the primary control. This causes deviations in the air to fuel ratio. The adaptive control determines the controller correction in two different ranges. See Fig 1 .
Lambda deviations in Range 1 are compensated by an additive correction value multiplied by an engine speed term. By this means an additive correction per time unit is derived.
Lambda deviations in Range 2 are compensated by a multiplicative factor.
Each value is determined only within its corresponding range. But each adaptive value corrects the primary control within the whole load and speed range of the engine. After the next start, the stored adaptive values are included in the calculation of the primary fuel control; just before closed-loop fuelling control is activated.