Systems and methods for refueling canister system

摘要

Methods and systems are described for depressurizing a fuel tank prior to refueling. In one example, before refueling the fuel tank having a pressure above a first predetermined pressure, the pressure may be released through a first valve to the first predetermined pressure and the first valve may be closed. Further, a second valve may be opened to further reduce the pressure to a second predetermined pressure, and if flow through the second valve is less than desired, then the first valve may be opened until the second predetermined pressure is reached.

主权项

1. A method comprising:
before refueling a fuel tank having a pressure above a first predetermined pressure, releasing said pressure through a first valve to said predetermined pressure and then closing said first valve and opening a second valve to further reduce said pressure to a second predetermined pressure; and if flow through said second valve is less than desired, then opening said first valve until said second predetermined pressure is reached.