Method for controlling the frequency of air/fuel ratio oscillations in an engine

A method for matching the frequency of air/fuel ratio oscillations in first and second cylinder groups of an internal combustion engine, comprising:

• determining a first frequency of air/fuel ratio oscillations in said first cylinder group;
• determining a second frequency of air/fuel ratio oscillations in said second cylinder group;
• and,
• adjusting said first frequency towards said second frequency responsive to a frequency difference between said first and second frequencies;
• such adjusting including:
• providing a predetermined phase difference between the oscillations produced by first and second cylinder groups substantially at the common frequency.

A method for controlling the frequency of air/fuel ratio oscillations in first and second cylinder groups of an internal combustion engine, said method comprising:

• determining a first engine operational parameter indicative of a first frequency of air/fuel ratio oscillations in said first cylinder group;
• determining a second engine operational parameter indicative of a second frequency of air/fuel ratio oscillations in said second cylinder group;
• and,
• adjusting one of said first and second frequencies toward the other of said first and second frequencies responsive to a frequency difference between said first and second frequencies, such adjusting including:
• providing a predetermined phase difference between the oscillations produced by first and second cylinder groups substantially at the common frequency.

A method for controlling first and second cylinder groups of an internal combustion engine, comprising:

• generally increasing an amount of fuel delivered to said first cylinder group until exhaust gases from said first cylinder group transition to a rich state;
• generally decreasing an amount of fuel delivered to said first cylinder group until exhaust gases from said first cylinder group transition to a lean state;
• generally increasing an amount of fuel delivered to said second cylinder group until exhaust gases from said second cylinder group transition to a rich state;
• generally decreasing an amount of fuel delivered to said second cylinder group until exhaust gases from said second cylinder group transition to a lean state;
• and,
• delaying one of said lean or rich transitions in said first or second cylinder groups responsive to a frequency difference between a first frequency of said transitions of said first cylinder group and a second frequency of said transitions of said second cylinder group.

A control system for controlling first and second cylinder groups of an internal combustion engine, comprising:

• a first device for determining a first frequency of air/fuel ratio oscillations in said first cylinder group;
• a second device for determining a second frequency of air/fuel ratio oscillations in said second cylinder group;
• and,
• a controller operatively connected to said first and second devices, said controller adjusting said frequency of air/fuel ratio oscillations in said first cylinder group toward said frequency of air/fuel ratio oscillations in said second cylinder group responsive to a frequency difference between said first and second frequencies, such fuel adjusting including:
• providing a predetermined phase difference between the oscillations produced by first and second cylinder groups substantially at the common frequency.

An automotive vehicle, comprising:

• an internal combustion engine having first and second cylinder groups;
• a first device for determining a first frequency of air/fuel ratio oscillations in said first cylinder group;
• a second device for determining a second frequency of air/fuel ratio oscillations in said second cylinder group;
• and,
• a controller operatively connected to said internal combustion engine and said first and second devices, said controller adjusting said frequency of air/fuel ratio oscillations in said first cylinder group toward said frequency of air/fuel ratio oscillations in said second cylinder group responsive to a frequency difference between said first and second frequencies, such adjusting including:
• providing a predetermined phase difference between the oscillations produced by first and second cylinder groups substantially at the common frequency.

An article of manufacture for controlling the frequency of air/fuel ratio oscillations in an internal combustion engine having first and second cylinder groups, wherein an air/fuel ratio in said first cylinder group oscillates about a first predetermined air/fuel ratio at a first frequency, and wherein an air/fuel ratio in said second cylinder group oscillates about a second predetermined air/fuel ratio at a second frequency, said article of manufacture comprising:

• a computer usable medium;
• and,
• a computer readable program code embodied in said computer usable medium for determining said first frequency of said air/fuel ratio oscillations in said first cylinder group, and for adjusting a fuel injection amount in said second cylinder group responsive to said first frequency to move said second frequency toward said first frequency, such fuel adjusting including:
• providing a predetermined phase difference between the oscillations produced by first and second cylinder groups substantially at the common frequency.