Hybrid power system power control systems and methods

Abstract

A system is configured to receive a power demand, determine a target engine speed based on the power demand, determine an engine speed ramp rate based on a power limit of the energy storage system and the target engine speed, and adjust an engine speed of the internal combustion engine to the determined engine speed at the determined engine speed ramp rate.

Description

Attny Docket No. 106389-9673HYBRID POWER SYSTEM POWER CONTROL SYSTEMS AND METHODSCROSS-REFERENCE TO RELATED PATENT APPLICATION

[0001] This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 745,307, filed on January 14, 2025, which is incorporated herein by reference in its entirety and for all purposes.TECHNICAL FIELD

[0002] The present disclosure relates to extending life in a hybrid vehicle by reducing the engine ramp rate and using power from an energy storage system to provide power to the vehicle during various operating conditions, such as engine ramping.BACKGROUND

[0003] In certain hybrid vehicles, an engine drives an alternator as a main source of electrical power based on power demand, similar to a genset. The electrical power is used to power a motor or motors to turn the wheels and propel the vehicle. In certain cases, hybrid vehicles, such as mine trucks used to transport large amounts of material in mining operations, experience cyclical and immediate demand for power from the engine after periods of relatively low power. For example, when a mine truck is transitioning from a stationary position to an uphill drive with a full load, the engine of a mine truck may need to transition from a low idle speed or a low power operation to rated speed and rated power as fast as possible to provide power to the motors substantially immediately. Similarly, when the mine truck is transitioning back to a stationary position after being driven, the engine may need to ramp back down to low power and / or idle speed to avoid overproducing power that is not needed to operate the truck. Over the course of a day, the engine may have to cycle between idle speed and / or low power points and full load several times. The rate at which the engine ramps up from idle speed to full speed and vice versa, referred to herein as the ramp rate, may be very fast. This fast ramp rate introduces thermal and mechanical stresses on the engine. Further, dropping quickly from-1- 4928-7931-6870.1Attny Docket No. 106389-9673full speed to a lower speed may result in the turbo causing a pressure surge in the engine. All of these factors may reduce the life of the engine.SUMMARY

[0004] One embodiment relates to a system. The system includes a controller communicably coupled to an internal combustion engine and an energy storage system, the controller including at least one processor coupled to at least one memory device storing instructions that, when executed by the at least one processor, cause the controller to perform operations including: receiving a power demand; determining a target engine speed based on the power demand; determining an engine speed ramp rate based on a power limit of the energy storage system and the target engine speed; and adjusting an engine speed of the internal combustion engine to the determined engine speed at the determined engine speed ramp rate.

[0005] In some embodiments, the instructions, when executed by the at least one processor, further cause the controller to perform operations including causing the internal combustion engine to increase to the target engine speed at the engine speed ramp rate.

[0006] In some embodiments, the instructions, when executed by the at least one processor, further cause the controller to perform operations including determining a difference in power between the power demand and an amount of electrical power generated using rotation of the engine and causing the energy storage system to output the difference in power.

[0007] In some embodiments, the instructions, when executed by the at least one processor, further cause the controller to perform operations including determining the power limit of the energy storage system based on a state of charge of an energy storage device of the energy storage system.

[0008] In some embodiments, determining the power limit of the energy storage system is based on at least one of a state of health or a temperature of the energy storage device.

[0009] In some embodiments, in response to the target engine speed being greater than a current engine speed, the engine speed ramp rate is negatively correlated with the state of -2- 4928-7931-6870.1Attny Docket No. 106389-9673charge of the energy storage device; and in response to the target engine speed being less than the current engine speed, the engine speed ramp rate is positively correlated with the state of charge of the energy storage device.

[0010] In some embodiments, the instructions, when executed by the at least one processor, further cause the controller to perform operations including receiving an indication that an operating parameter is at or above predefined threshold, the operating parameter including one of an engine speed, an engine exhaust temperature, or a peak cylinder pressure of the engine, or a turbo speed or a turbo temperature of a turbo device coupled to the engine, and, based on receiving the indication, reducing the engine speed and causing the energy storage system to output power.

[0011] In some embodiments, the power demand corresponds to an amount of electrical power demanded for performing one more functions of an electrical system.

[0012] Another embodiment relates to a system. The system includes an energy storage system electrically coupled to an electrical system; and at least one processing circuit coupled to the energy storage system, the at least one processing circuit including at least one processor coupled to at least one memory device storing instructions that, when executed by the at least one processor, cause the at least one processor to perform operations including: receiving a power demand for operating the system; determining a target engine speed for an internal combustion engine based on the power demand; determining an engine speed ramp rate based on a power limit of the energy storage system and the target engine speed for the internal combustion engine; adjusting an engine speed of the internal combustion engine based on the determined ramp rate.

[0013] In some embodiments, the instructions, when executed by the at least one processor, further cause the at least one processing circuit to perform operations including causing the internal combustion engine and the energy storage system to cooperatively output an amount of power equal to or substantially equal to the power demand to the electrical system while the engine speed increases to the target engine speed.-3- 4928-7931-6870.1Attny Docket No. 106389-9673

[0014] In some embodiments, the system is a vehicle, and the electrical system includes at least one motor configured to drive the vehicle.

[0015] In some embodiments, the power limit of the energy storage system is an output power limit, and adjusting the engine speed includes causing the engine speed to increase relative to a current engine speed.

[0016] In some embodiments, the power limit of the energy storage system is an input power limit, and adjusting the engine speed includes causing the engine speed to decrease relative to a current engine speed.

[0017] Still another embodiment relates to a method of controlling an internal combustion engine and an energy storage system. The method includes: determining, by a controller, a target engine speed of the internal combustion engine based on a power demand on the system; determining, by the controller and based on the target engine speed, a current engine speed of the internal combustion engine, and a power limit of the energy storage system, a ramp rate for changing an engine speed of the internal combustion engine from the current engine speed to the target engine speed; and increasing, by the controller, the engine speed from the current engine speed to the target engine speed at the determined ramp rate.

