Patent Description:
Emissions regulations for internal combustion engines have become more stringent over recent years. Environmental concerns have motivated the implementation of stricter emission requirements for internal combustion engines throughout much of the world. Governmental agencies, such as the Environmental Protection Agency (EPA) in the United States, carefully monitor the emission quality of engines and set emission standards to which engines must comply. Consequently, the use of exhaust aftertreatment systems on engines to reduce emissions is increasing.

Exhaust aftertreatment systems are generally designed to reduce emission of particulate matter, nitrogen oxides (NOx), hydrocarbons, and other environmentally harmful pollutants. However, the components that make up the exhaust aftertreatment system can be susceptible to failure and degradation. Because the failure or degradation of components may have adverse consequences on performance and the emission-reduction capability of the exhaust aftertreatment system, the detection and, if possible, correction of failed or degraded components is desirable.

<CIT> discloses an internal combustion engine operating at a lean air/fuel ratio, which includes a reductant injection system configured to dispense reductant into an exhaust gas feedstream upstream of a selective catalytic reduction device. The reductant injection system includes a reductant delivery system fluidly coupled to a reductant dispensing device that is configured to dispense the reductant. A method for monitoring the reductant injection system includes commanding the reductant dispensing device to dispense reductant at a prescribed reductant flowrate, controlling the reductant delivery system to a preferred operating state, monitoring operation of the reductant delivery system and estimating a reductant flowrate as a function of the monitored operation of the reductant delivery system, and diagnosing operation of the reductant injection system as a function of the prescribed reductant flowrate and the estimated reductant flowrate.

<CIT> discloses a reducing agent supply apparatus abnormality diagnosis unit which includes: a reducing agent injection valve controller for determining an energization on/off duty ratio according to an instructed injection amount of the reducing agent to issue an instruction for driving the reducing agent injection valve; a pump controller for determining an energization on/off duty ratio to issue an instruction for driving the pump so that the pressure in the reducing agent passage is maintained at a predetermined system pressure, based on the difference between the detected pressure in the reducing agent passage and the system pressure; and an abnormality determiner for performing abnormality determination of the reducing agent supply apparatus based on the duty ratio of the reducing agent injection valve and the duty ratio of the pump in a predetermined period.

<CIT> discloses a method for operating a metering device for a liquid additive which includes providing the metering device with at least one pump having a movable pump element carrying out pumping movements to pump the liquid additive and at least one injector connected through a pressure line to a pressure side of the pump and being opened to meter the liquid additive. The injector is opened in a step a). In a step b), the liquid additive is then metered and the pumping movements are counted during metering. In a step c), the injector is then closed. In a step d), the number of pumping movements ascertained in step b) are then compared with the opening time of the injector between step a) and step c) in order to carry out a diagnosis of the operation of the metering device. A metering device and a motor vehicle are also provided.

<CIT> discloses a system for diagnosing and/or determining the performance of a reductant delivery system which may include determining a flow rate offset value for the reductant delivery system. A reduced reductant flow rate may be determined for a reductant dosing command value based, at least in part, on the determined flow rate offset when reductant dosing command is non-zero. A reductant flow rate error can be determined based, at least in part, on a difference between an expected reductant flow rate value corresponding to the reductant dosing command value and the determined reduced reductant flow rate. A performance status value indicative of a performance status of the reductant delivery system may be outputted based, at least in part, on the determined first reductant flow rate error and a predetermined threshold.

<CIT> discloses a method for detecting whether an injector with a valve controlled by a PWM signal of an SCR system is at least partially clogged, said system comprising a pump, preferably a positive-displacement pump, driven by a motor and the pressure of which is controlled by a controller that continuously measures the pressure and/or another parameter characteristic of the energy transmitted by the motor to the pump, according to which, during normal operation of the SCR system, specific portions of one of these measurements are compared with equivalent portions stored in a memory.

<CIT> discloses a method for diagnosing a metering valve for metering a reagent into the exhaust gas region of an internal combustion engine. The metering valve is actuated by a pulse-width-modulated metering valve actuation signal with a certain duty factor for setting the metering rate. A reagent pump places the reagent at a reagent pressure, and the reagent pump is operated with a pulse-width-modulated pump actuation signal with a certain duty factor. Diagnosis of the metering valve is carried out on the basis of an evaluation of the increase in the metering valve actuation signal pulse duty factor after a predefined increase in the metering rate. The reagent filling level of an SCR catalytic converter arranged in the exhaust gas region is taken into account. At the start of the diagnosis, the reagent storage capacity of the SCR catalytic converter is checked.

One embodiment relates to an apparatus. The apparatus includes a pump, a delivery mechanism in fluid communication with the pump, and a controller communicatively coupled to the pump and the delivery mechanism. The controller is structured to interpret, via a pump diagnostic circuit, first and second pump parameters indicative of first and second pump rates, interpret, via a dosing diagnostic circuit, first and second dosing parameters indicative of at least one of (i) first and second reductant flows or (ii) first and second injector characteristics, determine, via a delivery diagnostic circuit, a delivery status based, at least in part, on the interpretation of the first and second pump parameters and the first and second dosing parameters, and generate, via the delivery diagnostic circuit, a status command indicative at least one of an under-restricted delivery mechanism or an over-restricted delivery mechanism in response to the determination of the delivery status.

These and other features, together with the organization and manner of operation thereof, will become apparent from the following detailed description when taken in conjunction with the accompanying drawings.

Following below is a detailed description of various concepts related to, and implementations of, methods, apparatuses, and systems for determining reductant delivery performance. The various concepts introduced above and discussed in greater detail below may be implemented in any of numerous ways, as the described concepts are not limited to any particular manner of implementation. Examples of specific implementations and applications are provided primarily for illustrative purposes.

