DIAGNOSTIC SYSTEM FOR REDUCING AGENT DOSING SYSTEM

Abstract

Methods for diagnosing a reducing agent dosing system (200), comprising: Accessing required dosage data; Accessing estimated flow feedback data, wherein the estimated flow feedback data is based on a parameter that affects the operation of a pump (118) of the metering system; Determine, using a controller (120), an integrated instructed flow rate based on the instructed metering flow rate data and an integrated estimated flow feedback based on the estimated flow feedback; Determine, using the control, a percentage error value in response to and using the integrated directed flow rate and the integrated estimated flow recirculation; Determining, using the control system, an error based on the determined percentage error value and one or more predetermined error limits, wherein the determination has: Determine that the error is a closed-stuck error if the determined percentage error value is equal to or greater than a first predetermined error limit; Determine that the fault is a partial blockage of the pressure line (212) or an injector fault if the determined percentage fault value is equal to or greater than a second predetermined fault limit; Determine that the fault is an open-stuck fault or a fault in a broken pressure line (212) if the determined percentage fault value is equal to or less than a third predetermined fault limit; and Determine that the fault is a leak in the pressure line (212) or an injector fault if the determined percentage fault value is equal to or less than a fourth predetermined fault limit; and Display the detected error.

Description

TECHNICAL AREA

[0001] The present application relates generally to the field of aftertreatment systems for internal combustion engines. More specifically, the present application relates to diagnostic systems for aftertreatment systems. BACKGROUND

[0002] In combustion engines, such as diesel engines, nitrogen oxide compounds (NOx) can be produced. x ) are emitted in the exhaust gas. To reduce NO x To reduce emissions, a selective catalytic reduction (SCR) process can be implemented to reduce NO xThe process involves converting oxidizing compounds into more neutral compounds, such as diatomic nitrogen, water, or carbon dioxide, using a catalyst and a reducing agent. The catalyst can be inserted into a catalyst chamber of an exhaust system, such as that of a vehicle or power generation unit. A reducing agent, such as anhydrous ammonia, hydrated ammonia, or urea, is typically introduced into the exhaust gas flow upstream of the catalyst chamber. To introduce the reducing agent for the SKR process into the exhaust gas flow, an SKR system can meter the reducing agent or otherwise introduce it via a metering module that vaporizes or sprays the reducing agent into an exhaust line of the exhaust system upstream of the catalyst chamber.

[0003] DE 10 2007 039 794 A1 discloses a metering system and a method for metering a liquid reducing agent into the exhaust system of an internal combustion engine. The metering system comprises a metering valve and a metering pump for dispensing the reducing agent and for conveying the dispensed reducing agent to the metering valve. The metering pump is designed to perform individual dispensing operations with an adjustable individual delivery rate. The method provides that, to achieve a reduced reducing agent flow rate compared to a maximum reducing agent flow rate, the metering pump is controlled such that it dispenses a reduced individual delivery rate compared to a maximum individual delivery rate. The invention is particularly suitable for metering aqueous urea solution as a reducing agent for nitrogen oxide reduction. A further reducing agent injection system is known from US 2011 / 0 083 424 A1. SUMMARY

[0004] A method for diagnosing a reducing agent dosing system according to the present invention is specified in claim 1. A system according to the present invention is specified in claim 4. A device according to the present invention is specified in claim 7. Further preferred embodiments are described in the dependent claims.

[0005] One implementation concerns a method for diagnosing a reducing agent dosing system. The method involves accessing instructed dosing data and estimated flow feedback data. It also includes determining an integrated instructed flow rate based on the instructed dosing data and an integrated estimated flow feedback based on the estimated flow feedback. Furthermore, the method includes determining a percentage error value in response to and using the integrated instructed flow rate and the integrated estimated flow feedback. Finally, the method includes determining an error based on the determined percentage error value and one or more predetermined error limits, and displaying the determined error.

[0006] In some implementations, the estimated flow feedback data is based on a parameter affecting the operation of a metering system pump. This parameter may be the pump's speed or cycle rate. The parameter affecting pump operation can be modified to maintain a target pressure in a pressure line leading to a metering module. In some implementations, the fault is a closed-type stuck fault, a fault consisting of a partial blockage of a pressure line or injector, an open-type stuck fault, a fault consisting of a broken pressure line, or a fault consisting of a leak in a pressure line or injector. The closed-type stuck fault and the fault consisting of a partial blockage of a pressure line or injector are determined based on a positive percentage error value.The one or more limit values ​​may include a first limit value of 90% for the closed-stuck fault and a second limit value of 30% for the fault consisting of a partial blockage of the pressure line or an injector. The open-stuck fault, the fault consisting of a broken pressure line, and the fault consisting of a leak in a pressure line or injector are determined based on a negative value of the percentage fault value. The one or more limit values ​​may include a first limit value of -90% for the open-stuck fault or the fault consisting of a broken pressure line, and a second limit value of -30% for the fault consisting of a leak in the pressure line or an injector.