[0018] This summary is illustrative only and is not intended to be in any way limiting. Other aspects, inventive features, and advantages of the devices or processes described herein will become apparent in the detailed description set forth herein, taken in conjunction with the accompanying figures. 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.-4- 4928-7931-6870.1Attny Docket No. 106389-9673BRIEF DESCRIPTION OF THE FIGURES

[0019] FIG. 1 is a block diagram of a power system in a propulsion mode, according to an example embodiment.

[0020] FIG. 2 is a block diagram of the power system of FIG. 1 in a braking mode, according to an example embodiment.

[0021] FIG. 3 is a block diagram of the power system of FIG. 1 including details of a hybrid system controller and an engine, according to example embodiments.

[0022] FIG. 4 is a diagram of an algorithm executed by the power system of FIG. 3, according to example embodiments.

[0023] FIG. 5 is a block diagram of the power system of FIG. 1 including details of a hybrid system controller and an engine, according to example embodiments.

[0024] FIG. 6 is a diagram of an algorithm executed by the power system of FIG. 5, according to example embodiments.

[0025] FIG. 7 is a flow diagram of a method of operating a power system, according to an example embodiment.

[0026] FIG. 8 is a graph of various parameters of the power system of FIG. 1 during a ramp-up period and a ramp-down period, according to an example embodiment.

[0027] It will be recognized that the figures are schematic representations for purposes of illustration. The figures are provided for the purpose of illustrating one or more implementations with the explicit understanding that the figures will not be used to limit the scope of the meaning of the claims.DETAILED DESCRIPTION

[0028] Following below are more detailed descriptions of various concepts related to, and implementations of, methods, apparatuses, computer-readable media, and systems for -5- 4928-7931-6870.1Attny Docket No. 106389-9673controlling (e.g., reducing) the ramp rate of an engine of a hybrid power system using an energy storage system according to various embodiments herein. Though the examples described herein pertain primarily to the use of the hybrid power system in a vehicle, such as a hybrid mine truck, the hybrid power system may be used to provide electrical power to any electrical system from which a power demand is received. For example, the hybrid power system may provide power to vehicles, buildings, work equipment, manufacturing processes, factories, etc. or subsystems thereof (HVAC systems, infotainment systems, lighting systems, etc.). 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.

[0029] As described herein, “rotating” an engine refers to actuating one or more components of an engine system. For example, when an engine is rotated, a crankshaft, one or more camshafts, one or more timing belts, and other components may be rotated to facilitate operation of the engine. Further, when an engine 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. The rate at which the engine rotates may be measured in rotations per minute (RPM) and may be referred to herein as the “engine speed.” More specifically, rotation of the engine may be measured by an RPM of the crankshaft. As utilized herein, the term “ramp rate” as it applies to an engine means the rate of change of the engine speed. As utilized herein, the term “hybrid vehicle” refers to a vehicle that uses both an internal combustion engine and an electric motor for propulsion (at the same time and / or at different times).

[0030] As described herein, “rotating” a motor refers to the conversion of electrical power into output power (e.g., rotational output power) by the motor. For example, when an electrical current is supplied to a motor, the motor may generate a magnetic field that applies a torque to a rotor and causes the rotor to rotate. The rotor may include or be coupled to an output shaft -6- 4928-7931-6870.1Attny Docket No. 106389-9673that rotates along with the rotor and can be coupled to a mechanical component, such as a wheel or drive shaft, and may apply a torque to the mechanical component causing the mechanical component to rotate. The rate at which the motor rotates may be measured in rotations per minute (RPM) and may be referred to herein as the “motor speed.”

[0031] During normal operation of an engine, rotation of the engine is caused by the combustion of fuel within a combustion cylinder(s). More specifically, combustion of fuel within a combustion cylinder causes rotation of a crankshaft (e.g., via actuating a piston and a connecting rod). The rotation of the crankshaft 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 and / or to allow an exhaust gas stream to exit the combustion cylinder. In some embodiments, rotation of the engine is caused by an electric machine, such as a motor or motor generator. The electric machine may be coupled to the crankshaft directly or indirectly (e.g., via a clutch, a drive shaft, and / or another component). In some embodiments, the electric machine may be an electric starter, such that rotation of the engine is caused by the electric starter. For example, the electric starter may “crank” or cause rotation of the crankshaft to facilitate starting the engine.

[0032] Technically and beneficially, the embodiments described herein provide a method of controlling an internal combustion engine of a vehicle comprising an alternator, an energy storage system, and a motor. The method includes receiving a power demand, determining a target engine speed for the internal combustion engine based on the power demand, determining an engine speed ramp rate based on an output power limit of the energy storage system and the target engine speed, causing an engine speed of the engine to increase based on the determined ramp rate, and causing the engine, via the alternator, and the energy storage system (ESS) to cooperatively output an amount of power equal to the power demand to the at least one motor while the engine speed increases to the target engine speed. In vehicles (including mine trucks) in which electrical power is generated by an engine coupled to an alternator or generator and provided to a motor to, for example, drive a final drive (e.g., tracks,-7- 4928-7931-6870.1Attny Docket No. 106389-9673wheels, etc.), rapid increases in engine speed may impart stress into the engine and may reduce the lifetime of the engine. When an increase in motor speed is demanded (e.g., via user input), the engine of the vehicle may rapidly increase in engine speed so that the alternator may output sufficient power to the motor to achieve the target motor speed. In order to reduce the stress on the engine and extend the life of the engine, it may be beneficial to reduce the rate at which the engine speed changes (the “ramp rate”). In the embodiments described herein, the ESS of the vehicle may provide electrical power to the motor (in addition to the power provided by the engine via the alternator) during the period that the engine speed is “ramping up” to the target engine speed from a current (starting, original, etc.) engine speed. Thus, the engine speed ramp rate may be reduced compared to the engine speed ramp rate in a vehicle in which power is not supplied by the ESS to the motor during a ramp-up period in which the engine speed is increasing from the same starting speed to the same target speed. The ramp rate may be determined based in part on an output power limit of the energy storage system. A relatively higher output power limit from the ESS may allow for a relatively slower ramp rate, as more power may be supplied by the ESS during the ramp-up period. By reducing the ramp rate, the stress on the engine may be reduced, and the lifetime of the engine may be extended. These and other features and benefits are described more fully herein below.

