Mixing cavity assembly

Abstract

A mixing chamber assembly adapted for an engine aftertreatment system includes a first sub-compartment, a second sub-compartment, a mounting hole for installing a urea injector for spraying urea droplets into the first sub-compartment, and a middle sub-compartment connecting the first sub-compartment and the second sub-compartment. A mixer is positioned in the middle sub-compartment and includes a plurality of first blades inclined to the second sub-compartment. The first blades are divided into two groups of different inclined directions in order to achieve a double-swirl mixing effect. A plurality of second blades are inclined in the same direction and positioned upstream the first blades. As a result, flow distance within limited space can be increased to assure sufficient mixing of the urea droplets and the exhaust gas. The urea droplets are sufficiently heated to improve urea evaporation rate, improve uniformity of ammonia molecule and reduce the risk of urea deposits.

What is claimed is: 
     
         1 . A mixing chamber assembly adapted for an engine aftertreatment system, the mixing chamber assembly comprising:
 a compartment and a mounting hole for mounting a urea injector, the compartment being partitioned to a first sub-compartment, a second sub-compartment and a middle sub-compartment connected between the first sub-compartment and the second sub-compartment, the first sub-compartment being positioned upstream the second sub-compartment and adapted to receive urea droplets from the urea injector; and   a mixer positioned in the middle sub-compartment, the mixer comprising a plurality of first blades arranged in a first row and inclined to the second sub-compartment, a plurality of second blades arranged in a second row and inclined to the first sub-compartment, the second blades being inclined to a same direction, the second blades being positioned upstream the first blades, the first blades being divided into a first group and a second group, the first blades of the first group and the first blades of the second group being in a V-shaped position relationship in order to form a double-swirl mixing effect in the second sub-compartment.   
     
     
         2 . The mixing chamber assembly as claimed in  claim 1 , wherein the first blades face at least partly in opposite directions. 
     
     
         3 . The mixing chamber assembly as claimed in  claim 1 , wherein the first blades of the first group and the first blades of the second group are of an angle being smaller than 90°. 
     
     
         4 . A mixing chamber assembly adapted for an engine aftertreatment system, the mixing chamber assembly comprising:
 a compartment and a mounting hole for mounting a urea injector, the compartment being partitioned to a first sub-compartment, a second sub-compartment and a middle sub-compartment connected between the first sub-compartment and the second sub-compartment, the first sub-compartment being positioned upstream the second sub-compartment and adapted to receive urea droplets from the urea injector; and   a mixer positioned in the middle sub-compartment, the mixer comprising a plurality of first blades arranged in a first row and inclined to a main flow direction of exhaust gas (MF) through the second sub-compartment, and a plurality of second blades arranged in a second row and inclined to the first sub-compartment, the second blades being inclined to a same direction, the second blades being positioned upstream the first blades, the first blades being divided into a first group and a second group, the first blades of the first group and the first blades of the second group being in a V-shaped position relationship in order to form a double-swirl mixing effect in the second sub-compartment.   
     
     
         5 . The mixing chamber assembly as claimed in  claim 4 , wherein the first blades face at least partly in opposite directions. 
     
     
         6 . The mixing chamber assembly as claimed in  claim 5 , wherein along the main flow direction (MF), configurations of the first blades are straight, or curved, or bended, or a combination thereof. 
     
     
         7 . The mixing chamber assembly as claimed in  claim 6 , wherein the first blades comprise holes, or perforations, or flaps, or a combination thereof. 
     
     
         8 . The mixing chamber assembly as claimed in  claim 6 , wherein a cross section of each first blade along a width direction thereof is straight, or curved, or bended, or a combination thereof. 
     
     
         9 . The mixing chamber assembly as claimed in  claim 4 , further comprising a body portion and a cover for mating with the body portion, the body portion comprising a side plate and a side wall extending from the side plate, the cover being fixed to the side wall, the first sub-compartment, the second sub-compartment and the middle sub-compartment being formed by the body portion and the cover. 
     
     
         10 . The mixing chamber assembly as claimed in  claim 9 , wherein the cover defines a first opening in communication with the first sub-compartment and a second opening in communication with the second sub-compartment, the mounting hole being positioned at the side wall. 
     
     
         11 . The mixing chamber assembly as claimed in  claim 4 , wherein the first blades of the first group and the first blades of the second group are of an angle being smaller than 90°. 
     
     
         12 . The mixing chamber assembly as claimed in  claim 10 , wherein the side wall comprises a first side wall which at least partly defines the first sub-compartment, a second side wall which at least partly defines the second sub-compartment and a third side wall which at least partly defines the middle sub-compartment, wherein
 the first side wall comprises a first left side wall and a first right side wall, the second side wall comprises a second left side wall and a second right side wall, the third side wall comprises a third left side wall and a third right side wall, and wherein   the second blades are inclined to the first right side wall or both to the first left side wall and to the first right side wall.   
     
     
         13 . The mixing chamber assembly as claimed in  claim 12 , wherein the first blades of the first group are inclined to the main flow direction (MF), the first blades of the second group are inclined to the main flow direction (MF) and inner sides of the second left side wall and the second right side wall are curved. 
     
     
         14 . The mixing chamber assembly as claimed in  claim 12 , wherein the first sub-compartment is offset from the second sub-compartment, the mixing chamber assembly comprising an inclined portion between the first sub-compartment and the second sub-compartment along a thickness direction (A-A) thereof in order to form a contracted space. 
     
     
         15 . The mixing chamber assembly as claimed in  claim 13 , wherein the second blades are straight and slightly inclined to the cover in order to be uncompletely perpendicular to the side plate, the first blades of the second group are straight and slightly inclined to the cover in order to be uncompletely perpendicular to the side plate as well. 
     
     
         16 . The mixing chamber assembly as claimed in  claim 4 , wherein the first blades and the second blades are separated from each other along the main flow direction (MF) and form an empty there between, the mixer comprising a bracket for fixing the first blades and the second blades, the bracket comprising a plurality of inclined slots to receive the first blades and the second blades. 
     
     
         17 . The mixing chamber assembly as claimed in  claim 4 , wherein configurations of the first blades are straight, or curved, or bended, or a combination thereof. 
     
     
         18 . The mixing chamber assembly as claimed in  claim 17 , wherein the first blades comprise holes, or perforations, or flaps, or a combination thereof. 
     
     
         19 . The mixing chamber assembly as claimed in  claim 17 , wherein a cross section of each first blade along a width direction thereof is straight, or curved, or bended, or a combination thereof. 
     
     
         20 . The mixing chamber assembly of  claim 4 , wherein the second blades are arranged to be impacted by the urea droplets sprayed into the first sub-compartment.