Technical Paper
Development of Leak Tightness Specifications for Automotive Fuel System Components as Required to meet Hydrocarbon Emission Regulations using the Equivalent Channel Concept and its Implementation Method for Production Leak Testing
2010-04-12
2010-01-1104
Determination of appropriate leak tightness specifications for production leak testing of fuel system components has challenged the automotive industry for many years. This process has become more complicated as hydrocarbon emission regulations have been lowered (US-EPA, CARB LEVII, Euro5, etc.). Application of the equivalent channel (EC) concept can significantly simplify the process of determining leak tightness specifications. This paper describes the test procedure and results of a hydrocarbon emission study designed to define a critical geometry (known as Equivalent Channel-EC) that will plug after exposure to gasoline, resulting in no HC emission due to leaks during Vehicle SHED (Sealed Housing for Evaporative Determination) tests. This critical geometry will stop any measurable hydrocarbon leakage after enough time has elapsed for the channel to plug. Micro-channels of several diameters and lengths were tested in a Micro-SHED at 40 degrees Celsius for 24 hours.
