MIXER DEVICE FOR AN EXHAUST GAS AFTERTREATMENT SYSTEM OF A MOTOR VEHICLE, EXHAUST GAS AFTERTREATMENT SYSTEM, AND MOTOR VEHICLE

Abstract

A mixer device for an exhaust gas aftertreatment system of a motor vehicle includes a cylindrical housing that has a lateral wall in which there is an injection opening for an exhaust gas aftertreatment medium, a first end wall in which at least one inlet opening is formed, and a second end wall in which an outlet opening is formed; at least one air guiding element situated in the housing, that extends in curved a manner, and that guides an exhaust gas flow from the at least one inlet opening to the outlet opening; and at least one impact surface for the exhaust gas flow and/or the exhaust gas aftertreatment medium situated in the housing downstream from the inlet opening and oriented essentially perpendicularly to the injection direction of the exhaust gas aftertreatment medium.

Claims

1-10. (canceled)

11. A mixer device for an exhaust gas aftertreatment system of a motor vehicle, the mixer device comprising: a cylindrical housing that includes: a lateral wall in which there is an injection opening for an exhaust gas aftertreatment medium; a first end wall in which there is at least one inlet opening; and a second end wall in which there is an outlet opening; at least one air guiding element that is situated in the housing, extends in a curved manner, and guides an exhaust gas flow from the at least one inlet opening to the outlet opening; and situated in the housing downstream from the inlet opening, at least one impact surface for the exhaust gas flow or the exhaust gas aftertreatment medium that is oriented essentially perpendicularly to an injection direction of the exhaust gas aftertreatment medium.

12. The mixer device of claim 11, further comprising at least one further air guiding element situated in the housing downstream from the inlet opening, parallel to the air guiding element, wherein at least one laterally projecting impact element projecting from the at least one further air guiding element forms the impact surface.

13. The mixer device of claim 12, wherein the at least one laterally projecting impact element includes a plurality of impact elements, each of which includes a respective one of the at least one impact surface.

14. The mixer device of claim 12, wherein each of the at least one laterally projecting impact element is an impact tab bent out of the at least one further air guiding element.

15. The mixer device of claim 11, wherein the at least one inlet opening includes a plurality of inlet openings.

16. The mixer device of claim 11, wherein the first end wall includes a section that extends in parallel to the injection direction and is designed without openings.

17. The mixer device of claim 16, further comprising at least one further air guiding element situated in the housing downstream from the inlet opening, parallel to the air guiding element, wherein: at least one laterally projecting impact element projecting from the at least one further air guiding element forms the impact surface; and the section begins at a level of the injection opening and ends spaced apart from the at least one further air guiding element.

18. The mixer device of claim 11, wherein the outlet opening is eccentrically situated or formed in the second end wall.

19. An exhaust gas aftertreatment system for a motor vehicle, the system comprising at least one mixer to which an exhaust gas flow of an internal combustion engine and a liquid exhaust gas aftertreatment medium are routable, wherein each of the at least one mixer includes: a cylindrical housing that includes: a lateral wall in which there is an injection opening for the exhaust gas aftertreatment medium; a first end wall in which there is at least one inlet opening; and a second end wall in which there is an outlet opening; at least one air guiding element that is situated in the housing, extends in a curved manner, and guides the exhaust gas flow from the at least one inlet opening to the outlet opening; and situated in the housing downstream from the inlet opening, at least one impact surface for the exhaust gas flow or the exhaust gas aftertreatment medium that is oriented essentially perpendicularly to an injection direction of the exhaust gas aftertreatment medium.

20. A motor vehicle comprising: an internal combustion engine; and an exhaust gas aftertreatment system that includes at least one mixer to which an exhaust gas flow of the internal combustion engine and a liquid exhaust gas aftertreatment medium are routable, wherein each of the at least one mixer includes: a cylindrical housing that includes: a lateral wall in which there is an injection opening for the exhaust gas aftertreatment medium; a first end wall in which there is at least one inlet opening; and a second end wall in which there is an outlet opening; at least one air guiding element that is situated in the housing, extends in a curved manner, and guides the exhaust gas flow from the at least one inlet opening to the outlet opening; and situated in the housing downstream from the inlet opening, at least one impact surface for the exhaust gas flow or the exhaust gas aftertreatment medium that is oriented essentially perpendicularly to an injection direction of the exhaust gas aftertreatment medium.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 shows a top view of a mixer device for an exhaust gas aftertreatment system of a motor vehicle, according to an example embodiment of the present invention.

[0017] FIG. 2 shows a perspective representation of the mixer device, according to an example embodiment of the present invention.

DETAILED DESCRIPTION

[0018] FIG. 1 shows, in a simplified top view, a mixer device 1 for an exhaust gas aftertreatment system of a motor vehicle, which is not represented here in greater detail. Mixer device 1 is situatable, in particular, fluidically, between an oxidation catalytic converter and an SCR catalytic converter or an SCR-coated particulate filter downstream from an internal combustion engine and is utilized for optimally mixing an exhaust gas aftertreatment medium with the exhaust gas flow of the internal combustion engine, so that an advantageous reduction of nitrogen oxides can take place in the downstream SCR catalytic converter.

[0019] FIG. 2 shows a perspective representation of mixer device 1, upstream oxidation catalytic converter 2 and downstream SCR catalytic converter 3 or the SCR-coated particulate filter being indicated using dashed lines.

