Multi-cell structure for automotive catalyst support
An exhaust system is described including an exhaust manifold having different length runners, with an emission control device housing a plurality of catalyst bricks, at least one of which having a multi-cell density. In this way, uneven exhaust mixing may be addressed without modifying packaging of the exhaust system.
1. An exhaust system, comprising:
an exhaust manifold having different length runners, the runners joining in a mixing area within the exhaust manifold; and
an emission control device housing a catalyst brick with a varying multi-cell density within the catalyst brick varying across and at a front face of the catalyst brick, cells with higher and lower density each having walls that support a coating of metal catalysts within the catalyst brick,
wherein a first catalyst brick in a housing has the varying multi-cell density and a second catalyst brick in the housing has a uniform cell density.
2. The exhaust system of claim 1 , wherein the emission control device is in a close-coupled position, and wherein the varying multi-cell density is defined as a number of cells per unit of cross-sectional area.
3. The exhaust system of claim 1 , further comprising another emission control device positioned downstream of the emission control device, and an exhaust sensor positioned between the emission control devices.
4. The exhaust system of claim 1 , wherein an average cell density of a first catalyst brick differs from an average cell density of a second catalyst brick in the housing, and further comprising an exhaust gas sensor positioned between the first and second catalyst bricks.
5. The exhaust system of claim 1 , wherein the exhaust manifold includes exactly three runners, with one longer than the remaining two runners, the one longer runner being positioned at one end of the exhaust manifold opposite the remaining two, and wherein an open frontal area of the catalyst brick varies based on the varying multi-cell density.
6. The exhaust system of claim 5 , further comprising an oxygen sensor positioned adjacent the one longer runner.
7. An exhaust system, comprising:
an engine having an integrated exhaust manifold having different length exhaust runners; and
an emission control device housing a plurality of catalyst bricks serially positioned, with varying cell density within a catalyst brick at a front face of the catalyst brick, cells with higher and lower density each having walls that support a coating of metal catalysts within the catalyst brick at the front face of the catalyst brick,
wherein the catalyst bricks are positioned linearly within the exhaust system,
wherein the plurality of catalyst bricks has varying cell density,
wherein the varying cell density is in a vertical direction, and
wherein there is a larger variation in cell density within a vertical center region in a first catalyst brick than a second catalyst brick, while there is a larger variation in cell density within a vertical bottom region in the second catalyst brick than the first catalyst brick, wherein the vertical direction is a direction orthogonal to a longitudinal axis of the emission control device.
8. The exhaust system of claim 7 , wherein the emission control device is in a close-coupled position, and wherein the exhaust manifold includes exactly three runners, with one longer than the remaining two runners, the one longer runner being positioned at one end of the exhaust manifold opposite the remaining two, and wherein one runner is wider than the remaining two runners.
9. The exhaust system of claim 7 , further comprising another emission control device positioned downstream of the emission control device.
10. The exhaust system of claim 7 , wherein a first, upstream, brick has varying cell density along only one direction, the one direction being one of horizontal or vertical, wherein the vertical direction is a direction orthogonal to a longitudinal axis of the emission control device, and the horizontal direction is a direction orthogonal to both the longitudinal axis and the vertical direction.
11. The exhaust system of claim 7 , wherein a first, upstream, brick has varying cell density along two directions, the two directions being horizontal and vertical, wherein the vertical direction is a direction orthogonal to a longitudinal axis of the emission control device, and the horizontal direction is a direction orthogonal to both the longitudinal axis and the vertical direction.
12. The exhaust system of claim 7 , wherein a first catalyst brick has the varying cell density in a first region of the front face of the catalyst brick and a uniform cell density in a second region of the front face of the catalyst brick, and wherein all catalyst bricks in the plurality of catalyst bricks are positioned on a common longitudinal axis.
13. The exhaust system of claim 8 , further comprising an oxygen sensor positioned adjacent the one longer runner.
14. An exhaust system, comprising:
an exhaust manifold having different length runners, the runners joining in a mixing area within the exhaust manifold; and
an emission control device housing a catalyst brick with a varying multi-cell density within the catalyst brick varying across and at a front face of the catalyst brick, cells with higher and lower density each having walls that support a coating of metal catalysts within the catalyst brick,
wherein an average cell density of a first catalyst brick differs from an average cell density of a second catalyst brick in a housing, and further comprising an exhaust gas sensor positioned between the first and second catalyst bricks.
15. The exhaust system of claim 14 , wherein the emission control device is in a close-coupled position, and wherein the varying multi-cell density is defined as a number of cells per unit of cross-sectional area.
16. The exhaust system of claim 14 , wherein a first catalyst brick in the housing has a first varying multi-cell density and a second catalyst brick in the housing has a second, different, varying multi-cell density.
17. The exhaust system of claim 14 , further comprising another emission control device positioned downstream of the emission control device, and an exhaust sensor positioned between the emission control devices.
18. The exhaust system of claim 14 , wherein the exhaust manifold includes exactly three runners, with one longer than the remaining two runners, the one longer runner being positioned at one end of the exhaust manifold opposite the remaining two, and wherein an open frontal area of the catalyst brick varies based on the varying multi-cell density.
19. The exhaust system of claim 18 , further comprising an oxygen sensor positioned adjacent the one longer runner.