Systems and methods for diagnosing individual components of an evaporative emissions system are presented. In one example, fuel vapor flow may be a basis for determining whether or not selected emission system components may be degraded. Further, fuel tank pressure may be another basis for determining component whether or not selected emissions system components may be degraded.

A controller for an internal combustion engine is provided. The engine includes a compressor, a three way catalyst, a canister, an evaporated fuel passage, an ejector, and a purge control valve. The controller includes an ECU. The ECU is configured to decrease an opening degree of the purge control valve in response to an increase in pressure on the downstream side of the compressor in a lean supercharging range. The is a range in which an operation air-fuel ratio of the internal combustion engine is leaner than a theoretical air-fuel ratio of the internal combustion engine, and in which the pressure on the downstream side of the compressor is higher than pressure on the upstream side of the compressor.

A vapor purge system for an engine, includes a purge valve having a housing including an input port in communication with a purge canister and including an output port in communication with an intake system component defining a first bore portion receiving the output port with a first seal member disposed therebetween. The intake system component includes a second bore portion receiving a housing portion of the purge valve with a second seal member disposed therebetween. The first and second seal members are spaced such that when the housing is pulled away from the intake system component and the first seal member is out of engagement between the first bore and the output port, the second seal member can remain in engagement so that a diagnostic module can diagnose detachment of the purge valve from the intake system before any hydrocarbon vapor can be released into the atmosphere.

A first fuel storage portion is disposed on the upstream side of a fuel supply device of an engine so as to be contiguous with an air-intake passage of the fuel supply device. A blow-back suppression plate for suppressing blow-back from the air-intake passage is disposed between a filter element and the first fuel storage portion of an air cleaner. A suction-back passage is formed such that fuel accumulated in a fuel accumulation portion in the air cleaner is suctioned back through the suction-back passage into the air-intake passage. The suction-back passage allows communication between the fuel accumulation portion in the air cleaner and a suction-back port formed at the downstream-side end of the first fuel storage portion.

A first fuel storage portion is disposed on the upstream side of a fuel supply device of an engine so as to be contiguous with an air-intake passage of the fuel supply device. A blow-back suppression plate for suppressing blow-back from the air-intake passage is disposed between a filter element and the first fuel storage portion of an air cleaner. A suction-back passage is formed such that fuel accumulated in a fuel accumulation portion in the air cleaner is suctioned back through the suction-back passage into the air-intake passage. The suction-back passage allows communication between the fuel accumulation portion in the air cleaner and a suction-back port formed at the downstream-side end of the first fuel storage portion.

A method for small leak testing of an evaporative emissions system includes monitoring a vacuum pressure level of the evaporation emissions system with the engine on and actuating a canister vent valve to regulate the vacuum pressure level to a predetermined minimum vacuum pressure level. Upon turning the engine off, the canister vent valve and a canister purge valve are closed to seal the evaporative emissions system. Next, the vacuum pressure level is recorded over a predetermined time period after turning off the engine and a fault code is set when the vacuum pressure level becomes less than the predetermined minimum vacuum pressure level.

An apparatus for reducing fuel evaporation gas using a closeable path structure, which is configured such that a path through which fuel evaporation gas can flow is narrowed when an engine stops, may include an intake pipe through which air is drawn into the engine, and an openable door disposed to open or close the intake pipe and configured such that, when the engine is operated, the openable door opens the intake pipe, and when the engine is stopped, the openable door closes the intake pipe, wherein a fuel evaporation gas trap configured to collect the fuel evaporation gas may be disposed on an internal wall of a portion of the intake pipe on which the openable door is disposed.

An apparatus for reducing fuel evaporation gas using a closeable path structure, which is configured such that a path through which fuel evaporation gas can flow is narrowed when an engine stops, may include an intake pipe through which air is drawn into the engine, and an openable door disposed to open or close the intake pipe and configured such that, when the engine is operated, the openable door opens the intake pipe, and when the engine is stopped, the openable door closes the intake pipe, wherein a fuel evaporation gas trap configured to collect the fuel evaporation gas may be disposed on an internal wall of a portion of the intake pipe on which the openable door is disposed.

A purge valve and a fuel vapor management system for use with an engine emission control system are disclosed. The purge valve may include a first inlet for receiving a first flow of air from an air cleaner, a second inlet for receiving a second flow of purge vapors from an evaporative canister, and an outlet directing a controlled mixture of the first and second flows to an engine, upstream of an intake throttle. Relative amounts of the first flow and second flow may be selectively controlled by varying a position of the valve.

Methods and systems are provided for a vapor canister couple to a fuel tank of a vehicle. A series of fluidically coupled, variable capacity bleed elements, externally coupled to a sidewall of the vapor canister, capture the bleed emissions resulting from desorption of fuel vapors from an adsorbent material inside the vapor canister. The series of bleed elements may be fluidically coupled through flow paths passing through the vapor canister wall, connecting through a first flow path to a chamber inside the vapor canister and connecting through a second flow path to a vent port of the vapor canister.