Patent Publication Number: US-10774778-B2

Title: Hierarchical engine control systems and methods

Description:
RELATED APPLICATIONS 
     The present application is a national phase filing under 35 U.S.C. § 371 of International Application No. PCT/US2015/055452, titled “HIERARCHICAL ENGINE CONTROL SYSTEMS AND METHODS,” filed on Oct. 14, 2015, the entire disclosure of which being expressly incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates generally to internal combustion engines. In particular, the disclosure relates to controlling internal combustion engines with subsystems having different response times. 
     BACKGROUND 
     Engine systems including internal combustion engines are often required to meet performance in several areas. While delivering requested amounts of power, engines are also often required to operate efficiently in terms of resource consumption and meet low emission requirements, such as EPA Tier 4 Final requirements for smoke and NO X  emissions. These goals are often governed by trade-offs, such as targeting greater power delivery while also targeting less fuel consumption. Engine systems are often calibrated to manage the trade-offs to achieve the overall goals. 
     An engine system often includes one or more subsystems, such as a fuel subsystem, an air handling subsystem, and an aftertreatment subsystem. Integrated calibration utilizing complex modeling of the entire engine system with all subsystems is often performed in order to adequately capture behavior and interactions between subsystems, which contributes to long calibration cycles. Another factor contributing to long calibration cycles is that engine systems are often calibrated to meet performance requirements under varying conditions, such as steady state, multiple transient states, and all at various altitudes. With ever more demanding performance goals, there remains a continuing need to robustly and time-efficiently calibrate engine systems and to control engine systems in operation to provide power, minimize resource consumption, and meet emissions requirements. 
     SUMMARY 
     Certain aspects of the disclosure relate to a system comprising a fuel system having a first response time; an air handling system having a second response time, the second response time being slower than the first response time; an aftertreatment system having a third response time, the third response time being slower than the second response time; and a controller. 
     Some embodiments of the controller are configured to interpret a first basis variable set for the fuel system, a second basis variable set for the air handling system, and a third basis variable set for the aftertreatment system; determine a first reference value set in response to the first basis variable set within a first time period determined in response to the first response time; determine a second reference value set in response to the second basis variable set within a second time period determined in response to the second response time; determine a third reference value set in response to the third basis variable set within a third time period determined in response to the third response time; and provide one or more control commands to each of the fuel system, the air handling system, and the aftertreatment system in response to the first reference value set, the second reference value set, and the third reference value set, respectively. 
     Further embodiments of the controller are configured to interpret operational information. Additional embodiments of the controller are configured to iteratively modify at least one of the first reference value set, the second reference value set, and the third reference value set in response to the operational information. Various embodiments of the controller model the operational information at least one time step ahead and to further selectively modify at least one of the first reference value set, the second reference value set, and the third reference value set in response to the modeled operational information. 
     Some aspects of the disclosure relate to a controller comprising a system parameter definer structured to interpret an aftertreatment basis variable set, an air handling basis variable set including an aftertreatment system value, and a fueling basis variable set including at least one of an aftertreatment system value and an air handling system value; an aftertreatment target determiner structured to determine an aftertreatment reference value set in response to the aftertreatment basis variable set; an air handling target determiner structured to determine an air handling reference value set in response to the air handling basis variable set; and a fueling target determiner structured to determine a fueling reference value set in response to a fueling basis variable set. The controller optionally includes a system control circuit comprising at least one of a fuel control circuit, an air handling control circuit, and an aftertreatment control circuit and structured to provide one or more control commands in response to the first reference value set, the second reference value set, and the third reference value set. 
     Additional aspects of the disclosure relate to a method comprising interpreting a first basis variable set for a fuel system having a first response time; determining a first reference value set for a fuel control commander in response to the first basis variable set within a first time period determined in response to the first response time; interpreting a second basis variable set for an air handling system having a second response time being slower than the first response time; determining a second reference value set for an air handling control commander in response to the second basis variable set within a second time period determined in response to the second response time; interpreting a third basis variable set for an aftertreatment system having a third response time being slower than the second response time; determining a third reference value set for an aftertreatment control commander in response to the third basis variable set within a third time period determined in response to the third response time; and providing one or more control commands to each of the fuel system, the air handling system, and the aftertreatment system in response to the first reference value set, the second reference value set, and the third reference value set, respectively. 
     Yet further aspects of the disclosure relate to a method comprising interpreting a third basis variable set for an aftertreatment system; determining a third reference value set for an aftertreatment control commander in response to a third basis variable set; interpreting a second basis variable set for an air handling system, the second basis variable set including an aftertreatment system value; determining a second reference value set for an air handling control commander in response to the second basis variable set; interpreting a first basis variable set for a fuel system, the first basis variable set including at least one of an aftertreatment system value and an air handling system value; and determining a first reference value set for a fuel control commander in response to the first basis variable set. 
     While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic illustration of an engine system including a fuel subsystem, an air handling subsystem, and an aftertreatment subsystem, according to some embodiments of the disclosure. 
         FIG. 2  is a schematic illustration of a processing subsystem including a controller to perform certain operations to control the fuel subsystem, the air handling subsystem, and the aftertreatment subsystem of  FIG. 1 , according to some embodiments of the disclosure. 
         FIG. 3  is a schematic illustration of an engine system showing the flow of parameters between subsystems having different response times, according to some embodiments of the disclosure. 
     
    
    
     While the invention is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the invention to the particular embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION 
       FIG. 1  is a schematic illustration of an engine system  100  utilizing reference values to control system performance at various time constants, according to some embodiments of the disclosure. The system  100  cooperatively controls system components, such as subsystems, to provide engine performance within a specification or a requirement set of the system  100 . As shown, the system  100  includes an engine  105  and various subsystems, such as a fuel system  110 , an air handling system  115 , and an aftertreatment system  120  (which are also considered subsystems to the overall system  100 ). An example system  100  includes a controller  125  (e.g., ECM) in operative communication with the engine  105 , which provides and receives signals related to various engine components, such as receiving measurement signals from sensors disposed in the engine  105  and providing control signals or commands to the subsystems. The example controller  125  is in operative communication with other components of the system  100 , such as the subsystems  110 ,  115 ,  120 , in a similar manner. As used herein throughout, operative communication means an operative coupling by wire, wirelessly, mechanically, electronically, optically, magnetically, by network, et cetera, or any suitable combinations thereof. 
