Device To Convey A Checmical Reactant Into The Exhaust Gas Stream Of A Combustion Engine

A device for supplying a chemical reactant into an exhaust system of an internal combustion engine, comprising:

• a mixer housing with an inlet opening through which an exhaust gas flow enters into the mixer housing,
• a metering pipe with a first end and a second end, towards which the exhaust gas flow flowing into the mixer housing flows in a transverse direction, wherein a longitudinal extension of the metering pipe extends between the first end and the second end,
• a metering unit which is arranged at the first end of the metering pipe and connectable to a reactant supply for discharging reactant into the metering pipe, and
• means for generating a swirl flow of the exhaust gas flow, wherein said means are designed to generate the swirl flow within the metering pipe, wherein the metering pipe has at least one in-flow opening extending over at least one section of a length of the metering pipe located within the mixer housing, with at least one shovel-shaped hood arranged on the metering pipe directing the exhaust gas flow eccentrically into a respective in-flow opening, wherein the hood encloses the in-flow opening at the side and back thereof and at least mostly covers the in-flow opening in the radial direction of the metering pipe, and wherein a gap remains between the hood and an inner casing surface of the mixer housing,
• wherein the metering pipe engages through the mixer housing, and the at least one in-flow opening of the metering pipe extends over a casing surface segment of no less than 45° in the circumferential direction, and in an angular configuration has a trapezoidal outline geometry, wherein the shorter side of the trapezoidal outline geometry is, in relation to the inflow direction of the exhaust gas, a rear edge of the in-flow opening following the longitudinal extension, wherein the metering unit injects the reactant under pressure into the metering pipe, and a spray cone of the reactant being injected into the metering pipe, in the longitudinal extension of the metering pipe in the direction of the second end of the metering pipe, only emerges behind the at least one in-flow opening onto an inner wall section of the metering pipe, and the exhaust gas flowing into the device flows on the outside of this inner wall section of the metering pipe.