Exhaust system including an exhaust manifold having an integrated mixer plate

1. An exhaust system, comprising:

a 3-way catalyst;

an exhaust manifold having an outlet directly coupled to the 3-way catalyst and a plurality of runners merging at a confluence section positioned upstream of the 3-way catalyst; and

a mixer plate positioned in the confluence section, the mixer plate including a central opening and a plurality of louvered vents positioned axially around the central opening, the louvered vents having angled openings facing a common rotational direction.

2. The exhaust system of claim 1 , where the louvered vents extend in an upstream direction.

3. The exhaust system of claim 1 , where the louvered vents extend in a downstream direction.

4. The exhaust system of claim 1 , where the louvered vents extend in a downstream direction and an upstream direction.

5. The exhaust system of claim 1 , where openings defined by the louvers do not extend in a radial direction.

6. The exhaust system of claim 1 , further comprising an exhaust gas sensor extending into the central opening.

7. The exhaust system of claim 1 , where an inlet of the central opening is positioned upstream of the louvered vents.

8. The exhaust system of claim 1 , where the louvered vents are curved in an axial direction.

9. The exhaust system of claim 1 , where a width of the openings in an axial direction is greater than 3 mm.

10. The exhaust system of claim 1 , where a ratio between a diameter of the central opening and an outer diameter of the mixer plate is 0.3 to 0.9.

11. The exhaust system of claim 1 , where the louvered vents form an angle with a tangent line to an outer surface of the mixer plate which is 45 to 135 degrees.

12. The exhaust system of claim 1 , where the louvered vents are not equivalent in at least one of size and geometry.

13. The exhaust system of claim 1 , wherein the mixing plate includes an outer peripheral surface positioned within and directly coupled to an outlet of the exhaust manifold.

14. A method for operating an exhaust system coupled to an engine, comprising:

flowing exhaust gas from a plurality of exhaust runners in an exhaust manifold to a confluence section in the exhaust manifold where the plurality of exhaust runners merge;

flowing exhaust gas through a mixer plate spanning the confluence section and including a central opening and louvered vents positioned axially around the central opening, the louvered vents having angled openings facing a common rotational direction, an exhaust gas sensor extending through the central opening; and

flowing exhaust gas from the mixer plate to a 3-way catalyst directly downstream of the mixer plate.

15. The method of claim 14 , where the louvered vents extend in an axial direction.

16. An exhaust system for an engine, comprising:

a 3-way catalyst;

an exhaust manifold having a plurality of runners merging at a confluence section positioned directly upstream of the 3-way catalyst; and

a mixer plate extending across the confluence section, the mixer plate including a central opening and louvered vents positioned axially around the central opening, the louvered vents having angled openings facing a common rotational direction.

17. The exhaust system of claim 16 , where the mixer plate and an exhaust manifold housing comprise different materials.

18. The exhaust system of claim 16 , where the louvered vents are curved in an axial direction.

19. The exhaust system of claim 16 , where the mixer plate is axially aligned with a central axis of the 3-way catalyst.