Patent Application
20250043711
The present application relates generally to exhaust treatment systems. More particularly, the present application relates to aftertreatment apparatuses, systems and methods for treatment of exhaust from diesel engines and to techniques for varying the capture of diesel particles and controlling nitrogen gas and other emissions.
Waterborne vessels and, in particular, large waterborne vessels are often powered by diesel engines. In some cases, the power from these diesel engines can be used for propulsion, but the power may also be converted to electricity to provide electric power to other aspects of the vessel.
Emission control regulations continue to evolve and become more stringent as environmental concerns over combustion engine emissions continue to increase. In some areas of the world, emission controls may be lower for waterborne vessels as compared with European Union or other jurisdictions. These emission restrictions can relate to particle numbers and/or nitrogen gas emissions.
Korean Patent No. 101491350, U.S. Pat. No. 9,797,285 and United States Patent Application Publication No. 2022/0290602 are directed toward diesel aftertreatment systems and apparatuses. However, these patents and patent applications do not address varying the capture of diesel particles and/or controlling emissions in the manner of the present application.
In one or more embodiments, an apparatus for aftertreatment for a diesel engine, optionally including: a housing having an inlet, an outlet and defining a cavity therein; a plurality of tubes mounted within the cavity and arranged to define a multi-flow split arrangement to pass an exhaust flow of the diesel engine through each of the plurality of tubes; and a plurality of treatment units configured to treat the exhaust flow within the housing, wherein each of the plurality of treatment units is coupled within a corresponding one of the plurality of tubes to receive a portion of the exhaust flow. A number of the plurality of treatment units utilized to treat the exhaust flow within the housing is less than a number of the plurality of tubes such that at least one of the plurality of tubes does not contain one of the plurality of treatment units.
In one or more embodiments, an aftertreatment system for a diesel engine, optionally including: a housing configured for placement in fluid communication with the diesel engine to receive an exhaust flow therefrom, the housing includes a plurality of tubes mounted within the housing and arranged to define a multi-flow split arrangement to pass the exhaust flow of the diesel engine through each of the plurality of tubes; and a plurality of treatment units selectively removable and insertable into the plurality of tubes. The plurality of treatment units are configured for treatment of the exhaust flow, and a number of treatment units utilized to treat the exhaust flow within the housing is selectively changeable relative to a number of the plurality of tubes.
In one or more embodiments, a method of aftertreatment of exhaust from a diesel engine, optionally including: receiving an exhaust flow from the diesel engine into an apparatus that defines a multi-flow split arrangement, passing the exhaust flow in parallel through the multi-flow split arrangement, treating the exhaust flow of less than all of the multi-flow split arrangement, recombining the exhaust flow within the apparatus, and passing the exhaust flow from the apparatus.
Referring now to
The DPF 102 can be configured to filter out diesel particulate in an exhaust flow from the diesel engine. For example, the DPF 102 may be configured to filter out soot and ash from the exhaust stream. Moreover, the DPF 102 may be configured for ongoing (e.g., passive) regeneration. In one or more examples, the DPF 102 can include a housing 106 forming a cavity 108 and having an inlet 110 and outlet 112. The DPF 102 can be constructed to define a multi-flow split arrangement 113 for the exhaust flow. The DPF 102 can also include a filtration system 114 within the housing 106 (e.g., arranged in the cavity 108) along one or more of the multi-flow split arrangement 113. The multi-flow split arrangement 113 defines a number of fluid pathways through the DPF 102 from the inlet 110 to the outlet 112. The filtration system 114 may include one or more treatment units (discussed subsequently) such as filter media arranged within one or more of the fluid pathways. The exhaust flow from the diesel engine passes through the one or more of treatment units before exiting the DPF 102. Various constructs for the one or more treatment units and the filtration system 114 are known. An exemplary configuration is discussed herein with the understanding the principles and techniques can be applied to other configurations for the one or more treatment units and the filtration system 114. The one or more of treatment units may have a porosity selected to allow exhaust gas through the filter media while reducing or preventing passage of ash and soot. For purposes discussed herein and for other purposes, the DPF 102 may also include first and second sensors 116/118 such as at the inlet/outlet of the DPF 102, respectively. The sensors 116/118 may be absolute pressure sensors, particulate sensors, emission sensors, combinations thereof, or the like. As an example, the sensors 116/118 can be configured for sensing respective pressures at the inlet/outlet 110/112 such that a differential pressure or pressure drop across the DPF 102 may be calculated or determined.