     Real-time or online controllers for internal combustion engines, particularly in vehicle applications are notoriously resource limited in processing performance and capability due to size limitations, cost pressures for mass production, requirements to robustly function in harsh environments due to the use of inexpensive and non-state-of-the-art computing equipment. Previously known engine control systems in the art rely on the generation of tables calibrated to provide operating commands in response to a variety of operating conditions. Robust control based on calibration tables alone involves numerous tables and results in certain disadvantages. Generating numerous tables require a long calibration period on the limited hardware. The numerous tables must be stored in limited memory. Due to processing time and memory constraints, not all operating conditions can be calibrated, so when conditions arise during operation that are not calibrated, the engine system must run at some nominal or un-calibrated states. 
     Various embodiments of the system  100  according to this disclosure are capable of robust control while reducing the amount of tables to be calibrated and memory required by operating in response to the fundamental principles of physics within the subsystems. Overall processing requirements are also reduced by reserving faster processing capabilities for subsystems that require faster processing in response to the time dynamics and related response times (or speeds) of each subsystem. 
     Some embodiments of the system  100  decouple the generation of reference values (e.g., target values) from the generation of command values. The example system  100  generates one or more reference values in response to one or more basis variables. The reference values provide target values for each subsystem&#39;s performance. Though many variables can affect subsystem performance, key basis variables are selected to characterize a majority of effects in the subsystem based on fundamental physical principles. By calibrating the system  100  in response to the one or more key basis variables, the system can be calibrated for a reduced set of operating conditions, which reduces the number of tables generated and stored during calibration, thereby reducing the processing time or power required during calibration and memory storage requirements. For example, the example system  100  is calibrated for one or more of a steady state condition, a cold start condition, and a regeneration condition without another set of tables for various altitudes. 
     One or more commands are generated in response to the target values. In some embodiments, the commands are the reference values. In other embodiments, the command values are adjusted in response to physical or emissions constraints (or objectives) of the particular subsystem. Non-limiting examples of commands include a start-of-injection (SOI) (including main, pilot, and post), a rail pressure, a fuel injection, a mass charge flow (MCF), an exhaust gas recirculation (EGR) fraction, a pumping work target, a target selective catalytic reduction (SCR) conversion efficiency, a target system out NO X , a target ammonia slip, and a trajectory (over time) of any of the foregoing parameters. 
     Various embodiments decouple the generation of target values (and associate command values) for each subsystem. Such a configuration utilizes an organized a flow of parameters among the subsystems having different time constants (related to dynamics and response times) so that the processing subsystem can treat parameters from slower subsystems as static. For example, each of the example subsystems  110 ,  115 ,  120  has a different response time. The response times may be so different that each subsystem responds on a different order of magnitude than other subsystems in the system  100 . The fuel subsystem  110  has a response time on the order of milliseconds. The example air handling subsystem  115  has a response time on the order of seconds. The example aftertreatment subsystem  120  has a response time on the order of minutes. The example system  100  overall also has a cumulative emissions requirement measured on the order of several minutes or hours. Response speed is proportional to response time in the sense that a faster response speed corresponds to a faster response time (e.g., responds in less time). The example controller  125  is calibrated for operation to perform operations to robustly control the example system  100  utilizing these varying response times to reduce processing requirements, especially for the slower subsystems. 
     Calibration of each subsystem is independent of the calibration of the other subsystems. Advantages are realized during calibration, such that when an improved value for a subsystem is identified in the middle of engine calibration, that value can be used to update the calibration for that subsystem. In this manner, the calibration for the entire system need not be restarted, which avoids rework while improving robustness. In some embodiments, the system is calibrated by sequentially calibrating the subsystems. An example calibration begins with a set of basis variables for a fuel system target determiner, which optionally includes a state of the air handling subsystem and/or a state of the aftertreatment subsystem treated as static, and the fuel system target determiner is calibrated for providing target values to the fuel subsystem controller. The calibration continues with a set of basis variables for the air handling system target determiner, which optionally includes a state of the aftertreatment subsystem treated as static, and the air handling target determiner is calibrated for providing target values to the air handling subsystem controller. Then, the calibration moves on with a set of basis variables for the aftertreatment system target determiner, and the aftertreatment target determiner is calibrated for providing target values to the aftertreatment subsystem controller. As a particular target determiner is calibrated, the discovery of an improved variable or relationship between variables, which affects subsystem performance, can be incorporated into a recalibration for the particular target determiner only. For example, if the air handling subsystem for a calibrated air handling target determiner changes an air handling component (e.g., turbocharger), the calibrations of the fueling target determiner and the aftertreatment target determiner need not be recalibrated. Because calibration for a particular subsystem is not dependent on the calibration of another subsystem, only the air handling target determiner could be recalibrated. Therefore, advantages in calibration time and/or effort are facilitated, especially when parts of the subsystems change or otherwise need to be recalibrated for different targets. 
     Turning now to the components of the system  100 , the fuel system  110  is in operative communication with the engine  105  and provides fuel for combustion. The fuel system  110  delivers a fueling amount at one or more specific times to one or more cylinders during each combustion cycle. In some embodiments, the fuel is fed through an injector directly into an engine cylinder, for example, when the engine  105  uses diesel fuel. In other embodiments, the fuel is mixed with air charge before entering an engine cylinder, for example, when the engine  105  uses gasoline or natural gas fuel. The physical components of the fuel system  110  may be controlled by physical fuel controller  112 . The fuel controller  112  provides control signals to the physical components of the fuel system  110 , such as a fuel pressure pump and fuel injectors, in response to one or more fueling command values. 
     The air handling system  115  provides air to the engine  105  for combustion with fuel. An example air handling system  115  includes an air handling controller  117  in operative communication with one or more components of the air handling system to provide control signals to the physical air handling system components in response to one or more command values. As illustrated, the air handling system  115  includes an optional turbocharging system including at least one turbocharger, each including a compressor  130  and a turbine  135 . The turbocharging system receives exhaust and provides compressed air. In some embodiments, the compressor  130  is driven by the turbine  135  in a turbocharging configuration, wherein the compressor  130  is the air intake side of a turbocharger and the turbine  135  is the exhaust side of the turbocharger. In various embodiments, the turbocharging system of the air handling system  115  includes a waste gate  137  for bypassing the turbine  135  to control the speed of the turbine  135  and compressor  130 , for example, to avoid excessive speed. In other embodiments, the turbocharging system includes a variable geometry turbocharger (VGT), which facilitates controlling the speed of the turbine  135  and compressor  130 . 
