Mixing device of an exhaust gas purification system of a motor vehicle internal combustion engine

Patent metadata

Field	Value
Publication number	US-10196957-B2
Application number	US-201515318923-A
Country	US
Kind code	B2
Filing date	Mar 26, 2015
Priority date	Jun 17, 2014
Publication date	Feb 5, 2019
Grant date	Feb 5, 2019

Abstract

A mixing device of an exhaust gas purification system of an internal combustion engine is disclosed. The mixing device includes swirl tube, a mixing tube arranged in the swirl tube, and an exhaust gas supply tube leading into the swirl tube such that exhaust gas can enter the swirl tube tangentially from the exhaust gas supply tube through a cut-out opening in the lateral surface of the swirl tube and forms a flow rotating around the mixing tube. The exhaust gas completely enters the mixing tube and leaves the interior of the swirl tube completely through the mixing tube. A metering device can spray urea solution into the swirl tube such that the urea solution enters the mixing tube and is entrained by the rotating flow of the exhaust gas and is discharged from the swirl tube through the mixing tube together with the exhaust gas.

First claim

The invention claimed is:

1. A mixing device of an exhaust gas purification system of a motor vehicle internal combustion engine for mixing urea solution with exhaust gas of the motor vehicle internal combustion engine, comprising:
a straight circular cylindrical swirl tube which has a first end and a second end opposite the first end and a lateral surface having a cut-out opening;
a circular cylindrical mixing tube which is disposed in the swirl tube in some sections and coaxially to the swirl tube, wherein the mixing tube has an open first end disposed inside the swirl tube and penetrates a bottom part of the second end of the swirl tube and wherein the mixing tube has a completely closed lateral surface such that the exhaust gas can only enter the mixing tube at the open first end of the mixing tube;
an exhaust gas supply tube, at least approximately tangentially entering the swirl tube such that the exhaust gas can enter from the exhaust gas supply tube through the cut-out opening in the lateral surface of the swirl tube at least approximately tangentially into the swirl tube and forms a flow rotating around the mixing tube after the exhaust gas has entered the swirl tube, wherein the exhaust gas, while maintaining a rotating flow, completely enters the open first end of the mixing tube and leaves an interior of the swirl tube completely through the mixing tube;
a metering device disposed at the first end of the swirl tube, wherein urea solution is sprayable into the swirl tube by the metering device with a conical spraying pattern such that the urea solution at least approximately completely enters the open first end of the mixing tube and is entrained by the rotating flow of the exhaust gas and is discharged from the interior of the swirl tube through the mixing tube together with the exhaust gas; and
a funnel element which conically opens in a direction of the open first end of the mixing tube, wherein the funnel element has a cone axis which is at least approximately collinear with a swirl tube axis and wherein the urea solution is at least approximately completely sprayable by the metering device into the funnel element.

2. The mixing device according to claim 1 , wherein a conical lateral surface of the funnel element is perforated.

3. The mixing device according to claim 1 , wherein the funnel element has a cylindrical circular opening at a pointed end of the funnel element.

4. The mixing device according to claim 1 , wherein the exhaust gas supply tube has at a junction with the swirl tube an axially expanding cross-sectional enlargement with respect to the swirl tube.

5. The mixing device according to claim 1 , wherein the cutout opening extends along a longest dimension of the cutout opening, with respect to a swirl tube axis, from a first portion near the second end of the swirl tube to a second portion close to the open first end of the mixing tube.

6. The mixing device according to claim 1 , wherein a cross-sectional area of the mixing tube at least approximately corresponds to a smallest cross-sectional area of the exhaust gas supply tube.

7. The mixing device according to claim 1 , wherein a difference of a cross-sectional area of the swirl tube and a cross-sectional area of the mixing tube is at least 30 percent greater than a smallest cross-sectional area of the exhaust gas supply tube.

8. The mixing device according to claim 1 , further comprising an enclosing tube with a perforated lateral surface, wherein the funnel element is received within the enclosing tube.

9. The mixing device according to claim 1 , further comprising a flow baffle having arms which open, at least approximately, in a direction of the second end of the swirl tube, wherein the arms are connected along a first profile line with a form fit with a lateral surface of the mixing tube, wherein the arms have along a second profile line at least approximately touching contact with the lateral surface of the swirl tube, and wherein a connecting line of the arms is at least approximately oriented in a direction which is parallel to a longitudinal direction of the exhaust gas supply tube.

Assignees

• Daimler Ag

Inventors

• Petry Andreas

Classifications

• B01F3/04049

  Operations & Transport · mapped topic

• F01N3/2892 Primary

  Exhaust flow directors or the like, e.g. upstream of catalytic device · CPC title

• F01N2240/20

  a flow director or deflector · CPC title

• B01F5/0451

  Operations & Transport · mapped topic

• Y02A50/2322

  Cross-Sectional Technologies · mapped topic