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US 11,149,698 B2Granted
Systems and methods for fuel system recirculation valve diagnostics
AssigneeFord Global Technologies, LLC
InventorAed M. Dudar
Life of this patent
Estimating the term…
Abstract
Methods and system are provided for indicating whether a variable orifice valve positioned in a fuel vapor recovery line of a vehicle fuel system is degraded. In one example, a method may include actively manipulating a pressure in the fuel system during a refueling event, and indicating whether the variable orifice valve is degraded based on a loading rage of a fuel vapor storage canister with fuel vapors while the pressure is actively manipulated. In this way, it may be determined as to whether the variable orifice valve is stuck in a high-flow or a low-flow position such that mitigating action may be taken to reduce or avoid release of undesired evaporative emissions to atmosphere.
Claims18
A method for a vehicle, comprising:
- during refueling a fuel tank positioned in a fuel system of the vehicle, actively manipulating a pressure in the fuel system with a fuel tank isolation valve kept open, the fuel system fluidically coupled to an evaporative emissions system including a fuel vapor canister;
- and
- indicating whether a variable orifice valve positioned in a fuel vapor recirculation line upstream of the fuel tank isolation valve of the fuel system is degraded based on a rate of loading of the canister with fuel vapors while the pressure is actively manipulated,
- wherein actively manipulating the pressure includes increasing the pressure by duty cycling a canister vent valve to periodically seal the fuel system and evaporative emissions system from atmosphere, or decreasing the pressure by duty cycling a canister purge valve to periodically fluidically couple the fuel system and the evaporative emissions system to an intake of an engine of the vehicle.
1 more element
A method, comprising:
- during refueling a fuel tank positioned in a fuel system of a vehicle, in a first condition, operating an evaporative emissions system selectively fluidically coupled to the fuel tank in a first mode to decrease pressure in the fuel tank;
- in a second condition, during refueling the fuel tank, operating the evaporative emissions system in a second mode to increase pressure in the fuel tank;
- and
- in both the first condition and the second condition, indicating whether a variable orifice valve positioned in a vapor recirculation line upstream of a fuel tank isolation valve of the fuel system is degraded based on a rate at which a fuel vapor canister is loaded with fuel vapors during the decreasing pressure and the increasing pressure, respectively, wherein the fuel tank isolation valve is kept open in both the first condition and the second condition,
- wherein operating the evaporative emissions system in the first mode to decrease pressure in the fuel system includes duty cycling a canister purge valve positioned in a purge line to periodically fluidically couple the evaporative emissions system to an intake of an engine, and
- wherein operating the evaporative emissions system in the second mode to increase pressure in the fuel system includes duty cycling a canister vent valve positioned in a vent line to periodically seal the fuel system and evaporative emissions system from atmosphere.
3 more elements
A system for a vehicle, comprising:
- a fuel system including a fuel tank and a fuel vapor recirculation line for recirculating fuel vapors back to the fuel tank;
- a variable orifice valve positioned in the fuel vapor recirculation line upstream of a fuel tank isolation valve;
- an evaporative emissions system fluidically coupled to the fuel system, the evaporative emissions system including a fuel vapor storage canister;
- a canister purge valve positioned in a purge line selectively fluidically coupling the fuel vapor storage canister to an intake of an engine;
- a canister vent valve positioned in a vent line selectively fluidically coupling the fuel vapor storage canister to atmosphere;
- and
- a controller with computer readable instructions stored on non-transitory memory that, when executed, cause the controller to:
- during a refueling event, actively manipulate pressure in the fuel system via duty cycling either the canister purge valve or the canister vent valve while keeping the fuel tank isolation valve open;
- and
- indicate whether the variable orifice valve is degraded based on a rate at which the fuel vapor storage canister is loaded with fuel vapors during the actively manipulating pressure in the fuel system,
- wherein actively manipulating the pressure includes increasing the pressure by duty cycling a canister vent valve to periodically seal the fuel system and evaporative emissions system from atmosphere, or decreasing the pressure by duty cycling a canister purge valve to periodically fluidically couple the fuel system and the evaporative emissions system to an intake of an engine of the vehicle.
8 more elements
Dependencies are inferred from the claim text.