Engine air/fuel ratio control responsive to stereo ego sensors

An air/fuel control method for an engine having first and second engine banks each communicating with a respective first and second exhaust gas oxygen sensor, comprising the steps of:

• deriving a feedback signal from an average of output signals from the first and second sensors;
• generating a first modified feedback signal by adding an adjustment signal derived from a difference between said output signals from the first and second sensors to said feedback signal;
• generating a second modified feedback signal by subtracting said adjustment signal from said feedback signal;and
• trimming fuel delivered to the first bank in response to said first modified feedback signal and trimming fuel delivered to the second bank in response to said second modified feedback signal.

An air/fuel control system for an engine having first and second engine banks, comprising:

• first and second exhaust gas oxygen sensors each communicating with the first and second engine banks and each having first and second output signals, respectively;
• feedback means for deriving a first feedback signal by averaging said first and second output from the first and second sensors to generate an average signal and integrating said average signal to generate said first feedback signal;
• difference means for providing an adjustment signal by integrating a difference between said first and second output signals;
• a controller adding said adjustment signal to said first feedback signal to generate a first modified feedback signal and subtracting said adjustment signal from said first feedback signal to generate a second modified feedback signal;
• and
• trimming means for trimming fuel delivered to the first bank in response to said first modified feedback signal and trimming fuel delivered to the second bank in response to said second modified feedback signal.