Patent ID: 6631611
Filing Date: 2003-10-14
Classification: F01N,F02D,F02M,F02P,Y02T

Abstract:
A method for measuring the oxygen storage capacity of a catalytic converter on board a vehicle, comprising:calculating an average Fuel Short Term Integrator (STI); holding the value of said average Fuel Short Term Integrator (STI) in a fuel control subsystem throughout a measuring period of said oxygen storage capacity; ramping an air/fuel ratio of an engine of said vehicle during said measuring period; adjusting spark, air and fuel mixtures to said engine during said measuring period; 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 reaching a predetermined value corresponding to said first oxygen sensor and a second oxygen sensor reaching a predetermined value corresponding to 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.