[0033] Referring now to FIGS. 1 and 2, a block diagram of a power system 100 is shown respectively in a propulsion mode and a braking mode, according to an example embodiment. The power system 100 includes an engine 102 and an aftertreatment system 120 in exhaust gasreceiving communication with the engine 102. The system 100 includes a controller 140 and an operator input / output (I / O) device 130 (or user interface device), where the vehicle controller 140 is communicably coupled to the various components of FIGS. 1 and 2.

[0034] In the configuration shown in FIGS. 1 and 2, the engine 102 is an internal combustion engine (ICE). The ICE may consume fuel (e.g., gasoline, diesel fuel, hydrogen, natural gas, ethanol, etc.) to generate power and output exhaust to the aftertreatment system 120. The engine 102 may be any type of engine that generates exhaust gas, such as a gasoline, natural gas, or diesel engine, and / or any other suitable engine. In some embodiments, the engine 102-8- 4928-7931-6870.1Attny Docket No. 106389-9673may be replaced with a fuel cell (e.g., a hydrogen fuel cell). In some embodiments, the engine 102 may be a dual fuel engine that uses both diesel and natural gas.

[0035] In some embodiments, the power 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). The aftertreatment system 120 includes components used to reduce exhaust emissions, such as a selective catalytic reduction (SCR) catalyst, an oxidation catalyst (DOC), 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.

[0036] 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 power 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.

[0037] In the configuration of FIGS. 1 and 2, the power system 100 is included in a vehicle. The vehicle may be any type of on-road (e.g., highway applications) or off-road vehicle including, but not limited to, mine trucks, wheel-loaders, fork-lift trucks, line-haul trucks, midrange trucks (e.g., pick-up trucks, etc.), sedans, coupes, tanks, airplanes, boats, and any other type of vehicle. In another embodiment, the power system 100 may be embodied in a stationary piece of equipment, such as a power generator or genset. In the example shown, the vehicle is structured as a mine truck and particularly an at least partially electric mine truck (e.g., a hybrid powered mine truck). All such variations are intended to fall within the scope of the present disclosure.-9- 4928-7931-6870.1Attny Docket No. 106389-9673

[0038] The vehicle controller 140 is communicably coupled to the operator I / O device 130 and may be configured or structured to control various operations of the power system 100 (e.g., based on inputs received via the operator I / O device 130). The operator I / O device 130 enables an operator of the system 100 to communicate with the vehicle controller 140 and one or more components of the system 100 of FIG. 1. For example, the operator I / O device 130 may include, but is not limited to, an accelerator pedal or device, a brake pedal or device, an interactive display, a touchscreen device, one or more buttons and switches, voice command receivers, etc. The operator I / O device 130 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 vehicle controller 140 to connect or couple to a scan tool so that fault codes and other information regarding the vehicle may be obtained.

[0039] The vehicle 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 vehicle controller 140 is communicably coupled to the systems and components of FIG. 1, the vehicle controller 140 is structured to receive data from one or more of the components shown in FIG.1.

[0040] The vehicle controller 140 may be structured as one or more electronic control units (ECUs), such as one or more microcontrollers. The vehicle 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.

[0041] As the components of FIG. 1 are shown to be embodied in the system 100, the vehicle controller 140 may be structured as one or more electronic control units (ECU), such as a microcontroller. The vehicle controller 140 may be separate from or included with at least one -10- 4928-7931-6870.1Attny Docket No. 106389-9673of a transmission control unit, an exhaust aftertreatment control unit, a powertrain control module, an engine control module, etc.

[0042] As shown in FIGS. 1 and 2, the engine 102 is coupled to an alternator 104. For example, the crankshaft of the engine may be coupled directly or indirectly to the alternator 104. The alternator 104 converts the rotational energy produced by the engine 102 into alternating current electrical power. The alternator 104 is electrically connected to a rectifier 106, which converts the alternating current electrical power into direct current electrical power. The rectifier 106 is electrically connected to one or more power converters 108, which adjust the voltage of the direct current electrical power. The one or more power converters 108 are electrically connected to one or more inverters 110, which convert the direct current electrical power back to alternating current electrical power. The one or more inverters 110 are each electrically connected to a motor 112.

[0043] The power system may include one or more motors or electric machines (e g., a motor generator). The one or more motors 112 may be configured to drive a tractive element of the vehicle, such as a wheel or belt. The motors 112 receive the alternating current electrical power from the inverters 110 and convert the alternating current electrical power to rotational motion. For example, each motor 112 may include an output shaft coupled to a wheel of the vehicle. The inverters 110 may control the flow of power to the motors 112. The amount of power supplied to the motors 112 by the inverters 110 may control the speed and / or torque of the motor. In some embodiments, the motors 112 may include one or more electrified axles (eAxles). The vehicle controller 140 may be communicably coupled to the engine 102, the power converters 108, and the inverters 110 may each be communicably coupled to the vehicle controller 140.

