Patent ID: 7107143
Filing Date: 2006-09-12
Classification: F02D,Y02T

Abstract:
1. A method for repeatedly estimating intake manifold oxygen concentration during operation of a lean burn engine, the method comprising the steps of: (1) operating a state observer (SO) by combining determined air/fuel ratio (A/F) and mass air flow (MAF), and estimated cylinder mass flow (CMF) and exhaust gas recirculation flow (EGR) and calculating percent oxygen (O (2) if intake manifold pressure is sufficiently less than atmospheric pressure (atm) to indicate throttled operation, continually repeating step 1; if not, operating adaptive disturbance estimator (ADE); (3) if EGR/CMF is greater than a predetermined threshold value between 0 and 1, operating ADE to correct all disturbances and adjusting accordingly the values input to the SO, if not, then operating ADE to correct only MAF values and continually repeating steps 1–3.