Patent ID: 6694244
Filing Date: 2004-02-17
Classification: F01N,F02D,Y02T

Abstract:
A system for quantifying oxygen stored in an emission control device that receives exhaust gas generated by an internal combustion engine, wherein the device is filled with a constituent gas of the exhaust gas during a first engine operating condition and is purged of constituent gas during a second engine operating condition, the system comprising:an oxygen sensor generating an output signal representative of a concentration of oxygen present in the exhaust flowing through the device during a sampling period; and a control module including a microprocessor arranged to operate in a normal open-loop mode of operation by determining fill times and purge times based on engine operating conditions and corresponding values stored in a memory, wherein the control module is further arranged to periodically generate a first and second sub-optimal fill time, and determine corresponding first and second actual purge times required for purging constituent gas stored in the device during the first and second fill times, and to determine a value representative of the quantity of oxygen stored in the device as a function of both the first and second fill times, and the first and second actual purge times.