Monitoring of Exhaust Gas Oxygen Sensor Performance
AssigneeFord Global Technologies, LLC
InventorAvra Brahma
Life of this patent
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Abstract
A method of monitoring a performance of an oxygen sensor is disclosed. One embodiment comprises determining a first air/fuel ratio from a signal from an exhaust oxygen sensor; determining a second air/fuel ratio from a temperature upstream of the particulate filter, a pressure differential across the particulate filter and one or more of an airflow into the engine and a fuel flow into the engine; comparing the first air/fuel ratio and the second air/fuel ratio; and diagnosing an error condition of the oxygen sensor if the first air/fuel ratio does not meet a predetermined condition relative to the second air/fuel ratio.
Claims17
In an apparatus comprising an internal combustion engine, an exhaust conduit, a particulate filter disposed along the exhaust conduit, an oxygen sensor disposed along the exhaust conduit, and a pressure sensor disposed along the exhaust conduit, a method of diagnosing a performance of an oxygen sensor, comprising:
- determining a first air/fuel ratio from a signal from an exhaust oxygen sensor;
- determining a second air/fuel ratio from a temperature upstream of the particulate filter, a pressure differential across the particulate filter and one or more of an airflow into the engine and a fuel flow into the engine;
- comparing the first air/fuel ratio and the second air/fuel ratio;
- and
- diagnosing an error condition of the oxygen sensor if the first air/fuel ratio does not meet a predetermined condition relative to the second air/fuel ratio.
In an apparatus comprising an internal combustion engine, an exhaust conduit, a particulate filter disposed along the exhaust conduit, an oxygen sensor disposed along the exhaust conduit, and a pressure sensor disposed along the exhaust conduit, a method of monitoring a performance of the oxygen sensor, comprising:
- determining whether an air/fuel ratio supplied to the engine is richer or leaner than a preselected air/fuel ratio;
- determining a first air/fuel ratio from a signal received from the oxygen sensor;
- if the air/fuel ratio supplied to the engine is rich, determining a second air/fuel ratio from a pressure upstream of the particulate filter and a fuel flow into the engine;
- if the air/fuel ratio supplied to the engine is lean, determining a third air/fuel ratio from the pressure upstream of the particulate filter and an air flow into the engine;
- comparing first air/fuel ratio with the second or third air/fuel ratio;
- and
- diagnosing an error condition of the oxygen sensor if the first air/fuel ratio does not meet a predetermined condition relative to the second or third air/fuel ratio.
An apparatus comprising
- an internal combustion engine;
- an exhaust conduit;
- a particulate filter disposed along the exhaust conduit;
- an oxygen sensor disposed along the exhaust conduit;
- a pressure sensor disposed along the exhaust conduit;
- and
- a controller configured to determine a first air/fuel ratio from a signal from the oxygen sensor, to determine a second air/fuel ratio from a pressure differential upstream of particulate filter and one or more of an airflow into the engine and a fuel flow into the engine, to compare the first air/fuel ratio and the second air/fuel ratio, and to diagnose an error condition of the oxygen sensor if the first air/fuel ratio does not meet a predetermined condition relative to the second air/fuel ratio.
Dependencies are inferred from the claim text.