WO2015095127A1

WO2015095127A1 - Exhaust throttle for controlling the condition of an exhaust gas stream

Info

Publication number: WO2015095127A1
Application number: PCT/US2014/070496
Authority: WO
Inventors: Brian R. Alderfer; Robert E. Cochran; Daniel J. Mohr; Raymond C. Shute
Original assignee: Cummins Inc.
Priority date: 2013-12-20
Filing date: 2014-12-16
Publication date: 2015-06-25

Abstract

The present disclosure relates to a controller apparatus for controlling the condition of an exhaust gas stream. The controller apparatus includes an exhaust detection module that is structured to detect a condition of an exhaust gas stream from an internal combustion engine and generate an exhaust gas report. The controller apparatus also includes an exhaust demand module that is structured to receive the exhaust gas report and an exhaust gas request and generate an exhaust gas demand. Still further, the controller apparatus includes an exhaust throttle module that is structured to receive the exhaust gas demand and send actuation commands to an exhaust throttle in the exhaust gas stream. The disclosure also includes a related system and method.

Description

EXHAUST THROTTLE FOR CONTROLLING THE CONDITION OF AN

EXHAUST GAS STREAM

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

[0001] The present application claims the benefit of priority from U.S. Provisional Patent Application Serial No. 61/919,397, filed on December 20, 2013, the disclosure of which is hereby incorporated by reference in its entirety for all purposes.

FIELD

[0002] This disclosure relates to engine control systems, and more particularly relates to controlling the condition of an exhaust gas stream by actuating an exhaust throttle.

BACKGROUND

[0003] 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 acceptable emission standards, to which all engines must comply. Emission tests for internal combustion engines typically monitor the release of various pollutants, including carbon monoxide, nitrogen oxides (NOx), and unburned hydrocarbons (UHC). Aftertreatment components, such as catalysts and filters, have been implemented in exhaust gas aftertreatment systems to eliminate many of the regulated pollutants present in exhaust gas generated from engines. Additionally, exhaust gas recirculation systems have also been implemented to improve engine efficiency and improve the quality of the exhaust gas that is ultimately released into the atmosphere.

[0004] However, the efficiency and general functionality of these improvements

(aftertreatment systems and exhaust gas recirculation systems) are dependent on the condition of the exhaust gas stream. For example, if the pressure of the exhaust gas stream is too low, exhaust gas will not flow through the exhaust gas recirculation system. Additionally, if the temperature of the exhaust gas is too low, the various aftertreatment components may become clogged and/or may become ineffective due to particulate accumulation. Various solutions have been developed to overcome these difficulties. For example, variable geometry turbochargers have been implemented to manipulate the pressure of the exhaust gas stream and thereby control the pressure drop across the exhaust gas recirculation system. In other situations, heat exchangers or other complex components have been added to engine systems to manipulate the temperature of the exhaust gas stream to maintain and/or regenerate the aftertreatment components. While these conventional solutions may be effective, they are often complex and expensive.

SUMMARY OF THE INVENTION

[0005] The subject matter of the present application has been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art of engine control systems that have not yet been fully solved by currently available engine systems. Accordingly, in certain embodiments, a controller apparatus, a system, and a method are disclosed for controlling the condition of an exhaust gas stream in an inexpensive (comparatively) manner. In other words, the controller apparatus, system, and method described in the present disclosure overcome many of the shortcomings of the prior art.

[0006] The present disclosure relates to a controller apparatus for controlling the condition of an exhaust gas stream. The controller apparatus includes an exhaust detection module that is configured to detect a condition of an exhaust gas stream from an internal combustion engine and generate an exhaust gas report. The controller apparatus also includes an exhaust demand module that is configured to receive the exhaust gas report and an exhaust gas request and generate an exhaust gas demand. Still further, the controller apparatus includes an exhaust throttle module that is configured to receive the exhaust gas demand and send actuation commands to an exhaust throttle in the exhaust gas stream. [0007] In one embodiment, the exhaust demand module includes a ranking hierarchy of exhaust gas requests. The exhaust gas demand module compares at least a highest ranked exhaust gas request with the exhaust gas report to generate the exhaust gas demand. The exhaust gas report may include one or more of the following: pressure, temperature, composition, and flow rate of the exhaust gas stream. Further, the conditions detected by the detection module may also include or more of the following: conditions of an intake stream, conditions of an internal combustion engine, and conditions of an aftertreatment sub-system. In one embodiment, the exhaust gas request is input from a user. In another embodiment, the exhaust gas request is input from another module or system (e.g., the main electronics control module). The exhaust throttle may be positioned downstream of a turbine in a turbocharger.