[0007] Another implementation involves a system comprising a pump, a dosing module, and a controller that communicates electrically with the pump and the dosing module. The controller is configured to output a reducing agent pump parameter to control the pump's operation, and a dosing parameter to control the quantity of reducing agent dosed by the dosing module. Furthermore, the controller is configured to access dosing quantity data based on dosing parameters output to the dosing module, and to access estimated reducing agent flow feedback data based on reducing agent pump parameters output to the reducing agent pump.The controller is also configured to determine an integrated instructed flow rate based on the metering data, as well as an integrated estimated flow feedback based on the estimated flow feedback, a percentage error value in response to and using the integrated instructed flow rate and the integrated estimated flow feedback, and to determine an error based on the determined percentage error value and one or more predefined limits. The controller is also configured to display the determined error.

[0008] In some implementations, the system also includes a pressure sensor configured to measure the pressure of a reducing agent supplied to the dosing module by the pump. The controller is also configured to output the reducing agent pump parameters based on data indicating a pressure measured by the pressure sensor. In some implementations, the controller is further configured to output the reducing agent pump parameters based on a target pressure to be maintained in a pressure line to the dosing module. The reducing agent pump parameters may include a parameter indicating the pump speed or cycle count.In some implementations, the fault is a closed-stuck fault, a fault consisting of a partial blockage of a pressure line or injector, an open-stuck fault, a fault consisting of a broken pressure line, or a fault consisting of a leak in a pressure line or injector. The closed-stuck fault and the fault consisting of a partial blockage of a pressure line or injector are determined based on a positive value of the percentage fault value. The one or more thresholds may include a first threshold of 90% for the closed-stuck fault and a second threshold of 30% for the fault consisting of a partial blockage of the pressure line or injector.In some implementations, open-end faults, faults consisting of a broken pressure line, and faults consisting of a leak in a pressure line or injector are determined based on a negative value of the percentage fault value. The one or more limits may include a first limit of -90% for the open-end fault or the fault consisting of a broken pressure line, and a second limit of -30% for the fault consisting of a leak in the pressure line or injector.

[0009] Another implementation involves a device comprising a controller communicating with a pump and a dosing module. The controller is configured to output a reducing agent pump parameter to control the pump's operation, and a dosing parameter to regulate the amount of reducing agent dosed by the dosing module. The controller is also configured to access dosing quantity data based on dosing parameters output to the dosing module, and to access estimated flow feedback data based on reducing agent pump parameters output to the reducing agent pump.The controller is additionally configured to determine an integrated instructed flow rate based on the metering data, as well as an integrated estimated flow feedback based on the estimated flow feedback, to determine a percentage error value in response to and using the integrated instructed flow rate and the integrated estimated flow feedback, and to determine an error based on the determined percentage error rate and one or more predetermined error limits. The controller is also configured to output a display of the determined error.

[0010] The reducing agent pump parameter may include a parameter indicating the pump speed or cycle count. The fault may be a closed-type stuck fault, a fault consisting of a partial blockage of a pressure line or injector, an open-type stuck fault, a fault consisting of a broken pressure line, or a fault consisting of a leak in a pressure line or injector. The closed-type stuck fault and the fault consisting of a partial blockage of a pressure line or injector are determined based on a positive percentage fault value. The one or more limit values ​​may include a first limit value of 90% for the closed-type stuck fault and a second limit value of 30% for the fault consisting of a partial blockage of the pressure line or injector.In some implementations, open-end faults, faults in a broken pressure line, and faults in a pressure line or injector leak are determined based on a negative percentage of the fault value. The one or more limits may include a first limit of -90% for the open-end fault or the fault in a broken pressure line, and a second limit of -30% for the fault in a pressure line or injector leak. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The details of one or more implementations are set forth in the accompanying drawings and the following description. Other features, aspects, and advantages of the disclosure will become apparent from the description, the drawings, and the claims, wherein: Fig. Figure 1 is a schematic block diagram of a selective catalytic reduction system with a reducing agent supply system for an exhaust system; Fig. Figure 2 is a schematic block diagram of part of the selective catalytic reduction system, showing the pump, the metering module, the reducing agent source and the pressure lines in more detail; Fig. Figure 3 is a block diagram of an implementation of an exemplary procedure for identifying a fault using a diagnostic system; Fig. Figure 4 is a series of graphical representations of various values ​​for a specified dosing quantity, an estimated return current, an integrated pump return current and specified dosing current, as well as a determined error percentage in a specific period for a functioning dosing module; Fig. Figure 5 is a series of graphical representations of various values ​​for a specified dosing quantity, an estimated return current, an integrated pump return current and specified dosing current, as well as a determined error percentage in a specific period for a dosing module stuck in the closed state; Fig. Figure 6 is a series of graphical representations of various values ​​for a specified dosing quantity, an estimated return current, an integrated pump return current and specified dosing current, as well as a determined error percentage in a specific time period for a dosing module stuck in the open state; and Fig. Figure 7 is a series of graphical representations of various values ​​for a specified dosing quantity, an estimated return current, an integrated pump return current and specified dosing current, as well as a determined error percentage in a specific time period for a dosing module stuck in the closed state, which is being returned to a normal operating state.

