Methods and systems are provided for diagnosing a heating element coupled to a canister of an evaporative emissions control (EVAP) system. In one example, a method (or system) may include evacuating the canister at different temperature conditions, and diagnosing the heating element based on the different times taken to evacuate the canister at the different temperature conditions.

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.

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 fuel vapor treatment apparatus includes a controller configured to detect an abnormality in at least one of a first check valve, a second check valve, a second purge passage, a charging passage, and an ejector based on pressure detected by a pressure detector.

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.

A flow control valve may include a housing including a fluid-flow channel, a valve seat including a valve hole and positioned in the fluid-flow channel, an electric motor disposed in the housing, and a valve body configured to be axially moved toward and away from the valve seat by the electric motor via a feed screw mechanism. The valve body includes a straight projecting portion. The projecting portion is configured to be positioned in the valve hole in an initial valve body lifting range in which a lift distance of the valve body relative to the valve seat is not greater than a predetermined lift distance.

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.

An evaporated fuel processing device that includes a fuel tank; a vapor passage through which evaporated fuel generated from a fuel in the fuel tank flows; a closing valve configured to open and close the vapor passage; a concentration sensor configured to detect a concentration of the evaporated fuel in the vapor passage downstream of the closing valve; and a controller. When the closing valve moves toward an open side in the closed state, the controller may specify a valve-opening-start position of the closing valve based on a concentration detected by the concentration sensor, wherein the valve-opening-start position is a position where the closing valve transitions from the closed state to the opened state.

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.