The present description provides low DBL bleed emission performance properties that allows the design of evaporative fuel emission control systems that are simpler and more compact than those possible by prior art by inclusion of a vent-side volume comprising a parallel passage adsorbent such as a carbon honeycomb with narrow channel width and low cell pitch.

Methods and systems are presented for operating a refueling valve of an evaporative emissions system. The methods and systems may attempt to reactivate a refueling valve that has stuck due to the refueling valve being exposed to liquid fuel. In one example, a voltage that is applied to the refueling valve may be increased to reactivate the refueling valve.

A method of controlling an evaporative emissions system for a vehicle is provided. A fuel system for a vehicle and a vehicle are also provided. A signal indicative of an entry condition associated with a secondary air flow path for a purge of an evaporative emissions canister is received. A filter is decoupled from a port of the evaporative emissions canister in response to receiving the signal and prior to the evaporative emissions canister purge. The evaporative emissions canister is purged by flowing atmospheric air into the port and through the evaporative emissions canister while the filter is decoupled from the port. The filter is coupled to the port of the evaporative emissions canister after purging the canister.

Disclosed is a fuel evaporation gas treatment system for a vehicle, which includes a sub-purge system configured such that a fuel evaporation gas adsorbed in a canister is recovered into a fuel tank, the sub-purge system including a recovery port formed in the canister, a recovery line connected to the recovery port, an ejector provided to receive fuel delivered by a fuel pump, to suck the fuel evaporation gas from the canister through the recovery line and the recovery port upon generation of negative pressure, and to discharge the fuel evaporation gas to the fuel tank, a driving fluid hose connecting the discharge port of the fuel pump to the driving inlet of the ejector to supply the fuel to the ejector, and a recovery control valve for opening and closing a fuel passage so that the fuel is selectively supplied to the ejector.

Methods and systems for purging fuel vapors from an evaporative emissions system of a vehicle are described. The methods and systems may include opening one or more bypass valves of carbon filled canisters to supply air to a low pressure port of a venturi pump. The bypass valves may be opened when fuel vapors are being moved from a fuel tank to an engine while the engine operates.

A vapor canister for a vehicle evaporative emissions control system comprises a canister housing defining an internal volume for receiving therein one or more volumes of adsorbent; a fuel vapor inlet port for connecting the canister to a fuel tank; a vent port for intake of fresh air into the canister; a purge port for withdrawing fuel vapors from the canister; and a pump integrated with the canister housing. The integrated pump is actuated to provide an overpressure or underpressure in the canister. The integrated pump can be used for various operating modes, such as e.g. canister purging, leak detection diagnostic, refueling or engine shut down.

A fuel system comprising a fuel tank, a mixing volume configured to mix fuel vapor and air, the mixing volume comprising an outlet configured to be fluidly coupled to an engine, and a fuel vapor line configured to fluidly couple the fuel tank to the mixing volume.

Methods and systems for determining pressure changes across at least two fuel vapor storage canisters are described. The methods and systems may include determining the pressure changes via a sole pressure sensor. In one example, fuel vapor canister bypass passages are provided to determine pressure values at a plurality of positions within an evaporative emissions system.

The present description provides low DBL bleed emission performance properties that allows the design of evaporative fuel emission control systems that are simpler and more compact than those possible by prior art by inclusion of a vent-side volume comprising a parallel passage adsorbent such as a carbon honeycomb with narrow channel width and low cell pitch.

Methods and systems are presented for operating a refueling valve of an evaporative emissions system. The methods and systems may attempt to reactivate a refueling valve that has stuck due to the refueling valve being exposed to liquid fuel. In one example, a voltage that is applied to the refueling valve may be increased to reactivate the refueling valve.