Adaptive compensation of fuel dynamics in an SI engine using a switching EGO sensor

Current engine controllers employ a feedforward compensator to eliminate the effects of fuel dynamics (“wall-wetting”) on the air-fuel ratio trace. Uncompensated or improperly compensated fuel dynamics may cause significant A/F excursions during transient operations, accompanied by increased emissions levels. This paper describes the development of an adaptive algorithm for transient fuel compensation using only a switching exhaust gas oxygen (EGO) sensor, in order to ensure proper compensation of fuel dynamics in spite of initial miscalibrations, vehicle-to-vehicle variability, changing dynamics due to aging (intake valve deposits build up), or changing dynamics due to changing fuel properties. Experimental results demonstrate the effectiveness of the proposed algorithm