Emissions control substrate

An emissions control substrate. The emissions control substrate includes a first end and a second end opposite to the first end. A plurality of channels extend between the first end and the second end, and are configured to direct exhaust from an engine through the substrate. The emissions control substrate is three-dimensionally printed.

FIELD

The present disclosure relates to an emissions control substrate, such as a three-dimensionally printed emissions control substrate.

BACKGROUND

Emissions control substrates are often used with engine exhaust systems to treat the exhaust before it is released into the atmosphere. For example, a catalytic converter substrate is often used with automobile exhaust systems to catalyze a redox reaction, thereby converting CO into CO2, and converting NOxinto N2and O2. A particulate filter substrate is often used to treat exhaust gas from a diesel engine by filtering particulate matter out of the exhaust. While existing emissions control substrates are suitable for their intended use, they are subject to improvement. The present teachings provide for emissions control substrates that address various needs in the art, and provide numerous unexpected and advantageous results.

SUMMARY

The present teachings provide for an emissions control substrate. The emissions control substrate includes a first end and a second end opposite to the first end. A plurality of channels extend between the first end and the second end, and are configured to direct exhaust from an engine through the substrate. The emissions control substrate is three-dimensionally printed.

DETAILED DESCRIPTION

With initial reference toFIG. 1, an emissions control device according to the present teachings is illustrated at reference numeral10. The emissions control device includes an exhaust chamber or shell12having an inlet14and an outlet16on opposite sides thereof. Within the exhaust chamber12is an emissions control substrate20, which can be configured as a catalytic converter and/or a particulate filter, depending on the application. The emissions control device10is configured to be coupled to an exhaust system of an engine, such as any suitable internal combustion engine, including a vehicle engine, generator, building system, etc. With respect to vehicles, the emissions control device10can be used with any suitable vehicle including passenger vehicles, sport utility vehicles, recreational vehicles, military vehicles, mass transit vehicles, locomotives, watercraft, aircraft, etc.

The emissions control device10, and particularly the substrate20thereof, can be formed in any suitable manner, such as with any suitable three-dimensional manufacturing or printing process (also known as additive manufacturing) using any suitable three-dimensional manufacturing device. Any suitable type of three-dimensional manufacturing can be used, such as, but not limited to, the following, which are generally referred to herein as three-dimensional printing: fused deposition modeling; fused filament fabrication; robocasting; stereo lithography; digital light processing; powder bed three-dimensional printing; inkjet head three-dimensional printing; electron-beam melting; selective laser melting; selective heat sintering; selective laser sintering; direct metal laser sintering; laminated object manufacturing; and electron beam freeform fabrication. Any of the substrates20described herein can be manufactured using three-dimensional printing, or any other suitable manufacturing process. The substrates20can be manufactured apart from, or together with, the exhaust chamber12. When manufactured together, three-dimensional printing can be used to manufacture the entire emissions control device10with the substrate20within the chamber12, thereby simplifying manufacturing, assembly, and installation of the emissions control device10, and typically reducing the overall cost of the emissions control device10.

With additional reference toFIG. 2, the substrate20defines a plurality of channels or cells22, which are adjacent to one another and extend between a first end24and a second end26of the substrate20. Each one of the channels22includes a first opening28at the first end24of the substrate20, and a second opening30at the second end26of the substrate20. A body32of each one of the channels22extends from the first opening28to the second opening30. The substrate20is arranged in the chamber12such that exhaust entering the emissions control device10through the inlet14enters the channels22through the first openings28of the channels22. Exhaust passes through the channels22and is treated, as described further herein, and exits the channels22through the second openings30. From the second openings30exhaust flows out of the emissions control device10through the outlet16.

