System and method for dynamically controlling filtration efficiency and fuel economy

Abstract

The present application relates to systems and methods for dynamically controlling filtration efficiency and fuel economy. An aftertreatment system includes an SCR system, a first filter, and a second filter disposed downstream of the first filter, and a bypass conduit providing a flow path that bypasses the second filter. A valve is operably coupled to the bypass conduit and is movable between a closed position in which exhaust gas flows through the second filter and an open position in which at least a portion of the exhaust gas flows through the bypass conduit. A controller is operably coupled to the valve, the controller configured to adjust the valve based on a first filtration efficiency of the first filter to cause the exhaust gas emitted from the aftertreatment device to the environment to have a particulate matter quantity that satisfies particulate matter emission standards.

Description

[0001] This application is a divisional application of the application filed on September 28, 2018, with application number 201880098216.2 and entitled "System and method for dynamically controlling filtration efficiency and fuel economy". Technical Field

[0002] This disclosure generally relates to aftertreatment systems for use with internal combustion (IC) engines. Background Technology

[0003] Exhaust aftertreatment systems are used to receive and treat exhaust gases produced by integrated combustion (IC) engines. Generally, an exhaust aftertreatment system includes any of several different components to reduce the level of harmful emissions present in the exhaust gases. For example, some exhaust aftertreatment systems for diesel-driven IC engines include a selective catalytic reduction (SCR) system, which includes a catalyst configured to remove NO in the presence of ammonia (NH3). x (NO and NO2 in a certain percentage) are converted into harmless nitrogen (N2) and water vapor (H2O). The aftertreatment system may also include filters, such as split-flow filters, configured to remove particulate matter (PM) from the exhaust gas, such as soot, dust, and inorganic particles. Increasingly stringent PM emission standards require filters to remove PM with high filtration efficiency. However, filters with high filtration efficiency impose high back pressure on the exhaust gas flowing through the aftertreatment system, which may reduce engine fuel economy. Summary of the Invention

[0004] The embodiments described herein generally relate to systems and methods for controlling the operation of an aftertreatment system based on the operating conditions of the engine that generates exhaust gases to achieve high filtration efficiency or high fuel economy. Specifically, the embodiments described herein relate to an aftertreatment system including a first filter; a second filter having a smaller pore size than the first filter, the second filter being positioned downstream of the first filter to provide high filtration efficiency; and a bypass duct for selectively bypassing the second filter when PM emission standards are met while high fuel economy is desired.

[0005] In some embodiments, an aftertreatment system configured to reduce components in exhaust gases produced by an engine includes a first filter and a second filter disposed downstream of the first filter. A bypass duct fluidly connects an exhaust gas flow path located downstream of the first filter and upstream of the second filter to an exhaust gas flow path located downstream of the second filter. A valve operatively coupled to the bypass duct is movable between a closed position and an open position, in which exhaust gases flow through the second filter and in the open position at least a portion of the exhaust gases flow through the bypass duct to bypass the second filter. A controller operatively coupled to the valve and configured to determine whether a first filtration efficiency of the first filter is greater than or less than or equal to a first filtration efficiency threshold. The controller is configured to control the valve such that when the first filtration efficiency is less than or equal to the first filtration efficiency threshold, the valve is closed to a greater extent than when the first filtration efficiency is greater than the first filtration efficiency threshold, such that when the first filtration efficiency is less than the first filtration efficiency threshold, a greater portion of the exhaust gases flow through the second filter, and the control of the valve results in the exhaust gases emitted from the aftertreatment system to the environment having a PM quantity below a predetermined threshold.

[0006] In some embodiments, the valve is initially in the closed position, in which substantially all of the exhaust gas flows through the second filter, and wherein, in response to the first filtration efficiency being equal to or greater than a first filtration efficiency threshold, the controller moves the valve to the open position, such that more of the exhaust gas flows through the bypass duct than through the second filter.

[0007] In some embodiments, for engine mileage of less than 5,000 miles, the first filtration efficiency threshold corresponds to a dust load of approximately 0.1 g / L to 10 g / L on the first filter.

[0008] In some embodiments, the controller is further configured to: determine a first pressure drop across the first filter; and determine the flow rate of the exhaust gas, wherein the controller is configured to determine the first filtration efficiency based on the first pressure drop and the flow rate of the exhaust gas.

[0009] In some embodiments, the controller is further configured to: determine a second pressure drop across the second filter; and, in response to the second pressure drop being greater than a predetermined pressure drop threshold, increase the opening of the valve to allow at least a portion of the exhaust gas to bypass the second filter.

[0010] In some embodiments, an aftertreatment system configured to reduce components in exhaust gases produced by an engine includes a first filter and a second filter disposed downstream of the first filter. A bypass duct fluidly connects an exhaust gas flow path located downstream of the first filter and upstream of the second filter to an exhaust gas flow path located downstream of the second filter. A valve is operatively connected to the bypass duct. The valve is movable between a closed position and an open position, in which exhaust gases flow through the second filter, and in an open position, at least a portion of the exhaust gases flow through the bypass duct to bypass the second filter. A controller is operatively connected to the valve. The controller is configured to determine whether the engine is operating under high particulate matter (PPM) conditions or low particulate matter (PPM) conditions. The controller is configured to control the valve such that during high PPM conditions, the valve is closed to a greater extent than during low PPM conditions, and a greater portion of the exhaust gases flow through the second filter during high PPM conditions compared to low PPM conditions, such that the control of the valve results in exhaust gases emitted from the aftertreatment system to the environment having a PM quantity below a predetermined threshold.

[0011] In some embodiments, the controller is configured to: in response to the engine operating under high particulate matter conditions, open the valve by a first predetermined amount such that the valve is closed to a greater extent than it is open, thereby allowing a larger portion of the exhaust gas to flow through the second filter than through the bypass duct; and in response to the engine operating under low particulate matter conditions, open the valve by a second predetermined amount such that the valve is open to a greater extent than it is closed, thereby allowing a larger portion of the exhaust gas to flow through the bypass duct than through the second filter.

[0012] In some embodiments, the second filter has a smaller pore size than the first filter, thereby achieving a higher filtration efficiency than the first filter.

[0013] In some embodiments, the post-treatment system further includes a selective catalytic reduction system positioned downstream of the first filter and upstream of the second filter.

[0014] In some embodiments, the high particulate matter operating conditions correspond to the presence of a larger amount of particulate matter in the exhaust gas produced by the engine, relative to the low particulate matter operating conditions.

[0015] In some embodiments, the second filter has a smaller diameter than the first filter, and the bypass pipe is located around the second filter.

[0016] In some embodiments, the valve is located at the inlet of the bypass duct, the valve comprising: a first ring defining a plurality of first openings; and a second ring defining a plurality of second openings, the second ring being adjacent to the first ring, wherein in the closed position, the plurality of first openings are misaligned with the plurality of second openings, allowing the exhaust gas to flow through the second filter, and wherein the second ring is configured to rotate relative to the first ring to move the valve to the open position, in which the plurality of first openings are aligned with the plurality of second openings, allowing at least a portion of the exhaust gas to flow through the plurality of first openings and the plurality of second openings into the bypass duct surrounding the second filter.

[0017] In some embodiments, the bypass conduit is defined to pass through the second filter, and the valve is disposed in the bypass conduit within the second filter.

[0018] In some embodiments, the controller is further configured to: determine the temperature of the exhaust gas; and, in response to the temperature of the exhaust gas being higher than a predetermined temperature threshold, close the valve to force hot exhaust gas to flow through the second filter for regenerating the second filter.

[0019] In some embodiments, the aftertreatment system further includes: an oxidation catalyst disposed upstream of the first filter; and a hydrocarbon introduction assembly configured to introduce hydrocarbons into the oxidation catalyst, wherein the controller is further configured to instruct the hydrocarbon introduction assembly to introduce hydrocarbons into the oxidation catalyst to raise the temperature of the exhaust gas above the predetermined temperature threshold.

[0020] In some embodiments, an aftertreatment system for reducing components in exhaust gases produced by an engine includes a first filter and a second filter located downstream of the first filter. A controller is operatively coupled to the first and second filters and configured to determine a first filtration efficiency of the first filter during operation of the aftertreatment system. In response to a first filtration efficiency equal to or greater than a first filtration efficiency threshold, the controller is configured to generate a fault code instructing a user to remove the second filter from the aftertreatment system.

[0021] In some embodiments, the post-processing system further includes a second filter pressure sensor operatively coupled to the second filter, and wherein the controller is further configured to: decode a pressure signal from the second filter pressure sensor to determine a pressure drop across the second filter; and generate the fault code in response to the pressure drop being greater than a predetermined pressure drop threshold.

[0022] In some embodiments, the aftertreatment system further includes a first filter pressure sensor operatively coupled to the first filter, and wherein the controller is further configured to: interpret a pressure signal from the first filter pressure sensor to determine a first pressure drop across the first filter; and determine the flow rate of the exhaust gas, wherein the first filtration efficiency is based on the first pressure drop and the flow rate.

[0023] In some embodiments, the valve includes a plurality of rings, including a first ring defining a plurality of first openings and a second ring defining a plurality of second openings. The second ring is adjacent to the first ring. The valve is movable between a closed position and an open position. In the closed position, the plurality of first openings are misaligned with the plurality of second openings to prevent fluid from flowing through the plurality of first openings and the plurality of second openings. In the open position, the second ring is rotated relative to the first ring such that the plurality of first openings are aligned with the plurality of second openings, allowing fluid to flow through.

[0024] In some embodiments, a filtration assembly for removing particulate matter from exhaust gas generated by an engine includes: a first filter; a second filter positioned downstream of the first filter; and the aforementioned valve, a first end of which is positioned at the outlet of the first filter and a second end of which is positioned at the inlet of the second filter, wherein in the closed position of the valve, substantially all of the exhaust gas flows through the second filter, and wherein in the open position of the valve, at least a portion of the exhaust gas flows through the valve and bypasses the second filter.

[0025] In some embodiments, the filtration assembly further includes a bypass conduit that fluidly connects an exhaust gas flow path located downstream of the first filter and upstream of the second filter to an exhaust gas flow path located downstream of the second filter, wherein at least a portion of the exhaust gas flows through the bypass conduit in the open position of the valve.

[0026] In some embodiments, the second filter has a smaller diameter than the first filter.

[0027] In some embodiments, the filtration assembly further includes a housing, wherein the first filter, the second filter, and the valve are all positioned within the housing such that the bypass conduit is defined between the outer surface of the second filter and the inner surface of the housing.

[0028] In some embodiments, an aftertreatment system configured to reduce components in exhaust gases produced by an engine includes a first filter and a second filter disposed downstream of the first filter. A bypass duct fluidly connects at least one of the following: fluidly connecting an exhaust gas flow path upstream of the first filter to an exhaust gas flow path between the first and second filters; or fluidly connecting an exhaust gas flow path between the first and second filters to an exhaust gas flow path downstream of the second filter. A valve is operably connected to the bypass duct, movable between a closed position, in which exhaust gases flow through the second filter, and in an open position, in which at least a portion of the exhaust gases flow through the bypass duct to bypass the second filter. A controller is operably connected to the valve. The controller is configured to determine whether the engine is operating under high PM operating conditions or low PM operating conditions. The controller is configured to control the valve such that during high PM operating conditions of the engine, the valve is closed to a greater extent than during low PM operating conditions of the engine, such that during high PM operating conditions of the engine, a greater portion of the exhaust gas flows through the second filter, and the control of the valve results in the exhaust gas emitted from the aftertreatment system to the environment having a PM level below a predetermined threshold.

[0029] In some embodiments, the first filter has a smaller pore size than the second filter, resulting in a higher filtration efficiency for the first filter than for the second filter.

