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US 9,518,529 B2Granted
Methods and systems for an intake oxygen sensor
AssigneeFord Global Technologies, LLC
InventorsGopichandra Surnilla, Timothy Joseph Clark, James Alfred Hilditch, Matthew John Gerhart
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Abstract
Methods and systems are provided for correcting an EGR rate determined based on an intake manifold oxygen sensor based on an air-fuel ratio of EGR. The output of the sensor is corrected to compensate for extra fuel in rich EGR or extra air in lean EGR and used to reliably estimate the EGR rate. One or more engine operating parameters are adjusted based on an uncorrected output of the sensor.
Claims20
A method for an engine, comprising:
- in response to an EGR air-fuel ratio being richer than a threshold,
- correcting an intake oxygen sensor output with a correction factor based on a richness of the EGR air-fuel ratio;
- and
- adjusting each of an EGR rate and a cylinder fuel injection based on the corrected intake oxygen sensor output.
1 more element
A method for an engine, comprising:
- during a first condition, when delivering EGR that is richer than a threshold air-fuel ratio,
- correcting an intake oxygen sensor output based on a richness of the EGR, adjusting each of an EGR rate and spark timing based on a corrected intake oxygen sensor output, and adjusting a fuel injection based on the corrected intake oxygen sensor output;
- and
- during a second condition when delivering EGR that is leaner than the threshold air-fuel ratio,
- adjusting the EGR rate based on an uncorrected intake oxygen sensor output, and adjusting each of spark timing and intake throttle position based on the uncorrected intake oxygen sensor output.
2 more elements
An engine system, comprising:
- an engine including an intake manifold and an exhaust manifold;
- an EGR passage including an EGR valve, the EGR passage coupling the exhaust manifold to the intake manifold;
- a first oxygen sensor coupled to the intake manifold, downstream of an outlet of the EGR passage and upstream of an intake throttle;
- a second oxygen sensor coupled to the exhaust manifold, upstream of an inlet of the EGR passage;
- and
- a controller with computer readable instructions for:
- estimating an air-fuel ratio of EGR based on an output of the second oxygen sensor;
- if an estimated air-fuel ratio of the EGR is richer than a stoichiometric air-fuel ratio, increasing an output of the first oxygen sensor based on a degree of richness while feed-forward adjusting an opening of the EGR valve based on an increased output of the first oxygen sensor;
- and
- if the estimated air-fuel ratio of the EGR is leaner than the stoichiometric air-fuel ratio, feed-forward adjusting the opening of the EGR valve based on an unadjusted output of the first oxygen sensor.
7 more elements
Dependencies are inferred from the claim text.