A purge control unit opens the purge control valve to supply, as purge gas to an intake passage, the evaporative fuel together with air in response to a predetermined purge request. An air-fuel ratio detection unit detects an air-fuel ratio of the internal combustion engine. A concentration learning unit estimates a fuel concentration in the purge gas based on a change in the air-fuel ratio when the purge control unit causes the purge gas to be supplied to the intake passage and to perform a fuel concentration learning to update a concentration learning value, which is a learning value of the fuel concentration in the purge gas, based on the estimated fuel concentration. An injection control unit corrects a fuel injection amount based on the concentration learning value in a period in which the concentration learning unit performs the fuel concentration learning in the lean combustion operation.

A canister includes a casing defining an adsorbent chamber. The casing includes a tank port in fluid communication with a fuel tank and an atmospheric port in fluid communication with the atmosphere. The canister includes at least three adsorbent sections arranged in series in the adsorbent chamber. The at least three adsorbent sections include a first adsorbent section proximate to the atmospheric port, a second adsorbent section disposed on a tank port side of the first adsorbent section, and a third adsorbent section disposed on a tank port side of the second adsorbent section. The first adsorbent section contains a first adsorbent, the second adsorbent section contains a second adsorbent, and the third adsorbent section contains a third adsorbent. An adsorption capacity of the first adsorbent is equal to or greater than an adsorption capacity of the second adsorbent. The adsorption capacity of the second adsorbent is greater than an adsorption capacity of the third adsorbent.

An engine system is provided for an aircraft having an engine and an engine controller. The engine system includes: an electric machine configured to be in electrical communication with the engine controller for powering the engine controller; and a fuel oxygen reduction unit defining a liquid fuel flowpath and a stripping gas flowpath and configured to transfer an oxygen content of a fuel flow through the liquid fuel flowpath to a stripping gas flow through the stripping gas flowpath, the fuel oxygen reduction unit also in electrical communication with the electric machine such that the electric machine powers at least in part the fuel oxygen reduction unit.

An engine system is provided for an aircraft having an engine and an engine controller. The engine system includes: an electric machine configured to be in electrical communication with the engine controller for powering the engine controller; and a fuel oxygen reduction unit defining a liquid fuel flowpath and a stripping gas flowpath and configured to transfer an oxygen content of a fuel flow through the liquid fuel flowpath to a stripping gas flow through the stripping gas flowpath, the fuel oxygen reduction unit also in electrical communication with the electric machine such that the electric machine powers at least in part the fuel oxygen reduction unit.

An evaporated fuel processing device may include a flow passage through which evaporated fuel generated in a fuel tank flows; a first adsorbent constituted of activated carbon and arranged in the flow passage for adsorbing the evaporated fuel flowing in the flow passage; and a second adsorbent constituted of a porous metal complex and arranged in the flow passage on a downstream side of the first adsorbent for adsorbing the evaporated fuel having passed through the first adsorbent and flowing in the flow passage on the downstream side of the first adsorbent.

Methods and systems are provided for conducting vehicle fuel system and/or evaporative emissions system diagnostics, where the diagnostics rely on a positive pressure with respect to atmospheric pressure. In one example, a method comprises activating an electric compressor positioned in an intake of an engine configured to receive purge gasses from the evaporative emissions system under boosted engine operation and natural engine operation, to direct a positive pressure with respect to atmospheric pressure to the fuel system and/or evaporative emission system to conduct said diagnostic. In this way, diagnostics that rely on positive pressure with respect to atmospheric pressure may be conducted in vehicles with a dual-path purge system, without introduction of a pump in the evaporative emissions system.

A purge system for fuel evaporation gas may include an ejector, having a nozzle configured to allow driving fluid to pass therethrough, a driving inlet through which the driving fluid is supplied into the ejector, a suction inlet through which purge gas including a fuel component is drawn as suction fluid from a canister into the ejector, a diffuser outlet through which a mixture of the driving fluid that has passed through the nozzle and the drawn purge gas is discharged out of the ejector, and a suction passage extending from the suction inlet toward a downstream side of the nozzle based on a flow direction of the driving fluid, and a bypass passage coupled from the suction inlet to the driving inlet.

Methods and systems are provided for conducting a diagnostic on a fuel tank isolation valve that regulates a flow of fuel vapors from a fuel tank to an evaporative emissions system. In one example, a method comprises determining whether the fuel tank isolation valve is stuck in a first open position or a second open position based on a time duration between commanding open a canister purge valve to direct fuel vapors to an engine, and an exhaust gas sensor indicating a rich air-fuel ratio. In this way, appropriate mitigating action may be taken in response to the fuel tank isolation valve being stuck in either the first open position or the second open position.

An evaporated fuel processing device that determines whether a normal state is established, by using pressures by a pressure detector while the evaporated fuel processing device shifts between: a first state where a purge passage is opened by a first valve, air passage is opened by a second valve, the purge passage is closed by a third valve, and a pump stops; a second state, after the first state, where the purge passage is opened by the first valve, the air passage is opened by the second valve, the purge passage is closed by the third valve, and the pump is operating; and a third state which takes place after the second state and where the purge passage is opened by the first valve, the air passage is closed by the second valve, the purge passage is closed by the third valve, and the pump stops.

Methods and systems are provided for conducting a diagnostic on a fuel tank isolation valve that regulates a flow of fuel vapors from a fuel tank to an evaporative emissions system. In one example, a method comprises determining whether the fuel tank isolation valve is stuck in a first open position or a second open position based on a time duration between commanding open a canister purge valve to direct fuel vapors to an engine, and an exhaust gas sensor indicating a rich air-fuel ratio. In this way, appropriate mitigating action may be taken in response to the fuel tank isolation valve being stuck in either the first open position or the second open position.