Patent Application
20200102873
The subject disclosure relates to internal combustion engines, and more particularly, to exhaust after treatment systems of internal combustion engines.
Manufacturers of internal combustion engines, more particularly diesel engines, are presented with the challenging task of complying with current and future emission standards for the release of nitrogen oxides, particularly nitrogen oxides (NOx), as well as unburned and partially oxidized hydrocarbons, carbon monoxide, and particulate matter. In order to reduce the constituent emissions of a diesel engine, an exhaust gas after treatment system is used to reduce exhaust constituents within the exhaust gas flowing from the engine.
Exhaust gas after treatment systems typically include one or more after treatment devices, such as oxidation catalysts, catalytic converters, and emissions fluid injectors. Emissions fluid injectors for diesel engines (also called diesel emissions fluid injectors or DEF injectors) may inject a urea or other suitable ammonia based fluid into the exhaust flow to improve the performance of catalytic converters. Further, mixer elements are sometimes used to facilitate urea and exhaust gas mixing to improve catalytic converter operation.
In many systems, a distance along the exhaust gas path between the DEF injector and the catalytic converter is short due to packaging constraints. As such, a low vaporization of the liquid is experienced, which lowers the efficiency of the exhaust gas after treatment system, and reduces durability of the system due to crystallization of the liquid.
In one embodiment, a mixer element of an exhaust treatment apparatus for an internal combustion engine includes a semi-tube having a closed first end and an open second end. The first end includes a fluid inlet configured for connection to an emission fluid injector of the exhaust treatment apparatus. The semi-tube is configured to induce swirl into an exhaust gas flow across the semi-tube. A plurality of bladed discs are spaced axially apart along a tube axis of the semi-tube. The plurality of bladed discs are configured and positioned to induce a helical component to the exhaust gas flow relative to the tube axis. Each bladed disc includes a plurality of blades extending from a disc hub.
Additionally or alternatively, in this or other embodiments the blades of axially adjacent bladed discs are circumferentially offset thereby inducing the helical component to the exhaust gas flow.
Additionally or alternatively, in this or other embodiments the blades of axially adjacent bladed discs are circumferentially offset by an offset angle of between 1 degree and 45 degrees.
Additionally or alternatively, in this or other embodiments the blades of axially adjacent bladed discs are circumferentially offset to obscure a tube passage of the semi-tube in a plane perpendicular to the tube axis.
Additionally or alternatively, in this or other embodiments the bladed discs are secured to the semi-tube.
Additionally or alternatively, in this or other embodiments the plurality of bladed discs is between 2 and 6 bladed discs.
Additionally or alternatively, in this or other embodiments each bladed disc has three blades.
Additionally or alternatively, in this or other embodiments the semi-tube has a circumferential open angle defined between a first circumferential end of the semi-tube and a second circumferential end of the semi-tube.
Additionally or alternatively, in this or other embodiments the circumferential open angle is in the range of 160 degrees to 180 degrees.
Additionally or alternatively, in this or other embodiments the semi-tube includes a plurality of tube perforations.
In another embodiment, an exhaust treatment apparatus for an internal combustion engine includes an exhaust gas pathway, a catalytic converter positioned along the exhaust pathway, and an emission fluid injector positioned along the exhaust pathway configured to inject an emission fluid into the exhaust pathway upstream of the catalytic converter. A mixer element is configured to mix the emission fluid with an exhaust gas flow in the exhaust pathway and includes a semi-tube having a closed first end and an open second end. The first end includes a fluid inlet configured for connection to the emission fluid injector of the exhaust treatment apparatus. The semi-tube is configured to induce swirl into the exhaust gas flow across the semi-tube. A plurality of bladed discs are spaced axially apart along a tube axis of the semi-tube. The plurality of bladed discs are configured and positioned to induce a helical component to the exhaust gas flow relative to the tube axis. Each bladed disc includes a plurality of blades extending from a disc hub.
Additionally or alternatively, in this or other embodiments the blades of axially adjacent bladed discs are circumferentially offset thereby inducing the helical component to the exhaust gas flow.
Additionally or alternatively, in this or other embodiments the blades of axially adjacent bladed discs are circumferentially offset by an offset angle of between 1 degree and 45 degrees.
Additionally or alternatively, in this or other embodiments the blades of axially adjacent bladed discs are circumferentially offset to obscure a tube passage of the semi-tube in a plane perpendicular to the tube axis.
Additionally or alternatively, in this or other embodiments the bladed discs are secured to the semi-tube.
Additionally or alternatively, in this or other embodiments the plurality of bladed discs is between 2 and 6 bladed discs.
Additionally or alternatively, in this or other embodiments each bladed disc has three blades.
Additionally or alternatively, in this or other embodiments the semi-tube has a circumferential open angle defined between a first circumferential end of the semi-tube and a second circumferential end of the semi-tube.
Additionally or alternatively, in this or other embodiments the circumferential open angle is in the range of 160 degrees to 180 degrees.
Additionally or alternatively, in this or other embodiments the semi-tube includes a plurality of tube perforations.
The above features and advantages, and other features and advantages of the disclosure are readily apparent from the following detailed description when taken in connection with the accompanying drawings.
Other features, advantages and details appear, by way of example only, in the following detailed description, the detailed description referring to the drawings in which:
The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application or uses. It should be understood that throughout the drawings, corresponding reference numerals may indicate like or corresponding parts and features.
The exhaust after treatment apparatus 110 and fluid supply 125 are operationally coupled to and controlled by engine controller 106. The engine controller 106 collects information regarding the operation of the internal combustion engine 102 from sensors 128a-128n, such as temperature (intake system, exhaust system, engine coolant, ambient, etc.), pressure, exhaust flow rates, NOx concentrations and, as a result, may adjust the amount of fluid injected into mixer element 122. As used herein the term controller refers to an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated or group) and memory that executes one or more software or firmware programs, a combinational logic circuit, and/or other suitable components that provide the described functionality. As depicted, fluid supply 125 is used in catalytic reduction reactions to reduce constituents in exhaust gases. Fluid supply 125 may include any suitable fluid that can be mixed with exhaust gas from internal combustion engines for the purpose of emission reduction, such as a urea solution for NOx emission reduction and/or hydrocarbons for diesel particulate filter regeneration. In an exemplary exhaust after treatment apparatus 110, the fluid supply 125 includes a water-based urea solution injected into the exhaust gas 118. The ammonia produced by hydrolysis of the urea reacts with the nitrogen oxide emissions and is converted into nitrogen and water within the catalytic converter 124, thereby reducing exhaust gas emissions of the internal combustion engine 102.
Referring to
Referring now to the end view of
Referring now to
Referring now to the end view of
While the above disclosure has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from its scope. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiments disclosed, but will include all embodiments falling within the scope thereof
