WO2025166090A1

WO2025166090A1 - Waste heat recovery system for hydrogen internal combustion engines

Info

Publication number: WO2025166090A1
Application number: PCT/US2025/013914
Authority: WO
Inventors: Arvind Suresh; Bijesh M. SHAKYA; Michael J. Cunningham; J. Steven Kolhouse; Krishna KAMASAMUDRAM; Ashok Kumar; Paul Edmund GWYTHER
Original assignee: Cummins Inc
Current assignee: Cummins Inc
Priority date: 2024-01-31
Filing date: 2025-01-30
Publication date: 2025-08-07
Anticipated expiration: 2026-07-31

Abstract

A system includes an aftertreatment system, a waste heat recovery system, and a controller. The aftertreatment system is coupled to and receives exhaust gas from a hydrogen internal combustion engine. The waste heat recovery system is coupled to the hydrogen internal combustion engine. The waste heat recovery system includes a heat exchanger. The controller is configured to receive temperature data indicative of a first temperature value of the aftertreatment system; compare the first temperature value to a predetermined temperature threshold; responsive to determining that the first temperature value is at or above the predetermined temperature threshold, cause at least a portion of the exhaust gas to flow to the heat exchanger of the waste heat recovery system; and responsive to determining that the first temperature value is below the predetermined temperature threshold, cause the exhaust gas to flow to the aftertreatment system.

Description

WASTE HEAT RECOVERY SYSTEM FOR HYDROGEN INTERNAL

COMBUSTION ENGINES

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This PCT Application claims the benefit of and priority to U.S. Provisional Application No. 63/627,642 filed January 31, 2024, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The present disclosure relates to a waste heat recovery (WHR) system for a hydrogen fueled internal combustion engine system. The WHR system is configured to remove heat from exhaust gases produced by the hydrogen fueled internal combustion engine and convert at least a portion of the removed heat into usable power.

BACKGROUND

10003] Waste heat recovery systems may recover waste heat energy from an internal combustion engine that would otherwise be lost. The more waste heat energy extracted from an internal combustion engine by a WHR system, the greater the potential efficiency of the engine. In other words, rather than the emitted heat energy being lost, the extracted heat energy may be repurposed to, for example, supplement the power output by the internal combustion engine, thereby increasing the efficiency of the system.

SUMMARY

10004] One embodiment relates to a system including an aftertreatment system, a waste heat recovery system, and a controller. The aftertreatment system is coupled to a hydrogen internal combustion engine. The aftertreatment system receives exhaust gas from the hydrogen internal combustion engine. The waste heat recovery system is coupled to the hydrogen internal combustion engine. The waste heat recovery system includes a heat exchanger. The controller includes at least one processor and at least one memory device storing instructions that, when executed by the at least one processor, cause the controller to perform operations. The operations include receiving temperature data indicative of a first temperature value of the aftertreatment system; comparing the first temperature value to a predetermined temperature threshold; responsive to determining that the first temperature value is at or above the predetermined temperature threshold, causing at least a portion of the exhaust gas to flow to the heat exchanger of the waste heat recovery system; and responsive to determining that the first temperature value is below the predetermined temperature threshold, causing the exhaust gas to flow to the aftertreatment system.

[0005] Another embodiment relates to a method. The method includes receiving temperature data indicative of a first temperature value of an aftertreatment system in exhaust gas receiving communication with an engine; comparing the first temperature value to a predetermined temperature threshold; responsive to the first temperature value being at or above the predetermined temperature threshold, causing at least a portion of the exhaust gas to flow to a heat exchanger to reduce a temperature of the exhaust gas; and responsive to the first temperature value being below the predetermined temperature threshold, causing the exhaust gas to flow to the aftertreatment system.

[0006] Yet another embodiment relates to a non-transitory computer readable media storing instructions that, when executed by one or more processors, cause the one or more processors to perform operations. The operations include receiving temperature data indicative of a first temperature value of an aftertreatment system in exhaust gas receiving communication with a hydrogen internal combustion engine; comparing the first temperature value to a predetermined temperature threshold; responsive to the first temperature value being at or above the predetermined temperature threshold, causing at least a portion of the exhaust gas to flow to a heat exchanger to reduce a temperature of the exhaust gas; and responsive to the first temperature value being below the predetermined temperature threshold, causing the exhaust gas to flow to the aftertreatment system.

[0007] Numerous specific details are provided to impart a thorough understanding of embodiments of the subject matter of the present disclosure. The described features of the subject matter of the present disclosure may be combined in any suitable manner in one or more embodiments and/or implementations. In this regard, one or more features of an aspect of the invention may be combined with one or more features of a different aspect of the invention. Moreover, additional features may be recognized in certain embodiments and/or implementations that may not be present in all embodiments or implementations.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a is a block diagram of a hydrogen fueled internal combustion engine system, according to an example embodiment.

[0009] FIG. 2 is a is a block diagram of a waste heat recovery system of the system of FIG. 1, according to an example embodiment.

[0010] FIG. 3 is a block diagram of a controller of the system of FIG. 1, according to an example embodiment.

[0011 J FIG. 4 is a flow diagram of a method of operating the WHR system of FIG. 2, according to an example embodiment.

[0012] FIG. 5 is a flow diagram of a method of adjusting a temperature threshold, according to an example embodiment.

DETAILED DESCRIPTION

[0013] Following below are more detailed descriptions of various concepts related to, and implementations of, methods, apparatuses, computer-readable media, and systems for a waste heat recovery (WHR) system for a hydrogen fueled internal combustion engine system. The WHR system may remove or enable removing heat from exhaust gases produced by the hydrogen fueled internal combustion engine. Before turning to the Figures, which illustrate certain exemplary embodiments in detail, it should be understood that the present disclosure is not limited to the details or methodology set forth in the description or illustrated in the Figures. It should also be understood that the terminology used herein is for the purpose of description only and should not be regarded as limiting. [0014] As described herein, an engine system may include an engine and an exhaust aftertreatment system in exhaust gas receiving communication with the engine. The exhaust aftertreatment system may include one or more components, such as a particulate filter configured to remove particulate matter from exhaust gas flowing in the exhaust gas conduit system, a dosing module (e.g., a doser) configured to supply a dosing fluid to the exhaust gas flowing in the aftertreatment system, and one or more catalyst devices configured to facilitate conversion of the exhaust gas constituents (e.g., nitrogen oxides, NOx, sulfur oxides, SOx, etc.) to less harmful elements (e.g., water, nitrogen, N2, etc.), such as an oxidation catalyst, a selectively catalytic reduction (SCR) system, a three-way catalyst, and so on.

[0015] One or more components of the exhaust aftertreatment system may operate more “efficiently” when a temperature the component(s) is within a predetermined range of temperatures (e.g., greater than a minimum temperature and less than a maximum temperature). As used herein “efficiency” and similar terms, in addition to the plain meaning of the word may be used to characterize a rate of converting an exhaust gas constituent into another substance, such that higher rates indicate higher efficiencies. For example, a SCR catalyst may convert nitrogen oxides (NOx) into nitrogen (N2) and water (H2O). The “efficiency” of the SCR catalyst may be the rate at which the SCR catalyst converts NOx into N2 and H2O. Thus, the SCR catalyst may be more efficient as the rate increases relative to a previous value, and the SCR catalyst may be less efficient as the rate decreases relative to a previous value.

[0016] In an example embodiment, an aftertreatment system component, such as the SCR catalyst, may operate most efficiently when the temperature of the component is between a maximum value and a minimum value. The maximum value and the minimum value may be predetermined based on a chemistry of the component (e.g., a chemistry of the SCR catalyst) and/or a fuel type of the corresponding engine. In the embodiments described herein, the aftertreatment system may be used with a hydrogen combustion engine. An SCR catalyst designed for use with a hydrogen combustion engine may operate most efficiently when the temperature of the SCR catalyst is between 200 °C and 250 °C, inclusive. In contrast, typical diesel exhaust aftertreatment systems may include SCR catalysts that operate most efficiently when the temperature is greater than 250 °C (e.g., 300 °C, 400 °C, etc.). [0017] In conventional engine systems that include waste heat recovery (WHR) systems or units, a heat exchanger of the WHR system is positioned downstream of the aftertreatment system or downstream of an aftertreatment system component, such as an SCR catalyst. WHR systems are conventionally positioned downstream of the aftertreatment system (or a component thereof) to avoid reducing the temperature of the exhaust gas upstream of the aftertreatment system (or a component thereof) because overcooling of the aftertreatment system components may result in decreased component efficiency.

[0018] Advantageously and as described herein, a control system or controller may control the operation of the engine system to selectively reduce the temperature of exhaust gases flowing through the aftertreatment system to maintain the temperature of an aftertreatment system component, such as the SCR catalyst, within a desired or ideal operating range (e.g., between 200 °C and 250 °C, inclusive). More specifically, as described herein, the engine system may include a WHR system or unit that is positioned upstream of the aftertreatment system. More specifically, the WHR systems described herein include a heat exchanger positioned upstream of the aftertreatment system to aid in reducing the temperature of the exhaust gases flowing to the aftertreatment system. Reducing the temperature of the exhaust gases flowing to the aftertreatment system advantageously facilitates maintaining the temperature of the aftertreatment system component within the desired operating range. More specifically, because the desired operating range of an SCR catalyst designed for use with a hydrogen internal combustion engine is less than the desired operating range of an SCR catalyst designed for use with, e.g., a diesel internal combustion engine, it may be desirable to reduce the temperature of exhaust gases flowing to the aftertreatment system.

