System and method for managing mass flow distribution in post-processing systems

Abstract

A system, method, and apparatus are provided for managing mass flow distribution in a multi-branch aftertreatment system. In one embodiment, a system may include an aftertreatment system including first and second legs and a controller. The controller estimates a first mass flow in the first branch and a second mass flow in the second branch. The controller calculates an estimated total mass flow based on the estimated first mass flow and the estimated second mass flow. In response to determining that the estimated total mass flow is greater than the engine exhaust mass flow, the controller calculates a correction factor. The controller estimates a corrected first mass flow in the first branch and a corrected second mass flow in the second branch using the correction factor. The controller adjusts at least one of a reductant dosing, a hydrocarbon dosing, or a soot load estimate based on the corrected first mass flow and the corrected second mass flow.

Description

Technical Field

[0001] This application generally relates to aftertreatment systems and, more particularly, to managing mass flow split in an aftertreatment system.

[0002] Background

[0003] Internal combustion engines, such as diesel engines, emit exhaust gases that include nitrogen oxide (NO x ) compounds. It may be desirable to reduce, for example, NO x emissions to comply with environmental regulations. To reduce NO x emissions, a reducing agent can be dosed into the exhaust gas through a dosing system in an aftertreatment system. The reducing agent cooperates with the catalyst of a catalytic component to facilitate the conversion of a portion of the exhaust gas into non-NO x emissions, such as nitrogen (N 2 ), carbon dioxide (CO 2 ), and water (H 2 O), thereby reducing NO x emissions. In some applications, these compounds in the exhaust gas can be filtered or removed by one or more catalytic components (e.g., diesel oxidation catalyst (DOC) components, selective catalytic reduction (SCR) catalytic components, diesel particulate filter (DPF) components, ammonia oxidation (AMOx) catalytic components, etc.) located in the aftertreatment system.

[0004] Summary

[0005] Certain aftertreatment systems can include multiple legs for reducing exhaust by-products from an internal combustion engine. Each leg within the aftertreatment system has one or more components for reducing exhaust by-products, such as catalytic components (e.g., SCR catalytic components, DOC components, etc.) or filters (e.g., DPF components). The mass flow rate of the exhaust by-products through each leg can be used to determine the dosage of ammonia (NH 3 )(e.g., reducing agent) for reducing the exhaust by-products.

[0006] However, due to certain pipe restrictions or blockages within the aftertreatment system, the exhaust gas mass flow distribution between these branches may be uneven (e.g., the flow rate of exhaust gas in one branch may be different from that in another branch). The mass flow distribution refers to the ratio of the mass flow (or mass flow rate) distributed across the branches of the aftertreatment system. This restriction may be caused by many factors, including but not limited to asymmetric tailpipes or other improper installations of the aftertreatment system, soot load, deposits, etc. The restrictions within the aftertreatment system result in inaccuracies in mass flow estimation, which may at least affect the reductant dosing, hydrocarbon (HC) dosing, and / or soot load estimation. Therefore, inaccurate mass flow estimation may lead to, for example, NH 3 slip, premature or delayed regeneration triggering, and / or at least one of poor regeneration control. Accordingly, the systems, methods, and devices described herein are configured to identify any restrictions within the aftertreatment system and provide a correction to the mass flow estimation, thereby adjusting at least one of the reductant dosing, HC dosing, and / or soot load estimation according to the flow distribution to, for example, minimize reductant slip, untimely triggering of regeneration events, or poor regeneration control.

[0007] In some embodiments, an aftertreatment system includes: a first branch including one or more first aftertreatment components; a second branch including one or more second aftertreatment components; and a controller. The controller is configured to estimate a first mass flow of exhaust gas in the first branch. The controller is configured to estimate a second mass flow of exhaust gas in the second branch. The controller is configured to calculate an estimated total mass flow based on the estimated first mass flow and the estimated second mass flow. In response to determining that the estimated total mass flow is greater than the engine exhaust mass flow, the controller is configured to calculate a correction factor for balancing the estimated first mass flow and the estimated second mass flow. The controller is configured to use the correction factor to estimate a corrected first mass flow of exhaust gas in the first branch and a corrected second mass flow of exhaust gas in the second branch. The controller is configured to adjust at least one of the reductant dosing, hydrocarbon dosing, or soot load estimation based on the corrected first mass flow and the corrected second mass flow.

[0008] In some embodiments, the controller is configured to, in response to determining that the estimated total mass flow rate is greater than the engine exhaust mass flow rate and before calculating a correction factor, regenerate at least one of the following: a first selective catalytic reduction (SCR) catalyst in one or more first aftertreatment components or a second SCR catalyst in one or more second aftertreatment components. In some embodiments, after regenerating at least one of the first SCR catalyst or the second SCR catalyst and before calculating a correction factor, the controller is further configured to: estimate a third mass flow rate of the exhaust gas in the first branch; estimate a fourth mass flow rate of the exhaust gas in the second branch; and calculate a second estimated total mass flow rate based on the third mass flow rate and the fourth mass flow rate.

[0009] In some embodiments, in response to determining that the estimated total mass flow rate is greater than the engine exhaust mass flow rate, the controller is further configured to: determine whether the first branch or the second branch is newly installed; and calculate a correction factor in response to determining that the first branch or the second branch is newly installed. To calculate the correction factor, the controller is configured to: determine a ratio between a first pressure difference across a first particulate filter in one or more first aftertreatment components and a second pressure difference across a second particulate filter in one or more second aftertreatment components; and calculate the correction factor based on the ratio between the first pressure difference and the second pressure difference.

[0010] In some embodiments, in response to determining that the estimated total mass flow rate is greater than the engine exhaust mass flow rate, the controller is further configured to: determine whether the first branch or the second branch is newly installed; in response to determining that neither the first branch nor the second branch is newly installed, estimate a soot loading flow rate; and calculate a correction factor based on the estimated soot loading flow rate.

[0011] In some embodiments, the controller is further configured to estimate a first virtual mass flow rate of the exhaust gas in the first branch based on a first pressure difference across a first particulate filter in one or more first aftertreatment components. The controller is configured to estimate a second virtual mass flow rate of the exhaust gas in the second branch based on a second pressure difference across a second particulate filter in one or more second aftertreatment components. The controller is configured to calculate a correction factor based on at least one of the estimated first virtual mass flow rate or the estimated second virtual mass flow rate and the engine exhaust mass flow rate.

[0012] In some embodiments, the controller is further configured to: determine a first pressure difference across a first particulate filter in one or more first aftertreatment components and a second pressure difference across a second particulate filter in one or more second aftertreatment components within a time window including a plurality of time intervals. The controller is configured to: compare the first pressure difference and the second pressure difference with a set of calibrated tables, which includes a plurality of predetermined pressure differences for different flow allocations of the engine exhaust mass flow, in each of the plurality of time intervals. The controller is configured to: calculate a correction factor based on the comparison between the first pressure difference and the second pressure difference and the set of calibrated tables at the end of the time window.

[0013] In some embodiments, to calculate the correction factor, the controller is further configured to: increment the score of the calibrated table in the set of calibrated tables that matches the first pressure difference and the second pressure difference in each of the plurality of time intervals of the time window; and select the flow allocation corresponding to the calibrated table in the set of calibrated tables with the highest score to calculate the correction factor at the end of the time window.

[0014] In some embodiments, a method includes: estimating, by a controller, a first mass flow of exhaust gas in a first branch including one or more first aftertreatment components; estimating, by the controller, a second mass flow of exhaust gas in a second branch including one or more second aftertreatment components; calculating, by the controller, an estimated total mass flow based on the estimated first mass flow and the estimated second mass flow; calculating, by the controller, a correction factor for balancing the estimated first mass flow and the estimated second mass flow in response to determining that the estimated total mass flow is greater than the engine exhaust mass flow; estimating, by the controller, a corrected first mass flow of exhaust gas in the first branch and a corrected second mass flow of exhaust gas in the second branch using the correction factor; and adjusting, by the controller, at least one of reductant dosing, hydrocarbon dosing, or soot load estimation based on the corrected first mass flow and the corrected second mass flow.

[0015] In some embodiments, the method further includes: regenerating, by the controller, at least one of a first selective catalytic reduction (SCR) catalyst in one or more first aftertreatment components or a second SCR catalyst in one or more second aftertreatment components in response to determining that the estimated total mass flow is greater than the engine exhaust mass flow and before calculating the correction factor.

[0016] In some embodiments, after regenerating at least one of the first SCR catalyst or the second SCR catalyst and before calculating the correction factor, the method further includes: estimating, by a controller, a third mass flow rate of the exhaust gas in the first branch; estimating, by the controller, a fourth mass flow rate of the exhaust gas in the second branch; and calculating, by the controller, a second estimated total mass flow rate based on the third mass flow rate and the fourth mass flow rate.

[0017] In some embodiments, in response to determining that the estimated total mass flow rate is greater than the engine exhaust mass flow rate, the method includes: determining, by a controller, whether the first branch or the second branch is newly installed; and calculating, by the controller, a correction factor in response to determining that the first branch or the second branch is newly installed.

[0018] In some embodiments, calculating the correction factor includes: determining, by a controller, a ratio between a first pressure difference across a first particulate filter in one or more first aftertreatment components and a second pressure difference across a second particulate filter in one or more second aftertreatment components; and calculating, by the controller, the correction factor based on the ratio between the first pressure difference and the second pressure difference.

[0019] In some embodiments, in response to determining that the estimated total mass flow rate is greater than the engine exhaust mass flow rate, the method includes: determining, by a controller, whether the first branch or the second branch is newly installed; in response to determining that neither the first branch nor the second branch is newly installed, estimating, by the controller, a soot loading flow rate; and calculating, by the controller, a correction factor based on the estimated soot loading flow rate.

[0020] In some embodiments, the method further includes: estimating, by a controller, a first virtual mass flow rate of the exhaust gas in the first branch based on a first pressure difference across a first particulate filter in one or more first aftertreatment components; estimating, by the controller, a second virtual mass flow rate of the exhaust gas in the second branch based on a second pressure difference across a second particulate filter in one or more second aftertreatment components; and calculating, by the controller, a correction factor based on at least one of the estimated first virtual mass flow rate or the estimated second virtual mass flow rate and the engine exhaust mass flow rate.

[0021] In some embodiments, the method further includes: within a time window including a plurality of time intervals, determining, by a controller, a first pressure difference across a first particulate filter in one or more first aftertreatment components and a second pressure difference across a second particulate filter in one or more second aftertreatment components; in each of the plurality of time intervals, comparing, by the controller, the first pressure difference and the second pressure difference with a set of calibration tables, the set of calibration tables including a plurality of predetermined pressure differences for different flow allocations of engine exhaust mass flow; and at the end of the time window, calculating, by the controller, a correction factor based on the comparison between the first pressure difference and the second pressure difference and the set of calibration tables.

[0022] In some embodiments, calculating the correction factor includes: in each of the plurality of time intervals of the time window, in response to the first pressure difference and the second pressure difference matching one of the calibration tables in a set of calibration tables, incrementing, by the controller, the score of the calibration table in the set of calibration tables; and at the end of the time window, selecting, by the controller, the flow allocation corresponding to the calibration table in the set of calibration tables having the highest score to calculate the correction factor.

[0023] In some embodiments, an aftertreatment system includes: a first branch including one or more first aftertreatment components; a second branch including one or more second aftertreatment components; and a controller. The controller is configured to calculate a first NOx conversion efficiency of the first branch. The controller is configured to calculate a second NOx conversion efficiency of the second branch. The controller is configured to calculate an average NOx conversion efficiency based on the first NOx conversion efficiency and the second NOx conversion efficiency. The controller is configured to calculate the difference between the first NOx conversion efficiency and the second NOx conversion efficiency. In response to determining that the average NOx conversion efficiency is less than a first threshold or the difference between the first NOx conversion efficiency and the second NOx conversion efficiency is greater than a first threshold, the controller is configured to calculate an adjustment factor for balancing an estimated first mass flow and an estimated second mass flow. The controller is configured to use the adjustment factor to estimate an adjusted first mass flow of the exhaust gas in the first branch and an adjusted second mass flow of the exhaust gas in the second branch. The controller is configured to adjust at least one of reductant dosing, hydrocarbon dosing, or soot load estimation based on the adjusted first mass flow and the adjusted second mass flow.

[0024] In some embodiments, in response to determining that the average NOx conversion efficiency is less than a first threshold or the difference between the first NOx conversion efficiency and the second NOx conversion efficiency is greater than a first threshold, the controller is further configured to: identify a low NOx conversion efficiency branch from one of the first branch or the second branch based on the calculated first NOx conversion efficiency and the calculated second NOx conversion efficiency. The controller is configured to determine ammonia (NH3 ) Ratio (ANR) with NOx. The controller is configured to compare the ANR of the low NOx conversion efficiency branch with a second threshold. The controller is configured to identify NOx slip in response to determining that the ANR of the low NOx conversion efficiency branch is less than the second threshold, or to identify NH 3 slip in response to determining that the ANR of the low NOx conversion efficiency branch is greater than or equal to the second threshold. The controller is configured to calculate an adjustment factor based on the NOx slip or NH 3 slip to adjust the dosing rate of the reductant in the aftertreatment system.

[0025] In some embodiments, to adjust the dosing rate of the reductant, the controller is further configured to: increase the dosing rate of the reductant in the aftertreatment system by a first amount in response to NOx slip, or reduce the dosing rate of the reductant in the aftertreatment system by a second amount in response to NH 3 slip.

[0026] In some embodiments, the controller is further configured to calculate a third NOx conversion efficiency of the low NOx conversion efficiency branch after adjusting the dosing rate of the reductant. The controller is configured to readjust the dosing rate of the reductant in response to determining that the third NOx conversion efficiency is less than a third threshold.

[0027] In some embodiments, the controller is configured to calculate a fourth NOx conversion efficiency of the low NOx conversion efficiency branch after readjusting the dosing rate of the reductant. The controller is configured to trigger a fault in response to determining that the fourth NOx conversion efficiency is less than a fourth threshold.

[0028] In some embodiments, a method includes: calculating, by a controller, a first NOx conversion efficiency of a first branch including one or more first aftertreatment components; calculating, by the controller, a second NOx conversion efficiency of a second branch including one or more second aftertreatment components; calculating, by the controller, an average NOx conversion efficiency based on the first NOx conversion efficiency and the second NOx conversion efficiency; calculating, by the controller, a difference between the first NOx conversion efficiency and the second NOx conversion efficiency; in response to determining that the average NOx conversion efficiency is less than a first threshold or the difference between the first NOx conversion efficiency and the second NOx conversion efficiency is greater than a first threshold, calculating, by the controller, an adjustment factor for balancing an estimated first mass flow and an estimated second mass flow; estimating, by the controller, an adjusted first mass flow of the exhaust gas in the first branch and an adjusted second mass flow of the exhaust gas in the second branch using the adjustment factor; and adjusting, by the controller, at least one of reductant dosing, hydrocarbon dosing, or soot loading estimation based on the adjusted first mass flow and the adjusted second mass flow.

[0029] In some embodiments, in response to determining that the average NOx conversion efficiency is less than a first threshold or the difference between a first NOx conversion efficiency and a second NOx conversion efficiency is greater than a first threshold, the method further includes: identifying, by a controller, a low NOx conversion efficiency branch from one of a first branch or a second branch based on the calculated first NOx conversion efficiency and the calculated second NOx conversion efficiency; determining, by the controller, the ratio of ammonia (NH 3 ) to NOx (ANR) of the low NOx conversion efficiency branch; comparing, by the controller, the ANR of the low NOx conversion efficiency branch with a second threshold; identifying, by the controller, NOx slip in response to determining that the ANR of the low NOx conversion efficiency branch is less than the second threshold, or identifying NH 3 slip in response to determining that the ANR of the low NOx conversion efficiency branch is greater than or equal to the second threshold; and calculating, by the controller, an adjustment factor based on the NOx slip or NH 3 slip to adjust the dosing rate of a reductant in an aftertreatment system.

[0030] In some embodiments, adjusting the dosing rate of the reductant includes: increasing, by the controller, the dosing rate of the reductant in the aftertreatment system by a first amount in response to NOx slip, or decreasing, by the controller, the dosing rate of the reductant in the aftertreatment system by a second amount in response to NH 3 slip.

[0031] In some embodiments, the method further includes: calculating, by the controller, a third NOx conversion efficiency of the low NOx conversion efficiency branch after adjusting the dosing rate of the reductant; and readjusting, by the controller, the dosing rate of the reductant in response to determining that the third NOx conversion efficiency is less than a third threshold.

[0032] In some embodiments, the method further includes: calculating, by the controller, a fourth NOx conversion efficiency of the low NOx conversion efficiency branch after readjusting the dosing rate of the reductant; and triggering, by the controller, a fault in response to determining that the fourth NOx conversion efficiency is less than a fourth threshold. Brief Description of the Drawings

[0034] Details of one or more embodiments are set forth in the drawings and the detailed description below. Other features, aspects, and advantages of the present disclosure will become apparent from the specification, drawings, and claims, wherein:

[0035] Figure 1 is an example schematic diagram of an engine exhaust aftertreatment system coupled to a controller;

[0036] Figure 2 is Figure 1 an example schematic diagram of a controller for use with an engine system;

[0037] Figure 3 is an exemplary graph depicting the correlation between the mass flow distribution error and the restriction difference between branches;

[0038] Figure 4 is an exemplary graph depicting the correlation between the ammonia slip and the restriction difference between branches;

[0039] Figure 5 is an exemplary graph depicting the characteristics of the pressure difference and the volume flow rate (e.g., in actual cubic meters per second (ACMS)) with respect to certain flow rate distributions;

[0040] Figure 6 is another exemplary graph depicting the characteristics of the pressure difference and the volume flow rate with respect to certain flow rate distributions;

[0041] Figure 7 is an overview process flow diagram of an exemplary process for managing the mass flow distribution in a multi-branch aftertreatment system of an engine system for Figure 1 ;

[0042] Figure 8 is an exemplary process flow diagram of an exemplary proportionality correction for more specifically performing Figure 7 ;

[0043] Figure 9 shows a graph depicting certain exemplary operations associated with a correction process based on delta pressure for more specifically depicting Figure 8 ;

[0044] Figure 10 is a block diagram more specifically depicting an exemplary matching model for Figure 8 ;

[0045] Figure 11 is an exemplary graph depicting a model-based method for Figure 8 the inlet pipe restriction;

[0046] Figure 12 is an exemplary graph depicting a model-based method for Figure 8 the tail pipe restriction;

[0047] Figure 13 shows an exemplary graph depicting the monitoring data of a model-based method for Figure 8 matching 50-50 flow rate distribution data with the corresponding flow rate distribution table;

[0048] Figure 14 shows an exemplary graph depicting the monitoring data of a model-based method for Figure 8An example curve graph of monitoring data of a model-based method, matching 40 - 60 flow distribution data with the corresponding flow distribution table;

[0049] Figure 15 shows an example curve graph depicting monitoring data for a Figure 8 model-based method, matching 60 - 40 flow distribution data with at least one corresponding flow distribution table;

[0050] Figure 16 shows an example curve graph depicting monitoring data for a Figure 8 model-based method, matching test cell (TC) non-road transient cycle (NRTC) 50 - 50 flow distribution data with at least one corresponding flow distribution table;

[0051] Figure 17 is an overview process flow chart of another example process for mass flow distribution in a multi-branch aftertreatment system of an engine system for Figure 1 ;

[0052] Figure 18 is a process flow chart of an example process for managing mass flow distribution in a multi-branch aftertreatment system associated with Figure 17 as further described in detail; and

[0053] Figure 19 shows a curve graph of an example process for correction based on NOx monitoring associated with Figure 18 ;

[0054] It will be recognized that some or all of the figures are schematic representations for illustrative purposes. The figures are provided for the purpose of illustrating one or more embodiments and are expressly understood not to be used for limiting the scope or meaning of the claims.