Referring to the Figures generally, the various embodiments disclosed herein relate to a system and method for determining reductant delivery performance. According to the present disclosure, a controller interprets first and second pump parameters indicative of first and second pump rates, interprets first and second dosing parameters indicative of first and second reductant flows, determines a delivery status based, at least in part, on the interpretation of the first and second pump parameters and the first and second dosing parameters, and generates a status command indicative at least one of an under-restricted delivery mechanism or an over-restricted delivery mechanism in response to the determination of the delivery status. As used herein, "pump parameters" refer to characteristics, data, or information relating to operation of the pump. Accordingly, pump parameters may include, but are not limited to, information indicative of a speed of the pump, a flow rate of DEF through the pump, an on-time of the pump (e.g., when the pump is turned on, how long the pump is turned on, etc.), and any other information that may be used to ascertain, observe, or otherwise monitor operation of the pump.

Conventional systems that estimate or determine reductant delivery performance utilize non-intrusive approaches, such as comparing an estimated system parameter to a measured system parameter. Conventional systems have also utilized intrusive approaches, such as temporarily disabling the closed-loop control and operating in open-loop mode or performing signal processing at a high dosing command. However, these approaches tend to be very sensitive to the vehicle operation cycle and do not reliably exhibit the desired diagnostic separation between healthy and failed systems.

Generally speaking, these conventional systems fail to be robust to all of the variation in vehicle operation cycle, installation, and part manufacturing tolerances. As a result, these diagnostic systems tend to be inaccurate at determining reductant delivery performance. As described more fully herein, Applicants have developed a system, method, and apparatus for determining reductant delivery performance by utilizing signal processing to interpret various pump parameters and dosing parameters (e.g., Injection On Time) at a plurality of predetermined positions. In contrast and in another embodiment, an intrusive diagnostic test may be performed. As used herein, the term "intrusive" (in regard to performing one or more diagnostic tests) is used to refer to an active diagnostic test. In other words, an intrusive method, system, and apparatus describe a diagnostic test or protocol that is forced to run on the engine and exhaust aftertreatment system (i.e., causes the engine to operate at a certain speed, etc.). An intrusive diagnostic test may manipulate or excite the NOx emissions in the exhaust gas emitted from the engine system. In this regard, an "intrusive diagnostic test" may include overriding various set engine operating points to perform the diagnostic test. For example, many engine operating points are set to be in compliance with one or more vehicular laws (e.g., emissions, etc.). In some embodiments, overriding one or more of these operating points may force the engine into non-compliance with one or more vehicular laws. In such embodiments, the active or intrusive diagnostic test is often run in a service bay, test center environment, or other controlled environment.

Through experimentation, Applicants have discovered that the use of pump parameters (e.g., pump motor speed) and dosing parameters (e.g., DEF flow, reductant flow, etc.) provides a relatively more accurate determination of reductant delivery performance over conventional systems and methods. Technically and advantageously, a result of the present disclosure is an increased level of control over one or more components in an exhaust aftertreatment system. For example, when the reductant delivery performance is inaccurately determined, a delivery mechanism (e.g., a fuel injector or doser) may under dose or overdose effectively failing to meet the requirements mandated by regulatory agencies. This incorrect injection amount may cause incorrect OBD fault triggers for other diagnostics, poor diagnostics of reductant delivery performance, potentially unnecessary service on the aftertreatment system, increased warranty costs, and increased service time. Accordingly and advantageously, the system and method of the present disclosure may reduce warranty costs and service timing, provide relatively accurate reductant delivery performance determinations in both steady state and transient engine cycles, and facilitate an increased level of control over various aftertreatment components (e.g., a DEF injector, etc.). These and other features of the present disclosure are more fully explained herein.

Referring now to <FIG>, an engine exhaust aftertreatment system with a controller is shown, according to an example embodiment. It should be understood that the schematic depicted in <FIG> is but one implementation of an engine exhaust aftertreatment system. Many different configurations may be implemented that utilize the systems and methods described herein. Accordingly, while the system and method described herein are primarily directed to the diesel or compression-ignitionengine exhaust aftertreatment system depicted in <FIG>, it should be understood that the system and method of the present disclosure may be used in a various exhaust aftertreatment system configurations, such that the embodiment depicted in <FIG> is not meant to be limiting.

As shown in <FIG>, the engine system <NUM> includes an internal combustion engine <NUM> and an exhaust aftertreatment system <NUM> in exhaust gas-receiving communication with the engine <NUM>. Within the internal combustion engine <NUM>, air from the atmosphere is combined with fuel, and combusted, to power the engine. Combustion of the fuel and air in the compression chambers of the engine <NUM> produces exhaust gas that is operatively vented to an exhaust manifold and to the exhaust aftertreatment system <NUM>.

NOx (nitrogen oxides including NO and NO<NUM>) is a byproduct of combustion. The emission of NOx from an engine may be undesirable due to NOx (along with other compounds) having the ability to form smog, acid rain, and other types of pollution. The formation of NOx may be described in regard to the Zeldovich Mechanism (equations (<NUM>)-(<NUM>)):.

Equations (<NUM>)-(<NUM>) are reversible and refer to the Zeldovich Mechanism that describes how NOx may be formed.

In the example depicted, the exhaust aftertreatment system <NUM> includes a diesel particulate filter (DPF) <NUM>, a diesel oxidation catalyst (DOC) <NUM>, a selective catalytic reduction (SCR) system <NUM> with a SCR catalyst <NUM>, and an ammonia oxidation (AMOx) catalyst <NUM>. The SCR system <NUM> further includes a reductant delivery system that has a diesel exhaust fluid (DEF) source <NUM> that supplies DEF to a DEF doser <NUM> via a DEF line <NUM>. In an exhaust flow direction, as indicated by directional arrow <NUM>, exhaust gas flows from the engine <NUM> into inlet piping <NUM> of the exhaust aftertreatment system <NUM>. From the inlet piping <NUM>, the exhaust gas flows into the DOC <NUM> and exits the DOC into a first section of exhaust piping 28A. From the first section of exhaust piping 28A, the exhaust gas flows into the DPF <NUM> and exits the DPF into a second section of exhaust piping 28B. From the second section of exhaust piping 28B, the exhaust gas flows into the SCR catalyst <NUM> and exits the SCR catalyst into the third section of exhaust piping 28C. As the exhaust gas flows through the second section of exhaust piping 28B, it is periodically dosed with DEF by the DEF doser <NUM>. Accordingly, the second section of exhaust piping 28B acts as a decomposition chamber or tube to facilitate the decomposition of the DEF to ammonia. From the third section of exhaust piping 28C, the exhaust gas flows into the AMOx catalyst <NUM> and exits the AMOx catalyst into outlet piping <NUM> before the exhaust gas is expelled from the exhaust aftertreatment system <NUM>. Based on the foregoing, in the illustrated embodiment, the DOC <NUM> is positioned upstream of the DPF <NUM> and the SCR catalyst <NUM>, and the SCR catalyst <NUM> is positioned downstream of the DPF <NUM> and upstream of the AMOX catalyst <NUM>. However, in alternative embodiments, other arrangements of the components of the exhaust aftertreatment system <NUM> are also possible.

