Hydrocarbon emission filter system vehicle fuel tanks - has additional filler contg. active carbon@, porous polymer etc. for reducing desorbed hydrocarbon concn. peak

摘要

In a filter system for preventing hydrocarbon emission from vehcicles with OTTO engines, having an adsorption filter (F1) which, during travel, is desorbed in counter-current by the engine intake air, the novelty is that the hydrocarbon concn. peak, occurring on desorption, is reduced by a succeeding adsorption filter (F2). The adsorbent may be active carbon, a porous polymer (esp. based styrene/divinyl benzene) or a hydrophobic zeolite and may be adhesively bonded pref. to a reticulated coarsely porous polyurethane foam matrix. USE/ADVANTAGE - Used to prevent emissions from carburettors and fuel tanks. The additonal adsorption filter provide smoothing of the desorbed hydrocarbon concn., esp. when large (4-5l) filter canisters are used.