Air/fuel ratio validation for lean burn
First Claim
1. A multi-cylinder group engine system operable in at least a first mode and a second mode, where in the first mode a first and second cylinder group combust air and fuel, and where in the second mode at least one of the first and second cylinder group combusts air and fuel and the other one of the first and second cylinder group pumps air without injected fuel, the engine system comprising:
- a first linear exhaust gas sensor disposed in a first exhaust passage to measure air fuel exhausted from the first cylinder group;
a second exhaust gas sensor disposed in a second exhaust passage to measure air-fuel exhausted from the second cylinder group;
a third linear exhaust gas sensor disposed downstream of a junction between the first exhaust passage and the second exhaust passage; and
a controller configured to validate a reading of the first linear exhaust gas sensor during the first mode of engine operation based on a reading of the second linear exhaust gas sensor when a lean air-fuel ratio is commanded.
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Accused Products
Abstract
A multi-cylinder group engine system operable in at least a first mode and a second mode, where in the first mode a first and second cylinder group combust air and fuel, and where in the second mode at least one of the first and second cylinder group combusts air and fuel and the other one of the first and second cylinder group pumps air without injected fuel, the engine system comprising of a first linear exhaust gas sensor disposed in a first exhaust passage to measure air fuel exhausted from the first cylinder group; a first switching type exhaust gas sensor disposed in a second exhaust passage to measure air-fuel exhausted from the second cylinder group; a second linear exhaust gas sensor disposed downstream of a junction between the first exhaust passage and the second exhaust passage; and a controller configured to validate a reading of the first linear exhaust gas sensor during the first mode of engine operation based on a reading of the second linear exhaust gas sensor when a lean air-fuel ratio is commanded.
60 Citations
20 Claims
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1. A multi-cylinder group engine system operable in at least a first mode and a second mode, where in the first mode a first and second cylinder group combust air and fuel, and where in the second mode at least one of the first and second cylinder group combusts air and fuel and the other one of the first and second cylinder group pumps air without injected fuel, the engine system comprising:
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a first linear exhaust gas sensor disposed in a first exhaust passage to measure air fuel exhausted from the first cylinder group;
a second exhaust gas sensor disposed in a second exhaust passage to measure air-fuel exhausted from the second cylinder group;
a third linear exhaust gas sensor disposed downstream of a junction between the first exhaust passage and the second exhaust passage; and
a controller configured to validate a reading of the first linear exhaust gas sensor during the first mode of engine operation based on a reading of the second linear exhaust gas sensor when a lean air-fuel ratio is commanded. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system comprising:
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an engine including a first cylinder group and a second cylinder group;
an exhaust system coupled to the engine, wherein the first cylinder group exhausts gas into at least a first exhaust passage and the second cylinder group exhausts gas into at least a second exhaust passage;
a first linear exhaust gas sensor disposed in the first exhaust passage;
a first switching type exhaust gas sensor disposed in the second exhaust passage;
a second linear exhaust gas sensor disposed downstream from a junction of the first exhaust passage and the second exhaust passage; and
a controller configured to operate the engine in a first mode where the first and second cylinder groups combust air and fuel, and a second mode where at least one of the first and second cylinder groups combusts air and fuel and the other one of the first and second cylinder groups pumps air without injecting fuel, and the controller is further configured to validate a reading of the first linear exhaust gas sensor based on a reading of the second linear exhaust gas sensor during the first mode of engine operation when a lean air-fuel ratio is commanded. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method for detecting exhaust gas sensor degradation in an engine system, the engine having an asymmetric exhaust gas sensor configuration to provide air-fuel feedback for control of engine output, the method comprising:
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measuring lean air-fuel ratio readings over a first duration by a first linear exhaust gas sensor;
measuring lean air-fuel ratio readings over a second duration by a second linear exhaust gas sensor downstream from the first linear exhaust gas sensor based on detection of oxygen breakthrough in a catalyst;
shifting the first measurement duration to correspond to the second measurement duration based on an exhaust gas transportation duration;
comparing the air-fuel ratio readings of the first and second sensor during the corresponding measurement durations; and
setting a degradation condition responsive to a discrepancy between the readings of the first and second sensors during the corresponding measurement durations. - View Dependent Claims (18, 19, 20)
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Specification