[0008] The present disclosure also relates to an engine system for controlling the condition of an exhaust gas stream. The engine system includes an internal combustion engine that has an intake manifold and an exhaust manifold. An intake stream flows through the intake manifold and an exhaust gas stream flows through the exhaust manifold. The system further includes an exhaust gas recirculation assembly fluidly connected downstream of the intake manifold. The exhaust gas recirculation assembly divides the exhaust gas stream into a recycle stream and a vent stream. Still further, the system includes a turbocharger that has a turbine in fluid communication with the vent stream and a compressor in fluid communication with the intake stream. The system includes an exhaust throttle fluidly connected downstream of the turbine.

[0009] In one embodiment, the turbocharger is a fixed-geometry turbocharger. In another embodiment, the turbocharger has a waste-gate. The system may further include an exhaust gas aftertreatment sub-system fluidly connected downstream of the exhaust throttle. The exhaust gas aftertreatment sub-system may include a diesel oxidation catalyst. In another embodiment, the exhaust gas aftertreatment sub-system includes a particulate filter. In yet another embodiment, the exhaust gas aftertreatment sub-system includes a selective catalytic reduction component.

[0010] The present disclosure also relates to a method for controlling the condition of an exhaust gas stream. The method includes detecting a condition of an exhaust gas stream and comparing the condition of the exhaust gas stream to an exhaust gas request to generate an exhaust gas demand. The method also includes actuating an exhaust throttle to realize the exhaust gas demand. In one embodiment, comparing the condition of the exhaust gas stream to the exhaust gas request includes consulting a ranking hierarchy of exhaust gas requests. Accordingly, the exhaust gas demand may include an adjustment to the condition of the exhaust gas stream based on the difference between the condition of the exhaust gas stream and a highest ranking exhaust gas request. The method may further include actuating an intake throttle to realize the exhaust gas demand and detecting a condition of an aftertreatment sub-system.

[0011] Reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present disclosure should be or are in any single embodiment of the invention. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed herein. Thus, discussion of the features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same embodiment.

[0012] Furthermore, the described features, advantages, and characteristics of the disclosure may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the subject matter of the present application may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the disclosure. Further, in some instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the subject matter of the present disclosure. These features and advantages of the present disclosure will become more fully apparent from the following description and appended claims, or may be learned by the practice of the disclosure as set forth hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] A more particular description of the disclosure briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the disclosure and are not therefore to be considered to be limiting of its scope, the subject matter of the present application will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which:

[0014] Figure 1 is a schematic block diagram of a controller apparatus for controlling the condition of an exhaust gas stream, according to certain embodiments;

[0015] Figure 2 is a schematic block diagram of a system for controlling the condition of an exhaust gas stream, according to certain embodiments;

[0016] Figure 3 is a schematic block diagram of the system from Figure 2 but also showing an exhaust gas recirculation cooler and an intake throttle, according to certain embodiments;

[0017] Figure 4 is a schematic block diagram of the system of Figure 3 with the intake throttle removed but adding an aftertreatment sub-system, according to certain embodiments;

[0018] Figure 5 is a schematic block diagram of the system of Figure 4 with the exhaust gas recirculation assembly removed, according to certain embodiments;

[0019] Figure 6 is a schematic block diagram of the system of Figure 5 but also showing additional components of the aftertreatment sub-system, according to certain embodiments; and

[0020] Figure 7 is a schematic flow chart diagram of a method for controlling the condition of an exhaust gas stream, according to certain embodiments.

DETAILED DESCRIPTION

[0021] Reference throughout this specification to "one embodiment," "an embodiment," "certain embodiments," or similar language indicates that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Appearances of the phrases "in one embodiment," "in an embodiment," "certain embodiments," and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment. Similarly, the use of the term "implementation" indicates an implementation having a particular feature, structure, or characteristic described in connection with one or more embodiments of the present disclosure, however, absent an express correlation to indicate otherwise, an implementation may be associated with one ormore embodiments.

[0022] Figure 1 is a schematic block diagram of an example controller apparatus 100 for controlling the condition of an exhaust gas stream 12. The controller apparatus 100 includes an exhaust detection module 110, an exhaust demand module 120, and an exhaust throttle module 130. Generally, the present disclosure relates to implementing an exhaust throttle in an engine system to regulate the conditions (e.g., pressure, temperature) of an exhaust gas stream.