[0055] Detailed Description

[0056] The following is a more detailed description of various concepts related to a method and apparatus for determining an efficiency value associated with a catalytic component, as well as embodiments of the method and apparatus. The various concepts introduced above and discussed in more detail below can be implemented in any of a variety of ways, as the described concepts are not limited to any particular implementation. Examples of specific embodiments and applications are provided primarily for illustrative purposes.

[0057] I. Overview

[0058] Internal combustion engines (e.g., diesel internal combustion engines, etc.) produce exhaust gas (e.g., sometimes referred to as waste gas). Depending on the fuel consumed by the internal combustion engine, the exhaust gas can contain different by-products (e.g., NO x, carbon monoxide (CO), unburned hydrocarbons (HC), etc.). By-products in the exhaust can be measured or sensed by one or more sensors of the aftertreatment system. For example, the density, volume, parts per million (ppm), etc. of the exhaust are measured. The aftertreatment system can be connected to the engine, for example, via an exhaust pipe connection from the engine. For simplicity, the examples herein may provide NO x as a by-product in the exhaust, and the sensor can be configured to sense NO downstream of the engine (e.g., at any position along the exhaust pipe) x emissions of NO x sensor. Although the described examples include NO x sensors for measuring NO x by-products, the described system can be applied to other sensors.

[0059] By-products in the exhaust can be reduced by one or more aftertreatment components of the engine system, which includes an aftertreatment system, such as a DOC component or an SCR catalyst component, as well as other types of catalysts. The aftertreatment system can include multiple branches. For simplicity, the examples herein provide an aftertreatment system including two branches. However, the aftertreatment system can include more than two branches having corresponding components for reducing exhaust by-products. For example, the exhaust can flow through or pass through the aftertreatment system via a first branch and a second branch. The catalyst components (e.g., SCR catalyst components, DOC components, etc.) of each branch can facilitate the chemical reaction between the by-products and the reductant to reduce or minimize the emissions from the tailpipe of the engine system. For simplicity, the examples herein may provide an SCR catalyst component or a DOC component as the catalyst component of the aftertreatment system. Each branch of the aftertreatment system can be supplied with ammonia (NH 3 )(e.g., reductant) to reduce exhaust by-products. The amount of reductant supplied can be based on the exhaust mass flow rate of the exhaust gas passing through the corresponding branch.

[0060] However, due to certain pipe restrictions or blockages within the aftertreatment system, the exhaust gas mass flow distribution between these branches may be uneven (e.g., the flow rate in one branch is different from that in another branch). The mass flow distribution refers to the ratio / rate / percentage of the mass flow (or mass flow rate) divided / assigned between the corresponding branches of the aftertreatment system. This restriction may be caused by many factors, including but not limited to asymmetric tailpipes or other improper installations of the aftertreatment system, soot loading, deposits, etc. Additionally, depending on the location of the restriction, the measured pressure value (e.g., the catalytic converter outlet pressure) that may be used to estimate the mass flow rate at the corresponding branch may not represent the actual mass flow rate of the branch. This results in inaccuracies in the mass flow rate estimation, which may at least affect the reductant dosing, hydrocarbon (HC) dosing, and / or soot loading estimation, etc. Therefore, inaccurate mass flow rate estimation may lead to, for example, NH 3 slip, premature or delayed regeneration triggering, and / or at least one of poor regeneration control. Accordingly, it is desirable to identify any restrictions within the aftertreatment system, calculate a correction / adjustment factor representing the actual mass flow distribution, and correct the estimated mass flow rate based on the actual flow distribution between the branches. For example, it is also desirable to subsequently adjust at least one of the reductant dosing, HC dosing, and / or soot loading estimation based on the flow distribution to minimize reductant slip, untimely triggering of regeneration events, or poor regeneration control.

[0061] The systems and methods described herein include at least one controller (e.g., a computing device or a data processing system), the at least one controller including at least one processor coupled to at least one memory. In some cases, the controller may be embedded in a system including an internal combustion engine, one or more sensors, and an aftertreatment system. In some cases, the controller may be external to the system, such as a server or a cloud computing device that communicates with one or more components of the system. In such a case, the controller is configured to receive data from the system, such as sensor data from sensors monitoring the internal combustion engine or the aftertreatment system.

[0062] In various arrangements, the controller is configured to calculate or estimate the mass flow of exhaust gas passing through a branch (e.g., a first branch and a second branch) of the aftertreatment system. The controller can estimate the mass flow based on pressure data (such as a pressure difference across the catalyst (e.g., Δ pressure) or an outlet pressure of the catalyst). The controller is configured to calculate an estimated total mass flow based on the estimated mass flow. The controller is configured to compare the estimated mass flow with the mass flow of exhaust gas from the engine to determine any flow distribution imbalance (e.g., uneven mass flow) between the branches. The imbalance may be caused by some type of restriction within the tail pipe or the aftertreatment system, such as deposits, soot loads, asymmetric tail pipes (by design or due to misalignment of at least one branch), etc. The controller is configured to calculate a correction factor to balance the estimated mass flow. The correction factor can be based on multiple variables, including: whether one or more components of the aftertreatment system have been regenerated, whether the aftertreatment system is newly installed, etc. By applying the correction factor to the estimated mass flow of each branch, the controller is configured to estimate the corrected mass flow of the branch and adjust at least one of the reductant dosing, hydrocarbon dosing, or soot load estimation accordingly. Therefore, the system and method can minimize NOx and reductant slip and control the regeneration trigger of one or more catalysts in an unbalanced aftertreatment system.

[0063] In some arrangements, the controller is configured to utilize the conversion efficiency (e.g., NO x conversion efficiency) to determine the imbalance between the branches and adjust the estimated mass flow. For example, the controller is configured to use, for example, NO x Sensors (e.g., monitoring NO x The NO of each branch is calculated. x Conversion efficiency. Based on the branch NO x conversion efficiency, the controller is configured to calculate the branch NO x The average conversion efficiency or NO x Then, if the average NO x At least one of the conversion efficiency or the difference is less than a corresponding threshold, the controller is configured to calculate an adjustment factor (e.g., sometimes referred to as a correction factor). The controller is configured to estimate an adjusted mass flow rate by applying the adjustment factor to an estimated flow rate (e.g., based on pressure data). Based on the adjusted mass flow rate across the first branch and the second branch, the controller is configured to adjust at least one of the reductant dosing (e.g., dosing duration, frequency, or timing), hydrocarbon dosing, or soot load estimation. Thus, the system and method can further minimize NO at the tailpipe. x and / or the amount of reducing agent and maintain NO x The conversion efficiency is higher than the expected efficiency level.

[0064] With these features, the embodiments described herein are capable of alerting a user to the use of impure fuel and are also capable of alerting the user that the aging of the catalytic component has exceeded a desired amount. Accordingly, the embodiments described herein can reduce the costs associated with warranty services and / or replacements that may be performed when the engine system consumes impure fuel.

[0065] II. Overview of a Multi-Branch Aftertreatment Engine System

[0066] Generally referring to the accompanying drawings, the various embodiments disclosed herein relate to systems, devices, and methods for managing mass flow distribution in a multi-branch aftertreatment system. Components in the aftertreatment system that reduce by-products in the exhaust (e.g., NO x , soot, etc.) include an SCR system that uses a two-step process to reduce harmful NO present in the exhaust or in a DOC component x emissions, for filtering or oxidizing hydrocarbons, carbon monoxide, or unburned fuel and oil. First referring to the SCR, a dispenser injects a reductant into the exhaust stream. The reductant can be urea, diesel exhaust fluid (DEF), aqueous urea solution (UWS), aqueous urea solution (e.g., AUS32, etc.) or another similar fluid. The reductant may decompose into NH 3 . Then, the mixture passes through an SCR catalytic component that, at a certain temperature, causes a reaction in the mixture to convert harmful NO x particles to pure nitrogen and water. In operation, un-decomposed reductant and un-reacted ammonia can be stored within the catalytic component (e.g., an SCR catalytic component) to chemically react with exhaust products (e.g., NO x particles, etc.).

[0067] The amount of reductant injected into the aftertreatment system (e.g., each branch of a multi-branch aftertreatment system) is at least partially based on an estimated exhaust gas mass flow rate. The mass flow rate can be estimated based on pressure data captured / sensed / measured by at least one pressure sensor in the aftertreatment system. However, if there are restrictions in the aftertreatment system, the estimated mass flow rate may be inaccurate. For example, certain system configurations can respond to a higher estimated mass flow rate with a higher reductant dispense amount (e.g., an increase in the rate or duration of reductant dispense) and respond to a lower estimated mass flow rate with a lower reductant dispense amount (e.g., a decrease in the rate or duration of reductant dispense). Due to the inaccuracy of the estimated mass flow rate, these system configurations may over-dispense in at least one branch, resulting in ammonia slip, or under-dispense in at least one branch, resulting in NO xEscape. Other factors affected by inaccurate mass flow estimates include, but are not limited to (listing only a few), premature or delayed triggering of catalyst regeneration, poor regeneration control (e.g., over- or under-dosing of hydrocarbons), or overload of at least one branch (e.g., soot and deposit loading). Thus, the systems and methods discussed herein can perform features and operations to estimate the flow distribution (e.g., mass flow) between the branches of the aftertreatment system, calculate correction / adjustment factors to adjust the estimated flow distribution, and adjust at least one of reductant dosing, hydrocarbon dosing, or soot load estimation, for example, based on the adjusted flow distribution.

[0068] Now referring to Figure 1 , a schematic diagram of a system 10 with a controller 100 is shown in accordance with an example embodiment. System 10 includes an internal combustion engine 20 (hereinafter referred to as the "engine") coupled to an exhaust aftertreatment system 22, which is in exhaust receiving communication with the engine. As shown, the exhaust aftertreatment system 22 consists of a plurality of branches (e.g., a first branch 22A and a second branch 22B), each branch including one or more corresponding components of the exhaust aftertreatment system. Although two branches are shown and described for the purposes of the examples herein, the exhaust aftertreatment system 22 can include more than two branches formed by additional components of the exhaust aftertreatment system 22. The controller 100 is coupled to or communicates with the system 10 and an operator input / output (I / O) device 120. The system 10 can be embodied in a vehicle. The vehicle can be an on-road vehicle or an off-road vehicle, including but not limited to long-haul trucks, mid-size trucks (e.g., pickup trucks), automobiles, boats, tanks, airplanes, locomotives, mining equipment, and any other type of vehicle. The vehicle can include a transmission, a fuel system, one or more additional vehicle subsystems, etc. In this regard, the vehicle can include more, fewer, and / or different components / systems such that the principles, methods, systems, devices, processes, etc. of the present disclosure are intended to apply to any other vehicle configuration. It should also be understood that the principles of the present disclosure should not be construed as limited to vehicles; rather, the present disclosure also applies to several fixed installations such as generators or generator sets.

[0069] The engine 20 can be a compression ignition internal combustion engine that utilizes diesel fuel. In various other embodiments, the engine 20 can be configured as any other type of engine (e.g., spark ignition) that utilizes any type of fuel (e.g., gasoline, natural gas, etc.). In some embodiments, the vehicle can be another type of vehicle, such as a hybrid vehicle that includes one or more electric motors, a fuel cell vehicle, etc. Thus, while the engine 20 is configured herein as a diesel-powered internal combustion engine, other embodiments are contemplated to fall within the scope of the present disclosure.

[0070] Within the internal combustion engine 20, air from the atmosphere combines with fuel and burns to power the engine. Combustion of the fuel and air in the compression chamber of the engine 20 produces exhaust gases that are operably discharged to an exhaust manifold (not shown) and a post-treatment system 22.

[0071] Each of the branches (e.g., the first branch 22A and the second branch 22B) of the exhaust after-treatment system 22 includes a diesel oxidation catalyst (DOC) member 30, a diesel particulate filter (DPF) member 40, a selective catalytic reduction (SCR) system 52 having an SCR catalyst member 50, and an ammonia oxidation (AMOx) catalyst member 60. The first branch 22A includes a DOC member 30A, a DPF member 40A, an SCR system 52A having a first SCR catalyst member 50A, and an AMOx catalyst member 60A. The second branch 22B includes a DOC member 30B, a DPF member 40B, an SCR system 52B having a second SCR catalyst member 50B, and an AMOx catalyst member 60B. For simplicity, the components of the respective branches described herein can generally be labeled, for example, as the DOC member 30, the DPF member 40, the SCR system 52 having the respective SCR catalyst member 50, and the AMOx catalyst member 60 associated with the respective first branch 22A or second branch 22B.

[0072] The exhaust after-treatment system 22 further includes an exhaust gas recirculation (EGR) system 70. The SCR systems 52A and 52B of the respective branches further include a reductant delivery system that has a diesel exhaust fluid (DEF) source 54A - 54B (e.g., the DEF source 54 of the branch), which supplies DEF to a DEF dispenser 56A - 56B (e.g., the dispenser 56 generally referred to for the first branch 22A and the second branch 22B) via DEF lines 58A - 58B, respectively.

[0073] In the exhaust gas flow direction indicated by the direction arrow 29, the exhaust gas flows from the engine 20 into the inlet duct 24 of the exhaust aftertreatment system 22. In the first branch 22A, the exhaust gas flows from the inlet duct 24 into the DOC component 30 and exits the DOC component 30 into the first section 28A of the exhaust duct. The exhaust gas flows from the first section 28A of the exhaust duct into the DPF component 40 and exits the DPF component 40 into the second section 28B of the exhaust duct. The exhaust gas flows from the second section 28B of the exhaust duct into the SCR catalyst component 50 and exits the SCR catalyst component 50 into the third section 28C of the exhaust duct. When the exhaust gas flows through the second section 28B of the exhaust duct, DEF (or reductant) is periodically dispensed into it by the DEF (or reductant) dispenser 56. Accordingly, the second section 28B of the exhaust duct serves as a decomposition chamber or tube to facilitate the decomposition of DEF into ammonia. The exhaust gas flows from the third section 28C of the exhaust duct into the AMOx catalyst component 60 and exits the AMOx catalyst component 60 into the outlet duct 26 before the exhaust gas is discharged from the aftertreatment system 22. Similarly, in the second branch 22B, the exhaust gas flows through the ducts 28D - 28F, which pass through various components in the second branch 22B and enter the outlet duct 26.

[0074] Based on the foregoing, in the illustrated embodiment, the DOC component 30 (e.g., DOC component 30A or DOC component 30B) is positioned upstream of the DPF component 40 (e.g., DPF component 40A or DPF component 40B) and the SCR catalyst component 50 (e.g., SCR catalyst component 50A or SCR catalyst component 50B), and the SCR catalyst component 50 (e.g., SCR catalyst component 50A or SCR catalyst component 50B) is positioned downstream of the DPF component 40 (e.g., DPF component 40A or DPF component 40B) and upstream of the AMOx catalyst component 60 (e.g., AMOx catalyst component 60A or AMOx catalyst component 60B). However, in alternative embodiments, other arrangements of the components of the exhaust aftertreatment system 22 are possible. Additionally, and for simplicity, the components of one branch in the exhaust aftertreatment system 22 may be similar to those of the other branch. Alternatively, one or more components or the arrangement of components in the first branch 22A may be different from those in the second branch 22B, and so on.

[0075] The DOC component 30 can be configured to have any number of different types of flow-through designs. The DOC component 30 can be configured to oxidize at least some particulate matter in the exhaust gas (e.g., the soluble organic fraction of soot) and reduce unburned hydrocarbons and CO in the exhaust gas to compounds that are less harmful to the environment. For example, the DOC component 30 can be configured to reduce the hydrocarbon concentration and CO concentration in the exhaust gas to meet the necessary emission standards for those components of the exhaust gas. An indirect result of the oxidation ability of the DOC component 30 is the ability of the DOC component 30 to oxidize NO to NO 2 . In this way, in addition to the NO converted from NO by the DOC component 30, the NO 2 leaving the DOC component 30 2 is equal to the NO in the exhaust gas generated by the engine 20 2 .

[0076] In addition to treating the hydrocarbon concentration and CO concentration in the exhaust gas, the DOC component 30 can also be used for the controlled regeneration of the DPF component 40, the SCR catalyst component 50, and the AMOx catalyst component 60. This can be achieved by injecting or dosing unburned HC into the exhaust gas upstream of the DOC component 30. When in contact with the DOC component 30, the unburned HC undergoes an exothermic oxidation reaction, which causes the temperature of the exhaust gas leaving the DOC component 30 and subsequently entering the DPF component 40, the SCR catalyst component 50, and / or the AMOx catalyst component 60 to increase. The amount of unburned HC added to the exhaust gas is selected to achieve the desired temperature increase or the target controlled regeneration temperature.

[0077] The DPF component 40 can be any of a variety of flow-through designs and is configured to reduce the particulate matter concentration (e.g., soot and ash) in the exhaust gas to meet the necessary emission standards. The DPF component 40 captures particulate matter and other components and can therefore be regenerated periodically to burn off the captured components. Additionally, the DPF component 40 can be configured to oxidize NO to form NO independently of the DOC component 30 2 .

[0078] As described above, the SCR system 52 includes a reductant delivery system. The reductant delivery system includes a source 54 of reductant (e.g., DEF), a pump (not shown), and a dispenser 56 (e.g., sometimes referred to as a delivery mechanism 56). The reductant source 54 can be capable of holding a reductant such as ammonia (NH 3) containers or tanks for DEF (such as urea), diesel, etc.). The reductant source 54 is in supply communication with a pump configured to pump the reductant from the reductant source 54 to the delivery mechanism 56 via a reductant delivery line 58. The delivery mechanism 56 is located upstream of the SCR catalyst member 50. The delivery mechanism 56 is selectively controllable to directly inject the reductant into the exhaust stream prior to the exhaust stream entering the SCR catalyst member 50. As described herein, the controller 100 is configured to control the timing and amount of reductant delivered to the exhaust, for example, based on the estimated or calculated mass flow rate across each branch of the exhaust aftertreatment system 22. The reductant can decompose to produce ammonia. As briefly described above, in the presence of the SCR catalyst member 50, ammonia reacts with NO x to react, with NO x reduced to less harmful emissions such as N 2 and H 2 O. The NO x in the exhaust stream includes NO 2 and NO. In the presence of NH 3 , both NO 2 and NO are reduced to N 2 and H 2 O through various chemical reactions driven by the catalytic elements of the SCR catalyst member.