The DOC <NUM> may have any of various flow-through designs. Generally, the DOC <NUM> is structured to oxidize at least some particulate matter, e.g., the soluble organic fraction of soot, in the exhaust and reduce unburned hydrocarbons and CO in the exhaust to less environmentally harmful compounds. For example, the DOC <NUM> may be structured to reduce the hydrocarbon and CO concentrations in the exhaust to meet the requisite emissions standards for those components of the exhaust gas. An indirect consequence of the oxidation capabilities of the DOC <NUM> is the ability of the DOC to oxidize NO into NO<NUM>. In addition to treating the hydrocarbon and CO concentrations in the exhaust gas, the DOC <NUM> may also be used in the controlled regeneration of the DPF <NUM>, SCR catalyst <NUM>, and AMOx catalyst <NUM>. This may be accomplished through the injection, or dosing, of unburned HC into the exhaust gas upstream of the DOC <NUM>. Upon contact with the DOC <NUM>, the unburned HC undergoes an exothermic oxidation reaction which leads to an increase in the temperature of the exhaust gas exiting the DOC <NUM> and subsequently entering the DPF <NUM>, SCR catalyst <NUM>, and/or the AMOx catalyst <NUM>. The amount of unburned HC added to the exhaust gas is selected to achieve the desired temperature increase or target controlled regeneration temperature.

The DPF <NUM> may be any of various flow-through or wall-flow designs, and is structured to reduce particulate matter concentrations, e.g., soot and ash, in the exhaust gas to meet or substantially meet requisite emission standards. The DPF <NUM> captures particulate matter and other constituents, and thus may need to be periodically regenerated to burn off the captured constituents. Additionally, the DPF <NUM> may be configured to oxidize NO to form NO<NUM> independent of the DOC <NUM>.

As briefly described above, the SCR system <NUM> may include a reductant delivery system with a reductant (e.g., DEF) source <NUM>, a pump and a delivery mechanism or doser <NUM>. The reductant source <NUM> can be a container or tank capable of retaining a reductant, such as, for example, ammonia (NH<NUM>), DEF (e.g., urea), or hydrocarbons. The reductant source <NUM> is in reductant supplying communication with the pump, which is configured to pump reductant from the reductant source to the delivery mechanism <NUM> via a reductant delivery line <NUM>. The delivery mechanism <NUM> is positioned upstream of the SCR catalyst <NUM>. The delivery mechanism <NUM> is selectively controllable to inject reductant directly into the exhaust gas stream prior to entering the SCR catalyst <NUM>. The NOx in the exhaust gas stream includes NO<NUM> and NO. Generally, both NO<NUM> and NO are reduced to N<NUM> and H<NUM>O through various chemical reactions driven by the catalytic elements of the SCR catalyst in the presence of NH<NUM>. The SCR catalyst <NUM> may be any of various catalysts known in the art. For example, in some implementations, the SCR catalyst <NUM> is a vanadium-based catalyst, and in other implementations, the SCR catalyst is a zeolite-based catalyst, such as a Cu-Zeolite or a Fe-Zeolite catalyst.

The AMOx catalyst <NUM> may be any of various flow-through catalysts configured to react with ammonia to produce mainly nitrogen. As briefly described above, the AMOx catalyst <NUM> is structured to remove ammonia that has slipped through or exited the SCR catalyst <NUM> without reacting with NOx in the exhaust. In certain instances, the exhaust aftertreatment system <NUM> may be operable with or without an AMOx catalyst. Further, although the AMOx catalyst <NUM> is shown as a separate unit from the SCR catalyst <NUM> in <FIG>, in some implementations, the AMOx catalyst may be integrated with the SCR catalyst, e.g., the AMOx catalyst and the SCR catalyst can be located within the same housing. According to the present disclosure, the SCR catalyst and AMOx catalyst are positioned serially, with the SCR catalyst preceding the AMOx catalyst. In various other embodiments, the AMOx catalyst is not included in the exhaust aftertreatment system <NUM>. In these embodiments, the NOx sensor <NUM> may be excluded from the exhaust aftertreatment system <NUM> as well.

As shown, a plurality of sensors are included in the aftertreatment system <NUM>. The number, placement, and type of sensors included in the system <NUM> is shown for example purposes only. In other configurations, the number, placement, and type of sensors may differ. As shown, the system <NUM> includes NOx sensors <NUM>, <NUM>, <NUM>, <NUM> and temperature sensors <NUM>, <NUM>. The temperature sensors <NUM>, <NUM> are structured to acquire data indicative of a temperature at their locations. The NOx sensors <NUM>, <NUM>, <NUM>, and <NUM> are structured to acquire data indicative of a NOx amount at each location that the NOx sensor is located. The system <NUM> may include a NH<NUM> sensor and a particulate matter (PM) sensor (not shown). The NH<NUM> sensor is structured to acquire data indicative of a NH<NUM> amount in the SCR <NUM>. The PM sensor is structured to monitor particulate matter flowing through the exhaust aftertreatment system <NUM>. The controller <NUM> is communicably coupled to each of the sensors in the aftertreatment system <NUM>. Accordingly, the controller <NUM> is structured to receive data from one more of the sensors. The received data may be used by the controller <NUM> to control one more components in the aftertreatment system and/or for monitoring and diagnostic purposes.