[0023] Certain embodiments described in the present disclosure include a controller and/or a controller apparatus. In certain embodiments, the controller forms a portion of a processing subsystem including one or more computing devices having memory, processing, and communication hardware. The controller 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.

[0024] In certain embodiments, the controller includes one or more modules structured to functionally execute the operations of the controller. The description herein including modules emphasizes the structural independence of the aspects of the controller, 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. Modules may be implemented in hardware and/or as computer instructions on a non-transient computer readable storage medium, and modules may be distributed across various hardware or computer based components. More specific descriptions of certain embodiments of controller operations are included in the section referencing Fig. 1.

[0025] Example and non-limiting module 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 the module 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.

[0026] Certain operations described herein include operations to receive and/or to determine one or more parameters. Receiving 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.

[0027] The exhaust detection module 110 is structured to detect, sense, and/or receive one or more conditions of an exhaust gas stream. An example exhaust detection module 110 communicates with one or more physical sensors, such as pressure sensors, temperature sensors, flow-rate sensors, etc., to detect the conditions of the exhaust gas stream.

Additionally or alternatively, the exhaust detection module 110 may receive one or more expected or calculated exhaust gas conditions from another engine system, such as the main electronic control module of an engine or vehicle. The example detection module 110 communicates and/or receives information relating to the condition of the exhaust gas stream. Exhaust gas condition information, termed 'exhaust gas report' throughout the present disclosure, is passed to the exhaust demand module 120. In certain embodiments, the detection module 110 may further detect, sense, and/or receive other data/information, including without limitation one or more conditions of the intake stream, of the engine., and/or of a turbocharger present in the system.

[0028] In certain embodiments, the exhaust demand module 120 further receives an exhaust gas request. Example exhaust gas request 120 information includes, without limitation, input from a user, input from a separate controller apparatus, and/or input from the main electronics control module. As described in greater detail following, an example exhaust demand module 120 accesses a ranking system and/or a ranking hierarchy relating to available exhaust gas requests. An example exhaust demand module 120, after comparing the exhaust gas report and the exhaust gas request, generates an exhaust gas demand, and provides the exhaust gas demand to the exhaust throttle module 130. The exhaust gas demand, in one embodiment, is an adjustment to the existing/detected condition of the exhaust gas stream. Example and non- limiting exhaust gas demands include an exhaust gas temperature target, an exhaust gas temperature threshold value (as a maximum or minimum), an exhaust gas flow rate target, an exhaust gas flow rate threshold value (as a maximum or minimum), an exhaust gas pressure target value, and/or an exhaust gas pressure threshold value (as a maximum or minimum). An example exhaust throttle module 130 receives the demand and communicates with an exhaust throttle, and/or other physical actuators or controllers, in response to the demanded

adjustment. Communications in response to the demanded adjustment include

communications to achieve the exhaust gas demand, to progress acceptably toward the exhaust gas demand, and/or to selectively delay progressing toward the exhaust demand for a period depending upon other system conditions (e.g. a fault, power demand, actuator saturation, and/or other system limitation).

[0029] Figure 2 is a schematic block diagram of an example system 200 for controlling the condition of an exhaust gas stream 12. Figure 2 also shows a controller apparatus 100, consistent with an embodiment of a controller apparatus 100 from Figure 1, and depicts the various modules 110, 120, 130 interacting with the example system 200. The system includes an internal combustion engine 210. The engine includes an engine block and a cylinder head mounted to the engine block. The engine block defines a plurality of combustion cylinders, and various cavities and channels used to store and transport fluids within the engine 210. The engine block may be formed of a one-piece monolithic construction using any of various techniques, such as casting. The block may be made from a metal, such as aluminum, iron, or similar metal. Although not depicted, the engine 210 may include a flywheel housing interface to which a flywheel housing can be mounted and various other components and connections to which external plumbing (e.g., conduits, hoses, and pipes) can be mounted.

[0030] An example system 200 includes any internal combustion engine known in the art. Another example system 200 includes an internal combustion engine having one or more reciprocating pistons. Yet another example system 200 includes any internal combustion engine having an exhaust gas recirculation (EGR) system, a turbocharger, and/or one or more aftertreatment components requiring an elevated temperature from time to time (e.g. to support a regeneration, a constituent storage value where storage is temperature

dependent, and/or to promote one or more chemical reactions). An example system including a turbocharger includes a turbocharger that is not a variable geometry turbocharger (VGT), which may further include a waste-gated turbocharger.