[0012] It is noted that some or all of the figures are schematic representations for illustrative purposes. The figures are provided solely for the purpose of illustrating one or more implementations, with the express understanding that they do not limit the scope or meaning of the claims. DETAILED DESCRIPTION

[0013] More detailed descriptions of various concepts follow, relating to methods, devices, and systems for injecting and mixing reducing agents into the exhaust stream of a vehicle, or to implementations thereof. The various concepts presented above and described in more detail below are not limited to any specific implementation method. Examples of specific implementations and applications are provided primarily for illustrative purposes. I. Overview

[0014] In exhaust systems with SKR systems, a dosing module can be used to dose a reducing agent such as urea, aqueous ammonia, or diesel emission fluid (DEF) into the exhaust system to reduce NOₓ. x -Emissions are reduced through a selective catalytic reduction (SCR) process. This ensures that such dosing modules and / or SCR systems deliver sufficient reducing agent to reduce NO. xTo reduce emissions, the dosing modules and / or SKR systems require that the dosing module opens and closes, is essentially free of blockages and leaks, and is supplied with adequately pressurized reducing agent. Accordingly, diagnosing faults or failures, such as a dosing module stuck in the open or closed position, blockages or leaks in the dosing module and / or pressure line, and / or interrupted pressure lines, can be useful for the SKR system to ensure proper operation.

[0015] An SKR system may include a controller configured to diagnose the aforementioned faults. For example, an SKR system may include a pump that introduces reducing agent from a reducing agent source into the metering module via a pressure line. The line pressure drops when the metering module opens to introduce reducing agent into the exhaust system. The controller can activate the pump to compensate for the pressure drop and maintain the pressure as close as possible to the set pressure by modifying a parameter affecting the pump's operation, such as increasing the pump speed or cycle rate. The pump may be a centrifugal or positive displacement pump driven by a motor or a solenoid.Modifying the parameter affecting pump operation to maintain set pressure provides an estimated flow recirculation based on system pressure and pump activation. This means that when the metering module is open and dosing, the pump speed increased to maintain set pressure can indicate the amount of reducing agent flowing through the system and being dosed. The controller can use the estimated flow recirculation information and a commanded dose to calculate a percentage error or ratio between the commanded flow to the metering module and the estimated flow recirculation to identify the diagnostic errors mentioned above. II. Overview of the post-treatment system

[0016] Fig. Figure 1 represents an aftertreatment system 100 with an exemplary feed system 110 for an exhaust system 190. The aftertreatment system 100 comprises a diesel particulate filter (DPF) 102, the reducing agent feed system 110, a decomposition chamber or decomposition reactor 104, and an SKR catalyst 106.

[0017] The DPF 102 is configured to remove particulate matter, such as soot, from the exhaust gas flowing into the exhaust system 190. The DPF 102 includes an inlet where the exhaust gas enters and an outlet where the exhaust gas exits after the particulate matter has been largely filtered out of the exhaust gas and / or converted into carbon dioxide.

[0018] The decomposition chamber 104 is configured to convert a reducing agent, such as urea, aqueous ammonia, or diesel exhaust fluid (DEF), into ammonia. The decomposition chamber 104 includes a reducing agent introduction system 110 with a metering module 112, which is configured to meter the reducing agent into the decomposition chamber 104. In some reactions, the urea, aqueous ammonia, or DEF is introduced upstream of the SKR catalyst 106. The reducing agent droplets then undergo evaporation, thermolysis, and hydrolysis processes to form gaseous ammonia within the exhaust system 190. The decomposition chamber 104 includes an inlet in fluid communication with the DPF 102 to allow the NO to be removed. x -to receive exhaust gas containing emissions, as well as an outlet for the exhaust gas, the NO x -Emissions, the ammonia and / or remaining reducing agent to flow to the SKR catalyst 106.

[0019] The decomposition chamber 104 includes the metering module 112, which is attached to the decomposition chamber 104 such that the metering module 112 can meter a reducing agent, such as urea, hydrated ammonia, or DEF, into the exhaust gases flowing into the exhaust system 190. The metering module 112 may include an insulator 114 located between a portion of the metering module 112 and the portion of the decomposition chamber 104 to which the metering module 112 is attached. The metering module 112 is fluidically coupled to one or more reducing agent sources 116. In some reactions, a pump 118 may be used to pressurize the reducing agent from the reducing agent source 116 for introduction into the metering module 112.

[0020] The dosing module 112 and the pump 118 are also electrically or communicatively coupled to a controller 120. The controller 120 is configured to control the dosing module 112 to dose reducing agent into the decomposition chamber 104. The controller 120 can also be configured to control the speed or cycle rate of the pump 118. The controller 120 can include a microprocessor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), etc., or combinations thereof. The controller 120 can include memory, including, but not limited to, electronic, optical, magnetic, or any other storage or transmission device capable of sending program instructions to a processor, ASIC, FPGA, etc.The memory can comprise a memory chip, electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), flash memory, or other suitable memory from which the controller can read 120 instructions. The instructions can comprise code written in any suitable programming language.

[0021] The controller 120 can be designed to perform certain operations described herein. In some implementations, the controller 120 forms part of a processing subsystem, including one or more computing devices with storage, processing, and / or communication hardware. The controller 120 can be a single device or a distributed system, and the functions of the controller can be performed by hardware and / or as computer instructions on a durable, computer-readable storage medium.

