HYBRID VEHICLE EXHAUST DIAGNOSTICS
First Claim
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1. 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.
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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.
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Citations
20 Claims
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1. 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. 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. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A method for a hybrid vehicle, comprising:
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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. - View Dependent Claims (19, 20)
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Specification