[0079] In some embodiments, the SCR catalyst member 50 is a vanadium-based catalyst member, and in other embodiments, the SCR catalyst member is a zeolite-based catalyst member, such as a copper zeolite (Cu-Ze) or iron zeolite (Fe-Zu) catalyst member. In one representative embodiment, the reductant is aqueous urea and the SCR catalyst member 50 is a zeolite-based catalyst member. In other embodiments, the reductant includes a first reductant and a second reductant, where the first reductant is urea and the second reductant is ammonia.

[0080] The AMOx catalyst member 60 can be any of a variety of flow-through catalyst members configured to react with ammonia to primarily produce nitrogen. As briefly described above, the AMOx catalyst member 60 is configured to remove ammonia that has escaped through or left the SCR catalyst member 50 without reacting with the NOx in the exhaust. In some cases, the aftertreatment system 22 can operate with or without the AMOx catalyst member. Additionally, although the AMOx catalyst member 60 is shown in Figure 1 as a unit separate from the SCR system 52, in some embodiments, the AMOx catalyst member can be integrated with the SCR catalyst member (e.g., the AMOx catalyst member and the SCR catalyst member can be located within the same housing). As described herein, the SCR catalyst member 50 and the AMOx catalyst member 60 form an SCR and AMOx system.

[0081] System 10 (e.g., the aftertreatment system 22) includes various sensors. For example, the aftertreatment system 22 includes a NO x sensor 12. The aftertreatment system 22 includes a temperature sensor 14. The aftertreatment system 22 includes a pressure sensor 16. The sensors can be strategically disposed throughout the aftertreatment system 22, such as upstream, downstream, or at one or more of the catalytic converters (e.g., the DOC component 30, the DPF component 40, the SCR catalytic converter component 50, and / or the AMOx catalytic converter component 60). The sensors can communicate with the controller 100 and be configured to monitor the operating conditions of the system 10. It should be understood that one or more NOx sensors, pressure sensors, temperature sensors, and various other sensors (oxygen sensors, exhaust component sensors, NH 3 sensors) can also be included in the system and be disposed at various locations.

[0082] As shown, one or more pressure sensors 16 can be positioned upstream and downstream of the catalytic converter component. In this configuration, the pressure sensor 16 measures at least one of the outlet pressure, the inlet pressure, or the pressure at the catalytic converter component (e.g., a pressure sensor 16 (not shown) inside the catalytic converter component). For simplicity and for the purposes of the examples herein, the DPF component 40 can be provided as the catalytic converter component whose pressure data is monitored for estimating the mass flow or flow rate of the exhaust gas. However, for example, the pressure sensor 16 can be positioned upstream, downstream, or at another catalytic converter component (such as the SCR catalytic converter component 50, the DOC component 30, or the AMOx catalytic converter component 60). The pressure data is used by the controller 100 to estimate the mass flow.

[0083] In addition, more than one NOx sensor can be positioned upstream and downstream of the catalytic converter component. In some configurations, one NO x sensor 12 measures the engine-out NO x while another NO x sensor 12 measures the inlet NO of the SCR catalytic converter component 50 x amount. This is because the DOC component 30 / DPF component 40 potentially oxidizes a certain portion of the engine-out NO x such that the engine-out NO x amount will not be equal to the inlet NO of the SCR catalytic converter component 50 x amount. Therefore, this configuration accounts for this potential difference. The NO amount exiting the SCR catalytic converter component 50 can be measured by the NO x sensor 12 located downstream of the SCR catalytic converter component 50 and / or by the NO located downstream of the AMOx catalytic converter component 60 x sensor 12x The sensor 12 measures NO. x The sensor 12 (in some embodiments, x the sensor 12) is positioned downstream of the SCR catalyst member 50 and is configured to detect NO in the exhaust gas downstream of the SCR catalyst member (e.g., exiting the SCR catalyst member). x concentration. From the NO x sensor 12, the measurement results (e.g., the measured NO x data) are used by the controller 100 to determine the NO x conversion efficiency across the corresponding branch of the aftertreatment system 22. x The NO conversion efficiency corresponds to the amount of NO reduced across one or more components of the aftertreatment system 22. x Although the NO x sensor 12 is shown at the outlet of the engine 20, the corresponding NO x sensor 12 can be disposed upstream of the corresponding DOC member 30 or DPF member 40 of each branch.

[0084] The temperature sensor 14 is associated with one or more catalyst members. The temperature sensor 14 is strategically positioned to detect the temperature of the exhaust gas flowing into the DOC member 30 (e.g., the temperature of the exhaust pipe upstream of the catalyst member), the temperature of the exhaust gas flowing out of the DOC member 30 (e.g., the temperature of the exhaust pipe downstream of the catalyst member), and the temperature of the exhaust gas flowing into another catalyst member (e.g., from the DOC member 30 to the DPF member 40) and flowing out of the DPF member 40, and then dosed with DEF by the dispenser 56. In some embodiments, at least one temperature sensor 14 can be configured as part of the catalyst member itself to directly measure the bed temperature of the catalyst member.

[0085] The EGR system 70 is configured to recirculate exhaust gas back to the intake manifold of the engine 20 for combustion. The EGR system 70 includes an EGR cooler 74 and an EGR valve 76. In some applications, the EGR cooler 74 can be, for example, an air - air and / or liquid (e.g., coolant) - air (e.g., exhaust) heat exchanger. The EGR cooler 74 is configured to remove heat from the exhaust gas before the exhaust gas is re - introduced into the intake manifold. Heat is removed from the exhaust gas before re - introduction, among other reasons, to prevent high intake temperatures that could promote pre - ignition (e.g., engine knock).

[0086] Although the illustrated exhaust aftertreatment system 22 includes a DOC component 30, a DPF component 40, an SCR catalyst component 50, and an AMOx catalyst component 60 positioned at particular locations relative to each other along an exhaust flow path, in other embodiments, the exhaust aftertreatment system can include more than one of the DOC component 30, the DPF component 40, the SCR catalyst component 50, and the AMOx catalyst component 60 positioned at various locations relative to each other along the exhaust flow path.

[0087] Figure 1 is also shown to include an operator input / output (I / O) device 120. The operator I / O device 120 is communicatively coupled to the controller 100 such that information can be exchanged between the controller 100 and the I / O device 120. The information exchanged between the controller 100 and the I / O device 120 can relate to Figure 1 one or more components of or any determination of the controller 100 disclosed herein. The operator I / O device 120 enables an operator of the vehicle (e.g., a passenger, etc.) to communicate with the controller 100 and other components of the vehicle, such as those shown in Figure 1 . For example, the operator I / O device 120 can include an interactive display, a touchscreen device, one or more buttons and switches, a voice command receiver, etc. In some cases, the I / O device 120 can be part of a vehicle that includes the engine 20 and the aftertreatment system 22. In some other cases, the I / O device 120 can be a remote device accessible to the operator, such as via a client device. In some aspects, the I / O device 120 can be a server that receives data from the vehicle's controller 100.

[0088] The controller 100 is configured to monitor operations, conditions, or events within the system 10 (e.g., components of the aftertreatment system 22). The controller 100 is configured to control at least in part the operation of the system 10 and associated subsystems, such as the internal combustion engine 20 and the exhaust aftertreatment system 22. Communication between and among components can occur via any number of wired or wireless connections. For example, a wired connection can include a serial cable, a fiber optic cable, a CAT5 cable, or any other form of wired connection. In contrast, a wireless connection can include the Internet, Wi-Fi, cellular, radio, Bluetooth, etc. In one embodiment, a controller area network (“CAN”) bus provides the exchange of signals, information, and / or data. The CAN bus includes any number of wired and wireless connections. Because the controller 100 is communicatively coupled to Figure 1 the systems and components of, the controller 100 is configured to receive data from Figure 1 one or more of the components shown in. For example, the data can include NO xData (e.g., from NO x Sensor 12 input NO x Amount and from NO x Output of sensor 12 is NO x The data may include information such as the amount of air delivered to the dispenser 56, the timing and amount of the air delivered to the dispenser 56, and vehicle operation data received via one or more sensors (e.g., engine speed, vehicle speed, engine temperature, flow, etc.). As another example, the data may include input from the operator input / output device 120. Using this data, the controller 100 monitors the multi-branch aftertreatment system 22 to determine if there is a restriction that causes an imbalance in the flow distribution across the various branches, and diagnoses the imbalance to minimize reductant slip and NO x Escape and optimize regeneration control or triggering. Figure 2 The structure, function or configuration of the controller 100 is further described.

[0089] Figure 2 The controller 100 includes a processing circuit 101, which includes a processor 102, a memory 103, and various circuits, including at least an engine circuit 105, an ammonia circuit 106, and a NO x Circuit 107, flow circuit 108, correction circuit 109, modeling circuit 110 and adjustment circuit 111. Processor 102 can be implemented as an application specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGA), a digital signal processor (DSP), a group of processing components, or other suitable electronic processing components. Memory 103 (e.g., RAM, ROM, flash memory, hard disk storage device, etc.) can store data and / or computer code to facilitate the various processes described herein. Memory 103 can be communicatively connected to processor 102 and one or more circuits. In various embodiments, memory 103 includes engine circuit 105, ammonia circuit 106, NO x Circuit 107, flow circuit 108, correction circuit 109, modeling circuit 110 and adjustment circuit 111. Memory 103 is configured to provide computer code or instructions to processor 102 for performing the processes described with respect to controller 100 herein. In addition, memory 103 can be or include tangible, non-transitory volatile memory or non-volatile memory. Thus, memory 103 can include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described herein.

[0090] The controller 100 includes a communication interface 104. The communication interface 104 can include any combination of wired and / or wireless interfaces (e.g., jacks, antennas, transmitters, receivers, transceivers, wired terminals) for data communication with various systems, devices, or networks, which are configured to enable in-vehicle communication (e.g., communication between and among components of a vehicle) and out-of-vehicle communication (e.g., direct communication with a remote computing system). In this regard, in some embodiments, the communication interface 104 includes a network interface. The network interface is used to establish a connection with other computing devices via a network. The network interface includes program logic facilitating the connection of the controller 100 to the network. The network interface includes any combination of a wireless network transceiver (e.g., a cellular modem, a Bluetooth transceiver, a Wi-Fi transceiver) and / or a wired network transceiver (e.g., an Ethernet transceiver). In some arrangements, the network interface includes hardware and machine-readable media sufficient to support communication over multiple data communication channels. Additionally, in some arrangements, the network interface includes encryption capabilities for establishing a secure or relatively secure communication session, where data transmitted through the session is encrypted. For example, with respect to out-of-vehicle communication, the communication interface 104 can include an Ethernet card and port for sending and receiving data via an Ethernet-based communication network and / or a Wi-Fi transceiver for communicating via a wireless communication network. The communication interface 104 can be configured to communicate via a local area network and / or a wide area network (e.g., the Internet) and can use various communication protocols (e.g., IP, LON, Bluetooth, ZigBee, and radio, cellular, near field communication). Additionally, the communication interface 104 can work in conjunction with or in series with a telematics unit (if included) to communicate with other vehicles in a fleet and / or a remote computing system.

[0091] The controller 100 is configured to receive inputs (e.g., signals, information, data, etc.) from the components / systems of the system 10 and / or the operator I / O device 120. Thus, the controller 100 is configured to at least partially control the components / systems of the system 10 and the associated engine 20. Since Figure 2 the components can be included in a vehicle, the controller 100 can be configured as one or more electronic control units (ECUs). The controller 100 can be separate from or included with at least one of a transmission control unit, an exhaust aftertreatment control unit, a powertrain control module, an engine control module, etc. In some cases, the controller 100 can be a device remote from the vehicle, such as a remote controller configured to control one or more components of the system 10 or communicate with the one or more components.

[0092] In one configuration, one or more of the engine circuit 105, the ammonia circuit 106, the NO x circuit 107, the flow circuit 108, the calibration circuit 109, the modeling circuit 110, or the adjustment circuit 111 may be implemented as a machine or computer-readable medium that stores instructions executable by a processor (such as processor 102) and stored in a memory device (such as memory 103). As described herein and in other uses, the machine-readable medium facilitates performing certain operations to enable the receipt and transmission of data. For example, the machine-readable medium may provide instructions (e.g., commands, etc.) to, for example, collect data. In this regard, the machine-readable medium may include programmable logic that defines the data collection (or data transmission) frequency. The computer-readable medium may include code that may be written in any programming language, including but not limited to Java, etc., and any conventional procedural programming language, such as the "C" programming language or a similar programming language. The computer-readable program code may be executed on one processor or multiple remote processors. In the latter case, the remote processors may be interconnected by any type of network (e.g., CAN bus, etc.).

[0093] In another configuration, one or more circuits are implemented as a hardware unit, such as an electronic control unit. For example, one or more circuits may be implemented as one or more circuit components, including but not limited to processing circuits, network interfaces, peripherals, input devices, output devices, sensors, etc. In some embodiments, one or more circuits may take the form of one or more analog circuits, electronic circuits (e.g., integrated circuits (ICs), discrete circuits, system-on-chip (SOC) circuits, microcontrollers, etc.), telecommunication circuits, hybrid circuits, and any other type of "circuit". One or more circuits may include any type of component for completing or facilitating the implementation of the operations described herein. For example, the circuits 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. One or more circuits may also include programmable hardware devices, such as field-programmable gate arrays, programmable array logic, programmable logic devices, etc. One or more circuits may include one or more memory devices for storing data that may be used by the respective circuits (e.g., the engine circuit 105, the ammonia circuit 106, the NO xInstructions executed by a processor of circuit 107, flow circuit 108, calibration circuit 109, modeling circuit 110, and adjustment circuit 111). One or more memory devices and the processor may have the same definitions as provided below for memory 103 and processor 102. In some hardware unit configurations, one or more circuits may be geographically dispersed in separate locations in, for example, a vehicle. Alternatively and as shown, one or more circuits may be embodied in or within a single unit / case, which is shown as controller 100.

[0094] In the example shown, controller 100 includes processing circuit 101, which has engine circuit 105, ammonia circuit 106, NO x circuit 107, flow circuit 108, calibration circuit 109, modeling circuit 110, and adjustment circuit 111. Processing circuit 101 may be constructed or configured to execute or implement the instructions, commands, and / or control processes described herein with respect to one or more circuits. The depicted configuration represents engine circuit 105, ammonia circuit 106, NO x circuit 107, flow circuit 108, calibration circuit 109, modeling circuit 110, and adjustment circuit 111 as instructions in a machine or computer-readable medium. In some embodiments, the instructions may be stored by a memory device. However, as described above, this illustration is not meant to be limiting, as the present disclosure contemplates other embodiments in which engine circuit 105, ammonia circuit 106, NO x circuit 107, flow circuit 108, calibration circuit 109, modeling circuit 110, and adjustment circuit 111, or at least one of the one or more circuits, is configured as a hardware unit. All such combinations and variations are intended to fall within the scope of the present disclosure.

[0095] In the example shown, for example, controller 100 includes at least: engine circuit 105 configured to control engine 20; ammonia circuit 106 in communication with sensors associated with SCR catalyst member 50 and / or AMOx catalyst member 60; NO x circuit 107 in communication with NO x sensor 12; flow circuit 108 in communication with pressure sensor 16 to estimate the mass flow rate through aftertreatment system 22; calibration circuit 109 configured to calculate a correction factor and apply the correction factor to the estimated mass flow rate; modeling circuit 110 in communication with other circuits and configured to manage a model of a predefined flow rate and its corresponding correction factor to be used by calibration circuit 109; and adjustment circuit 111, which is in communication with other circuits and configured to adjust at least one of reductant dosing control, hydrocarbon control, or soot loading estimation based on the correction factor applied to the estimated mass flow rate.

[0096] The engine circuit 105 is configured to receive information from a user or operator (e.g., via the operator input / output device 120) and provide instructions to or otherwise control the engine 20. For example, the engine circuit 105 can control the operation or components of the engine, including at least an intake valve for controlling intake air or gas, an exhaust valve for releasing exhaust gas through pipes (e.g., pipes 24, 28A - 28F, 26, etc.), or other components of the engine 20. Thus, the engine circuit 105 can control the torque and / or speed of the engine 20. The engine circuit 105 is configured to receive information associated with the engine 20, such as fuel supply amount, temperature, etc. The engine circuit 105 is configured to transmit engine information to one or more other circuits of the controller 100 (e.g., the ammonia circuit 106, the NO x circuit 107, the flow circuit 108, the calibration circuit 109, the modeling circuit 110, the adjustment circuit 111, etc.) and components of the memory 103.

[0097] For example, the ammonia circuit 106 is configured to communicate with the dispenser 56, the temperature sensor 14, and the NO x sensor 12 to determine the amount of ammonia (or reductant) stored in the SCR catalyst member 50. In some cases, the ammonia circuit 106 is configured to control the dispenser 56 to supply or introduce the reductant into the pipeline. In such cases, the ammonia circuit 106 is configured to determine the reductant dosing rate, including duration, frequency, and timing. Thus, the ammonia circuit 106 can use at least one of the reductant dosing rate and data from one or more other circuits to determine the amount of reductant stored in the SCR catalyst member 50, such as the amount of NO x at the inlet of the SCR catalyst member 50 and the amount of NO x at the outlet of the SCR catalyst member 50 (e.g., the amount of NO x converted by the catalyst member) and / or the mass flow rate in the corresponding branch.

[0098] NO x The NO x circuit 107 is coupled to the NO x sensor 12 and communicates with the NO x sensor 12, and provides information about the NO x level to other circuits of the controller 100 and components of the memory 103. One or more NO x sensors can be virtual NO x sensors or physical NO x sensors. In addition to other sensor data, the NO xThe raw data received by sensor 12 to provide information indicating NO x level to other circuits of controller 100 and components of memory 103.

[0099] Flow circuit 108 is coupled to and communicates with pressure sensor 16, and provides information about the pressure magnitude or other pressure data to other circuits of controller 100 and components of memory 103. One or more pressure sensors can be virtual pressure sensors or physical pressure sensors. In addition to other sensor data, flow circuit 108 can also process the raw data received from pressure sensor 16 to provide information indicating the pressure level to other circuits of controller 100 and components of memory 103. For example, using the pressure data, flow circuit 108 is configured to estimate the mass flow corresponding to the location of pressure sensor 16.