[0030] It should be understood that all combinations of the foregoing concepts and the additional concepts discussed in more detail below (assuming that such concepts are not inconsistent with each other) are contemplated as part of the subject matter disclosed herein. In particular, all combinations of the claimed subject matter appearing in this disclosure are contemplated as part of the subject matter disclosed herein. Attached Figure Description

[0031] The foregoing and other features of this disclosure will become more fully apparent from the following description taken in conjunction with the accompanying drawings and the appended claims. It should be understood that these drawings depict only a few embodiments according to this disclosure and are therefore not intended to limit the scope of this disclosure, which will be described with further specific description and detail using the drawings.

[0032] Figure 1 This is a schematic diagram of a post-processing system according to an embodiment.

[0033] Figure 2 This is a schematic flowchart of an example method for controlling the filtering efficiency of a post-processing system according to an embodiment.

[0034] Figure 3A This is a schematic block diagram of a post-processing system according to another embodiment.

[0035] Figure 3B This is a schematic block diagram of a post-processing system according to another embodiment.

[0036] Figure 4 It can be included Figure 3A or Figure 3B A schematic block diagram of an embodiment of the control circuit in the post-processing system.

[0037] Figure 5 This is a graph showing the filter flow limit versus filtration efficiency for an example filter.

[0038] Figure 6 This is a schematic diagram of a post-processing system according to yet another embodiment.

[0039] Figure 7A This is a side perspective view of a portion of the post-processing system according to an embodiment, showing a first filter, a second filter, and a bypass duct; Figure 7B It is set in Figure 7A A side perspective view of the valve in the bypass piping of the after-treatment system.

[0040] Figure 8A yes Figure 7A A side view of a portion of the aftertreatment system, with the valve in the closed position, and Figure 8B The valve is shown in the open position.

[0041] Figure 9 This is a schematic diagram of a post-processing system according to yet another embodiment.

[0042] Figure 10 It is a graph showing the overall filtration efficiency of the post-treatment system, including the first filter and the second filter located downstream of the first filter.

[0043] Figures 11A-11B This is a schematic flowchart of a method for dynamically controlling the filtration efficiency of an aftertreatment system and controlling the fuel economy of an engine fluidly connected to the aftertreatment system, according to an embodiment.

[0044] Figure 12 According to the embodiments, it can be used as Figures 3A-3B , Figure 4 , Figure 6 or Figure 9 A schematic block diagram of the computing device for the controller shown.

[0045] Throughout the detailed description below, reference is made to the accompanying drawings. In the drawings, like reference numerals generally identify like parts unless the context otherwise requires. The illustrative embodiments described in the detailed description, drawings, and claims are not intended to be limiting. Other embodiments may be utilized, and other changes may be made without departing from the spirit or scope of the subject matter set forth herein. It will be readily understood that, as generally described herein and illustrated in the drawings, various aspects of this disclosure can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are expressly contemplated and constitute a part of this disclosure. Detailed Implementation

[0046] The embodiments described herein generally relate to systems and methods for controlling the operation of an aftertreatment system based on the operating conditions of the engine that generates exhaust gases to achieve high filtration efficiency or high fuel economy. Specifically, the embodiments described herein relate to an aftertreatment system including a first filter; a second filter having a pore size smaller than that of the first filter, the second filter being positioned downstream of the first filter to provide high filtration efficiency; and a bypass duct for selectively allowing the flow of exhaust gases to bypass the second filter when PM emission standards are met and high fuel economy is desired.

[0047] Increasingly stringent PM emission standards for exhaust gases from aftertreatment systems require filters within these systems to remove PM with high filtration efficiency. For example, China is implementing very strict regulations on PM emissions from aftertreatment systems. Conventional aftertreatment systems allow only short preconditioning times, posing a challenge to the performance of limited dust removal filters. Filters included in conventional aftertreatment systems may have openings that allow a significant amount of PM (e.g., soot or dust) to flow through during the preconditioning phase, for example, when the aftertreatment system is first run, or after filter regeneration, when there is no PM or the amount of retained PM in the filter is negligible. This results in a large amount of PM flowing through the filter during the preconditioning phase. While the accumulation of PM in the filter over time reduces its porosity and eventually improves its filtration efficiency to an ideal level, a high amount of PM passing through the filter during the preconditioning phase is undesirable. Filters with high filtration efficiency can address the PM problem. However, such filters impose high back pressure on the exhaust gases flowing through the aftertreatment system, which reduces engine fuel economy. Furthermore, conventional aftertreatment systems typically include a filter located upstream of the SCR system. This allows PM generated from the decomposition of the reducing agent to either enter the SCR system or be discharged unfiltered from the aftertreatment system, increasing the PM quantity. In some arrangements, the introduction of the reducing agent can increase the PM quantity downstream of the filter by 400%-600% due to its introduction and reaction with the exhaust gas in the SCR system.

[0048] Various embodiments of the systems and methods described herein offer benefits, including, for example, (1) providing high filtration efficiency during and after the pretreatment phase or during high PM operating conditions of the engine by placing a second smaller pore size filter downstream or upstream of a first larger pore size filter; (2) reducing PM levels during the introduction of a reducing agent into the exhaust gas by placing the second filter downstream of the SCR system of the aftertreatment system; (3) providing high filtration efficiency under high PM operating conditions and high fuel economy under low PM operating conditions while meeting emission standards by selectively bypassing at least a portion of the exhaust gas through the second filter; (4) allowing installation in existing aftertreatment systems with minimal modifications; and / or (5) reducing durability concerns by allowing the second filter to be selectively removed from the aftertreatment system.

[0049] Figure 1 This is a schematic diagram of an aftertreatment system 100 according to an embodiment. The aftertreatment system 100 is configured to receive exhaust gas from an engine (e.g., a diesel engine, gasoline engine, natural gas engine, dual-fuel engine, biodiesel engine, E-85 engine, or any other suitable engine) and reduce components in the exhaust gas, such as, for example, NO. x Gases, CO, hydrocarbons, etc. The aftertreatment system 100 may include a reducing agent storage tank 110, a reducing agent introduction assembly 120, a housing 101, a first filter 140, a second filter 142, and an SCR system 150.

[0050] The housing 101 defines an internal volume in which components of the post-treatment system 100 (i.e., the first filter 140, the second filter 142, and the SCR system 150) are positioned. The housing 101 may be formed of a rigid, heat-resistant, and corrosion-resistant material, such as stainless steel, iron, aluminum, metal, ceramic, or any other suitable material. The housing 101 may have any suitable cross-section, such as circular, square, rectangular, oval, elliptical, polygonal, or any other suitable shape.

[0051] Inlet conduit 102 is fluidly connected to the inlet of housing 101 and is configured to receive exhaust gas from the engine and convey it to the internal volume defined by housing 101. Furthermore, outlet conduit 104 may be connected to the outlet of housing 101 and is configured to discharge treated exhaust gas into the environment (e.g., treated by first filter 140 and / or second filter 142 to remove PM (e.g., soot and dust) and / or reduce components in the exhaust gas, such as NO included in the exhaust gas). x gas).

[0052] The first sensor 103 can be positioned in the inlet pipe 102. The first sensor 103 may include NO. x Sensor, the NO x The sensor is configured to measure NO in the exhaust gas included in the aftertreatment system 100. x The amount of gas, and may include physical NO. x Sensor or virtual NO x Sensors. In other embodiments, the first sensor 103 may include an exhaust gas flow rate sensor. In various embodiments, a temperature sensor, pressure sensor, oxygen sensor, or any other sensor may also be positioned in the inlet duct 102 to determine one or more operating parameters of the exhaust gas flowing through the housing 101 of the aftertreatment system 100.

[0053] The second sensor 105 can be positioned in the outlet pipe 104. The second sensor 105 may include a second NO. x Sensor, the second NO x The sensor is configured to determine the NO emitted into the environment after passing through the SCR system 150. x The amount of gas. In other embodiments, the second sensor 105 may include a PM sensor configured to determine the amount of PM (e.g., soot or dust included in the exhaust gas leaving filter 140). In still other embodiments, the second sensor 105 may include an ammonia sensor configured to measure the amount of ammonia in the exhaust gas exiting the SCR system 150, i.e., to determine an ammonia slip. This can be used as a measurement to determine the catalytic efficiency of the SCR system 150, to adjust the amount of reductant to be introduced into the SCR system 150, and / or to adjust the temperature of the SCR system 150 to allow the SCR system 150 to effectively use ammonia to catalytically decompose NO contained in the exhaust gas flowing through it. x Gas. In some embodiments, ammonia oxides (AMO) x The catalyst can be positioned downstream of the SCR system 150, for example in the outlet pipe 104, to decompose any unreacted ammonia in the exhaust gas downstream of the SCR system 150.

[0054] In some embodiments, the aftertreatment system 100 may further include (e.g., in housing 101) an oxidation catalyst 130 (e.g., a diesel engine oxidation catalyst) disposed upstream of the first filter 140. The oxidation catalyst 130 may be configured to oxidize unburned hydrocarbons and / or carbon monoxide included in the exhaust gas into CO2.

[0055] SCR system 150 includes an SCR catalyst formulated to decompose components in flowing exhaust gas. In some embodiments, SCR system 150 may include a selective catalytic reduction filter (SCRF) or any other aftertreatment component configured to decompose components (e.g., NO) in the exhaust gas flowing through housing 101 in the presence of a reducing agent. x Gases, such as nitrous oxide, nitrogen monoxide, nitrogen dioxide, etc., as described herein.

[0056] Any suitable SCR catalyst can be used, such as, for example, catalysts based on rhodium, cerium, iron, manganese, copper, vanadium, any other suitable catalyst, or combinations thereof. The SCR catalyst can be arranged on a suitable substrate (such as, for example, a ceramic (e.g., cordierite) or metal (e.g., kanthal) monolithic core) that can define a honeycomb structure. Coatings can also be used as support materials for the SCR catalyst. Such coating materials can include, for example, alumina, titanium dioxide, silica, any other suitable coating materials, or combinations thereof. Exhaust gas (e.g., diesel engine exhaust gas) can flow over and / or near the SCR catalyst, such that any NO contained in the exhaust gas... x The gas is further reduced to produce virtually no NO. x Waste gas.

[0057] In various embodiments, the post-treatment system 100 may also include other post-treatment components, such as an ammonia oxidation catalyst, a mixer, a baffle, or any other suitable post-treatment component.

[0058] A reducing agent port (not shown) may be located on a sidewall of housing 101 and configured to allow the reducing agent to be introduced through it into the internal volume defined by housing 101. The reducing agent port may be located upstream of SCR system 150 (e.g., allowing the reducing agent to be introduced into the exhaust gas upstream of SCR system 150) or above SCR system 150 (e.g., allowing the reducing agent to be introduced directly onto SCR system 150). In other embodiments where the reducing agent is introduced upstream of SCR system 150, a mixer, baffle, blade, or other structure may be located upstream of SCR system 150 to facilitate mixing of the reducing agent with the exhaust gas.

[0059] The reducing agent storage tank 110 is configured to store a reducing agent. The reducing agent is formulated to promote the absorption of components in the exhaust gas (e.g., NO contained in the exhaust gas). xThe decomposition of gases. Any suitable reducing agent can be used. In some embodiments, the exhaust gas includes diesel engine exhaust gas, and the reducing agent includes diesel engine exhaust gas treatment fluid. For example, diesel engine exhaust gas treatment fluid may include urea, an aqueous solution of urea, or any other fluid including ammonia, byproducts, or any other diesel engine exhaust gas treatment fluid as known in the art (e.g., with...). (The name refers to the diesel exhaust fluid sold). For example, the reducing agent may include an aqueous solution of urea having a specific ratio of urea to water. In a particular embodiment, the reducing agent may include an aqueous solution of urea comprising 32.5% by volume of urea and 67.5% by volume of deionized water, comprising 40% by volume of urea and 60% by volume of deionized water, or any other suitable ratio of urea to deionized water.

