Methods and systems are provided for diagnosing degradation and/or alteration in an evaporative emission control system of a vehicle. In one example, a method may include, during a refueling, monitoring a fuel tank pressure and a fuel fill level, and detecting a presence or an absence of a fuel vapor canister of the EVAP system based on a change in fuel tank pressure with an increase in fuel level.

Methods and systems for diagnosing operational status of a carbon filled canister heater are described. The methods and systems may include activating an evaporative emissions system heater, a pump, and a canister purge valve to determine if long chain hydrocarbons are released from a carbon filled canister. Release of long chain hydrocarbons from the carbon filled canister may be indicative of desired operation of a carbon filled canister heater.

A cylindrical column-shaped honeycomb adsorbent has a plurality of cell passages extending along an axial direction of the honeycomb adsorbent. The plurality of cell passages are configured so that a pitch of adjacent cell passages is within a range of 1.5 mm˜1.8 mm, and so that a thickness of a wall between the cell passages is within a range of 0.45 mm˜0.60 mm. With this configuration, the honeycomb adsorbent exhibits BWC (Butane Working Capacity) of 6.5 g/dL or greater. By mixing fibrous meltable core melting away during baking, the honeycomb adsorbent has macropores configured to have a volume of 0.15 mL/g˜0.35 mL/g with respect to an overall weight of the honeycomb adsorbent and metal oxide particles having a proportion of weight of 150˜250% with respect to the activated carbon.

A hybrid vehicle includes a canister that adsorbs evaporative fuel generated in the fuel tank for an internal combustion engine. The hybrid vehicle can drive a drive wheel even when the internal combustion engine is stopped. When the internal combustion engine of the hybrid vehicle is stopped and a prescribed set of conditions is satisfied, the internal combustion engine is rotated by the generator. When the internal combustion engine of the hybrid vehicle is rotated by the generator, the evaporative fuel adsorbed in the canister is supplied to the upstream side of an upstream side exhaust catalytic converter device. In the hybrid vehicle, the introduced evaporative fuel as reducing agent is adsorbed in the upstream side exhaust catalytic converter device and a downstream side exhaust catalytic converter device.

A vehicle includes an engine, a fuel tank, a primary canister, a buffer canister, a purge valve, a check valve, and a controller. The fuel tank is configured to store fuel. The primary canister is configured to receive and store evaporated fuel from the fuel tank. The buffer canister is configured to receive and store the evaporated fuel from the fuel tank. The buffer canister is disposed between the primary canister and the engine. The purge valve is disposed between the buffer canister and the engine. The purge valve is configured to direct the evaporated fuel from the primary and buffer canisters to the engine when open. The check valve is disposed between the primary and buffer canisters and is configured to restrict backflow of the evaporated fuel from the buffer canister toward the primary canister. The controller is programmed to diagnose the operability of the check valve.

A fuel tank system includes a fuel storage unit, a processing unit, and a control unit. The control unit performs a first failure diagnosis of diagnosing a failure of the fuel storage unit in a state where the sealing valve is closed. When the control unit diagnoses that the fuel storage unit is normal, the control unit performs a second failure diagnosis of diagnosing a failure of a purge valve and a bypass valve by causing a pressure generation unit to generate pressure in a state where the sealing valve is closed. When there is a possibility that the purge valve and the bypass valve are in closed-sticking, the control unit performs a third failure diagnosis of specifying a failure in any one of closed-sticking of the purge valve and closed-sticking of the bypass valve by opening the sealing valve.

A fuel tank system constructed in accordance to one example of the present disclosure includes a fuel tank and an evaporative emissions control system. The evaporative emissions control system is configured to recapture and recycle emitted fuel vapor. The evaporative emissions control system includes a liquid trap, a first device, a second device, a control module and a G-sensor. The first device is configured to selectively open and close a first vent. The second device is configured to selectively open and close a second vent. The control module regulates operation of the first and second devices to provide over-pressure and vacuum relief for the fuel tank. The G-sensor provides a signal to the control module based on a measured acceleration.

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.

A system for testing an evaporative emissions (EVAP) canister of a vehicle according to the present disclosure includes an evaporator configured to contain liquid fuel, a fuel vapor supply line configured to deliver a mixture of fuel vapor and carrier gas from the evaporator to the EVAP canister, and a fuel vapor supply valve disposed in the fuel vapor supply line. The test system further includes a gas density meter configured to measure a density of the fuel vapor mixture flowing through the fuel vapor supply line, and a valve control module configured to control a position of the fuel vapor supply valve to adjust a flow of fuel vapor from the evaporator to the EVAP canister based on the fuel vapor mixture density.

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.