[0100] Calibration circuit 109 is configured to communicate with other circuits, including receiving data from at least one of the following circuits: NO x circuit 107 (e.g., NO x measurement results) or flow circuit 108 (e.g., pressure data or mass flow data). Calibration circuit 109 is configured to calculate a calibration factor (e.g., sometimes referred to as an adjustment factor) for adjusting the estimated mass flow based on the pressure data. For example, calibration circuit 109 is configured to receive estimates of the mass flow across the individual branches of post-processing system 22. Calibration circuit 109 is configured to identify an unbalanced flow distribution due to a restriction when the total estimated mass flow across the branches is not within the range of the engine exhaust mass flow. If there is an imbalance or inaccuracy in the estimated mass flow, calibration circuit 109 is configured to use the techniques and operations described herein to calculate a calibration factor for calibrating or diagnosing the estimated mass flow. In various embodiments, calibration circuit 109 is configured to consider SCR deposition (e.g., whether regeneration is performed), newly installed systems, and balanced flow distribution due to accumulated soot load.

[0101] The modeling circuit 110 is configured to manage a model representing a predefined flow distribution of the aftertreatment system 22. The model can be stored in the memory 103 or a remote database. The modeling circuit 110 is configured to retrieve the model from the memory 103 or the remote database. The modeling circuit 110 is configured to modify or adjust the model given any updated information from the operator I / O device 120. The flow distribution associated with each model can be predefined, such as 50-50 (e.g., 50% of the engine exhaust mass flow across the first branch 22A and 50% of the exhaust mass flow across the second branch 22B), 65-35 (e.g., 65% across the first branch 22A and 35% across the second branch 22B), 55-45 (e.g., 55% across the first branch 22A and 45% across the second branch 22B), etc. Each model corresponding to a predefined flow distribution can be associated with a respective correction factor (e.g., predetermined for the respective flow distribution and pressure data). The correction factor can be a multiplier, a percentage, or an amount of mass flow to increase or decrease the estimated mass flow of at least one of the branches based on the flow distribution estimate. The modeling circuit 110 is configured to compare pressure data (e.g., catalytic converter output pressure or pressure differential across a catalytic converter component) representing an estimated flow distribution with various models over time. The modeling circuit 110 is configured to select at least one model in the models having a predefined flow distribution similar to the estimated flow distribution. The modeling circuit 110 is configured to transmit or provide the correction factor of the selected model to the correction circuit 109 for adjusting the estimated mass flow.

[0102] The adjustment circuit 111 is configured to communicate with other circuits including the ammonia circuit 106, NO x circuit 107, the flow circuit 108, the correction circuit 109, etc. The adjustment circuit 111 communicates with the other circuits to obtain information including at least one of the following: NO x conversion efficiency, mass flow estimate, amount of stored reductant (e.g., ammonia), NO generated by the engine x amount, amount of NO in each branch x amount, correction factor, etc. In some cases, the adjustment circuit 111 communicates directly with components of the system, including sensors, dispenser 56, or other components. Using the information obtained from the system, the adjustment circuit 111 is configured to adjust at least one of the estimated mass flow, the dosing rate of the reductant, the hydrocarbon injection (e.g., regeneration) timing, or the soot load estimate by applying the correction factor. The adjustment of the dosing rate, regeneration timing, or soot load estimate is at least partially based on the adjusted estimated mass flow, which represents the amount of exhaust by-products passing through the branches of the aftertreatment system 22. As described herein, one or more circuits of the controller 100 are configured to detect and diagnose an imbalance within the aftertreatment system 22.

[0103] Reference Figure 3 , depicts an example graph 300, which shows the correlation between the mass flow distribution error and the difference in restrictions between the branches. The x-axis can represent the difference in restrictions between the branches (e.g., at a certain rated flow rate, the ratio of the restriction in one branch to the restriction in another branch or the tailpipe pressure drop Δ), and the y-axis can represent the error level of the mass flow distribution ratio. For example, in some systems, there may be restrictions at the tailpipe outlet of the system. In such a system, an increase in the difference in restrictions between the branches (e.g., one branch has more restrictions compared to another branch) can lead to a greater error in the flow distribution ratio (e.g., an error in the mass flow estimation between the branches). As shown, an increase in the error (e.g., the Δ value increases from zero) can be proportional to an increase in the difference in restrictions (e.g., an increase in the tailpipe pressure drop Δ between the branches). An increase in the error represents a decrease in the accuracy of the determined mass flow distribution ratio. In this case, as the value in the y-axis of graph 300 decreases (e.g., the accuracy decreases or the error increases), as regarding Figure 4 shown, more NH 3 escapes from the tailpipe.

[0104] Reference Figure 4 , depicts an example graph 400, which shows the correlation between ammonia escape and the difference in restrictions between the branches. The x-axis can represent the difference in restrictions between the branches (e.g., the tailpipe pressure drop Δ at a certain rated flow rate), and the y-axis can represent the difference in ammonia escape between the branches (e.g., the Δ between the branches). A higher value in the y-axis indicates more ammonia escape from at least one of the branches. Additionally, in Figure 3 such a system described in, due to an increase in the difference in restrictions, the system may experience an increase in reductant escape. For example, the difference in restrictions may cause some systems to overestimate the mass flow through at least one branch. Therefore, when the estimated mass flow does not represent the actual mass flow, the system may increase the dosing rate of the reductant, resulting in over-dosing of the reductant. In some other cases, the difference in restrictions may cause the system to underestimate the mass flow across at least one branch. In this case, the system may under-dose the branch, leading to an increase in NO x escape. Therefore, the system and method configure the controller 100 to detect an imbalance caused by restrictions in at least one of the branches and diagnose the imbalance to at least minimize reductant escape or NO x escape. As shown, an increase in ammonia escape is proportional to an increase in the difference in restrictions (e.g., an increase in the tailpipe pressure drop Δ between the branches).

[0105] Reference Figure 5, depicts an example graph 500 of collected data, which includes pressure characteristics or measurements when the restriction is upstream of the catalytic converter outlet in the second branch 22B (e.g., upstream of the pressure sensor 16 at the outlet of the catalytic converter component). The y-axis represents the pressure reading relative to the x-axis (e.g., the Δ pressure reading across a certain catalytic converter component), and the x-axis represents the total mass flow rate from the engine 20 (e.g., referred to as the exhaust mass flow rate). The mass flow rate is measured in actual cubic meters per second (ACMS). In this case, the restriction can be caused by the inlet pipe leading to the aftertreatment system, such as misalignment or blockage, or inside the catalytic converter component (e.g., the difference in soot loading between the two branches). As Figure 5 shown, due to this restriction, the system may experience an imbalance in mass flow rate. For example, the data point marked as 0% in the legend (e.g., the baseline data point) represents the pressure measurement of a balanced system. A balanced system refers to a system with a 50-50 flow distribution on the branches of the aftertreatment system 22. In the case where there is a restriction upstream of the pressure sensor 16, the data points regarding the branch with a higher mass flow rate (e.g., marked as 60%) are shown to be higher than the balanced data point, indicating a relatively higher pressure reading. Additionally, the data points regarding the branch with a lower mass flow rate (e.g., marked as "low flow branch") are shown to be lower than the balanced data point, indicating a relatively lower pressure reading. In this case, at the 60% inlet valve position, the flow distribution is 55-45 (or 55% and 45% respectively), where 55% (e.g., marked in the legend) of the exhaust mass flow rate passes through the high flow branch, and 45% of the exhaust mass flow rate passes through the low flow branch. Therefore, this characteristic of the high flow branch and the low flow branch indicates that the restriction is upstream of the pressure sensor 16. When there is a restriction upstream of the pressure sensor location (e.g., measuring the pressure at the outlet of the DPF component 40), the sum of the mass flow rates of each branch is equal to or approximately equal to the engine exhaust gas mass flow rate.

[0106] The valve position can be adjusted to simulate the asymmetry of different tailpipes or inlet pipes in the test unit (e.g., adjusting, managing, or controlling the symmetry between branches). For example, the valve position can be used to avoid manufacturing different tailpipes for each branch or finding space for a standard test unit size to accommodate different tailpipe requirements. In the example discussed above, a 60% inlet valve position corresponds to holding the inlet valve (valve 2) of the second branch (branch 2) at a 60% closed position while all other valves are open (0% closed position), resulting in a 55% flow rate in the first branch (branch 1) and a 45% flow rate in branch 2. In some cases, a 90% outlet valve position corresponds to holding the outlet valve (valve 4) of branch 2 at a 90% closed position while all other valves are open (0% closed position), resulting in a 60% flow rate via branch 1 and a 40% flow rate via branch 2. For example, a 60% inlet valve position can correspond to a certain length of additional pipe or pipe bend on the inlet side of branch 2 compared to branch 1. Similarly, 90% on the outlet side can correspond to a certain additional length of pipe or pipe bend on the outlet side of branch 2 compared to the outlet of branch 1, thus resulting in a restriction or difference in the flow rate between the first and second branches.

[0107] Reference Figure 6 , depicts an example graph 600 of collected data, which includes pressure characteristics or measurements when the restriction is downstream of the catalyst outlet of the second branch 22B (e.g., downstream of the pressure sensor 16 at the outlet of the catalyst component). As shown, similar to Figure 5 , baseline data points are shown in the graph (e.g., labeled 0% in the legend), indicating the pressure characteristics of the balanced system. The x-axis and y-axis of graph 600 are similar to the x-axis and y-axis of graph 500. In some cases, the restriction is downstream of the pressure sensor 16 of the second branch 22B. As shown, the pressure measurements of the first branch 22A and the second branch 22B (e.g., having a 90% outlet valve position representing a 60 - 40 flow rate distribution (labeled in the legend)) are higher than the baseline data points, indicating that the restriction is downstream of the pressure sensor 16. Thus, for a restriction downstream of the pressure sensor 16, the pressure characteristics collected by the pressure sensor 16 are higher than the baseline data for both the high-flow and low-flow branches (e.g., the reverse pressure characteristics of the low branch as shown in part 602).

[0108] In the case where there is a restriction upstream of the pressure sensor 16 used to estimate the mass flow rate, the system may not require a correction / adjustment factor to correct / adjust the estimated mass flow rate. However, in the case where there is a restriction downstream of the pressure sensor 16, the system is configured to identify variables that may contribute to the downstream restriction to resolve or diagnose unbalanced mass flow rates (e.g., overestimated and / or underestimated mass flow rates).

[0109] ReferenceFigure 7 , depicts an example overview process flow diagram of a mass flow distribution management process 700 in a multi-branch post-processing system using pressure information. Figure 7 The processes, operations, or steps can be performed, operated, or executed by components of the system 10, a data processing system, a cloud computing environment, or any other computing device described herein Figures 1-6 (e.g., the controller 100, the I / O device 120, the post-processing system 22, sensors, etc.). For example, additional or alternative operations of the process 700 can be performed by one or more circuits of the controller 100. Additionally or alternatively, some operations of the process 700 can be performed by a remote device (such as a remote data processing system). Some operations of the process 700 can involve the controller 100 receiving data from components of the post-processing system 22 (such as one or more sensors) and forwarding the data to a remote device for processing, or vice versa.

[0110] At step 702, the controller 100 (e.g., the flow circuit 108) is configured to estimate a first mass flow rate of the exhaust gas in the first branch 22A. The first mass flow rate of the exhaust gas can be estimated based on: pressure data from the pressure sensor 16 in the first branch 22A, such as the catalyst outlet pressure or the pressure difference across a catalyst component (e.g., the first DPF component).

[0111] At step 704, the controller 100 (e.g., the flow circuit 108) is configured to estimate a second mass flow rate of the exhaust gas in the second branch 22B. The second mass flow rate of the exhaust gas can be estimated based on: pressure data from the pressure sensor 16 in the second branch 22B, such as the catalyst outlet pressure or the pressure difference across a catalyst component (e.g., the second DPF component).

[0112] At step 706, the controller 100 (e.g., the flow circuit 108) is configured to calculate an estimated total mass flow rate based on the estimated first mass flow rate and the estimated second mass flow rate. The controller 100 can calculate the estimated total mass flow rate by summing the estimated first mass flow rate and the estimated second mass flow rate. In various embodiments, the controller 100 is configured to use other methods, operations, or techniques to calculate the estimated total mass flow rate.

[0113] In step 708, the controller 100 (e.g., the flow circuit 108) determines that the estimated total mass flow rate is greater than the engine exhaust mass flow rate. The engine exhaust mass flow rate corresponds to the total mass flow rate at the outlet of the engine 20. In response to determining that the estimated total mass flow rate is greater than the engine exhaust mass flow rate, the controller 100 (e.g., the correction circuit 109) is configured to calculate a correction factor for balancing the estimated first mass flow rate and the estimated second mass flow rate. Balancing the estimated first mass flow rate and the estimated second mass flow rate may refer to correcting at least one of the mass flow rates such that the sum of the estimated mass flow rates is at or about the engine exhaust mass flow rate (e.g., within a deviation of 5%, 3%, etc. of the engine exhaust mass flow rate), or within a predetermined threshold / range of the engine exhaust mass flow rate. Having the estimated total mass flow rate at or about the engine exhaust indicates that the estimated mass flow rate of each branch is accurate.

[0114] In step 710, the controller 100 (e.g., the flow circuit 108 or the correction circuit 109) is configured to use the correction factor to estimate the corrected first mass flow rate of the exhaust gas in the first branch 22A and the corrected second mass flow rate of the exhaust gas in the second branch 22B. The controller 100 is configured to apply the correction factor to the estimated mass flow rate of each branch to increase or decrease the estimated mass flow rate. In some cases, the correction factor indicates the proportion of the engine exhaust mass flow rate received by each branch. In such a case, the controller 100 is configured to apply the correction factor to the engine exhaust mass flow rate to estimate the corrected first mass flow rate and the corrected second mass flow rate based on the proportion.

[0115] In step 712, the controller 100 (e.g., the adjustment circuit 111) is configured to adjust at least one of the reductant dosing, hydrocarbon dosing, or soot load estimation based on the corrected first mass flow rate and the corrected second mass flow rate. An increase from the estimated mass flow rate to the corrected mass flow rate may, due to an increase in exhaust by-products in the branch, result in at least one of the following: an increase in reductant dosing, advancing the timing or frequency of hydrocarbon dosing, or increasing the soot load estimation. A decrease from the estimated mass flow rate to the corrected mass flow rate may, due to a decrease in exhaust by-products in the branch, result in at least one of the following: a decrease in reductant dosing, delaying the timing or frequency of hydrocarbon dosing, or decreasing the soot load estimation. In various arrangements, Figure 8 The operation, techniques, or features of process 700 are described in further detail.

[0116] Reference Figure 8 , depicts an example process flow diagram of an example proportional correction process 800 for performing Figure 7 in a multi-branch aftertreatment system using pressure information.Figure 8 The processes, operations, or steps can be completed, operated, or performed by components of system 10, a data processing system, a cloud computing environment, or any other computing device described herein in combination Figures 1-7 with (e.g., controller 100, I / O device 120, post-processing system 22, sensors, etc.). For example, additional or alternative operations of process 800 can be performed by one or more circuits of controller 100. Additionally or alternatively, some operations of process 800 can be performed by a remote device (such as a remote data processing system). Some operations of process 800 can involve controller 100 receiving data from components of post-processing system 22 (such as one or more sensors) and forwarding the data to a remote device for processing, or vice versa.

[0117] Process 800 begins at step 802. For example, at step 802, controller 100 can receive a command or indication to initiate operations for monitoring and diagnosing unbalanced flow distribution within system 10. Controller 100 receives the command via communication interface 104 from I / O device 120 or other removal device. In some cases, controller 100 initiates process 800 in response to receiving an indication of a restriction within the system (such as a restriction downstream of pressure sensor 16 for estimating mass flow) from (e.g., another processing device).

[0118] At step 804, controller 100 (e.g., flow circuit 108) estimates or calculates the mass flow of each branch (e.g., first branch 22A and / or second branch 22B) of post-processing system 22. Each branch includes a corresponding one or more components of post-processing system 22. For each branch, flow circuit 108 estimates the mass flow based on pressure information associated with a catalytic component (e.g., DPF component 40 or other catalytic component). The pressure information includes at least one of the following: catalytic output pressure (e.g., DPF output pressure) or Δ pressure (e.g., pressure difference / differential across DPF component 40 or the difference between the pressure at the inlet and the outlet of DPF component 40). Flow circuit 108 can use the following equation / formula to estimate the mass flow based on pressure data:

[0119]

[0120] A = the open frontal area of SCR catalytic component 50 or subsequent catalytic component from DPF component 40

[0121] k = flow coefficient

[0122] ρ = density

[0123] Δ = Δ (delta)

[0124] P = Pressure.

[0125] In some cases, the flow circuit 108 is configured to calculate the mass flow rate using the following simplified model:

[0126]

[0127] ΔP = DPF OutP - AmbP

[0128] k = Flow coefficient, which can be implemented as a look-up table

[0129] DPF = DPF component 40 (e.g., other catalytic component can be used)

[0130] OutP = Pressure at the outlet of the catalytic component

[0131] AmbP = Ambient pressure or pressure around the catalytic component.

[0132] The flow circuit 108 calculates the density (rho) as follows:

[0133]

[0134] P 床层 = Bed pressure of the catalytic component

[0135] R = Ideal gas constant

[0136] T 床层 = Bed temperature of the catalytic component.

[0137] To make this iteration converge to its true value, the flow circuit 108 uses a transformation technique (e.g., Newton - Raphson method) to calculate the estimated mass flow rate of the corresponding branch:

[0138]

[0139] where i = 0, 1, 2, 3

[0140]

[0141] The acceptable or desired range of flow accuracy (e.g., the difference in mass flow between one branch and another) is higher or lower than the minimum mass flow (e.g., the total engine flow of 24 kg / min, 18 kg / min, etc.) by + / - 2% or + / - 3%. In response to a decrease in the accuracy of estimating the flow distribution between branches due to, for example, noise or restrictions downstream of one or more sensors 16, the flow circuit 108 is configured to estimate a correction factor using an equation.

[0142] The flow circuit 108 uses the estimated mass flow to identify the mass flow in one branch relative to the mass flow in another branch, thereby normalizing the modeling error in the mass flow calculation. Based on the above equation, the flow current 108 can estimate the mass flow in each branch (e.g., the first mass flow of the exhaust gas in the first branch 22A and the second mass flow of the exhaust gas in the second branch 22B) based on at least one of the catalytic converter output pressure or the pressure difference across the catalytic converter member. In some embodiments, the flow circuit 108 is configured to use other equations to estimate the mass flow in the system.

