A leakage diagnostic device diagnoses leakage of evaporated fuel in an evaporative fuel treatment device. The evaporative fuel treatment device purges evaporated fuel, which is generated in a fuel tank and adsorbed on a canister, to an intake passage. The leakage diagnostic device includes a vent valve that blocks a first atmospheric passage, which connects the canister with an atmospheric opening, and a pump that pressurizes and depressurizes a second atmospheric passage, which is a bypass passage of the first atmospheric passage. The malfunction diagnostic device diagnoses malfunction of the leakage diagnostic device based on an output value of a pressure sensor that detects pressure in a passage connected to the canister.

Methods and systems are provided for reducing a possibility of hydrocarbon (HC) release to atmosphere from an evaporative emissions control (EVAP) system. In one example, a method may include, isolating a fuel vapor canister of the EVAP system from atmosphere and an engine intake manifold upon conditions being met for a potential hydrocarbon (HC) breakthrough from the fuel vapor canister.

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.

Methods and systems are provided for reverse purging of a fuel vapor canister of an engine. In one example, a method may include heating a fuel vapor canister, sealing a fuel tank in order to generate a vacuum in the fuel tank, and in response to the pressure in the fuel tank reaching a target vacuum, initiating reverse purging of the fuel vapor canister.

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.

Disclosed is a device for evaporating vapors of a fuel stored in a motor vehicle tank. The evaporation device includes a bypass circuit and a bypass valve configured to move between a so-called “absorption” position, in which the bypass valve allows the gases to flow between the tank and an absorbent filter and a so-called “leak detection” position, in which the bypass valve allows the gases to flow between a purge circuit and the tank via the bypass circuit.

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.

Provided is a canister that can inhibit discharge of evaporated fuel to the atmosphere. One aspect of the present disclosure is a canister. The canister includes a charge port, a purge port, an atmosphere port, a main chamber to which a charge port and a purge port are connected, a sub chamber to which the atmosphere port is connected, an intermediate chamber arranged between the main chamber and the sub chamber in a flow path of an evaporated fuel, the intermediate chamber being connected to each of the main chamber and the sub chamber, a first adsorbent stored in the main chamber, second adsorbent stored in the sub chamber, and a third adsorbent stored it intermediate chamber. An adsorption capacity of the third adsorbent is smaller than each of an adsorption capacity of the first adsorbent and an adsorption capacity of the second adsorbent.

A fuel system, a vehicle, and a method of controlling an evaporative emissions system for the vehicle are provided. The fuel system has a fuel tank having a fuel fill port with a closure member. An evaporative emissions canister has a first port fluidly coupled to the fuel tank to receive vapor therefrom and a second port, with the canister positioned between an air intake for an engine and a vent to atmosphere. A filter or a second canister is supported by a bracket for movement between first and second positions, with the filter fluidly coupling the second port of the canister to the vent in the first position, and the filter spaced apart from and decoupled from the second port of the canister in the second position. The second port of the canister is in direct fluid communication with atmosphere when the filter is in the second position.