Exhaust After-Treatment System With Improved DEF Purge Cycling In Agricultural Vehicles

摘要

An exhaust after-treatment system has a DEF system with improved DEF purge cycling during which time DEF is returned to a DEF storage tank. The DEF system adapts its methodology based on a condition within the DEF system. A purge valve may be arranged in a doser feed line between a DEF supply module and a DEF doser module. A purging control system may be configured to control the purge valve based on detected states within the DEF system, such as a detected state that corresponds to a plugged DEF doser module. If a plugged doser module is detected, the purge valve may be opened to vent the doser module feed line to atmosphere which allows the DEF to be returned to the DEF storage tank without creating a siphon effect that could draw additional DEF from the DEF storage tank into the supply module.