Inverted Exhaust Gas Treatment Injector

An exhaust gas treatment system for reducing emissions from an engine includes an exhaust conduit adapted to supply an exhaust stream from the engine to an exhaust treatment device. The conduit includes an upstream zone, a reduced cross-sectional area zone, and a downstream zone. The upstream and downstream zones are positioned adjacent to and on either side of the reduced cross-sectional area zone. An injector is fixed to the exhaust conduit for injecting a reagent into the exhaust stream at the downstream zone, such that the reagent is injected into the exhaust stream at a venturi effect location of reduced exhaust pressure. The injector is mounted to spray reagent along an injection axis that extends at an angle ranging from 40 to 65 degrees from a longitudinal axis of the conduit.