Air/fuel ratio control system

摘要

A nitrous oxide trap temperature control system for desulfating the trap uses and engine with some cylinders operating with lean combustion and some cylinders operating with rich combustion. The lean and rich combustion gases are combined to form an mixture which is fed to the trap to provide an exothermic reaction. The desired lean and rich air/fuel ratios of the respective lean and rich cylinders are determined based in part on the difference between the trap temperature and a desired trap temperature. The desired lean and rich air/fuel ratios of the respective lean and rich cylinders are also determined from the desired mixture air/fuel ratio entering the trap.