Diagnostic systems and methods using nitrogen oxide sensors
AssigneeGM Global Technology Operations LLC
InventorsJoshua D. Cowgill, Scot A. Douglas
Life of this patent
Estimating the term…
Abstract
An engine system includes a nitrogen oxide (NOx) estimation module and a diagnostic module. The NOx estimation module estimates an amount of NOx in an exhaust gas produced by an engine based on a predetermined function of a position of at least one of a camshaft phaser and an exhaust gas recirculation (EGR) valve. The diagnostic module determines a state of at least one of the camshaft phaser and the EGR valve based on a predetermined threshold and a difference between the estimated amount of NOx and an actual amount of NOx in the exhaust gas measured by a NOx sensor.
Claims20
An engine system, comprising:
- a position control module that changes a position of at least one of a camshaft phaser and an exhaust gas recirculation (EGR) valve based on a first nitrogen oxide (NOx) level in an exhaust gas produced by an engine;
- a NOx estimation module that estimates an amount of NOx in the exhaust gas within a predetermined period after the change of position of at least one of the camshaft phaser and the EGR valve, wherein the estimated amount of NOx is based on a plurality of predetermined NOx amounts corresponding to a plurality of changes of position of at least one of the camshaft phaser and the EGR valve;
- and
- a diagnostic module that determines a state of at least one of the camshaft phaser and the EGR valve based on a predetermined threshold and a difference between the estimated amount of NOx and a second NOx level, wherein the first and second NOx levels are measured using a NOx sensor.
An engine system, comprising:
- a nitrogen oxide (NOx) estimation module that estimates an amount of NOx in an exhaust gas produced by an engine based on a predetermined function of a position of at least one of a camshaft phaser and an exhaust gas recirculation (EGR) valve;
- and
- a diagnostic module that determines a state of at least one of the camshaft phaser and the EGR valve based on a predetermined threshold and a difference between the estimated amount of NOx and an actual amount of NOx in the exhaust gas measured by a NOx sensor.
A method, comprising:
- changing a position of at least one of a camshaft phaser and an exhaust gas recirculation (EGR) valve based on a first nitrogen oxide (NOx) level in an exhaust gas produced by an engine;
- estimating an amount of NOx in the exhaust gas within a predetermined period after the change of position of at least one of the camshaft phaser and the EGR valve, wherein the estimated amount of NOx is based on a plurality of predetermined NOx amounts corresponding to a plurality of changes of position of at least one of the camshaft phaser and the EGR valve;
- and
- determining a state of at least one of the camshaft phaser and the EGR valve based on a predetermined threshold and a difference between the estimated amount of NOx and a second NOx level, wherein the first and second NOx levels are measured using a NOx sensor.
A method, comprising:
- estimating an amount of NOx in an exhaust gas produced by an engine based on a predetermined function of a position of at least one of a camshaft phaser and an exhaust gas recirculation (EGR) valve;
- and
- determining a state of at least one of the camshaft phaser and the EGR valve based on a predetermined threshold and a difference between the estimated amount of NOx and an actual amount of NOx in the exhaust gas measured by a NOx sensor.
Dependencies are inferred from the claim text.