Engine emission control system
AssigneeFord Global Technologies, LLC
InventorsJeong Yeol Kim, Giovanni Cavataio
Life of this patent
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Abstract
Systems and methods are provided for reducing exhaust NOx species using a monolith substrate having a plurality of channels configured with radially varying cell density. An injector injects reductant into the substrate unobstructedly, without use of a mixer. In some embodiments, a twist angle of the channels is based on a distance from an inlet of the substrate and varies exponentially as a function of the distance.
Claims14
A method of operating an emission control system coupled to an exhaust passage of an engine, comprising:
- injecting an amount of reductant upstream of a first monolithic cylindrical substrate having a plurality of channels of radially varying cell density, the radial variation including inner channels with a higher cell density and outer channels with a lower cell density, the injected amount of reductant flowing unobstructedly from an injector into the first substrate without use of a mixer;
- flowing exhaust gas through the first substrate to mix the exhaust gas with the injected reductant;
- and
- flowing the mixed exhaust gas over an SCR catalytic washcoat to catalytically convert a component of the mixed exhaust gas,
- wherein the channels are along a length of the first substrate, and wherein the channels are rotated progressively along a lateral axis along the length of the first substrate, a twist angle of the rotation varying exponentially as a function of a distance from an inlet of the first substrate.
An emission control system of an engine exhaust passage, comprising:
- a monolithic-substrate having channels of varying cell density extending from an inlet end to an outlet end of the monolithic-substrate with a channel twist angle varying exponentially as a function of monolithic-substrate length;
- a downstream-substrate;
- an upstream injector to inject reductant to flow unobstructedly to the monolithic-substrate without use of a mixer via an upstream reductant injector;
- and
- an SCR catalytic washcoat on the monolithic-substrate or on the downstream-substrate.
An emission control system coupled to an exhaust passage of an engine, comprising:
- a monolithic upstream substrate having a plurality of channels of varying cell density, the channels formed within the upstream substrate and having a length extending between an inlet end of the upstream substrate and an outlet end of the upstream substrate, the cell density varying radially through the upstream substrate with a higher cell density at a center of the upstream substrate and a lower cell density at a periphery of the upstream substrate, the channels twisted along the length of the channels, where a twist angle of the channels is based on a distance from the inlet of the upstream substrate and varies exponentially as a function of the distance, and where a position of a selected channel at the inlet end is twisted with respect to a position of the selected channel at the outlet end;
- a reductant injector positioned upstream of the upstream substrate for injecting reductant that flows unobstructedly from the injector to an inlet of the upstream substrate without use of a mixer;
- a downstream substrate having a plurality of channels of uniform cell density;
- and
- an SCR catalytic washcoat coated on the downstream substrate and the upstream substrate.
Dependencies are inferred from the claim text.