[0019] As described herein, in some embodiments, a control system or controller may monitor one or more parameters of the components of the engine system using one or more sensors (e.g., actual sensors and/or virtual sensors) to collect sensor data. For example, the sensor data may include a temperature value of the aftertreatment system, such as a temperature of the exhaust gases at an inlet of the aftertreatment system, a temperature of the exhaust gases at an outlet of the aftertreatment system, a temperature of a component of the aftertreatment system, or other temperature regarding the aftertreatment system. In some embodiments, the temperature value is measured by one or more real sensors. In other embodiments, the temperature value is estimated by one or more virtual sensors, based on operational data of the system, such as an engine run time (e.g., a period of time the engine has been operating), a quantity of fuel burned, ambient conditions (e.g., weather, humidity, temperature, etc.), nearby or surrogate temperatures (e.g., measured temperatures of components proximate the aftertreatment system, or other suitable operational data. In some embodiments, the control system may compare sensor data to one or more thresholds to determine whether to cause at least a portion of the exhaust gases flowing to the aftertreatment system to flow through a heat exchanger of the WHR system, upstream of the aftertreatment system. Advantageously, causing the portion of the exhaust gases to flow through the heat exchanger of the WHR system aids in reducing the temperature of the exhaust gases, upstream of the aftertreatment system. In this way, the heat exchanger of the WHR system may be used to maintain the temperature of the aftertreatment system (or one or more components thereof) within a desired operating range of temperature values. Furthermore, because the desired operating range of an SCR catalyst designed for use with a hydrogen internal combustion engine is less than the desired operating range of an SCR catalyst designed for use with, e.g., a diesel internal combustion engine, it may be desirable to reduce the temperature of the exhaust gases upstream of the aftertreatment system. These and other features and benefits are described more fully herein below.

[0020] Referring now to FIG. 1, a schematic view of a block diagram of a system 100 is shown, according to an example embodiment. The system 100 includes an engine 102 and an aftertreatment system 120 in exhaust gas receiving communication with the engine 102. The system 100 includes a controller 140 (as shown in FIG. 3) and an operator input/output (I/O) device 130, where the controller 140 is communicably coupled to each of the aforementioned components.

[00211 In some embodiments, the system 100 includes a turbo device 122 disposed between the engine 102 and the aftertreatment system 120, such that the turbo device 122 is in exhaust gas receiving communication with the engine 102 and exhaust gas providing communication with the aftertreatment system 120. In these embodiments, the aftertreatment system 120 is in exhaust gas receiving communication with the engine 102 (e.g., via the turbo device 122). [0022] In some embodiments, the system 100 is included in a vehicle. The vehicle may be any type of on-road or off-road vehicle including, but not limited to, wheel-loaders, fork-lift trucks, line-haul trucks, mid-range trucks (e.g., pick-up truck, etc.), sedans, coupes, tanks, airplanes, boats, and any other type of vehicle. In other embodiments, the system 100 may be embodied in a stationary piece of equipment, such as a power generator or genset. All such variations are intended to fall within the scope of the present disclosure.

[0023] In the configuration shown in FIG. 1, the engine 102 is a hydrogen internal combustion engine (ICE). The hydrogen ICE may consume hydrogen fuel to generate power. In some embodiments, the engine 102 may be part of a hybrid engine system having a combination of an internal combustion engine and at least one electric machine coupled to at least one battery (not shown). For example, as shown in FIG. 1, the system 100 may include an electric machine 128 (e.g., a motor, a motor generator, an electric starter, etc.) that is coupled to the engine 102 via a shaft 126 (e.g., an output shaft, a drive shaft, a crankshaft, etc.). In some embodiments, the system 100 may be configured as a mild-hybrid powertrain, a parallel hybrid powertrain, a series hybrid powertrain, or a series-parallel powertrain.

[0024] The engine 102 includes one or more cylinders 104 (e.g., combustion cylinders). The cylinders 104 are disposed within a combustion chamber of the engine 102. The cylinders 104 enable combustion of the hydrogen fuel within the engine 102. Combustion of hydrogen fuel causes the engine 102 to rotate, thereby causing rotation of the shaft 126.

[0025] As described herein, “rotating” the engine 102 refers to actuating one or more components of an engine system 100. For example, when the engine 102 is rotated, a crankshaft (e.g., the shaft 126), a flywheel, one or more camshafts one or more timing belts, and/or other components may be rotated to facilitate operation of the engine 102. Further, when the engine 102 is rotated, a piston and a connecting rod may actuate relative to a combustion chamber. Rotation of the one or more camshafts may cause one or more valves (e.g., an intake valve and/or an exhaust valve) to actuate between an open position and a closed position. Rotation of the engine 102 may be measured in rotations per minute (RPM). More specifically, rotation of the engine 102 may be measured by an RPM of the crankshaft (e.g., the shaft 126). [0026] During normal operation of the engine 102, rotation of the engine 102 is caused by the combustion of fuel within a combustion cylinder (e.g., the cylinders 104). More specifically, combustion of fuel within a combustion cylinder (e.g., the cylinders 104) causes rotation of a crankshaft (e.g., the shaft 126) via actuating a piston and a connecting rod. The rotation of the crankshaft (e.g., the shaft 126) may cause the rotation of one or more camshafts (e.g., via one or more timing belts). As described above, rotation of one or more camshafts may cause one or more valves (e.g., an intake valve and/or an exhaust valve) to actuate between an open position and a closed position to allow air and/or an air and fuel mixture to enter the combustion cylinder (e.g., the cylinders 104) and/or to allow an exhaust gas stream to exit the combustion cylinder (e.g., the cylinders 104).

[0027] In some embodiments, rotation of the engine 102 is caused by an electric machine (e.g., the electric machine 128), such as a motor or motor generator. The electric machine 128 may be coupled to the crankshaft (e.g., the shaft 126) directly or indirectly (e.g., via a clutch, a drive shaft, and/or another component). In some embodiments, the electric machine 128 is an electric motor that is coupled to a power source, such as a battery. For example, the electric machine 128 may consume electrical energy (e.g., from the power source) to cause rotation of the crankshaft (e.g., the shaft 126). In other embodiments, the electric machine 128 may be an electric starter, such that rotation of the engine 102 is caused by the electric starter. For example, the electric starter may “crank” or cause rotation of the crankshaft (e.g., the shaft 126) to facilitate starting the engine 102.

[0028] In some embodiments, rotation of the engine 102 is caused by another device, such as a turbine (e.g., turbine 167, shown in FIG. 2) or other power-generating device. The turbine 167 may be coupled to the crankshaft directly or indirectly (e.g., via a clutch, a drive shaft, a gear train, and/or another component). In some embodiments, the turbine 167 may be part of a WHR system 160. For example, the WHR system 160 may include a working fluid (e.g., a coolant) that is heated in the WHR system 160 and forced through the turbine 167 such that the turbine 167 generates power. In some embodiments, the turbine 167 provides mechanical power to the crankshaft (e.g., the shaft 126). For example, the turbine 167 may provide mechanical power to the crankshaft (e.g., the shaft 126) via one or more intermediate components, such as a gear train, a flywheel, and/or another component (e.g., gear train 168, shown in FIG. 2). In other embodiments, the turbine 167 provides power to an electrical system, such as a motor generator or a battery. For example, the turbine 167 may be coupled to a motor generator such that the turbine 167 rotates the motor generator and causes the motor generator to generate electrical power. The electrical power may be stored by a battery. The battery may be coupled to an electric machine 128 that is configured to rotate the crankshaft (e.g., the shaft 126), as described above.

[0029] In some embodiments, the shaft 126 may be rotated by an outside force, such as the electric machine 128 and/or another component of the engine, such as a turbine a flywheel, or other suitable component. In some embodiments, the outside force may supplement the rotation of the shaft 126. That is, the engine 102 and the outside force may cooperate to rotate the shaft 126 concurrently or partially concurrently. In other embodiments the engine 102 and the outside force may rotate the shaft 126 independently. That is, the engine 102 and the outside force may rotate the shaft sequentially (e.g., one after another). In these embodiments, fuel may or may not be provided to the cylinder 104 when the engine 102 is not rotating the shaft 126.

[0030] As shown in FIG. 1, the engine 102 includes six cylinders 104. However, it should be understood that the engine 102 may include more or fewer cylinders 104 (e.g., at least one) than as shown in FIG. 1. Furthermore, the cylinders 104 may be provided in varying arrangements (e.g., in-line, horizontal, V, or other suitable cylinder arrangement).

[0031] The system 100 includes an intake conduit 110 and an intake manifold 112. The intake conduit 110 is configured to route an intake gas stream, including air (e.g., ambient air, compressed air, etc.), to the intake manifold 112. The intake manifold 112 is configured to route the intake gas stream from an intake conduit 110 into the engine 102. More specifically, the intake manifold 112 is configured to route air from the intake conduit 110 to each of the cylinders 104.

[0032] The system 100 includes an exhaust manifold 116 and an exhaust conduit 118. The exhaust manifold 116 is configured to route an exhaust gas stream from the engine to the exhaust conduit 118. More specifically, the exhaust manifold 116 is configured to route an exhaust gas stream from each of the cylinders 104 to the exhaust conduit 118. The exhaust conduit 118 is configured to route the exhaust gas stream from the exhaust manifold 116 to a downstream component, such as the aftertreatment system 120 and/or the turbo device 122. In some embodiments, a first portion of the exhaust conduit 118 is disposed between the exhaust manifold 116 and turbo device 122. The first portion of the exhaust conduit 118 is configured to route the exhaust gas stream from the exhaust manifold 116 to turbo device 122. In some embodiments, a second portion of the exhaust conduit 118 is disposed between the aftertreatment system 120 and the turbo device 122. The second portion of the exhaust conduit 118 is configured to route the exhaust gas stream from the turbo device 122 to the aftertreatment system 120.

[0033] The aftertreatment system 120 is in exhaust gas receiving communication with the engine 102. The aftertreatment system 120 includes components used to reduce exhaust emissions, such as a selective catalytic reduction (SCR) catalyst, an oxidation catalyst (OC), a particulate filter (PF), an exhaust fluid doser with a supply of exhaust fluid, a plurality of sensors for monitoring the aftertreatment system (e.g., a nitrogen oxide (NOx) sensor, temperature sensors, etc.), and/or still other components.

