Steady state fueling compensation for purge control in internal combustion engines

Presented is a feed-forward controller that reduces air-fuel (A/F) ratio excursions during a canister purge event. The controller is linear parameter-varying (LPV) model and estimates the necessary changes in the fuel pulse-width (FPW) based on a hydrocarbon (HC) sensor located in the purge line. Coordination between the purge fuel vapor arrival to the intake manifold and the fueling command is realized using a transport delay model. The proposed controller is experimentally validated. A significant reduction in A/F excursions is achieved during the steady state engine operating conditions associated with highway conditions.