[0060] The reducing agent introduction assembly 120 is fluidly coupled to the reducing agent storage tank 110. The reducing agent introduction assembly 120 is configured to selectively introduce reducing agent into the SCR system 150, or upstream of it (e.g., into inlet pipe 102), or into a mixer (not shown) located upstream of the SCR system 150. The reducing agent introduction assembly 120 may include various configurations to facilitate receiving reducing agent from the reducing agent storage tank 110 and delivering reducing agent to the SCR system 150.

[0061] In various embodiments, the reducing agent introduction assembly 120 may also include one or more pumps (e.g., diaphragm pumps, positive displacement pumps, centrifugal pumps, vacuum pumps, etc.) for delivering the reducing agent to the SCR system 150 at operating pressures and / or flow rates. The reducing agent introduction assembly 120 may also include filters and / or screens (e.g., to prevent solid particles of reducing agent or contaminants from flowing into one or more pumps) and / or valves (e.g., check valves) for receiving reducing agent from the reducing agent storage tank 110.

[0062] Filters, check valves, pulsation dampers, or other structures may also be positioned downstream of one or more pumps in the reductant introduction assembly 120 and configured to remove contaminants and / or facilitate the delivery of reductant to the SCR system 150. In various embodiments, the reductant introduction assembly 120 may also include a bypass line configured to provide a return path for the reductant from one or more pumps to the reductant storage tank 110. A valve (e.g., an orifice valve) may be provided in the bypass line. In various embodiments, the reductant introduction assembly 120 may also include a mixing chamber configured to receive pressurized reductant from a metering valve at a controllable rate. The mixing chamber may also be configured to receive air (e.g., compressed air or a portion of exhaust gas) or any other inert gas (e.g., nitrogen), for example, from an air supply unit, to deliver a combined flow of air and reductant to the SCR system 150 through a reductant port.

[0063] The aftertreatment system 100 may further include a reducing agent injector fluidly coupled to the reducing agent introduction assembly 120 and configured to introduce a reducing agent (e.g., a combined flow of reducing agent and compressed air) into the SCR system 150. In various embodiments, the reducing agent injector may include a nozzle having a predetermined diameter. In various embodiments, the reducing agent injector may be positioned in a reducing agent port and configured to deliver a flow or jet of reducing agent into the internal volume of the housing 101 to facilitate the delivery of reducing agent to the SCR system 150.

[0064] In various embodiments, the reducing agent introduction assembly 120 may also include a dispensing valve, for example, positioned within the reducing agent delivery line, for dispensing reducing agent from the reducing agent introduction assembly 120 to the SCR system 150. The dispensing valve may include any suitable valve, such as a butterfly valve, gate valve, check valve (e.g., a tilting disc check valve, a swing check valve, a spool check valve, etc.), ball valve, spring-loaded valve, air-assisted injector, solenoid valve, or any other suitable valve. The dispensing valve may be selectively opened to introduce a predetermined quantity of reducing agent into the SCR system 150 or its upstream location during a predetermined time period.

[0065] The first filter 140 is configured to remove PM (e.g., soot, debris, inorganic particles, etc.) from exhaust gas. In various embodiments, the first filter 140 may include a ceramic filter. In a particular embodiment, the first filter 140 may include a split filter (e.g., a ceramic split filter). In other embodiments, the filter 140 may include a metal split filter. In still other embodiments, the first filter 140 may include a cordierite filter, which may be, for example, an asymmetric filter. In still other embodiments, the first filter 140 may be catalytically activated.

[0066] The second filter 142 is disposed downstream of the first filter 140. Although the second filter 142 is shown as disposed upstream of the SCR system 150, in other embodiments, the second filter 142 may be disposed downstream of the SCR system 150. The second filter 142 may include a ceramic filter, a diverter filter, a cordierite filter, or any other filter described with respect to the first filter 140. In some embodiments, the second filter 142 may include an uncoated filter.

[0067] In various embodiments, the first filter 140 may have a first pore size larger than the second pore size of the second filter 142, such that the second filter 142 has a higher filtration efficiency than the first filter 140. For example, certain emission standards (e.g., in Europe or China) may impose very high limits on PM emissions from aftertreatment systems. During the pretreatment phase (e.g., when the aftertreatment system 100 is new or after the first filter 140 has been regenerated), the first filter 140 may have a porosity that allows a greater amount of PM to pass through than permitted by the emission standards. Positioning the second filter 142 (with a smaller pore size and thus a higher filtration efficiency than the first filter 140) downstream of the first filter 140 allows for the filtration of a higher amount of PM from the exhaust gas (compared to the amount that the first filter 140 may filter). For example, the first filter 140 may have a first filtration efficiency of 70%, and the second filter 142 may have a second filtration efficiency of 90%, so that the post-treatment system 100 has a total filtration efficiency of 1-(1-70%)×(1-90%)=97%, which is higher than that of each of the individual filters 140 and 142, thereby effectively meeting the PM emission standards.

[0068] Over time, as exhaust gas continues to flow through the aftertreatment system 100, the first filter 140 may gradually become clogged with PM, resulting in a decrease in its porosity and an increase in its filtration efficiency. Over time, the first filtration efficiency of the first filter 140 reaches a first efficiency threshold at which the first filter 140 can meet PM emission standards. The first filtration efficiency can be based on the pressure drop across the first filter 140 (e.g., measured using a differential pressure sensor) and the exhaust gas flow rate, for example, the ratio of pressure drop to exhaust gas flow rate.

[0069] As the first filter 140 becomes increasingly clogged with particulate matter (PM), causing its filtration efficiency to increase, the second filter 142 also becomes increasingly clogged. This leads to an increase in exhaust back pressure, which reduces the engine's fuel economy. The second filter 142 can be removably coupled to the aftertreatment system 100 such that, in response to the first filtration efficiency of the first filter 140 reaching a first efficiency threshold, the second filter 142 can be removed from the aftertreatment system 100, for example, during a predetermined maintenance period, to reduce back pressure. In some embodiments, the second filter 142 can be removed if a second pressure drop across the second filter 142 is greater than a predetermined pressure drop threshold (which may correspond to high back pressure).

[0070] In some embodiments, the aftertreatment system 100 may further include a controller 170 communicatively coupled to the first filter 140 and / or the second filter 142. In various embodiments, the controller 170 may be included in control circuitry (e.g., control circuitry 371, which is further described in detail herein). The controller 170 is configured to determine a first filtration efficiency of the first filter 140 during operation of the aftertreatment system 100. For example, a first filter pressure sensor 138 (e.g., a differential pressure sensor) may be operatively coupled to the first filter 140 and configured to determine the pressure drop across the first filter 140. The controller 170 may be configured to interpret the pressure signal from the first filter pressure sensor 138 to determine the first pressure drop across the first filter 140. The controller 170 may also be configured to determine the exhaust gas flow rate (e.g., based on a signal received from an exhaust gas flow sensor or based on engine operating conditions). The controller 170 may determine the first filtration efficiency based on the first pressure drop and the exhaust gas flow rate (e.g., the ratio of the first pressure drop to the flow rate).

[0071] In response to a voltage drop exceeding a predetermined voltage drop threshold, controller 170 generates a fault code instructing the user to remove the second filter 142 from the aftertreatment system 100. The fault code may be stored in the memory of the vehicle's central controller or in the memory of any other component including the aftertreatment system 100, and may be retrieved during vehicle maintenance intervals. In other embodiments, controller 170 may also activate an indicator light (e.g., an indicator on a dashboard display) to notify the user that the second filter 142 should be removed.

[0072] In some embodiments, controller 170 may also be configured to determine the pressure drop across the second filter 142. For example, a second filter pressure sensor 148 may be operatively coupled to the second filter 142 and configured to determine the pressure drop across the second filter 142. Controller 170 may be configured to interpret the pressure signal from the second filter pressure sensor 148 to determine the pressure drop across the second filter 142. In response to a pressure drop greater than a predetermined pressure threshold (e.g., corresponding to a case where the second filter 142 is substantially clogged or a case where high back pressure is applied to the exhaust gas), controller 170 generates a fault code.

[0073] In a particular embodiment, the aftertreatment system 100 may further include a hydrocarbon (HC) introduction assembly 122, configured to introduce hydrocarbons into the exhaust gas flow path above or upstream of the oxidation catalyst 130. The introduced hydrocarbons are oxidized on the oxidation catalyst 130 and used to raise the temperature of the exhaust gas to a temperature sufficient to oxidize PM retained in the first filter 140 and / or the second filter 142, thereby regenerating the first filter 140 and / or the second filter 142.

[0074] For example, over time, filters 140 and / or 142 may become gradually clogged with PM. As described previously herein, this may improve the filtration efficiency of the first filter 140 and / or the second filter 142 due to the reduced porosity of filters 140 and 142, but it may also lead to an increase in exhaust back pressure, which reduces fuel efficiency. If not regenerated, filters 140 and 142 may eventually become completely clogged with PM, or the back pressure may become high enough to cause the first filter 140 and / or the second filter 142 to rupture. In some embodiments, in response to an increase in exhaust back pressure exceeding a predetermined pressure threshold, hydrocarbon introduction assembly 122 may be activated to introduce hydrocarbons into the exhaust gas, for example, into or upstream of oxidation catalyst 130, the predetermined pressure threshold corresponding to the amount of clogging of the first filter 140 and / or the second filter 142. For example, in response to a pressure drop across the second filter 142 exceeding the predetermined pressure threshold, controller 170 may activate hydrocarbon introduction assembly 122. Hydrocarbons can be burned in the exhaust gas, thereby raising the temperature of the exhaust gas above a temperature threshold sufficient to oxidize PM retained in the first filter 140 and / or the second filter 142, thus regenerating filters 140 and / or 142. For example, the second filter 142 can be regenerated before being removed from the aftertreatment system.

[0075] Figure 2 This is a schematic flowchart of method 200 according to an embodiment for controlling the filtration efficiency of an aftertreatment system (e.g., aftertreatment system 100) as a factor of fuel economy for an engine that generates exhaust gases flowing through the aftertreatment system. The aftertreatment system includes an SCR system (e.g., SCR system 150), a first filter (e.g., first filter 140) located upstream of the SCR system, and a second filter (e.g., second filter 142) located downstream of the first filter, for example, between the first filter and the SCR system or downstream of the SCR system. The second filter may have a smaller pore size than the first filter, as described earlier herein with respect to aftertreatment system 100.

[0076] Method 200 includes, at 202, determining the filtration efficiency of a first filter during operation of the aftertreatment system. For example, the filtration efficiency of the first filter 140 is determined by a controller 170. In some embodiments, method 200 may further include determining a first pressure drop across the first filter and the flow rate of the exhaust gas downstream of the first filter (e.g., via the controller 170). The filtration efficiency may be based on the first pressure drop and the flow rate of the exhaust gas, such as the ratio of pressure drop to flow rate.

[0077] At 204, it is determined whether the first filtration efficiency is equal to or greater than a first filtration efficiency threshold. In response to the first filtration efficiency of the first filter being equal to or greater than the first filtration efficiency threshold (204: Yes), method 200 includes, at 206, instructing the user to remove the second filter from the aftertreatment system. For example, as exhaust gas flows through the first filter 140, PM accumulates in the first filter 140, reducing its porosity and increasing its filtration efficiency. Once the first filtration efficiency of the first filter 140 reaches the first filtration efficiency threshold, which corresponds to the desired filtration efficiency from the first filter 140, the first filter 140 is sufficient to provide the desired filtration efficiency from the aftertreatment system 100, meeting PM emission standards without the second filter 142. The user may be instructed via an audio signal (e.g., an alarm), a video signal (e.g., illuminating an indicator light on a dashboard), or a fault code generated by the controller 170 (e.g., a second filter removal code, which may be provided to the user on demand).