     The example system includes a wastegate turbocharger. However, the airhandling system  115  may include any type of air handling system, including without limitation a naturally aspirated system, a fixed geometry turbocharger, a variable geometry turbocharger, a compressor bypass turbocharger, a dual turbocharger (series or parallel), and combinations thereof. 
     The system  100  includes a system air intake  140  into which air enters from the ambient environment. The air flows into and out of the compressor  130  to engine air intake  145 . The engine  105  may include an intake manifold operatively coupled to the engine air intake  145  to deliver the air to the intake ports of the cylinders. The system may include an intercooler, charger air cooler (not shown), and/or bypass systems therefore. After combustion, exhaust flows from the engine  105  to engine exhaust  150 . The engine  105  may include an exhaust manifold operatively coupled to the exhaust ports of the cylinders to collect the exhaust and direct the exhaust to the engine exhaust  150 . 
     Some of the exhaust is directed into an exhaust gas recirculation (EGR) system that is also part of the air handling system  115 . The EGR system directs a portion of the exhaust to EGR pathway  165  to engine air intake  145 . The EGR system may include an EGR valve  167  to control the flow (e.g., EGR fraction) of exhaust gases back to the engine air intake  145 . The example EGR system is a high pressure EGR system having the EGR pathway  165  being coupled upstream of the turbine  135  and downstream of the compressor  130 . Some embodiments, alternatively or in addition, include a low pressure EGR system having the EGR pathway  165  being coupled downstream of the turbine  135  and upstream of the compressor  130 . The exhaust flows into and out of the turbine  135  to aftertreatment inlet  155 . 
     The example EGR system may additionally or alternatively include an EGR cooler (not shown) structured to cool the exhaust in the EGR pathway  165 . The EGR valve  167  may be positioned upstream (hotside) or downstream (coolside) of the EGR cooler. Where present, the EGR cooler may additionally be provided with a bypass valve. 
     The aftertreatment system  120  receives the exhaust from aftertreatment inlet  155  and at least a portion of the exhaust is expelled at the aftertreatment outlet  160 , which may also be referred to as the system outlet or tailpipe. The aftertreatment system  120  includes devices to treat emissions before exiting the tailpipe, such as one or more of a particulate filter or diesel particulate filter (DPF)  121 , a selective catalytic reduction (SCR) system  122  to chemically reduce components of the exhaust, a NO X  reductant fluid system  123  (e.g., a diesel exhaust fluid system) to provide NO X  reductant fluid to the exhaust, and an oxidation catalyst  126  to chemically oxidize components of the exhaust. The aftertreatment controller  124  is in operative communication with one or more of the aftertreatment components  121 ,  122 ,  123 ,  126  to provide control signals to physical components of the aftertreatment system in response to one or more command values. The EGR system may also be considered part of the aftertreatment system  120 . 
     The controller  125  performs certain operations to control one or more subsystems of an internal combustion engine, such as one or more of a fuel system  110 , an air handling system  115 , and an aftertreatment system  120 . In certain embodiments, the controller  125  forms a portion of a processing subsystem including one or more computing devices having memory, processing, and communication hardware. The controller  125  may be a single device or a distributed device, and the functions of the controller may be performed by hardware and/or as computer instructions on a non-transient computer readable storage medium. 
     The logical relationship among the controllers and their functionality may be implemented in any known manner. Physical controllers  112 ,  117 , and  124  are shown as separate from controller  125  in  FIG. 1 . However, any number of these controllers may alternatively be implemented as part of controller  125 . For example, the controllers may be implemented in a single physical device, or in another example, as a distributed device. 
     In certain embodiments, the controller  125  includes one or more definers, determiners, commanders, and control circuits that functionally execute the operations of the controller. The description herein including definers, determiners, commanders, and/or control circuits emphasizes the structural independence of certain aspects of the controller  125 , and illustrates one grouping of operations and responsibilities of the controller. Other groupings that execute similar overall operations are understood within the scope of the present application. Definers, determiners, commanders, and/or control circuits may be implemented in hardware and/or as computer instructions on a non-transient computer readable storage medium and may be distributed across various hardware or computer based components. 
     Example and non-limiting implementation elements include sensors providing any value determined herein, sensors providing any value that is a precursor to a value determined herein, datalink and/or network hardware including communication chips, oscillating crystals, communication links, cables, twisted pair wiring, coaxial wiring, shielded wiring, transmitters, receivers, and/or transceivers, logic circuits, hard-wired logic circuits, reconfigurable logic circuits in a particular non-transient state configured according to a specification, any actuator including at least an electrical, hydraulic, or pneumatic actuator, a solenoid, an op-amp, analog control elements (springs, filters, integrators, adders, dividers, gain elements), and/or digital control elements. 
       FIG. 2  is a schematic illustration of an example processing subsystem  200  including a controller  125  to perform certain operations to control the fuel subsystem  110 , the air handling subsystem  115 , and/or the aftertreatment subsystem  120  shown in  FIG. 1 , according to some embodiments. 
     The controller  125  typically includes one or more parameters or data structures, such as but not limited to values, variables, commands, trajectories, targets, and sets thereof. These parameters or data structures may be provided to, provided by, and used by any of the definers, determiners, and commanders in the controller  125 . Further, some parameters or data structures  202  are received by the controller  125  from a component external to the controller  125  or other source, which may be provided to and used by any of the operational structures in the controller  125  (e.g., definers, determiners, or commanders). Some parameters or data structures may also be provided by the controller  125  to a component external to the controller  125  or other destination, such as control command(s)  250 . Data structures may be provided to the controller  125  as sensor measurements, which may be physical measurements or virtual measurements. Virtual sensor measurements are determined or interpreted from sensor measurements and/or other data structures in the controller  125 . In some cases, virtual sensor measurements are the output of a definer, determiner, or commander of the controller  125 . 
     Certain operations described herein include operations to interpret and/or to determine one or more parameters or data structures. 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. 
     The example controller  125  includes a system parameter definer  204 . An example system parameter definer  204  interprets one or more parameters in the controller in response to received parameters  202  and/or other parameters in the controller  125 . The interpreted parameters are provided to the controller  125  and are available for use by other operational structures (e.g., definers, determiners, commanders, or circuits). 
