System and apparatus for reducing reductant deposit formation in exhaust aftertreatment systems

An aftertreatment apparatus for receiving an exhaust flow, the apparatus comprising:

• at least one housing defining a decomposition chamber fluidly coupled with a substrate chamber, wherein the substrate chamber houses a catalyst and the decomposition chamber is positioned upstream of the substrate chamber, the housing including an inlet into the decomposition chamber and a reductant opening downstream of the inlet for providing a flow of reductant into the decomposition chamber;
• and
• an exhaust flow directing device positioned at least partially in the inlet, the exhaust flow directing device positioned upstream of the reductant opening,
• wherein the exhaust flow directing device is configured relative to the inlet to direct a first portion of the exhaust flow along a first flow path that extends through the exhaust flow directing device into the decomposition chamber and a second portion of the exhaust flow along a second flow path that extends around the exhaust flow directing device into the decomposition chamber, the second flow path directing the second portion of the exhaust flow towards the reductant opening, the second portion of the exhaust flow creating a shear force across the reductant opening so as to reduce formation of reductant deposits.

An aftertreatment apparatus for receiving an exhaust flow, the apparatus comprising:

• at least one housing defining a decomposition chamber fluidly coupled with a substrate chamber, wherein the substrate chamber houses a catalyst and the decomposition chamber is positioned upstream of the substrate chamber, the housing including an inlet into the decomposition chamber and a reductant opening downstream of the inlet for providing a flow of reductant into the decomposition chamber;
• and
• an exhaust flow directing device positioned at least partially in the inlet,
• wherein the exhaust flow directing device includes a frusto-conically shaped body that includes a first end and an opposite second end, the exhaust flow directing device expands in a direction of the exhaust flow and the body includes at least one slot forming a side opening of the body oriented toward the reductant opening, the slot extending from the first end to the second end, the slot oriented towards the reductant opening.

An aftertreatment apparatus for receiving an exhaust flow, the apparatus comprising:

• at least one housing defining a decomposition chamber fluidly coupled with a substrate chamber, wherein the substrate chamber houses a catalyst and the decomposition chamber is positioned upstream of the substrate chamber, the housing including an inlet into the decomposition chamber and a reductant opening downstream of the inlet for providing a flow of reductant into the decomposition chamber;
• and
• an exhaust flow directing device positioned at least partially in the inlet,
• wherein the exhaust flow directing device is configured relative to the inlet to direct a first portion of the exhaust flow along a first flow path that extends through the exhaust flow directing device into the decomposition chamber and a second portion of the exhaust flow along a second flow path that extends around the exhaust flow directing device into the decomposition chamber, the exhaust flow directing device including an inner end oriented toward the decomposition chamber and an oppositely facing outer end, and a slot that extends through a wall of the exhaust flow directing device from the inner end to the outer end, wherein the slot is oriented toward the opening for the reductant, the exhaust flow directing device further including a first wall segment and a second wall segment, wherein a first end of each of the first and second wall segments are separated by the slot and an opposite second end of the first and second wall segments are separated by a second slot.