In the example ofFIG. 2, the channels22extend generally linearly from the first end24to the second end26of the substrate20, such that the bodies32of the channels22extend parallel to a longitudinal axis A of the substrate20extending from the first end24to the second end26. Alternatively and with reference toFIG. 3A, the channels22can each be configured with a body34, which does not extend parallel to the longitudinal axis A, but is rather continuously curved along its length from the first end24to the second end26. For example, the bodies34can curve or twist in a generally clockwise or counterclockwise direction along the lengths thereof as the bodies34extend from the first end24to the second end26of the body32. With reference toFIG. 3B, as another alternative the channels22can include a body36with an offset portion38along the lengths thereof. The offset portion38is generally halfway between the first opening28and the second opening30along the lengths of each of the channels22. The offset portion38is curved and generally laterally offset from portions of the body36that are proximate to the first end24and the second end26. The continuously curved body portions34and the body portions36with the offset portions38provide numerous advantages, such as facilitating interaction of exhaust with catalyst(s) present on sidewalls of the channels22and/or facilitating flow of exhaust through exhaust permeable sidewalls60(seeFIG. 6for example) of the channels to filter particulate matter from the exhaust, as described herein.

With reference toFIG. 4, the channels22may be provided with any suitable cross-sectional shape. For example, the channels22may have a generally circular cross-sectional shape40. Other suitable cross-sectional shapes include triangular42, rectangular44, oval46, hexagonal48, etc. Each one of the channels22may have the same cross-sectional shape along its entire length. Alternatively, a particular channel22may have more than one cross-sectional shape along its length. In other words, a single channel22may change in cross-sectional shape along its length. Providing channels22that have different cross-sectional shapes from one another, and providing channels22that vary in cross-sectional shape along lengths thereof, results in numerous advantages. Exemplary advantages include facilitating interaction of exhaust with catalyst(s) present on sidewalls60of the channels22, and/or facilitating flow of exhaust through sidewalls60of the channels22to filter particulate matter from the exhaust, as described herein.

As illustrated inFIG. 5, the substrate20can include a plurality of plugs or walls50within the channels22. Each channel22can include one or more plugs50along the length thereof. The plugs50extend generally perpendicular to the direction of exhaust travel through the channels22and are impermeable to exhaust. Therefore, each plug50blocks the flow of exhaust through the particular channel that the plug50is within. The plugs50are staggered along the length of the substrate20such that channels22in close proximity to one another have plugs50that are at different points along the length of the substrate20. As a result, when exhaust flowing through a particular channel22contacts a plug50, or comes within close proximity to a plug50, the exhaust is forced through the sidewalls of the channel22and into a neighboring channel22. Thus, the plugs50advantageously force exhaust to cross over from one channel22to another channel22through exhaust-permeable sidewalls60separating the channels22. This facilitates flow of exhaust through the sidewalls60of the channels22to filter particulate matter from the exhaust, such as when the substrate20is used as a particulate filter, and/or facilities interaction of exhaust with catalyst(s) present on sidewalls60of the channels22, such as when the substrate20is used as catalytic converter.

FIG. 6is a cross-sectional view of an exemplary one of the channels22, and partially illustrates neighboring channels22on opposite sides thereof. Each channel22is defined by sidewalls60of the substrate20. The sidewalls60can be made of any suitable material. For example, when the substrate20is configured for use as a particulate matter filter, such as a diesel particulate matter filter, the sidewalls60can be made of any material that is suitable to filter (and thus trap therein) particulate matter from exhaust passing through the sidewall60. The particulate matter filtered can be any atmospheric pollutant including hydrocarbons or other chemicals, such as soot, ash, dust, fumes, smog, etc., for example. The sidewalls60can thus include any suitable ceramic material, such as cordierite. The sidewalls60can be formed using any suitable three-dimensional printing technique, as described above.

The sidewalls60can have an outer metallic layer62. The outer metallic layer62can include any suitable metal, such as any suitable precious metal. When the substrate20is used as a catalytic converter, the metallic layer62can include any catalyst suitable for catalyzing a redox reaction to treat toxic pollutants in exhaust gas prior to release of the exhaust to the atmosphere. For example, the catalyst can be any catalyst suitable to convert carbon monoxide, hydrocarbons, and nitrogen oxides to carbon dioxide, water vapor, and nitrogen gas, for example. When the substrate20is used as a diesel particulate filter, the metallic layer62can be any catalyst suitable for regenerating the substrate20by reducing the ignition temperature necessary to oxidize particulate matter that has accumulated on or in the sidewalls60. Exemplary catalysts include, but are not limited to, platinum, palladium, rhodium, cerium, iron, manganese, nickel, and copper.