     In various embodiments, to perform the functions herein throughout discussed, the system parameter definer  204  may include, but is not limited to, a rotations per minute (RPM) sensor, an accelerator, an oxygen sensor, a temperature sensor, a pressure sensor (e.g., absolute or differential), a flow sensor, a humidity sensor, a NO X  sensor, an ammonia sensor, an analog to digital (ADC) converter, a processor, a non-transient computer readable storage medium, computer readable instruction(s) stored on a non-transient computer readable storage medium, a bus, and/or wired/wireless connection hardware. In other embodiments, one or more of these may also be excluded from the system parameter definer  204 . 
     In some embodiments, the fueling basis variable set  206  is interpreted by the system parameter definer  204 . An example fueling basis variable set  206  characterizes closed cycle efficiency (CCE), which is a measure of the efficiency of combustion within the cylinder. The fueling target determiner  208  determines a fueling reference value set  210  in response to the fueling basis variable set  206 . An example fueling reference value set  210  corresponds to target values for the fuel system  110  during operation. In various embodiments, some target values are conformed to a specification set of one or more physical controllers of the fuel system  110  (e.g., during calibration). 
     In various embodiments, to perform the functions herein throughout discussed, the fueling target determiner  208  may include, but is not limited to, a processor, a non-transient computer readable storage medium, computer readable instruction(s) stored on a non-transient computer readable storage medium, a bus, and/or a wired/wireless connection hardware. In other embodiments, one or more of these may also be excluded from the fueling target determiner  208 . 
     An air handling basis variable set  212  may be interpreted by the system parameter definer  204 . An example air handling basis variable set  212  characterizes open cycle efficiency (OCE), which is a measure of the efficiency of the engine system for bringing air into a cylinder before intake valve closing. The air handling target determiner  214  determines an air handling reference value set  216  in response to the air handling basis variable set  212 . An example air handling reference value set  216  corresponds to target values for the air handling system  115  during operation. In various embodiments, some target values are conformed to a specification set of one or more physical controllers of the air handling system  115  (e.g., during calibration). 
     In various embodiments, to perform the functions herein throughout discussed, the air handling target determiner  214  may include, but is not limited to, a processor, a non-transient computer readable storage medium, computer readable instruction(s) stored on a non-transient computer readable storage medium, a bus, and/or wired/wireless connection hardware. In other embodiments, one or more of these may be excluded from the air handling target determiner  214 . 
     In some embodiments, the aftertreatment basis variable set  218  is interpreted by the system parameter definer  204 . The aftertreatment target determiner  220  determines an aftertreatment reference value set  222  in response to the aftertreatment basis variable set  218 . An example aftertreatment reference value set  222  corresponds to target values for the aftertreatment system  120  during operation. In various embodiments, one or more target values are conformed to a specification set of one or more physical controllers of the aftertreatment system  120  (e.g., during calibration). 
     In various embodiments, to perform the functions herein throughout discussed, the aftertreatment target determiner  220  may include, but is not limited to, a processor, a non-transient computer readable storage medium, computer readable instruction(s) stored on a non-transient computer readable storage medium, a bus, and/or wired/wireless connection hardware. In other embodiments, one or more of these may be excluded from the aftertreatment target determiner  220 . 
     An example aftertreatment basis variable set  218  includes a cumulative emission trajectory  252  to characterize a moving average of one or more emissions in one or more receding time horizons. An example cumulative emission trajectory  252  utilizes a time horizon over a day. Other non-limiting examples of cumulative emission trajectories utilize a time horizon over a week or a month. The cumulative emission trajectory  252  is optionally compared to a cumulative emission target, which is determined in response to any of a number of reasons. For example, a cumulative emission target may be set: to achieve long-term compliance with regulatory requirements; to trade-off emissions credits or actual emissions with another engine or another program (e.g. a set of engine types or company); and/or to meet a fleetwide emissions target. A person of ordinary skill in the art having the benefit of the disclosure herein would be enabled to set an appropriate cumulative emission target for any of these or similar reasons. An example aftertreatment reference value set  222  is determined to bend the cumulative emissions trajectory  252  toward the cumulative emission target, which is selected to increase or decrease cumulative emissions over a time period. 
     Further embodiments of the system parameter definer  204  interpret fueling system value(s)  224 , air handling system value(s)  226 , and/or aftertreatment system value(s)  228 . The system value(s)  224 ,  226 ,  228  may be dynamic in character at a rate related to the response rate of the respective subsystem. Example rates for interpreting system value(s)  224 ,  226 ,  228  are faster than the response rate of the respective subsystem. The example system parameter definer  204  provides the system value(s)  224 ,  226 ,  228  to any one or more of the target determiners  208 ,  214 ,  220 . Example reference value sets  210 ,  216 , and  222  are further determined in response to the system value(s)  224 ,  226 ,  228 . 
     Example fueling system values  224  include, without limitation, any temperature, flowrate, predicted efficiency (in any unit), and/or pressure for any fueling system component, such as a fuel rail pressure, a start-of-injection value, or a fueling amount value. Non-limiting examples of fueling system components include the fuel tank, the fuel rail, the fuel pump, and the fuel itself. 
     Example air handling system values  226  include, without limitation, the composition of air and/or charge gas, temperature (anywhere in the air handling system), volumetric or mass flowrate (anywhere in the air handling system), predicted efficiency (in any unit), and/or the pressure for any air handling system component, such as an in-cylinder [O 2 ] value (oxygen concentration), a mass charge flow value, an exhaust manifold pressure (EMP) value, an exhaust manifold temperature (EMT) value, an intake manifold pressure (IMT) value, an intake manifold pressure (IMP) value, a trapped charge mass value, and an air-to-fuel ratio (AFR) value. Non-limiting examples of predicted efficiency include turbine efficiency, compressor efficiency, and the volumetric efficiency of the engine. Non-limiting examples of air handling system components include the turbocharger (any type), exhaust gas recirculation (EGR) system (including cooler, valve, bypass, main line, etc), cylinder valves, upstream intake valve, downstream exhaust valve, intercooler, manifolds, engine brake hardware, air filter, temperature sensors, pressure sensors, and delta pressure sensors. 
