System for injecting reactants in an exhaust line

Abstract

A system to be fitted on an automotive vehicle for injecting reactants in an exhaust line of an engine of the vehicle includes a source of a liquid precursor of ammonia, a source of gaseous ammonia, an injection assembly designed to be fitted on the exhaust line and to inject liquid precursor and/or gaseous ammonia inside the exhaust line, the injection assembly including a single injector body to be fitted on the exhaust line, the injector body having a first inlet for the liquid precursor, a second inlet for the gaseous ammonia, and at least one outlet for injection inside the exhaust line.

1 . A system to be fitted on an automotive vehicle for injecting reactant(s) in an exhaust line of an engine of the vehicle, wherein the system comprises:
 a source of a liquid precursor of ammonia; a source of gaseous ammonia;   an injection assembly designed to be fitted on the exhaust line and to inject liquid precursor and/or gaseous ammonia inside the exhaust line, the injection assembly comprising a single injector body to be fitted on the exhaust line, the injector body having a first inlet for the liquid precursor, a second inlet for the gaseous ammonia, and at least one outlet for injection inside the exhaust line.   
     
     
         2 . The system according to  claim 1 , wherein the injector body comprises one or several common outlets for the liquid precursor and the gaseous ammonia, the flow path of the liquid precursor and the flow path of the gaseous ammonia inside the injector body having at least a common downstream portion. 
     
     
         3 . The system according to  claim 1 , wherein the first and second inlets ( 21 ,  22 ) are separate and in that the injector body comprises at least one first outlet for the liquid precursor and at least one second outlet for the gaseous ammonia, the first outlet(s) being separate from the second outlet(s), the flow path of the liquid precursor and the flow path of the gaseous ammonia inside the injector body being separate. 
     
     
         4 . The system according to  claim 1 , wherein it further comprises a flow control system for controlling the flow of liquid precursor and/or gaseous ammonia to be injected by the injection assembly. 
     
     
         5 . The system according to  claim 4 , wherein the flow control system ( 11 ) comprises at least one dosing device for dosing the liquid precursor and/or the gaseous ammonia to be injected inside the exhaust line. 
     
     
         6 . The system according to  claim 5 , wherein one dosing device is housed inside the injector body. 
     
     
         7 . The system according to  claim 5 , wherein one dosing device is located outside and upstream from the injector body. 
     
     
         8 . The system according to  claim 5 , wherein the flow control system comprises one first dosing device ( 24   a ) arranged on the liquid circuit extending from the source of the liquid precursor of ammonia to the injector body. 
     
     
         9 . The system according to  claim 5 , wherein the flow control system comprises one second dosing device arranged on the gas circuit extending from the source of gaseous ammonia to the injector body. 
     
     
         10 . The system according to  claim 8 , wherein the flow control system comprises one second dosing device arranged on the gas circuit extending from the source of gaseous ammonia to the injector body, and the first and second dosing devices are separate. 
     
     
         11 . The system according to  claim 8 , wherein the flow control system comprises one second dosing device arranged on the gas circuit extending from the source of gaseous ammonia to the injector body the first and second dosing devices are one and the same device and are arranged in a common portion of the liquid circuit and the gas circuit. 
     
     
         12 . The system according to  claim 5 , wherein the dosing device comprises a controlled valve capable of allowing all or part of the liquid precursor flow and/or all or part of the gaseous ammonia flow towards the injector body outlet(s), or of blocking the flow(s). 
     
     
         13 . The system according to  claim 5 , wherein the flow control system comprises a control unit for controlling the dosing device(s) according to at least one operational parameter. 
     
     
         14 . The system according to  claim 1 , wherein it further comprises an air line for carrying air towards an inlet of the injector body in order to assist the injection of the liquid precursor. 
     
     
         15 . The system according to  claim 13 , wherein the air line is fluidically connected to a gas circuit ( 16 ), which extends from the source of gaseous ammonia to the injector body. 
     
     
         16 . The system according to  claim 1 , wherein the injection assembly is designed to be fitted on the exhaust line so as to be capable of injecting liquid precursor and/or gaseous ammonia inside the exhaust line upstream from a selective catalytic reduction device, the system therefore allowing treating nitrogen oxides contained in exhaust gases flowing in the exhaust line. 
     
     
         17 . The system according to  claim 16 , wherein the source of gaseous ammonia comprises a unit including a container containing a material which, depending on the operating conditions, is capable of retaining gaseous ammonia in order to store it, and of releasing retained gaseous ammonia. 
     
     
         18 . The system according to  claim 17 , wherein the material contained in the unit is capable of retaining gaseous ammonia by absorption and/or adsorption and/or formation of chemical complexes. 
     
     
         19 . The system according to  claim 17 , wherein the material contained in the unit is capable of releasing retained gaseous ammonia above a threshold temperature, and in that the unit further comprises a heater capable of heating the material above the threshold temperature. 
     
     
         20 . The system according to  claim 1 , wherein the liquid precursor of ammonia comprises an aqueous solution of urea. 
     
     
         21 . The system according to  claim 1 , wherein it comprises a tank ( 12 ) for storing the liquid precursor and a container for storing gaseous ammonia, the tank ( 12 ) and the container being juxtaposed in a same supply unit ( 38 ). 
     
     
         22 . The system according to  claim 4 , wherein the flow control system is fully housed in a control box ( 39 ). 
     
     
         23 . An automotive vehicle equipped with a system according to  claim 1 .