As mentioned above, although the exhaust aftertreatment system <NUM> shown includes one of a DOC <NUM>, DPF <NUM>, SCR catalyst <NUM>, and AMOx catalyst <NUM> positioned in specific locations relative to each other along the exhaust flow path, in other embodiments, the exhaust aftertreatment system may include more than one of any of the various catalysts positioned in any of various positions relative to each other along the exhaust flow path as desired. Further, although the DOC <NUM> and AMOX catalyst <NUM> are non-selective catalysts, in some embodiments, the DOC and AMOX catalyst can be selective catalysts.

<FIG> is also shown to include an operator input/output (I/O) device <NUM>. The operator I/O device <NUM> is communicably coupled to the controller <NUM>, such that information may be exchanged between the controller <NUM> and the I/O device <NUM>, wherein the information may relate to one or more components of <FIG> or determinations (described below) of the controller <NUM>. The operator I/O device <NUM> enables an operator of the engine system <NUM> to communicate with the controller <NUM> and one or more components of the engine system <NUM> of <FIG>. For example, the operator input/output device <NUM> may include, but is not limited to, an interactive display, a touchscreen device, one or more buttons and switches, voice command receivers, etc. In various alternate embodiments, the controller <NUM> and components described herein may be implemented with non-vehicular applications (e.g., a power generator that utilizes an exhaust aftertreatment system having a reductant delivery sub-system). Accordingly, the I/O device may be specific to those applications. For example, in those instances, the I/O device may include a laptop computer, a tablet computer, a desktop computer, a phone, a wearable (e.g., a smart watch, smart optical wear, etc.), a personal digital assistant, etc..

The controller <NUM> may be structured to control or at least partly control the operation of the engine system <NUM> and associated sub-systems, such as the internal combustion engine <NUM> and the exhaust gas aftertreatment system <NUM> (and various components of each system such as the doser <NUM>). According to one embodiment, the components of <FIG> are embodied in a vehicle. In various alternate embodiments, as described above, the controller <NUM> may be used with any other engine-exhaust aftertreatment system (e.g., a power generator). The vehicle may include an on-road or an off-road vehicle including, but not limited to, line-haul trucks, midrange trucks (e.g., pick-up trucks), tanks, airplanes, and any other type of vehicle that utilizes an exhaust aftertreatment system. Communication between and among the components may be via any number of wired or wireless connections. For example, a wired connection may include a serial cable, a fiber optic cable, a CAT5 cable, or any other form of wired connection. In comparison, a wireless connection may include the Internet, Wi-Fi, Bluetooth, cellular, radio, 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 <NUM> is communicably coupled to the systems and components of <FIG>, the controller <NUM> is structured to receive data from one or more of the components shown in <FIG>. The structure and function of the controller <NUM> is further described in regard to <FIG>.

Referring now to <FIG>, a schematic diagram of a reductant delivery system <NUM> for an engine is shown, according to an example embodiment. As shown, the reductant delivery system <NUM> is a part of the system <NUM> of <FIG>. Accordingly, the reductant delivery system <NUM> may include a pump <NUM> and a delivery mechanism <NUM> (e.g., an injector or doser). As depicted, the delivery mechanism <NUM> is in fluid communication with the pump <NUM>. The pump <NUM> is structured to pump reductant (e.g., urea) from the reductant source <NUM> (e.g., a tank comprising urea) to the delivery mechanism <NUM> (e.g., a fuel injector). In some embodiments, the pump <NUM> as depicted is structured to maintain a minimum pressure within the delivery mechanism <NUM>. For example, when the delivery mechanism <NUM> is in a closed position (e.g., the delivery mechanism is not dosing), the pump <NUM> is structured to recirculate the DEF via a channel <NUM> (e.g., a supply line). In other embodiments, the pump <NUM> is further structured to maintain a predetermined pressure (e.g., <NUM> kPa) within the delivery mechanism <NUM> (e.g., within the injector nozzle). In alternative embodiments when the delivery mechanism <NUM> is in an open position (e.g., the delivery mechanism is dosing DEF), the pump <NUM> may be further structured to maintain the predetermined pressure (e.g., <NUM> kPa). To that end, the pump <NUM> may be structured to circulate the DEF as indicated by directional arrow <NUM>, <NUM>.

The reductant delivery system <NUM> also includes the controller <NUM> which is communicatively coupled to the pump <NUM> and the delivery mechanism <NUM>. In some embodiments, the controller <NUM> is structured to receive data provided by each of the pump <NUM> and the delivery mechanism <NUM>, wherein the received data may include, but is not limited to, pump command, pump motor speed, injector ontime, reductant flow rate, commanded reductant flow rate, exhaust gas temperature, exhaust flow rate, and reductant pressure. The received data may be used by the controller <NUM> to control one more components in the aftertreatment system and/or for monitoring and diagnostic purposes. To that end, the controller <NUM> may be structured, in some embodiments, to correlate and/or utilize the relationship between pump parameters (e.g., pump motor speed) and dosing parameters (e.g., DEF flow command or injector OnTime) as described herein with reference to <FIG>. Accordingly, Applicants have discovered that the use of pump parameters (e.g., pump motor speed or pump motor speed command) and dosing parameters (e.g., DEF flow command or injector OnTime) facilitates a relatively more accurate determination of reductant delivery performance.

With the above description in mind, referring now to <FIG>, an example structure for the controller <NUM> is shown according to one embodiment. As shown, the controller <NUM> includes a processing circuit <NUM> including a processor <NUM> and a memory <NUM>. The processor <NUM> may be implemented as a general-purpose processor, an application specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGAs), a digital signal processor (DSP), a group of processing components, or other suitable electronic processing components. The one or more memory devices <NUM> (e.g., RAM, ROM, Flash Memory, hard disk storage, etc.) may store data and/or computer code for facilitating the various processes described herein. Thus, the one or more memory devices <NUM> may be communicably connected to the processor <NUM> and provide computer code or instructions to the processor <NUM> for executing the processes described in regard to the controller <NUM> herein. Moreover, the one or more memory devices <NUM> may be or include tangible, non-transient volatile memory or non-volatile memory. Accordingly, the one or more memory devices <NUM> may 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.