     Example aftertreatment system values  228  include, without limitation, the temperature (anywhere in the aftertreatment system), the flow rate through any aftertreatment component, the predicted efficiency of any aftertreatment component, the pressure drop of any aftertreatment component, the soot loading of any component, the ash loading of any component, the ammonia (NH 3 ) storage of any component, the NO X  storage of any component, the regeneration need of any component, the time or distance to regeneration of any component, the excess conversion capacity of any component, the outlet composition of any component, the reductant fluid rate, the reductant fluid capability, a temperature requirement of any component, and a flow rate requirement of any component. Non-limiting examples of predicted efficiency include NO to NO 2  conversion rate, soot conversion by NO 2 , soot conversion by O 2 , NO X  conversion into N 2  directly, NH 3  conversion on a cleanup catalyst, hydrocarbon oxidation conversion rate, and NO X  conversion on a selective catalytic reduction (SCR) catalyst. Non-limiting examples of aftertreatment system components include oxidation catalyst, close-coupled catalyst, a reductant fluid injector, a decomposition residence volume, a NO X  adsorber catalyst (NAC), a filter and/or catalyzed filter, a three-way and/or four-way catalyst, an SCR catalyst, an ammonia oxidation catalyst (AMOX), and bypasses of these. 
     The example controller  125  includes a subsystem manager  240  to coordinate and/or control the subsystems to meet a target system performance in response to operational information  242 . System performance is managed by setting targets for the target determiners or the subsystem controllers associated with each subsystem. The subsystem manager recognizes that certain subsystems require cooperation from other subsystems in order to meet their targets. For example, the aftertreatment system may not be able to meet a particular NO X  target or heat flux requirement without adjustments made upstream, in the fuel subsystem or the air handling subsystem. In this manner, the subsystem manager  240  facilitates management of compositions of matter that move through the engine system to achieve one or more overall system targets. Non-limiting examples of compositions to be managed include constituent values—such as the presence or absence of oxygen, inert materials, fuel amount, fuel composition, particulates, an emission (any type), a reductant, and/or an unburned hydrocarbon—and/or state values—such as a temperature, a pressure, a humidity, a heat capacity, an efficiency value (any type), a loading capacity, a flow capacity, and/or a space velocity. 
     In various embodiments, to perform the functions herein throughout discussed, the subsystem manager  240  may include, but is not limited to, a subsystem control circuit, a processor, a non-transient computer readable storage medium, computer readable instruction(s) stored on a non-transient computer readable storage medium, a bus, and/or wired/wireless connection hardware. In other embodiments, one or more of these may be excluded from the subsystem manager  240 . 
     The example controller  125  can be described as having multiple control levels, with one level being superior to and capable of overriding an inferior control level. For example, subsystem manager  240  can be considered a level of control superior to a level of control including the one or more target determiners. The level of control including the one or more target determiners can be considered a level of control superior to a level of control including the subsystem controllers. The superior level of control provides targets to the inferior level of control for overall system control. However, the inferior level of control (e.g., aftertreatment target determiner) may also provide targets to the superior level of control (e.g., subsystem manager), which may be used to affect other operational structures (e.g., fuel target determiner) in the inferior level of control. 
     Target system performance may relate to any of cumulative emissions, equivalent brake specific fuel consumption (EBSFC), brake specific fuel consumption (BSFC), energy availability or total energy at the input of the aftertreatment system, and/or the ratio of natural gas fuel to diesel fuel. Brake power information is obtained optionally from a virtual torque sensor or an actual torque sensor. Some targets relate to optimal system performance and/or improved system performance in relation to a nominal system performance. Nominal system performance as used herein includes, but is not limited to, performance of the system without the operations of the subsystem manager, operations of the system under normal conditions, and/or operations of the system without any adjustments from nominal target values. Examples of optimal and/or incrementally improved system performance include minimizing or improving a cost function of any type (e.g., fuel consumption, an emissions output, or component utilization) or maximizing or improving performance of any type (e.g. torque output, service life of any component, or passive regeneration of particulates). 
     Optimal or incrementally improved system performance depends on the mode of the engine (e.g., nominal operation or thermal management), the type of aftertreatment (e.g., including NO X  aftertreatment or no SCR aftertreatment), and/or the type of fuel (e.g., diesel, natural gas, or dual fuel). Non-limiting examples of optimal system performance targets include minimizing an equivalent brake-specific fuel consumption (EBSFC) for fuel and diesel exhaust fluid (DEF) in an engine system having an SCR; minimizing a brake-specific fuel consumption (BSFC) in an engine system without an SCR; and maximizing a substitution ratio (e.g., natural gas/diesel fuel quantity) in an engine system utilizing dual-fuel capabilities (e.g. natural gas and diesel fuel). Further non-limiting examples of optimal target system performance targets relate to improving and/or optimizing reductant fluid consumption, catalyst life usage for any selected aftertreatment component, and EGR valve cycling per unit time (e.g., to maximize EGR valve life). 
     Example operational information  242  is a set of parameters that relate to variables of interest (e.g. engine states and aftertreatment states) and constraints (e.g., mechanical constraints including peak cylinder pressure (PCP) and turbo speed) within the system. Operational information  242  is selected to manage the system and meet a specific target system performance. Example specific targets include, but are not limited to, NO X  at various points in the system, PM production and regeneration in the system, hydrocarbon production in the system, CO or CO 2  production in the system, and fuel and/or other fluid consumption in the system. Operational information  242  optionally includes or is interpreted in response to fueling system value(s)  224 , air handling system value(s)  226 , and/or aftertreatment system value(s)  228 . In addition, operational information  242  includes or is interpreted in response to one or more variable sets  206 ,  212 ,  218 . 
     As illustrated, the example operational information  242  is organized to meet NO X , PM, and/or consumption specific targets within the system  100 . The organized subsets include NO X  operational information  244 , particulate matter (PM) operational information  246 , and/or consumption operational information  248  (any type or combination, including reductant consumption). Additionally or alternatively, operational information  242  relates to the temperature of component, the number of cycles used by a valve, run-time utilization, or the temperature gradient across a catalyst substrate. 