The metallic layer62can be provided on the sidewall60in any suitable manner. For example, the metallic layer62can be three-dimensionally printed on the sidewall60as the sidewall60is being printed, or the metallic layer62can be printed on the sidewall60after the sidewall60has been printed or otherwise formed. Metallic layer62can be directly printed on the sidewall60, so as to eliminate any need for an intermediate layer or washcoat for example. Alternatively and as illustrated inFIG. 7, a transition zone or layer64can be included between the sidewall60and the metallic layer62. The transition zone64can be a carrier for the metallic layer62, such as a washcoat, and can be made of any suitable material. For example, the transition zone64can include a mixture of the ceramic of the sidewall60and the metal of the metallic layer62. As a washcoat, the transition zone64can include any suitable material for suspending the metallic layer62, such as, but not limited to, the following: aluminum oxide; titanium dioxide; silicon dioxide; and a mixture of silica and alumina. The transition zone64can be applied to the sidewall60in any suitable manner, such as by three-dimensional printing.

With reference toFIG. 8, the sidewalls60can define particulate matter traps70extending between channels22, which are configured to trap particulate matter therein as exhaust gas flows through the channels22from one channel22to a neighboring channel22. The particulate matter traps70can be configured to trap any type of particulate matter, such as soot, ash, dust, fumes, smog, etc., for example. The particulate matter traps70extend through the metallic layer62(when included), and can extend completely or partially through the sidewall60. Any suitable number of particulate matter traps70can be provided through any suitable number of the channels22. The particulate matter traps70can be formed in any suitable manner. For example, the particulate matter traps70can be defined between the sidewalls60as the sidewalls60are printed, or can be formed within the sidewalls60after printing, such as with a laser punch80for example.

With reference toFIG. 9, the sidewalls60can be provided with a heating element90therein. As exhaust flows through the sidewall60, the exhaust will flow around the heating element90in order to heat the exhaust. The heating element90can be any suitable heating element. For example, the heating element90can be an electrode connected to a current source, such as a battery92. The heating element90can be provided within the sidewall60in any suitable manner, such as during three-dimensional printing of the sidewall60. Thus, the sidewall60and the heating element90can be advantageously printed together. When the substrate20is used as a diesel particulate filter, the heating element90can be used to facilitate regeneration. For example, raising the temperature of the sidewall60to about 600° C. or higher facilitates oxidization of carbon-rich particulate matter, and results in the particulate matter being burned-off in order to clean the substrate20. Heating the sidewalls60can also facilitate the redox reaction when the substrate20is used as a catalytic converter, particularly when the engine is started at cold temperatures.

FIG. 10illustrates a fluid flow path110defined within the sidewalls60. The fluid flow path110can be formed within the sidewalls60in any suitable manner, such as during three-dimensional printing of the sidewalls60. The fluid flow path110can be formed to flow through any suitable number of the sidewalls60, and can be configured to permit any suitable fluid to flow therethrough. For example, any suitable liquid that can be warmed, such as warming oil, can be provided within the fluid flow path110to facilitate regeneration of the substrate20and/or facilitate the redox reaction of a catalytic converter. As exhaust flows through the sidewall60, the exhaust will flow around the fluid flow path110with the warming oil or other suitable warming liquid, in order to heat the exhaust. The fluid flow path110can also include any suitable reductant to facilitate the redox reaction in a catalytic converter, such as a urea solution. Contents of the fluid flow path110can be added during the three-dimensional printing process forming the sidewall60, or after the sidewall60has been formed by spraying or injecting the liquid into an inlet of the fluid flow path110.