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.

Methods and systems are provided for diagnosing degradation and/or alteration in an evaporative emission control system of a vehicle. In one example, a method for a vehicle may comprise, during a refueling event, detecting presence or absence of a fuel vapor canister coupled to a vent line of the evaporative emission control system of the vehicle based on a response of a hydrocarbon sensor coupled to the vent line. In this way, hydrocarbon emissions may be reduced by identifying vehicles with tampered or degraded evaporative emission control system.

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 coated substrate (2a, 2b) adapted for hydrocarbon adsorption having at least one surface, and a coating on the at least one surface, the coating comprising particulate carbon and a binder, wherein the particulate carbon has a BET surface area of at least about 1300 m.sup.2/g; and at least one of: (i) a butane affinity of greater than 60% at 5% butane; (ii) a butane affinity of greater than 35% at 0.5% butane; (iii) a micropore volume greater than about 0.2 ml/g and a mesopore volume greater than about 0.5 ml/g. A bleed emission scrubber (1) and an evaporative emission control canister system (30) comprising the coated substrate (2a, 2b) are provided. They can control evaporative hydrocarbon emissions and may provide low diurnal breathing loss (DBL) emissions even under a low purge condition.

A canister, mounted in a vehicle with an engine and including one or more chambers, includes adsorbents, an inflow port, an atmosphere port, an outflow port, two or more adjusting portions, and one or more coupling portions. The two or more adjusting portions are elongated members placed in at least one target chamber of one or more chamber togethers, together with corresponding one adsorbent among the adsorbents to the target chamber. The one or more coupling portions couple the two or more adjusting portions to one another. Furthermore, the one or more coupling portions are provided to the two or more adjusting portions at a position distanced from end surfaces of the two or more adjusting portions.

A method for improving accuracy of correction of fuel quantity at the time when a recirculation valve (RCV) is opened, may include a step of correcting injection amount of fuel based on consideration factors when the RCV is operated to be opened. The consideration factors include property values of a flow path of the RCV, the flow path being mounted to an intake pipe to connect between a front end of a compressor close to the atmosphere and a rear end of the compressor adjacent to combustion chambers, a first calculation value obtained by calculating amount of air to be introduced into the combustion chambers after circulating from the flow path of the RCV to the intake pipe, and a second calculation value obtained by calculating amount of hydrocarbon to be introduced into the flow path of the RCV by purging evaporative gas.

A sorption device for filtering evaporation emissions from a fuel tank, includes a vessel, with a first opening connected to an air removal path of the fuel tank and a second opening opening to atmosphere, a middle annular space between a radial outer circumferential boundary of the middle annular space and a radial inner circumferential boundary thereof radially inwardly spaced apart from the outer boundary, a first annular space formed between a radial inner surface of a fluid-tight circumferential outer shell of the vessel, the radial outer boundary being radially inwardly spaced from the inner surface, a sorbent material arranged in the middle annular space, and evaporation emissions from the fuel tank are guided through the first opening into the first annular space, through the sorbent material into a central space of the vessel in the radial direction, and through the second opening to atmosphere or another sorption device.

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.

An evaporated fuel treatment device includes a main adsorption chamber and a sub adsorption chamber. The sub adsorption chamber includes a first adsorption layer, a second adsorption layer and a high-desorption layer. The second adsorption layer is situated closer to an atmosphere port than the first adsorption layer is, and has a lower performance of adsorbing fuel vapor than the first adsorption layer does. The high-desorption layer is situated closer to the main adsorption chamber than the first adsorption layer is, and a higher performance of desorbing the fuel vapor than the first adsorption layer or the second adsorption layer does.