[0143] The flow circuit 108 calculates (e.g., estimates) the total mass flow based on the estimated mass flow of the branches. For simplicity, the estimated total mass flow corresponds to the sum of the estimated mass flows at a certain moment or over a time window. In some cases, when the engine exhaust mass flow (e.g., volumetric flow) is higher than a threshold (e.g., 0.3 ACMS, 0.4 ACMS, 0.5 ACMS, etc.), or when the pressure at the outlet of the engine 20 is higher than a threshold (e.g., 4 kPa, 6 kPa, 8 kPa, etc.), the flow circuit 108 calculates the estimated total mass flow. A higher engine exhaust mass flow can reflect a higher Δ between the estimated total mass flow and the engine exhaust mass flow, which can be used to identify inaccuracies in the estimated mass flow based on pressure information. The engine exhaust mass flow refers to the mass flow measured at the outlet pipe of the engine 20 upstream of the branch.

[0144] At step 806, the controller 100 (e.g., the flow circuit 108) determines whether the total mass flow rate of the branch is greater than or higher than the engine exhaust mass flow rate. In some cases, the controller 100 determines whether the total mass flow rate of the branch is at least a predetermined value (e.g., a percentage or a predetermined ratio) greater than the engine exhaust mass flow rate. If the estimated total mass flow rate is higher than the engine exhaust mass flow rate, the process 800 proceeds to step 810. The estimated total mass flow rate being greater than the engine exhaust mass flow rate reflects an unbalanced flow distribution with a restriction downstream of the pressure sensor 16 used to estimate the mass flow rate. In such a case, the estimated mass flow rate of at least one of the branches in the branch is inaccurate. In other cases, if the estimated total mass flow rate is equal to or lower than the engine exhaust mass flow rate, the process 800 proceeds to step 808.

[0145] In the case where there is a mass flow leak or escape from certain joints of the aftertreatment system 22, thereby reducing the total mass flow rate, the total mass flow rate can be lower than the engine exhaust mass flow rate. In some embodiments, if the total mass flow rate is below a predefined threshold (e.g., less than 80%, 90%, etc. of the expected total mass flow rate), the controller 100 can initiate a silent fault to notify the operator via the operator I / O device 102 or transmit a signal to a service technician (e.g., notify the service technician) to check for leaks during the next maintenance event of the system 10.

[0146] At step 808, the controller 100 (e.g., the correction circuit 109) determines that no correction factor is required for the flow distribution based on the estimated total mass flow rate being equal to or lower than the engine exhaust mass flow rate. The estimated total mass flow rate being equal to or lower than the engine exhaust mass flow rate reflects a balanced flow distribution or an unbalanced flow distribution where the restriction is upstream of the pressure sensor 16 used to estimate the mass flow rate. Thus, even if the flow distribution is unbalanced, the estimated mass flow rate of each branch is accurately estimated, and the controller 100 (e.g., the adjustment circuit 111) can adjust the reductant dosing rate, control hydrocarbon injection, and / or soot loading estimation accordingly.

[0147] At step 810, the controller 100 (e.g., the adjustment circuit 111) determines whether the SCR catalyst member 50 has been regenerated (e.g., whether regeneration has been performed or is in progress for the SCR catalyst member 50). If the regeneration is not yet complete, then at step 812, the controller 100 (e.g., the adjustment circuit 111) triggers or continues the regeneration of the SCR catalyst member 50. The regeneration process removes deposits or catalyst deactivation compounds (e.g., potential limitations) and restores the SCR catalyst member 50 to a predefined active level. The controller 100 activates the regeneration process because an imbalance may be caused by deposits in the SCR catalyst member 50 of the first branch 22A or the second branch 22B.

[0148] In various embodiments, in response to determining that the estimated total mass flow rate is greater than the engine exhaust mass flow rate and before calculating the correction factor, the controller 100 initiates hydrocarbon rationing to regenerate at least one of the first SCR catalyst member of the first branch 22A and / or the second SCR catalyst member of the second branch 22B. In some cases, the controller 100 receives an indication of whether each SCR catalyst member 50 has been regenerated. Accordingly, the controller 100 initiates hydrocarbon rationing to regenerate at least one of the SCR catalyst members 50 that has not yet been or is not in the regeneration process. In some cases, the controller 100 initiates hydrocarbon rationing as part of the start of process 800, such as initiating hydrocarbon rationing at step 802. If the regeneration is complete, then process 800 proceeds to step 814.

[0149] At step 814, similar to step 806, the controller 100 (e.g., the flow circuit 108) determines whether the estimated total mass flow rate is higher than the engine exhaust mass flow rate after performing the regeneration. For example, after regenerating at least one SCR catalyst member 50 in the respective branch of the aftertreatment system 22, the controller 100 estimates a third mass flow rate of the exhaust gas in the first branch 22A and a fourth mass flow rate of the exhaust gas in the second branch 22B (e.g., calculated similar to step 804). Using the third mass flow rate and the fourth mass flow rate, the controller 100 calculates (e.g., a second) estimated total mass flow rate for comparison with the engine exhaust mass flow rate. The estimated total mass flow rate may be similar to the total mass flow rate above. If the estimated total mass flow rate is still higher than the engine exhaust mass flow rate, then process 800 proceeds to step 818.

[0150] In other cases, if the estimated total mass flow rate is equal to or lower than the engine exhaust mass flow rate, process 800 proceeds to step 816. Similar to step 808, at step 816, the controller 100 may not apply a correction factor to the estimated flow distribution because the regeneration event resolves the imbalance between the branches (e.g., the imbalance caused by the SCR catalyst component 50), such that the estimated total mass flow rate is, for example, equal to the engine exhaust mass flow rate. As described herein, since the restriction occurs downstream of the pressure sensor 16, the controller 100 (e.g., the correction circuit 109) is configured to calculate a correction factor for balancing or correcting the estimated first mass flow rate and the estimated second mass flow rate calculated based on the pressure information.

[0151] At step 818, the controller 100 determines whether the system (e.g., the aftertreatment system 22 or at least one of the branches of the aftertreatment system 22 or components of the branches) is newly installed. The controller 100 determines whether the system is newly installed in response to the estimated total mass flow rate being higher than the engine exhaust mass flow rate (associated with at least one of steps 706 or 714). In some cases, the controller 100 determines whether the system is newly installed at the start of process 800 (at step 802). In some other cases, the controller 100 determines whether the system is newly installed after the regeneration event is completed at step 810. If the system is newly installed, process 800 proceeds to step 820. Considering that one or more components of the aftertreatment system 22 are also newly installed, a system with a newly installed system (e.g., a system with a relatively low engine operating hour count such as less than 50 hours, 100 hours, etc.) may indicate that the restriction is caused by the original equipment manufacturer (OEM) piping or not caused by soot load accumulation or SCR deposits. In such cases, the newly installed system with a certain restriction is due to piping differences in the system. A system that is no longer considered a new system (e.g., the engine operating hour count is greater than or equal to a predefined threshold) may have different restrictions between the branches due to, for example, ash or soot or deposit formation accumulated in certain components of the aftertreatment system 22, such as soot accumulation in the DPF component 40 of one branch or deposit formation in the SCR catalyst component 50 compared to another branch.

[0152] At step 820, the controller 100 (e.g., the correction circuit 109) calculates a correction factor in response to determining that the first branch 22A or the second branch 22B is newly installed. The controller 100 calculates the correction factor for the newly installed system by performing a proportional correction on the estimated mass flow rate based on the ACMS value calculated from the catalyst outlet pressure. To perform the proportional correction, process 800 proceeds to step 828.

[0153] At step 828, the controller 100 (e.g., the correction circuit 109) determines the pressure difference across the first SCR catalyst member in the first branch 22A and the second SCR catalyst member in the second branch 22B. The pressure difference represents the pressure drop across the catalyst member (e.g., the DPF member 40). The controller 100 determines the pressure difference based on the difference between a first pressure value at the inlet or upstream of the catalyst member and a second pressure value at the outlet or downstream of the catalyst member. The controller 100 determines a first pressure difference in the first branch 22A and a second pressure difference in the second branch 22B.

[0154] At step 830, the controller 100 (e.g., the correction circuit 109) calculates a correction factor based on the ratio between the two pressure differences. The ratio between the pressure differences represents the flow distribution between the branches. For example, based on the ratio between the two branches using the pressure differences, the controller 100 can determine which of the branches is the low-flow branch (e.g., the branch with a relatively lower mass flow rate) and which is the high-flow branch (e.g., the branch with a relatively higher mass flow rate). The branch corresponding to the higher pressure difference may represent the high-flow branch, and the branch corresponding to the lower pressure difference may represent the low-flow branch. For example, in the case where there is a relatively higher restriction downstream of the pressure sensor (such as in the first branch compared to the second branch), the pressure sensor in the first branch can measure a higher back pressure caused by the higher restriction downstream of the pressure sensor in the first branch compared to the second branch. In another example, where there is a relatively higher restriction upstream of the pressure sensor in one branch compared to another branch, such as in the first branch compared to the second branch (e.g., in this case there is no downstream pressure difference), when there is a higher mass flow rate in the first branch, the pressure sensor can sense a higher pressure. However, because there are relatively more upstream restrictions in the first branch than in the second branch, the mass flow rate in the first branch is lower than that in the second branch, and the pressure sensor can sense a lower pressure on the first branch.

[0155] In various embodiments, the correction factor is a multiplier based on a ratio between pressure differences (e.g., 55 - 45, 60 - 40, 65 - 45, etc.). The controller 100 is configured to apply the correction factor to the engine exhaust mass flow rate. Using the ratio of 60 - 40 (or mass flow rate distribution) as an example, the controller 100 is configured to estimate the corrected mass flow rate of the low - flow branch by applying the correction factor (e.g., the lower ratio, e.g., 40% in this case) to the engine exhaust mass flow rate (e.g., 40% of the engine exhaust mass flow rate). In some cases, the controller 100 is configured to estimate the corrected mass flow rate of the high - flow branch by applying the correction factor (e.g., the higher ratio, such as 60% in this case) to the engine exhaust mass flow rate (e.g., 60% of the engine exhaust mass flow rate). Thus, the controller 100 can estimate the corrected mass flow rate of each branch based on the ratio between pressure differences. For example, it can be combined at least with Figure 8 The operation of calculating and applying the correction factor based on the ratio between pressure differences is described in more detail.

[0156] Returning to step 818, the controller 100 may receive an indication that neither the first branch 22A nor the second branch 22B nor any component therein is newly installed or determine that neither the first branch 22A nor the second branch 22B nor any component therein is newly installed. If the system is not newly installed, the process 800 proceeds to step 822.

[0157] In step 822, the controller 100 (e.g., the flow circuit 108) determines whether a soot - load flow re - balance has occurred or is true. Soot - load flow re - balance refers to the accumulation of soot over time in the catalyst components (e.g., the first catalyst component in the first branch 22A and the second catalyst component in the second branch 22B), which causes the mass flow rate distribution to be balanced. For example, when the soot load is low, there may be an unbalanced flow rate distribution in the system. Since soot accumulates faster in the high - flow branch (e.g., more soot crosses into the high - flow branch) and slower in the low - flow branch (e.g., less soot crosses into the low - flow branch), the high - flow branch accumulates more soot load compared to the low - flow branch. Over time, the soot load causes the restriction in the high - flow branch to be comparable to the existing restriction in the low - flow branch, thus balancing the flow rate distribution between the branches of the after - treatment system 22. Therefore, the controller 100 is configured to monitor the flow rate distribution and the soot load over time to determine whether the flow rate distribution has been balanced due to soot - load accumulation.

[0158] After determining in step 818 that the system is not newly installed, the controller 100 determines whether a soot load flow rebalance has occurred. In some cases, the controller 100 determines whether a soot load flow rebalance has occurred after determining that the estimated total mass flow is higher than the engine exhaust mass flow (associated with at least one of steps 706 or 714). In some other cases, for example, the controller 100 determines whether a soot load flow rebalance has occurred after completing a regeneration event in step 810.

[0159] If the controller 100 determines that the flow distribution has rebalanced due to soot load accumulation, the process 800 proceeds to step 824. In other cases, the process 800 proceeds to step 826. In either case, the controller 100 is configured to calculate a correction factor based on the estimated soot load flow (e.g., the mass flow relative to the soot load).

[0160] In step 824, the controller 100 (e.g., the correction circuit 109) calculates a correction factor based on the engine exhaust mass flow of each branch (e.g., half of the engine exhaust mass flow) and the virtual value of the corresponding branch. In this case, the correction factor is a multiplier that increases or decreases the estimated mass flow when applied to at least one of the estimated mass flows to estimate the corrected mass flow. The following formula can be used to determine the correction factor:

[0161]

[0162] For example, half of the engine exhaust mass flow represents the desired mass flow for each branch. The virtual value represents the estimated mass flow for the corresponding branch based on at least one of the differential pressure or the catalytic converter output pressure information. The controller 100 calculates the virtual value based on the estimated total mass flow and the flow distribution across the branches of the aftertreatment system 22. For example, if the engine exhaust mass flow is 50 kg / min, the controller 100 determines that each branch has a mass flow of 25 kg / min for a 50 / 50 flow distribution. If the estimated total mass flow is 55 kg / min, with the first branch at 30 kg / min and the second branch at 25 kg / min, the controller 100 calculates a correction factor of 25 / 30 = 0.833 for the first branch and 25 / 25 = 1 for the second branch. In another example, if the first branch corresponds to a mass flow of 32 kg / min and the second branch corresponds to a mass flow of 23 kg / min, the controller 100 calculates a correction factor of 25 / 32 = 0.78 for the first branch and 25 / 23 = 1.08 for the second branch.

[0163] Based on the above technology, the controller 100 is configured to calculate or estimate a first virtual mass flow rate (e.g., a first virtual value) of the exhaust gas in the first branch 22A based on a first pressure difference across the first DPF component in the first branch 22A. Additionally, the controller 100 is configured to estimate a second virtual mass flow rate (e.g., a second virtual value) of the exhaust gas in the second branch 22B based on a second pressure difference across the second DPF component in the second branch 22B. Using the respective pressure differences of the respective branches, the controller 100 is configured to calculate a correction factor (e.g., via the formula provided above) based on at least one of the estimated first virtual mass flow rate or the estimated second virtual mass flow rate and the engine exhaust mass flow rate.

[0164] In step 826, the controller 100 (e.g., the correction circuit 109 and / or the modeling circuit 110) is configured to calculate a correction factor based on a matching model in the case where the soot loading does not rebalance the flow. The process 800 proceeds to step 832 to perform the correction factor calculation based on the matching model.

[0165] In step 832, the controller 100 (e.g., the modeling circuit 110) determines pressure differences (e.g., a first pressure difference and a second pressure difference) across the respective particulate filters (e.g., the first DPF component and the second DPF component) over a time window. The time window includes various time intervals representing the frequency for determining the pressure differences. Examples of the time window and the time intervals include a 1-minute time window with a 1-second time interval, a 5-minute time window with a 5-second time interval, etc.

[0166] In step 834, in each time interval, the controller 100 (e.g., the modeling circuit 110) compares the pressure differences with a set of calibration tables. The set of calibration tables includes a plurality of predetermined pressure differences representing different flow distributions of the engine exhaust mass flow rate. The predetermined pressure differences can be expressed as a ratio of the pressure differences between the branches, such as 50-50 (for a balanced system), 55-45, 60-40, 65-45, 70-30, etc. Each calibration table in the set of calibration tables is assigned a corresponding bucket for scoring the comparison.

[0167] In step 836, in each time interval within the time window, the controller 100 (e.g., the modeling circuit 110) is configured to increase the score of at least one calibration table in the set of calibration tables in response to the calculated pressure differences (e.g., the first pressure difference and the second pressure difference) or the ratio of the pressure differences being equivalent or matching to the predefined pressure differences or predefined ratios of such calibration tables. The controller 100 repeats this process for the remainder of the time window, and the process 800 proceeds to step 838.

[0168] At step 838, at the end of the time window, the controller 100 (e.g., the calibration circuit 109) calculates a correction factor for at least one branch of the aftertreatment system 22 based on the selected flow distribution corresponding to the highest-scoring calibration table in the set. For example, based on the comparison and at the end of the time window, the controller 100 collects the scores associated with each calibration table in the set.

[0169] By comparing the scores of each calibration table to each other, the controller 100 is configured to select the calibration table with the highest score (e.g., bin). Additionally, the controller 100 selects the flow distribution corresponding to the highest-scoring calibration table and uses the selected flow distribution to calculate the correction factor. Similar to proportional correction, the controller 100 can apply the flow distribution to the engine exhaust mass flow to estimate the corrected mass flow of at least one of the branches (e.g., the high-flow branch and / or the low-flow branch). In some arrangements, for example, the controller 100 clears the score or bin of the calibration table after selecting the highest-scoring calibration table, selecting the flow distribution, or calculating the correction factor. This can be combined at least Figure 10 The operation for matching the model-based correction factor is described in further detail.

[0170] As described herein, the controller 100 (e.g., the calibration circuit 109) is configured to apply the correction factor for estimating the corrected mass flow. Subsequently, the controller 100 (e.g., the adjustment circuit 111) is configured to adjust at least one of the reductant dosing, hydrocarbon dosing, or soot load estimation based on the corrected first mass flow and the corrected second mass flow. For example, the controller 100 (e.g., the adjustment circuit 111) can reduce the reductant dosing of a branch with an overestimated mass flow (e.g., from the estimated mass flow to the corrected mass flow). In some cases, the controller 100 can increase the reductant dosing of a branch with an underestimated mass flow (e.g., from the estimated mass flow to the corrected mass flow).

[0171] In various arrangements, the controller 100 (e.g., the adjustment circuit 111) is configured to adjust the hydrocarbon dosing (e.g., frequency or timing) based on the corrected mass flow. For example, an overestimated mass flow may result in an early or premature regeneration event (e.g., a hydrocarbon dosing event). By applying the correction factor to the estimated mass flow, the overestimation is corrected, and the controller 100 can initiate a regeneration event (e.g., relatively less frequently or at a later time compared to when the mass flow was overestimated) based on the corrected mass flow of the corresponding branch. Similarly, after correcting an underestimated mass flow, the controller 100 can advance the timing or increase the frequency of the regeneration event for the associated branch with the underestimated mass flow.

[0172] In addition, the controller 100 (e.g., the adjustment circuit 111) corrects the soot load estimation based on the corrected mass flow rate. For a branch with an overestimated mass flow rate, the controller 100 can reduce the soot load estimation proportionally to the decrease in the branch from the estimated mass flow rate to the corrected mass flow rate. For a branch with an underestimated mass flow rate, the controller 100 can increase the soot load estimation proportionally to the increase in the branch from the estimated mass flow rate to the corrected mass flow rate. Although the examples herein include adjustments to reductant dosing, hydrocarbon dosing, and soot load estimation, the controller 100 is configured to adjust or control other components of the system 10 based on the corrected mass flow rate in at least one of the branches.

