Reductant supply system

Abstract

A reductant supply system for an engine aftertreatment device is provided. The reductant supply system includes a tank configured to store a reductant. The reductant supply system includes a filter configured to receive the reductant from the tank. The filter defines a filtered volume therein. The reductant supply system includes a suction conduit in fluid communication with the filtered volume. The reductant supply system also includes a pump in fluid communication with the suction conduit. The pump is configured to pressurize the reductant. The reductant supply system further includes a return conduit configured to recirculate at least a part of the reductant pressurized by the pump to the filtered volume.

What is claimed is: 
     
         1 . A reductant supply system for an engine aftertreatment device, the reductant supply system comprising:
 a tank configured to store a reductant;   a filter configured to receive the reductant from the tank, wherein the filter defines a filtered volume therein;   a suction conduit in fluid communication with the filtered volume;   a pump in fluid communication with the suction conduit, wherein the pump is configured to pressurize the reductant; and   a return conduit configured to recirculate at least a part of the reductant pressurized by the pump to the filtered volume.   
     
     
         2 . The reductant supply system of  claim 1 , wherein the filter is disposed within the tank. 
     
     
         3 . The reductant supply system of  claim 1 , wherein the filter is at least one of a sock filter and a pickup filter. 
     
     
         4 . The reductant supply system of  claim 1 , wherein the return conduit comprises an air vent. 
     
     
         5 . The reductant supply system of  claim 1 , wherein the return conduit is in fluid communication with the suction conduit within the filter. 
     
     
         6 . The reductant supply system of  claim 1 , wherein the suction conduit comprises:
 a partition configured to at least partly divide the suction conduit into a first portion and a second portion within the filtered volume,   wherein the first portion is in fluid communication with the pump;   wherein the second portion is in fluid communication with the return conduit; and   wherein the second portion is in fluid communication with the first portion within the filtered volume.   
     
     
         7 . The reductant supply system of  claim 1  further comprises a throttling device provided in the return conduit. 
     
     
         8 . The reductant supply system of  claim 7  further comprises a check valve provided in the return conduit between the throttling device and the tank. 
     
     
         9 . The reductant supply system of  claim 1  further comprises an outlet conduit configured to receive the reductant pressurized by the pump, wherein the return conduit is in fluid communication with the outlet conduit. 
     
     
         10 . The reductant supply system of  claim 1  further comprises a main filter configured to filter the reductant pressurized by the pump. 
     
     
         11 . A method of supplying a reductant to an engine aftertreatment device, the method comprising:
 filtering the reductant by a filter, wherein the filter defines a filtered volume therein;   supplying the reductant from the filtered volume to a pump via a suction conduit;   pressurizing the reductant by the pump; and   recirculating at least a part of the reductant pressurized by the pump to the filtered volume via a return conduit.   
     
     
         12 . The method of  claim 11  further comprises throttling the reductant recirculated to the filtered volume. 
     
     
         13 . The method of  claim 11  further regulating the reductant recirculated to the filtered volume by a check valve provided in the return conduit. 
     
     
         14 . The method of  claim 11  further comprises fluidly communicating the suction conduit and the return conduit within the filter. 
     
     
         15 . The method of  claim 11  further comprises:
 determining a requirement of the reductant by the engine aftertreatment device; 
 supplying a portion of the reductant pressurized by the pump to the engine aftertreatment device based on the determined requirement; and 
 recirculating rest of the reductant pressurized by the pump to the filtered volume. 
 
     
     
         16 . A machine comprising:
 an engine configured to generate an exhaust gas;   an engine aftertreatment device configured to treat the exhaust gas, the engine aftertreatment device comprising a Selective Catalytic Reduction (SCR) module; and   a reductant supply system comprising:
 a tank configured to store a reductant; 
 a filter configured to receive the reductant from the tank, wherein the filter defines a filtered volume therein; 
 a suction conduit in fluid communication with the filtered volume; 
 a pump in fluid communication with the suction conduit, wherein the pump is configured to pressurize the reductant; 
 an outlet conduit configured to receive the reductant pressurized by the pump; 
 a main filter provided in the outlet conduit, wherein the main filter is configured to filter the reductant pressurized by the pump; 
 an injector configured to receive a portion of the reductant filtered by the main filter via the outlet conduit, wherein the injector is configured to dispense the reductant into the exhaust gas upstream of the Selective Catalytic Reduction (SCR) module of the engine aftertreatment device; and 
 a return conduit in fluid communication with the outlet conduit downstream of the main filter, wherein the return conduit is configured to recirculate rest of the reductant filtered by the main filter to the filtered volume. 
   
     
     
         17 . The machine of  claim 16 , wherein the filter is one of a sock filter and a pickup filter. 
     
     
         18 . The machine of  claim 16 , wherein the return conduit is in fluid communication with the suction conduit within the filter. 
     
     
         19 . The machine of  claim 16 , wherein the suction conduit comprises:
 a partition configured to at least partly divide the suction conduit into a first portion and a second portion within the filtered volume;   wherein the first portion is in fluid communication with the pump;   wherein the second portion is in fluid communication with the return conduit; and   wherein the second portion is in fluid communication with the first portion within the filtered volume.   
     
     
         20 . The machine of  claim 16  further comprises a throttling device provided in the return conduit.