[0078] In some embodiments, method 200 may further include, at 208, determining a second pressure drop across the second filter in response to a first filtration efficiency being less than a filtration efficiency threshold. If the pressure drop across the second filter at 210 is less than a predetermined pressure drop threshold, method 200 returns to operation 202. In some embodiments, in response to a second pressure drop being greater than the predetermined pressure drop threshold, at 212, at least regeneration of the second filter may be initiated. For example, the second filter 142 and optionally the first filter 140 may also be heated above the regeneration temperature (e.g., by a heater coupled to the second filter 142 and / or the first filter 140 or by an exhaust gas aftertreatment system 100 that maintains a temperature above the regeneration temperature) to oxidize PM (e.g., soot) accumulated in the second filter 142, and in some embodiments, also oxidizing PM (e.g., soot) accumulated in the first filter 140. The method then returns to operation 210. If it is determined that the second pressure drop is still greater than the predetermined pressure drop, at 214, the user is instructed to remove the second filter. For example, if the second pressure drop is higher than the predetermined pressure drop threshold, it may correspond to a high back pressure applied to the exhaust gas, which may reduce the fuel economy of the engine that generates the exhaust gas to below the desired level or damage the second filter 142.

[0079] In some embodiments, the second filter 142 may be rotatably mounted within the housing 101 and configured to rotate between a first configuration and a second configuration, in which the second filter 142 is positioned within an exhaust gas flow path, and in the second configuration, the second filter 142 rotates within the housing 101 to provide a flow path for exhaust gas to bypass the second filter 142. For example, a biasing member (e.g., a spring) may be coupled to the second filter 142 and configured to bias the second filter 142 toward the first configuration to allow exhaust gas to flow through the second filter 142. As the second filter 142 becomes gradually clogged, the pressure of the exhaust gas on the second filter 142 increases due to the decrease in porosity of the second filter 142. Once the pressure of the exhaust gas equals or exceeds a predetermined pressure threshold (which may occur after the first filter 140 has reached its filtration efficiency threshold), this pressure may be sufficient to overcome the biasing force of the biasing member to move the second filter 142 to the second configuration. This allows exhaust gas to bypass the second filter 142, thus reducing back pressure on the exhaust gas and improving fuel economy. This avoids the need to remove the second filter 142 from the housing 101.

[0080] In other embodiments, the post-processing system 100 may also include a bypass conduit (not shown), for example, referenced to Figure 3A The bypass conduit 345 described fluidly connects an exhaust gas flow path downstream of the first filter 140 and upstream of the second filter 142 to an exhaust gas flow path downstream of the second filter 142. A pressure-activated valve may be disposed in the bypass conduit and may be configured to open in response to the exhaust gas pressure exceeding a predetermined pressure threshold, for example, due to a decrease in the porosity of the second filter 142 as previously described herein. After regeneration of the second filter, the pressure-activated valve may close again, and the cycle may repeat.

[0081] Figure 3A This is a schematic diagram of an aftertreatment system 300 according to yet another embodiment. The aftertreatment system 300 is configured to receive exhaust gas from an engine (e.g., a diesel engine, gasoline engine, natural gas engine, dual-fuel engine, biodiesel engine, E-85 engine, or any other suitable engine) and reduce components in the exhaust gas, such as, for example, NO. x Gases, CO, hydrocarbons, etc. The aftertreatment system 300 may include a reducing agent storage tank 110, a reducing agent introduction assembly 120, a housing 301, a first filter 140, a second filter 142, and an SCR system 150, as described above with respect to the aftertreatment system 100.

[0082] Housing 301 defines an internal volume in which components of the aftertreatment system 300 (i.e., the first filter 140, the second filter 142, and the SCR system 150) are located, as described above herein. Inlet conduit 302 is fluidly connected to the inlet of housing 101 and is configured to receive exhaust gases from the engine and convey them to the internal volume defined by housing 301. Furthermore, outlet conduit 304 may be connected to the outlet of housing 301 and is configured to discharge treated exhaust gases into the environment (e.g., treated by the first filter 140 and the second filter 142 to remove PM (e.g., soot and dust) and / or reduce components in the exhaust gases, such as NO included in the exhaust gases). x (Gas). A first sensor 103 may be located in an inlet pipe 302, and a second sensor 105 may be located in an outlet pipe 304, as described earlier in this document with respect to the post-processing system 100.

[0083] In some embodiments, the aftertreatment system 300 may further include (e.g., in housing 301) an oxidation catalyst 130 (e.g., a diesel engine oxidation catalyst) disposed upstream of the first filter 140. The hydrocarbon introduction assembly 122 may be configured to introduce hydrocarbons (e.g., fuels such as diesel) into the exhaust gas upstream of or above the oxidation catalyst 130 to raise the temperature of the exhaust gas, for example, to regenerate the first filter 140 and / or the second filter 142.

[0084] The first filter 140 is located upstream of the SCR system 150, while the second filter 142 is located downstream of the first filter 140, for example, as... Figure 3A As shown, the second filter is located downstream of the SCR system 150. For example, introducing a reducing agent into the SCR system 150 can result in a large amount of solid particles (e.g., reducing agent particles, soot, dust, etc.) being present in the exhaust gas downstream of the SCR system 150, and positioning the second filter 142 downstream of the SCR system 150 allows for the capture of such particles downstream of the SCR system 150. In other embodiments, the second filter 142 may be located upstream of the SCR system 150. A pressure sensor 346 (e.g., a differential pressure sensor) is operatively coupled to the second filter 142 and configured to determine the pressure drop across the second filter 142. The pressure drop can indicate the degree of clogging of the second filter 142. The first filter 140 and the second filter 142 have the same structure and function as described with respect to the aftertreatment system 100.

[0085] The aftertreatment system 300 also includes a bypass duct 345 that fluidly connects an exhaust gas flow path downstream of the first filter 140 and upstream of the second filter 142 to an exhaust gas flow path downstream of the second filter 142. For example, the bypass duct 345 can fluidly connect the volume of housing 301 between the SCR system 150 and the second filter 142 to the volume of housing 301 downstream of the second filter 142. The bypass duct 345 thus provides a bypass flow path for the exhaust gas to bypass the second filter 142.

[0086] Valve 344 is operatively connected to bypass conduit 345. Valve 344 may include a butterfly valve, rotary valve, diaphragm valve, needle valve, pinch valve, check valve, or any other suitable valve. Valve 344 is movable between a closed position and an open position, in which exhaust gas flows through the second filter 142, and in the open position, at least a portion of the exhaust gas flows through bypass conduit 345 to bypass the second filter 142. In various embodiments, the degree of opening of valve 344 can be adjusted to control the amount of exhaust gas flowing through the second filter 142 and the amount of exhaust gas bypassing the second filter 142. For example, when the first filter 140 is new or recently regenerated, valve 344 may initially be closed to allow exhaust gas to flow through the second filter 142 and provide high filtration efficiency. Over time, the first filter 140 becomes gradually clogged with PM and experiences an increase in its initial filtration efficiency. Furthermore, the second filter 142 also becomes gradually clogged, as described earlier herein with respect to aftertreatment system 100, resulting in increased exhaust back pressure, which may reduce the fuel economy of the exhaust-generating engine. Therefore, valve 344 can be opened gradually to allow at least a portion of the exhaust gas to bypass the second filter 142 via bypass pipe 345, thereby reducing the back pressure on the exhaust gas. Once the first filtration efficiency of the first filter 140 has reached a first filtration efficiency threshold corresponding to the desired filtration efficiency from the aftertreatment system 300, and / or once the pressure drop across the second filter 142 is greater than the pressure drop threshold, valve 344 can be fully opened.

[0087] Although Figure 3A A bypass conduit and a second filter 142 with a smaller pore size, positioned downstream of a first filter 140 with a larger pore size, are shown. However, in other embodiments, the bypass conduit may be positioned across the upstream filter, or alternatively, attached to a bypass conduit positioned around the downstream filter. For example, Figure 3B This is a schematic block diagram of a post-processing system 300b according to another embodiment. Post-processing system 300b is similar to post-processing system 300, but has the following differences.

[0088] The aftertreatment system 300b includes a first filter 140b and a second filter 142b located downstream of the first filter 140b. A first bypass conduit 345b fluidly connects an exhaust gas flow path upstream of the first filter 140b to an exhaust gas flow path located between the first filter 140b and the second filter 142b. A first valve 344b is operatively connected to the first bypass conduit 345b. Furthermore, a second bypass conduit 365b fluidly connects the exhaust gas flow path between the first filter 140b and the second filter 142b to an exhaust gas flow path downstream of the second filter 142b. The first valve 344b and the second valve 364b can be selectively opened or closed to allow a larger portion of the exhaust gas to flow through the first filter 140b (with the first valve 344b closed and the second valve 364b open), a larger portion of the exhaust gas to flow through the second filter 142b (with the first valve 344b open and the second valve 364b closed), or the exhaust gas to flow through each of filters 140b and 142b (with both valves 344b and 364b closed).

[0089] In some embodiments, the first filter 140b may have a smaller pore size than the second filter 142b, and therefore a higher filtration efficiency. In such embodiments, the second bypass conduit 365b can be excluded, allowing control over the degree of opening of the first valve 344b to provide high fuel economy or high filtration efficiency, as described herein. Furthermore, the first filter 140b may have a smaller diameter than the second filter 142b. In other embodiments, the second filter 142b may have a higher filtration efficiency than the first filter 140b to provide high filtration efficiency or fuel economy, as previously referenced. Figure 3A As described.

[0090] Refer again Figure 3AThe controller 370 can be operatively coupled to the valve 344 and configured to move the valve 344 to an open position, a closed position, or control the degree of opening of the valve 344 to control the ratio of exhaust gas flowing through the second filter 142 or the bypass duct 345. In some embodiments, the controller 370 can also be communicatively coupled to the first sensor 103, the second sensor 105, and / or the pressure sensor 346. In some embodiments, the controller 370 can also be communicatively coupled to the engine and configured to determine one or more engine operating parameters associated with the engine (e.g., engine speed, engine torque, exhaust gas flow rate, fuel introduction rate, intake air flow rate, etc.). The controller 370 can be operatively coupled to these components using any type and any number of wired or wireless connections. For example, wired connections can include serial cables, fiber optic cables, CAT5 cables, or any other form of wired connection. Wireless connections can include the Internet, Wi-Fi, cellular, radio, Bluetooth, Zigbee, etc. In one embodiment, a controller local area network (CAN) bus provides the exchange of signals, information, and / or data. The CAN bus includes any number of wired and wireless connections.

[0091] In some embodiments, the controller 370 may be configured to determine the engine's operating conditions. For example, the controller 370 may be configured to receive an engine signal from the engine, a first sensor signal from the first sensor 103, and / or a second sensor signal from the second sensor 105 to determine the engine's operating conditions, such as whether the engine is operating under high PM operating conditions or low PM operating conditions. Under high PM operating conditions, the exhaust gas emitted by the engine contains a larger amount of PM (e.g., under high engine load conditions), while under low PM operating conditions, the amount of PM in the exhaust gas is lower than under high PM operating conditions (e.g., under steady-state or low load conditions).

