DUAL EGO SENSOR CLOSED LOOP FUEL CONTROL

Air/fuel ratio control for an internal combustion engine includes the use of a first exhaust gas oxygen sensor (EGO) upstream of a catalytic converter and a second exhaust gas oxygen sensor downstream of the catalytic converter. The output of the first EGO sensor is passed through a high pass filter and then combined in a summer with the output of the second EGO sensor. The output of the summer is applied to a proportional and integral controller which then provides an output used to generate the fuel control signal.