[0020] Mixer device 1 includes a housing 4 which includes a lateral wall 5 extending circularly in this case, a first end wall 6, and a second end wall 7. End walls 6 and 7 are aligned in parallel to each other and are spaced apart from each other in accordance with the height of lateral wall 5. Housing 4 is designed in the shape of a cylinder in this regard.

[0021] First end wall 6 includes multiple inlet openings 8, 9, and 10. Inlet opening 8 is optionally designed in the shape of a circle in this case, inlet openings 9 are designed in the shape of a wedge, and inlet opening 10 is designed in the shape of a circle segment. The placement and design of inlet openings 8, 9, and 10 will be discussed in greater detail further below.

[0022] Lateral wall 5 includes an injection opening 11 for liquid exhaust gas aftertreatment medium, injection opening 11 being formed on the end of an injection nozzle 12. Injection nozzle 12 is utilized, for example, for accommodating an injection valve, so that a metered injection of the exhaust gas aftertreatment medium takes place, with the aid of the injection valve, directly at mixer device 1. Nozzle 12 is oriented, in this case, in such a way that the liquid exhaust gas aftertreatment medium is injected into housing 4 in the direction of a secant.

[0023] First inlet opening 8 is situated approximately upstream from inlet opening 11 in this case, and inlet openings 9 begin approximately at the level of injection opening 11 and extend essentially in parallel to the injection direction, their inner width expanding in this case, whereby the aforementioned wedge shape results. The two inlet openings 9 are positioned inversely with respect to each other in this case, so that a section 13, which is designed without openings, lies between them. This section 13 extends from injection opening 11 up to inlet opening 10 in end wall 6. By way of section 13, it is ensured that the exhaust gas flow does not impact the injected exhaust gas aftertreatment medium directly perpendicularly, whereby the exhaust gas flow would push the injected medium flow aside in this area or would deflect the injected medium flow against end wall 7 of housing 2.

[0024] An air guiding element 14 is also situated in housing 4, which extends helically and eccentrically in housing 4, so that the exhaust gas flow and the injected aftertreatment medium is guided to an outlet opening 15 eccentrically formed in end wall 7. Due to the helical shape, the flow path in housing 4 is maximized. According to the present exemplary embodiment, air guiding element 14 extends semicircularly along the outer contour of circular outlet opening 15. Air guiding element 14 begins at lateral wall 5 in this case, whereby the helical course results. The exhaust gas aftertreatment medium and the exhaust gas flow initially impact the outer side of air guiding element 14 and, thereafter, are routed through lateral wall 5 to the inside of air guiding element 14, which routes the flow to outlet opening 15. A swirl results in the exhaust gas-exhaust gas aftertreatment medium mixture in this case, as indicated by an arrow 16.

[0025] In this case, situated in parallel to air guiding element 14 are two further air guiding elements 17 and 18, which are designed to be shorter than air guiding element 14 and extend along a peripheral line, the radius of which has the same origin as the radius of air guiding element 14.

[0026] Further air guiding elements 17, 18 each includes multiple laterally projecting impact elements 19. Impact elements 19 each forms an impact surface 20 that faces injection opening 11. Impact elements 19 are oriented, in this case, in such a way that impact surfaces 20 lie essentially perpendicularly to the injection direction of the exhaust gas aftertreatment medium. In this case, impact elements 19 are designed as impact tabs which are bent out of further air guiding elements 17, 18. Further air guiding elements 17, 18 are formed, in this regard, as one piece with particular impact elements 19. Further air guiding elements 17, 18 can be produced, for example, as stamped and bent sheet-metal parts.

[0027] Further air guiding elements 17, 18 are situated, in areas, at the level of inlet opening 10, so that exhaust gas flowing in through inlet opening 10 can directly impact air guiding elements 17, 18.

[0028] During operation, the exhaust gas flow is therefore introduced into housing 4 through inlet openings 8, 9, and 10, while the exhaust gas aftertreatment medium is injected into housing 4 through injection opening 11. Due to advantageous section 13, the injected exhaust gas aftertreatment medium reaches impact surfaces 20 and atomizes there and is advantageously mixed with the exhaust gas flow which is also flowing in. Due to air guiding element 14 and the extension of air guiding elements 17, 18, the exhaust gas flow-exhaust gas aftertreatment medium mixture is routed along lateral wall 5 and air guiding element 14 to outlet opening 15, whereby swirl 16 results. Due to swirl 16, the downstream SCR catalytic converter or SCR-coated particulate filter is advantageously acted upon, so that an advantageous exhaust gas aftertreatment results.

[0029] Advantageous mixer device 1 has the advantage of an installation space-saving design including a long flow path which provides for advantageous mixing. In addition, an advantageous atomization of the exhaust gas aftertreatment medium is ensured. The placement of one or multiple sensors on the mixer device, in particular, upstream from the mixing area, is easily possible in order to monitor the exhaust gas aftertreatment. The injection valve is easily and cost-effectively situatable on housing 4 or on mixer device 1. Mixer device 1 provides for the maximum utilization of the thermal energy of the exhaust gas flow onto the impact surfaces and further air guiding elements 17, 18, whereby the robustness of the mixer device with respect to the exhaust gas aftertreatment medium is enhanced.