Patent Number: 6,253,542

Title: Air-fuel ratio feedback control

Abstract: A method of controlling the air-fuel ratio of an internal combustion engine having an exhaust passage including a catalytic converter. The method includes providing a first air-fuel ratio sensor upstream of the catalytic converter, and providing a second air-fuel ratio sensor downstream of the catalytic converter. A control module having an input connected to the first and second air-fuel ratio sensors and an output connected to actuators for controlling the engine is also provided. This establishes a first feedback loop including the first air-fuel ratio sensor and a second feedback loop including the second air-fuel ratio sensor. The method further includes detecting an output value of the second air-fuel ratio indicative of a rich or lean exhaust gas air-fuel ratio. In response to the output value, the system monitors the engine mass airflow, and controls the duration of air-fuel ratio of the engine as a function of the engine mass airflow.

Inventors: Omara; Ahmed Abdelaziz (Ann Arbor, MI), Hamburg; Douglas Ray (Bloomfield Hills, MI), Bradley; John Edward (Dearborn, MI)

Assignee: Ford Global Technologies, Inc.

International Classification: F02D 41/14 (20060101); F01N 003/00 ()

Expiration Date: 07/03/2018