John Bradle

US Patent:

6311680, Nov 6, 2001

Filed:

Mar 21, 2000

Appl. No.:

9/532842

Inventors:

John Bradle - Dearborn MI
Ahmed A. Omara - Ann Arbor MI
Douglas Ray Hamburg - Bloomfield Hills MI

Assignee:

Ford Global Technologies, Inc. - Dearborn MI

International Classification:

F02D 4106

US Classification:

123672

Abstract:

An engine control system includes an adaptive bias sub-system (100) that generates bias values for controlling the air-fuel ratio. The sub-system (100) includes an integral controller (118) that reads an error signal from a post-catalyst switching EGO sensor (112). A plurality of noise isolation integrators (122) filter any noise resulting from a particular engine operating condition (e. g. acceleration, deceleration, idling) from the integrated error signal and stores the signal in a corresponding keep-alive memory (124) as a bias value for that engine operating condition. In a preferred embodiment, the post-catalyst feedback loop includes a gated proportional controller 116 that turns on for a limited period of time after the post-catalyst switching EGO sensor (112) switches states. By generating active adaptive bias values based on the engine's actual performance rather than relying on static, empirically-derived bias values, the active adaptive bias sub-system (100) can continuously optimize the stored bias values as the engine and engine controller ages or if the engine control system is placed in a different vehicle.