Device for introducing a fluid into a gas stream

Abstract

The present invention relates to a device for introducing a fluid into a gas stream, in particular a reduction agent into an exhaust gas stream of an internal combustion engine. The device has a mixing chamber and a metering device by means of which the fluid can be introduced, via a metering tip, into an injection space defined by a protective sleeve, which injection space is arranged inside the chamber and is fluidically connected to the latter. The protective sleeve has an intermediate chamber which extends in the circumferential direction of the protective sleeve and is bounded radially internally by an inner wall and radially externally by an outer wall, wherein the intermediate chamber is fluidically connected to the injection space via a gap, in particular an annular gap, formed by and at the inner wall. The intermediate chamber is also fluidically connected to the mixing chamber via at least one opening in the outer wall.

1 - 35 . (canceled) 
     
     
         36 . An apparatus for introducing a fluid into a gas flow, the apparatus having a mixing chamber and having a metering apparatus through which the fluid can be introduced by means of a metering tip into an injection space, the injection space being defined by a protective sleeve in a radial direction, the injection space being arranged in the interior of the mixing chamber, and the injection space being in fluid communication with the mixing chamber, wherein the protective sleeve has an intermediate chamber that extends in the peripheral direction of the protective sleeve, the intermediate chamber being bounded at the radially inner side by an inner wall and at the radially outer side by an outer wall, with the intermediate chamber being in fluid communication with the injection space via one of a gap formed by the inner wall and a gap configured at the inner wall and the intermediate chamber being in fluid communication with the mixing chamber via at least one opening in the outer wall. 
     
     
         37 . The apparatus in accordance with  claim 36 ,
 wherein the gap at least partly or completely surrounds the metering tip in the peripheral direction.   
     
     
         38 . The apparatus in accordance with  claim 36 ,
 wherein the gap is arranged such that at least some of the gas flow flowing therethrough flushes behind the metering tip.   
     
     
         39 . The apparatus in accordance with  claim 36 ,
 wherein at least one guide element is arranged in the gap and a swirl component can be imparted through said gap onto at least some of the gas flow flowing therethrough.   
     
     
         40 . The apparatus in accordance with  claim 36 ,
 wherein a part of a wall of the mixing chamber at least sectionally bounds the intermediate chamber.   
     
     
         41 . The apparatus in accordance with  claim 36 ,
 wherein an end of the intermediate chamber facing the metering tip is at least sectionally bounded by a base section of the protective sleeve.   
     
     
         42 . The apparatus in accordance with  claim 41 ,
 wherein the base section is arranged spaced apart from a wall of the mixing chamber.   
     
     
         43 . The apparatus in accordance with  claim 36 ,
 wherein the gap is bounded by an end section of the inner wall facing the metering tip, by a part of a wall of the mixing chamber sectionally bounding the intermediate chamber and/or by the base section.   
     
     
         44 . The apparatus in accordance with  claim 36 ,
 wherein the inner wall is provided at its end facing the metering tip with a collar that projects into the intermediate chamber.   
     
     
         45 . The apparatus in accordance with  claim 36 ,
 wherein the at least one opening in the outer wall is a bore, an elongate hole and/or a slit.   
     
     
         46 . The apparatus in accordance with  claim 36 ,
 wherein the inner wall has a funnel-like or conical section that opens in a direction away from the metering tip.   
     
     
         47 . The apparatus in accordance with  claim 36 ,
 wherein the inner wall is formed without interruption.   
     
     
         48 . The apparatus in accordance with  claim 36 ,
 wherein the outer wall has a funnel-like or conical section that opens in a direction facing the metering tip.   
     
     
         49 . The apparatus in accordance with  claim 36 ,
 wherein the protective sleeve is formed in one piece.   
     
     
         50 . The apparatus in accordance with  claim 36 ,
 wherein the outer wall and the inner wall of the protective sleeve are separate elements that are connected to one another.   
     
     
         51 . The apparatus in accordance with  claim 36 ,
 wherein the protective sleeve is substantially rotationally symmetrical.   
     
     
         52 . The apparatus in accordance with  claim 36 ,
 wherein the mixing chamber has at least one inlet opening that is arranged and configured such that the protective sleeve is flowed on by at least some of the gas flow flowing into the mixing chamber.   
     
     
         53 . The apparatus in accordance with  claim 52 ,
 wherein a respective at least one opening in the outer wall is associated with each inlet opening.   
     
     
         54 . The apparatus in accordance with  claim 36 ,
 wherein a gas conductance element that guides at least some of the gas flow toward the protective sleeve is arranged in the mixing chamber.   
     
     
         55 . The apparatus in accordance with  claim 54 ,
 wherein the gas conductance element is connected to the protective sleeve and projects into the gas flow flowing onto the protective sleeve.   
     
     
         56 . The apparatus in accordance with  claim 55 ,
 wherein the gas conductance element is associated with at least one opening to guide a portion of the gas flow into the opening.   
     
     
         57 . The apparatus in accordance with  claim 54 ,
 wherein the gas conductance element has a section that is configured in U shape or has the form of a complete U.   
     
     
         58 . The apparatus in accordance with  claim 54 ,
 wherein the gas conductance element is at least partly formed by a section of the outer wall of the protective sleeve.   
     
     
         59 . The apparatus in accordance with  claim 54 ,
 wherein the gas conductance element projects into an inlet opening of the mixing chamber or therethrough.   
     
     
         60 . The apparatus in accordance with  claim 36 ,
 wherein the mixing chamber has a bypass flow path through which at least some of the gas flow flows into or through the mixing chamber without flowing onto the protective sleeve or without flowing through the protective sleeve.   
     
     
         61 . The apparatus in accordance with  claim 60 ,
 wherein the bypass flow path is at least sectionally defined by a wall of the mixing chamber and by an end of the protective sleeve remote from the metering tip.   
     
     
         62 . The apparatus in accordance with  claim 36 ,
 wherein the wall of the mixing chamber has an inwardly directed bead that is arranged approximately at the level of the protective sleeve in the axial direction of the mixing chamber.   
     
     
         63 . The apparatus in accordance with  claim 36 ,
 wherein a gas conductance pipe whose outer periphery is arranged spaced apart from the wall of the mixing chamber is arranged in the mixing chamber.   
     
     
         64 . The apparatus in accordance with  claim 63 ,
 wherein at least one flow conductance element is arranged between the outer periphery of the gas conductance pipe and the wall of the mixer chamber.   
     
     
         65 . The apparatus in accordance with  claim 63 ,
 wherein at least one flow conductance element is provided that is arranged in the gas conductance pipe or that at least sectionally projects into the gas conductance pipe.   
     
     
         66 . The apparatus in accordance with  claim 65 ,
 wherein the flow conductance element is arranged between the protective sleeve and the gas conductance pipe.   
     
     
         67 . The apparatus in accordance with  claim 63 ,
 wherein the protective sleeve projects at least sectionally into the gas conductance pipe in the axial direction.   
     
     
         68 . The apparatus in accordance with  claim 63 ,
 wherein the gas conductance pipe has a section that flares in the flow direction of the gas flow.   
     
     
         69 . The apparatus in accordance with  claim 63 ,
 wherein the gas conductance pipe has a funnel-like inlet region and/or a constriction with a reduced cross-section and/or a curved section.   
     
     
         70 . The apparatus in accordance with  claim 63 ,
 wherein the gas conductance pipe is arranged coaxially to the mixing chamber and/or to the protective sleeve.