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US 2014/0277998 A1Published application
Hybrid vehicle exhaust diagnostics
AssigneeFord Global Technologies, LLC
InventorsDouglas Raymond Martin, Richard Paul Taylor, Matthew D. Smith
Life of this patent
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Abstract
Methods are provided for performing diagnostic routines in a hybrid vehicle. In one example approach, a method for operating a hybrid vehicle comprises inhibiting engine shutdown and enabling deceleration fuel shut off to perform a monitoring test while a vehicle speed is above a threshold speed.
Claims20
A method for a hybrid vehicle with an engine, comprising:
- inhibiting engine shutdown and enabling deceleration fuel shut off to perform a monitoring test while a vehicle speed is above a threshold speed.
A method for a hybrid vehicle, comprising:
- in response to an engine pull-down request when a vehicle speed is greater than a threshold speed:
- inhibiting engine shutdown;
- enabling deceleration fuel shut off with the engine still spinning;
- monitoring a rich to lean transition in an exhaust of the vehicle;
- and
- indicating a degradation based on the rich to lean transition.
3 more elements
A method for a hybrid vehicle, comprising:
- in response to an engine pull-down request when a vehicle speed is greater than a first threshold speed:
- inhibiting engine shutdown;
- enabling deceleration fuel shut off;
- monitoring a rich to lean transition at an air/fuel sensor in an exhaust of the vehicle;
- indicating sensor degradation based on the rich to lean transition at the air/fuel sensor;
- and
- shutting down the engine after monitoring the rich to lean transition at the air/fuel sensor for a duration;
- and
- in response to an engine pull-down request when the vehicle speed is greater than a second threshold speed less than the first threshold speed:
- inhibiting engine shutdown;
- enabling deceleration fuel shut off;
- monitoring a rich to lean transition upstream and downstream of a catalyst in an exhaust of the vehicle;
- and
- indicating catalyst degradation based on the rich to lean transition upstream and downstream of the catalyst;
- and
- shutting down the engine after monitoring the rich to lean transition upstream and downstream of the catalyst for a duration.
13 more elements
Dependencies are inferred from the claim text.