Urea injection systems wash cycles

摘要

Urea injection system wash cycle methods and systems are disclosed. An exemplary wash cycle method includes operating a urea injection system to provide urea solution to a first inlet of a blending chamber, provide pressurized gas to a second inlet of the blending chamber, and output a combined flow of pressurized gas and urea solution from the blending chamber. A pressure of the combined flow at a location downstream from the first inlet and the second inlet is monitored. A wash cycle is performed based upon the monitored pressure wherein the flow of pressurized gas is turned off and urea solution is provided to the blending chamber. An exemplary system includes a controller configured to control a urea injection system to perform a wash cycle in accordance with the exemplary method.

主权项

1. A system for urea dosing of an exhaust aftertreatment system, the system comprising:
a blending chamber including a urea inlet, a gas inlet, and an outlet; a urea valve configured to provide urea solution to the urea inlet; a gas flow passage extending from the gas inlet; a gas valve configured to control flow of pressurized gas to the gas flow passage and the gas inlet; a pressure sensor configured to sense pressure at a location downstream from the gas inlet and the urea inlet; and a controller in operative communication with the pressure sensor, the urea valve and the gas valve; wherein the controller is configured to actuate the urea valve and the gas valve to provide a combined flow of urea solution and air at the outlet of the blending chamber, evaluate pressure information from the pressure sensor indicating pressure of the combined flow, close the gas valve based upon a comparison of the pressure information and a pressure threshold, actuate the urea valve to fill at least a portion of the blending chamber with urea solution when the pressure information is below a second threshold, the second threshold corresponding to the gas valve being completely closed, and open the gas valve to expel urea solution from the blending chamber.