In a fuel vapor treatment apparatus, when an internal combustion engine is in non-turbocharging operation, a controller is configured to open a first valve and a second valve, and when the internal combustion engine is in turbocharging operation, the controller is configured to close the first valve, and to open a third valve based on pressure in a fuel tank detected by a first pressure detector.

The evaporated fuel processing device may include a pump unit including a pump body configured to pump out evaporated fuel generated in a fuel tank to an intake passage, and a pump controller configured to drive the pump body; and a controller configured to cause the pump controller to control the pump body. When an index related to a temperature of the pump unit exceeds a predetermined range, the controller may restrict the driving of the pump body.

A fuel supply system for propane and other LPG fuels is disclosed for internal combustion engines such as spark-ignited direct-injection (SIDI) engines, with features that help manage both liquid and gaseous phases of the LPG fuel. Preferably adapted for use with replaceable fuel canisters, the ECM-managed system has a hot-soak vapor purge system as well as various sensors and valves to prevent excessive boil-off and to otherwise manage the heat and the related liquid-vapor balance of the fuel supply. Although various control strategies are contemplated in different respects, the system preferably uses an intermediate pressure vessel in which the amount of gravity-fed liquid LPG is monitored using a float sensor or the equivalent, and the system is programmed to intervene through valve controls to vent excessively hot LPG vapors from the pressure vessel directly to the engine's intake manifold as a way of managing the heat and liquid-vapor balance in the pressure vessel, accommodating the vented flow by blending the vented fuel vapors with fuel from liquid rail injectors to still produce the desired overall mass flow rate of the fuel to produce the appropriate power levels from the engine.

Methods and systems are provided for determining an offset of a pressure sensor that is used for monitoring pressure in a fuel system that is sealed expect for refueling and other diagnostic events. In one example, a method includes waking a controller of a vehicle when it is expected that a pressure in a fuel system that is sealed from atmospheric pressure is at atmospheric pressure, unsealing the fuel system, and indicating an offset of the pressure sensor based on a pressure change after the fuel system is unsealed. In this way, pressure sensor offset may be determined regularly without undesirably loading a fuel vapor storage canister with vapors, which may be particularly advantageous for hybrid vehicles.

An evaporated fuel processing device including a pump sending a purge gas from a canister to an intake passage, a control valve switching between a communication state and a cutoff state where the canister and the intake passage are cut off on the purge passage, a return flow passage having one end connected to the purge passage between the pump and the control valve, and other end connected to an upstream side of the pump, wherein the purge gas flows from the one end to the other end in a case where the pump is activated in the cutoff state of the control valve, and a detecting device specifying an evaporated fuel concentration in the return flow passage during the cutoff state of the control valve in a case where the control valve is controlled based on the duty ratio and the pump is activated.

Methods and systems are provided for refilling a fuel tank devoid of fuel vapors. In one example, a method may include, prior to an upcoming refueling event, conditioning a fuel vapor-less fuel tank by operating a fuel pump. Operation of the fuel pump may agitate and vaporize the residual fuel in the fuel tank.

An engine off natural vacuum (EONV) evaporative fuel leak check system includes a fuel tank, a heat exchanger, an air duct, a fan, a fuel temperature sensor, and a controller. The fan directs air onto the heat exchanger, and the heat exchanger heats air passing around the heat exchanger in a heat exchange process using heat from engine coolant within the heat exchanger. The air duct extends between the fuel tank and the heat exchanger and the fan moves the heated air through the air duct toward the fuel tank. The controller is configured to control the fan for moving the heated air toward the fuel tank based on a temperature of the fuel within the fuel tank, as detected by the fuel temperature sensor.

An evaporated fuel processing device that includes a pump configured to supply purge gas, which includes evaporated fuel in a fuel tank, to an intake passage of an engine through a purge passage; a controller configured to control the pump; and a detecting unit configured to acquire a gas amount introduced to the intake passage while the pump is being driven in a stable state where an air amount introduced from open air to the intake passage is stable, and configured to detect, by using change in the acquired gas amount, a state where the purge gas is unable to be normally supplied from the purge passage to the intake passage.

When high-pressure purge (the first purge control) (d-f) in which fuel evaporative gas in the fuel tank is emitted until internal pressure in the fuel tank decreases to a second predetermined pressure by closing a vapor solenoid valve, opening a fuel tank shutoff valve and a purge control valve when an engine is running finishes, connecting passage purge (the second purge control) (f-g) in which the fuel evaporative gas in vapor piping and purge piping is emitted up to a second predetermined volume (a second predetermined value) or above is performed, and then the fuel evaporative gas in a canister is emitted by opening the vapor solenoid valve (the third purge control) (g-h).

A pump assembly for a liquid trap of a vehicle fuel tank assembly includes a pump configured to couple to the liquid trap and selectively drain liquid therefrom, a sensor configured to monitor an inductive signature of the pump, and a controller programmed to operate the pump and monitor the inductive signature to determine if liquid is present in the liquid trap based on the monitored inductive signature.