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Urea injection systems wash cycles

  • US 9,255,512 B2
  • Filed: 08/22/2012
  • Issued: 02/09/2016
  • Est. Priority Date: 08/22/2011
  • Status: Active Grant
First Claim
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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.

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