Method for controlling the phase difference of air/fuel ratio oscillations in an engine
AssigneeFord Global Technologies, LLC
InventorsRichard Andrew Booth, Brent Edward Sealy, Kenneth John Behr
Life of this patent
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Abstract
A method for controlling the phasing of first and second air/fuel ratio oscillations in first and second cylinder groups, respectively, of an internal combustion engine is provided. The method includes determining a phase difference between the first air/fuel ratio oscillations and the second air/fuel ratio oscillations. The method further includes adjusting a phase of the first air/fuel ratio oscillations so that both first and second air/fuel ratio oscillations are at a predetermined phase offset with respect to one another, while maintaining an average air/fuel bias in the first cylinder group.
Claims12
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.
A system for controlling phasing of air/fuel ratio oscillation cycles in first and second cylinder groups of an engine, the system comprising:
- a first sensor communicating with exhaust gases from said first cylinder group, said first sensor generating a first signal that over time is indicative of air/fuel ratio oscillation cycles in said first cylinder group;
- a second sensor communicating with exhaust gases from said second cylinder group, said second sensor generating a second signal that over time is indicative of air/fuel ratio oscillation cycles in said second cylinder group;
- a controller receiving said first and second signals, said controller 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, said controller further 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.
Dependencies are inferred from the claim text.