Design Considerations and Characterization Test Methods for Activated Carbon Foam Hydrocarbon Traps in Automotive Air Induction Systems

摘要

As OEMs race to build their sales fleets to meet ever more stringent California Air Resources Board (CARB) mobile source evaporative emissions requirements, new technologies are emerging to control pollution. Evaporative emissions emanating from sources upstream in the induction flow and venting through the ducts of the engine air induction system (EIS) need to be controlled in order classify a salable vehicle as a Partial Zero Emissions Vehicle (PZEV) in the state of California. As other states explore adopting California's pollution control standards, demand for emissions control measures in the induction system is expected to increase. This paper documents some of the considerations of designing an adsorbent evaporative emissions device in to a 2007 production passenger car for the North American and Asian markets. This new evaporative emissions device will be permanently installed in the vehicle's air cleaner cover without requiring service for 150K miles (expected vehicle life). Addressed are many of the questions and concerns associated with integrating emissions control technology into the EIS. Testing techniques for characterizing the emissions control functions of hydrocarbon traps are discussed in detail. This paper also illustrates and discusses the need to write a uniform and accepted test standard for EIS-based emissions technology. This effort is currently being pursued at the SAE and ISO working groups.