The memory <NUM> is shown to include various circuits for completing at least some of the activities described herein. More particularly, the memory <NUM> includes circuits structured to facilitate the determination of reductant delivery performance. While various circuits with particular functionality are shown in <FIG>, it should be understood that the controller <NUM> and memory <NUM> may include any number of circuits for completing the functions described herein. For example, the activities of multiple circuits may be combined as a single circuit, additional circuits with additional functionality may be included, etc. Further, it should be understood that the controller <NUM> may control other activity beyond the scope of the present disclosure, such as the control of other vehicle systems. In this regard, the controller <NUM> may be embodied as an electronic control unit (ECU) included with a vehicle or included with an existing ECU, such as a transmission control unit and any other vehicle control unit (e.g., exhaust aftertreatment control unit, powertrain control circuit, engine control circuit, etc.). All such structural configurations of the controller <NUM> are intended to fall within the spirit and scope of the present disclosure.

Certain operations of the controller <NUM> described herein include operations to interpret and/or to determine one or more parameters. Interpreting or determining, as utilized herein, includes receiving values by any method known in the art, including at least receiving values from a datalink or network communication, receiving an electronic signal (e.g. a voltage, frequency, current, or PWM signal) indicative of the value, receiving a computer generated parameter indicative of the value, reading the value from a memory location on a non-transient computer readable storage medium, receiving the value as a run-time parameter by any means known in the art, and/or by receiving a value by which the interpreted parameter can be calculated, and/or by referencing a default value that is interpreted to be the parameter value.

As shown, the controller <NUM> includes a pump diagnostic circuit <NUM>, a dosing diagnostic circuit <NUM>, and a delivery diagnostic circuit <NUM>. The pump diagnostic circuit <NUM> is structured to interpret first and second pump parameters (e.g., pump speed command or duty cycle) indicative of first and second pump rates (e.g., actual pump speed). In some embodiments, the pump speed is approximately equal or proportional to the pump command at steady-state operation. Accordingly, the pump diagnostic circuit <NUM> is structured to correlate the first and second pump parameters to the first and second pump rates. In one embodiment, the pump diagnostic circuit <NUM> may include or be communicably coupled with an engine sensor such as an engine speed sensor for receiving a value indicative of the speed of the engine. In another embodiment, the pump diagnostic circuit <NUM> may include communication circuitry including, but not limited to, wired and wireless communication protocol to facilitate reception of a value indicative of the speed of the engine. In still another embodiment, the pump diagnostic circuit <NUM> may include machine-readable media stored by the memory and executable by the processor, wherein the machine-readable media facilitates performance of certain operations to receive a value of the speed of the engine. For example, the machine-readable media may provide an instruction (e.g., command, etc.) to an engine speed sensor operatively coupled to the engine to monitor and acquire data indicative of the speed of the engine. In this regard, the machine-readable media may include programmable logic that defines the frequency of acquisition of the engine speed data. In yet another embodiment, the pump diagnostic circuit <NUM> may include any combination of machine-readable content, communication circuitry, and the engine sensor. The first and second pump parameters may be stored in memory (e.g., the memory <NUM>) by the pump diagnostic circuit <NUM>. The pump diagnostic circuit <NUM> may utilize the processor <NUM> to perform the actions described herein. In some embodiments, the pump diagnostic circuit <NUM> is structured to provide the first and second pump parameters to the delivery diagnostic circuit <NUM>.

In some embodiments, the dosing diagnostic circuit <NUM> is structured to interpret first and second dosing parameters (e.g., injector OnTime) indicative of at least one of (i) first and second reductant flows or (ii) first and second injector characteristics. In one embodiment, the dosing diagnostic circuit <NUM> may include or be communicably coupled with an engine sensor such as an engine speed sensor for receiving a value indicative of the speed of the engine. In another embodiment, the dosing diagnostic circuit <NUM> may include communication circuitry including, but not limited to, wired and wireless communication protocol to facilitate reception of a value indicative of the speed of the engine. In still another embodiment, the dosing diagnostic circuit <NUM> may include machine-readable media stored by the memory and executable by the processor, wherein the machine-readable media facilitates performance of certain operations to receive a value of the speed of the engine. For example, the machine-readable media may provide an instruction (e.g., command, etc.) to an engine speed sensor operatively coupled to the engine to monitor and acquire data indicative of the speed of the engine. In this regard, the machine-readable media may include programmable logic that defines the frequency of acquisition of the engine speed data. In yet another embodiment, the pump dosing diagnostic circuit <NUM> may include any combination of machine-readable content, communication circuitry, and the engine speed sensor. The first and second reductant flows include the DEF flow corresponding to the pump <NUM>. In some embodiments, the DEF flow is approximately equal or proportional to the dosing parameters. Accordingly, the dosing diagnostic circuit <NUM> is structured to correlate the first and second reductant flows to the first and second dosing parameters. The first and second dosing parameters may be stored in memory (e.g., the memory <NUM>) by the dosing diagnostic circuit <NUM>. The dosing diagnostic circuit <NUM> may utilize the processor <NUM> to perform the actions described herein. As will be appreciated by one of ordinary skill in the art, the delivery mechanism <NUM> may demonstrate a direct relationship between the first and second reductant flows and the and first and second dosing parameters. The correlation of the reductant flow (e.g., DEF flow) to the dosing parameters (e.g., Injector OnTime) is described herein with reference to <FIG>. In further embodiments, the dosing diagnostic circuit <NUM> may be structured to provide the first and second dosing parameters to the delivery diagnostic circuit <NUM>.

