After treatment system for a vehicle
An after treatment system (ATS) for a vehicle includes, fluidly connected in series, an inlet, a urea mixer and an outlet. The inlet is fluidly connected to an output of an engine of the vehicle and the outlet is fluidly connected to an outlet tube of the vehicle. The urea mixer is provided with a dosing module, an inner element and an outer element. The inner element is configured such that a first flow of exhaust gas flow flowing from the inlet into the urea mixer flows into an first volume defined by the inner element. The outer element is configured such that a second flow flows in a volume defined between inner element and outer element, wherein the first and second flows rejoin together in a mixing chamber fluidly connected to the volume and to the first volume downstream with respect inner and outer elements.
1. An after treatment system for a vehicle comprises:
an inlet fluidly connected to an output of an engine of the vehicle;
an urea mixer comprising:
a dosing module;
an inner element that defines a first volume, the inner element comprising a heat exchanger connected to a lateral surface of the inner element and extending into the first volume, wherein the inner element is configured such that a first flow of exhaust gas flow flowing from the inlet into the urea mixer flows into the first volume; and
an outer element, wherein a second volume is defined between the inner element and outer element, and wherein the outer element is configured such that a second flow of the exhaust gas flows in the second volume,
wherein the first and second flows rejoin together in a mixing chamber fluidly connected to the second volume and to the first volume downstream with respect the inner and outer elements,
wherein the heat exchanger comprises at least one fin extending in the second volume from the lateral surface of the inner element, the heat exchanger being configured to draw heat energy from the second flow flowing in the second volume to the first volume; and
an outlet fluidly connectable to an outlet tube of the vehicle,
wherein the inlet, urea mixer, and outlet are fluidly connected in series.
2. The after treatment system according to claim 1 , wherein the first flow comprises between 35% and 45% of a total exhaust flow coming from the inlet into the urea mixer.
3. The after treatment system according to claim 1 , wherein the at least one fin defines at least one channel, or chamber, in which the second flow is forced to flow.
4. The after treatment system according to claim 1 , wherein the at least one fin is configured to impart a swirl to the second flow before its emission in the mixing chamber.
5. The after treatment system according to claim 1 , further comprising a Diesel Oxidation Catalysts (DOC), wherein the inner element comprises at least one opening fluidly connected to the DOC and the first volume.
6. The after treatment system according to claim 5 , wherein at least one edge of the at least one opening is provided with a protrusion configured to generate a swirl to the first flow flowing from DOC to first volume through the at least one opening.
7. The after treatment system according to claim 1 , wherein the outer element comprises a terminal plate carried downstream with respect to the dosing module and configured to deviate flow radially out with respect to first volume.
8. The after treatment system according to claim 7 , wherein the terminal plate has a convex surface.
9. The after treatment system according to claim 7 , wherein the terminal plate comprises a protuberance extending into the first volume.
10. The after treatment system according to claim 1 , wherein the outer element comprises, downstream with respect to the dosing module, at least one opening, the at least one opening being in fluidic communication with the mixing chamber, the first volume and the second volume, so as to allow the passage of the first flow and the second flow into the mixing chamber.
11. The after treatment system according to claim 10 , wherein the at least one opening comprises at least one edge and a baffle on the at least one edge configured to deviate flow coming out from the at least one opening.
12. The after treatment system according to claim 1 , wherein the outer element is cylindrical and it is placed coaxially around the inner element so as a terminal portion of the inner element is not radially interposed with respect the outer element and a terminal portion of the outer element is not radially interposed with respect the inner element.
13. The after treatment system according to claim 1 , wherein the dosing module is perpendicular with respect to the flow flowing into the mixer from the inlet.