[0044] As discussed above, FIG. 1 illustrates the power system 100 in propulsion mode. The arrows 114 in FIG. 1 indicate the flow of electrical power in the system 100 in propulsion mode. As an example of the operation of the power system 100 in a vehicle in propulsion mode, the vehicle controller 140 may receive an input from the operator I / O device 130 in the form of the operator pressing down on an accelerator pedal when the vehicle is stationary. In response, the vehicle controller 140 may control the engine 102 to increase the engine speed.-11- 4928-7931-6870.1Attny Docket No. 106389-9673The increase in engine speed may cause the alternator 104 to generate additional alternating current electrical power, which may then be converted to direct current electrical power by the rectifier 106. The controller may cause the power converters 108 and inverters 110 to supply the additional power from the rectifier 106 to the motors 112, which may cause the motors 112 (i.e., rotors of the motors) to rotate. As discussed above, the motors 112 may be coupled to and configured to drive one or more final drives (e.g., tracks, wheels, etc.) of a vehicle. By causing the motors 112 to rotate, the final drives may rotate to propel the vehicle from the stationary position. By increasing the power generated by the engine 102 and supplied to the motors 112, the motors 112 may turn the wheels faster, causing the vehicle to accelerate.

[0045] As shown in FIGS. 1 and 2, the power system 100 includes an energy storage system (ESS) 152. The ESS may include an energy storage device, which may be any component capable of storing electrical energy, including batteries or battery packs (e.g., lithium-ion, lead-acid, multi-chemistry), capacitors, and / or supercapacitors. The ESS 152 may be electrically coupled to the power converters 108 and the inverters 110. As shown in FIG. 1, the ESS 152 may supply power to the inverters 110 to drive the motors 112 in propulsion mode, either alone or in cooperation with the engine 102.

[0046] Referring more particularly to FIG. 2 and as shown, the ESS 152 may be configured to receive power from the inverters 110 in a braking mode. For example, when the vehicle controller 140 receives an input from the operator I / O device 130 instructing the vehicle to brake (e.g., when an operator depresses a brake pedal, when an operator downshifts in a vehicle including a multi-speed transmission, when an operator releases or partially releases an accelerator pedal, a combination of the foregoing, etc.), the vehicle controller 140 may allow the wheels to drive the motors 112 (rather than the motors driving the wheels) as the vehicle decelerates, effectively turning the motors 112 into generators. The movement of the rotor past the windings of the stator generates alternating current electrical power and a magnetic field that resists the turning of the rotor by the wheels, slowing the rotation of the wheels. This may be referred to as “regenerative braking.” The inverters 110 may act as rectifiers, converting the alternating current electrical power produced by the motors 112 to direct current electrical power. The direct current electrical power may be provided to a DC / DC converter 154, which -12- 4928-7931-6870.1Attny Docket No. 106389-9673adjusts the voltage of the direct current electrical power and supplies it to the ESS 152. In some embodiments, the ESS 152 may also receive power from the engine 102 via the alternator 104, rectifier 106, power converters 108, and DC / DC converter 154. For example, if the state of charge (“SOC”) of a battery pack of the ESS 152 is relatively low (e.g., below a predefined low SOC threshold) while the vehicle is stationary and the motors 112 are not demanding power from the engine 102, the engine 102 may be operated to generate power to recharge the battery pack.

[0047] The system 100 may include a load bank or resistor grid 158 that is electrically coupled to the power converters 108 and communicably coupled to the vehicle controller 140. When the power generated by regenerative braking is more than can be accepted by the ESS 152, the excess power may be supplied to the resistor grid 158, where it is converted to heat energy in the resistors and dissipated to the environment. For example, if the ESS 152 is a battery pack and is fully charged (e.g., a state of charge at or above a predefined full charge threshold, such as 100 percent), the power generated by the motors 112 may be routed to the resistor grid 158 rather than the ESS 152. The battery pack of the ESS 152 may also have a maximum charge rate (i.e., a maximum amount of power that can be received and stored by the battery pack). If the power produced by the motors 112 exceeds the maximum charge rate, power may be supplied to the ESS 152 at the maximum charge rate of the battery pack, and the excess power may be routed to the resistor grid 158. The vehicle controller 140 may control the flow of power from the motors 112 to the ESS 152 and resistor grid 158 based at least on the amount of power generated by the motors 112, the state of charge of the battery pack, and the state of health of the battery pack.

[0048] The engine 102 and the ESS 152 may form at least part of a hybrid system 150. In some embodiments, the hybrid system 150 may also include a hybrid system controller 156, which may be configured to determine and control how much power is supplied to the motor 112 from the engine 102 and the ESS 152 (i.e., control the power split between the engine 102 and the ESS 152). In other embodiments, the vehicle controller 140 may directly control the operation of the engine 102, the ESS 152, and other components of the hybrid system 150. In some embodiments, the hybrid system controller 156 may be a component of the vehicle -13- 4928-7931-6870.1Attny Docket No. 106389-9673controller. The hybrid system controller 156 may be structured as one or more electronic control units (ECUs), such as a microcontroller. The function and structure of the hybrid system controller 156 are described in greater detail in FIGS. 3 and 4. The hybrid system controller 156 may be separate from or included with the vehicle controller 140.

[0049] The system 100 includes at least one blower 160 in fluid communication with at least one of the motors 112 and configured to cause cooling air to flow over the at least one of the motors 112, the alternator 104, the resistor grid 158, the vehicle controller 140, and any other components of the system 100. Though several blowers 160 are each shown in FIGS. 1 and 2 in fluid communication with one component, it should be understood that one blower 160 may be in fluid communication with and configured to cause cooling air to flow over multiple components. The hybrid system 150 further includes a cooling system 162 (e.g., an air cooling system, a liquid cooling system, etc.) in thermal communication with and configured to cool the ESS 152 and the DC / DC converter 154.