In some embodiments, the delivery diagnostic circuit <NUM> is structured to determine a delivery status based, at least in part, on the interpretation of the first and second pump parameters and the first and second dosing parameters. In one embodiment, the delivery diagnostic circuit <NUM> may include communication circuitry including, but not limited to, wired and wireless communication protocols and/or machine-readable media stored by the memory and executable by the processor,. In yet another embodiment, the delivery diagnostic circuit <NUM> may include any combination of machine-readable content, communication circuitry, etc. In some embodiments, the delivery diagnostic circuit <NUM> may be structured to receive, via the pump diagnostic circuit <NUM>, the first and second pump parameters. Alternatively or additionally, the delivery diagnostic circuit <NUM> may be structured to obtain, via the processor <NUM>, the first and second pump parameters from the memory <NUM>.

In other embodiments, the delivery diagnostic circuit <NUM> may be structured to receive, via the dosing diagnostic circuit <NUM>, the first and second dosing parameters. Alternatively or additionally, the delivery diagnostic circuit <NUM> may be structured to obtain, via the processor <NUM>, the first and second dosing parameters from the memory <NUM>.

As will be appreciated, the pump parameters (e.g., the Pump Command (%)) and the dosing parameters (e.g., Injector OnTime) may be averaged over a calibratable time duration at a plurality of positions (e.g., at a first level and a second level). The delivery diagnostic circuit <NUM> may be structured to average the pump parameters and/or the dosing parameters at a predetermined pressure (e.g., while the pressure control is stable).

In further embodiments, the delivery diagnostic circuit <NUM> may be structured to determine a delivery status, wherein the delivery status is indicative of a diagnostic metric corresponding to at least one of the pump <NUM> and delivery mechanism <NUM> ). In one embodiment, the delivery status may be based on a difference of the first and second pump parameters and a difference of the first and second dosing parameters.

An example process that may be utilized by the delivery diagnostic circuit <NUM> to determine the delivery status is as follows: <MAT>.

The "OnTimeDL1" and "OnTimeDL2" refers to the reductant flows at a first position (e.g., at level <NUM>) and a second position (e.g., at level <NUM>). The first position may be indicative of a low injection OnTime and the second position may indicate a higher injection OnTime than the first position. The further apart the first position is with respect to the second position, the larger the separation between a properly functioning system (e.g., a stable system) and an improperly functioning system (e.g., an eroded and/or clogged system) as illustrated herein with reference to <FIG>. For a delivery mechanism (e.g., a reductant injector of the solenoid type), OnTime may be approximately proportional to the flow of reductant through the delivery mechanism. The respective positions correspond to predefined levels of reductant flow that may be commanded intrusively by the diagnostic or commanded by the controller <NUM>. The "ΔOnTime" refers to a change of the reductant flow and "ΔPmpCmd" refers to a change of the pump rate. As will be appreciated by one of ordinary skill in the art, the delivery status may also be determined by an inverse relationship, such as ΔPmpCmd / ΔOnTime. The delivery status may be stored in memory (e.g., the memory <NUM>) by the delivery diagnostic circuit <NUM>. The delivery diagnostic circuit <NUM> may utilize the processor <NUM> to perform the actions described herein.

In some embodiments, the delivery diagnostic circuit <NUM> may utilize the delivery status to determine the status of a delivery mechanism <NUM>. The delivery mechanism <NUM> may take the form of an over-restricted delivery mechanism (e.g., an at least partially blocked injector, slow-responding injector solenoid, blocked lines, defective pump, etc.) and/or an under-restricted delivery mechanism (e.g., an eroded injector, faulty injector solenoid, leaky lines, defective pump, etc.). The determination of an over-restricted delivery mechanism or an under-restricted delivery mechanism may include determining whether the delivery status exceeds a predetermined status. As will be appreciated, an over-restricted (e.g., the delivery status of the dosing parameter is above <NUM>) delivery mechanism may dose less than the desired quantity, while an under-restricted (e.g., the delivery status of the dosing parameter is below <NUM>) delivery mechanism may dose more than the desired quantity. For example, the delivery diagnostic circuit <NUM> may be structured to indicate an over-restricted delivery mechanism in response to the predetermined status exceeding the delivery status. In one example embodiment, the under-restricted delivery mechanism may result in a deviation from nominal by <NUM>%. In another example embodiment, the over-restricted delivery mechanism may result in a deviation from nominal by <NUM>%. In other example embodiments, the delivery diagnostic circuit <NUM> may be structured to indicate an under-restricted delivery mechanism in response to the delivery status exceeding the predetermined status. In further embodiments, the delivery mechanism <NUM> may take the form of an over-restricted delivery mechanism (e.g., an at least partially blocked injector) and an under-restricted delivery mechanism (e.g., a partially eroded injector). Further description is provided herein with reference to <FIG>, a plot illustrating the relationship between the dosing parameters and the delivery status corresponding to a delivery mechanism which is, for example, <NUM>% eroded (e.g., under-restricted) and <NUM>% blocked (e.g., over-restricted).

Furthermore, the delivery diagnostic circuit <NUM>, in some embodiments, is structured to generate a status command indicative of at least one of an under-restricted delivery mechanism or an over-restricted delivery mechanism in response to the determination of the delivery status. The status command may be generated when the delivery status indicates a value in the range of <NUM> to <NUM>. To that end, the delivery diagnostic circuit <NUM> may be structured to provide the status command to the operator I/O device <NUM> (e.g., an interactive display, a touchscreen device, one or more buttons and switches, voice command receivers) to communicate the status of the reductant delivery performance to an operator of the engine system <NUM>. Furthermore, the delivery diagnostic circuit <NUM>, in some embodiments, is structured to generate a status command indicative at least one of an under-restricted delivery mechanism or an over-restricted delivery mechanism in response to the determination of the delivery status. In some embodiments, the delivery diagnostic circuit <NUM> may be structured to adjust the first and second pump parameters or the first and second dosing parameters in response to the determination of the delivery status to stabilize the engine system <NUM>. The determination of an over-restricted or under-restricted condition may result in a command to change the engine operating characteristic.

