Emission control system for internal combustion engines utilizing balance differential amplifier stage

摘要

A closed-loop emission control system for an internal combustion engine having an exhaust composition sensor includes an averaging circuit for generating a signal representative of the average value of the sensed exhaust composition, and a balanced differential amplifier receptive of the average and instantaneous values of the sensed composition to generate an output indicating the difference therebetween. A DC bias is applied to the differential amplifier to fluctuate the difference signal above and below the DC bias level.