[0022] In some embodiments, the controller 120 includes one or more modules designed to functionally execute the operations of the controller 120. The description contained herein, including the modules, emphasizes the structural independence of the aspects of the controller 120 and illustrates a grouping of operations and tasks of the controller 120. Other controllers that perform similar operations are within the scope of this application. Modules may be implemented in hardware and / or as computer instructions on a durable, computer-readable storage medium, and modules may be distributed across different hardware or computer-based components. More specific descriptions of certain embodiments of control operations are provided in the [reference to be added]. Fig. 3. Includes a referenced section.

[0023] Exemplary and non-limiting module implementation elements include sensors providing any value specified herein, sensors providing a value that is a precursor to any value specified herein, data link and / or network hardware including communication chips, oscillating crystals, communication links, cables, twisted wiring, coaxial wiring, armored wiring, transmitters, receivers and / or transceivers, logic circuits, hard-wired logic circuits, reconfigurable logic circuits in a specified permanent state according to the module specification, any actuator including at least one electrical, hydraulic or pneumatic actuator, a solenoid, an operational amplifier, analog controls (springs, filters, integrators, adders, dividers, gain elements) and / or digital controls.

[0024] The SKR catalyst 106 is configured to reduce NO x -contributes to emissions by producing a NO x -Reduction process between ammonia and NO x The conversion of the exhaust gas into diatomic nitrogen, water and / or carbon dioxide is accelerated. The SKR catalyst 106 contains an inlet in flow communication with the decomposition chamber 104, through which exhaust gas and reducing agent enter, as well as an outlet in flow communication with one end of the exhaust system 190.

[0025] The exhaust system 190 can also include a diesel oxidation catalyst (DOC) in flow communication with the exhaust system 190 (for example, downstream of the SKR catalyst 106 or downstream of the DPF 102) to oxidize hydrocarbons and carbon monoxides in the exhaust gas. III. Exemplary diagnostic system

[0026] Fig. Figure 2 shows components of a diagnostic system 200 for diagnosing a post-treatment system with a reducing agent source 116, pump 118, dosing module 112, and controller 120. The diagnostic system 200 also includes a pressure sensor 210 for determining the pressure within a pressure line 212, which connects the pump 118 to the dosing module 112. In some implementations, a valve 220 can be provided to selectively connect a return line 222, which is in flow communication with the reducing agent source 116, to either the pump 118 and / or the dosing module 112.

[0027] Pump 118 is in flow communication with the reducing agent source 116 and is configured to receive reducing agent from the source 116 and to pump the reducing agent into pressure line 212. Pressure line 212 is in flow communication with the dosing module 112 and supplies the dosing module with pressurized reducing agent via pump 118. Pressure sensor 210 is connected to pressure line 212 and configured to determine the pressure of a liquid, such as the reducing agent, within pressure line 212. Pressure sensor 210 is configured to output data indicating the measured pressure.

[0028] The metering module 112 is configured to meter the reducing agent entering an exhaust system from the pressure line 212. The metering module 112 may include an injector that can be opened, closed, and / or partially opened to regulate the amount of reducing agent metered into the exhaust system. In some implementations, the metering module 112 meters reducing agent based on a specified dose amount determined by the controller 120. This means that the metering module 112 causes the injector to open, close, and / or partially open to meter the reducing agent, based on the instruction received from the controller 120 to meter a quantity of reducing agent for the specified dose amount.

[0029] In some implementations, the valve 220 is provided with a return line 222 for selective opening, closing, and / or partial opening to return reducing agent from the pressure line 212 to the reducing agent source 116. In some cases, the valve 220 may be a solenoid valve. In some implementations, the pump 118, the pressure sensor 210, and the valve 220 can be integrated into a pump assembly. Such a pump assembly may include additional components, such as various sensors (e.g., temperature, quality, level, etc.), a heater, etc.

[0030] The controller 120 communicates electrically with the pump 118, the pressure sensor 210, and the dosing module 112. The controller 120 can receive data from the pressure sensor 210 indicating the pressure of the reducing agent in the pressure line 212 between the pump 118 and the dosing module 112. The controller 120 is also configured to control the pump 118 by increasing, decreasing, or maintaining its speed, or by controlling other operational aspects of the pump 118, such as, but not limited to, operating it at partial or full stroke. The controller 120 is also configured to selectively control the dosing module 112 to introduce reducing agent into an exhaust system. In some implementations, the control unit 120 is also in electrical communication with the valve 220 in order to open, close and / or partially open the valve 220.

[0031] During operation, the controller 120 can activate the pump 118 to pump reducing agent from the reducing agent source 116 into the pressure line 212 until a pressure determined by the pressure sensor 210 substantially corresponds to the setpoint pressure. In some implementations, the controller can selectively control the pump 118 and / or the valve 220 to maintain the setpoint pressure. If the reducing agent is to be metered into an exhaust system, the controller 120 can selectively control the metering module 112 to meter the reducing agent into the exhaust system.

[0032] The controller 120 can issue an instruction signal to the dosing module 112 to regulate the dosing module 112. For example, the controller 120 can determine an instructed dosage quantity of reducing agent to be dispensed by the dosing module 112. Based on the instructed dosage quantity, the controller 120 can issue an instruction signal to the dosing module 112 to open, close, and / or partially open an injector of the dosing module 112 for dosing the reducing agent.