[0092] Controller 370 is configured to control valve 344 such that during high particulate matter (PM) operating conditions of the engine, valve 344 is closed to a greater extent than during low particulate matter (PM) operating conditions, allowing a larger portion of the exhaust gas to flow through the second filter 142 during high particulate matter (PM) operating conditions. For example, in response to engine operation under high PM conditions, controller 370 can be configured to open valve 344 by a first predetermined amount, such that the degree of closure of valve 344 is greater than the degree of opening, thereby allowing a larger portion of the exhaust gas to flow through the second filter 142 compared to bypass duct 345 and providing high filtration efficiency. When the engine is operating under high PM conditions, controller 370 can completely close valve 344 or open valve 344 to a very small extent, allowing a larger portion of the exhaust gas to flow through the second filter 142 compared to bypass duct 345. As described above, the second filter 142 improves filtration efficiency. In some embodiments, high PM operating conditions correspond to a larger amount of reducing agent being introduced into the SCR system 150 compared to low PM operating conditions.

[0093] Conversely, in response to engine operation under low PM conditions, controller 370 can be configured to open valve 344 by a second predetermined amount, such that valve 344 is opened to a greater extent than it is closed, thereby causing a larger portion of the exhaust gas to flow through bypass duct 345 and providing higher fuel economy. For example, when the engine is operating under low PM conditions, controller 370 can be configured to open valve 344 to a greater extent or fully open valve 344, so that a larger portion or substantially all of the exhaust gas bypasses the second filter 142 via bypass duct 345. As described above, as the second filter 142 becomes gradually clogged, the back pressure on the exhaust gas increases, which reduces fuel economy. If the desired filtration efficiency of the aftertreatment system 300 is met (e.g., because the first filter 140 reaches a first filtration efficiency threshold), allowing a larger portion of the exhaust gas to bypass the second filter 142 reduces the back pressure on the exhaust gas and increases fuel economy. Valve 345 is controlled such that the exhaust gas emitted from the aftertreatment system 300 into the environment has a PM level below a predetermined threshold, for example, to meet emission standards. Therefore, regardless of whether the operating conditions are high PM or low PM, the controller 370 is configured to ensure that the exhaust gas emitted from the aftertreatment system 300 meets the desired emission standards.

[0094] In some embodiments, the controller 370 may be configured to determine the operating conditions of the aftertreatment system 300 (e.g., pressure drop across the first filter 140, filtration efficiency of the first filter 140, pressure drop across the second filter 142, flow rate and / or temperature of the exhaust gas) based on the operating conditions of the aftertreatment system 300, and to open or close the valve 344.

[0095] Controller 370 can be configured to determine whether a first filtration efficiency of the first filter 140 is less than or equal to a first filtration efficiency threshold or greater than the first filtration efficiency threshold. Controller 370 is configured to control valve 344 such that when the first filtration efficiency is less than or equal to the first filtration efficiency threshold, compared to when the first filtration efficiency is greater than the first filtration efficiency threshold, valve 344 is closed to a greater extent, allowing a larger portion of the exhaust gas to flow through the second filter 142 when the first filtration efficiency is less than the first filtration efficiency threshold. For example, when the first filtration efficiency is less than or equal to the first filtration efficiency threshold, valve 344 may initially be in a closed position, allowing substantially all of the exhaust gas to flow through the second filter 142. In response to the first filtration efficiency being greater than the first filtration efficiency threshold, controller 370 gradually opens valve 344 such that the valve is closed to a lesser extent than when the first filtration efficiency is less than or equal to the first filtration efficiency threshold, and allowing more exhaust gas to flow through the bypass duct 345 compared to the second filter 142.

[0096] Further elaborated, in some embodiments, controller 370 is configured to determine a first filtration efficiency of the first filter 140. If the first filtration efficiency is less than a first filtration efficiency threshold, controller 370 closes valve 344 to allow exhaust gas to flow through the second filter 142, thereby providing high filtration efficiency. In response to the first filtration efficiency being equal to or greater than the first filtration efficiency threshold, controller 370 may increase the opening of valve 344 (e.g., fully open valve 344) so ​​that at least a portion of the exhaust gas bypasses the second filter 142 via bypass duct 345. As described above, valve 345 is controlled such that the exhaust gas emitted from aftertreatment system 300 into the environment has a PM quantity below a predetermined threshold, for example, to meet emission standards.

[0097] In some embodiments, controller 370 may be configured to determine the pressure drop across the first filter 140. For example, a first pressure sensor 348 may be operatively coupled to the first filter 140 and configured to determine the pressure drop across the first filter 140. Controller 370 may be operatively coupled to the first pressure sensor 348 and configured to determine the first pressure drop thereon. Controller 370 may also be configured to determine the flow rate of the exhaust gas. Controller 370 may be configured to determine a first filtration efficiency of the first filter 140 based on the first pressure drop and the flow rate of the exhaust gas, such as the ratio between the pressure drop (e.g., differential pressure) and the flow rate.

[0098] For example, Figure 5A graph showing the filtration efficiency of a first filter according to a specific embodiment versus a flow limit across the first filter (i.e., the ratio of pressure drop across the first filter to the exhaust gas flow rate) is illustrated. As exhaust gas continues to flow through the first filter 140, the PM load (e.g., soot load or ash load) on the first filter 140 continues to increase, causing the filtration efficiency of the first filter (e.g., the first filter 140) to increase accordingly until the first filtration efficiency reaches a first filtration efficiency threshold (e.g., a filtration efficiency greater than 95%). In some embodiments, for exhaust-generating engine mileage of less than 5000 miles, the first filtration efficiency threshold corresponds to an ash load of 0.1 g / L to 10 g / L on the first filter 140. For example, as Figure 5 As shown, for a specific first filter, the first filtration efficiency threshold corresponds to a soot load of 0.25 g / L or an equivalent dust load of 2 g / L on the first filter, at which point the first filtration efficiency is close to 100%. It should be understood that in other embodiments, the first filtration efficiency threshold may vary depending on the specific first filter used in the post-treatment system 300.

[0099] In some embodiments, the controller 370 may also be configured to determine the pressure drop across the second filter 142. For example, the controller 370 may receive a pressure signal from the pressure sensor 346 and thereby determine the pressure drop across the second filter 142. In response to a pressure drop greater than a predetermined pressure drop threshold, the controller 370 may be configured to open the valve 344 to allow at least a portion of the exhaust gas to bypass the second filter 142 via the bypass duct 345. For example, a pressure drop across the second filter 142 greater than the predetermined pressure drop threshold may correspond to a high back pressure on the exhaust gas, which reduces fuel economy below a fuel economy threshold. Therefore, the controller 370 opens the valve 344 to allow at least a portion of the exhaust gas to bypass the second filter 142 and reduce the back pressure on the exhaust gas. In some embodiments, the controller 370 may be configured to open the valve 344 if the second filter 142 is difficult to regenerate or the temperature of the exhaust gas reaching the second filter 142 is below a predetermined temperature threshold (which may correspond to a pressure drop across the second filter 142 greater than the predetermined pressure drop threshold).

[0100] In some embodiments, the controller 370 may also be configured to determine the temperature of the exhaust gas near the inlet of the second filter 142. For example, the controller 370 may be communicatively coupled to a temperature sensor 341 located upstream of the second filter 142 and receive a temperature signal from the temperature sensor corresponding to the temperature of the exhaust gas at the inlet of the second filter 142. In response to the exhaust gas temperature exceeding a predetermined temperature threshold, the controller 370 may be configured to close valve 344 to force hot exhaust gas through the second filter 142 for regenerating the second filter 142. In some embodiments, the controller 370 may also be communicatively coupled to hydrocarbon introduction assembly 122 and configured to instruct the hydrocarbon introduction assembly 122 to introduce hydrocarbons into the oxidation catalyst 130 to raise the exhaust gas temperature above a predetermined temperature threshold, for example, for regenerating the first filter 140 and / or the second filter 142.

[0101] In certain embodiments, the controller 370 may be included in the control circuitry. For example, Figure 4 This is a schematic block diagram of a control circuit 371 including a controller 370 according to an embodiment. The controller 370 includes a processor 372, a memory 374 or any other computer-readable medium, and a communication interface 376. Furthermore, the controller 370 includes an engine operating condition determination circuit 374a, a pressure and flow rate determination circuit 374b, a temperature determination circuit 374c, and a valve control circuit 374d. It should be understood that the controller 370 is only one embodiment shown, and any other controller capable of performing the operations described herein may be used.

[0102] Processor 372 may include a microprocessor, a programmable logic controller (PLC) chip, an ASIC chip, or any other suitable processor. Processor 372 communicates with memory 374 and is configured to execute instructions, algorithms, commands, or other programs stored in memory 374.

[0103] Memory 374 includes any of the memory and / or storage components discussed herein. For example, memory 374 may include RAM and / or a cache for processor 372. Memory 374 may also include one or more storage devices (e.g., hard disk drives, flash drives, computer-readable media, etc.) that are local or remote relative to controller 370. Memory 374 is configured to store lookup tables, algorithms, or instructions.

[0104] In one configuration, the engine operating condition determination circuit 374a, pressure and flow rate determination circuit 374b, temperature determination circuit 374c, and valve control circuit 374d are implemented as machine- or computer-readable media (e.g., stored in memory 374) executable by a processor (e.g., processor 372). As described herein, and among other uses, the machine-readable media (e.g., memory 374) facilitates the performance of certain operations to achieve the reception and transmission of data. For example, the machine-readable media can provide instructions (e.g., commands, etc.) to, for example, acquire data. In this respect, the machine-readable media may include programmable logic defining the frequency of data acquisition (or data transmission). Therefore, the computer-readable media may include code, which can be written in any programming language, including but not limited to Java or similar languages ​​and any conventional procedural programming language, such as the "C" programming language or similar programming languages. The computer-readable program code can be executed on one processor or multiple remote processors. In the latter case, the remote processors can be connected to each other via any type of network (e.g., CAN bus, etc.).

[0105] In another configuration, the engine operating condition determination circuit 374a, pressure and flow rate determination circuit 374b, temperature determination circuit 374c, and valve control circuit 374d are implemented as hardware units, such as electronic control units. Therefore, the engine operating condition determination circuit 374a, pressure and flow rate determination circuit 374b, temperature determination circuit 374c, and valve control circuit 374d can be implemented as one or more circuit components, including but not limited to processing circuits, network interfaces, peripheral devices, input devices, output devices, sensors, etc.

[0106] In some embodiments, the engine operating condition determination circuit 374a, pressure and flow rate determination circuit 374b, temperature determination circuit 374c, and valve control circuit 374d may take the form of one or more analog circuits, electronic circuits (e.g., integrated circuits (ICs), discrete circuits, system-on-a-chip (SOC) circuits, microcontrollers, etc.), telecommunication circuits, hybrid circuits, and any other type of "circuit". In this regard, the engine operating condition determination circuit 374a, pressure and flow rate determination circuit 374b, temperature determination circuit 374c, and valve control circuit 374d may include any type of components for implementing or facilitating the implementation of the operations described herein. For example, circuits as described herein may include one or more transistors, logic gates (e.g., NAND, AND, NOR, OR, XOR, NOT, XNOR, etc.), resistors, multiplexers, registers, capacitors, inductors, diodes, wiring, etc.

[0107] Therefore, the engine operating condition determination circuit 374a, pressure and flow rate determination circuit 374b, temperature determination circuit 374c, and valve control circuit 374d may also include programmable hardware devices, such as field-programmable gate arrays, programmable array logic, programmable logic devices, etc. In this respect, the engine operating condition determination circuit 374a, pressure and flow rate determination circuit 374b, temperature determination circuit 374c, and valve control circuit 374d may include one or more memory devices for storing instructions executable by the processors of the engine operating condition determination circuit 374a, pressure and flow rate determination circuit 374b, temperature determination circuit 374c, and valve control circuit 374d. One or more memory devices and processors may have the same definitions as those provided below regarding memory 374 and processor 372.