Referring now to <FIG>, a graph illustrating reductant delivery performance is shown according to an example embodiment. In some embodiments, the reductant delivery performance is determined based, at least in part, on a plurality of positions (e.g., calibratable dosing levels such as a first level DL1 and a second level DL2). The delivery diagnostic circuit <NUM> as described herein with reference to <FIG> may be structured to analyze the first and second pump parameters (e.g., the Pump Command (%)) corresponding to the first and second positions. In further embodiments, the delivery diagnostic circuit <NUM> may be structured to correlate the first and second pump parameters to the first and second dosing parameters (e.g., Injector OnTime). The first and second dosing parameters may correspond to the first and second positions. For example, as illustrated in <FIG>, the first and second pump parameters (e.g., the first Pump Command (%) which is approximately <NUM>% at DL1 and the second Pump Command (%) which is approximately <NUM>% at DL2) are correlated to the first and second dosing parameters (e.g., the Injection OnTime at DL1 at <NUM>/s and Injection OnTime at DL2 at <NUM>/s). In turn, the delivery status is determined based, at least in part, on the interpretation of the first and second pump parameters and the first and second dosing parameters as described herein which, thereby, determines the reductant delivery performance.

Referring now to <FIG>, a plot illustrating the relationship between the dosing parameters and the delivery status is shown according to an example embodiment. As will be appreciated, the Inventors have determined that the difference (e.g., the delta) between the first and second dosing parameters provides an improved indication of reductant delivery performance when compared to the actual values corresponding to the first and second dosing parameters. For example, as depicted in <FIG>, the difference between the first and second dosing parameters, such as the Injector OnTime of <NUM>% and <NUM>%, yields a ΔOntime = <NUM>%. There is also a similar reductant delivery performance provided by the difference between the first and second dosing parameters, such as the Injector OnTime of <NUM>% and <NUM>%, which also yield a ΔOntime = <NUM>%. Furthermore, as the difference in the first and second dosing parameters (e.g., Injector OnTime (%) at DL1 and DL2) increases, the diagnostic separation improves. Alternatively or additionally, as the difference in the first and second dosing parameters (e.g., Injector OnTime (%) at DL1 and DL2) decreases, the diagnostic separation may be reduced. For example, utilizing the first and second dosing parameters (e.g., Injector OnTime of <NUM>% and <NUM>% which yields ΔOntime=<NUM>%) to determine a delivery status may result in a reduction of the diagnostic separation. As depicted, the error bar illustrates the mean and ±3σ deviation for the determination of the delivery status. The mean is illustrated by the square and the ±3σ deviation is shown by the errors bars. The general trend as illustrated is that the higher the ΔOnTime the larger the separation between the baseline and the ±<NUM>% delivery mechanism which is, for example, <NUM>% eroded (e.g., under-restricted) and <NUM>% blocked (e.g., over-restricted). When the ΔOntime ≥ <NUM>%, the diagnostic separation is within the ±3σ deviation band and results in a decreased chance of a false OBD response (e.g., activation of a false fault code, indicator lamp, or the like). When the ΔOntime < <NUM>%, there is diagnostic separation and an increased chance of a false OBD response.

Referring back to <FIG>, the delivery diagnostic circuit <NUM>, in further embodiments, may be structured to generate a stability command (e.g., a command generated in response to an OBD trigger configured to indicate fault or stability) based on the first and second dosing parameters (e.g., the commanded or actual OnTime or reductant flow). As will be appreciated, the Inventors have determined that the stability of the delivery mechanism <NUM> may be indicated by a correlation of the dosing parameters (e.g., the commanded or actual OnTime or reductant flow) and other system parameters or characteristics (e.g. the error in reductant pressure control, injector operation data, etc.). In some example embodiments, a properly functioning delivery mechanism <NUM> may be indicated when the dosing parameters (e.g., the commanded OnTime) correlate to (e.g., match, equate to, etc.) the dosing values (e.g., the actual OnTime). Accordingly, the delivery diagnostic circuit <NUM> may be structured to determine a plurality of predetermined threshold values, based, at least in part, on the first and second dosing parameters (e.g., the commanded OnTime at DL1 and DL2).

In some embodiments, the delivery diagnostic circuit <NUM> may be structured to determine whether the plurality of the predetermined threshold values exceeds a plurality of values corresponding to the first and second dosing parameters. In turn, the delivery diagnostic circuit <NUM> may be structured to generate the stability command in response to the plurality of predetermined threshold values exceeding the plurality of values corresponding to the first and second dosing parameters. In further embodiments, if the dosing parameters do not match the dosing values, the delivery diagnostic circuit may be structured to generate a stability command (e.g., a command generated in response to an OBD trigger configured to indicate fault).

In some embodiments, the delivery diagnostic circuit <NUM> may be structured to provide the stability command to the operator I/O device <NUM> (e.g., an interactive display, a touchscreen device, one or more buttons and switches, voice command receivers) to communicate the status of the reductant delivery performance to an operator of the engine system <NUM>. Alternatively or additionally, the stability command may be stored in memory (e.g., memory <NUM>) by the delivery diagnostic circuit <NUM>.

Referring now to <FIG>, a flowchart of a method of generating a status command indicative at least one of an under-restricted delivery mechanism or a over-restricted delivery mechanism is shown, according to one embodiment. According to one embodiment, method <NUM> represents a laboratory-based method (e.g., in a test engine set up). Based on the results of method <NUM>, the circuits in the controller <NUM> may be calibrated (e.g., the first and second pump parameters indicative of first and second pump rates reinterpreted, the first and second dosing parameters indicative of first and second reductant flows reinterpreted, the delivery status redetermined, etc.). According to another embodiment, method <NUM> may be implemented in a service tool utilized by a technician. In this regard, the technician may troubleshoot one or more of the circuits of the controller <NUM>. In still another embodiment, the method <NUM> may be embodied in the controller <NUM> such that the controller <NUM> may continuously experience process improvement and refinement for the generation of the status command indicative at least one of an under-restricted delivery mechanism or a over-restricted delivery mechanism. All such variations are intended to fall within the spirit and scope of the present disclosure.