     Non-limiting examples of NO X  operational information  244  include a nominal EONO X  value  260 , a nominal DENO X  value  262 , a nominal SONO X  value  264 , an NO amount, an NO 2  amount, an NO and/or NO 2  to NO X  ratio, a NO X  conversion efficiency, an ammonia storage capacity, a heat demand by the aftertreatment system, a torque demand, a torque feedback value (e.g. from a virtual or actual sensor), a subsystem state, an EBSFC 266, BSFC 268, an unburned hydrocarbon amount, a composition of the PM, and/or combinations of these. A nominal value may include a regulatory value, a value under normal operations, and a value that would occur if other adjustments currently being operated were not in operation. 
     Non-limiting examples of PM operational information  246  include a soot loading value, a soot composition value (e.g., particulates versus organic fraction), and an ash production value. Non-limiting examples of consumption operational information  248  include an EBSFC value  266 , a diesel fuel consumption rate, and/or a reductant fluid consumption rate. 
     In some embodiments, the example subsystem manager  240  provides set-point target(s)  241  to one or more of the target determiners  208 ,  214 ,  220 . Each of the target determiners  208 ,  214 ,  220  then adjusts operation to meet the set-point target. Adjusting operation includes determining or modifying one or more reference value sets in response to the set-point target(s)  241 . 
     Non-limiting types of set-point target(s)  241  include optimal set-points, improved set-points, calibrated set-points, and initial reference set-points. Any set-points or types of set-points known in the art or any set-point generation method known in the art may be used. Non-limiting examples of set-point targets include a CCE, a post fueling amount, an oxygen concentration, a charge-to-fuel ratio (CFR), a differential pressure target (ΔP), and an SCR conversion efficiency. A person having skill in the art having the benefit of the disclosure herein and information about the particular system  100  would be able to select particular set-points to manage subsystems to meet overall system targets in response to operational information  242  to achieve improvement and/or optimization to meet a target system performance with the subsystem manager  240 . 
     Alternative to, or in addition to, providing set-point target(s)  241 , the example subsystem manager  240  optionally receives a set-point target from one or more of the subsystems. In response, the example subsystem manager  240  optionally provides one or more set-point targets  241  to other subsystems. In one example, the aftertreatment provides a SONO X  set-point target to the aftertreatment subsystem and/or the subsystem manager  240 . In response, the example subsystem manager  240  provides a set-point target to the fuel subsystem and/or the air handling subsystem, which for example, facilitate achieving the SONO X  set-point target or take advantage of excess capacity in the system (e.g., excess SCR capacity) while achieving the SONO X  set-point target. 
     In the illustrated embodiment, the example subsystem manager  240  is in operative communication with one or more target determiners  208 ,  214 ,  220  to send and receive the operational information  242 , constraints, and/or set-point target(s)  241 . In such arrangement, the subsystem manager  240  is positioned to coordinate (e.g., optimize to a target, minimum, or maximum) the subsystems to achieve an overall target system performance. 
     Particular types of set-point targets  241  are provided to target determiners selected to achieve the target. The example subsystem manager  240  provides set-point target(s)  241 , such as an engine-out NOx (EONO X ) target  254  to the fueling target determiner  208 , a NO X  conversion (DENO X ) target  256  to the air handling target determiner  214 , and/or a system out NO X  (SONO X ) target  258  to the aftertreatment target determiner  220  in response to NOx operational information  244  to minimize EBSFC while meeting regulatory NO X  values. For example, the EONO X  target value  254  is increased above a nominal EONO X  value  260  when the operational information indicates the SCR has excess conversion capacity at a particular SCR temperature without needing more reductant fluid. 
     In some embodiments, nominal values are provided by the respective target determiner, and the target determiner receives a modified target value as the set-point target  241  from the subsystem manager  240 . In an example embodiment, the fueling target determiner  208  determines a nominal EONO X  value  260 . The example fueling target determiner  208  provides the nominal EONO X  value  260  to the subsystem manager  240 . The nominal EONO X  value  260  is optionally modified. The subsystem manager  240  determines an EONO X  target  254  in response to the nominal EONO X  value  260  and operational information  242 , such as NOX operational information  244 . The EONO X  target  254  is provided to the fueling target determiner  208  as a set-point target  241 . The fueling target determiner  208  determines the fueling reference value set  210  in response to one or more of the EONO X  target  254  as the set-point target  241  and the fueling basis variable set  206 . 
     In a similar manner, the air handling target determiner  214  optionally determines a nominal DENO X  value  262  for DENO X  target  256 . The aftertreatment target determiner  220  also optionally determines a nominal SONO X  value  264  for SONO X  target  258 . 
     In various embodiments, the subsystem manager  240  optionally determines one or more reference value sets  210 ,  216 ,  222 . The one or more reference value sets  210 ,  216 ,  222  are determined by the example subsystem manager  240  in response to operational information  242 . 
     In some embodiments, reference value sets  210 ,  216 ,  222  are optionally determined by modifying initial reference value sets provided by the respective target determiner  208 ,  214 ,  220 . In such embodiments, the modified reference value sets  210 ,  216 ,  222  are provided back to the respective target determiners from the subsystem manager  240 . 
     Optionally, the target determiners are overridden by the subsystem manager  240 . For example, an override optionally occurs when the subsystem manager  240  determines a particular reference value for a subsystem (e.g., post fueling amount) in response to another subsystem requesting a particular target value (e.g., aftertreatment heat flux). In such cases, reference value sets  210 ,  216 ,  222  are optionally provided directly to the system control commander  230  (e.g., system control circuit) or are passed through a target determiner  208 ,  214 ,  220  to the system control commander. 
     Some embodiments of the subsystem manager  240  iteratively determine or modify the set-points or reference value sets  210 ,  216 ,  222  at the end of a cycle of iteration(s), which may be determined in response to achieving a target value, reaching a predetermined time limit, or meeting some other condition (e.g., a subsystem requesting or requiring a control command). 
     The example subsystem manager  240  models the operational information  242  at least one time step ahead, for example, to predict or estimate some of the operational information  242 . Non-limiting examples of at least one time step ahead include one time-step ahead, two time-steps ahead, three-time steps ahead, four-time steps ahead, or five-time steps ahead. Non-limiting examples of a time step include a processor execution step, a modeling iteration step, and a discrete time interval. Example reference value sets  210 ,  216 ,  222  are further determined and/or modified in response to the modeled operational information. 
