Hybrid vehicle exhaust diagnostics

摘要

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.

主权项

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, the monitoring test including monitoring a rich to lean transition upstream and downstream of a catalyst in an exhaust of the vehicle, inhibiting engine shutdown when exhaust gas sensors upstream and downstream of the catalyst are reading rich, and not inhibiting engine shutdown when exhaust gas sensors upstream and downstream of the catalyst are reading lean.