Methods and systems are provided for reducing a possibility of hydrocarbon (HC) breakthrough during a diagnostic routine of an evaporative emissions control (EVAP) system. In one example, a method may include, during the diagnostic routine, switching a direction of air-flow through a fuel vapor canister via adjustments to a three-way valve in response to a higher than threshold a change in temperature within the canister.

Provided is an evaporated fuel treatment device configured to adsorb and desorb an evaporated fuel originating in a fuel tank. A first adsorption chamber is arranged in a flow passage. A second adsorption chamber is connected to the first adsorption chamber, and is arranged, in the flow passage, closer to an atmosphere port with respect to the first adsorption chamber. A first adsorption layer is arranged within the first adsorption chamber, and adsorbs the evaporated fuel. A second adsorption layer is arranged within the second adsorption chamber, and adsorbs the evaporated fuel. A sectional area of the second adsorption layer perpendicular to a direction in which the evaporated fuel flows through the second adsorption layer being larger than a sectional area of the first adsorption layer perpendicular to a direction in which the evaporated fuel flows through the first adsorption layer.

A combined mass airflow sensor and hydrocarbon trap is provided for absorbing evaporative hydrocarbon emissions from an air intake duct of an internal combustion engine. The combined mass airflow sensor and hydrocarbon trap comprises a duct that supports a hydrocarbon absorbing sheet in an unfolded configuration within a housing. The duct communicates an airstream from an air filter to the air intake duct during operation of the internal combustion engine. An opening in the housing receives a mass airflow sensor into the duct, such that the mass airflow sensor is disposed within the airstream. Guide vanes extending across the duct reduce air turbulence within the airstream passing by the mass airflow sensor. Ports disposed along the duct allow the evaporative hydrocarbon emissions to be drawn into the interior and arrested by the hydrocarbon absorbing sheet when the internal combustion engine is not operating.

The present disclosure relates to hydrocarbon emission control systems. More specifically, the present disclosure relates to substrates coated with hydrocarbon adsorptive coating compositions and evaporative emission control systems for controlling evaporative emissions of hydrocarbons from motor vehicle engines and fuel systems. The hydrocarbon adsorptive coating compositions include particulate carbon having 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 mug and a mesopore volume greater than about 0.5 ml/g.

Methods and systems are provided for indication of a degradation in an EVAP and/or fuel system. In one example, a method for indication of a presence or absence of a degradation in a refueling system may include vacuum pull-down and pressure bleed-up tests being carried out based on a state of submersion of a spud valve in liquid fuel in a fuel tank.

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, and an adjusting member. The adjusting member is placed in a target chamber of the two or more chambers together with a corresponding adsorbent of the adsorbents. The target chamber is provided with a cushioning area located adjacent to at least one port of the ports. Two or more rod-shaped portions have first and second cross-sections orthogonal to a flow direction of an atmosphere and a fuel vapor. The first cross section is formed in the cushioning area, and the second cross-section is formed at a position distanced from the at least one port relative to the cushioning area. The first cross-section has a smaller area than an area of the second cross-section.

The present disclosure describes an evaporative emission control canister system that includes: one or more canisters comprising at least one vent-side particulate adsorbent volume comprising a particulate adsorbent having microscopic pores with a diameter of less than about 100 nm; macroscopic pores having a diameter of about 100 - 100,000 nm; and a ratio of a volume of the macroscopic pores to a volume of the microscopic pores that is greater than about 150%, and having a retentivity of about 1.0 g/dL or less. The system may further include a high butane working capacity adsorbent. The disclosure also describes a method for reducing emissions in an evaporative emission control system.

Methods and systems for diagnosing operation of an evaporative emissions system are described. The methods and systems may include increasing an amount of vacuum stored in an evaporative emissions system during discontinuously operating an engine in a boosted operating mode. Storing vacuum allows the evaporative emissions system to reach a desired vacuum level to verify absence of an evaporative emissions system breech.

A control unit diagnoses a failure of a fuel storage unit that seals a fuel tank and a processing unit that processes fuel evaporative gas in the fuel tank. A first pressure detection unit of the fuel storage unit detects the pressure of the fuel tank. A second pressure detection unit of the fuel storage unit is disposed at a position different from the first pressure detection unit, and detects the pressure of the fuel tank. The control unit specifies a failure portion of the fuel storage unit and the processing unit based on a change in either one or both of a first pressure value detected by the first pressure detection unit and a second pressure value detected by the second pressure detection unit when the pressure of the fuel tank is changed.

A method and device for diagnosing a leak in an evaporation system and in a tank ventilation line of an internal combustion engine is disclosed. The method includes diagnosing the entire evaporation system using a fresh-air shut-off valve of the evaporation system and a pressure sensor system of the evaporation system. During the check on whether there is a leak in the evaporation system of the internal combustion engine, a separate check of different diagnosis regions of the evaporation system is undertaken, where one of these diagnosis regions is a tank region of the internal combustion engine and a further diagnosis region is a filter region of the internal combustion engine. During the diagnosis of the tank ventilation line, the flow through the tank ventilation line is checked.