[0033] When the dosing module 112 opens or partially opens the injector, the pressure in the pressure line 212 drops. This pressure drop can be detected by the pressure sensor 210. In response to the pressure drop indicated by the pressure sensor 210, the controller 120 can modify a parameter affecting the operation of the pump 118, such as increasing the speed and / or cycle rate of the pump 118, and / or otherwise regulating the operation of the pump 118 to compensate for the pressure loss and / or to keep the pressure detected by the pressure sensor 210 as close as possible to the set pressure. Such a change in the operation of the pump 118 can be used to determine an estimated flow recirculation. This means that the increase, decrease, or lack thereof in the operation of the pump 118 when the dosing module 112 is activated for reducing agent dosing is indicative of the amount of reducing agent actually being dosed.

[0034] The controller 120 can use the specified dose and the estimated flow recirculation to determine the error between the specified dose and the estimated flow recirculation. In some reactions, the specified dose can be integrated for a predetermined limit volume of the specified reducing agent flow (e.g., 10 ml, 5 ml, etc.) to determine an integrated specified flow rate. A time period within which the specified dose reaches the predetermined limit volume can be defined and used to integrate the estimated flow recirculation to determine an integrated estimated flow recirculation. In other reactions, the specified dose can be integrated or summed over a time period to determine an integrated specified flow rate.Similarly, the estimated flow recirculation can be integrated or summed over a period of time to determine an integrated estimated flow recirculation. In some implementations, the period for the integrated instructed flow rate and the integrated estimated flow recirculation can be a predetermined time, such as 0.1 seconds, 1 second, 5 seconds, 10 seconds, 1 minute, etc. In other implementations, the period can be based on the instruction to the metering module 112 (e.g., the period can correspond to the time between the opening and closing of the injector of the metering module 112).

[0035] The controller 120 can determine a percentage error value based on the following equation: %Error = Integrated specified flow rate - Integrated estimated flow rate / Integrated specified flow rate × 100

[0036] The percentage error value can be used to diagnose errors such as a dosing module getting stuck in the open or closed state, a blockage or leak in the dosing module and / or pressure line and / or a line break.

[0037] For example, if the percentage error is positive (i.e., the integrated specified flow rate is greater than the integrated estimated flow return), then the percentage error value could indicate that an injector of the metering module 112 is stuck in the closed position, that an injector of the metering module 112 is blocked, and / or that there is a blockage in the pressure line 212. This means that the percentage error could indicate that less reducing agent is being metered than specified. In some implementations, the controller 120 can compare the determined percentage error value with one or more predetermined limits to determine which fault condition caused the error.If, for example, the percentage error value is greater than a first positive predetermined error limit, such as 90%, then the controller 120 can set an error flag or other indicator that an injector of the dosing module 112 is stuck in the closed position or that the pressure line 212 is blocked. If the percentage error value is greater than a second positive predetermined error limit, such as 30%, but at the same time less than the first positive predetermined error limit, such as 90%, then the controller 120 can set an error flag or other indicator that an injector of the dosing module 112 or the pressure line 212 is partially blocked. In response to the error flag, the controller 120 can activate an error display and / or send an error code to another system.

[0038] If the percentage error is negative (i.e., the integrated estimated flow recirculation is greater than the integrated specified flow rate), then the percentage error value could indicate that an injector of metering module 112 is stuck open, there is a leak in an injector of metering module 112 and / or in the pressure line 212, and / or the pressure line 212 is interrupted. This means that the percentage error could indicate that more reducing agent is being metered than specified. In some implementations, the controller 120 can compare the determined percentage error value with one or more predetermined limits to determine which fault condition caused the error.If, for example, the percentage error value is less than a first negative predetermined error limit, such as -90%, then the controller 120 can set an error flag or other indicator that an injector of the dosing module 112 is stuck open and / or the pressure line 212 is interrupted. If the percentage error value is greater than a second negative predetermined error limit, such as -30%, and also greater than the first negative predetermined error limit, such as -90%, then the controller 120 can set an error flag or other indicator that an injector of the dosing module 112 or the pressure line 212 has a leak. In response to the error flag, the controller 120 can activate an error display and / or send an error code to another system.

[0039] In some implementations, the controller can determine the percentage error a predetermined number of times before setting the error flag or another indicator. For example, the controller can determine the percentage error four times and set the error flag or another indicator if the percentage error indicates an error every four times.

[0040] Fig. Figure 3 shows an exemplary procedure 300 for determining a fault using a diagnostic system, such as the diagnostic system 200 from Fig. 2. Procedure 300 includes accessing instructed dosing quantity data (Block 302). The accessed instructed dosing quantity data can be stored in a memory, such as the memory of the controller 120 and / or another device. In some implementations, the instructed dosing quantity data can be temporarily stored and overwritten each time Procedure 300 is performed. The instructed dosing quantity data can be a table of instructed dosing quantities and a timestamp associated with each instructed dosing quantity.

[0041] Block 304 accesses the estimated flow feedback data. The accessed estimated flow feedback data can be stored in a memory, such as the memory of controller 120 and / or another device. In some implementations, the estimated flow feedback data can be temporarily stored and overwritten each time procedure 300 is performed. The estimated flow feedback data can be determined based on changes in pump operation, such as pump 118 in Fig. 2. This means that the estimated flow recirculation data can determine a reducing agent volume that is required due to changes in pump operation to maintain a target pressure within a pressure line, such as pressure line 212 in Fig. 2, was displaced. The estimated flow recirculation data can also be a table of the determined estimated flow recirculation data and a timestamp in conjunction with the respective determined estimated flow recirculation quantities.

