Method and system for controlling air/fuel level in two-bank exhaust system

摘要

A method and system for adjusting a fuel injection amount in one of two groups of cylinders in an internal combustion engine (12) using feedback signals generated by oxygen sensors (38,42,46) coupled to both groups of cylinders. The claimed invention includes first and second groups of engine cylinders coupled to first and second exhaust banks (34,36) respectively. The first exhaust bank (34) includes at least a pre-catalyst EGO sensor (38) for generating a first feedback signal. The second exhaust bank (36) includes a post-catalyst EGO sensor (46) for generating a second feedback signal. A controller (202) calculates desired air/fuel ratio values for the first group of cylinders based on the first feedback signal. The controller (202) also calculates desired air/fuel ratio values for the second group of cylinders based on the first feedback signal and the second feedback signal. The controller (202) adjusts the level of liquid fuel injected into the groups of cylinders based on the calculated air/fuel ratio values. <IMAGE>