System for adding and processing reducing agent in a motor vehicle

Patent metadata

Field	Value
Publication number	US-9341100-B2
Application number	US-201314404106-A
Country	US
Kind code	B2
Filing date	May 8, 2013
Priority date	Jun 1, 2012
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

A system for adding and processing reducing agent includes an injector connected to a reducing agent metering unit and which can spray a jet of reducing agent into the exhaust gas. A mixing pipe is disposed in an exhaust pipe of the internal combustion engine and a funnel element is disposed on or in the mixing pipe in the region of the first mixing pipe end. The mixing pipe and the funnel element are formed as hollow bodies having perforated outer surfaces, the perforation of the mixing pipe has a larger surface area than the perforation of the funnel element. The funnel element has a passage opening on the end of the funnel element assigned to the first mixing pipe end, and the reducing agent metering unit is disposed such that the injector sprays the jet of reducing agent through the passage opening into the interior of the funnel element.

First claim

The invention claimed is:

1. A reducing agent addition and preparation system of a motor vehicle, configured to add a liquid reducing agent to exhaust gas emitted by an internal combustion engine of the motor vehicle and to prepare the added reducing agent in the exhaust gas, the system comprising:
a reducing agent metering unit;
an injector connected to the reducing agent metering unit and configured to spray a reducing agent spray jet into the exhaust gas;
a mixing tube situated in an exhaust tract of the internal combustion engine and having a first and a second axial mixing tube end; and
a funnel element situated on or in the mixing tube in a region of the first mixing tube end, wherein the funnel element widens conically at a predetermined widening angle in a direction from the first mixing tube end toward the second mixing tube end,
wherein the mixing tube and the funnel element are hollow bodies having a respective perforated lateral surface, and a perforation of the mixing tube has an at least predominantly larger surface area than a perforation of the funnel element,
wherein the funnel element has a passage opening on an end of the funnel element situated on or in the first mixing tube end, and
wherein the reducing agent metering unit is situated in such a way that the injector sprays the reducing agent spray jet through the funnel element passage opening into an interior of the funnel element.

2. The reducing agent addition and preparation system of claim 1 , wherein rotational axes of the mixing tube and the funnel element at least approximately coincide, and the funnel element passage opening is situated at least approximately centrally with respect to the rotational axis.

3. The reducing agent addition and preparation system of claim 1 , wherein an end of the injector has an injector tip, wherein the injector tip and the funnel element passage opening each have an at least approximately circular perimeter, and the end of the injector has an outlet opening for the reducing agent situated at least approximately centrally at the injector tip, and the outlet opening and center point of the of the passage opening are situated at least approximately on a rotational axis of the funnel element.

4. The reducing agent addition and preparation system of claim 3 , wherein the injector tip is situated opposite from the funnel element at a small distance from the passage opening in such a way that the injector tip and a lateral surface region of the funnel element surrounding the passage opening form an annular gap through which exhaust gas flows into the interior of the funnel element.

5. The reducing agent addition and preparation system of claim 4 , wherein the annular gap is dimensioned in such a way that exhaust gas flowing through the annular gap into the funnel element has an inlet velocity, at least in operating points of the internal combustion engine above partial load, which is greater than a velocity at which the injector sprays the reducing agent spray jet.

6. The reducing agent addition and preparation system of claim 1 , wherein the injector sprays an at least approximately conically expanding reducing agent spray jet into the exhaust gas, a widening angle of the reducing agent spray jet at least approximately corresponding to the widening angle of the funnel element.

7. The reducing agent addition and preparation system of claim 1 , wherein the widening angle of the funnel element is in a range between 20 degrees and 70 degrees.

8. The reducing agent addition and preparation system of claim 1 , wherein the widening angle of the funnel element is in a range between 30 degrees and 60 degrees.

9. The reducing agent addition and preparation system of claim 1 , wherein exhaust gas flowing through the perforation of the funnel element into the funnel element has an at least approximately perpendicular orientation with respect to an enveloping surface of the reducing agent spray jet cone of the reducing agent spray jet sprayed by the injector.

10. The reducing agent addition and preparation system of claim 1 , wherein the funnel element is situated at least predominantly in an interior of the mixing tube, the funnel element at its widened end inwardly resting against a lateral surface of the mixing tube all the way around or being integrally joined or connected in a positive-fit manner to the mixing tube.

11. The reducing agent addition and preparation system of claim 1 , further comprising:
an exhaust gas guide element configured to direct a first portion of exhaust gas flowing in a direction of the first mixing tube end to the perforated lateral surface of the funnel element, and a second portion in the direction of a portion of the perforated lateral surface of the mixing tube that is downstream from the funnel element.

12. The reducing agent addition and preparation system of claim 1 , further comprising:
an exhaust gas conducting element bent in the shape of a knee with a first leg on an inflow side, and a second leg, adjoining the first leg, on an outflow side, wherein the mixing tube extends from a deflection area from the first leg to the second leg into the second leg and is situated concentrically with respect to the second leg.

13. The reducing agent addition and preparation system of claim 12 , wherein an inflow-side end of the first leg includes a first separating point for attaching an exhaust gas supply pipe, and an outflow-side end of the second leg includes a second separating point for connecting an exhaust gas discharge pipe.

14. The reducing agent addition and preparation system of claim 13 , wherein the mixing tube extends beyond the second separating point from the exhaust gas conducting element bent in the shape of a knee.

15. The reducing agent addition and preparation system of claim 13 , wherein a swirl-forming plate part is provided for the exhaust gas supply pipe.

16. The reducing agent addition and preparation system of claim 12 , wherein the exhaust gas conducting element bent in the shape of a knee has an exterior thermally insulating shell, at least in sections.

17. The reducing agent addition and preparation system of claim 1 , further comprising:
a flange part, to which the mixing tube and the reducing agent metering unit are fastened, and to which at least one cooling plate for dissipating heat from the flange part to surroundings is also fastened, on the outer side with respect to the exhaust gas tract.

18. The reducing agent addition and preparation system of claim 17 , further comprising:
a first and a second cooling plate, wherein the first and second cooling plates being in heat transfer contact with one another via a heat transfer plate, and are held at a distance from one another by the heat transfer plate.

Assignees

• Daimler Ag

Inventors

• Petry Andreas

Classifications

• F01N3/2006

  Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating (by electrically controlling the supply of combustible mixture or its constituents only F02D41/0235) · CPC title

• F01N2900/00

  Details of electrical control or of the monitoring of the exhaust gas treating apparatus · CPC title

• F01N13/14

  having thermal insulation {(exhaust manifolds F01N13/102)} · CPC title

• F01N2260/20

  for heat or sound protection, e.g. using a shield or specially shaped outer surface of exhaust device · CPC title

• F01N3/2066 Primary

  Selective catalytic reduction [SCR] · CPC title