EVAPORATIVE FUEL VAPOR EMISSION CONTROL SYSTEMS

摘要

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. 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 BETP butane loading step.