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US 8,769,929 B2Granted
Exhaust system with a NOx sensor
AssigneeFord Global Technologies, LLC
InventorDavid Charles Weber
Life of this patent
Estimating the term…
Abstract
Various systems and methods are described for controlling a NOx sensor coupled to an engine exhaust system in a motor vehicle. One example method comprises generating an offset of the sensor based on an ambient air flow drawn into the exhaust system, the ambient air flow having circumvented cylinders of the engine, and adjusting an output of the sensor based on the generated offset.
Claims9
An engine control method, comprising:
- before an engine start, exposing an exhaust gas sensor having a heater coupled in an engine exhaust system to ambient air both upstream and downstream of the sensor;
- upon the engine start, activating the sensor heater to heat the sensor even if temperature of combusted exhaust gas from the engine start is below a dew point temperature of the combusted exhaust gas while maintaining exposure of the sensor to ambient air both upstream and downstream of the sensor, including exposing the sensor to ram air circumventing the engine.
An engine control method, comprising:
- before engine start, exposing an exhaust NOx sensor having a heater to ambient air both upstream and downstream of the sensor;
- upon engine start, activating the heater to heat the sensor even if combusted engine exhaust gas temperature is below an exhaust dew point, while maintaining exposure of the sensor to ambient air both upstream and downstream of the sensor including exposing the sensor to ram air circumventing the engine;
- and
- adjusting urea injection responsive to the sensor.
1 more element
An engine control method, comprising:
- before engine start, exposing an exhaust NOx sensor having a heater to ambient air both upstream and downstream of the sensor;
- upon engine start, activating the heater to heat the sensor even if combusted engine exhaust gas temperature is below an exhaust dew point, while maintaining exposure of the sensor to ambient air both upstream and downstream of the sensor,
- once the exhaust gas dew point is above a threshold temperature, exposing the sensor to combusted exhaust gas from the engine and not exposing the sensor to ambient air upstream of the sensor;
- and
- adjusting urea injection responsive to the sensor.
2 more elements
Dependencies are inferred from the claim text.