[0050] Now referring to FIG. 3, a schematic diagram of the system 100 of FIG. 1, illustrating the hybrid system controller 156 and the engine 102 in further detail, is shown, according to an example embodiment. As shown, the hybrid system controller 156 includes at least one processing circuit 202 having at least one processor 204 and at least one memory device 206, an ESS power limit circuit 210, an engine ramp rate circuit 212, a power demand bias circuit 214, and a communications interface 216. The hybrid system controller 156 is configured to determine and control how much power is supplied to the motor 112 from the engine 102 and the ESS 152 (i.e., control the power split between the engine 102 and the ESS 152). In some embodiments, the vehicle controller 140 may include the hybrid system controller 156 or may otherwise be configured to perform the functions of the hybrid system controller 156 described herein. Specific processes for controlling the operation of the power system 100 including the hybrid system 150 are described herein below.

[0051] In one configuration, the ESS power limit circuit 210, the engine ramp rate circuit 212, and / or the power demand bias circuit 214 are 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 facilitate performance of -14- 4928-7931-6870.1Attny Docket No. 106389-9673certain 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.).[0052J In another configuration, the ESS power limit circuit 210, the engine ramp rate circuit 212, and / or the power demand bias circuit 214 are embodied as one or more hardware units, such as one or more electronic control units. As such, the ESS power limit circuit 210, the engine ramp rate circuit 212, and / or the power demand bias circuit 214 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 ESS power limit circuit 210, the engine ramp rate circuit 212, and / or the power demand bias circuit 214 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 ESS power limit circuit 210, the engine ramp rate circuit 212, and / or the power demand bias circuit 214 may include any type of component for accomplishing or facilitating the 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 ESS power limit circuit 210, the engine ramp rate circuit 212, and / or the power demand bias circuit 214 may also include or be programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like. The ESS power limit circuit 210, the engine ramp rate circuit 212, and / or the power demand bias circuit 214 may include one or more memory -15- 4928-7931-6870.1Attny Docket No. 106389-9673devices for storing instructions that are executable by the processor(s) of ESS power limit circuit 210, the engine ramp rate circuit 212, and / or the power demand bias circuit 214. 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 ESS power limit circuit 210, the engine ramp rate circuit 212, and / or the power demand bias circuit 214 may be geographically dispersed throughout separate locations in the vehicle. Alternatively, and as shown, the ESS power limit circuit 210, the engine ramp rate circuit 212, and / or the power demand bias circuit 214 may be embodied in or within a single unit / housing, which is shown as the hybrid system controller 156.

[0053] In the example shown, the hybrid system controller 156 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 ESS power limit circuit 210, the engine ramp rate circuit 212, and / or the power demand bias circuit 214. The depicted configuration represents the ESS power limit circuit 210, the engine ramp rate circuit 212, and / or the power demand bias circuit 214 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 ESS power limit circuit 210, the engine ramp rate circuit 212, or the power demand bias circuit 214 is configured as a hardware unit. All such combinations and variations are intended to fall within the scope of the present disclosure.

[0054] 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 -16- 4928-7931-6870.1Attny Docket No. 106389-9673with 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 ESS power limit circuit 210, the engine ramp rate circuit 212, or the power demand bias circuit 214 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 multithreaded instruction execution. All such variations are intended to fall within the scope of the present disclosure.[0055J 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.

[0056] 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.-17- 4928-7931-6870.1Attny Docket No. 106389-9673The 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).

[0057] As shown in FIG. 3, the communications interface 216 may enable communication with the engine 102 (and / or a component thereof), the ESS 152 (and / or a component thereof), one or more turbo devices 122, and / or the vehicle controller 140. In some embodiments, the communications interface 216 may enable communication with the air supply 115. In some embodiments, the communications interface 216 may enable communication with the motors 112 and / or the inverters 110.

[0058] The engine 102 may include or be associated with an engine controller 218, which may include at least one processing circuit 220 having at least one processor 222 and at least one memory device 224, and a communications interface 226, which may respectively be structurally and functionally similar to the at least one processing circuit 202, the at least one processor 204, the at least one memory device 206, and the communications interface 216. The engine controller 218 may further include a fueling and air handling circuit 228 configured to control components of the engine 102 and other components of the power system to control the delivery of air and fuel to the cylinders of the engine 102. For example, based on the target engine speed and ramp rate determined by the engine ramp rate circuit 212 and received from the hybrid system controller 156, the fueling and air handling circuit 228 may control a fuel system 124 and an air supply 115 to supply fuel and / or air to the cylinders of the engine 102 such that the engine 102 ramps up to the target engine speed at the determined ramp rate. The engine controller 218 may control the amount, timing, pressures, and blend ratios of fuel and air supplied to the cylinders of the engine 102 by the fuel system 124 and the air supply 115 based on the determined target engine speed and ramp rate. In embodiments in which the engine 102 is a spark ignition engine, the engine controller 218 may also control the spark timing of spark plugs based on the ramp rate and target engine speed. In embodiments in which the engine is a variable valve actuation engine, the phaser angles could be adjusted and / or certain cylinder firing cycles could be skipped to adjust the power output of the engine 102. Single or two-stage turbos, eTurbos, eCompressors, and / or eWastegates could be adjusted -18- 4928-7931-6870.1Attny Docket No. 106389-9673to control the flow of air to the cylinders to adjust the power output of the engine 102. The aftertreatment system 120 may also be adjusted based on the adjusted engine ramp rate to ensure that the vehicle meets emissions standards. For example, during a ramp-down period in which the engine 102 is providing more power than in a typical system, controls and dosing timing, amounts, and temperatures could be adjusted to account for the additional fuel being burned. Thus, as described above, rather than simply changing the engine operating point, the target engine speed and calculated ramp rate are used to adjust the air-handling, fuel blending, fuel injection strategy, hybrid systems, braking systems (e.g., during a ramp-down period), and the aftertreatment system to optimize operation of the vehicle and prolong the life of the engine.