[0031] The internal combustion engine 210 can be a compression-ignited internal combustion engine, such as a diesel fueled engine, or a spark-ignited internal combustion engine, such as a gasoline fueled engine operated lean. Within the internal combustion engine 210, air from the atmosphere is combined with fuel to power the engine.

Combustion of the fuel and air produces and exhaust gas stream 12 that is operatively vented to an exhaust manifold 212. The exhaust gas stream 12 may then be divided into two separate streams 21, 22 by an exhaust gas recirculation assembly 220. The two streams are a vent stream 21 and a recycle stream 22. The exhaust gas recirculation assembly 220 may include a piping manifold and/or various valves to divide the exhaust gas stream 12 into a recirculating portion (recycle stream 22) and a portion that ultimately vents to the atmosphere (vent stream 21). For example, the exhaust gas recirculation assembly 220 can include an EGR valve that is actuatable to direct (e.g., vent) a portion of the received exhaust gas into the atmosphere as expelled exhaust (vent stream 21) and direct a portion of the received exhaust gas into an exhaust gas recirculation (EGR) line (recycle stream 22) for recirculation back into the combustion chambers of the engine 210.

[0032] Because the exhaust gas recirculation assembly 220 is upstream of the turbine 231, the exhaust gas stream 12 flowing through the exhaust gas recirculation assembly 220 has a higher pressure than exhaust gas flowing out of the turbine 231 due to the pressure losses associated with the expansion and work transferred to the turbine 231 by the exhaust gas stream 12. The system 200 also includes a turbocharger 230 that includes a turbine 231 operatively coupled to the vent stream 21 of the exhaust gas stream 12. Exhaust gas flowing through the turbine 231 rotates the turbine, which drives a compressor 232 of the turbocharger 230 and thereby compresses the intake stream 11. In one

embodiment, the turbocharger 230 may be a fixed-geometry turbocharger. In another embodiment, the turbocharger 230 may have a waste-gate.

[0033] The system also includes an exhaust throttle 240 that can be manipulated by the controller apparatus 100 to control the condition of the exhaust gas stream 12. The exhaust throttle 240 may be any mechanism that can control the flow rate and/or pressure of a fluid stream. Generally, the exhaust throttle 240 includes a housing and a control surface that interacts with the exhaust gas stream 12 (specifically the vent stream 21) to increase backpressure or decrease backpressure.

[0034] For example, as previously described above, if the detection module 110 senses that the pressure (i.e., 'condition' 109) of the exhaust gas stream 12 is lower than the pressure of the intake stream 11, such information may be passed to the exhaust demand module 120 in the form of an exhaust gas report 111. The exhaust demand module 120 then analyzes the exhaust gas report 111 in view of the received exhaust gas requests 119. The exhaust demand module 120 may determine that, despite considering engine constraints/restrictions and/or other requests, the backpressure of the exhaust gas stream 12 (upstream of the throttle valve 240) should be increased (e.g., to create a desirable pressure drop across the recirculation assembly 220, thus allowing a portion of exhaust gas to flow from the exhaust side of the system 200 to the intake side of the system 200. The exhaust demand module 120 would then generate an exhaust gas demand 121 that is sent to the exhaust throttle module 130. The exhaust throttle module 130 may then communicate with the exhaust throttle 240, via actuation commands 131, to create the demanded backpressure.

[0035] Although not depicted in Figure 2, or in the other schematic block diagrams of the present disclosure, it is contemplated that additional components may be implemented in the system 200. For example, several mixers may be included to mix different fluids together. In one embodiment, a fuel/air mixer is included where liquid fuel and atmospheric air may be combined to create the intake stream 11. In another embodiment, another mixer may be implemented for combining the recycle stream 22 with the intake stream 11. The mixer(s) may be a portion of tubing/piping. In another embodiment, the mixer(s) may include a chamber where the fluid streams are combined. In yet another embodiment, the mixer(s) may include mixing elements, such as baffles or actuators, which promote the mixing of the fluid streams. Additionally, the system 200 may include various additional components that may be implemented with the present disclosure. For example, a fuel pre-heater, heat exchangers, valves, and air/fuel injectors, among others, may also be included in the system 200.

