Patent ID: 8887490

Claim:
A system comprising: a catalyst; a first oxygen sensor configured to detect oxygen content of gases entering the catalyst and to report the oxygen content of the gases entering the catalyst to an emissions control module; a second oxygen sensor disposed within a catalyst brick of the catalyst and configured to detect oxygen content of the gases within the catalyst and to report the oxygen content of the gases within the catalyst to the emissions control module; a third oxygen sensor configured to detect oxygen content of gases exiting the catalyst and to report the oxygen content of the gases exiting the catalyst to the emissions control module; a carbon monoxide sensor configured to detect carbon monoxide content of gases exiting the catalyst and to report the carbon monoxide content of the gases exiting the catalyst to the emissions control module; and the emissions control module comprises a memory and a processor, wherein the processor is configured to access and execute one or more routines encoded by the memory that when executed determine an air-fuel ratio based on the oxygen content of the gases entering the catalyst, the oxygen content of the gases within the catalyst, and both the oxygen content and the carbon monoxide content of the gases exiting the catalyst, and to control an air-fuel regulator to operate an engine at the air-fuel ratio.