Patent ID: 6553982
Filing Date: 2003-04-29
Classification: F02D

Abstract:
A method for controlling phasing of air/fuel ratio oscillation cycles in first and second cylinder groups of an engine, each of said air/fuel ratio oscillation cycles having a portion rich of stoichiometry and a portion lean of stoichiometry, the method comprising:determining a phase difference between air/fuel ratio oscillation cycles in said first cylinder group and air/fuel ratio oscillation cycles in said second cylinder group; and, adjusting an elapsed time of either a lean or a rich portion of a first air/fuel ratio oscillation cycle in said first cylinder group to obtain a predetermined phase offset between said first air/fuel ratio oscillation cycle and a second air/fuel ratio oscillation cycle in said second cylinder group while maintaining a desired average air/fuel ratio in said first cylinder group either rich or lean of stoichiometry.