     The one or more reference value sets  210 ,  216 ,  222  are provided to the system control commander  230  for determining control command(s)  250  in response to the reference value set(s). An example system control commander  230  includes a fuel control commander  232 , an air handling control commander  234 , and/or an aftertreatment control commander  236 . Each example control commander  232 ,  234 ,  236  provides one or more command(s)  250  to the respective subsystem. The control command(s)  250  include (e.g., pass through) or are interpreted in response to the one or more reference values from the reference value sets  210 ,  216 ,  222 . In various embodiments, one or more of the control commanders  230 ,  232 ,  234 ,  236  comprise a respective control circuit (e.g., a system control circuit, a fuel control circuit, an air handling control circuit, and/or an aftertreatment control circuit). 
     Each control commander  232 ,  234 ,  236  is optionally calibrated to a particular subsystem, for example, to adjust for manufacturing variances. The calibrated system control commander  230  selectively provides the control command(s)  250  in response to the calibration(s). To the extent that the control command(s)  250  include the one or more reference value sets  210 ,  216 ,  222 , the reference value sets are optionally modified in response to the calibration. 
     In various embodiments, to perform the functions herein throughout discussed, the fuel control commander  232  may include, but is not limited to, a fuel injector, a fuel rail pressure pump, a processor, a non-transient computer readable storage medium, computer readable instruction(s) stored on a non-transient computer readable storage medium, a bus, and/or wired/wireless connection hardware. In other embodiments, one or more of these may also be excluded from the fuel control commander  232 . 
     In additional or alternative embodiments, the fuel control commander  232  comprises a fuel control circuit. To perform the functions described herein throughout, an example fuel control circuit may include, but is not limited to, an analog circuit, a digital circuit, an analog-to-digital converter (ADC) or vice versa, a processor, a non-transient computer readable storage medium, computer-readable instruction(s) stored on a non-transient computer readable storage medium, a bus, and/or wired/wireless connection hardware. In other embodiments, one or more of these may also be excluded from the fuel control circuit. 
     In various embodiments, to perform the functions herein throughout discussed, the air handling control commander  234  may include, but is not limited to, an EGR valve, a VGT, an engine fan, a fuel injector, a fuel rail pressure pump, a processor, a non-transient computer readable storage medium, computer readable instruction(s) stored on a non-transient computer readable storage medium, a bus, and/or wired/wireless connection hardware. In other embodiments, one or more of these may be excluded from the air handling control commander  234 . 
     In additional or alternative embodiments, the air handling control commander  234  comprises an air handling control circuit. To perform the functions described herein throughout, an example air handling control circuit may include, but is not limited to, an analog circuit, a digital circuit, an analog-to-digital converter (ADC) or vice versa, a processor, a non-transient computer readable storage medium, computer-readable instruction(s) stored on a non-transient computer readable storage medium, a bus, and/or wired/wireless connection hardware. In other embodiments, one or more of these may also be excluded from the air handling control circuit. 
     In various embodiments, to perform the functions herein throughout discussed, the aftertreatment control commander  236  may include, but is not limited to, a diesel exhaust fluid (DEF) valve, an ammonia fluid valve, a fuel injector, an EGR valve, a VGT, a processor, a non-transient computer readable storage medium, computer readable instruction(s) stored on a non-transient computer readable storage medium, a bus, and/or wired/wireless connection hardware. In other embodiments, one or more of these may be excluded from the aftertreatment control commander  236 . 
     In additional or alternative embodiments, the aftertreatment control commander  236  comprises an aftertreatment control circuit. To perform the functions described herein throughout, an example aftertreatment control circuit may include, but is not limited to, an analog circuit, a digital circuit, an analog-to-digital converter (ADC) or vice versa, a processor, a non-transient computer readable storage medium, computer-readable instruction(s) stored on a non-transient computer readable storage medium, a bus, and/or wired/wireless connection hardware. In other embodiments, one or more of these may also be excluded from the aftertreatment control circuit. 
     The control command(s)  250  are received by the example controllers  112 ,  117 ,  124  of each subsystem  110 ,  115 ,  120 . In response, the fuel system  110 , the air handling system  115 , and/or the aftertreatment system  120  operates in response to the control command(s)  250 . 
     The subsystems  110 ,  115 ,  120  have different response times or rates, for example, on different orders of magnitude. Thus, the example target determiners  208 ,  214 ,  220  and example control commanders  232 ,  234 ,  236  update at intervals in response to the respective subsystem such that the determiners, commanders, and/or circuits update at a similar rate as the corresponding subsystem. For example, when the fuel subsystem  110  has a response time on the order of milliseconds, the fueling target determiner  208  and fuel control commander  232  also update on a similar interval. 
     However, an example air handling subsystem  115  has a response time on the order of seconds, which is at least an order of magnitude slower than the fuel subsystem  110 . The example air handling target determiner  214  and the example air handling control commander  234  then update on a similar interval to the air handling subsystem  115 , which is at least an order of magnitude slower than the fuel-related structures, such as fueling target determiner  208  and fuel control commander  232 . 
     Even though the example controller  125  overall updates on the order of milliseconds to provide robust control for the fuel subsystem  110 , the processing for the example air handling subsystem  115  is updated at a much lower rate while still providing robust control. Establishing a lower rate of updating for the air handling-related structures, such as air handling target determiner  214  and air handling control commander  234 , reduces overall processing requirements by providing updates at a rate appropriate to a particular subsystem. Furthermore, when the example aftertreatment subsystem  120  has a response time on the order of minutes, the same reduction in overall processing requirements may be achieved by establishing an even lower rate of updating for the aftertreatment-related structures, such as aftertreatment target determiner  220  and aftertreatment control commander  236 . 
     The division of processing by time constant facilitates flexible hardware configurations. For example, processing may be distributed across processing units with varying speeds and/or across processing cores within the same processing unit. Slower and less expensive processing units may be used for a slower rate of control for slower subsystems, and faster more expensive processing unit may be used for a faster rate of control for faster subsystems. Furthermore, distributed processing in a multi-processor or multi-engine control commander (ECM) architecture facilitates modularity of the engine system, particularly for the processing subsystem. One having ordinary skill in the art, having the benefit of the disclosure herein, would recognize that the benefits of the present disclosure may be achieved even with a single processor executing instructions at varying time constants, for example not executing aftertreatment operations every execution cycle, to provide robust control with reduced processing requirements. 