[0042] Block 306 determines an integrated directed flow rate and an integrated estimated flow recirculation. The accessed directed flow rate data can be integrated for a predetermined limit volume of the directed reducing agent flow (e.g., 10 ml, 5 ml, etc.) to determine an integrated directed flow rate. A time period within which the directed flow rate reaches the predetermined limit volume can be defined and used to integrate the accessed estimated flow recirculation to determine an integrated estimated flow recirculation. In other implementations, the accessed directed flow rate data can be integrated or summed over a time period to determine an integrated directed flow rate.Similarly, the accessed estimated flow recirculation can be integrated or summed over a period of time to determine an integrated estimated flow recirculation. In some implementations, the period for the integrated instructed flow rate and the integrated estimated flow recirculation can be a predetermined time, such as 0.1 seconds, 1 second, 5 seconds, 10 seconds, 1 minute, etc. In other implementations, the period can be based on the instruction to the metering module 112 (e.g., the period can correspond to the time between the opening and closing of the injector of the metering module 112).

[0043] A percentage error can be determined based on the calculated, integrated directed flow rate and the integrated estimated flow recirculation (Block 308). A controller, such as Controller 120, can determine a percentage error value based on the following equation: %Error=Integrated specified flow rate−Integrated estimated flow rateIntegrated specified flow rate×100.

[0044] Block 310 determines whether the calculated percentage error is equal to or greater than a first predetermined positive limit (PET1), for example, 90%. If the calculated percentage error is equal to or greater than the first predetermined positive error limit, then an injector of the dosing module is stuck in the closed position or the pressure line is blocked (Block 312). An error flag or other indicator can be set based on the determined result that the dosing module injector is stuck in the closed position. In response to the determined result that the dosing module injector is stuck in the closed position or that a pressure line is blocked, a controller can activate an error indicator and / or send an error code to another system.

[0045] If the determined percentage error value is less than a first positive predetermined error limit, procedure 300 proceeds to determine whether the determined percentage error is equal to or greater than a second positive predetermined error limit (PET2), for example, 30% (Block 314). If the determined percentage error is equal to or greater than the second positive predetermined error limit, this indicates a partial blockage of a pressure line or injector of the metering module (Block 316). A fault flag or other indicator can be set based on the determined result that a partial blockage of the pressure line or injector of the metering module exists. In response to the determined result that the pressure line or injector of the metering module is partially blocked, a controller can activate a fault indicator and / or send a fault code to another system.

[0046] If the determined error value is less than the second positive predetermined error limit, it can be determined whether the determined percentage error is equal to or less than a first predetermined error limit (NET1), for example, -90% (Block 318). If the determined percentage error is equal to or less than the first negative predetermined error limit (i.e., the percentage error is -95%), then an injector of the metering module is stuck in the open position or a pressure line may be interrupted (Block 320). An error flag or other indicator can be set based on the determined result indicating that the injector of the metering module is stuck in the open position or that a pressure line may be interrupted.In response to the determined result, which indicates that the injector of the dosing module is stuck in the open position or that a pressure line may be interrupted, a control system can activate an error indicator and / or output an error code to another system.

[0047] If the determined percentage error value is greater than a first negative predetermined error limit (i.e., the percentage error is -70%), then procedure 300 proceeds to determine whether the determined percentage error is equal to or less than a second negative predetermined error limit (NET2), for example, -30% (Block 322). If the determined percentage error is equal to or less than the second negative predetermined error limit, this indicates a leak in the pressure line or in an injector of the metering module (Block 324). A fault flag or other indicator may be set based on the determined result indicating a leak in the pressure line or in an injector of the metering module.In response to the determined result, which indicates a leak in the pressure line or in an injector of the dosing module, a control system can activate an error display and / or output an error code to another system.

[0048] If the determined error value is greater than the second negative predetermined error limit, then procedure 300 can indicate acceptable operation (block 326) of the dosing system. This means that if the determined percentage error lies between the second positive predetermined error limit and the second negative predetermined error limit, the dosing system can be operated within acceptable limits. Procedure 300 can then either return to block 302 and / or terminate. The second positive predetermined error limit and the second negative predetermined error limit can be predetermined values ​​set based on acceptable operating conditions (e.g., 5% and -5%, 10% and -10%, 15% and -15%, 20% and -20%, 25% and -25%, etc.).

[0049] In some implementations, the specifications regarding error limits (blocks 310, 314, 318, 322) may be of a different order of magnitude. In some implementations, it may be possible to determine at the beginning whether the calculated percentage error is less than the second positive predetermined error limit and greater than the second negative predetermined error limit. If so, then procedure 300 can return to block 302 and / or terminate.

[0050] Fig. Figure 4 is a series of graphical representations of various values ​​for a specified dosing quantity, an estimated return flow, an integrated pump return flow, and a specified dosing flow, as well as a determined error percentage over a specific period for a functioning dosing module. The integrated pump return and specified flow values ​​are essentially the same, resulting in a percentage error value of approximately 1 and an error value of approximately 0%, respectively.

