A purge control unit opens the purge control valve to supply, as purge gas to an intake passage, the evaporative fuel together with air in response to a predetermined purge request. An air-fuel ratio detection unit detects an air-fuel ratio of the internal combustion engine. A concentration learning unit estimates a fuel concentration in the purge gas based on a change in the air-fuel ratio when the purge control unit causes the purge gas to be supplied to the intake passage and to perform a fuel concentration learning to update a concentration learning value, which is a learning value of the fuel concentration in the purge gas, based on the estimated fuel concentration. An injection control unit corrects a fuel injection amount based on the concentration learning value in a period in which the concentration learning unit performs the fuel concentration learning in the lean combustion operation.

A canister includes a casing defining an adsorbent chamber. The casing includes a tank port in fluid communication with a fuel tank and an atmospheric port in fluid communication with the atmosphere. The canister includes at least three adsorbent sections arranged in series in the adsorbent chamber. The at least three adsorbent sections include a first adsorbent section proximate to the atmospheric port, a second adsorbent section disposed on a tank port side of the first adsorbent section, and a third adsorbent section disposed on a tank port side of the second adsorbent section. The first adsorbent section contains a first adsorbent, the second adsorbent section contains a second adsorbent, and the third adsorbent section contains a third adsorbent. An adsorption capacity of the first adsorbent is equal to or greater than an adsorption capacity of the second adsorbent. The adsorption capacity of the second adsorbent is greater than an adsorption capacity of the third adsorbent.

An evaporative emission control canister system comprises an initial adsorbent volume having an effective incremental adsorption capacity at 25° C. of greater than 35 grams n-butane/L between vapor concentration of 5 vol % and 50 vol % n-butane, and at least one subsequent adsorbent volume having an effective incremental adsorption capacity at 25° C. of less than 35 grams n-butane/L between vapor concentration of 5 vol % and 50 vol % n-butane, an effective butane working capacity (BWC) of less than 3 g/dL, and a g-total BWC of between 2 grams and 6 grams. The evaporative emission control canister system has a two-day diurnal breathing loss (DBL) emissions of no more than 20 mg at no more than 210 liters of purge applied after the 40 g/hr butane loading step.

Methods and systems are provided for routing secondary air to engine an exhaust system during a cold-start condition to reduce tail pipe emissions. In one example, a method may include operating a pump of an evaporative leak check module (ELCM) in a positive pressure mode and routing pressurized air to the exhaust passage upstream of an exhaust catalyst via an air conduit housing a first valve.

A vapor fuel processing includes a canister for absorbing vapor fuel, a purge pipe, a purge control valve, a pump, a pressure sensor, and a determination unit. The pump may be provided on the purge pipe upstream of the purge control valve. The pressure sensor may be provided between the purge control valve and the pump. The determination unit may determine a state of a purge path by comparing a first detected value of the pressure sensor detected when the pump is driven with the purge control valve in a cutoff state with a first reference value and then comparing a second detected value of the pressure sensor detected when the pump is driven with the purge control valve in the communicated state with a second reference value.

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.

Systems and methods for regenerating a canister purge valve filter that is included in an evaporative emissions system are disclosed. In one example, pressurized air is applied to a canister purge valve filter to dislodge contaminants from the filter. The contaminants may be discharged from the evaporative emissions system via a check valve that opens in response to the pressurized air.

Systems and methods for waking a controller from a sleep mode are described. In one example, the controller may be woke in response to an estimated amount of time that it will take for a temperature in an evaporative emissions system to be within a threshold temperature of ambient temperature.

A fuel vapor storage canister including an integral fuel trap is provided. The fuel trap includes bifurcated chambers with the dual purpose of trapping liquid trace and attenuating noise entering the canister shell and tank line. The upper chamber includes a baffle to block and collect liquid trace, the liquid trace falling through an opening in a partition for collection in a fuel trace collector. The fuel trace collector is suitably positioned within the lower chamber, immediately beneath the opening, and includes a cavity and a venturi. The venturi creates a region of low pressure during purging, which evacuates the cavity by suction. The cavity optionally includes an activated carbon billet, which maintains the pressure level in the fuel vapor line above a predetermined minimum value and which aids in converting the liquid trace to fuel vapor as well as in further attenuating noise escaping into the tank line.

A fuel vapor emissions control device includes: —an absorbent filter; —a purge circuit including: a pump equipped with an intake and with a delivery outlet; an upstream duct; and a downstream duct. The pump includes an intake chamber into which the intake opens. The upstream duct is connected by one of its ends to the absorbent filter and via the other of its ends opens into the intake chamber. The downstream duct includes a double tubular wall defining two separate conduits.