[0036] Further, although not depicted, the compressed intake stream 12 flowing out of the compressor 232 of the turbocharger 230 may flow into a charge air cooler, which decreases the temperature of the intake air charge for creating a denser intake charge. The system 200 may also include various valves, gauges, controllers, and actuators and how each of these elements may be configured to controllably operate the system 200. In addition, various additional components, such as air filters, sensors, pumps, etc., may also be implemented in certain embodiments of the system. It is contemplated that these additional components and elements (not depicted) fall within the scope of the present disclosure.

[0037] Figure 3 is a schematic block diagram of the system 200 from Figure 2 but also showing an exhaust gas recirculation cooler 224 and an intake throttle 15, according to one embodiment. As described preceding, various other fluid processing components may be implemented with the disclosed system 200. For example, Figure 3 shows an exhaust gas recirculation cooler 224 in the exhaust gas recirculation assembly 220. This cooler 224 may be used to make the recycle stream 22 denser so as to increase the efficiency of the combustion reaction. The intake throttle 15 may be used in conjunction with the exhaust throttle 240 to further control the pressure difference between the exhaust gas stream 12 and the intake stream 11 , thus enhancing the level of control of the exhaust gas recirculation assembly 220. Additionally or alternatively, an intake throttle 15 operated in conjuction with an exhaust throttle 240 provides for additional temperature management capability.

[0038] Figure 4 is a schematic block diagram of the system 200 of Figure 3 with the intake throttle 15 removed but adding an aftertreatment sub-system 250, according to one embodiment. Generally, the exhaust gas aftertreatment sub-system 250 is configured to reduce the number of pollutants contained in the exhaust gas generated by the engine 210 before venting the exhaust gas into the atmosphere. In the depicted embodiment, the exhaust gas aftertreatment system 250 includes a diesel oxidation catalyst (DOC) 251 and a particulate matter filter 252. As discussed below with reference to Figure 5, the aftertreatment system 250 can include additional components, such as additional DOCs and filters as well as selective catalytic reduction systems and/or ammonia oxidation catalysts.

[0039] The exhaust gas aftertreatment sub-system 250 can also include, for example, a three-way catalyst, other filters, adsorbers, and the like, for treating (i.e., removing pollutants from) the exhaust gas stream 12. The catalysts in the aftertreatment sub-system 250 may include substrates that have a catalytic layer disposed on a washcoat or carrier layer. The carrier layer can include any of various materials (e.g., oxides) capable of suspending the catalytic layer therein. The catalyst layer is made from one or more catalytic materials selected to react with (e.g., oxidize) one or more pollutants in the exhaust gas. The catalytic materials of the three-way catalyst can include any of various materials, such as precious metals platinum, palladium, and rhodium, as well as other materials, such as transition metals cerium, iron, manganese, and nickel. Further, the catalyst materials can have any of various ratios relative to each other for oxidizing and reducing relative amounts and types of pollutants as desired. Although depicted as distinct components, in one embodiment various components (catalyst and filter) may be integrated in a single element.

[0040] The exhaust throttle 240 can be manipulated by the controller apparatus 100 to affect the temperature condition of the exhaust gas stream 12. As described above, the exhaust throttle 240 may be any mechanism that can control the flow rate and/or pressure of a fluid stream. Generally, the exhaust throttle 240 includes a housing and a control surface that interacts with the exhaust gas stream 12 (specifically the vent stream 21) to increase backpressure or decrease backpressure.

[0041] In the engine system 200, if the detection module 110 senses that one or more of the aftertreatment components 251, 252 requires regeneration or that the temperature of exhaust gas stream 12 is too low (i.e., 'condition' 109), such information may be passed to the exhaust demand module 120 in the form of an exhaust gas report 111. The exhaust demand module

120 can then analyze the exhaust gas report 111 in view of the received exhaust gas requests 119. The exhaust demand module 120 may determine that, despite considering engine constraints/restrictions and/or other requests, the exhaust throttle 240 should be actuated to increase the backpressure of the exhaust gas stream 12 (upstream of the throttle valve 240), thus causing the temperature of the exhaust gas stream 12 to rise. This temperature rise is due, in part, to the decreased efficiency of the engine. When the pressure in the exhaust manifold 212 is comparatively higher, the engine 210 needs to work harder to expel the exhaust gases from the cylinders of the engine 210. This causes the exhaust temperature to increase, which in turn affects the efficiency/regeneration of the various aftertreatment components. The exhaust demand module 120 would then generate an exhaust gas demand

121 that is sent to the exhaust throttle module 130. The exhaust throttle module 130 may then communicate with the exhaust throttle 240, via actuation commands 131, to create the demanded backpressure and corresponding temperature increase.