[0108] In the illustrated example, controller 370 includes processor 372 and memory 374. Processor 372 and memory 374 may be constructed or configured to execute or implement the instructions, commands, and / or control processes described herein concerning engine operating condition determination circuit 374a, pressure and flow rate determination circuit 374b, temperature determination circuit 374c, and valve control circuit 374d. Therefore, the depicted configurations represent the foregoing arrangements in which engine operating condition determination circuit 374a, pressure and flow rate determination circuit 374b, temperature determination circuit 374c, and valve control circuit 374d are implemented as machine- or computer-readable media. However, as mentioned above, this description is not intended to be limiting, as other embodiments are contemplated, such as those mentioned above, in which at least one of the engine operating condition determining circuit 374a, pressure and flow rate determining circuit 374b, temperature determining circuit 374c, and valve control circuit 374d is configured as a hardware unit. All such combinations and variations are intended to fall within the scope of this disclosure.

[0109] Processor 372 may be implemented as one or more general-purpose processors, application-specific integrated circuits (ASICs), one or more field-programmable gate arrays (FPGAs), digital signal processors (DSPs), a set of processing units, or other suitable electronic processing units. In some embodiments, one or more processors may be shared by multiple circuits (e.g., engine operating condition determination circuit 374a, pressure and flow rate determination circuit 374b, temperature determination circuit 374c, and valve control circuit 374d), and may include the same processor or otherwise share the same processor. In some example embodiments, the processor may execute instructions stored or otherwise accessed via different areas of memory. Optionally or additionally, one or more processors may be configured to perform or otherwise perform certain operations independently of one or more coprocessors. In other example embodiments, two or more processors may be connected via a bus to enable independent, parallel, pipelined, or multithreaded instruction execution. All such variations are intended to fall within the scope of this disclosure. Memory 374 (e.g., RAM, ROM, flash memory, hard disk storage, etc.) may store data and / or computer code to facilitate the various processes described herein. Memory 374 may be communicatively connected to processor 372 to provide processor 372 with computer code or instructions for performing at least some of the processes described herein. Furthermore, memory 374 may be, or may include, tangible, non-transitory volatile or non-volatile memory. Therefore, memory 374 may include database components, object code components, scripting components, or any other type of information structure for supporting the various activities and information structures described herein.

[0110] Communication interface 376 may include a wireless interface (e.g., jack, antenna, transmitter, receiver, communication interface, wired terminal, etc.) for data communication with various systems, devices, or networks. For example, communication interface 376 may include an Ethernet card and port for sending and receiving data via an Ethernet-based communication network, and / or include a Wi-Fi communication interface for communicating with, for example, the first sensor 103, the second sensor 105, the engine, valve 344, pressure sensor 346, the first pressure sensor 348, the hydrocarbon introduction assembly 122, and / or any other component of the aftertreatment system 300. Communication interface 376 may be configured to communicate via a local area network or a wide area network (e.g., the Internet) and may use various communication protocols (e.g., IP, LON, Bluetooth, ZigBee, radio, cellular, near-field communication, etc.).

[0111] The engine operating condition determination circuit 374a can be configured to receive engine operating condition signals, for example, from the engine, the first sensor 103 and / or the second sensor 105, or any other sensor, and determine whether the engine is operating under high PM operating conditions or low PM operating conditions. Furthermore, the engine operating condition determination circuit 374a can also be configured to determine after-processing operating condition signals (e.g., from pressure sensors 346 and / or 348, temperature sensor 341, the first sensor 103, and / or the second sensor 105).

[0112] Valve control circuit 374d is configured to generate a valve signal, which is configured to open valve 344, close valve 344, or regulate the degree of opening of valve 344, as described above. In response to engine operation under high PM conditions, valve control circuit 374d can be configured to open valve 344 by a first predetermined amount, such that the degree of closure of valve 344 is greater than the degree of opening, or to completely close valve 344, to increase the filtration efficiency of aftertreatment system 300, as described above. Furthermore, in response to engine operation under low PM conditions, valve control circuit 374d can be configured to open valve 344 by a second predetermined amount, such that the degree of opening of valve 344 is greater than the degree of closure, or to completely open valve 344, to increase engine fuel economy, as described above.

[0113] Pressure and flow rate determination circuit 374b is configured to determine a first pressure drop across the first filter 140 (e.g., based on a pressure signal received from the first pressure sensor 348) and to determine the exhaust gas flow rate (e.g., based on a flow rate signal received from a flow rate sensor or based on one or more engine operating conditions). Pressure and flow rate determination circuit 374b can determine a first filtration efficiency of the first filter 140 based on the first pressure drop and the exhaust gas flow rate (e.g., the ratio of pressure drop to exhaust gas flow rate). In response to the first filtration efficiency being equal to or greater than a first filtration efficiency threshold, valve control circuit 374d can increase the opening of valve 344 or otherwise partially open valve 344.

[0114] In some embodiments, the pressure and flow rate determining circuit 374b may also be configured to determine the pressure drop across the second filter 142 (e.g., based on a pressure signal received from the pressure sensor 346). In response to a pressure drop across the second filter 142 exceeding a predetermined pressure drop threshold, the valve control circuit 374d may be configured to open the valve 344 to allow at least a portion of the exhaust gas to bypass the second filter 142, as described above herein.

[0115] Temperature determination circuit 374c can be configured to determine the temperature of the exhaust gas near the inlet of the second filter 142 (e.g., based on a temperature signal received from temperature sensor 341). In response to the exhaust gas temperature exceeding a predetermined temperature threshold, valve control circuit 374d can be configured to close valve 344 (e.g., close by a second predetermined amount or completely close valve 344) to force hot exhaust gas through the second filter 142 for regenerating the second filter 142, as described above. In some embodiments, temperature determination circuit 374c can also be configured to instruct hydrocarbon introduction assembly 122 to introduce hydrocarbons into oxidation catalyst 130 or the exhaust gas to raise the exhaust gas temperature to a predetermined temperature threshold for regenerating the first filter 140 and / or the second filter 142.

[0116] Figure 6 This is a schematic diagram of an aftertreatment system 400 according to another embodiment. The aftertreatment system 400 is configured to receive exhaust gas from an engine (e.g., a diesel engine, gasoline engine, natural gas engine, dual-fuel engine, biodiesel engine, E-85 engine, or any other suitable engine) and reduce components in the exhaust gas, such as, for example, NO. x For gases such as CO and hydrocarbons, the aftertreatment system 400 may include a reducing agent storage tank 110, a reducing agent introduction assembly 120, a housing 401, a first filter 140, a second filter 442 disposed downstream of the first filter 140, an SCR system 150 disposed downstream of the second filter 442, and a controller 370, as described above with respect to aftertreatment systems 100 and 300. In other embodiments, the second filter 442 may be disposed downstream of the SCR system 150. In some embodiments, the aftertreatment system 400 may also include an oxidation catalyst 130 disposed upstream of the first filter 140, and a hydrocarbon introduction assembly 122 for selectively introducing hydrocarbons into the exhaust gas, as described above.

[0117] The housing 401 includes an inlet conduit 402 and an outlet conduit 404, in which a first sensor 103 is disposed, and in which a second sensor 105 is disposed. The second filter 442 may have a smaller diameter than the first filter 140 or otherwise smaller than the diameter of the housing 401, such that a bypass conduit 445 is defined around the second filter 442 between the outer radial surface of the second filter 442 and the inner radial surface of the housing 401. The second filter 442 may have a smaller pore size than the first filter 140 and therefore a higher filtration efficiency, and may be functionally similar to the second filter 142 as described above. A pressure sensor 346 may be operatively coupled to the second filter 442 and configured to determine the pressure drop across the second filter 442. Furthermore, a temperature sensor 341 may be located upstream of the second filter 442 and configured to determine the temperature of the exhaust gas entering the second filter 442.

[0118] Valve 460 is disposed at the inlet of bypass duct 445 between the inner surface of housing 401 and the outer surface of the second filter 442. Valve 460 is configured to selectively open to control the amount of exhaust gas flowing through the second filter 442 and / or around the second filter 442 and through bypass duct 445. For example, controller 370 may be operatively coupled to valve 460 and configured to open valve 460, close valve 460, or open valve 460 by a predetermined amount, for example, to control the amount of exhaust gas flowing through the second filter 442 and through bypass duct 445, as described above.

[0119] In some embodiments, valve 460 may include an annular valve. Reference is also made to... Figures 7A-7B and Figures 8A-8B A portion of housing 401 is shown, housing 401 including a first filter 140, a second filter 442, and a valve 460 located between the first filter and the second filter. Figure 7BAs shown, valve 460 includes a plurality of rings, including a first ring 462 that defines a plurality of first openings 464, for example, through a plurality of equally spaced slits defined by the first ring 462. The first ring 462 defines a first diameter D1 at a first end 463 near the outlet of the first filter 140 and a second diameter D2 at a second end 465 near the inlet of the second filter 442, the second diameter D2 being smaller than the first diameter D1. The second diameter D2 may be approximately equal to the outer diameter of the second filter 442. The first end 463 may be coupled to the inner surface of housing 401 and / or the outer surface of the first filter 140, for example, to prevent exhaust gas from passing through and leaking between housing 401 and the first end 463. Furthermore, the second end 465 may be coupled to the inlet of the second filter 442, for example, to prevent exhaust gas from leaking between the second end 465 and the second filter 442. In various embodiments, the first ring 462 may be immovably disposed within housing 401.

[0120] Valve 460 also includes a second ring 466 defining a plurality of second openings 468, for example, through a plurality of equally spaced slits defined by the second ring 466. The second ring 466 abuts against and is axially aligned with the first ring 462. The second ring 466 may be substantially similar in size and shape to the first ring 462. Furthermore, the radial spacing between the plurality of first openings 464 and the plurality of second openings 468 may be approximately equal to each other.

[0121] The second ring 466 can rotate relative to the first ring 462, for example, by a scissor motion, so that in the closed position of valve 460 ( Figure 8A Multiple first openings 464 and multiple second openings 468 are misaligned, causing exhaust gas to flow through the second filter 442. Figure 8B In the open position shown, the second ring 466 rotates relative to the first ring 462 to move the valve 460 to the open position, where the plurality of first openings 464 align with the plurality of second openings 468, thereby defining a flow path therethrough. When the valve 460 is in the closed position, more exhaust gas flows through the second filter 442 compared to when the valve 460 is in the open position. In some embodiments, in the open position of the valve 460, at least a portion of the exhaust gas flows through the plurality of first openings 464 and the plurality of second openings 468 and flows around the second filter 442 through the bypass conduit 445, thereby bypassing the second filter 442. In various embodiments, an external rotary actuator with a cam can be used to provide six degrees of rotation to the second ring 466 relative to the first ring 462 to open or close the valve 460. The second ring 466 can be variably rotated relative to the first ring 462 to control the amount of exhaust gas flowing through the second filter 442 and the bypass conduit 445.

[0122] Although shown as including a first ring 462 and a second ring 466, in other embodiments, valve 460 may include more than two rings, such as three or four rings, each with a predetermined interval between them. For a two-ring arrangement, valve 460 may have a 50% open front region. In a three-ring arrangement, two of the rings may be rotatable relative to a third fixed ring, and the valve may provide an open front region of up to 66%. Similarly, in a four-ring arrangement, at least two of the rings may be rotatable, enabling the valve to provide an open front region of up to 75%.

[0123] Figure 9 This is a schematic diagram of an aftertreatment system 500 according to an embodiment. The aftertreatment system 500 is configured to receive exhaust gas from an engine (e.g., a diesel engine, gasoline engine, natural gas engine, dual-fuel engine, biodiesel engine, E-85 engine, or any other suitable engine) and reduce components in the exhaust gas, such as, for example, NO. x Gases, CO, hydrocarbons, etc. The aftertreatment system 500 may include a housing 501, a first filter 140, an SCR system 150 disposed downstream of the first filter 140, a second filter 542 disposed downstream of the SCR system 150, and a controller 370, as described above. In other embodiments, the second filter 442 may be disposed upstream of the SCR system 150 and downstream of the first filter 140. In some embodiments, the aftertreatment system 500 may further include an oxidation catalyst 130 disposed upstream of the first filter 140. Furthermore, an ammonia leak catalyst may be disposed downstream of the SCR system 150.