[0034] The turbo device 122 may be any type of turbo machinery, such as a turbocharger, a variable geometry turbocharger, a power turbine, etc. The turbo device 122 may be operatively coupled to the engine 102 and/or another component of the system 100, such as a drivetrain, a battery, an electric machine, or other suitable component. In some embodiments, the turbo device 122 is configured to compress a gas stream (e.g., an intake gas stream, an exhaust gas stream, etc.) and provide the compressed gas stream to the engine 102. For example, as shown in FIG. 1, the turbo device 122 may be coupled to the intake manifold 112 such that the turbo device is operative to provide the compressed gas stream to the engine 102 (e.g., via the intake manifold 112).

[0035] In some embodiments, the system 100 includes an exhaust gas recirculation (EGR) system 150. The EGR system 150 is a system of conduits, heat exchangers, and other components that is configured to route exhaust gases from the exhaust manifold 116 to the intake manifold 114. The EGR system 150 is coupled to the exhaust manifold 116 and the intake manifold 114. The EGR system 150 is in exhaust gas receiving communication with the exhaust manifold 116. The EGR system 150 is in exhaust gas providing communication with the intake manifold 112. According to one embodiment, the EGR system 150 includes one or more conduits that define an EGR circuit 156 that defines a flow path for recirculating exhaust gas (referred to herein as EGR gas). The EGR circuit 156 is structured to route the EGR gas from the exhaust manifold 116 to the intake manifold 114. In one embodiment, the EGR system 150 includes an exhaust throttle structured to modulate (e.g., control, etc.) the exhaust flow through the EGR system 150. The EGR system 150 is described in greater detail herein with respect to FIG. 2.

[0036] In some embodiments, the system 100 includes a waste heat recovery (WHR) system 160. The WHR system 160 is coupled to (e.g., in exhaust gas receiving communication with, etc.) the engine 102. More specifically, at least a portion of the WHR system 160 is disposed downstream of the engine 102, such that the WHR system 160 can selectively receive exhaust gas from the engine 102.

[0037] According to one embodiment, the WHR system 160 is a Rankine cycle waste heat recovery system. The WHR system 160 may also be an organic Rankine cycle waste heat recovery system if a working fluid of the system is an organic high molecular mass fluid having a liquid-vapor phase change that is lower than the water-steam phase change. Examples of organic and inorganic Rankine cycle working fluids include Genetron® R-245fa made by Honeywell, Therminol®, Dowtherm J™ made by Dow Chemical Co., Fluorinol® made by American Nickeloid, toluene, dodecane, isododecane, methylundecane, neopentane, neopentane, octane, water/methanol mixtures, or steam, among other alternatives.

[0038] In an example embodiment, the WHR system 160 is configured to receive exhaust gas from the engine 102 (e.g., via the exhaust conduit 118). In some embodiments, a valve 162 (e.g., a three-way valve) is disposed between the engine 102 and at least a portion of the WHR system 160. In some embodiments the WHR system 160 includes the valve 162.

[0039] The valve may be positioned in line with the exhaust conduit 118, such that a first portion 123 of the exhaust conduit 118 is disposed upstream of the valve 162 and a second portion 124 of the exhaust conduit 118 is disposed downstream of the valve 162. The valve 162 is configured to route exhaust gas from the engine 102 to one or both of the aftertreatment system 120 and at least a portion of the WHR system 160. The valve 162 is operable between a first position and a second position. In the first position, the valve 162 routes exhaust gas from the engine 102 to the aftertreatment system 120, via second portion 124 of the exhaust conduit 118. In the second position, the valve 162 routes exhaust gas from the engine 102 to at least a portion of the WHR system 160. The valve 162 is operable to be positioned in a plurality of positions between the first position and the second position. When the valve 162 is in a position between the first position and the second position, the valve 162 may route a first portion of the exhaust gas to the aftertreatment system 120 and a second portion of the exhaust gas to at least a portion of the WHR system 160. In this way, the valve 162 is structured to selectively direct the exhaust gas to flow to the aftertreatment system 120, the WHR system 160, or both.

[0040] According to one embodiment, the WHR system 160 includes one or more conduits that define an WHR circuit 165 that defines a flow path for a working fluid, such as a coolant. The WHR circuit 165 is structured to route the working fluid from at least a portion of the WHR system 160 to the EGR system 150. The WHR circuit 165 is also structured to route the working fluid from the EGR system 150 to another portion of the WHR system 160. The WHR system 160 is structured to heat the working fluid (e.g., by facilitating heat transfer from the exhaust gas to the working fluid) and use the heated working fluid to generate power. The WHR system 160 may output the power as mechanical power to rotate the shaft 126 and/or electrical power to electrically power the electric machine 128. The WHR system 160 is described in greater detail herein with respect to FIG. 2.

[0041] As shown, a plurality of sensors 125 are included in the system 100. The number, placement, and type of sensors included in the system 100 is shown for example purposes only. That is, in other configurations, the number, placement, and type of sensors may differ. The sensors 125 may be gas constituent sensors (e.g., NOx sensors, oxygen sensors, H2O/humidity sensors, hydrogen sensors, etc.), temperature sensors, particulate matter (PM) sensors, flow rate sensors (e.g., mass flow rate sensors, volumetric flow rate sensors, etc.), other exhaust gas emissions constituent sensors, pressure sensors, some combination thereof, and so on. In an example embodiment, the sensors 125 are configured as temperature sensors configured to acquire data regarding a temperature of a fluid, such as exhaust gas, air, the working fluid, or other fluid in the system 100 and/or acquire data regarding a temperature of a component of the system 100, such as one or more components of the aftertreatment system 120.

[0042] As shown in FIG. 1, the sensors 125 may be located at or proximate the intake conduit 110, the intake manifold 112, the exhaust manifold 116, the exhaust conduit 118, and/or the aftertreatment system 120. For example, the system 100 may include sensors 125 located both before (e.g., upstream) and after (e.g., downstream) the aftertreatment system 120. In another example embodiment, at least one sensor may be located at or proximate the turbo device 122. It should be understood that the location of the sensors may vary, and the system 100 may include more or fewer sensors than as shown in FIG. 1.

[0043] Additional sensors may be also included with the system 100. The sensors may include engine-related sensors (e.g., torque sensors, speed sensors, pressure sensors, flowrate sensors, temperature sensors, etc.). The sensors may further include sensors associated with other components of the vehicle, such as the aftertreatment system 120 or the turbo device 122. For example, the sensor may include speed sensor of the turbo device 122, a fuel quantity and injection rate sensor, fuel rail pressure sensor, etc.).

[0044] The sensors 125 may be real or virtual (i.e., a non-physical sensor that is structured as program logic in the controller 140 that makes various estimations or determinations). For example, an engine speed sensor may be a real or virtual sensor arranged to measure or otherwise acquire data, values, or information indicative of a speed of the engine 102 (typically expressed in revolutions-per-minute). The sensor is coupled to the engine (when structured as a real sensor) and is structured to send a signal to the controller 140 indicative of the speed of the engine 102. When structured as a virtual sensor, at least one input may be used by the controller 140 in an algorithm, model, lookup table, etc. to determine or estimate a parameter of the engine (e.g., power output, etc.). Any of the sensors 125 described herein may be real or virtual.

[0045] As utilized herein, the term “estimating” and like terms are used to refer to determining an approximate current or past value based on data (e.g., sensor data, historical sensor data, real-time sensor data, etc.), which may be close but not necessarily exactly the actual value of the determined current or past parameter value. In some embodiments, estimating the current or past value can be performed using one or more models (e.g., statistical models, artificial intelligence models, machine learning models, etc.). For example, estimating a temperature of an exhaust gas can include using data, such as sensor data, with a model to determine the temperature value. As utilized herein, the term “measuring” and like terms are used to refer to determining an approximate current or past parameter value based on detecting or receiving information regarding the parameter (e.g., using a sensor). The measured value may be close but not necessarily exactly the actual value of the measured current or past parameter value.

[0046] As utilized herein, the term “operational data” and like terms are used to refer to data regarding the operation of a system, such as an engine system. In some embodiments, operational data may include settings, values, or other information regarding the operation of a system. In some embodiments, the operational data may be measured (e.g., by one or more real sensors 125), estimated (e.g., by one or more virtual sensors 125 or by a computer device or processing circuit), and/or otherwise determined. The sensors 125 may be configured to acquire the operational data.

[0047] The controller 140 is coupled, and particularly communicably coupled, to the sensors 125. Accordingly, the controller 140 is structured to receive data from one more of the sensors 125 and provide instruct! ons/informati on to the one or more sensors 125. The received data may be used by the controller 140 to control one more components in the system 100 as described herein.

[0048] As briefly described above, the system 100 includes a shaft 126. In an example embodiment, the shaft 126 is a crankshaft. In other embodiments, the shaft 126 may be any shaft coupled directly or indirectly to the engine 102 such that the shaft is rotated by the engine 102. For example, the shaft 126 may be an output shaft, a drive shaft, a crankshaft, or other suitable shaft. The shaft 126 is configured to transmit power output by the engine 102 to another component, such as an axle, a wheel, or another shaft. In some embodiments an intermediate component couples the engine 102 to the shaft 126, such as a clutch, a transmission, etc. [0049] As briefly described above, the system 100 includes the electric machine 128. The electric machine 128 is configured to use electrical power (e.g., from a battery, an alternator, or the WHR system 160) to output mechanical power. For example, the electric machine 128 is coupled to the shaft 126 such that the shaft 126 is operable to receive power output by the electric machine 128. In this way, the electric machine 128 is operable to rotate shaft 126.

[0050] The operator input/output (I/O) 130 device may be coupled to the controller 140, such that information may be exchanged between the controller 140 and the I/O device, where the information may relate to one or more components of FIG. 1 or determinations (described below) of the controller 140. The operator I/O device enables an operator of the system 100 to communicate with the controller 140 and one or more components of the system 100 of FIG. 1. For example, the operator input/output device may include, but is not limited to, an interactive display, a touchscreen device, one or more buttons and switches, voice command receivers, etc. In this way, the operator input/output device may provide one or more indications or notifications to an operator, such as a malfunction indicator lamp (MIL), etc. Additionally, the vehicle may include a port that enables the controller 140 to connect or couple to a scan tool so that fault codes and other information regarding the vehicle may be obtained.

