A fuel vapor treatment apparatus is provided with a fuel tank for storing fuel of an internal combustion engine, a canister for adsorbing fuel vapor generated in the fuel tank, a pump for reducing a pressure inside a detection target system including the fuel tank, a pressure detection sensor for detecting the pressure inside the detection target system, and a fluctuation detection unit for detecting a fluctuation width of the pressure inside the detection target system at the time when the pressure inside the detection target system is reduced to a predetermined pressure value.

A fuel tank isolation valve for a vehicle is provided. A valve opening operation or a valve closing operation is performed using guide protrusions configured to move along a guide slot, in response to an upward or downward movement of a plunger. The discharge of a battery is prevented. An abrupt change in the pressure of a fuel tank is prevented.

A fuel tank isolation solenoid valve for a vehicle is provided. The fuel tank isolation solenoid valve may include a first plunger configured to be vertically movable and a second plunger configured to move along a plunger rotation path such that the plunger is mechanically maintained in an opened position or a closed position while no power is applied to a coil.

A vent apparatus is described for providing filtered air intake and rollover protection for a fuel tank. The apparatus may include a housing configured to be coupled with the fuel tank, the housing including at least one air intake port and at least one air exhaust port. The apparatus may include an air intake filter disposed within the housing and configured to receive and filter air from the at least one air intake port. The apparatus may include a rollover protection valve disposed adjacent to the housing and configured to be located inside the fuel tank when the housing is coupled with the fuel tank, the rollover protection valve coupled with the at least one air exhaust port. The rollover protection valve may include a chamber and a plug configured to impede the flow of fuel from the fuel tank into the at least one air exhaust port.

Methods and systems are presented for diagnosing operation of passive grade vent valves of a fuel system. The methods and systems include adjusting a position of a vehicle so that fuel in a fuel tank may cause a first grade vent valve to open and a second grade vent valve to close.

Methods and systems for cleaning a capless refueling system in a vehicle are disclosed. In one example approach, a method comprises, in response to a leak detected following a refueling event, cleaning the capless refueling system using engine vacuum.

A discharge connection, an inlet pipe, an outlet pipe and a drain channel are provided. On an outer end, the outlet pipe has an outwardly closing check valve with a valve body and a valve seat. The outlet pipe has a first coupling geometry at the outer end, which can be interlockingly connected to a conduit coupling. The check valve is designed to be moved from the valve seat into a open position, spaced apart from same, by a profile element projecting into the outer end.

A method is presented, comprising, during a first condition, including an active refueling event, receiving an indication of hydrocarbon breakthrough from the fuel vapor canister; and restricting flow of fuel vapor through a fuel vapor canister vent pathway responsive to the indication of hydrocarbon breakthrough. Restricting the fuel vapor canister vent pathway will cause fuel tank pressure to increase, thus triggering an automatic shutoff of a refueling dispenser. In this way, the refueling event may be terminated without releasing significant quantities of hydrocarbons into the atmosphere.

A fuel-conveying system includes: a primary fuel pump, configured to supply fuel to an internal combustion engine of a vehicle, at a fuel pressure; a suction jet pump configured to convey fuel from a first region of a fuel tank of the vehicle to a second region of the fuel tank, the at least one suction jet pump having a nozzle; and a secondary fuel pump, decoupled from the primary fuel pump and configured to: supply, as required, the suction jet pump with a fuel jet, and set, independently of the primary fuel pump, a pressure of the fuel jet before the nozzle of the suction jet pump.

The mechanical breather valve includes a valve body, on which is installed one-way air inlet and outlet components. A tank, for environmental protection, is fitted with the breather valve and closed so that no volatile gas will be exhausted, when the pressure within is balanced with the outside. When the pressure within is negative, the one-way air inlet hole will draw air from outside to keep the balance of pressure. When the pressure within is increased, one-way air outlet hole will exhaust the additional air. When the tank is tilted or placed upside down, the breather valve can prevent the oil from flowing out of the tank for safe usage.