     Additionally, the processing requirements of an example system are further reduced by establishing a flow of parameters between the operational structures corresponding to each subsystem, perhaps as best shown in  FIG. 3 . One of skill in the art, having the benefit of the disclosures herein, will recognize that the processing subsystem  200  and the controller  125  perform operations that improve various technologies and provide improvements in various technological fields. Without limitation, example and non-limiting technology improvements include improvements in combustion performance of internal combustion engines, improvements in emissions performance, aftertreatment system regeneration, engine torque generation and torque control, engine fuel economy performance, improved durability of exhaust system components for internal combustion engines, and engine noise and vibration control. Without limitation, example and non-limiting technological fields that are improved include the technological fields of internal combustion engines, fuel systems therefore, aftertreatment systems therefore, air handling devices therefore, and intake and exhaust devices therefore. 
       FIG. 3  is another schematic illustration of example system  100  showing the flow of parameters between subsystems having different response times, according to some embodiments. Generally, a slower response time corresponds to a lower response speed, whereas a faster response time corresponds to a greater response speed. The subsystems  110 ,  115 ,  120  are illustrated from left to right in the order of increasingly slower response time. The fuel system  110  has the fastest response time. The example air handling system  115  has a slower response time than the fuel system, for example, at least an order of magnitude slower. The aftertreatment system  120  has a slower response time than air handling system  115 , for example, at least an order of magnitude slower. 
     As shown, the example processing subsystem  200  includes fuel controller  112  as part of fuel system  110 , air handling controller  117  as part of air handling system  115 , and aftertreatment controller  124  as part of aftertreatment system  120 . The response times of each controller  112 ,  117 ,  124  are similar to the response times of the respective subsystem, or are at least on the same order of magnitude. 
     Example processing subsystem  200  also includes fueling target determiner  208 , air handling target determiner  214 , and aftertreatment target determiner  220 . The target determiners  208 ,  214 ,  220  are in operative communication with the controllers  112 ,  117 ,  124 . A system control commander as shown in  FIG. 2  is not shown here but may be included and in operative communication with the target determiners and the controllers. A system parameter definer as shown in  FIG. 2  is also not shown here but may be included and in operative communication with the subsystems (e.g., to a sensor or a controller) and the target determiners. 
     The target determiners  208 ,  214 ,  220  determine and provide reference value sets  210 ,  216 ,  222 . Each target determiner has a response time similar to or at least on the same order of magnitude as the corresponding subsystem. The controllers  112 ,  117 ,  124  operate their respective subsystems in response to the respective reference value sets  210 ,  216 ,  222 . 
     The reference value sets  210 ,  216 ,  222  are determined in response to basis variable sets  206 ,  212 ,  218 . As can be seen, the fueling basis variable set  206  includes at least one air handling system value  226  and/or at least one aftertreatment system value  228 . Although the system values  226 ,  228  may be dynamic, because the air handling system  115  has a slower response time than the fuel system  110 , the air handling system value(s)  226  may be treated as static for one or more time steps by the fueling target determiner  208  for determining the fueling reference value set  210 . In a similar manner, because the aftertreatment system  120  has a slower response time than the air handling system  115 , the aftertreatment system value(s)  228  may be treated as static for one or more times steps by the air handling target determiner  214  for determining the air handling reference value set  216 . 
     When operational, the system  100  produces emissions over time, for example, at the tailpipe of aftertreatment system  120 . The cumulative emissions may be measured on the order of several minutes or hours and be estimated as a cumulative emission trajectory  252 . Although the cumulative emission trajectory  252  may be dynamic, the aftertreatment target determiner  220  may treat the cumulative emission trajectory  252  as static for one or more time steps for determining the aftertreatment reference value set  222 . 
     In operation, an aftertreatment reference value set  222  is determined in response to an aftertreatment basis variable set  218 , which may include a cumulative emission trajectory  252 , at a time period determined in response to the response time of the aftertreatment system  120  and/or aftertreatment controller  124 . The aftertreatment reference value set  222  includes targets for controlling the aftertreatment system  120 . The conditions in the aftertreatment system  120  may be available as aftertreatment system value(s)  228  in the processing subsystem  200 . 
     The air handling reference value set  216  is determined in response to an air handling basis variable set  212 , which may include the aftertreatment system value(s)  228 , at a time period determined in response to the response time of the air handling system  115  and/or air handling controller  117 . The conditions in the air handling system  115  may be available as air handling system value(s)  226  in the processing subsystem  200 . 
     The fueling reference value set  210  is determined in response to a fueling basis variable set  206 , which may include the aftertreatment system value(s)  228  and/or the air handling system value(s)  226 , at a time period determined in response to the response time of the fuel system  110  and/or fuel controller  112 . 
     An example time period for the air handling reference value set  212  is greater than the time period for the fueling reference value set  210 . An example time period for the aftertreatment reference value set  222  is greater than the time period for the air handling reference value set  216 . Although the time periods for determining each reference value set are different in duration, the time periods may overlap. The determination of each reference value set is not necessarily tied to waiting for another reference value set to be determined. 
     The ordered flow of parameters from slower response time subsystems to control structures corresponding to faster response time subsystems and the significant difference (e.g., an order of magnitude) in response times between subsystems allows for a cascaded parameters and hierarchical time-divided control scheme for robustly operating system  100 . Overall reductions in processing, memory, and calibration time requirements are achieved. 
     The example processing subsystem  200  further includes subsystem manager  240 . As illustrated, the example subsystem manager  240  provides one or more set-point target(s)  310 ,  312 ,  314  to the target determiners  208 ,  214 ,  220  to coordinate the subsystems  110 ,  115 ,  120  to achieve a target system performance. An example set-point target  310  provided to the fueling target determiner  208  is a target EONO X  value  254 . An example set-point target  312  provided to the air handling target determiner  214  is a target DeNO X  value  256 . An example set-point target  314  provided to the aftertreatment target determiner  314  is a target SONO X  value  258 . The target determiners  208 ,  214 ,  220  optionally determine and provide reference value sets  210 ,  216 ,  222  in response to the set-point targets  310 ,  312 ,  314 . In some embodiments, the set-point targets  310 ,  312 ,  213  are provided in response to the subsystem manager  240  receiving the reference value sets  210 ,  216 ,  222 . 
     It is to be understood that the above description is intended to be illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reading and understanding the above description. For example, it is contemplated that features described in association with one embodiment are optionally employed in addition or as an alternative to features described in associate with another embodiment. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.