At process <NUM>, first and second pump parameters indicative of first and second pump rates are interpreted. The first and second pump rates may include a pump speed. The first and second pump parameters may include a pump command. At steady-state operation (e.g., a state by which the properties, parameters, etc. of the system are consistent), the pump speed may be approximately equal or proportional to the pump command. Accordingly, the first and second pump parameters are correlated to the first and second pump rates. Responsive to the correlation of the pump parameters to the pump rates, the first and second pump parameters indicative of first and second pump rates are interpreted.

At process <NUM>, first and second dosing parameters indicative of at least one of (i) first and second reductant flows or (ii) first and second injector characteristics are interpreted. The first and second reductant flows may include the DEF flow, while the first and second injector characteristics may include the error in reductant pressure control, data, or information relating to operation of the injector, etc. The first and second dosing parameters may include one or more dosing values (e.g., OnTime commands). The DEF flow may be approximately equal to the dosing values. Accordingly, the first and second reductant flows are correlated to the first and second dosing parameters. Responsive to the correlation of the first and second reductant flows to the first and second dosing parameters, the first and second dosing parameters indicative of first and second reductant flows are interpreted.

At process <NUM>, the delivery status may be determined based, at least in part, on the interpretation of the first and second pump parameters and the first and second dosing parameters. The pump parameters and the dosing parameters may be averaged over a calibratable time duration at a plurality of positions (e.g., at a first level and a second level). The delivery status may be determined based on a difference of the first and second pump parameters and a difference of the first and second dosing parameters. Accordingly, the example process (<NUM>) may be utilized to determine the delivery status.

At process <NUM>, a status command indicative of an under-restricted delivery mechanism or an over-restricted delivery mechanism may be generated in response to the determination of the delivery status. In turn, the status command may be provided to the operator I/O device <NUM> (e.g., an interactive display) to communicate the status of the reductant delivery performance to an operator of the engine system <NUM>.

The schematic flow chart diagrams and method schematic diagrams described above are generally set forth as logical flow chart diagrams. As such, the depicted order and labeled steps are indicative of representative embodiments. Other steps, orderings and methods may be conceived that are equivalent in function, logic, or effect to one or more steps, or portions thereof, of the methods illustrated in the schematic diagrams.

Additionally, the format and symbols employed are provided to explain the logical steps of the schematic diagrams and are understood not to limit the scope of the methods illustrated by the diagrams. Although various arrow types and line types may be employed in the schematic diagrams, they are understood not to limit the scope of the corresponding methods. Indeed, some arrows or other connectors may be used to indicate only the logical flow of a method. For instance, an arrow may indicate a waiting or monitoring period of unspecified duration between enumerated steps of a depicted method. Additionally, the order in which a particular method occurs may or may not strictly adhere to the order of the corresponding steps shown. It will also be noted that each block of the block diagrams and/or flowchart diagrams, and combinations of blocks in the block diagrams and/or flowchart diagrams, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and program code.

Many of the functional units described in this specification have been labeled as circuits, in order to more particularly emphasize their implementation independence. For example, a circuit may be implemented as a hardware circuit comprising custom VLSI circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. A circuit may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like.

Circuits may also be implemented in machine-readable medium for execution by various types of processors. An identified circuit of executable code may, for instance, comprise one or more physical or logical blocks of computer instructions, which may, for instance, be organized as an object, procedure, or function. Nevertheless, the executables of an identified circuit need not be physically located together, but may comprise disparate instructions stored in different locations which, when joined logically together, comprise the circuit and achieve the stated purpose for the circuit.

Indeed, a circuit of computer readable program code may be a single instruction, or many instructions, and may even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data may be identified and illustrated herein within circuits, and may be embodied in any suitable form and organized within any suitable type of data structure. The operational data may be collected as a single data set, or may be distributed over different locations including over different storage devices, and may exist, at least partially, merely as electronic signals on a system or network. Where a circuit or portions of a circuit are implemented in machine-readable medium (or computer-readable medium), the computer readable program code may be stored and/or propagated on in one or more computer readable medium(s).

The computer readable medium may be a tangible computer readable storage medium storing the computer readable program code. The computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

More specific examples of the computer readable medium may include but are not limited to a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a portable compact disc read-only memory (CD-ROM), a digital versatile disc (DVD), an optical storage device, a magnetic storage device, a holographic storage medium, a micromechanical storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, and/or store computer readable program code for use by and/or in connection with an instruction execution system, apparatus, or device.

The computer readable medium may also be a computer readable signal medium. Such a propagated signal may take any of a variety of forms, including, but not limited to, electrical, electro-magnetic, magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport computer readable program code for use by or in connection with an instruction execution system, apparatus, or device. Computer readable program code embodied on a computer readable signal medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, Radio Frequency (RF), or the like, or any suitable combination of the foregoing.

In one embodiment, the computer readable medium may comprise a combination of one or more computer readable storage mediums and one or more computer readable signal mediums. For example, computer readable program code may be both propagated as an electro-magnetic signal through a fiber optic cable for execution by a processor and stored on RAM storage device for execution by the processor.

Computer readable program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The computer readable program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone computer-readable package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server.

Claim 1:
A reductant delivery system (<NUM>) comprising:
a pump (<NUM>);
an injector (<NUM>) in fluid communication with the pump (<NUM>); and
a controller (<NUM>) communicatively coupled to the pump (<NUM>) and the injector (<NUM>), the controller (<NUM>) structured to:
interpret, via a pump diagnostic circuit, first and second pump parameters indicative of first and second pump rates;
interpret, via a dosing diagnostic circuit, first and second dosing parameters indicative of first and second injector characteristics;
determine, via a delivery diagnostic circuit, a delivery status based, at least in part, on the interpretation of the first and second pump parameters and the first and second dosing parameters; and
generate a status command indicative of at least one of an under-restricted injector or an over-restricted injector in response to the determination of the delivery status.