[0051 ] The controller 140 is structured to control, at least partly, the operation of the system 100 and associated sub-systems, such as the engine 102 and the operator I/O device 130. Communication between and among the components may be via any number of wired or wireless connections. For example, a wired connection may include a serial cable, a fiber optic cable, a CAT5 cable, or any other form of wired connection. In comparison, a wireless connection may include the Internet, Wi-Fi, cellular, radio, etc. In one embodiment, a controller area network (CAN) bus provides the exchange of signals, information, and/or data. The CAN bus includes any number of wired and wireless connections. Because the controller 140 is communicably coupled to the systems and components of FIG. 1, the controller 140 is structured to receive data from one or more of the components shown in FIG. 1. The structure and function of the controller 140 is further described in regard to FIG. 3. [0052] In some embodiments, the controller 140 is configured to provide hydrogen to the exhaust gas by controlling the operation of the engine 102. For example, the controller 140 may prevent combustion of hydrogen fuel in the engine 102 by disabling an ignitor (e.g., a spark plug). The uncomposed hydrogen fuel may flow out of the engine 102 with the exhaust gas, via the exhaust conduit 118.

[0053] In some embodiments, the system 100 includes a hydrogen doser 135. The hydrogen doser 135 is located the second portion 124 of the exhaust conduit 118, downstream of the valve 162 and upstream of the aftertreatment system 120. The hydrogen doser 135 includes one or more components for providing hydrogen (H2) to the exhaust gas stream. For example, the hydrogen doser 135 may include a nozzle, a pump, a fluid conduit, a fluid source (e.g., a hydrogen source), and/or other suitable components for providing hydrogen to the exhaust gas. In some embodiments, the fluid source is the same as a fuel source for the engine 102. The controller 140 may provide hydrogen to the exhaust gas by controlling the operation of the hydrogen doser 135.

[0054] The hydrogen doser 135 is configured to provide hydrogen (H2) to the exhaust gas stream upstream of the aftertreatment system 120. In some embodiments, the hydrogen is provided to the aftertreatment system 120 or one or more components thereof, such as the SCR catalyst. The amount of hydrogen provided to the exhaust gas may be modulated and controlled based on one or more operational parameters, such as a temperature value (e.g., a temperature of the exhaust gas in or proximate the aftertreatment system 120, a temperature of a component of the aftertreatment system 120, etc.) and/or an exhaust gas constituent value (e.g., a NOx value in or proximate the aftertreatment system 120, an O2 value in or proximate the aftertreatment system 120, etc.). The temperature value and/or the exhaust gas constituent value may be received (e.g., by the controller 140 and/or the hydrogen doser 135) from one or more sensors. The sensors may be real sensors that measure the temperature value and/or the exhaust gas constituent value and/or virtual sensors that estimate the temperature value and/or the exhaust gas constituent value. In an example embodiment, the hydrogen doser 135 is configured to provide hydrogen to the exhaust gas when the temperature value is at or below a predetermined threshold. In another example embodiment, the hydrogen doser 135 is configured to provide hydrogen to the exhaust gas when the exhaust gas constituent value is at or above a predetermined threshold.

(0055] In some embodiments, when the system 100 includes the hydrogen doser 135, the controller 140 is configured to provide hydrogen to the exhaust gas by controlling the operation of at least one of the engine 102 or the hydrogen doser 135. In some embodiments, the system 100 does not include the hydrogen doser 135. In these embodiments, the controller 140 is configured to provide hydrogen to the exhaust gas by controlling the operation of the engine 102.

(0056] As the components of FIG. 1 are shown to be embodied in the system 100, the controller 140 may be structured as one or more electronic control units (ECUs), such as one or more microcontrollers. The controller 140 may be separate from or included with at least one of a transmission control unit, an exhaust aftertreatment control unit, a powertrain control module, an engine control unit, an engine control module, etc.

(0057] Now referring to FIG. 2, a schematic diagram of the EGR system 150 and the WHR system 160 of the system of FIG. 1 is shown, according to an example embodiment. As described above, the EGR system 150 may receive EGR gas from the engine 102 via the exhaust manifold 116 and route the EGR gas to the intake manifold 112. The WHR system 160 may receive exhaust gas from the engine 102 via the exhaust conduit 118 and rout the exhaust gas to the aftertreatment system via the second portion of the exhaust conduit 118.

(0058] Referring first to the EGR system 150, the EGR system 150 includes an EGR boiler 152 and an EGR superheater 154. The EGR boiler 152 may be structured to regulate the temperature of an EGR gas by transferring heat from the EGR gas to the working fluid of WHR system 160. It will be appreciated that the term “EGR boiler” is used for convenience only and in no way is meant as limiting. The EGR boiler 152 may further be structured to cool the EGR gas and transfer heat from the EGR gas to the working fluid of WHR system 160. The EGR superheater 154 transfers additional heat energy from the EGR gas to the working fluid, which may be in a gaseous state when it enters the EGR superheater 154. [0059] The EGR superheater 154 and the EGR boiler 152 are connected to a portion of the EGR circuit 156. EGR gas flows along the EGR circuit 156 into the EGR superheater 154 and then downstream from EGR superheater 154 into the EGR boiler 152. From the EGR boiler 152, the EGR gas flows downstream along the EGR circuit 156 to the intake manifold 112. The EGR superheater 154 and the EGR boiler 152 serve as heat exchangers for the EGR circuit 156, facilitating a heat transfer function for the EGR gas flowing through EGR superheater 154 and EGR boiler 152. The EGR superheater 154 and the EGR boiler 152 also serve as heat exchangers for the WHR circuit 165. For example, the EGR superheater 154 and the EGR boiler 152 may be structured to facilitate transferring heat from the EGR gas to the working fluid flowing through the EGR boiler 152 and the EGR superheater 154 to increase. In an example embodiment, the superheater 154 is positioned upstream of the boiler 152. For example, the EGR circuit 156 may route the EGR gas from the exhaust manifold 116 and to the superheater 154. The EGR circuit 156 may route the EGR gas from the superheater 154 to the boiler 152. EGR circuit 156 may route the EGR gas from the boiler 152 to the intake manifold 112.

[0060] With respect to the WHR circuit 165, the superheater is positioned downstream of the boiler 152. For example, the WHR circuit 165 may route the working fluid from a component of the WHR system 160 to the boiler 152 and form the boiler 152 to the superheater 154. The WHR circuit 165 may then route the working fluid to another component of the WHR system 160.

[0061] Referring still to FIG. 2, the WHR system 160 includes a heat exchanger 164, an energy conversion system 166, a recuperator 170, a condenser 172, and a pump 174. In some embodiments, the WHR system 160 also includes a regulator or valve 176. The WHR circuit 165 includes various conduits, pipes, or other components for routing a working fluid to and from each of the components of the WHR system 160. For example, the WHR circuit 165 includes various flow paths for a working fluid to flow between the various components of the WHR system 160 and/or components of the EGR system 150.

[0062] According to an example embodiment, the heat exchanger 164 facilitates heat transfer from the exhaust gas to the working fluid. In this way the heat exchanger 164 facilitates cooling of the exhaust gas. The cooling of the exhaust gas may also cool (e.g., reduce the temperature of) one or more components of the system positioned downstream of the WHR system 160, such as one or more components of the aftertreatment system 120. The heat exchanger 164 also facilitates heating (e.g., increasing the temperature of) the working fluid to permit the working fluid to drive the energy conversion system 166, thereby extracting useful work or energy from the waste heat (e.g., of the exhaust gas, etc.) created by the engine 102.

[0063] The heat exchanger 164 is structured to control the transfer of heat from the exhaust gas of the engine 102 to the working fluid. The amount of heat (i.e., exhaust flow) available to the heat exchanger 164 may be at least partially determined by the valve 162. For example, as the valve 162 is operated from the first position towards the second position, more exhaust gas may flow to the heat exchanger 164.

[0064] The heat exchanger 164 fluidly connects the first portion 123 of the exhaust conduit 118 to the second portion 124 of the exhaust conduit 118. In this way, the heat exchanger 164 may route exhaust gas from the engine 102 to the aftertreatment system 120. The valve 162 is positioned between the first portion 123 of the exhaust conduit 118 and the second portion 124 of the exhaust conduit 118. Both the valve 162 and the heat exchanger 164 are fluidly connected on their downstream sides by the second portion 124 of the exhaust conduit 118 to the aftertreatment system 120.

[0065] With respect to the WHR circuit 165, the heat exchanger 164 is positioned upstream of the EGR system 150. For example, the WHR circuit 165 may route the working fluid from heat exchanger 164 to the boiler 152. The WHR circuit 165 may also route the working fluid from a component upstream of the heat exchanger 164 to the heat exchanger 164.

[0066] The WHR system 160 may include or be coupled to the energy conversion system 166. The energy conversion system may receive the working fluid from the EGR superheater 154. In an example embodiment, the superheated gaseous working fluid flows from the EGR superheater 154 into the energy conversion system 166. The flow of the working fluid through the energy conversion system 166 extracts heat energy. In some embodiments, the heat energy may be used by the energy conversion system 166 to transfer energy to another system or device. In an example embodiment, the energy conversion system 166 is structured to produce work or transfer energy to another device or system (e.g., the engine 102, the shaft 126, the electric machine 128, etc.). The energy conversion system 166 may be or include a turbine, piston, scroll, screw, or other type of expander device that rotates or otherwise moves as a result of an interaction with working fluid. For example, in the embodiment shown in FIG. 2, the energy conversion system 166 includes a turbine 167 and a gear train 168. The turbine 167 is rotated by a pressure exerted by the working fluid flowing through the energy conversion system 166. The turbine 167 rotates the gear train 168. The gear train 168 outputs mechanical energy to another component of the system 100, such as the shaft 126 or the electric machine 128. In this way, the energy conversion system 166 may facilitate rotation of the shaft 126. Additionally and/or alternatively, the energy conversion system 166 may facilitate rotating the electric machine 128 (e.g., to produce electrical power).