[0051] Fig. Figure 5 is a series of graphical representations of various values ​​for a commanded dosing quantity, an estimated return flow, an integrated pump return flow, and a commanded dosing flow, as well as a determined error percentage over a specific time period for a dosing module stuck in the closed state. The integrated pump return values ​​are essentially zero, while the commanded flow values ​​vary as a controller transmits command values ​​for reducing agent dosing to a dosing module. This results in a percentage error value that varies for values ​​above 1, resulting in a positive error value of approximately 100% and indicating a closed-stuck fault.

[0052] Fig. Figure 6 is a series of graphical representations of various values ​​for a commanded dosing quantity, an estimated return flow, an integrated pump return flow, and a commanded dosing flow, as well as a determined error percentage over a specific time period for a dosing module stuck in the open state. The integrated pump return values ​​increase significantly, while the commanded flow values ​​vary, as a controller transmits command values ​​for reducing agent dosing to a dosing module. This results in a percentage error value that varies for values ​​below 1, resulting in a negative error value and indicating an open-stuck fault.

[0053] Fig.Figure 7 is a series of graphical representations of various values ​​for a commanded dosing quantity, an estimated return flow, an integrated pump return flow, and a commanded dosing flow, as well as a determined error percentage over a specific time period for a closed-state dosing module that is reset to a normal operating state. The integrated pump return values ​​are initially essentially zero, while the commanded flow values ​​vary as a controller transmits command values ​​for reducing agent dosing to a dosing module. This results in a percentage error value that varies for values ​​above 1, resulting in a positive error value of approximately 100% and indicating a closed-state stuck fault. Later, the integrated pump return and commanded flow values ​​are essentially the same, resulting in a percentage error value of approximately 1 and 100%, respectively.This results in an error value of approximately 0% and allows us to conclude that normal operation has resumed.

[0054] While this specification contains many specific implementation details, these should not be considered limitations on the scope of the claims, but rather descriptions of features specific to certain implementations. Some features described in this specification in the context of separate implementations may also be implemented in combination in a single implementation. Conversely, different features described in the context of a single implementation may also be implemented separately in different implementations or in any suitable subcombination. Moreover, even if features are described above as acting in certain combinations and are themselves initially claimed as such, one or more features of a claimed combination may, in some cases, be omitted from the combination, and the claimed combination may be subject to a subcombination or a variation of a subcombination.

[0055] As used herein, the terms “essentially”, “circa”, and similar expressions have a broad meaning in accordance with their usual and accepted use among those skilled in the art, to whom the subject matter of this disclosure is addressed. Those skilled in the art reading this disclosure will understand that these terms serve to enable a description of certain described and claimed features without limiting the scope of these features to the precise numerical range set forth, unless otherwise indicated. Accordingly, these terms should be interpreted to mean that inessential or irrelevant modifications or changes to the described and claimed subject matter are within the scope of the invention as set forth in the appended claims.Furthermore, it should be noted that limitations in the claims should not be interpreted as "means plus function" limitations under US patent law if the term "means" is not used herein.

[0056] The terms "coupled," "connected," and similar terms, as used here, mean the direct or indirect joining of two components. Such joining can be stationary (e.g., permanent) or movable (e.g., removable or detachable). This joining can be achieved by integrally forming the two components, or the two components and additional intermediate components, as a single, connected body, either together, or by joining two components or the two components and additional intermediate components together.

[0057] The terms "flow-coupled," "in flow communication," and similar terms, as used here, refer to a situation where two components or objects have a path formed between them in which a fluid, such as water, air, a gaseous reducing agent, gaseous ammonia, etc., can flow, either with or without intervening components or objects. Examples of flow couplings or configurations enabling flow communication include pipes, channels, or any other suitable components that allow a fluid to flow from one component or object to another.

[0058] It is important to note that the structure and arrangement of the various exemplary implementations are purely illustrative and in no way restrictive. All changes and modifications that fall within the scope and / or application of the described implementations are to be protected. It is understood that certain features may not be necessary and implementations lacking various features may fall within the scope defined by the following claims. When reading the claims, it should be noted that words such as "a," "an," "at least one," or "at least one part" are not used with the intention of limiting the claim to only one thing, unless expressly stated so in the claim in question.When expressions such as "at least a part" and / or "a part" are used, the item in question may relate to a part and / or the entire item, unless expressly stated otherwise.

