Fuel system control
AssigneeFord Global Technologies, LLC
InventorsRobert Roy Jentz, John Mullins, Aed M. Dudar, Mark W. Peters
Life of this patent
Estimating the term…
Abstract
Methods are provided for reliving excess vacuum from a fuel tank. In response to elevated fuel tank vacuum levels, a canister purge valve is opened to dissipate the vacuum to an engine intake manifold while the engine is not combusting. Alternatively, the purge valve is opened to dissipate the excess vacuum to the intake manifold while the engine is combusting during conditions when the likelihood of air-fuel ratio errors are lower or when any incurred errors are better tolerated.
Claims20
A method for a fuel system coupled to an engine, comprising:
- in response to fuel tank vacuum level,
- opening a canister purge valve to dissipate excess fuel tank vacuum into an engine intake manifold while the engine is not combusting, a timing of the opening based on engine operating conditions.
A method for a fuel system coupled to an engine in a hybrid electric vehicle, comprising:
- in response to fuel tank vacuum being higher than a threshold level when the vehicle is operating in an engine mode, opening a canister purge valve to dissipate excess fuel tank vacuum to an engine intake when the vehicle is operating in a battery mode.
A method for a fuel system coupled to an engine having selectively deactivatable fuel injectors, comprising:
- in response to fuel tank vacuum being higher than a threshold level while the engine is combusting, selectively deactivating the engine and opening a canister purge valve to dissipate excess fuel tank vacuum after the deactivation.
A method for a fuel system coupled to an engine, comprising:
- in response to a rise in fuel tank vacuum above a threshold;
- opening a canister purge valve to dissipate excess fuel tank vacuum into an engine intake manifold, a timing of the opening based on intake manifold vacuum.
Dependencies are inferred from the claim text.