Purge valve leak diagnostic systems and methods
AssigneeGM Global Technology Operations LLC
InventorsZhong Wang, Miles K. Maxey, James D. Ethington, Eric M. Hall, Brian Spohn, David Edward Prout
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Abstract
A leak diagnostic system for a vehicle comprises a tank pressure module and a leak diagnostic module. The tank pressure module selectively outputs first and second fuel tank pressures when an engine is shut down and when engine vacuum is greater than a predetermined engine vacuum, respectively. The leak diagnostic module selectively diagnoses a leak in a fuel vapor purge valve based on the second fuel tank pressure when the first fuel tank pressure is less than a first predetermined pressure.
Claims20
A leak diagnostic system for a vehicle, comprising:
- a tank pressure module that selectively outputs first and second fuel tank pressures when an engine is shut down and when engine vacuum is greater than a predetermined engine vacuum, respectively;
- and
- a leak diagnostic module that selectively diagnoses a leak in a fuel vapor purge valve based on said second fuel tank pressure when said first fuel tank pressure is less than a first predetermined pressure.
A leak diagnostic method for a vehicle, comprising:
- selectively outputting first and second fuel tank pressures when an engine is shut down and when engine vacuum is greater than a predetermined engine vacuum, respectively;
- and
- selectively diagnosing a leak in a fuel vapor purge valve of said vehicle based on said second fuel tank pressure when said first fuel tank pressure is less than a first predetermined pressure.
Dependencies are inferred from the claim text.