Claims

[1] Method for diagnosing a reducing agent dosing system (200), comprising: Accessing required dosage data; Accessing estimated flow feedback data, wherein the estimated flow feedback data is based on a parameter that affects the operation of a pump (118) of the metering system; Determine, using a controller (120), an integrated instructed flow rate based on the instructed metering flow rate data and an integrated estimated flow feedback based on the estimated flow feedback; Determine, using the control, a percentage error value in response to and using the integrated directed flow rate and the integrated estimated flow recirculation; Determining, using the control system, an error based on the determined percentage error value and one or more predetermined error limits, wherein the determination has: Determine that the error is a closed-stuck error if the determined percentage error value is equal to or greater than a first predetermined error limit; Determine that the fault is a partial blockage of the pressure line (212) or an injector fault if the determined percentage fault value is equal to or greater than a second predetermined fault limit; Determine that the fault is an open-stuck fault or a fault in a broken pressure line (212) if the determined percentage fault value is equal to or less than a third predetermined fault limit; and Determine that the fault is a leak in the pressure line (212) or an injector fault if the determined percentage fault value is equal to or less than a fourth predetermined fault limit; and Display the detected error. [2] Method according to claim 1, wherein the parameter represents a speed or number of cycles of the pump (118), and / or wherein the parameter affecting the operation of the pump is modified to maintain a target pressure in a pressure line (212) to a metering module (112). [3] Method according to claim 1 or 2, wherein the closed-stuck fault and the fault consisting of the partial blockage of a pressure line (212) or an injector are determined on the basis of a positive value of the percentage fault value, in particular, where the first limit is 90% and the second limit is 30%, and / or wherein the open-stuck fault, a fault consisting of an interrupted pressure line (212), and the fault consisting of a leak in a pressure line or injector are determined based on a negative value of the percentage fault value, in particular, where the third limit is -90% and the third limit is -30%. [4] System (200), comprising: a pump (118); a dosing module (112); and a controller (120) in electrical connection with the pump and the dosing module, wherein the controller is configured as follows: for outputting a reducing agent pump parameter to control pump operation, for outputting a metering flow parameter to regulate the amount of reducing agent dosed by the metering module, to access metering flow quantity data based on metering flow parameters output to the metering module, to access estimated reduction backflow guidance data based on reduction pump parameters output to the reduction pump, to determine an integrated directed flow rate based on the metering flow rate data and an estimated flow recirculation based on the estimated flow recirculation, to determine a percentage error value in response to and using the integrated instructed flow rate and the integrated estimated flow recirculation, to determine an error based on the determined percentage error value and one or more predetermined error limits, wherein the determination includes: Determine that the error is a closed-stuck error if the determined percentage error value is equal to or greater than a first predetermined error limit; Determine that the fault is a partial blockage of the pressure line (212) or an injector fault if the determined percentage fault value is equal to or greater than a second predetermined fault limit; Determine that the fault is an open-ended fault or a fault in a broken pressure line if the determined percentage fault value is equal to or less than a third predetermined fault limit; and Determine that the fault is a leak in the pressure line or an injector fault if the determined percentage fault value is equal to or less than a fourth predetermined fault limit, and to display a message indicating the detected error. [5] System according to claim 4, further comprising: a pressure sensor (210) configured to measure the pressure of a reducing agent supplied to the dosing module (112) by the pump (118), wherein the controller (120) is also configured to output the reducing agent pump parameters based on data indicating a pressure measured by the pressure sensor, preferably, wherein the control is also configured to output the reducing agent pump parameter based on a setpoint pressure to be maintained in a pressure line (212) to the dosing module, in particular, wherein the reducing agent pump parameters include a parameter indicating a speed or the number of cycles of the pump. [6] System according to claim 4 or 5, wherein the closed-stuck fault and the fault consisting of the partial blockage of a pressure line (212) or an injector are determined based on a positive value of the percentage fault value, in particular, where the first limit is 90% and the second limit is 30% and / or wherein the open-stuck fault, the fault existing in an interrupted pressure line (212) and the fault existing in a leak in a pressure line or injector are determined on the basis of a negative value of the percent fault value, in particular wherein the third limit is -90% and the fourth limit is -30%. [7] Device comprising a controller (120) communicating with a pump (118) and a dosing module (112), wherein the controller is configured as follows: for outputting a reducing agent pump parameter to control pump operation; for outputting a metering flow parameter to regulate the amount of reducing agent dosed by the metering module; to access dosing flow quantity data based on dosing parameters output to the dosing module; to access estimated reduction flow recirculation data based on reduction pump parameters output to the reduction pump; to determine an integrated directed flow rate based on the metering flow rate data and an estimated flow recirculation based on the estimated flow recirculation; to determine a percentage error value in response to and using the integrated directed flow rate and the integrated estimated flow recirculation; to determine an error based on the determined percentage error value and one or more predetermined error limits, wherein the determination includes: Determine that the error is a closed-stuck error if the determined percentage error value is equal to or greater than a first predetermined error limit; Determine that the fault is a partial blockage of the pressure line (212) or an injector fault if the determined percentage fault value is equal to or greater than a second predetermined fault limit; Determine that the fault is an open-stuck fault or a fault in a broken pressure line (212) if the determined percentage fault value is equal to or less than a third predetermined fault limit; and Determine that the fault is a leak in the pressure line (212) or an injector fault if the determined percentage fault value is equal to or less than a fourth predetermined fault limit, and to display a message indicating the detected error. [8] Device according to claim 7, wherein the reducing agent pump parameters include a parameter indicating a speed or number of cycles of the pump (118). [9] Device according to claim 7 or 8, wherein the closed-stuck fault and the fault consisting of the partial blockage of a pressure line (212) or an injector are determined based on a positive value of the percentage fault value, in particular, where the first limit is 90% and the second limit is 30%, and / or wherein the open-stuck fault, a fault existing in an interrupted pressure line (212), and the fault existing in a leak in a pressure line or injector are determined based on a negative value of the percentage fault value, in particular, where the third limit is -90% and a fourth limit is -30%.

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