DUAL PATH PURGE MONITOR USING HYDROCARBON SENSOR TO DIAGNOSE BOOSTED EVAP PURGE PATH
Publication Date: 2014-Jun-11
The IP.com Prior Art Database
Page 01 of 1
DUAL PATH PURGE MONITOR USING HYDROCARBON SENSOR
TO DIAGNOSE BOOSTED EVAP PURGE PATH
Vehicles sold in North America must adsorb fuel vapors in a carbon canister and purge the vapors when engine is combusting. Boosted engines must purge under vacuum or boost conditions. To facilitate purge under boost, new hardware is added to the Evap system (check valves and ejector). Automakers have encountered difficulty in diagnosing the output of ejector in dual path purge systems under boost diagnostic. If the line between ejector and Air Intake System (AIS) is broken, hydrocarbons (HC) will be released to atmosphere. A solution to this was the elimination of the line between ejector and AIS, and directly mounting the ejector by spin welding it onto the AIS. While eliminating the line between ejector and AIS reduces the risk of HC emissions, the ejector can still break at the AIS or assembly plant and/or the service technician may forget to re-install it. If that occurs, hydrocarbons will be released into atmosphere during boosted purge mode without being diagnosed.
This method focuses on detecting HC escaping to the atmosphere.We install a HC sensor at the point just inside the AIS where the ejector meets the AIS system. Whether the ejector is direct mount to AIS or whether a line exists between the ejector and AIS or any other plumbing solution, an HC sensor would affirm that purge vapors are entering the AIS via the ejector path and not escaping into atmosphere....