As mentioned, the DPF 102 may also be configured for ongoing (e.g., passive) regeneration. For example, the DOC 120 may be provided upstream of the DPF 102. The DOC 120 can function to produce nitrogen dioxide (NO2). For example, the DOC 120 may include an oxidation catalyst that functions to absorb oxygen from the exhaust gas providing an opportunity for other elements in the exhaust gas to react with the bonded oxygen. In particular, nitric oxide (NO) may react with the oxygen to form nitrogen dioxide (NO2). When the nitrogen dioxide passes through the one or more treatment units in the DPF 102, the nitrogen dioxide may react with the carbon in the soot to form carbon dioxide (CO2), which may then pass through the one or more treatment units such as filter media. Alternatively or additionally, the DPF 102 may include a catalyst as the one or more treatment units or the one or more treatment units can include a combination of a catalyst and the filter media. The catalyst can function to generate NO2. The NO2 generated in the filter media may back diffuse through the filter media and react with the soot to form CO2, which may pass through the filter media and out of the DPF 102. In either case, some of the NO2 generated either in the DOC 120 or within the filter media of the DPF 102 may not be fully absorbed or utilized in the regeneration process and, as such, the nitrogen oxide gases (NOx) leaving the DPF 102 may be a combination of NO and NO2. It is to be appreciated that while the DOC 120 has been shown outside of the DPF 102, it may also be incorporated therein.
The SCR system 104 can be arranged downstream of the DPF 102. The SCR 104 may be configured to reduce the amount of nitrogen oxide gas (NOx) in the exhaust before it is released into the atmosphere. In particular, the SCR 104 may function to react ammonia (NH3) with NOx in the exhaust gas to produce nitrogen and water and, as such, reduce the emission of NOx. The SCR 104 may include a housing defining an internal cavity and having an inlet and an outlet. The SCR 104 may have a diesel exhaust fluid (DEF) reservoir in fluid communication with the cavity via a controllable valve or nozzle. In one or more examples, the DEF may be in fluid communication with the exhaust stream upstream of the SCR 104 and not directly in the cavity. The SCR 104 may also have one or more of treatment units such as a series of catalysts arranged within the cavity. For example, the SCR 104 may include a hydrolysis catalyst adapted to convert liquid urea to ammonia, for example. The SCR may also include an SCR catalyst to convert the ammonia and NOx to nitrogen and water. The SCR catalysts may include various porous ceramic materials with active catalytic components arranged on the ceramic material. For example, the SCR catalyst may include oxides of base metals such as vanadium, molybdenum, and tungsten, zeolites, or various precious metals may be used. Still other active catalytic components may be used. In one or more examples, the SCR 104 may also include an oxidation catalyst or an ammonia slip catalyst to address any remaining ammonia in the exhaust gas. The SCR 104 may also include an inlet NOx sensor 132 and an outlet NOx sensor 134.
The aftertreatment system 100 may also include a controller 130 that determines, alerts, recommends and/or controls as further discussed herein. For example, the aftertreatment system 100 can include the plurality of sensors (e.g., the sensors 116/118, 132, 134) configured to measure at least a NOx concentration and a diesel particulate concentration in the exhaust flow of the aftertreatment system 100. Additionally, the plurality of sensors (e.g., the sensors 116/118, 132, 134) can be configured to measure other parameters such as pressure, pressure drop, temperature, temperature drop, particulate concentration, soot loading, etc. The controller 130 can be configured to determine/calculate various parameters based upon the data/input from the plurality of sensors. For example, the controller 130 can be configured to determine a NO2 to NO x ratio and a filtration efficiency based upon data from the plurality of sensors. The controller 130 can be configured to compare the NO2 to NO x ratio and the filtration efficiency to governing regulatory standards. The controller 130 can be configured to recommend via a display at least a desired number of the plurality of treatment units that should be utilized with the DPF 102, SCR 104 and/or DOC 120. The controller 130 can be configured to perform other functions as further discussed herein including recommending an orifice size configured to restrict the exhaust flow be installed within one or more of the DPF 102, SCR 104 and/or DOC 120. The controller 130 can be configured to control a valve to adjust to restrict the exhaust flow through the DPF 102, SCR 104 and/or DOC 120. The controller 130 can be configured to determine based upon sensed data at least a pressure drop in the exhaust flow of the aftertreatment system or a soot loading of the plurality of treatment units and displays at least the pressure drop or the soot loading along with the display of the at least the desired number of the plurality of treatment units that should be utilized within the DPF 102, SCR 104 and/or DOC 120.
Software 142 and memory 144 may be present in the controller 130, which may be used for the various determinations, recommendations, outputs, alerts, controls, etc. discussed herein. The controller 130 can include the memory 144, display, input and other features and components. The controller 130 can include, for example, software 142, hardware, and combinations of hardware and software configured to execute several functions related to control of emissions and/or particulate as described herein. For example, the memory 144 can include stored data that reflects relationships between an orifice size the exhaust flow passes through and a combination of the NO2 to NOx ratio, the filtration efficiency, the soot loading and the pressure drop for various configurations of the DPF 102, SCR 104 and/or DOC 120. The controller 130 can include an analog, digital, or combination analog and digital controller including a number of components. As examples, the controller 130 can include integrated circuit boards or ICB(s), printed circuit boards PCB(s), processor(s), data storage devices, switches, relays, or any other components. Examples of processors can include any one or more of a microprocessor, a controller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or equivalent discrete or integrated logic circuitry.
