Air Intake System Evaporation Emissions: Physical Description and Solutions

摘要

Reducing evaporation emission is one of the most important targets during vehicle development nowadays. Apart from the emissions while the vehicle is in operation, evaporation emissions occur after the engine is turned off. Up to 30% of these emissions can originate from the Air Intake System (AIS). Today, Hydro Carbon Adsorbers (HCA) are already used as a part of the AIS to reduce evaporation emissions. Usually the HCA contains activated carbon or zeolite. HC emissions are adsorbed by the HCA during and after the engine shut down. When the engine is running, the HCA is purged with the intake air. The HC storage principle is well known for carbon canisters.