[0059] As shown in FIG. 3, the power system 100 includes an air supply 115 structured to provide an air stream to the engine 102. The air supply 115 may be controlled by the engine controller 218 or the hybrid system controller 156, such that the controllers 218 and / or 156 are operative to adjust an amount of air provided to the cylinders of the engine 102 by the air supply 115. In some embodiments, the air supply 115 is or includes a compressed air supply (e.g., a compressed air storage tank). In other embodiments, the air supply 115 is a supercharger or other device configured to provide compressed air to the engine 102. In some embodiments, the air supply 115 is belt-driven, chain-driven, gear-driven, or electric-driven. In some embodiments, the air supply 115 includes the turbo device 122.

[0060] The power system 100 also includes a fuel system 124. The fuel system 124 is configured to provide fuel (e.g., hydrogen) to the engine 102. More specifically, the fuel system 124 is configured to provide fuel to each of the cylinders of the engine 102. The fuel system 124 may include one or more components for providing the fuel to the engine 102, such as a storage tank for storing the fuel, and / or one or more regulators (e.g., valves, solenoids, etc.) for controlling an amount or a timing of fuel provided to the engine 102.

[0061] In some embodiments, the engine controller 218 or the hybrid system controller 156 is operatively coupled to the fuel system 124 such that the controller 218 and / or 156 may control the operation of the fuel system 124. More specifically, the controller 218 and / or 156 may-19- 4928-7931-6870.1Attny Docket No. 106389-9673control the fuel system 124 to control an amount and / or a timing of fuel provided to the engine 102.

[0062] The hybrid system controller 156 is configured to determine how much of the power delivered to the motors 112 is delivered from the engine 102 or from the ESS 152. For example, in some circumstances, the motor(s) 112 may be driven only using power from the ESS 152, and in other circumstances, the motor(s) 112 may be driven only using power from the engine 102. In some circumstances, the motor(s) 112 may be driven in part by power from the engine 102 and in part by power from the ESS 152. For example, as discussed above, the hybrid system 150 may be part of a mine truck subject to frequent changes in load, and the hybrid system controller 156 may be configured to determine an engine speed ramp rate of the engine 102. For example, the hybrid system controller 156 may be configured to reduce (e.g., relative to a system in which the engine 102 alone is used to power the motors) the ramp rate of the engine 102 by supplying some of the power from the ESS 152 to the motors 112 while the engine speed of the engine ramps up. FIG. 4 shows an algorithm 400 for determining a ramp rate for the engine 102 according to an example embodiment, which may be executed or performed by the power system of FIG. 3.

[0063] The ESS power limit circuit 210 is configured to determine a power limit of the ESS 152. As used herein, the “power limit” of the ESS 152 refers to the maximum amount of power that can be output by the ESS 152 or input into the ESS 152. Thus, respectively, the “power limits” may be referred to as the “output power limit” and the “input power limit” for the ESS 152. In some embodiments, the input power limit and the output power limit may be the same, while in other embodiments, the input power limit and the output power limit may be different. As discussed above, the ESS 152 may include one or more battery packs and / or supercapacitors. In embodiments in which the ESS 152 includes a battery pack and / or a supercapacitor, the power limit may depend on the original storage and power delivery capacities of the battery pack and / or supercapacitor, the state of charge of the battery pack or supercapacitor, the state of health of the battery pack or supercapacitor, and the temperature of the battery pack or supercapacitor. As used herein, the “state of health” of a battery pack and / or supercapacitor refers to the current storage capacity of the battery pack or supercapacitor -20- 4928-7931-6870.1Attny Docket No. 106389-9673relative to the original storage capacity of the battery pack or supercapacitor. For example, a battery pack that had an original storage capacity of 100 amp-hours and that currently has a storage capacity of only 85 amp-hours may be understood to have a state of health of 85 percent. As used herein, the “state of charge” of a battery pack or supercapacitor refers to the current level of stored charge or the current level of stored charge relative to the current storage capacity of the battery pack or supercapacitor. For example, a battery pack with a current level of charge of 76.5 amp-hours and a current storage capacity of 85 amp-hours may be understood to have a state of charge of 90 percent or 76.5 amp-hours. The hybrid system controller 156 may receive, via the communications interface 216, the state of charge, state of health, and temperature of the battery pack from the ESS 152.

[0064] The one or more memory devices 206 may store information regarding the battery packs of the ESS 152. For example, the one or more memory devices 206 may store the original storage and power delivery capacities of the battery pack. In some embodiments, the state of health of the battery pack may be determined or estimated as a function of the lifetime charging and discharging times of the battery. For example, the one or more memory devices 206 may store a formula or a look-up table for calculating or determining the state of health of the battery pack. The hybrid system controller 156 may receive the lifetime charging and discharging times of the battery from the ESS 152, and the ESS power limit circuit 210 may determine the state of health of the battery.

[0065] As discussed above, the ESS power limit circuit 210 is configured or structured to determine a power limit of the ESS 152 based on at least the state of charge of the battery pack, the state of health of the battery pack, and / or the temperature of the battery pack. As shown in FIG. 4, the ESS power limit circuit 210 receives the state of charge of the battery pack, the state of health of the battery pack, and / or the temperature of the battery pack. The power limit of a battery pack may decrease with a decreasing state of charge and / or a decreasing state of health and may increase with an increasing temperature to within an upper limit at which the battery pack can operate as desired. The one or more memory devices 206 may store a formula or a look-up table for calculating or determining the power limit of the ESS 152.-21- 4928-7931-6870.1Attny Docket No. 106389-9673