[0067] The energy conversion system 166 is positioned along the WHR circuit 165. The energy conversion system 166 is poisoned downstream from the EGR system 150. The energy conversion system 166 is positioned upstream of the recuperator 170.

[0068] The recuperator 170 is positioned along the WHR circuit 165 between the energy conversion system 166 and the condenser 172. The recuperator 170 is positioned downstream of the energy conversion system 166 and upstream of the condenser 172. The WHR circuit 165 also connects the recuperator 170 to the heat exchanger 164. The WHR circuit 165 also connects the recuperator 170 to the EGR system 150. In this way, the working fluid may be selectively routed to the condenser 172, the EGR system 150 or the heat exchanger 164 (e.g., by the recuperator 170).

[0069] The condenser 172 is structured to convert gaseous working fluid to liquid working fluid. The condenser 172 may be or include a sub-cooler that cools the working fluid. The condenser 172 is positioned along the WHR circuit 165 between the recuperator and the pump 174. The condenser 172 is positioned downstream of the recuperator 170 and upstream of the pump 174.

[0070] The pump 174 is positioned along the WHR circuit 165 downstream from the condenser 172 and upstream from the recuperator 170. According to an example embodiment, the pump 174 is coupled to (e.g., driven by, etc.) the engine 102. Thus, the pump speed, and resultant flow rate of working fluid from the pump 174, may be based on the engine speed. In some embodiments, the pump 174 is a self-driven pump (e.g., includes an electric motor, etc.). The resultant flow rate of working fluid from the pump 174 may be modulated by the controller 140 based on operational needs of the WHR system 160.

[00711 In some embodiments, the WHR system 160 includes a valve 176 (e.g., a three-way valve) is disposed along the WHR circuit downstream of the recuperator 170 and upstream of the heat exchanger 164 and the EGR system 150. The valve 176 is configured to route the working fluid from the recuperator to one or both of the EGR system 150 and the heat exchanger 164. The valve 176 is operable between a first position and a second position. In the first position, the valve 176 routes working fluid from the recuperator 170 to the heat exchanger 164. In the second position, the valve 176 routes exhaust gas from the recuperator 170 to the EGR system 150, or, more specifically, the boiler 152. The valve 176 is operable to be positioned in a plurality of positions between the first position and the second position. When the valve 176 is in a position between the first position and the second position, the valve 176 may route a first portion of the working fluid to the heat exchanger 164 and a second portion of the working fluid to the EGR system 150.

[0072] Now referring to FIG. 3, a schematic diagram of the controller 140 of the system 100 of FIG. 1 is shown, according to an example embodiment. As shown, the controller 140 includes at least one processing circuit 202 having at least one processor 204 and at least one memory device 206, WHR circuit 212, and a communications interface 216. The controller 140 is structured to control operation of the WHR system 160. In some embodiments, the controller 140 may control operation of the WHR system 160 to achieve a desired or target temperature of the aftertreatment system 120 and/or a component thereof, such as an SCR catalyst. For example, the controller 140 may operate one or more valves, motors, actuators, or other suitable devices to direct exhaust gas to flow to the heat exchanger 164 of the WHR system 160 to facilitate exchanging heat form the exhaust gas to the working fluid of the WHR system 160. In this way, the controller 140 may facilitate cooling the exhaust gas, thereby cooling components of the system downstream of the WHR system 160, such as the aftertreatment system 120 and/or components thereof. Specific processes for cooling the exhaust gas via the WHR system 160 are described herein below. [0073] In one configuration, the WHR circuit 212 is embodied as machine or computer- readable media storing instructions that are executable by a processor, such as processor 204. As described herein and amongst other uses, the machine-readable media facilitates performance of certain operations to enable reception and transmission of data. For example, the machine-readable media may provide an instruction (e.g., command, etc.) to, e.g., acquire data. In this regard, the machine-readable media may include programmable logic that defines the frequency of acquisition of the data (or, transmission of the data). The computer readable media instructions may include code, which may be written in any programming language including, but not limited to, Java or the like and any conventional procedural programming languages, such as the "C" programming language or similar programming languages. The computer readable program code may be executed on one processor or multiple remote processors. In the latter scenario, the remote processors may be connected to each other through any type of network (e.g., CAN bus, etc.).

[0074] In another configuration, the WHR circuit 212 is embodied as a hardware unit, such as one or more electronic control units. As such, the WHR circuit 212 may be embodied as one or more circuitry components including, but not limited to, processing circuitry, network interfaces, peripheral devices, input devices, output devices, sensors, etc. In some embodiments, the WHR circuit 212 may take the form of one or more analog circuits, electronic circuits (e.g., integrated circuits (IC), discrete circuits, system on a chip (SOCs) circuits, microcontrollers, etc.), telecommunication circuits, hybrid circuits, and any other type of “circuit.” In this regard, the WHR circuit 212 may include any type of component for accomplishing or facilitating achievement of the operations described herein. For example, a circuit as described herein may include one or more transistors, logic gates (e.g., NAND, AND, NOR, OR, XOR, NOT, XNOR, etc.), resistors, multiplexers, registers, capacitors, inductors, diodes, wiring, and so on. The WHR circuit 212 may also include or be programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like. The WHR circuit 212 may include one or more memory devices for storing instructions that are executable by the processor(s) of the WHR circuit 212. The one or more memory devices and processor(s) may have the same definition as provided below with respect to the memory device 206 and processor 204. In some hardware unit configurations, the WHR circuit 212 may be geographically dispersed throughout separate locations in the vehicle. Alternatively, and as shown, the WHR circuit 212 may be embodied in or within a single unit/housing, which is shown as the controller 140.

[0075] In the example shown, the controller 140 includes the at least one processing circuit 202 having the at least one processor 204 and the at least one memory device 206. The processing circuit 202 may be structured or configured to execute or implement the instructions, commands, and/or control processes described herein with respect to the WHR circuit 212. The depicted configuration represents the WHR circuit 212 as being embodied as machine or computer-readable media storing instructions (which may be stored by the memory device 206). However, as mentioned above, this illustration is not meant to be limiting as the present disclosure contemplates other embodiments where the WHR circuit 212, is configured as a hardware unit. All such combinations and variations are intended to fall within the scope of the present disclosure.

[0076] The processor 204 may be implemented as one or more single- or multi-chip processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), and/or suitable processors (e.g., other programmable logic devices, discrete hardware components, etc. to perform the functions described herein). A processor may be a microprocessor, a group of processors, etc. A processor also may be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some embodiments, the one or more processors may be shared by multiple circuits (e.g., the WHR circuit 212 may comprise or otherwise share the same processor which, in some example embodiments, may execute instructions stored, or otherwise accessed, via different areas of memory). Alternatively or additionally, the one or more processors may be structured to perform or otherwise execute certain operations independent of one or more co-processors. In other example embodiments, two or more processors may be coupled via a bus to enable independent, parallel, pipelined, or multi-threaded instruction execution. All such variations are intended to fall within the scope of the present disclosure. [0077] The memory device 206 (e.g., memory, memory unit, storage device) may include one or more devices (e.g., RAM, ROM, Flash memory, hard disk storage) for storing data and/or computer code for completing or facilitating the various processes, layers and modules described in the present disclosure. For example, the memory device 206 may include dynamic random-access memory (DRAM). The memory device 206 may be communicably connected to the processor 204 to provide computer code or instructions to the processor 204 for executing at least some of the processes described herein. Moreover, the memory device 206 may be or include tangible, non-transient volatile memory or non-volatile memory. Accordingly, the memory device 206 may include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described herein.

[0078] The communications interface 216 may include any combination of wired and/or wireless interfaces (e.g., jacks, antennas, transmitters, receivers, transceivers, wire terminals) for conducting data communications with various systems, devices, or networks structured to enable in-vehicle communications (e.g., between and among the components of the vehicle) and out-of-vehicle communications (e.g., with a remote server). For example, and regarding out-of-vehicle/system communications, the communications interface 216 may include an Ethernet card and port for sending and receiving data via an Ethernet-based communications network and/or a Wi-Fi transceiver for communicating via a wireless communications network. The communications interface 216 may be structured to communicate via local area networks or wide area networks (e.g., the Internet) and may use a variety of communications protocols (e.g., IP, LON, Bluetooth, ZigBee, radio, cellular, near field communication).

[0079] As shown in FIG. 3, the communications interface 216 may enable communication with the engine 102, the aftertreatment system 120 (and/or a component thereof), the one or more sensors 125, the EGR system 150 and/or the WHR system 160. In some embodiments, the communications interface 216 may enable communication with the electric machine 128.

[0080] The WHR circuit 212 is structured to enable or a cause at least a portion of exhaust gas produced by the engine 102 to flow to at least a portion of the WHR system 160. In some embodiments, the controller 140 may receive temperature data regarding one or more components of the system 100 and/or the exhaust gas flowing therethrough. The temperature data may be or include, for example, one or more temperature values regarding the aftertreatment system 120, the turbo device 122, and/or the exhaust gas. In some embodiments, the temperature data is indicative of a first temperature value of the aftertreatment system 120, such as a temperature of a component of the aftertreatment system 120, a temperature of exhaust gas in the aftertreatment system 120, or other temperature value of the aftertreatment system 120, components thereof, or exhaust gases therein. In some embodiments, the first temperature value of the aftertreatment system, is a temperature of a component of the aftertreatment system 120, such as the SCR catalyst. In some embodiments, the temperature data is indicative of a second temperature value corresponding to a temperature of the exhaust gas at or proximate an inlet of the aftertreatment system 120 and a third temperature value corresponding to a temperature of the exhaust gas at or proximate an outlet of the aftertreatment system 120. In some embodiments, the controller 140 may use the second temperature value and the third temperature value to determine the first temperature value of a component of the aftertreatment system 120. For example, the controller 140 may use one or more of a lookup table or a model (e.g., a mathematical model, a statistical model, a machine learning model, etc.) to estimate a temperature value of the component of the aftertreatment system 120. In an example embodiment, the first temperature value (e.g., the temperature of a component of the aftertreatment system 120) may be an average (e.g., mean) value of the first temperature value corresponding to the temperature of the exhaust gas at or proximate an inlet of the aftertreatment system 120 and the second temperature value corresponding to the temperature of the exhaust gas at or proximate an outlet of the aftertreatment system 120. In some embodiments, the component of the aftertreatment system 120 is a catalyst member, such as a SCR catalyst member. In other embodiments, the component of the aftertreatment system 120 is a different type of catalyst member (e.g., an oxidation catalyst member), a filter (e.g., a particulate filter), or other suitable component of the aftertreatment system 120.