[0124] The housing 501 includes an inlet conduit 502 and an outlet conduit 504, with a first sensor 103 disposed in the inlet conduit and a second sensor 105 disposed in the outlet conduit. A reducing agent injector 582 may be disposed upstream of the SCR system 150 and configured to introduce reducing agent into the exhaust gas. In some embodiments, the aftertreatment system 500 may further include a mixer 580 disposed upstream of the SCR system 150 and configured to facilitate mixing of the reducing agent with the exhaust gas. A plurality of temperature sensors T1, T2, T3, T4, and T5 may be disposed at different locations along the housing 501 and configured to measure the temperature of the exhaust gas at the respective locations. As described above, a first pressure sensor 348 is operatively coupled to a first filter 140 and configured to determine the pressure drop across the first filter 140.

[0125] The second filter 542 is disposed downstream of the SCR system 150. The second filter 542 may have a smaller pore size than the first filter 140, and therefore a higher filtration efficiency, and may be functionally similar to the second filters 142, 442. The second filter 542 defines a bypass conduit 545 passing through it, for example, through its longitudinal axis. A valve 544 (e.g., a butterfly valve) is disposed in the bypass conduit 545 and is movable between an open position and a closed position. For example, the controller 370 may be configured to instruct the valve 544 to move to the closed position in response to high PM operating conditions of the engine when a first filtration efficiency of the first filter 140 is lower than a first filtration efficiency threshold and / or if the pressure drop across the second filter 542 is lower than a predetermined pressure drop threshold. As described earlier in this document, in response to low PM engine operating conditions, or when the first filtration efficiency of the first filter 140 reaches a first filtration efficiency threshold, the controller 370 may be configured to open the valve 544, allowing at least a portion of the exhaust gas to flow through the bypass duct 545 (which is limited to passing through the second filter 542), thereby reducing the back pressure on the exhaust gas and increasing fuel economy.

[0126] Figure 10 This is a graph showing the total filtration efficiency versus time for an aftertreatment system connected to an engine operating under high engine load. The aftertreatment system includes a first filter with a first filtration efficiency and a second filter with a second filtration efficiency greater than the first filtration efficiency. The second filter is located downstream of the first filter. For example, the first filter may be a new filter or a recently regenerated filter, and the first filtration efficiency may be below a first filtration efficiency threshold, which is insufficient to provide sufficient filtration efficiency to meet the particulate emission standards desired by the aftertreatment system.

[0127] The aftertreatment system also includes bypass ducts (e.g., bypass ducts 345, 445, 545) having valves disposed thereon (e.g., valves 344, 460, 544) and configured to allow at least a portion of the exhaust gas to bypass the second filter when the valves are open. Figure 10As shown, when the valve is open, allowing the exhaust gas or a large portion of it to bypass the second filter, the overall filtration efficiency of the aftertreatment system is approximately 50% of the efficiency of the first filter, which may be lower than the desired filtration efficiency of the aftertreatment system. Conversely, when the valve is closed, most or almost all of the exhaust gas is forced through the second filter. In this configuration, the overall filtration efficiency of the aftertreatment system is approximately 100%, corresponding to the filtration efficiency of each of the first and second filters, as described earlier in this document. This demonstrates that including a second filter in the aftertreatment system can selectively increase the filtration efficiency of the aftertreatment system by closing the valve, and can selectively increase engine fuel economy by opening the valve to reduce back pressure on the exhaust gas, as described earlier in this document.

[0128] Figures 11A-11B This is a schematic flow diagram of a method 600 for controlling the filtration efficiency and fuel economy of an aftertreatment system according to one embodiment. The aftertreatment system (e.g., aftertreatment systems 300, 400, 500) may include a first filter (e.g., a first filter); a second filter (e.g., second filters 142, 442, 542) located downstream of the first filter; a bypass duct (e.g., bypass duct 345, 445, 545) fluidly connecting an exhaust gas flow path located downstream of the first filter and upstream of the second filter to an exhaust gas flow path located downstream of the second filter; and valves (e.g., valves 344, 460, 544) operatively connected to the bypass duct. In various embodiments, the aftertreatment system may also include an SCR system (e.g., SCR system 150) located upstream or downstream of the second filter.

[0129] Method 600 includes, at 602, determining the engine's operating conditions. For example, controller 370 may be configured to receive signals from the engine, first sensor 103, second sensor 105, pressure sensor 346, or first pressure sensor 348 to determine the engine's operating conditions. At 604, determining whether the engine is operating under high PM conditions. In response to the engine operating under high PM conditions (604: yes) (or additionally, if high filtration efficiency is desired), at 606, a valve is opened by a first predetermined amount such that the valve is closed to a greater extent than it is open, thereby allowing a larger portion of the exhaust gas to flow through the second filter compared to the bypass duct, and providing high filtration efficiency. For example, controller 370 may be configured to slightly open or substantially close valves 344, 460, 544 to allow a larger portion (e.g., substantially all of the exhaust gas) to flow through the second filter, thus providing high filtration efficiency.

[0130] In response to the engine operating under low PM conditions (604: No) (or alternatively, if high fuel economy is desired), at 608, the valve opens a second predetermined amount, such that the valve is open to a greater extent than it is closed, thereby allowing a larger portion of the exhaust gas to flow through the bypass duct and providing high fuel economy. For example, controller 370 may open valves 344, 460, 544 to a large extent, such as fully open, to allow a larger portion (e.g., substantially all of the exhaust gas) to bypass the second filter (e.g., second filters 142, 442, 542) via the bypass duct (e.g., bypass ducts 345, 445, 545), thus reducing back pressure on the exhaust gas and providing high fuel economy.

[0131] In some embodiments, method 600 further includes, at 610, determining a first filtration efficiency of the first filter. For example, controller 370 may determine a first pressure drop across the first filter 140, determine the flow rate of the exhaust gas, and determine the first filtration efficiency of the first filter 140 based on the pressure drop across the first filter and the exhaust gas flow rate, as described above herein.

[0132] At 612, it is determined whether the first filtration efficiency exceeds, for example, a predetermined filtration efficiency threshold determined by controller 370. If the first filtration efficiency is less than the predetermined filtration efficiency threshold (612: No), for example, corresponding to the desired filtration efficiency of the aftertreatment system, method 600 returns to operation 610. In response to the first filtration efficiency exceeding the predetermined filtration efficiency threshold, at 614, the valve opens by a predetermined amount, for example, fully open, to allow at least some or substantially all of the exhaust gas to bypass the second filter via a bypass duct. This reduces the back pressure of the exhaust gas and improves fuel economy, while providing the desired filtration efficiency via the first filter.

[0133] In some embodiments, method 600 further includes, at 616, determining the pressure drop across the second filter. For example, controller 370 may interpret a signal from pressure sensor 346 to determine the pressure drop across the second filter. At 618, determining whether the pressure drop exceeds a pressure drop threshold. The pressure drop may be correlated with the amount of blockage corresponding to the amount of back pressure applied to the exhaust gas. If the pressure drop is less than the pressure drop threshold (618: No), the method returns to operation 616. In response to the pressure drop being greater than a predetermined threshold (e.g., corresponding to excessively high exhaust gas back pressure), a valve opens (e.g., via controller 370) to allow at least a portion of the exhaust gas to bypass the second filter via a bypass duct, thereby reducing the back pressure on the exhaust gas.

[0134] In some embodiments, method 600 further includes, at 622, determining the temperature of the exhaust gas near the inlet of the second filter. For example, controller 370 may be configured to receive a temperature signal from temperature sensor 341 and interpret the temperature signal to determine the temperature of the exhaust gas at the inlet of the second filter. At 624, determining whether the temperature exceeds a predetermined temperature threshold. If the temperature is below the predetermined temperature threshold, method 600 returns to operation 622. In response to the exhaust gas temperature being higher or greater than the predetermined temperature threshold, a valve closes to force hot exhaust gas through the second filter for filter regeneration. For example, controller 370 may be configured to close valves 344, 460, 544 to force exhaust gas through second filters 142, 442, 542, thereby regenerating the second filters. In some embodiments, where the aftertreatment system includes a hydrocarbon introduction assembly (e.g., hydrocarbon introduction assembly 122), the method may further include introducing hydrocarbons into an oxidation catalyst (e.g., oxidation catalyst 130) to raise the temperature of the exhaust gas above the predetermined temperature threshold.

[0135] In some embodiments, controller 370, control circuit 371, or any of the controllers or control circuits described herein may include a system computer of an apparatus or system comprising after-processing systems 300, 400, 500 (e.g., a vehicle, engine, or generator set). For example, Figure 12 This is a block diagram of a computing device 730 according to an illustrative embodiment. The computing device 730 can be used to perform any of the methods or processes described herein, such as method 200 or 600. In some embodiments, a controller 370 may include the computing device 730. The computing device 730 includes a bus 732 or other communication components for transmitting information. The computing device 730 may also include one or more processors 734 or processing circuitry coupled to the bus 732 for processing information.

[0136] The computing device 730 also includes a main memory 736, such as random access memory (RAM) or other dynamic storage device, coupled to the bus 732, for storing information and instructions to be executed by the processor 734. The main memory 736 can also be used to store location information, temporary variables, or other intermediate information during instruction execution by the processor 734. The computing device 730 may also include a ROM 738 or other static storage device coupled to the bus 732 for storing static information and instructions for the processor 734. A storage device 740 (such as a solid-state device, disk, or optical disk) is coupled to the bus 732 for persistently storing information and instructions. For example, instructions corresponding to the operations of methods 200 and 600 may be stored on the storage device 740. The computing device 730 may be coupled via the bus 732 to a display 744, such as a liquid crystal display or an active matrix display, for displaying information to a user. An input device 742 (such as a keyboard or alphanumeric keypad) may be coupled to the bus 732 for transmitting information and command selections to the processor 734.

[0137] According to various embodiments, the methods described herein can be implemented by computing device 730, i.e., computing device 730 executes an instruction arrangement (e.g., the operation of method 200) contained in main memory 736 in response to processor 734. Such instructions may be read into main memory 736 from another non-transitory computer-readable medium (such as storage device 740). Execution of the instruction arrangement contained in main memory 736 causes computing device 730 to perform the illustrative process described herein. In a multiprocessing arrangement, one or more processors may also be used to execute the instructions contained in main memory 736. In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software instructions to implement the illustrative embodiments. Therefore, the embodiments are not limited to any particular combination of hardware and software.

[0138] Although Figure 12 An example computing device is described herein, but the embodiments described herein may be implemented in other types of digital electronic devices or in computer software, firmware or hardware (including the structures disclosed herein and their structural equivalents) or in one or more combinations thereof.

[0139] The embodiments described in this specification can be implemented in digital electronic devices or in computer software, firmware, or hardware (including the structures disclosed in this specification and their structural equivalents) or in one or more combinations thereof. The embodiments described in this specification can be implemented as one or more computer programs (i.e., one or more circuits of computer program instructions) encoded on one or more computer storage media for execution by a data processing device or for controlling the operation of a data processing device. The computer storage media includes non-transitory computer-readable media and can be a computer-readable storage device, a computer-readable storage substrate, a random or serial access memory array or device, or a combination thereof, or can be included in a computer-readable storage device, a computer-readable storage substrate, a random or serial access memory array or device, or a combination thereof. Furthermore, although the computer storage medium is not a propagating signal, it can be a source or destination of computer program instructions encoded in an artificially generated propagating signal. The computer storage medium can also be one or more separate components or media (e.g., multiple disks or other storage devices) or contained within such one or more separate components or media. Accordingly, the computer storage medium is both tangible and non-transitory.