[0042] Figure 5 is a schematic block diagram of the system 200 of Figure 4 with the exhaust gas recirculation assembly 120 removed, according to one embodiment. As described above, the exhaust throttle 240 can be used to increase the pressure of the exhaust gas stream 12 for a variety of purposes. One purpose can be to increase the desirable pressure drop across the recirculation assembly 220 to drive exhaust gases through the recirculation line and into the intake stream 11. However, another purpose for increasing the pressure of the exhaust gas stream 12 is to increase the temperature of the exhaust gas stream 12 to benefit the aftertreatment components. In one embodiment, as depicted in Figure 5, the exhaust throttle 240 can be implemented in the absence of an exhaust gas recirculation assembly 220. In such a situation, the exhaust throttle can be exclusively actuated to facilitate the efficient operation/regeneration of the aftertreatment sub-system 250.

[0043] Figure 6 is a schematic block diagram of the system 200 of Figure 5 but also showing an additional component 153 of the aftertreatment sub-system 150, according to one embodiment. As described above, the exhaust gas aftertreatment sub- system 250 may include a selective catalytic reduction (SCR) system. Similar to DOC's and filters, SCR systems are highly temperature dependent and controlling the condition of the exhaust gas stream 12 can increase the efficiency of such aftertreatment components.

[0044] The schematic flow diagram and related description which follows provides an illustrative embodiment of performing procedures for controlling the condition of an exhaust gas stream. Operations illustrated are understood to be exemplary only, and operations may be combined or divided, and added or removed, as well as re -ordered in whole or part, unless stated explicitly to the contrary herein. Certain operations illustrated may be implemented by a computer executing a computer program product on a non-transient computer readable storage medium, where the computer program product comprises instructions causing the computer to execute one or more of the operations, or to issue commands to other devices to execute one or more of the operations.

[0045] Figure 7 is a schematic flow chart diagram of a procedure 700 for controlling the condition of an exhaust gas stream 12, according to one embodiment. The procedure 700 includes an operation 702 to detect a condition 109 of an exhaust gas stream 12. The procedure 700 also includes an operation 704 to compare the condition 109 of the exhaust gas stream 12 to an exhaust gas request 119 to generate an exhaust gas demand 121 The procedure 700 further includes an operation 706 to actuate an exhaust throttle 240 to realize the exhaust gas demand 121.

[0046] The described features, structures, advantages, and/or characteristics of the subject matter of the present disclosure may be combined in any suitable manner in one or more embodiments and/or implementations. In the above description, numerous specific details are provided to impart a thorough understanding of embodiments of the subject matter of the present disclosure. One skilled in the relevant art will recognize that the subject matter of the present disclosure may be practiced without one or more of the specific features, details, components, materials, and/or methods of a particular embodiment or implementation. In other instances, additional features and advantages may be recognized in certain embodiments and/or implementations that may not be present in all embodiments or implementations.

Further, in some instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the subject matter of the present disclosure. The features and advantages of the subject matter of the present disclosure will become more fully apparent from the above description and appended claims, or may be learned by the practice of the subject matter as set forth above.

[0047] In the above description, certain terms may be used such as "up," "down," "upper," "lower," "horizontal," "vertical," "left," "right," and the like. These terms are used, where applicable, to provide some clarity of description when dealing with relative relationships. But, these terms are not intended to imply absolute relationships, positions, and/or

orientations. For example, with respect to an object, an "upper" surface can become a "lower" surface simply by turning the object over. Nevertheless, it is still the same object. Further, the terms "including," "comprising," "having," and variations thereof mean "including but not limited to" unless expressly specified otherwise. An enumerated listing of items does not imply that any or all of the items are mutually exclusive and/or mutually inclusive, unless expressly specified otherwise. The terms "a," "an," and "the" also refer to "one or more" unless expressly specified otherwise.

[0048] Additionally, instances in this specification where one element is "coupled" to another element can include direct and indirect coupling. Direct coupling can be defined as one element coupled to and in some contact with another element. Indirect coupling can be defined as coupling between two elements not in direct contact with each other, but having one or more additional elements between the coupled elements. Further, as used herein, securing one element to another element can include direct securing and indirect securing. Additionally, as used herein, "adjacent" does not necessarily denote contact. For example, one element can be adjacent another element without being in contact with that element. [0049] 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.