[0173] Figure 9 Graphs 902 - 912 are shown, which depict example operations associated with Figure 8 the Δ-pressure based correction process, such as for a newly installed system. Each graph represents steps for performing proportional correction, such as those described in connection with Figure 8 at least steps 820, 828, and 830. Referring to graph 902, the controller 100 (e.g., the flow circuit 108) receives catalyst outlet pressure data from the pressure sensors 16 in each of the branches including the low flow branch and the high flow branch. As shown, the catalyst outlet pressure readings for both the low flow branch (e.g., part 914) and the high flow branch (e.g., in the legend labeled 65 - 35) are higher than the data point representing balanced flow distribution (e.g., in the legend labeled 50 - 50).

[0174] In graph 904, the controller 100 estimates the mass flow rate of each branch based on the catalyst outlet pressure data of graph 902. As shown, when using the catalyst outlet pressure data for mass flow rate estimation, the exhaust mass flow rate of the second branch 22B (e.g., the low flow branch, labeled "65 - 35L2" in the legend) is overestimated. Part 916 includes the estimated mass flow rate of the low flow branch (e.g., in this case, the second branch 22B), which is higher than the baseline mass flow rate (e.g., the 50 - 50 data point).

[0175] Subsequently, in graph 906, the controller 100 estimates the total mass flow rate (e.g., by adding the respective mass flow rates) based on the first branch 22A and the second branch 22B. The controller 100 determines that the estimated total mass flow rate is greater than the engine exhaust mass flow rate, as shown in part 918. In this example, the engine exhaust mass flow rate is the baseline data point labeled, for example, "50 - 50". Since the estimated total mass flow rate is greater than the engine exhaust mass flow rate and under the indication that the system is newly installed, the controller 100 determines to perform proportional correction to correct the mass flow rate estimation of at least one of the branches (e.g., the low flow branch).

[0176] In graph 908, controller 100 receives an indication that the catalytic component has been cleaned (e.g., assuming the system is newly installed). Regarding the cleaned catalytic component, controller 100 is configured to determine which of the branches is the low-flow branch or the high-flow branch based on the Δ-pressure information across the catalytic component (e.g., DPF Δ-pressure (dp)). For example, controller 100 receives the Δ-pressure information across the catalytic component of the corresponding branch. As shown, controller 100 identifies the high-flow branch based on the catalytic Δ-pressure (e.g., labeled "65 - 35") being higher than the baseline data point. Additionally, controller 100 identifies the low-flow branch based on the catalytic Δ-pressure (e.g., in section 920) being lower than the baseline data point. Thus, controller 100 is configured to use the Δ-pressure across the catalytic component to identify the low-flow branch and the high-flow branch.

[0177] Controller 100 calculates the ratio between the Δ-pressures of the high-flow branch and the low-flow branch. The ratio between the Δ-pressures can be used as part of a correction factor. For example, controller 100 applies this ratio to the engine exhaust mass flow. In this case, the ratio is 65% for the high-flow branch and 35% for the low-flow branch, based on the estimated Δ-pressure of the corresponding catalytic component. Controller 100 calculates a first corrected mass flow for the low-flow branch corresponding to 35% of the engine exhaust mass flow and a second corrected mass flow for the high-flow branch corresponding to 65% of the engine exhaust mass flow. In some cases, controller 100 applies a ratio correction to the pressure data (e.g., catalytic converter output pressure) of at least one of the branches such that the corrected pressure data can be used to calculate the corrected mass flow.

[0178] In various embodiments, for example, controller 100 is configured to ignore or skip the estimation of the corrected mass flow for the high-flow branch because the pressure data of the second branch 22B may not be affected by the restrictions in the low-flow branch. For simplicity, when the high-flow branch is not affected by the restrictions, controller 100 is configured to correct the mass flow estimation of the low-flow branch without adjusting the estimated mass flow of the high-flow branch. In other cases, controller 100 is configured to adjust the estimated mass flow of both branches.

[0179] In graph 910, the controller 100 applies a correction factor to the estimated mass flow rate of the low flow branch. In some cases, applying the correction factor can include using the corrected mass flow rate calculated for the corresponding branch. As shown in portion 922, the controller 100 applies the correction factor to the low flow branch to correct / diagnose an overestimation of the mass flow rate of the low flow branch. In some cases, the controller 100 also applies the corresponding correction factor to the high flow branch to adjust the estimated mass flow rate of the second branch 22B. Compared to graph 904, the corrected mass flow rate of the low flow branch is lower than the baseline data point.

[0180] In graph 912, the controller 100 aggregates or sums the corrected mass flow rates to determine the corrected total mass flow rate. As shown in portion 924, compared to graph 906, the data points representing the corrected total mass flow rate are substantially the same as the data points of the engine exhaust mass flow rate. Thus, the mass flow rate across the branches represents the engine exhaust mass flow rate entering the aftertreatment system 22.

[0181] Now referring to Figure 10 , a block diagram of an example matching model 1000 associated with at least Figure 8 step 826 is depicted. The controller 100 (e.g., the correction circuit 109 and / or the modeling circuit 110) is configured to use the matching model 1000 to calculate the correction factor when at least the system is not newly installed and the flow distribution has not been rebalanced due to soot loading. The process of the matching model 1000 can be described in conjunction with Figure 8 step 826 and steps 832 - 838. In various arrangements, the matching model 1000 can be executed continuously or periodically (e.g., at predefined time intervals or based on certain operating events of the engine 20, such as engine ignition, generation of exhaust by-products, etc.).

[0182] The matching model 1000 includes an input block 1002 and a flow distribution calculation block 1004. The input block 1002 includes a process for receiving and aggregating input data. The input data can be used in the flow distribution calculation block 1004, which includes a process for calculating the flow distribution of the mass flow rate between the branches. As described herein in step 1018, the calculated flow distribution can be monitored within a predefined time window (e.g., window-based monitoring logic).

[0183] At step 1006, the controller 100 receives or determines the (e.g., total) engine exhaust mass flow rate from the engine 20. The controller 100 calculates the engine exhaust mass flow rate based on the sum of the fresh air flow rate at the engine inlet and the fuel flow rate delivered to the combustion chamber by at least one fuel injector. The fresh air flow rate corresponds to, for example, the inlet air flow rate measured by a flow sensor or measured based on the sum of the charge flow and the EGR flow rate. The charge flow is calculated using the PV = mRT equation (e.g., the ideal gas law). The EGR flow rate is calculated using the flow rate through the venturi equation. In this case, for example, there may be a charge pressure sensor and a venturi pressure sensor in the engine architecture. The engine exhaust mass flow rate reflects the desired estimated total exhaust mass flow rate distributed between the branches of the aftertreatment system 22.

[0184] At step 1008, the controller 100 applies a first-order filter to the calculated engine exhaust mass flow rate. For example, the first-order filter can be a state-update Kalman filter, as well as other types of first-order filters, such as an α-β filter or a moving average, etc. The controller 100 determines the filtered engine exhaust mass flow rate in response to applying the filter. The formula for the Kalman filter is provided as follows:

[0185]

[0186] y = the engine exhaust mass flow rate after applying the filter.

[0187] k = the incremental value as the time stamp increment, such as 1, 2, 3, 4, etc.

[0188] dt = the time difference, such as 200 ms, etc.

[0189] tau = the predefined time value, such as 2 seconds, 3 seconds, 5 seconds, etc.

[0190] At step 1010, the controller 100 determines the volumetric flow rate in cubic meters per second (ACMS) of at least one branch (e.g., for comparison with the pressure information used to estimate the mass flow rate in at least one branch). The ACMS can be calculated as follows:

[0191]

[0192] m = the mass flow rate.

[0193] R = the gas constant.

[0194] T = the Kelvin temperature.

[0195] P = gas pressure in absolute kPa based on ambient pressure and / or catalytic converter outlet pressure.

[0196] In step 1012, the controller 100 retrieves or obtains various calibration tables (e.g., sometimes referred to as models) from the memory 103 or a remote database (e.g., similar to Figure 8 the calibration table described). Each calibration table includes predefined pressure information (e.g., at least one of catalytic converter outlet pressure information or pressure differential information) corresponding to a respective flow allocation of the engine exhaust mass flow. Different pressure information corresponds to different flow allocations. For example, a first calibration table may correspond to a 60-40 flow allocation (e.g., 60% of the engine exhaust mass flow for the high flow branch and 40% of the engine exhaust mass flow for the low flow branch), a second calibration table may correspond to a 65-35 flow allocation, a third calibration table may correspond to a 70-30 flow allocation, and so on. The calibration tables may be generated or preconfigured based on fuel reading (e.g., injection) data, which may be used to calculate the mass flow at the inlet and / or outlet of the engine 20.

[0197] In various arrangements, the controller 100 selects or obtains at least one set of calibration tables based on the engine exhaust mass flow. For example, different engine exhaust mass flows result in different pressure readings (e.g., catalytic converter outlet pressure data and pressure differential data) for each branch of the aftertreatment system 22. Thus, each set of calibration tables may be configured for a respective engine exhaust mass flow. For example, the controller 100 selects at least one of the set of calibration tables based on a comparison between the calculated engine exhaust mass flow or ACMS as described in connection with step 1010 and a predefined engine exhaust mass flow associated with the respective set of calibration tables.

[0198] In step 1014, the controller 100 receives sensed / measured catalytic converter outlet pressure information for at least one branch (e.g., the first branch 22A is used as an example) under a predefined operating condition (e.g., fuel injection rate, reductant dosing rate, fresh air flow, torque request, etc.) of the engine 20 and / or the aftertreatment system 22.

[0199] In step 1016, the controller 100 applies a first-order filter to the measured catalytic converter outlet pressure of the first branch 22A (or the second branch 22B). The controller 100 uses the filtered catalytic converter outlet pressure information to compare with predefined pressure information from a calibration table (e.g., in one of a set of calibration tables based on engine exhaust mass flow). For example, the controller 100 compares the measured pressure value sensed from at least one of the pressure sensors 16 with the predefined pressure value of each calibration table. The controller 100 can identify at least one calibration table having a predefined pressure value closest to the measured pressure value. The controller 100 is configured to iterate the processes of steps 1002 and 1004 at each interval within a predefined time window, and monitor the comparison between the measured pressure value and the predefined pressure value in step 1018.

[0200] In step 1018, the controller 100 is configured to perform a window-based monitoring technique for monitoring the comparison of the measured pressure value and the model (e.g., predefined) pressure value performed within a predefined time window. Within the time window, the controller 100 tracks the number of times the corresponding pair of measured pressure values from the branches (e.g., the pressure values from the first branch 22A and the second branch 22B) match the model pressure value of at least one calibration table. In response to each match, the controller 100 increments the score or bucket corresponding to the calibration table having the model pressure value. If the measured pressure value is between the two model pressure values of different calibration tables, the controller 100 can increase the scores of both calibration tables.

[0201] At the end of the window, the controller 100 selects the model (e.g., calibration table) having the highest score (e.g., the highest number of matches). Selecting the calibration table can correspond to selecting the flow distribution corresponding to the calibration table. The controller 100 is configured to use the selected flow distribution to calculate a correction factor and correct the estimated mass flow of at least one branch. As described above, the controller 100 can apply the correction factor to the estimated mass flow, or calculate the corrected mass flow by applying the flow distribution to the engine exhaust mass flow to identify the mass flow through the high-flow branch and the low-flow branch.

[0202] Reference Figure 11 , shows a depiction related to at least Figure 8Graph 1100 of the model-based method associated with step 826. Graph 1100 shows an example scenario of measured pressure values (e.g., catalytic converter outlet pressure) and estimated / calculated mass flow rates for the first branch 22A and the second branch 22B of the post-processing system 22. Case 1 corresponds to a balanced system with a 50-50 flow distribution. Case 2 corresponds to a 57-43 flow distribution system with an inlet pipe restriction (e.g., a restriction upstream of the pressure sensor 16 for measuring pressure information). Case 3 corresponds to a 60-40 flow distribution system with an inlet pipe restriction. As shown, the (e.g., pre-calibrated) lines in Graph 1100 represent modeled pressure values for modeled mass flow rates relative to certain calibration tables. Lines 60 and 40 represent the calibration table for a 60-40 flow distribution. Lines 57 and 43 represent the calibration table for a 57-43 flow distribution. Line 50 represents the 50-50 flow distribution calibration table or baseline value.

[0203] In Case 2, the controller 100 determines that the data points of the first branch 22A and the second branch 22B are aligned with the data points of the calibration table corresponding to the 57-43 flow distribution. Thus, the controller 100 can select the 57-43 flow distribution to calculate the correction factor. In Case 3, the controller 100 can determine that the total mass flow rate is greater than the engine exhaust mass flow rate. The controller 100 is configured to correct the estimated mass flow rate of at least the low-flow branch (e.g., the second branch 22B in this case). The correction of the mass flow rate can be combined Figure 7 to describe the correction of the mass flow rate. When correcting the estimated mass flow rate, the controller 100 determines that the data points of the first branch 22A and the second branch 22B are aligned with the data points of the calibration table corresponding to the 40-60 outlet flow distribution table. In some cases, the controller 100 determines that the data points corresponding to the first branch 22A are aligned with the 60-40 inlet flow distribution table and selects that flow distribution without correcting the data points of the second branch 22B. Thus, for example, the controller 100 can select the 60-40 flow distribution to calculate the correction factor.

[0204] Refer to Figure 12, shows a graph 1200 depicting a model-based method for tailpipe restriction. Similar to graph 1200, three cases are provided, including case 1 for a 50-50 flow distribution, case 2 for a 57-43 flow distribution, and case 3 for a 60-40 flow distribution. In this case, the imbalances in the 57-43 and 60-40 flow distributions are caused by the tailpipe restriction (e.g., a restriction downstream of pressure sensor 16 used to estimate mass flow). As shown, the pre-calibrated line for the tailpipe restriction is different from the line for the inlet pipe restriction because the location of the restriction affects the pressure readings and mass flow estimates. In case 2, controller 100 determines that the data points for the first branch 22A align with the calibration table corresponding to the 57-43 flow distribution (e.g., a comparison between the measured values and the modeled values). Controller 100 selects the 57-43 flow distribution for calculating the correction factor. In case 3, controller 100 compares the measured data points with the modeled data points and identifies the alignment with the calibration table corresponding to the 60-40 flow distribution. Thus, controller 100 selects the 60-40 flow distribution for calculating the correction factor. Controller 100 can interpolate between other tables or models based on other readings from pressure sensor 16.

[0205] Figure 13 Shows example graphs 1302-1308, which depict the monitoring data for a model-based method for Figure 8 matching the 50-50 flow distribution data with the corresponding flow distribution table. Graph 1302 and Figures 14-16 other graphs (such as graphs 1402, 1502, and 1602) represent the predicted flow distribution between the branches of the post-processing system 22. As shown, controller 100 is able to use the Figure 8 model-based method to match the 50-50 flow distribution data with the 50-50 flow distribution table. Index 1 of graph 1302 represents or corresponds to the 50-50 flow distribution table.

[0206] Figure 14 Shows example graphs 1402-1408, which depict the monitoring data for a model-based method for Figure 8 matching the 40-60 flow distribution data with the corresponding flow distribution table. As shown, controller 100 is able to use the Figure 8 model-based method to match the 40-60 flow distribution data with the 40-60 flow distribution table. Index 5 of graph 1402 represents or corresponds to the 40-60 inlet flow distribution table. In graph 1404, the update can be paused near time 500 to time 2250 because the temperature or exhaust gas mass flow minimum threshold is not met.

[0207] Figure 15Shows example curves 1502 - 1508, which depict monitoring data for a Figure 8 model - based method that matches 60 - 40 flow allocation data with at least one corresponding flow allocation table. As shown, the controller 100 is capable of using a Figure 8 model - based method to match the 60 - 40 flow allocation data with at least one of the 55 - 45 or 60 - 40 flow allocation tables. Index 6 of curve 1502 represents or corresponds to the 55 - 45 outlet flow allocation table, and index 8 of curve 1502 represents or corresponds to the 60 - 40 outlet flow allocation table.

[0208] Figure 16 Shows example curves 1602 - 1608, which depict monitoring data for a Figure 8 model - based method that matches TC NRTC 50 - 50 flow allocation data (e.g., mock - up data or test data) with a corresponding flow allocation table. As shown, the controller 100 is capable of using a Figure 8 model - based method to match the TC NRTC 50 - 50 flow allocation data with the 50 - 50 flow allocation table. Index 5 of curve 1602 represents or corresponds to the 50 - 50 flow allocation table. Figure 13 Depicts a steady - state cycle (e.g., curve 1306), but Figure 16 depicts a transient cycle (e.g., curve 1606).

[0209] Now referring to Figure 17 , depicts an overview process flow diagram of another example process 1700 for mass flow allocation in a multi - branch after - treatment system of an engine system that uses NO x measurement results for management Figure 1 . Figure 17 The processes, operations, or steps of Figures 1-16 can be done, operated, or executed by components of the system 10, a data processing system, a cloud computing environment, or any other computing device described herein in connection with Figures 1-16 (e.g., the controller 100, the I / O device 120, the after - treatment system 22, sensors, etc.). For example, additional or alternative operations of process 1700 can be performed by one or more circuits of the controller 100. Additionally or alternatively, some operations of process 1700 can be performed by a remote device (such as a remote data processing system). Some operations of process 1700 can involve the controller 100 receiving data from components of the after - treatment system 22 (such as one or more sensors) and forwarding the data to a remote device for processing, or vice versa.

[0210] In step 1702, the controller (e.g., NO xThe circuit 107 calculates the first NO of the first branch 22A x conversion efficiency. The controller 100 calculates the first NO x conversion efficiency based on the difference between the amount / level of NO at the inlet of the first branch 22A or upstream of the first catalyst member (e.g., the first SCR catalyst member) and the amount of NO x at the outlet of the first branch 22A or downstream of the first catalyst member. x

[0211] In step 1704, the controller (e.g., the NO x circuit 107) calculates the second NO of the second branch 22B x conversion efficiency. The controller 100 calculates the second NO x conversion efficiency based on the difference between the amount of NO at the inlet of the second branch 22B or upstream of the second catalyst member (e.g., the second SCR catalyst member) and the amount of NO x at the outlet of the second branch 22B or downstream of the second catalyst member. x

[0212] In step 1706, the controller (e.g., the NO x circuit 107) calculates the average / mean NO x conversion efficiency based on the first NO x conversion efficiency and the second NO x conversion efficiency (e.g., the average between these two NO x conversion efficiencies). In step 1708, the controller (e.g., the NO x circuit 107) is configured to calculate the difference between the first NO x conversion efficiency and the second NO x conversion efficiency. The controller 100 is configured to calculate the average NO x conversion efficiency and, after determining that the ratio of ammonia to NO x between the first branch 22A and the second branch 22B is similar, calculate the difference. Having a similar ANR indicates that the branches should have similar NO x conversion efficiencies. Thus, if the average NO x conversion efficiency is below a threshold, or if the difference between the first NO x conversion efficiency and the second NO x conversion efficiency is greater than a threshold, this indicates a restriction in the tailpipe.

