Methods and systems are provided for an evaporative emissions control system for onboard refueling vapor recovery of a heavy duty vehicle. In one example, a method may include adjusting flow among at least two canisters during canister purging, where the at least two canisters are arranged in a parallel loading and unloading flow direction, to increase flow through a higher loaded canister. Flow may be adjusted using a first valve coupled to the first canister, a second valve coupled to the second canister, and so on for n number of canisters and n number of valves, and a balancing valve used to selectively couple the at least two canisters to a fuel tank.

An apparatus is provided for purging fuel evaporation gas in a fuel system. The apparatus increases an amount of fuel evaporation gas that is desorbed from a canister during driving of an engine, and thus prevents fuel evaporation gas adsorbed to the canister from being discharged to the atmosphere.

An isolation valve includes: a housing including a first passage and a second passage; a main valve assembly including a valve disposed in the housing such that a fluid flow between the first passage and the second passage is blocked; a locking assembly disposed in the housing, and including a release element configured to open the valve and a locking element configured to close the valve; and a bobbin assembly configured to be disposed in the housing and to operate the locking assembly, and including a coil; a core disposed inside the coil and including a space therein, the space including a closed end and an opened end; and a plunger configured to move in the space by an electromagnetic force generated by the coil and to contact the locking assembly on the opened end side.

A vehicle and a fuel system for a vehicle are provided. The fuel system has a fuel tank, a fuel fill inlet fluidly connected to the fuel tank to receive fuel dispensed from an external fuel supply device, and a recirculation line with a first end fluidly connected to the fuel fill inlet and a second end fluidly connected to the fuel tank. An ejector is positioned within the recirculation line. A valve fluidly connects the ejector to the fuel tank via a drain line. A method of fueling a vehicle is also provided.

A failure diagnostic device is configured to determine saturated vapor pressures of a fuel within a fuel tank. In a fuel vapor processing apparatus, some or all of the passages and spaces into which the fuel vapor flows into the fuel vapor processing apparatus are closed to the atmosphere. In this condition, the failure diagnostic device determines a plurality of saturated vapor pressure characteristics over time. The failure diagnostic device is configured to diagnose whether or not a leakage or a blockage failure in the fuel vapor processing apparatus is present. The failure diagnostic device determines a Reid vapor pressure (RVP) based on each of the plurality of determined saturated fuel vapor pressure characteristic and diagnoses whether or not a failure is present in accordance with a change in these RVPs over time.

A vehicle includes an engine, a fuel tank, a canister, a valve, and a damper. The canister is configured to receive and store evaporated fuel from the fuel tank. The valve is disposed between the canister and the engine. The valve is configured to open to deliver evaporated fuel from the canister to the engine. The valve is configured to close to inhibit delivering evaporated fuel from the canister to the engine. The damper is secured to valve. The damper is configured to dampen movement of the valve between open and closed positions.

An air filter device includes an air filter and a filter case having a filter housing for housing the air filter. The filter case has a pipe part enclosing an outer circumference of a second end of a filler pipe. The second end of the filler pipe defines a fuel filler opening and is opposite to a first end of the filler pipe connected to a fuel tank of a vehicle. A distance between the pipe part and the fuel filler opening is less than a distance between the filter housing and the fuel filler opening. The pipe part is configured to be inserted into a fixed member fixed to a vehicle body. The pipe part has a flange that extends radially outward from the pipe part and is spaced apart from the filter housing in an axial direction.

A vehicle includes a fuel tank and an evaporative-emissions system having a primary subsystem and an auxiliary subsystem. The primary subsystem has a fuel-vapor canister in fluid communication with the fuel tank to capture fuel vapors of the fuel tank. The auxiliary subsystem is configured to capture fuel vapors associated with an external fuel-storage device. The auxiliary subsystem has an auxiliary port located on an exterior of the vehicle and is configured to connect with the external fuel-storage device. The auxiliary port is selectively connected in fluid communication with the fuel-vapor canister by a valve.

Methods and systems are provided for diagnosing potential degradation of a fuel tank pressure sensor. In one example, a method may include, in response to an ambient pressure reading by the fuel tank pressure sensor during an evaporative emissions (EVAP) system diagnostic, applying vacuum to the EVAP system and indicating degradation of the fuel tank pressure sensor if the canister undergoes an endothermic reaction. If the fuel tank pressure sensor is determined to not be degraded, the method further includes distinguishing between the ambient pressure reading being caused by a leak in the EVAP system and a canister purge valve being stuck closed.

A fault diagnosis method is provided for an evaporated fuel processing device including a canister including a charge port connected to an upper space of a fuel tank, a purge passage connecting a purge port of the canister and an intake system, and including a purge control valve, a drain passage including a drain cut valve, and a pressure sensor. The pressure sensor is configured to sense, as a purge passage pressure, a pressure between the purge control valve and the canister in the purge passage. The fault diagnosis method includes performing a purge by opening the purge control valve in a state in which the drain cut valve is controlled to be opened; measuring an actual pressure variation by the pressure sensor; and diagnosing a closing fixation of the drain cut valve by comparing a predetermined pressure variation and the actual pressure variation.