[0050] 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.

[0051] As used herein, the phrase "at least one of, when used with a list of items, means different combinations of one or more of the listed items may be used and only one of the items in the list may be needed. The item may be a particular object, thing, or category. In other words, "at least one of means any combination of items or number of items may be used from the list, but not all of the items in the list may be required. For example, "at least one of item A, item B, and item C" may mean item A; item A and item B; item B; item A, item B, and item C; or item B and item C. In some cases, "at least one of item A, item B, and item C" may mean, for example, without limitation, two of item A, one of item B, and ten of item C; four of item B and seven of item C; or some other suitable combination.

[0052] The present subject matter may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

WHAT IS CLAIMED IS:

1. An apparatus comprising:

an exhaust detection module structured to detect a condition of an exhaust gas stream from an internal combustion engine and generate an exhaust gas report;

an exhaust demand module structured to receive the exhaust gas report and an exhaust gas request and generate an exhaust gas demand; and

an exhaust throttle module structured to receive the exhaust gas demand and send actuation commands to an exhaust throttle in the exhaust gas stream.

2. The controller apparatus of claim 1, wherein the exhaust demand module comprises a ranking hierarchy of exhaust gas requests, wherein the exhaust gas demand module compares at least a highest ranked exhaust gas request with the exhaust gas report to generate the exhaust gas demand.

3. The controller apparatus of claim 1, wherein the exhaust gas report comprises one or more of the following: pressure, temperature, composition, and flow rate of the exhaust gas stream.

4. The controller apparatus of claim 1, wherein the conditions detected by the detection module further comprise one or more of the following: conditions of an intake stream, conditions of an internal combustion engine, and conditions of an aftertreatment subsystem.

5. The controller apparatus of claim 1, wherein the exhaust gas request comprises input from a user.

6. The controller apparatus of claim 1, wherein the exhaust gas request comprises input from another module or sub-system.

7. The controller apparatus of claim 1, wherein the exhaust gas request comprises input from a main electronics control module.

8. The apparatus of claim 1, wherein the exhaust throttle is positioned downstream of a turbine in a turbocharger.

9. An engine system for controlling the condition of an exhaust gas stream, the system comprising

an internal combustion engine comprising an intake manifold and an exhaust manifold, wherein an intake stream flows through the intake manifold and an exhaust gas stream flows through the exhaust manifold;

an exhaust gas recirculation assembly fluidly connected downstream of the intake manifold, wherein the exhaust gas recirculation assembly divides the exhaust gas stream into a recycle stream and a vent stream;

a turbocharger comprising a turbine in fluid communication with the vent stream and a compressor in fluid communication with the intake stream; and

an exhaust throttle fluidly connected downstream of the turbine.

10. The engine system of claim 9, wherein the turbocharger comprises a fixed- geometry turbocharger.

11. The engine system of claim 9, wherein the turbocharger comprises a waste-gate turbocharger.

12. The engine system of claim 9, further comprising an exhaust gas aftertreatment sub-system fluidly connected downstream of the exhaust throttle.

13. The engine system of claim 12, wherein the exhaust gas aftertreatment subsystem comprises a diesel oxidation catalyst.

14. The engine system of claim 12, wherein the exhaust gas aftertreatment subsystem comprises a particulate filter.

15. The engine system of claim 12, wherein the exhaust gas aftertreatment subsystem comprises a selective catalytic reduction component.

16. A method for controlling the condition of an exhaust gas stream, the method comprising:

detecting a condition of an exhaust gas stream;

comparing the condition of the exhaust gas stream to an exhaust gas request to generate an exhaust gas demand; and

actuating an exhaust throttle to realize the exhaust gas demand.

17. The method of claim 16, wherein comparing the condition of the exhaust gas stream to the exhaust gas request comprises consulting a ranking hierarchy of exhaust gas requests.

18. The method of claim 17, wherein the exhaust gas demand comprises an adjustment to the condition of the exhaust gas stream based on the difference between the condition of the exhaust gas stream and a highest ranking exhaust gas request.

19. The method of claim 16, further comprising actuating an intake throttle to realize the exhaust gas demand.

20. The method of claim 16, further comprising detecting a condition of an aftertreatment sub-system.