[0081] In some embodiments, the temperature data may be or include one or more operational parameters other than a temperature value. For example, the temperature data may include one or more operational parameters that may be used to estimate a temperature value. The one or more operational parameters may include, for example, one or more exhaust gas constituent values. The controller 140 may be configured to estimate one or more temperature values based on the exhaust gas constituent values. For example, the temperature data may include a first NOx value regarding a NOx content in the exhaust gas upstream of the aftertreatment system 120 and a second NOx value regarding a NOx content in the exhaust gas downstream of the aftertreatment system 120. The controller 140 may estimate the one or more temperature values based on the first NOx value and the second NOx value. For example, the controller 140 may use one or more of a model (e.g., a machine learning model, a mathematical model, a statistical model, etc.) or a lookup table that correlates the first NOx value and/or the second NOx value to one or more temperature values. In an example embodiment, a difference (e.g., a percent difference, an absolute difference, etc.) between the first NOx value and the second NOx may correspond to a temperature of one or more components of the aftertreatment system 120.

[0082] The WHR circuit 212 may compare the temperature value to a predetermined temperature threshold. The predetermined temperature threshold may be based on a desired operating temperature or target operating temperature of the aftertreatment system 120 or a component thereof. For example, a component of the aftertreatment system 120, such as an SCR catalyst, may have a desired operating temperature (e.g., a target temperature value or range of values). In some embodiments, the desired operating temperature is 200°C. In other embodiments, the desired operating temperature is a range of temperatures between 200°C and 250 °C, inclusive. In yet other embodiments, the desired operating temperature may be a temperature value or range of temperature values less than 200°C, including 200°C, or greater than 200°C. The predetermined temperature threshold may be equal to the desired operating temperature and/or equal to at least one value of a range of desired operating temperature values.

[0083 As described above, the desired operating temperature of the SCR catalyst in a system with a hydrogen internal combustion engine, such as the engine 102, is less than the desired operating temperature of an SCR catalyst intended for use with a diesel-fueled internal combustion engine. Thus, in any of the above-described embodiments, the desired operating temperature is relatively less than the desired operating temperature of an SCR catalyst intended for use with a diesel-fueled internal combustion engine. [0084] In some embodiments, the controller 140 may iteratively determine the predetermined temperature threshold. For example, the controller 140 may use one or more models, such as a machine learning model, to determine the threshold. In some embodiments, the controller 140 may determine the predetermined temperature threshold based on the desired operating temperature of a component of the aftertreatment system 120, such as the SCR catalyst. In some embodiments, the desired operating temperature of the component of the aftertreatment system 120 changes over time. In these embodiments, the controller 140 may use operational data (e.g., one or more temperature values, one or more NOx values, etc.) received from one or more sensors 125 to determine the desired operating temperature and, in turn, the predetermined temperature threshold.

[0085] The WHR circuit 212 may control the operation of the valve 162 based on comparing the temperature value to the predetermined temperature threshold. In some embodiments, responsive to determining that the temperature value is below the predetermined temperature threshold, the WHR circuit 212 may cause the valve 162 to direct exhaust gas to flow to the aftertreatment system 120. The WHR circuit 212 may also cause the valve 162 to substantially prevent the exhaust gas from flowing to the WHR system 160, or a portion thereof, such as the heat exchanger 164.

[0086] In some embodiments, responsive to determining that the temperature value is at or above the predetermined temperature threshold, the WHR circuit 212 may cause the valve 162 to direct a first portion of the exhaust gas to flow to the aftertreatment system 120. The WHR circuit 212 may also cause the valve 162 to direct a second portion of the exhaust gas to flow to the WHR system 160, or a portion thereof, such as the heat exchanger 164. In this way, the exhaust flow is split between two flow paths. A first flow path is defined between the valve 162 and the aftertreatment system 120, along the second portion 124 of the exhaust conduit 118. The first portion of the exhaust gas may flow along the first flow path. A second flow path is at least partially defined between the valve 162 and the WHR system 160. The second flow path rejoins the first flow path. More specifically, second flow path rejoins the first flow path downstream of the WHR system 160. The second flow path rejoins the first flow path downstream of the valve 162. The second portion of the exhaust gas may flow along the second flow path. [0087] As described above, when the exhaust gas, or at least a portion thereof, flows through the heat exchanger 164, the heat exchanger 164 facilitates heat transfer from the exhaust gas to the working fluid of the WHR system 160. In this way, the portion of the exhaust gas flowing through the heat exchanger 164 is cooled, advantageously cooling a downstream component, such as a SCR catalyst of the aftertreatment system 120.

[0088] In some embodiments, the WHR circuit 212 may continue to cause the valve 162 to direct the second portion of the exhaust gas to flow to the WHR system 160 when the temperature value regarding the aftertreatment system 120 (e.g., the temperature of the SCR catalyst) is at or above the predetermined temperature threshold. For example, the WHR circuit 212 may receive new temperature data. The new temperature data may be or include, for example, one or more temperature values regarding the aftertreatment system 120, such as a temperature of the exhaust gas at an inlet of the aftertreatment system 120, a temperature of the exhaust gas at an outlet of the aftertreatment system 120, a temperature of a component of the aftertreatment system 120, such as the SCR catalyst, and so on. The WHR circuit 212 may compare the new temperature value to the predetermined temperature threshold. The WHR circuit 212 may continue to cause the valve 162 to direct the second portion of the exhaust gas to flow to the WHR system 160 when the new temperature value regarding the aftertreatment system 120 (e.g., the temperature of the SCR catalyst) is at or above the predetermined temperature threshold. The WHR circuit 212 cause the valve 162 to direct the exhaust gas to flow to the aftertreatment system 120 when the new temperature value regarding the aftertreatment system 120 (e.g., the temperature of the SCR catalyst) is below the predetermined temperature threshold.

(0089] In some embodiments, the controller 140 may be configured to modify (e.g., increase or decrease) the temperature threshold. In some embodiments, the controller 140 receives information regarding the temperature threshold, such as the desired operating temperature value or the range of desired operating temperature values. In some embodiments, the desired operating temperature is 200°C. In some embodiments, the desired operating temperature is a range of temperatures between 200 °C and 250 °C. In some embodiments, the desired operating temperature is based on one or more characteristics of the engine 102, such as fuel type, engine displacement, and/or other suitable characteristics. In some embodiments, the desired operating temperature is based on one or more characteristics of the aftertreatment system 120, such as a chemistry of a catalyst (e.g., a SCR catalyst chemistry) and/or other suitable characteristics.

[0090] In some embodiments, the information regarding the temperature threshold includes an expected NOx value of the aftertreatment system 120. A NOx value of the aftertreatment system 120 may include a NOx content at or proximate an inlet of the aftertreatment system 120, a NOx content at or proximate an outlet of the aftertreatment system 120, a NOx content at or proximate an component of the aftertreatment system 120, such as the SCR catalyst, and/or another NOx content value regarding the aftertreatment system 120. The expected NOx value of the aftertreatment system 120 is NOx value that is expected to occur based on the temperature of the aftertreatment system 120, or a component thereof. In some embodiments, the expected NOx value of the aftertreatment system 120 is or includes an expected NOx value for the desired operating temperature value. In some embodiments, the expected NOx value of the aftertreatment system 120 is or includes an expected NOx value for one or more temperature values of the range of desired operating temperature values. In some embodiments, the NOx value is or includes a range of NOx values. Each range of NOx values may correspond to one or more temperature values of the range of desired operating temperature values.

[0091] Together the desired operating temperature values (e.g., temperature target(s)) and the expected NOx value of the aftertreatment system 120 define desired operating conditions. That is, the desired operating conditions occur when the aftertreatment system 120 is operating such that a temperature value of the aftertreatment system 120 and an actual NOx value of the aftertreatment system 120 are equal to a desired temperature value, equal to expected NOx value, within a range of desired temperature values, and/or within a range of expected NOx values. Changes to the aftertreatment system 120 over time, such as degradation of a catalyst member, may cause the aftertreatment system 120 (or a component thereof) to decrease in efficiency. The efficiency of the aftertreatment system 120 (or component thereof) may be measured as a rate at which the aftertreatment system 120 (or component thereof) converts an exhaust gas constituent, such as NOx, to another chemical or chemicals. Thus, a decrease in efficiency means a decrease in the rate of conversion. [0092] Advantageously, the controller 140 may dynamically adjust the desired operating temperature value(s) to account for changes to the aftertreatment system 120 over time. More specifically, the controller 140 may adjust the temperature threshold such that the aftertreatment system 120 operates at the desired operating temperature value and/or within the range of desired operating temperature values. The controller 140 may dynamically adjust the desired operating temperature value(s) and/or the temperature threshold based on operational data regarding the aftertreatment system.

[0093] The controller 140 may receive information regarding a NOx value of the aftertreatment system 120. The information regarding a NOx value of the aftertreatment system 120 may include a NOx content at or proximate an inlet of the aftertreatment system 120, a NOx content at or proximate an outlet of the aftertreatment system 120, a NOx content at or proximate an component of the aftertreatment system 120, such as the SCR catalyst, and/or another NOx content value regarding the aftertreatment system 120. In some embodiments, the information regarding a NOx value of the aftertreatment system 120 is received from and measured by a real sensor, such as a NOx sensor, an oxygen sensor, or other sensor configured to acquire data regarding a NOx content in or proximate the aftertreatment system 120. In some embodiments, the information regarding a NOx value of the aftertreatment system 120 is received from and estimated by a virtual sensor that uses one or more of a lookup table or a model (e.g., a machine learning model, a statical model, etc.) that correlates operational data of the system 100 to an estimated NOx value. In some embodiments, the controller 140 may receive temperature data corresponding to the information regarding the NOx value of the aftertreatment system 120. More specifically, each NOx value may correspond to a temperature value of the aftertreatment system 120. The correspondence between the NOx value and the temperature value may be a time value, such as an engine hour value, a timer value, a time of day, etc. For example, each NOx value and corresponding temperature value may both correspond to the same time value.

