Methodology of robust initialization of catalyst for consistent oxygen storage capacity measurement

A catalytic converter monitor apparatus, comprising:

• a first oxygen sensor mounted in a vehicle exhaust system upstream of a catalytic converter catalyst;
• a second oxygen sensor mounted in the vehicle exhaust system downstream of at least a portion of the catalytic converter catalyst;
• and
• an electronic controller coupled to said first and second oxygen sensors and to a vehicle engine, said vehicle engine provides an input signal indicative of an engine operating condition to the electronic controller, said electronic controller further comprising:
• a control algorithm, said control algorithm determining an oxygen storage capacity of said catalytic converter;
• and
• an adaptive table modifier, for updating a table as said catalytic converter ages;
• wherein said control algorithm forces said catalytic converter into a stable saturated state, said stable saturated state corresponding to a lean air to fuel ratio after a predetermined time, said control algorithm further forcing said catalytic converter into a rich air to fuel ratio and measuring the time delay between said first oxygen sensor and said second oxygen sensor, said first oxygen sensor being positioned at the inlet of said catalytic converter and said second oxygen sensor being positioned at an outlet of said catalytic converter, said time delay corresponding to the oxygen storage capacity of said catalytic converter, said algorithm further normalizing the oxygen storage capacity to define a normalized oxygen storage capacity value and the normalized oxygen storage capacity value is compared to a threshold value, said threshold value indicating a properly operating catalytic converter.

A method for measuring the oxygen storage capacity of a catalytic converter, comprising:

• stabilizing an engine of a vehicle;
• capturing catalyst operating state data;
• setting proportional fuel control to zero;
• forcing said catalytic converter into a stable saturated state, said stable saturated state corresponding to a lean air to fuel ratio;
• changing said saturated state to a rich air to fuel ratio;
• measuring the time delay between a first oxygen sensor and a second oxygen sensor, said time delay corresponding to the oxygen storage capacity of said catalytic converter, said first oxygen sensor being positioned at the inlet of said catalytic converter and said second oxygen sensor being positioned at an outlet of said catalytic converter;
• normalizing the oxygen storage capacity to define a normalized oxygen storage capacity value;
• and
• comparing said normalized oxygen storage capacity value to a threshold value.

A method for measuring the oxygen storage capacity of a catalytic converter in a vehicle, comprising:

• stabilizing an engine of a vehicle;
• checking enabling conditions of said vehicle;
• determining whether enabling conditions are met;
• forcing the fuel control of said vehicle from a closed loop to an opening loop control;
• setting a proportional fuel control to zero;
• forcing said catalytic converter into a stable saturated state, said stable saturated state corresponding to a lean air to fuel ratio;
• changing said saturated state to a rich air to fuel ratio;
• measuring the time delay between a first oxygen sensor and a second oxygen sensor, said time delay corresponding to the oxygen storage capacity of said catalytic converter, said first oxygen sensor being positioned at the inlet of said catalytic converter and said second oxygen sensor being positioned at an outlet of said catalytic converter;
• normalizing the oxygen storage capacity to define a normalized oxygen storage capacity value;
• and
• comparing said normalized oxygen storage capacity value to a threshold value.