Automotive exhaust aftertreatment system with multi-reductant injection and doser controls

Abstract

An automotive exhaust aftertreatment system for reducing effluents, such as nitrous oxides (NOx), in exhaust gasses passing through the system. The automotive exhaust aftertreatment system includes a doser, an active heating element, and a controller coupled to the doser and the active heating element. The doser is configured to feed a reducing agent into an exhaust stream moving through the exhaust aftertreatment system. The active heating element configured to produce heat from electrical energy and heat passageways that carry the reducing agent through the doser.

1 . (canceled) 
     
     
         2 . An exhaust aftertreatment system, the system comprising
 a doser configured to feed a reducing agent into an exhaust stream moving through the exhaust aftertreatment system so that the reducing agent reacts with exhaust gases in the exhaust stream to reduce nitrous oxides in the exhaust stream,   an active heating element configured to produce heat from electrical energy and heat passageways that carry the reducing agent through the doser, and   a controller coupled to the doser and the active heating element, the controller configured to (i) modulate a flow of the reducing agent fed by the doser into the exhaust stream based on at least one of temperature data, back pressure data, and nitrous oxide data received from sensors included in the exhaust aftertreatment system and (ii) selectively apply heat from the active heating element to manage a temperature of the reducing agent in the doser based on temperature information received from temperature sensors included in the exhaust aftertreatment system.   
     
     
         3 . The system of  claim 2 , wherein the controller is configured to selectively apply heat from the active heating element to maintain the temperature of the reducing agent within a predetermined temperature threshold when the temperature information received from the temperature sensors is outside of the predetermined temperature threshold. 
     
     
         4 . The system of  claim 3 , wherein the predetermined temperature threshold is between about 60 degrees Celsius and about 200 degrees Celsius. 
     
     
         5 . The system of  claim 2 , wherein the controller is configured to modulate the flow of the reducing agent fed by the doser into the exhaust stream based on only one of the temperature data, the back pressure data, and the nitrous oxide data received from the sensors. 
     
     
         6 . The system of  claim 2 , wherein the controller is configured to modulate the flow of the reducing agent fed by the doser into the exhaust stream based on at least two of the temperature data, the back pressure data, and the nitrous oxide data received from the sensors. 
     
     
         7 . The system of  claim 2 , further comprising another doser configured to feed the reducing agent into the exhaust stream moving through the exhaust aftertreatment system. 
     
     
         8 . The system of  claim 7 , wherein the another doser is not heated. 
     
     
         9 . The system of  claim 2 , wherein the sensors including a first pressure sensor and a second pressure sensor each located within the exhaust stream and in communication with the controller to provide measurements used in generating the back pressure data, wherein the first pressure sensor is located upstream of the doser within the exhaust stream, and the second pressure sensor is located downstream of the doser within the exhaust stream. 
     
     
         10 . The system of  claim 9 , further comprising a selective catalytic reduction unit with a catalyst mounted in the exhaust stream, wherein the second pressure sensor is located downstream of the catalyst. 
     
     
         11 . The system of  claim 2 , wherein the sensors include a first sensor and a second sensor each located within the exhaust stream and in communication with the controller to provide measurements used in generating the nitrous oxide data, the first sensor and the second sensor each configured to measure nitrous oxide levels in the exhaust stream. 
     
     
         12 . The system of  claim 11 , further comprising a selective catalytic reduction unit with a catalyst mounted in the exhaust stream, wherein the first sensor is located downstream of the catalyst and the second sensor is located upstream of the catalyst. 
     
     
         13 . A method for reducing nitrous oxide emissions, the method comprising
 feeding a flow of a reducing agent into an exhaust stream so that the reducing agent reacts with exhaust gases in the exhaust stream to reduce nitrous oxides in the exhaust stream,   modulating the flow of the reducing agent fed into the exhaust stream based on at least one of temperature data, back pressure data, and nitrous oxide data, and   selectively applying heat to the reducing agent to manage a temperature of the reducing agent based on temperature information.   
     
     
         14 . The method of  claim 13 , wherein selectively applying heat step includes maintain the temperature of the reducing agent within a predetermined temperature threshold. 
     
     
         15 . The method of  claim 14 , wherein the predetermined temperature threshold is between about 60 degrees Celsius and about 200 degrees Celsius. 
     
     
         16 . The method of  claim 13 , further comprising modulating the flow of the reducing agent fed into the exhaust stream based on only one of the temperature data, the back pressure data, and the nitrous oxide data received from sensors. 
     
     
         17 . The system of  claim 12 , further comprising modulating the flow of the reducing agent fed into the exhaust stream based on at least two of the temperature data, the back pressure data, and the nitrous oxide data received from sensors.