[0094] The controller 140 may compare the received NOx value and corresponding received temperature value to the expected NOx value and corresponding temperature value. The controller 140 may determine whether to adjust (e.g., increase or decrease) the temperature threshold based on the comparison. [00951 In some embodiments, responsive to determining that (i) the received NOx value are less than the expected NOx value(s) at the desired operating temperature value or range of operating temperature values and (ii) the received temperature values are different than the desired operating temperature value or range of operating temperature values, the controller 140 may adjust (e.g., increase or decrease) the temperature threshold. In an example embodiment, responsive to determining that the (i) the received NOx value are less than the expected NOx value(s) at the desired operating temperature value or range of operating temperature values and (ii) the received temperature values are greater than the desired operating temperature value or range of operating temperature values, the controller 140 may increase the temperature threshold. In another example embodiment, responsive to determining that the (i) the received NOx value are less than the expected NOx value(s) at the desired operating temperature value or range of operating temperature values and (ii) the received temperature values are less than the desired operating temperature value or range of operating temperature values, the controller 140 may decrease the temperature threshold.

[0096] In this way, the controller 140 may modify the temperature threshold to account for changes in the aftertreatment system component(s), such as the SCR catalyst, over time. Advantageously, modifying the temperature threshold may result in the aftertreatment system component(s), such as the SCR catalyst, to convert NOx to other chemical at a greater rate compared to conventional systems.

[0097] Now referring to FIG. 4, a flow diagram of a method 300 of operating the WHR system 160 is shown, according to an example embodiment. In particular, the controller 140, or a component thereof such as the WHR circuit 212, is structured to operate the WHR system 160.

[0098] At process 302, the controller 140 receives temperature data. As described above, the temperature data may be or include a temperature value regarding the aftertreatment system 120. For example, the temperature data may include a temperature of the exhaust gas at an inlet of the aftertreatment system 120, a temperature of the exhaust gas at an outlet of the aftertreatment system 120, a temperature of a component of the aftertreatment system 120, such as the SCR catalyst, and so on. In some embodiments, the controller 140 may determine the temperature value based on the temperature data. For example, the controller 140 may determine a temperature of a component of the aftertreatment system 120 based on a temperature of the exhaust gas at an inlet of the aftertreatment system 120 and a temperature of the exhaust gas at an outlet of the aftertreatment system 120. At process 304, the controller 140 compares the temperature value to a predetermined temperature threshold.

[0099] At process 306, the controller 140 causes exhaust gas to flow to the WHR system 160, responsive to determining that the temperature value is at or above the predetermined temperature threshold. The controller 140 causes exhaust gas to flow to the WHR system 160, responsive to the temperature value being at or above the predetermined temperature threshold. For example, the controller 140 may operate the valve 162 to direct the exhaust gas to flow to the WHR system 160. In some embodiments, the controller 140 causes the entirety of the exhaust gas to flow to the WHR system 160. In other embodiments, and as described above, the controller 140 may cause at least a portion of the exhaust gas to flow to the WHR system 160. In this way, a first portion of the exhaust gas flows to the aftertreatment system 120, and a second portion of the exhaust gas flows to the WHR system 160.

[0100] At process 308, the controller 140 causes exhaust gas to flow to the aftertreatment system (ATS) 120, responsive to determining that the temperature value is below the predetermined temperature threshold. The controller 140 causes exhaust gas to flow to the aftertreatment system (ATS) 120 responsive to the temperature value being below the predetermined temperature threshold. For example, the controller 140 may operate the valve 162 to direct the exhaust gas to flow to the aftertreatment system 120.

10101] In some embodiments, the controller 140 may repeat the method 300 (e.g., after process 306 and/or after process 308), returning to process 302. In these embodiments, the controller 140 may receive new temperature data when returning to process 302.

[0102] Now referring to FIG. 5, a flow diagram of a method 400 of adjusting the temperature threshold is shown, according to an example embodiment. In particular, the controller 140, or a component thereof such as the WHR circuit 212, is structured to adjust the temperature threshold, such as the temperature threshold used at process 304 of the method 300. [0103| At process 402, the controller 140 receives information regarding the temperature threshold, such as the desired operating temperature value or the range of desired operating temperature values. In some embodiments, the information regarding the temperature threshold includes an expected NOx value of the aftertreatment system 120. In some embodiments, the expected NOx value of the aftertreatment system 120 is or includes an expected NOx value for the desired operating temperature value. In some embodiments, the expected NOx value of the aftertreatment system 120 is or includes an expected NOx value for one or more temperatures value of the range of desired operating temperature values.

[0104] At process 404, the controller 140 receives information regarding a NOx value of the aftertreatment system 120. In some embodiments, the controller 140 may also receive temperature data corresponding to the information regarding the NOx value of the aftertreatment system 120. More specifically, each received NOx value may correspond to a received temperature value of the aftertreatment system 120.

[0105] At process 406, the controller 140 may compare the received NOx value and corresponding received temperature value to the expected NOx value and corresponding temperature value. At process 408, the controller 140 adjusts (e.g., increase or decrease) the temperature threshold based on the comparison.

[0106] In some embodiments, the controller 140 may increase the temperature threshold responsive to determining that (i) the received NOx value are less than the expected NOx value(s) at the desired operating temperature value or range of operating temperature values and/or (ii) the received temperature values are greater than the desired operating temperature value or range of operating temperature values. The controller 140 may increase the temperature threshold responsive to (i) the received NOx value being below the expected NOx value(s) at the desired operating temperature value or range of operating temperature values and/or (ii) the received temperature values being at or above the desired operating temperature value or range of operating temperature values.

[0107] In some embodiments, the controller 140 may decrease the temperature threshold responsive to determining that (i) the received NOx value are less than the expected NOx value(s) at the desired operating temperature value or range of operating temperature values and (ii) the received temperature values are less than the desired operating temperature value or range of operating temperature values. The controller 140 may decrease the temperature threshold responsive to (i) the received NOx value being below the expected NOx value(s) at the desired operating temperature value or range of operating temperature values and (ii) the received temperature values being below the desired operating temperature value or range of operating temperature values.

[0108] In some embodiments, the controller 140 keeps the temperature threshold the same (e.g., not adjust the threshold) responsive to determining that (i) the received NOx value are less than the expected NOx value(s) at the desired operating temperature value or range of operating temperature values and (ii) the received temperature values are the same as or substantially similar to the desired operating temperature value or range of operating temperature values. The controller 140 keep the temperature threshold the same responsive to determining that (i) the received NOx value(s) are greater than the expected NOx value(s) at the desired operating temperature value or range of operating temperature values and (ii) the received temperature values are different than the desired operating temperature value or range of operating temperature values.

[0109] As utilized herein, the terms “approximately,” “about,” “substantially”, and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the disclosure as recited in the appended claims.

[0110] It should be noted that the term “exemplary” and variations thereof, as used herein to describe various embodiments, are intended to indicate that such embodiments are possible examples, representations, or illustrations of possible embodiments (and such terms are not intended to connote that such embodiments are necessarily extraordinary or superlative examples). [0111 The term “coupled” and variations thereof, as used herein, means the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent or fixed) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members coupled directly to each other, with the two members coupled to each other using one or more separate intervening members, or with the two members coupled to each other using an intervening member that is integrally formed as a single unitary body with one of the two members. If “coupled” or variations thereof are modified by an additional term (e.g., directly coupled), the generic definition of “coupled” provided above is modified by the plain language meaning of the additional term (e.g., “directly coupled” means the joining of two members without any separate intervening member), resulting in a narrower definition than the generic definition of “coupled” provided above. Such coupling may be mechanical, electrical, or fluidic. For example, circuit A communicably “coupled” to circuit B may signify that the circuit A communicates directly with circuit B (i.e., no intermediary) or communicates indirectly with circuit B (e.g., through one or more intermediaries).

[0112] References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below”) are merely used to describe the orientation of various elements in the FIGURES. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure.

[0113] While various circuits with particular functionality are shown in FIG. 3, it should be understood that the controller 140 may include any number of circuits for completing the functions described herein. For example, the activities and functionalities of the WHR circuit 212 may be combined in multiple circuits or as a single circuit. Additional circuits with additional functionality may also be included. Further, the controller 140 may further control other activity beyond the scope of the present disclosure.

[0114] As mentioned above and in one configuration, the “circuits” may be implemented in machine-readable medium for execution by one or more of various types of processors, such as the processor 204 of FIG. 3. Executable code may, for instance, comprise one or more physical or logical blocks of computer instructions, which may, for instance, be organized as an object, procedure, or function. Nevertheless, the executables need not be physically located together, but may comprise disparate instructions stored in different locations which, when joined logically together, comprise the circuit and achieve the stated purpose for the circuit. Indeed, a circuit of computer readable program code may be a single instruction, or many instructions, and may even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data may be identified and illustrated herein within circuits, and may be embodied in any suitable form and organized within any suitable type of data structure. The operational data may be collected as a single data set, or may be distributed over different locations including over different storage devices, and may exist, at least partially, merely as electronic signals on a system or network.

[0115] While the term “processor” is briefly defined above, the term “processor” and “processing circuit” are meant to be broadly interpreted. In this regard and as mentioned above, the “processor” may be implemented as one or more processors, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), digital signal processors (DSPs), or other suitable electronic data processing components structured to execute instructions provided by memory. The one or more processors may take the form of a single core processor, multi-core processor (e.g., a dual core processor, triple core processor, quad core processor, etc.), microprocessor, etc. In some embodiments, the one or more processors may be external to the apparatus, for example the one or more processors may be a remote processor (e.g., a cloud based processor). Alternatively or additionally, the one or more processors may be internal and/or local to the apparatus. In this regard, a given circuit or components thereof may be disposed locally (e.g., as part of a local server, a local computing system, etc.) or remotely (e.g., as part of a remote server such as a cloud based server). To that end, a “circuit” as described herein may include components that are distributed across one or more locations.

