Method for selecting a cylinder group when changing an engine operational parameter

A method for selecting one of first and second cylinder groups of an internal combustion engine, said first and second cylinder groups being coupled with first and second catalytic converters, respectively, wherein a first air/fuel ratio in said first cylinder group oscillates about a first predetermined air/fuel ratio, and wherein a second air/fuel ratio in said second cylinder group oscillates about a second predetermined air/fuel ratio, said method comprising:

• determining whether one of said first and second catalytic converters has a larger catalyst volume using a controller;
• and,
• selecting one of said first and second cylinder groups coupled to said catalytic converter having said larger catalyst volume for changing an engine operational parameter in said selected group.

A method for selecting one of first and second cylinder groups of an internal combustion engine, said first and second cylinder groups being coupled with first and second catalytic converters, respectively, said method comprising:

• determining whether one of said first and second catalytic converters has a greater amount of catalyst material using a controller;
• and,
• selecting one of said first and second cylinder groups coupled to said catalytic converter having said larger amount of catalyst material for changing an engine operational parameter in said selected group.

An article of manufacture for selecting one of first and second cylinder groups of an internal combustion engine, said first and second cylinder groups being coupled with first and second catalytic converters, respectively, said article of manufacture comprising:

• a computer usable medium;
• and,
• a computer readable program code embodied in said medium for identifying one of said first and second catalytic converters using first and second catalyst parameters, respectively, and for selecting one of said first and second cylinder groups coupled to said identified catalytic converter for phase shifting air/fuel ratio oscillations in said selected group, said selection being made to reduce engine emissions during said phase shift.

A method for selecting one of first and second cylinder groups of an internal combustion engine, the first and second cylinder groups being coupled to first and second emission control devices, respectively, the method comprising:

• indicating when said first catalyst can more efficiently reduce engine emissions compared to said second catalyst based on an catalyst structural parameter, said indication being made by a controller;
• and,
• selecting said first cylinder group connected to said first catalyst for changing an engine operational parameter in said selected group, said selection being made to reduce emissions during said change of said engine operational parameter.