[0213] In step 1710, in response to determining that the average NO x conversion efficiency is less than a first threshold or the first NO x conversion efficiency and the second NO x ​​The difference between the conversion efficiencies is greater than a first threshold, and a controller (e.g., the correction circuit 109) is configured to calculate an adjustment factor for balancing an estimated first mass flow rate and an estimated second mass flow rate. The adjustment factor can be based on the ANR of the low NO x conversion efficiency branch. For example, if the ANR of the low NO x conversion efficiency branch is greater than (or equal to) a threshold, this indicates the presence of ammonia slip from the low NO x conversion efficiency branch. In other cases, if the ANR of the low NO x conversion efficiency branch is less than the threshold, this indicates that there is no NO x slip from the low NO x conversion efficiency branch. The adjustment factor can be predefined based on the presence of ammonia slip or NO x slip.

[0214] In step 1712, a controller (e.g., the flow circuit 108 or the correction circuit 109) is configured to use the adjustment factor to estimate an adjusted first mass flow rate of the exhaust gas in the first branch 22A and an adjusted second mass flow rate of the exhaust gas in the second branch 22B. If there is an indication of ammonia slip, the controller 100 estimates the adjusted mass flow rate by reducing the estimated mass flow rate. If there is an indication of NO x slip, the controller 100 estimates the adjusted mass flow rate by increasing the estimated mass flow rate.

[0215] In step 1714, a controller (e.g., the adjustment circuit 111) is configured to adjust at least one of the reductant dosing, hydrocarbon dosing, or soot load estimation based on the adjusted first mass flow rate and the adjusted second mass flow rate. In various embodiments, the Figure 18 operation, technique, or feature of process 1700 can be described in further detail.

[0216] Now referring to Figure 18 , as described in further detail, a process flow diagram of an example process 1800 for managing mass flow rate distribution in a multi-branch aftertreatment system associated with Figure 17 is depicted. Figure 18 The process, operation, or step of Figures 1-17components of any other computing device described (e.g., controller 100, I / O device 120, post-processing system 22, sensors, etc.) to complete, operate, or execute. For example, additional or alternative operations of process 1800 may be performed by one or more circuits of controller 100. Additionally or alternatively, some operations of process 1800 may be performed by a remote device (such as a remote data processing system). Some operations of process 1800 may involve controller 100 receiving data from components of post-processing system 22 (such as one or more sensors) and forwarding the data to a remote device for processing, or vice versa.

[0217] Process 1800 begins at step 1802. Process 1800 may be performed before or after determining that the flow distribution is unbalanced. In addition to Figure 8 process 800, or in place of process 800, process 1800 may be performed. At step 1802, controller 100 is configured to initiate a cleaning operation for a catalyst component (e.g., DPF component 40, SCR catalyst component 50, etc.). After the catalyst component has been cleaned (e.g., soot loading or deposit accumulation factors regarding the unbalanced system have been removed), controller 100 proceeds to step 1804.

[0218] At step 1804, controller 100 determines whether the ratio of average ammonia to NO x (ANR) is similar between the branches. For example, ANR can be measured in moles, where 1.1 moles represents 1.1 times the amount of ammonia (e.g., reductant) present compared to NO x . Having an ANR of approximately 1 (e.g., 0.9 - 1.1, 0.95 - 1.05, 0.98 - 1.02, etc.) provides a desired ratio of reductant to NO x such that the amounts of reductant and NO x at the tailpipe are below the desired levels (e.g., when the mass flow rate estimate is accurate). If the ANR is similar between the branches, process 1800 proceeds to step 1806. In other cases, process 1800 remains at step 1804, and controller 100 determines whether the ANR is similar between the branches at another time interval.

[0219] In various embodiments, in a system without restrictions at the tailpipe, having a similar ANR between the branches results in an average conversion efficiency greater than or equal to a conversion efficiency threshold (e.g., NO between the branches xconversion efficiency). Additionally, in a system without a restriction at the tailpipe, there is a difference less than or equal to another threshold between the conversion efficiencies of the first branch 22A and the second branch 22B that have similar ANR between the branches. However, as discussed herein, if the ANR between the branches is similar and at least one of the average conversion efficiency or the difference between the conversion efficiencies exceeds an expected level (e.g., in step 1808), then the controller 100 is configured to determine that there is a restriction in the tailpipe that results in an inaccurate estimate of the mass flow rate. An inaccurate estimate of the mass flow rate results in an incorrect dosing rate of the reductant. The incorrect dosing rate results in NO x slip or reductant slip (e.g., ammonia slip), or at least one of them. NO x slip or reductant slip corresponds to an amount of NO x or reductant that is higher than the expected level at the tailpipe. Thus, as discussed herein, the conversion efficiency of the branches can be used to determine whether there is a restriction in the tailpipe and to calculate an adjustment factor to correct / adjust the estimated mass flow rate and / or dosing rate of the reductant.

[0220] In some cases, the system 10 can be implemented or configured with an ammonia sensor (not shown). The ammonia sensor can be positioned downstream of the catalytic component (e.g., DPF component 40, SCR catalytic component 50, etc.) of the corresponding branch. The ammonia sensor can be positioned at the tailpipe of the corresponding branch. In this case, with similar ANR between the branches, the controller 100 is configured to monitor (e.g., using the ammonia sensor or the NO x sensor 12) the difference in the levels of ammonia and / or NO x between each branch. If the difference between the branches is greater than or exceeds a threshold, the controller 100 determines that there is a restriction in the tailpipe of at least one of the branches that results in an incorrect mass flow rate estimate. For example, similar to using NO x conversion efficiency, the controller 100 can use the level of the reductant or NO x slip to calculate an adjustment factor for correcting the estimated mass flow rate or dosing rate.

[0221] In step 1806, the controller 100 (e.g., the NO x circuit 107) is configured to calculate / operate the mean or average NO x conversion efficiency (CE) between the first branch 22A and the second branch 22B. To calculate the average value, the controller 100 is configured to calculate the first NO x conversion efficiency of the first branch 22A and the second NO x conversion efficiency of the second branch 22B. The NO x conversion efficiency of each branch is based on the amount of NO x at the inlet of the branch and the NO at the outlet of the branch.x is determined by the difference between the amounts. The controller 100 is based on the first NO x conversion efficiency and the second NO x conversion efficiency to calculate the average NO x conversion efficiency. In addition, the controller 100 is configured to calculate the difference in NO x conversion efficiency between the branches.

[0222] In step 1808, the controller 100 (e.g., the NO x circuit 107) determines whether the average conversion efficiency is less than a threshold (e.g., a first threshold) or determines whether the difference in NO x conversion efficiency is greater than a threshold. For example, the threshold for the average conversion efficiency can be 80%, 85%, 90%, etc. The threshold for the difference in NO x conversion efficiency can be 10%, 15%, 20%, etc. If at least one of the conditions is true, the process 1800 proceeds to step 1810. In other cases, if both conditions are false, the process 1800 proceeds to step 1832.

[0223] In step 1810, the controller 100 receives the mass flow rate of the sample estimate for each branch for correction adjustment (e.g., to correct / adjust using an adjustment factor). The controller 100 (e.g., the flow circuit 108) can estimate the mass flow rate of each branch based on pressure information (e.g., the catalytic converter output pressure or the pressure difference). In some cases, the controller 100 receives the estimated mass flow rate from a remote computing system that processes pressure data or other data related to the mass flow rate.

[0224] In various arrangements, the controller 100 (e.g., the NO x circuit 107) is configured to compare the calculated first NO x conversion efficiency of the first branch 22A with the calculated second NO x conversion efficiency of the second branch 22B. Based on this comparison, the controller 100 determines which branch has a lower NO x conversion efficiency. The branch with the lower NO x conversion efficiency can be referred to as the low conversion efficiency branch (e.g., the low NO x conversion efficiency branch). In addition, the controller 100 determines the ANR of the low conversion efficiency branch.

[0225] In step 1812, the controller 100 (e.g., the NO xCircuit 107 compares the ANR of the low conversion efficiency branch with a predetermined threshold (e.g., the second threshold). This threshold can be predefined by the administrator of system 10 or configured via the operator I / O device 120. The threshold can be predefined as 1 mole, 1.1 moles, 0.9 moles, etc. For example, for a low conversion efficiency branch (e.g., less than 80% conversion efficiency), an ANR less than 0.9 can indicate NO x slip at the tailpipe. In another example, for a low conversion efficiency branch (e.g., less than 85%-90% conversion efficiency), an ANR of 1.3 can indicate NH 3 slip at the tailpipe. The comparison of the ANR of the low conversion efficiency branch with the threshold indicates whether NO x slip or ammonia slip has occurred. For example, if the ANR of the low conversion efficiency branch is greater than (or in some cases equal to) the threshold, the controller 100 determines that there is ammonia slip from the low conversion efficiency branch because in the ANR, the proportion of ammonia is higher than that of NO x . In this case, process 1800 proceeds to step 1814. Conversely, if the ANR is less than the threshold, the controller 100 determines that there is NO x slip from the low conversion efficiency branch because in the ANR, the proportion of ammonia is lower than that of NO x . In response to identifying or determining that there is NO x slip from the low conversion efficiency branch, process 1800 proceeds to step 1816.

[0226] In step 1814, the controller 100 (e.g., adjustment circuit 111) is configured to adjust the dosing rate of the reductant based on the ammonia slip from the low conversion efficiency branch. For example, the controller 100 can reduce the dosing rate due to ammonia slip (e.g., caused by over-dosing of the reductant). In this case, the over-dosing of the reductant is due to an overestimation of the mass flow rate. The controller 100 can use a predetermined adjustment factor to reduce the estimated mass flow rate of the low conversion efficiency branch (e.g., called the adjusted mass flow rate). For example, a correction factor of 1.1 (e.g., correction multiplication factor) can be initially used to increase the mass flow rate, or a correction factor of 0.9 can be initially used to reduce the mass flow rate. In response to the adjustment, the controller 100 reduces the dosing rate of the reductant in proportion to the reduction in the estimated mass flow rate. In some cases, the controller 100 is configured to reduce the dosing rate by a predetermined amount in response to ammonia slip. The predetermined amount can be configured by the administrator of system 10, such as reducing the dosing rate by 10%, 20%, 30%, etc., or reducing it by a predetermined rate. In this case, the dosing rate or the estimated mass flow rate of another branch different from the low conversion efficiency branch may not be adjusted because the incorrect estimate is on the low conversion efficiency branch.

[0227] At step 1816, in response to determining that the ANR of the low conversion efficiency branch is below a threshold, the controller 100 is configured to adjust the dosing rate of the reducing agent by increasing the dosing rate. A low ANR (e.g., ANR below the threshold) for the low conversion efficiency branch indicates the presence of NO x slip. Accordingly, the controller 100 is configured to increase the dosing rate by a predetermined amount in response to NO x slip.

[0228] NO x slip may be the result of an underestimated mass flow. In such a case, in response to determining that the average conversion efficiency is less than a threshold (e.g., a first threshold) or the difference between the conversion efficiency of the branch (e.g., a first NO x conversion efficiency and a second NO x conversion efficiency) is greater than a threshold, the controller 100 is configured to calculate an adjustment factor for balancing at least one of the estimated first mass flow of the first branch 22A or the estimated second mass flow of the second branch 22B. The adjustment factor may be predetermined by the administrator to reduce the estimated mass flow in the case of ammonia slip and increase the estimated mass flow in the case of NO x slip. In such a case, the controller 100 applies the adjustment factor to the estimated mass flow of the low conversion efficiency branch to increase the reducing agent dosing rate based on NO x slip. In response to this adjustment, the controller 100 is configured to increase the reducing agent dosing rate based on the increased (e.g., adjusted) mass flow.

[0229] At step 1818, the controller 100 (e.g., the NO x circuit 107) is configured to determine whether the low conversion efficiency branch has improved after applying the adjustment factor or adjusting the dosing rate of the reducing agent. To determine whether the low conversion efficiency branch has improved, the controller 100 calculates a third NO x conversion efficiency of the low NO x conversion efficiency branch after adjusting the dosing rate of the reducing agent. The controller 100 compares the third NO x conversion efficiency with a threshold (e.g., a third threshold), which may be similar to the thresholds described in step 1608 or 1612. If the third conversion efficiency is less than the threshold, the low conversion efficiency branch has not improved and the process 1800 proceeds to step 1822. If the third conversion efficiency is greater than or equal to the threshold, the low conversion efficiency branch has improved and the process 1800 proceeds to step 1820.

[0230] In various arrangements, to determine whether the low conversion efficiency branch is improved, the controller 100 compares the ANR of the low conversion efficiency branch after adjusting the dosing rate (e.g., the new ANR) with a threshold (e.g., the third threshold). The threshold can be based on the ANR of the low conversion efficiency branch before the adjustment, such as a predefined percentage or a certain amount of improvement relative to the previous ANR. The threshold can be a conversion efficiency threshold. In some cases, the controller 100 compares the new ANR with the previous ANR CE to determine whether to maintain the correction factor. The controller 100 can apply one or more subsequent correction factors until the previous value increases to the desired threshold.

[0231] In step 1820, the controller 100 is configured to reset the value of the number of iterations of the dosing rate readjustment that has been performed (e.g., incremented in step 1822). After resetting this value, the process 1800 proceeds to step 1832.

[0232] In step 1822, the controller 100 determines that the low conversion efficiency branch has not been improved due to incorrect adjustment (e.g., the direction or amount of adjustment). The controller 100 increments the value of the number of iterations indicating that the dosing rate has been adjusted (e.g., in this case, the value after incrementing = 1).

[0233] In step 1824, the controller 100 determines whether the dosing rate of the reducing agent has been adjusted once. If the dosing rate has been adjusted once (e.g., value = 1), the process 1800 proceeds to step 1826. In other cases, if the dosing rate has been adjusted more than once (e.g., value > 1), the process 1800 proceeds to step 1828, for example.

[0234] In step 1826, the controller 100 readjusts the dosing rate of the reducing agent in response to determining that the low conversion efficiency branch has not been improved after the initial adjustment. The controller 100 is configured to adjust the dosing rate by a predetermined amount. Since the dosing rate may be over-adjusted, the controller 100 is configured to readjust the dosing by reducing the initial adjustment amount. For example, if the dosing rate has increased (e.g., in step 1816), the controller 100 is configured to proportionally reduce the adjusted dosing rate by the increased amount (e.g., half, one-third, one-fourth, etc. of the increased amount). In some cases, the controller 100 reapplies the initial adjustment factor or replaces the initial adjustment factor with a different adjustment factor to adjust the estimated mass flow rate. The second adjustment factor can be less than the initial adjustment factor such that the correction step size is reduced (e.g., the dosing rate is increased by a lower amount).

[0235] In another example, if the dosing rate has been reduced (e.g., in step 1814), the controller 100 is configured to increase the adjusted dosing rate proportionally to the reduced amount (e.g., half, one-third, one-fourth, etc. of the reduced amount). In some cases, the controller 100 reapplies the initial adjustment factor or replaces the initial adjustment factor with a different adjustment factor to adjust the estimated mass flow rate. The second adjustment factor can be less than the initial adjustment factor such that the correction step size is reduced (e.g., the dosing rate is reduced by a lower amount).

[0236] Returning to step 1818, the controller 100 determines whether the low conversion efficiency branch has improved after readjusting the dosing rate of the reductant (e.g., reducing the correction step size). To perform this determination, the controller 100 calculates the fourth NO x conversion efficiency of the low conversion efficiency branch and compares this fourth NO x conversion efficiency to another threshold (e.g., a fourth threshold). This threshold can be similar to or different from the third threshold. In some cases, the controller 100 determines the ANR of the low conversion efficiency branch after readjustment. If the low conversion efficiency branch has improved (e.g., the NO x conversion efficiency or ANR has improved), then process 1800 proceeds to step 1820. If the low conversion efficiency branch still has not improved, then process 1800 proceeds to step 1822 and the value is incremented. In this step, since the value is greater than 1, the process proceeds to step 1828.

[0237] In step 1828, the controller 100 resets the correction adjustment (e.g., the adjustment of the dosing rate) and the value regarding the number of adjustments made to the dosing rate.

[0238] In step 1830, the controller 100 triggers a fault and proceeds to step 1832. The controller 100 triggers a fault in response to determining that the fourth NO x conversion efficiency is less than the fourth threshold. Triggering a fault can include the controller 100 transmitting a signal or message to the operator I / O device 120 indicating that there is a limitation or imbalance in the aftertreatment system 22 and accessing the service center. In some cases, for example, the signal or message can be transmitted to a device at the service center for diagnosis or scheduling a service appointment. In certain cases, the triggered fault can be a service light on the instrument panel of the vehicle including the system 10.

[0239] In step 1832, the controller 100 is configured to pause or stop operations in process 1800 and resume operations by proceeding to step 1804. In some cases, if an imbalance is diagnosed or resolved after another iteration of process 1800 (e.g., the estimated mass flow is corrected), the controller 100 may reset the triggered fault. In various embodiments, by adjusting or correcting the estimated mass flow, the controller 100 is configured to further adjust at least one of hydrocarbon dosing or soot loading estimation based on the adjusted mass flow of at least one of the branches.

[0240] In various embodiments, in response to resolving the ANR and / or conversion efficiency of a low conversion efficiency branch, the low conversion efficiency branch becomes a high (or normal) conversion efficiency branch, while the other branch may be a low conversion efficiency branch. Process 1800 may be repeated for the other branch (e.g., correcting the estimated mass flow of the other branch).

[0241] Reference Figure 19 , shows an example process 1900 of calibration associated with Figure 18 based on NO x monitoring. Graph 1902 shows an increase in engine exhaust mass flow at various time intervals. Graph 1904 shows an increase in the bed temperature of a catalytic member (e.g., SCR catalytic member 50) corresponding to the increased engine exhaust mass flow at various time intervals. A sudden increase in temperature can cause ammonia slip at the tailpipe of the corresponding branch. The sudden increase in engine exhaust mass flow and catalytic temperature may be due to a mass flow estimation error with a tailpipe restriction.

[0242] As shown in graph 1906, the conversion efficiency and ANR between the two branches (e.g., of SCR catalytic member 50) can be used as conditions indicating an imbalanced system. For example, in the time range between 4.26 hours and 4.29 hours, the conversion efficiency of the two branches (e.g., average conversion efficiency) is below a predetermined threshold (e.g., below 95%, 90%, etc.), or the difference between the conversion efficiencies is greater than or equal to a threshold (e.g., greater than 3%, 5%, etc.). Additionally, in the same time range, the ANR between the first branch 22A and the second branch 22B is similar (e.g., approximately 1 - 1.25). Meeting the conditions indicates that the mass flow estimation is incorrect for a tailpipe with a restriction.