[0066] The engine ramp rate circuit 212 is configured to determine the ramp rate for the engine 102. The hybrid system controller 156 may receive, via the communications interface 216, a power demand or a regeneration demand from the vehicle controller 140. “Power demand,” as used herein, refers to an amount of power (e.g., mechanical power, electrical power, a combination thereof) demanded by the vehicle controller 140 to be supplied to components of the vehicle, including the motors 112, as well as any other auxiliary electrical components of the vehicle powered by the hybrid system 150 (e.g., the blowers 160, the cooling system 162, headlights, power steering, etc.). In some embodiments, the systems described herein may be applied to electrical systems or devices other than vehicles. For example, electrical power may be provided from the ESS 152 and the engine 102 (via the alternator 104) to any electrical system (e g., a building, work equipment, a manufacturing process, etc.) that generates a power demand for performing one or more operations. It should be understood that, in some embodiments, some of the auxiliary components may be powered by a separate battery pack or system from the hybrid system 150. “Regeneration demand,” as used herein, refers to the amount of power generated through regenerative braking by the motors 112 that needs to be absorbed by the ESS 152 or discharged via the resistor grid 158. As shown in FIG. 4, the engine ramp rate circuit 212 may also receive the power limit of the ESS 152 from the ESS power limit circuit 210. The engine ramp rate circuit 212 may determine the ramp rate of the engine 102 based on at least the power demand and the power limit of the ESS 152.

[0067] It should be understood that the system 100 shown in FIGS. 1 and 2 relates to an example embodiment in which mechanical power generated by the engine 102 is converted into electrical power by the alternator 104 before being used to drive the final drive (e.g., wheels) using the motors 112. In other embodiments, the system may be configured to supply power (i.e., torque) directly from the engine 102 to components of the system 100. For example, the engine 102 may be configured to directly turn (e.g., via a transmission, via a driveshaft, etc.) the wheels of a vehicle without the use of an alternator 104 and a motor 112. In a hybrid system, a motor 112 may be used in conjunction with the engine to drive the vehicle. For example, the wheels of a first axle of the vehicle may be powered directly by the engine 102 without a motor 112, and the wheels of a second axle of the vehicle may be powered by a motor 112 (e.g., an eAxle). Upon receiving a power demand, the hybrid system controller 156-22- 4928-7931-6870.1Attny Docket No. 106389-9673may determine a ramp rate and control how much power is provided by the engine 102 to the wheels of the first axle (e.g., by controlling the engine speed, engine fueling, etc.) and how much power is provided by the motor 112 to the wheels of the second axle (e.g., by controlling the flow of electrical power from the ESS 152 to the motor 112). In other embodiments, an engine 102 and a motor 112 may both be coupled to a common driveshaft. Based on the determined ramp rate, the hybrid system controller 156 may control how much torque is provided to the driveshaft by each of the engine 102 and the motor 112. Thus, the power demand may correspond to or include an amount of mechanical power demanded to drive the wheels or other mechanical components of a system and is not limited to a demand for electrical power.[0068J Propulsion mode may refer to circumstances in which the hybrid system 150 is providing power to the motors 112 and / or other components of the vehicle. For example, propulsion mode may include supplying power to the motors 112 to propel a mine truck and / or may include supplying power to a hydraulic system to lift the bed of the mine truck (among potential other power exerting operations). In the propulsion mode, where the vehicle controller 140 is demanding that the hybrid system 150 provide more power to drive the motors 112 faster, the engine ramp rate circuit 212 determines a ramp rate for the engine 102 based on the power demand and the output power limit of the ESS 152. The ramp rate of the engine 102 in the hybrid system 150 may be lower than a ramp rate of an engine in a system without an ESS. The engine ramp rate circuit 212 may determine, based on the power demand from the vehicle controller 140, a target engine speed. In a system without an ESS, a controller of the engine may operate the engine to ramp up to the target engine speed as fast as possible. For example, the engine may ramp up from a first speed (e.g., 800 RPM) to a second higher speed (e.g., 1800 RPM) over the course of a predefined operating duration (e.g., ten seconds). This increase in engine speed may impart stress into the engine and may reduce the lifetime of the engine. In the hybrid system, the ESS 152 may provide a portion of the power that would otherwise be generated by the engine 102, allowing the engine to be ramped up at a lower ramp rate. For example, the engine may ramp up from the first speed of 800 RPM to the second speed of 1800 RPM over the course of an extended operating period, such as 20 seconds, while the ESS 152 provides some of the power to meet the power demand.-23- 4928-7931-6870.1Attny Docket No. 106389-9673

[0069] When the target engine speed is set at a higher engine speed, the ESS 152 may initially provide all or nearly (e.g., 100 percent) of the increase in output power, or if the power demand is greater than the output power limit of the ESS 152, the ESS 152 may output power at its output power limit. As the engine 102 ramps up to the target engine speed and begins to produce more electrical power (e.g., via the alternator 104), the power supplied by the ESS 152 gradually decreases until the engine 102 reaches the target engine speed. If the engine 102 produces enough power at the target engine speed to meet the power demand, no power (or power amounts below a predefined threshold) may be supplied by the ESS when the engine 102 reaches the target engine speed. If the power demand exceeds the power generated at the target engine speed (e.g., if the power demand is higher than the power produced by the engine 102 at the maximum engine speed), the ESS 152 may continue to supply power even after the engine 102 reaches the target engine speed.

