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US 6,957,562 B2Granted
Passive oxygen sensor diagnostic
AssigneeGeneral Motors Corporation
InventorsIgor Anilovich, Thomas L. Ting
Life of this patent
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Abstract
An engine exhaust sensor diagnostic system includes an oxygen sensor and a controller. The controller monitors a signal generated by the oxygen sensor, determines a rate of change of the signal, and computes diagnostic parameters. The controller indicates malfunction of the oxygen sensor if the diagnostic parameters are smaller in magnitude than corresponding thresholds.
Claims15
An engine exhaust sensor diagnostic system, comprising:
- an inlet oxygen sensor;
- and
- a controller that monitors a signal generated by said oxygen sensor, determines a rate of change of said signal, computes at least one diagnostic parameter based on said rate of change, and indicates a malfunction of said oxygen sensor if said diagnostic parameter is below a corresponding threshold, wherein said controller classifies said rate of change into one of a positive class, a negative class and an excluded class.
A method of monitoring operability of an oxygen sensor, comprising:
- monitoring a signal generated by said oxygen sensor;
- determining a rate of change of said signal;
- classifying said rate of change into one of a positive class, a negative class and an excluded class;
- computing diagnostic parameters based on said rate of change;
- and
- indicating malfunction of said oxygen sensor if said diagnostic parameters are below corresponding thresholds.
3 more elements
A method of diagnosing operability of a sensor, comprising:
- monitoring a signal generated by said sensor;
- determining a rate of change of said signal;
- classifying said rate of change in one of a positive class, a negative class and an excluded class;
- computing diagnostic parameters for each of said classes based on said rate of change;
- indicating malfunction of said sensor if said positive class diagnostic parameters are below positive class thresholds;
- and
- indicating malfunction of said sensor if said negative class diagnostic parameters are below negative class thresholds.
4 more elements
Dependencies are inferred from the claim text.