US 2002/0120386 A1 · Method and apparatus for determining oxygen storage capacity time of a catalytic converter

Abstract

An on-board catalyst diagnostic for monitoring the conversion efficiencies of a catalytic converter by measuring the oxygen storage capacity (OSC) of the converter. The measurement of the OSC indicates the degree of health of the converter. Under the same engine running conditions, the greater the OSC measurement, the healthier the converter. A modeled OSC is compared to the real OSC to determine a normalized OSC. The normalized OSC is compared to a predetermined threshold value in order to determine the health of the converter. The modeled OSC takes into consideration variables which will affect the value of the OSC.

Claims4

Dependent claims

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

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 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.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application

09/794,607Filed 27 Feb 2001

Published

29 Aug 2002

Term ends

Not estimatedThe source records don’t support an estimate.

Classification6 codes

F01N 11/007
Monitoring or diagnostic devices for exhaust-gas treatment apparatus: the diagnostic devices measuring oxygen or air concentration downstream of…
F01N 2550/02
Monitoring or diagnosing the deterioration of exhaust systems: catalytic activity of catalytic converters
F01N 2900/0422
Methods of control or diagnosing: measuring the elapsed time
Y02T 10/40
Internal combustion engine [ICE] based vehicles: engine management systems

Method and apparatus for determining oxygen storage capacity time of a catalytic converter

Life of this patent

Method and apparatus for determining oxygen storage capacity time of a catalytic converter

Life of this patent

Abstract

Claims4