Urea common rail

An exhaust system including a selective catalytic reduction (SCR) component and an oxidation catalyst component. The exhaust system also includes an exhaust treatment fluid injection system for dispersing an exhaust treatment fluid into an exhaust stream at a location adjacent either the SCR component or the oxidation catalyst component, wherein the exhaust treatment fluid injection device includes a common rail that provides the exhaust treatment fluid under pressure to a plurality of injectors that dose the exhaust treatment fluid into the exhaust stream. The exhaust treatment fluid injection device also includes a return rail for returning unused exhaust treatment fluid to the fluid source. Each of the common rail and return rail can be configured to allow drainage of the exhaust treatment fluid as a freeze-protection feature.