[0140] The operations described herein can be performed on data stored on one or more computer-readable storage devices or received from other sources by a data processing apparatus. The terms "data processing apparatus" or "computing device" encompass all types of means, devices, and machines for processing data, including, for example, programmable processors, computers, systems-on-a-chip, or combinations thereof. The apparatus may include special-purpose logic, such as FPGAs (Field-Programmable Gate Arrays) or ASICs (Application-Specific Integrated Circuits). In addition to hardware, the apparatus may also include code that creates an execution environment for the computer program in discussion, such as code constituting processor firmware, protocol stacks, database management systems, operating systems, cross-platform runtime environments, virtual machines, or combinations thereof. The apparatus and execution environment can implement a variety of different computing model infrastructures, such as network services, distributed computing, and grid computing infrastructures.

[0141] Computer programs (also known as programs, software, software applications, scripts, or code) can be written in any programming language (including compiled or interpreted languages, declarative or procedural languages) and can be deployed in any form (including as standalone programs or as circuits, components, subroutines, objects, or other units suitable for use in a computing environment). A computer program may, but does not need to, correspond to a file in a file system. A program may be stored as part of a file containing other programs or data (e.g., stored in one or more scripts within a markup language document), a single file dedicated to the program under discussion, or one or more co-located files (e.g., a file storing portions of one or more circuits, subroutines, or code). A computer program can be deployed to execute on a single computer, on multiple computers located in one location, or distributed across multiple locations and interconnected by a communication network.

[0142] Processors suitable for executing computer programs include, for example, both general-purpose microprocessors and special-purpose microprocessors, and any one or more processors in any type of digital computer. Typically, a processor receives instructions and data from read-only memory or random access memory, or both. The basic components of a computer are a processor for performing actions according to instructions and one or more memory devices for storing instructions and data. Typically, a computer will also include one or more mass storage devices (e.g., hard disks, or flash drives) for storing data, or operatively coupled to receive data from or transfer data to such one or more mass storage devices, or both. However, a computer does not need to have such devices. Devices suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices, including, for example, semiconductor memory devices (e.g., EPROM, EEPROM, and flash memory devices); or hard disks (e.g., internal hard disks or removable disks). Processors and memory may be implemented by or incorporated into special-purpose logic.

[0143] It should be noted that the term "example" used herein to describe various embodiments is intended to indicate possible examples, representations, and / or illustrations of possible embodiments (and such term is not intended to imply that such embodiments must be particular or best examples).

[0144] As used herein, the term "basic" and similar terms are intended to have a broad meaning consistent with common and accepted use by one of ordinary skill in the art to which the subject matter of this disclosure pertains. Those skilled in the art who consult this disclosure will understand that these terms are intended to allow for the description of certain features described and claimed, without limiting the scope of those features to the precise arrangements and / or numerical ranges provided. Therefore, these terms should be interpreted as indicating that non-substantial or insignificant modifications or alterations to the described and claimed subject matter are considered to be within the scope of the invention as set forth in the appended claims.

[0145] As used herein, the term “about” generally means the value plus or minus 10%. For example, about 0.5 would include 0.45 and 0.55, about 10 would include 9 to 11, and about 1000 would include 900 to 1100.

[0146] As used herein, the term "joint" and similar terms mean two components joined together, directly or indirectly. Such a joint can be fixed (e.g., permanent) or movable (e.g., removable or releasable). Such a joint can be achieved by integrating two components, or two components and any additional intermediate components, into a single unit or by attaching two components, or two components and any additional intermediate components, to each other.

[0147] It is important to note that the structures and arrangements of the various exemplary embodiments are merely illustrative. While only a few embodiments are described in detail in this disclosure, those skilled in the art will readily recognize that many modifications (e.g., variations in the size, dimensions, structure, shape and proportion of various elements, values ​​of parameters, installation arrangements, use of materials, color, orientation, etc.) are possible without substantially departing from the novel teachings and advantages of the subject matter described herein. Furthermore, it should be understood that features from one embodiment disclosed herein may be combined with features from other embodiments disclosed herein, as will be understood by those skilled in the art. Other substitutions, modifications, variations, and omissions may also be made in the design, operating conditions, and arrangements of the various exemplary embodiments without departing from the scope of these embodiments.

[0148] While this specification contains many specific implementation details, these should not be construed as limiting the scope of any embodiment or potentially claimed content, but rather as descriptions of features specific to particular implementations of particular embodiments. Certain features described in the context of individual embodiments in this specification may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments. Furthermore, while features may be described above as functioning in certain combinations and even initially claimed in this way, one or more features from a claimed combination may be removed from that combination in some cases, and the claimed combination may involve sub-combinations or variations thereof.

Claims

1. An aftertreatment system configured to reduce components in exhaust gases produced by an engine, the aftertreatment system comprising: First filter; A second filter is disposed downstream of the first filter; A bypass duct that fluidly connects the exhaust gas flow path located downstream of the first filter and upstream of the second filter to the exhaust gas flow path located downstream of the second filter. A valve operably connected to the bypass conduit, the valve being movable between a closed position and an open position, in which the exhaust gas flows through the second filter, and in the open position, at least a portion of the exhaust gas flows through the bypass conduit to bypass the second filter; as well as A controller, operably coupled to the valve, is configured to: Determine whether the engine is operating under high particulate matter conditions or low particulate matter conditions; The valve is controlled such that during high particulate matter operating conditions of the engine, the valve is closed to a greater extent than during low particulate matter operating conditions of the engine, such that a greater portion of the exhaust gas flows through the second filter during high particulate matter operating conditions than during low particulate matter operating conditions of the engine, and the control of the valve results in the exhaust gas emitted from the aftertreatment system having a particulate matter content below a predetermined threshold. The valve is located at the inlet of the bypass pipe, and the valve includes: The first ring, which defines multiple first openings; and The second ring defines a plurality of second openings, and the second ring is adjacent to the first ring. In the closed position, the plurality of first openings are misaligned with the plurality of second openings, allowing the exhaust gas to flow through the second filter, and wherein the second ring is configured to rotate relative to the first ring to move the valve to the open position, in which the plurality of first openings are aligned with the plurality of second openings, allowing at least a portion of the exhaust gas to flow through the plurality of first openings and the plurality of second openings into the bypass duct located around the second filter.

2. The post-processing system according to claim 1, wherein, The controller is configured to: In response to the engine operating under the high particulate matter conditions, the valve is opened by a first predetermined amount, such that the degree of closure of the valve is greater than the degree of opening, thereby allowing a larger portion of the exhaust gas to flow through the second filter compared to the flow through the bypass duct; as well as In response to the engine operating under the low particulate matter conditions, the valve is opened by a second predetermined amount, such that the valve is opened to a greater extent than it is closed, thereby allowing a larger portion of the exhaust gas to flow through the bypass duct than through the second filter.

3. The post-processing system according to claim 1, wherein, The second filter has a smaller pore size than the first filter, which makes the second filter have a higher filtration efficiency than the first filter.

4. The post-treatment system according to claim 1 further includes a selective catalytic reduction system positioned downstream of the first filter and upstream of the second filter.

5. The post-processing system according to claim 1, wherein, Compared to the low particulate matter operating conditions, the high particulate matter operating conditions correspond to the presence of a larger amount of particulate matter in the exhaust gas generated by the engine.

6. The post-processing system according to any one of claims 1-5, wherein, The second filter has a smaller diameter than the first filter, and the bypass pipe is located around the second filter.

7. The post-processing system according to any one of claims 1-5, wherein, The bypass conduit is defined to pass through the second filter, and the valve is disposed in the bypass conduit within the second filter.

8. The post-processing system according to any one of claims 1-5, wherein, The controller is also configured to: Determine the temperature of the exhaust gas; and In response to the exhaust gas temperature being higher than a predetermined temperature threshold, the valve is closed to force the hot exhaust gas to flow through the second filter for regeneration of the second filter.

9. The post-processing system according to claim 8, further comprising: An oxidation catalyst is disposed upstream of the first filter; and A hydrocarbon introduction component configured to introduce hydrocarbons into the oxidation catalyst. The controller is further configured to instruct the hydrocarbon introduction assembly to introduce hydrocarbons into the oxidation catalyst to raise the temperature of the exhaust gas above the predetermined temperature threshold.

10. A filter assembly for removing particulate matter from exhaust gases produced by an engine, the filter assembly comprising: First filter; The second filter is located downstream of the first filter; as well as A valve having a first end positioned at the outlet of a first filter and a second end positioned at the inlet of a second filter. The valve is movable between a closed position and an open position, wherein in the closed position, all the exhaust gas flows through the second filter, and wherein in the open position, at least a portion of the exhaust gas flows through the valve and bypasses the second filter. The valve includes: Multiple rings, including: The first ring, which defines multiple first openings; and The second ring defines a plurality of second openings, and the second ring is adjacent to the first ring. In the closed position of the valve, the plurality of first openings and the plurality of second openings are misaligned to prevent fluid from flowing through the plurality of first openings and the plurality of second openings. In the open position of the valve, the second ring is rotated relative to the first ring so that the plurality of first openings and the plurality of second openings are aligned to allow fluid to flow through.

11. The filter assembly of claim 10, further comprising a bypass conduit fluidly connecting an exhaust gas flow path downstream of the first filter and upstream of the second filter to an exhaust gas flow path downstream of the second filter, wherein at least said portion of the exhaust gas flows through the bypass conduit in the said open position of the valve.

12. The filter assembly according to claim 11, wherein, The second filter has a smaller diameter than the first filter.

13. The filter assembly of claim 12, further comprising a housing, wherein the first filter, the second filter, and the valve are all positioned within the housing such that the bypass conduit is defined between an outer surface of the second filter and an inner surface of the housing.

14. An aftertreatment system configured to reduce components in exhaust gases produced by an engine, the aftertreatment system comprising: First filter; A second filter is disposed downstream of the first filter; A bypass duct that fluidly connects an exhaust gas flow path upstream of the first filter to an exhaust gas flow path between the first filter and the second filter; or fluidly connects an exhaust gas flow path between the first filter and the second filter to an exhaust gas flow path downstream of the second filter. A valve operably connected to the bypass conduit, the valve being movable between a closed position and an open position, in which the exhaust gas flows through the second filter, and in the open position, at least a portion of the exhaust gas flows through the bypass conduit to bypass the second filter; as well as A controller, operably coupled to the valve, is configured to: Determine whether the engine is operating under high particulate matter conditions or low particulate matter conditions; The valve is controlled such that during high-particulate-rate operating conditions of the engine, the valve is closed to a greater extent than during low-particulate-rate operating conditions of the engine, resulting in a greater portion of the exhaust gas passing through the second filter during high-particulate-rate operating conditions compared to low-particulate-rate operating conditions. This control of the valve ensures that the exhaust gas emitted from the aftertreatment system into the environment has a particulate matter content below a predetermined threshold. The valve is located at the inlet of the bypass pipe, and the valve includes: The first ring, which defines multiple first openings; and The second ring defines a plurality of second openings, and the second ring is adjacent to the first ring. In the closed position, the plurality of first openings are misaligned with the plurality of second openings, allowing the exhaust gas to flow through the second filter, and wherein the second ring is configured to rotate relative to the first ring to move the valve to the open position, in which the plurality of first openings are aligned with the plurality of second openings, allowing at least a portion of the exhaust gas to flow through the plurality of first openings and the plurality of second openings into the bypass duct located around the second filter.

15. The post-processing system according to claim 14, wherein, The first filter has a smaller pore size than the second filter, which makes the first filter have a higher filtration efficiency than the second filter.

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