[0116] Embodiments within the scope of the present disclosure include program products comprising computer or machine-readable media for carrying or having computer or machine-executable instructions or data structures stored thereon. Such machine-readable media can be any available media that can be accessed by a computer. The computer readable medium may be a tangible computer readable storage medium storing the computer readable program code. The computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable medium may include but are not limited to a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a portable compact disc read-only memory (CD-ROM), a digital versatile disc (DVD), an optical storage device, a magnetic storage device, a holographic storage medium, a micromechanical storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, and/or store computer readable program code for use by and/or in connection with an instruction execution system, apparatus, or device. Machine-executable instructions include, for example, instructions and data which cause a computer or processing machine to perform a certain function or group of functions.

[0117] The computer readable medium may also be a computer readable signal medium. A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electrical, electro-magnetic, magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport computer readable program code for use by or in connection with an instruction execution system, apparatus, or device. Computer readable program code embodied on a computer readable signal medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, Radio Frequency (RF), or the like, or any suitable combination of the foregoing.

[0118] In one embodiment, the computer readable medium may comprise a combination of one or more computer readable storage mediums and one or more computer readable signal mediums. For example, computer readable program code may be both propagated as an electro-magnetic signal through a fiber optic cable for execution by a processor and stored on RAM storage device for execution by the processor.

[0119] Computer readable program code for carrying out operations for aspects of the present disclosure may be written in any combination of one or more other programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The computer readable program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone computer- readable package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0120] The program code may also be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function/act specified in the schematic flowchart diagrams and/or schematic block diagrams block or blocks.

[0121 ] Although the figures and description may illustrate a specific order of method steps, the order of such steps may differ from what is depicted and described, unless specified differently above. Also, two or more steps may be performed concurrently or with partial concurrence, unless specified differently above. Such variation may depend, for example, on the software and hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure. Likewise, software implementations of the described methods could be accomplished with standard programming techniques with rule-based logic and other logic to accomplish the various connection steps, processing steps, comparison steps, and decision steps.

[0122 ] It is important to note that the construction and arrangement of the apparatus and system as shown in the various exemplary embodiments is illustrative only. Additionally, any element disclosed in one embodiment may be incorporated or utilized with any other embodiment disclosed herein.

Claims

WHAT IS CLAIMED IS:

1. A system comprising: an aftertreatment system coupled to a hydrogen internal combustion engine and receiving exhaust gas from the hydrogen internal combustion engine; a waste heat recovery system coupled to the hydrogen internal combustion engine, the waste heat recovery system comprising a heat exchanger; and a controller comprising at least one processor and at least one memory device storing instructions that, when executed by the at least one processor, cause the controller to perform operations comprising: receiving temperature data indicative of a first temperature value of the aftertreatment system; comparing the first temperature value to a predetermined temperature threshold; responsive to determining that the first temperature value is at or above the predetermined temperature threshold, causing at least a portion of the exhaust gas to flow to the heat exchanger of the waste heat recovery system; and responsive to determining that the first temperature value is below the predetermined temperature threshold, causing the exhaust gas to flow to the aftertreatment system.

2. The system of claim 1, wherein the temperature data comprises a second temperature value indicative of a temperature of the exhaust gas at an inlet of the aftertreatment system and a third temperature value indicative of a temperature of the exhaust gas at an outlet of the aftertreatment system; wherein the operations further comprise determining, based on the second temperature value and the third temperature value, the first temperature value.

3. The system of claim 1, further comprising a valve positioned downstream of the hydrogen internal combustion engine and upstream of the heat exchanger and the aftertreatment system, the valve structured to selectively direct the exhaust gas to flow to the aftertreatment system, the waste heat recovery system, or both; wherein causing the portion of the exhaust gas to flow to the heat exchanger of the waste heat recovery system comprises operating the valve to direct the portion of the exhaust gas to flow to the heat exchanger.

4. The system of claim 1, wherein the heat exchanger is disposed upstream of the aftertreatment system, such that the portion of the exhaust gas flows from the heat exchanger to the aftertreatment system.

5. The system of claim 1, further comprising an electric machine coupled to at least a portion of the waste heat recovery system, the electric machine configured to receive power from the waste heat recovery system and generate electrical power.

6. The system of claim 1, wherein the instructions, when executed by the at least one processor, cause the controller to perform further operations comprising: responsive to causing the portion of the exhaust gas to flow to the heat exchanger of the waste heat recovery system, receiving additional data comprising a new temperature value; comparing the new temperature value to the predetermined temperature threshold; responsive to the new temperature value being at or above the predetermined temperature threshold, continuing to cause the portion of the exhaust gas to flow to the heat exchanger; and responsive to the new temperature value being below the predetermined temperature threshold, causing the exhaust gas to flow to the aftertreatment system.

7. The system of claim 1, wherein the first temperature value is at least one of a temperature of a SCR catalyst of the aftertreatment system or a temperature of the exhaust gas in or upstream of the aftertreatment system.

8. The system of claim 1, further comprising a hydrogen doser configured to provide hydrogen to the aftertreatment system, wherein the instructions, when executed by the at least one processor, further cause the controller to perform operations comprising: causing the hydrogen doser to provide the hydrogen to the aftertreatment system responsive to the first temperature value being at or below a second predetermined temperature threshold.

9. A method comprising: receiving temperature data indicative of a first temperature value of an aftertreatment system in exhaust gas receiving communication with an engine; comparing the first temperature value to a predetermined temperature threshold; responsive to the first temperature value being at or above the predetermined temperature threshold, causing at least a portion of the exhaust gas to flow to a heat exchanger to reduce a temperature of the exhaust gas; and responsive to the first temperature value being below the predetermined temperature threshold, causing the exhaust gas to flow to the aftertreatment system.

10. The method of claim 9, wherein: the temperature data comprises a second temperature value indicative of a temperature of the exhaust gas at an inlet of the aftertreatment system and a third temperature value indicative of a temperature of the exhaust gas at an outlet of the aftertreatment system; and the method further comprises determining, based on the second temperature value relative to the third temperature value, the first temperature value.

11. The method of claim 9, wherein causing the portion of the exhaust gas to flow to the heat exchanger comprises operating a valve to direct the portion of the exhaust gas to flow to the heat exchanger, wherein the valve is positioned downstream of the engine and upstream of the heat exchanger and the aftertreatment system, and wherein the valve is structured to selectively direct the exhaust gas to flow to the aftertreatment system, the heat exchanger, or both.

12. The method of claim 9, wherein the heat exchanger is disposed upstream of the aftertreatment system, such that the portion of the exhaust gas flows from the heat exchanger to the aftertreatment system.

13. The method of claim 9, wherein: the temperature data comprises a first NOx value regarding a NOx content in the exhaust gas upstream of the aftertreatment system and a second NOx value regarding the NOx content in the exhaust gas downstream of the aftertreatment system; and the method further comprises determining, based on the first NOx value relative to the second NOx value, the first temperature value.

14. The method of claim 9, further comprising: responsive to causing the portion of the exhaust gas to flow to the heat exchanger, receiving additional data comprising a new temperature value; comparing the new temperature value to the predetermined temperature threshold; responsive to the new temperature value being at or above the predetermined temperature threshold, continuing to cause the portion of the exhaust gas to flow to the heat exchanger; and responsive to the new temperature value being below the predetermined temperature threshold, causing the exhaust gas to flow to the aftertreatment system.

15. A non-transitory computer readable media storing instructions that, when executed by one or more processors, cause the one or more processors to perform operations comprising: receiving temperature data indicative of a first temperature value of an aftertreatment system in exhaust gas receiving communication with a hydrogen internal combustion engine; comparing the first temperature value to a predetermined temperature threshold; responsive to the first temperature value being at or above the predetermined temperature threshold, causing at least a portion of the exhaust gas to flow to a heat exchanger to reduce a temperature of the exhaust gas; and responsive to the first temperature value being below the predetermined temperature threshold, causing the exhaust gas to flow to the aftertreatment system.

16. The non-transitory computer readable media of claim 15, wherein: the temperature data comprises a second temperature value indicative of a temperature of the exhaust gas at an inlet of the aftertreatment system and a third temperature value indicative of a temperature of the exhaust gas at an outlet of the aftertreatment system; and the instructions, when executed by the one or more processors, cause the one or more processors to perform further operations comprising determining, based on the second temperature value relative to the third temperature value, the first temperature value.

17. The non-transitory computer readable media of claim 15, wherein causing the portion of the exhaust gas to flow to the heat exchanger comprises operating a valve to direct the portion of the exhaust gas to flow to the heat exchanger, wherein the valve is positioned downstream of the engine and upstream of the heat exchanger and the aftertreatment system, and wherein the valve is structured to selectively direct the exhaust gas to flow to the aftertreatment system, the heat exchanger, or both.

18. The non-transitory computer readable media of claim 15, wherein the heat exchanger is disposed upstream of the aftertreatment system, such that the portion of the exhaust gas flows from the heat exchanger to the aftertreatment system.

19. The non-transitory computer readable media of claim 15, wherein the instructions, when executed by the one or more processors, cause the one or more processors to perform further operations comprising: responsive to causing the portion of the exhaust gas to flow to the heat exchanger, receiving additional data comprising a new temperature value; comparing the new temperature value to the predetermined temperature threshold; responsive to the new temperature value being at or above the predetermined temperature threshold, continuing to cause the portion of the exhaust gas to flow to the heat exchanger; and responsive to the new temperature value being below the predetermined temperature threshold, causing the exhaust gas to flow to the aftertreatment system.

20. The non-transitory computer readable media of claim 15, wherein the predetermined temperature threshold is between 200 °C and 250 °C, inclusive.