Aftertreatment system having multiple dosing circuits

Abstract

An aftertreatment system is disclosed for use with a combustion engine. The aftertreatment system may have at least one exhaust passage, and a plurality of dosing circuits configured to inject reductant into the at least one exhaust passage. The aftertreatment system may also have a controller in communication with each of the plurality of dosing circuits. The controller may be configured to determine a failure of a first of the plurality of dosing circuits, and to selectively adjust operation of a second of the plurality of dosing circuits based on the failure.

What is claimed is: 
     
         1 . An aftertreatment system, comprising:
 at least one exhaust passage;   a plurality of dosing circuits configured to inject reductant into the at least one exhaust passage; and   a controller in communication with each of the plurality of dosing circuits, the controller being configured to:
 determine a failure of a first of the plurality of dosing circuits; and 
 selectively adjust operation of a second of the plurality of dosing circuits based on the failure. 
   
     
     
         2 . The aftertreatment system of  claim 1 , wherein:
 the at least one exhaust passage includes a first passage and a second passage in parallel with the first passage;   the first of the plurality of dosing circuits is associated with the first passage; and   the second of the plurality of dosing circuits is associated with the second passage.   
     
     
         3 . The aftertreatment system of  claim 1 , wherein:
 the at least one exhaust passage includes a single passage; and   the first of the plurality of dosing circuits is disposed in series with the second of the plurality of dosing circuits.   
     
     
         4 . The aftertreatment system of  claim 1 , wherein the controller is configured to increase dosing of the second of the plurality of dosing circuits based on the failure to maintain an overall consistent discharge of exhaust emissions. 
     
     
         5 . The aftertreatment system of  claim 4 , wherein the controller is further configured to shut down the first of the plurality of dosing circuits based on the failure. 
     
     
         6 . The aftertreatment system of  claim 1 , wherein the failure includes one of a failure of a supply of reductant, a failure of a pump, or a failure of an injector. 
     
     
         7 . The aftertreatment system of  claim 1 , wherein the failure includes a reduction in conversion efficiency of the first of the plurality of dosing circuits. 
     
     
         8 . The aftertreatment system of  claim 1 , wherein the controller is further configured to:
 determine a demand for dosing from each of the plurality of dosing circuits that is below a threshold amount; and   selectively inhibit operation of the first of the plurality of dosing circuits to cause an amount of reductant injected by the second of the plurality of dosing circuits to increase above the threshold amount.   
     
     
         9 . The aftertreatment system of  claim 1 , further including at least one sensor configured to detect a performance parameter of the plurality of dosing circuits, wherein the controller is configured to determine the failure based on signals from the at least one sensor. 
     
     
         10 . The aftertreatment system of  claim 9 , wherein the at least one sensor is an exhaust constituent sensor. 
     
     
         11 . The aftertreatment system of  claim 9 , wherein the at least one sensor is slip Sensor. 
     
     
         12 . The aftertreatment system of  claim 9 , wherein the at least one sensor is a reductant supply sensor. 
     
     
         13 . A method of dosing reductant, comprising:
 dosing reductant into an exhaust flow using a plurality of dosing circuits;   determining a failure of a first of the plurality of dosing circuits; and   selectively adjusting operation of a second of the plurality of dosing circuits based on the failure.   
     
     
         14 . The method of  claim 13 , wherein:
 dosing reductant into an exhaust flow includes dosing reductant into parallel legs of the exhaust flow;   the first of the plurality of dosing circuits is associated with a first of the parallel legs; and   the second of the plurality of dosing circuits is associated with a second of the parallel Legs.   
     
     
         15 . The method of  claim 13 , wherein dosing reductant into an exhaust flow includes dosing reductant into of the exhaust flow at multiple locations in series with each other. 
     
     
         16 . The method of  claim 13 , wherein selectively adjusting operation of the second of the plurality of dosing circuits includes selectively increasing dosing of the second of the plurality of dosing circuits based on the failure to maintain an overall consistent discharge of exhaust emissions. 
     
     
         17 . The method of  claim 16 , further including selectively shutting down the first of the plurality of dosing circuits based on the failure. 
     
     
         18 . The method of  claim 16 , wherein determining the failure includes determining the failure of one of a supply or reductant, a pump, or an injector. 
     
     
         19 . The method of  claim 18 , further including:
 determining a demand for dosing from each of the plurality of dosing circuits that is below a threshold amount; and   selectively inhibiting operation of the first of the plurality of dosing circuits so as to cause an amount of reductant injected by the second of the plurality of dosing circuits to increase above the threshold amount.   
     
     
         20 . An engine, comprising:
 an engine block at least partially defining a plurality of combustion chambers;   an exhaust manifold extending from the plurality of combustion chambers;   a turbocharger connected to the exhaust manifold;   a first branch passage connected to an outlet of the turbocharger;   a second branch passage connected to the outlet of the turbocharger in parallel with the first branch passage;   at least a first dosing circuit associated with the first branch passage;   at least a second dosing circuit associated with the second branch passage;   at least one sensor configured to generate a signal indicative of a performance parameter of the at least a first and at least a second dosing circuits; and   a controller in communication with the at least one sensor and each of the at least a first and at least a second dosing circuits, the controller being configured to:
 make a determination of one of a failure of the at least a first dosing circuit and occurrence of a low-dosing event based on the signal; 
 selectively inhibit operation of the at least a first dosing circuit based on the determination; and 
 selectively increase dosing of the at least a second dosing circuit based on the determination so as to maintain an overall consistent discharge of exhaust emissions from both of the first and second branch passages.