The controller 130 can include or can be coupled to the memory 144 such as storage media to store and/or retrieve data or other information such as, for example, the relationships between the orifice size the exhaust flow passes through and a combination of the NO2 to NOx ratio, the filtration efficiency, the soot loading and the pressure drop. The controller 130 via memory 144 may also store other information. Storage devices, in some examples, are described as a computer-readable storage medium. The memory 144 can be used to store program instructions for execution by the controller 130, for example. The memory 144, for example, is used by software 142, applications, algorithms, as examples, running on and/or executed by the controller 130. The memory 144 can include short-term and/or long-term memory and can be volatile and/or non-volatile. Examples of non-volatile storage elements include magnetic hard discs, optical discs, floppy discs, flash memories, or forms of electrically programmable memories (EPROM) or electrically erasable and programmable (EEPROM) memories. Examples of volatile memories include random access memories (RAM), dynamic random access memories (DRAM), static random access memories (SRAM), and other forms of volatile memories known in the art.
The housing 106, plurality of tubes 200A, 200B, 200C and 200D and the interior wall 204 are configured to define the multi-flow split arrangement 113. The plurality of treatment units 202A, 202B, 202C and 202D can be positioned in the respective ones of the plurality of tubes 200A, 200B, 200C and 200D. As shown by arrows in
As shown in
In configuration (3), the DPF 102 has been varied from configuration (1) such that the at least one of the plurality of tubes 200A, 200B, 200C and 200D (tube 200D) does not contain one of the plurality of treatment units 202A, 202B and 202C as treatment unit 202D is absent. In configuration (3), the tube 200D includes a restriction device 210 configured to restrict the exhaust flow through the tube 200D. As shown in
In operation and use, a method 300 of operation of an aftertreatment system according to one example is shown in
Optionally the method 300 can include treating the exhaust flow of less than all of the multi-flow split arrangement includes removing or varying one or more of a plurality of treatment units from the apparatus based upon determining a NO2 to NOx ratio and a filtration efficiency and comparing the NO2 to NOx ratio and the filtration efficiency to governing regulatory standards. The method 300 can optionally include treating the exhaust flow of less than all of the multi-flow split arrangement includes leaving at least one of a plurality of tubes that define the multi-flow split arrangement empty or placing a restriction device within the at least one of the plurality of tubes to restrict the exhaust flow.
The method 300 can optionally include sensing NOx concentration and a diesel particulate concentration in the exhaust flow, determining a NO2 to NOx ratio and a filtration efficiency, and comparing the NO2 to NOx ratio and the filtration efficiency to governing regulatory standards. The method 300 can optionally include outputting a recommendation of at least a number of treatment units to install within the apparatus to treat the exhaust flow and/or outputting a recommendation to install a restriction device along one or more of the multi-flow split arrangement and a recommendation of an orifice size for the restriction device. The method 300 can optionally include determining based upon sensed data at least a pressure drop in the exhaust flow or a soot loading of the number of the treatment units and outputting at least the pressure drop or the soot loading along with the outputting of the recommendation of at least the number of treatment units to install or the recommendation to install the restriction device. The method 300 can optionally include adjusting a valve within at least one of the multi-flow split arrangement to restrict the exhaust flow therethrough.
The graph 400B shows pressure drop across the DPF as calculated and plotted with different orifice sizes used for the tube 200D (
The graph 400C plots the NO2 to NOx ratio as calculated and plotted with different orifice sizes used for the tube 200D (
The graph 400D plots the soot loading as calculated and plotted with different orifice sizes used for the tube 200D (
The data such as filtration efficiency of the DPF, pressure drop across the DPF or system, NO2 to NOx ratio of the system and/or the soot loading of the DPF can be varied by adding or removing the number of filtration units and/or a size or number of restriction devices utilized with the DPF or other apparatuses of the system. These various configurations for the DPF or other apparatuses allows the system to be varied to achieve a desired filtration efficiency of the DPF and NO2 to NOx ratio for the system to meet governing regulatory standards while accounting for changes in other system parameters such as pressure drop across the DPF or system, soot loading of the DPF and/or other system criteria.
The above detailed description is intended to be illustrative, and not restrictive. The scope of the disclosure should, therefore, be determined with references to the appended claims, along with the full scope of equivalents to which such claims are entitled.