[0243] Graph 1908 shows NOx measurement results (e.g., in parts per million (ppm)), and graph 1910 shows the reductant dosing amount (e.g., estimated by controller 100 or measured by an ammonia sensor) during the same time range as graph 1906. As shown, for a given NO xHorizontally, as compared to the NO passing through the system x Horizontally, the second branch 22B provides an excessive amount of reducing agent.

[0244] Graph 1912 shows the estimated mass flow rates in the same time window as Graphs 1906 - 1910. As shown, the estimated mass flow rates of both the first branch and the second branch 22B increase from 9 kg / min to 20 kg / min - 22 kg / min at approximately 4.24 - 4.25 hours. In this case, due to the tailpipe restriction, the estimated mass flow rate is inaccurate for at least one of the branches. Therefore, the controller 100 is configured to perform the operations described in process 1800 to correct the estimated mass flow rate and adjust the dosing rate of the reducing agent to minimize NO x and reducing agent slip. In this case, the second branch 22B is a low - flow branch but is estimated as a high - flow branch, while the first branch 22A is a high - flow branch but is estimated as a low - flow branch relative to the second branch 22B.

[0245] Graph 1914 shows the adjusted estimated mass flow rates after applying the adjustment / correction factor to the first branch 22A and / or the second branch 22B. For example, due to the overestimated mass flow rate, there is reducing agent slip from the second branch 22B, and due to the underestimated mass flow rate, there is ammonia slip in the first branch 22A. In this case, the correction factor applied to the branches includes reducing the estimated mass flow rate of the second branch 22B and increasing the estimated mass flow rate of the first branch 22A by a predetermined amount proportional to the overestimation or underestimation of the estimated mass flow rate. The amount of overestimation or underestimation can be based on the NO x slip or the level of reducing agent slip.

[0246] Graph 1916 shows the reducing agent dosing rate, and Graph 1918 shows the measured NOx levels in the same time window as Graph 1914 after adjustment. As shown, after applying the adjustment / correction factor, the reducing agent dosing has been improved. Based on the improvement results from the correction, further correction (e.g., increasing the adjustment factor) can be initiated or the correction can be maintained. Therefore, as shown in Graph 1920, after applying the adjustment factor, the conversion efficiency of the first branch 22A and the second branch 22B has been improved.

[0247] III. Construction of the Example Embodiment

[0248] Although this specification contains many specific implementation details, these should not be construed as limitations on the scope of what may be claimed, but rather as descriptions of features specific to particular embodiments. Certain features described in the context of separate embodiments in this specification may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented separately or in any suitable sub-combination in multiple embodiments. Additionally, although features may be described as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination may in some cases be excluded from the combination, and the claimed combination may be directed to a sub-combination or a variation of a sub-combination.

[0249] As used herein, the terms "substantially", "approximately", "about" and similar terms are intended to have a broad meaning consistent with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. Those skilled in the art reviewing this disclosure should understand that these terms are intended to allow the description of certain features being described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that non-substantive or immaterial modifications or variations to the subject matter being described and claimed are considered to be within the scope of the invention as recited in the appended claims.

[0250] As used herein, the term "coupled" and the like refer to two components being directly or indirectly joined to each other. Such joining can be stationary (e.g., permanent) or movable (e.g., removable or releasable). Such joining can be achieved in cases where the two components or the two components and any additional intermediate components are integrally formed as a single unit, or where the two components or the two components and any additional intermediate components are attached to each other.

[0251] As used herein, the term "fluidly coupled to" and the like refer to two components or objects having a path formed therebetween through which a fluid (e.g., air, exhaust gas, liquid reductant, gaseous reductant, aqueous reductant, gaseous ammonia, etc.) can flow with or without intermediate components or objects. Examples of fluid connectors or configurations for achieving fluid communication can include pipes, channels or any other suitable components for enabling the flow of fluid from one component or object to another.

[0252] It is important to note that the construction and arrangement of the systems shown in the various exemplary embodiments are illustrative only and not restrictive in nature. All changes and modifications falling within the spirit and / or scope of the described embodiments are desired to be protected. It should be understood that some features may not be necessary and embodiments lacking various features may be envisioned as being within the scope of this application, which is defined by the appended claims. When the language "a portion" is used, unless otherwise clearly stated, an item can include a portion of the item and / or the whole item.

[0253] In addition, the term "or" is used in its inclusive sense (rather than in its exclusive sense), such that when used, for example, to connect a list of elements, the term "or" means one, some, or all of the elements in the list. Unless otherwise specifically stated, conjunctive language such as the phrase "at least one of X, Y, and Z" is understood in context to generally convey that items, terms, etc. can be X, Y, Z, X and Y, X and Z, Y and Z, or X, Y, and Z (i.e., any combination of X, Y, and Z). Thus, unless otherwise indicated, such conjunctive language is generally not intended to imply that certain embodiments require the presence of at least one of each of X, at least one of each of Y, and at least one of each of Z.

[0254] Additionally, unless otherwise stated, value ranges used herein (e.g., W to P, etc.) include their maximum and minimum values (e.g., W to P includes W and includes P, etc.). Further, unless otherwise stated, value ranges (e.g., W to P, etc.) do not necessarily require the inclusion of intermediate values within the value range (e.g., W to P can include only W and P, etc.).

Claims

1. A post-treatment system, comprising: a first branch, the first branch including one or more first post-treatment components; a second branch, the second branch including one or more second post-treatment components; and a controller configured to: estimate a first mass flow rate of exhaust gas in the first branch; estimate a second mass flow rate of exhaust gas in the second branch; calculate an estimated total mass flow rate based on the estimated first mass flow rate and the estimated second mass flow rate; in response to determining that the estimated total mass flow rate is greater than the engine exhaust mass flow rate, calculate a correction factor for balancing the estimated first mass flow rate and the estimated second mass flow rate; use the correction factor to estimate a corrected first mass flow rate of exhaust gas in the first branch and a corrected second mass flow rate of exhaust gas in the second branch; and adjust at least one of reductant dosing, hydrocarbon dosing, or soot loading estimation based on the corrected first mass flow rate and the corrected second mass flow rate.

2. The post-treatment system according to claim 1, wherein the controller is further configured to: in response to determining that the estimated total mass flow rate is greater than the engine exhaust mass flow rate and before calculating the correction factor, regenerate at least one of: a first selective catalytic reduction (SCR) catalyst in the one or more first post-treatment components or a second SCR catalyst in the one or more second post-treatment components.

3. The post-treatment system according to claim 2, wherein after regenerating at least one of the first SCR catalyst or the second SCR catalyst and before calculating the correction factor, the controller is further configured to: estimate a third mass flow rate of exhaust gas in the first branch; estimate a fourth mass flow rate of exhaust gas in the second branch; and calculate a second estimated total mass flow rate based on the third mass flow rate and the fourth mass flow rate.

4. The post-treatment system according to claim 1, wherein in response to determining that the estimated total mass flow rate is greater than the engine exhaust mass flow rate, the controller is further configured to: determine whether the first branch or the second branch is newly installed; and in response to determining that the first branch or the second branch is newly installed, calculate the correction factor.

5. The post-treatment system according to claim 1, wherein to calculate the correction factor, the controller is configured to: determine a ratio between a first pressure difference across a first particulate filter in the one or more first post-treatment components and a second pressure difference across a second particulate filter in the one or more second post-treatment components; and calculate the correction factor based on the ratio between the first pressure difference and the second pressure difference.

6. The post-treatment system according to claim 1, wherein in response to determining that the estimated total mass flow rate is greater than the engine exhaust mass flow rate, the controller is further configured to: determine whether the first branch or the second branch is newly installed; In response to determining that neither the first branch nor the second branch is newly installed, estimate the soot load flow rate; and Calculate the correction factor based on the estimated soot load flow rate.

7. The aftertreatment system according to claim 1, wherein, The controller is further configured to: Estimate a first virtual mass flow rate of the exhaust gas in the first branch based on a first pressure difference across a first particulate filter in the one or more first aftertreatment components; Estimate a second virtual mass flow rate of the exhaust gas in the second branch based on a second pressure difference across a second particulate filter in the one or more second aftertreatment components; and Calculate the correction factor based on at least one of the estimated first virtual mass flow rate or the estimated second virtual mass flow rate and the engine exhaust mass flow rate.

8. The aftertreatment system according to claim 1, wherein, The controller is further configured to: Determine a first pressure difference across a first particulate filter in the one or more first aftertreatment components and a second pressure difference across a second particulate filter in the one or more second aftertreatment components within a time window including a plurality of time intervals; and In each of the plurality of time intervals, compare the first pressure difference and the second pressure difference with a set of calibration tables, the set of calibration tables including a plurality of predetermined pressure differences for different flow rate distributions of the engine exhaust mass flow rate; and At the end of the time window, calculate the correction factor based on the comparison between the first pressure difference and the second pressure difference and the set of calibration tables.

9. The aftertreatment system according to claim 8, wherein, To calculate the correction factor, the controller is further configured to: In each of the plurality of time intervals of the time window, in response to the first pressure difference and the second pressure difference matching one of the calibration tables in the set of calibration tables, increment the score of the one calibration table in the set of calibration tables; and At the end of the time window, select the flow rate distribution corresponding to the calibration table in the set of calibration tables having the highest score to calculate the correction factor.

10. A method, comprising: Estimate, by a controller, a first mass flow rate of the exhaust gas in a first branch including one or more first aftertreatment components; Estimate, by the controller, a second mass flow rate of the exhaust gas in a second branch including one or more second aftertreatment components; Calculate, by the controller, an estimated total mass flow rate based on the estimated first mass flow rate and the estimated second mass flow rate; In response to determining that the estimated total mass flow rate is greater than the engine exhaust mass flow rate, calculate, by the controller, a correction factor for balancing the estimated first mass flow rate and the estimated second mass flow rate; Estimate, by the controller, a corrected first mass flow rate of the exhaust gas in the first branch and a corrected second mass flow rate of the exhaust gas in the second branch using the correction factor; and The controller adjusts at least one of reductant dosing, hydrocarbon dosing, or soot load estimation based on the corrected first mass flow rate and the corrected second mass flow rate.

11. The method according to claim 10, further comprising: Prior to calculating the correction factor and in response to determining that the estimated total mass flow rate is greater than the engine exhaust mass flow rate, the controller regenerates at least one of: a first selective catalytic reduction (SCR) catalyst in the one or more first aftertreatment components or a second SCR catalyst in the one or more second aftertreatment components.

12. The method according to claim 11, wherein, After regenerating at least one of the first SCR catalyst or the second SCR catalyst and prior to calculating the correction factor, the method further comprises: The controller estimates a third mass flow rate of the exhaust gas in the first branch; The controller estimates a fourth mass flow rate of the exhaust gas in the second branch; and The controller calculates a second estimated total mass flow rate based on the third mass flow rate and the fourth mass flow rate.

13. The method according to claim 10, wherein, In response to determining that the estimated total mass flow rate is greater than the engine exhaust mass flow rate, the method comprises: The controller determines whether the first branch or the second branch is newly installed; and In response to determining that the first branch or the second branch is newly installed, the controller calculates the correction factor.

14. The method according to claim 10, wherein, Calculating the correction factor comprises: The controller determines a ratio between a first pressure difference across a first particulate filter in the one or more first aftertreatment components and a second pressure difference across a second particulate filter in the one or more second aftertreatment components; and The controller calculates the correction factor based on the ratio between the first pressure difference and the second pressure difference.

15. The method according to claim 10, wherein, In response to determining that the estimated total mass flow rate is greater than the engine exhaust mass flow rate, the method comprises: The controller determines whether the first branch or the second branch is newly installed; In response to determining that neither the first branch nor the second branch is newly installed, the controller estimates a soot load flow rate; and The controller calculates the correction factor based on the estimated soot load flow rate.

16. The method according to claim 10, further comprising: The controller estimates a first virtual mass flow rate of the exhaust gas in the first branch based on a first pressure difference across a first particulate filter in the one or more first aftertreatment components; The controller estimates a second virtual mass flow rate of the exhaust gas in the second branch based on a second pressure difference across a second particulate filter in the one or more second aftertreatment components; and The correction factor is calculated by the controller based on at least one of the estimated first virtual mass flow rate or the estimated second virtual mass flow rate and the engine exhaust mass flow rate.

17. The method according to claim 10, further comprising: Within a time window including a plurality of time intervals, the controller determines a first pressure difference across a first particulate filter in the one or more first aftertreatment components and a second pressure difference across a second particulate filter in the one or more second aftertreatment components; In each of the plurality of time intervals, the controller compares the first pressure difference and the second pressure difference with a set of calibration tables, the set of calibration tables including a plurality of predetermined pressure differences for different flow rate distributions of the engine exhaust mass flow rate; and At the end of the time window, the controller calculates the correction factor based on the comparison between the first pressure difference and the second pressure difference and the set of calibration tables.

18. The method according to claim 17, wherein, Calculating the correction factor includes: In each of the plurality of time intervals of the time window, in response to the first pressure difference and the second pressure difference matching one of the calibration tables in the set of calibration tables, the controller increments the score of the one calibration table in the set of calibration tables; and At the end of the time window, the controller selects the flow rate distribution corresponding to the set of calibration tables with the highest score to calculate the correction factor.

19. An aftertreatment system, comprising: A first branch including one or more first aftertreatment components; A second branch including one or more second aftertreatment components; and A controller configured to: Calculate a first NOx conversion efficiency of the first branch; Calculate a second NOx conversion efficiency of the second branch; Calculate an average NOx conversion efficiency based on the first NOx conversion efficiency and the second NOx conversion efficiency; Calculate the difference between the first NOx conversion efficiency and the second NOx conversion efficiency; In response to determining that the average NOx conversion efficiency is less than a first threshold or the difference between the first NOx conversion efficiency and the second NOx conversion efficiency is greater than the first threshold, calculate an adjustment factor for balancing the estimated first mass flow rate and the estimated second mass flow rate; Use the adjustment factor to estimate an adjusted first mass flow rate of the exhaust gas in the first branch and an adjusted second mass flow rate of the exhaust gas in the second branch; and Adjust at least one of the reductant dosing, hydrocarbon dosing, or soot load estimation based on the adjusted first mass flow rate and the adjusted second mass flow rate.

20. The aftertreatment system according to claim 19, wherein, In response to determining that the average NOx conversion efficiency is less than the first threshold or the difference between the first NOx conversion efficiency and the second NOx conversion efficiency is greater than the first threshold, the controller is further configured to: Based on the calculated first NOx conversion efficiency and the calculated second NOx conversion efficiency, identify a low NOx conversion efficiency branch from one of the first branch or the second branch; Determine the ratio of ammonia (NH 3 ) to NOx (ANR) in the low NOx conversion efficiency branch; Compare the ANR of the low NOx conversion efficiency branch with a second threshold; Identifying NOx slip in response to determining that the ANR of the low NOx conversion efficiency branch is less than the second threshold, or identifying NH 3 slip in response to determining that the ANR of the low NOx conversion efficiency branch is greater than or equal to the second threshold; and Based on the NOx slip or the NH 3 slip, calculate the adjustment factor to adjust the dosing rate of the reducing agent in the aftertreatment system.

21. The aftertreatment system according to claim 20, wherein, To adjust the dosing rate of the reducing agent, the controller is further configured to increase the dosing rate of the reducing agent in the aftertreatment system by a first amount in response to the NOx slip, or decrease the dosing rate of the reducing agent in the aftertreatment system by a second amount in response to the NH 3 slip.

22. The aftertreatment system according to claim 20, wherein, the controller is further configured to: After adjusting the dosing rate of the reducing agent, calculate a third NOx conversion efficiency of the low NOx conversion efficiency branch; and In response to determining that the third NOx conversion efficiency is less than a third threshold, readjust the dosing rate of the reducing agent.

23. The aftertreatment system according to claim 22, wherein, the controller is further configured to: After readjusting the dosing rate of the reducing agent, calculate a fourth NOx conversion efficiency of the low NOx conversion efficiency branch; and In response to determining that the fourth NOx conversion efficiency is less than a fourth threshold, trigger a fault.

24. A method, comprising: Calculate, by a controller, a first NOx conversion efficiency of a first branch including one or more first aftertreatment components; Calculate, by the controller, a second NOx conversion efficiency of a second branch including one or more second aftertreatment components; Calculate, by the controller, an average NOx conversion efficiency based on the first NOx conversion efficiency and the second NOx conversion efficiency; Calculate, by the controller, the difference between the first NOx conversion efficiency and the second NOx conversion efficiency; In response to determining that the average NOx conversion efficiency is less than a first threshold or the difference between the first NOx conversion efficiency and the second NOx conversion efficiency is greater than the first threshold, calculate, by the controller, an adjustment factor for balancing an estimated first mass flow rate and an estimated second mass flow rate; Estimate, by the controller, an adjusted first mass flow rate of the exhaust gas in the first branch and an adjusted second mass flow rate of the exhaust gas in the second branch using the adjustment factor; and Adjust, by the controller, at least one of reducing agent dosing, hydrocarbon dosing, or soot loading estimation based on the adjusted first mass flow rate and the adjusted second mass flow rate.

25. The method according to claim 24, wherein, In response to determining that the average NOx conversion efficiency is less than the first threshold or the difference between the first NOx conversion efficiency and the second NOx conversion efficiency is greater than the first threshold, the method further comprises: Identify, by the controller, a low NOx conversion efficiency branch from one of the first branch or the second branch based on the calculated first NOx conversion efficiency and the calculated second NOx conversion efficiency; The controller determines the ratio (ANR) of ammonia (NH 3 ) to NOx in the low NOx conversion efficiency branch; Compare, by the controller, the ANR of the low NOx conversion efficiency branch with a second threshold; In response to determining that the ANR of the low NOx conversion efficiency branch is less than the second threshold, the controller identifies NOx slip, or in response to determining that the ANR of the low NOx conversion efficiency branch is greater than or equal to the second threshold, the controller identifies NH 3 slip; and The controller calculates the adjustment factor based on the NOx slip or the NH 3 slip to adjust the dosing rate of the reducing agent in the aftertreatment system.

26. The method according to claim 25, wherein, Adjusting the dosing rate of the reducing agent includes: The controller increases the dosing rate of the reducing agent in the aftertreatment system by a first amount in response to the NOx slip, or the controller reduces the dosing rate of the reducing agent in the aftertreatment system by a second amount in response to the NH 3 slip.

27. The method according to claim 25, further comprising: After adjusting the dosing rate of the reducing agent, the controller calculates a third NOx conversion efficiency of the low NOx conversion efficiency branch; and In response to determining that the third NOx conversion efficiency is less than a third threshold, the controller readjusts the dosing rate of the reducing agent.

28. The method according to claim 27, further comprising: After readjusting the dosing rate of the reducing agent, the controller calculates a fourth NOx conversion efficiency of the low NOx conversion efficiency branch; and In response to determining that the fourth NOx conversion efficiency is less than a fourth threshold, the controller triggers a fault.

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