[0070] As discussed above, the engine ramp rate circuit 212 may be configured to determine the ramp rate of the engine 102 based on at least the power demand from the vehicle controller 140 and the power limit of the ESS 152, and the power limit of the ESS 152 may be based in part on the state of charge of a battery pack. Thus, the ramp rate of the engine 102 may depend on the state of charge of the battery pack. For example, if the state of charge is at a minimum state of charge below which the battery pack cannot supply power (or cannot supply power at desired rates), the ramp rate may be the same as it would be if no ESS 152 were present. If the battery pack is at a state of charge that is above the minimum state of charge, but low enough that it would reach the minimum state of charge if the engine 102 were to take more than a predefined amount of time (e.g., 15 seconds) to reach the target engine speed, engine ramp rate circuit 212 may determine a ramp rate that ensures or attempts to ensure that the engine 102 takes no more than the predefined amount of time (e.g., 15 seconds) to reach the target engine speed. In some embodiments, the ramp rate may be roughly constant until the engine 102 reaches the target engine speed. In other embodiments, the ramp rate may vary as the engine speed increases to the target engine speed. For example, experimental data (e.g., simulations) may indicate that the most stress on the engine occurs when the engine speed is beginning to ramp up. If the state of charge of the battery pack is not sufficient to provide power throughout the entire ramp-up period, the ESS 152 may provide power only during the beginning of the -24- 4928-7931-6870.1Attny Docket No. 106389-9673ramp-up period. In some embodiments, the state of charge of the ESS 152 may be used to determine a constant ramp rate. For example, if the state of charge is relatively low, the ramp rate may be relatively fast, while if the state of charge is relatively high, the ramp rate may be slower.

[0071] In some embodiments, the hybrid system controller 156 may be configured to delay ramping of the engine 102 based on the output power limit of the ESS 152. For example, if the power demand from the vehicle controller 140 (or the increase in power demand) is less than the output power limit of the ESS 152, the ESS 152 may provide all of the power or the increase in power, and the engine speed of the engine 102 may not be changed. If the output power limit of the ESS 152 drops (e.g., as the state of charge of a battery pack decreases) to near or below the power demand, the engine ramp rate circuit 212 may determine a ramp rate for the engine 102, and the engine speed may be increased so that the engine 102 can supply more power as the power supplied by the ESS 152 decreases. In some embodiments, the engine ramp rate circuit 212 may monitor the power demand to determine a running average or a moving average window of the power demand. If, for example, a moving average window of the power demand indicates that the output power limit of the ESS 152 will or likely will be sufficient to meet the power demand, the engine speed of the engine 102 may not be increased. If, however, the moving average window of the power demand indicates a likelihood of sustained elevated power demand, the engine ramp rate circuit 212 may determine a target engine speed and ramp rate for the engine 102. Thus, for example, if a mine truck is making infrequent, short movements, the engine ramp rate circuit 212 may determine that increasing the engine speed of the engine 102 is not needed and the ESS 152 can provide the demanded power, but if the mine truck is driving steadily uphill, the engine ramp rate circuit 212 may determine a target engine speed and ramp rate for the engine 102. This may help ensure, for example, that a battery pack of the ESS 152 does not fall to the minimum state of charge.

[0072] As discussed above, the braking mode may include using the motors 112 as generators to actively brake the vehicle and regenerate electrical power. Braking mode may be engaged when, for example, an operator depresses a brake pedal, an operator downshifts in a vehicle including a multi-speed transmission, an operator releases or partially releases an accelerator -25- 4928-7931-6870.1Attny Docket No. 106389-9673pedal, a combination of the foregoing, etc. Braking mode may also include the engine speed of the engine 102 decreasing as the power demand drops, whether or not the motors 112 are regeneratively braking the vehicle. For example, a mine truck may be in propulsion mode when the hydraulic system requires power to lift the truck bed but may enter braking mode when the truck bed reaches its set point or is lowered as the power demand (and thus, the target engine speed) decreases. Accordingly, it should be understood that braking mode does not necessarily require slowing or braking of the vehicle.

[0073] In the braking mode, when the power demand from the vehicle controller 140 decreases, the engine ramp rate circuit 212 may determine a ramp rate for the engine 102 based on the power demand and the input power limit of the ESS 152. The ramp rate of the engine 102 in the hybrid system 150 may be lower than a ramp rate of an engine in a system without an ESS. The engine ramp rate circuit 212 may determine, based on the power demand from the vehicle controller 140, a target engine speed. In a system without an ESS, a controller (e.g., vehicle controller 140) may operate the engine to ramp down to the target engine speed as fast as possible. For example, the engine may ramp down from a second elevated speed (e.g., 1800 RPM) to a first lower speed (e.g., 800 RPM) in less than a predefined short operating time period (e.g., less than five seconds). The sudden drop in power demand may also cause the engine 102 to overspeed and / or the turbo device 122 to surge, which may cause damage and / or a reduction in lifetime of the engine 102 and / or the turbo device 122. For example, a sudden drop in power demand and engine speed may reduce the amount of air supplied to the engine 102, causing the air pressurized by the turbo device 122 to build in pressure and slow, stop, or reverse the rotation of the blades of the turbo device 122, which may be harmful to the turbo device 122. As another example, if the motors 112 are used for regenerative braking, the power generated may be supplied to the resistor grid 158. However, if the power generated exceeds the capacity of the resistor grid 158, the excess power may be provided to the alternator 104.

[0074] Engines, such as mine truck engines, may run at rated speed and rated power in order to satisfy the power demand from the vehicle. When there is a sudden drop in power demand, there may be situations where the engine over-speeds and this has an impact on the overall life -26- 4928-7931-6870.1Attny Docket No. 106389-9673of the engine especially with frequent cyclical occurrences. The turbos may experience similar stress during overspeed situations. Exhaust and turbo system failures contribute to a significant portion of the repairs needed in the field. In the hybrid system, when there is a sudden drop in power demand (a drop in power demand by more than a predefined amount in a predefined period of operation, such as less than ten seconds), the hybrid system controller 156 and / or the vehicle controller 140 may be configured to deliver at least some of the excess power generated by the engine 102 during the ramp-down to the ESS 152. By doing so, the ramp rate may be lowered to reduce the possibility of engine overspeed or turbo surge. For example, when a mine truck transitions from an uphill, drive to a stop, the power demand from the mine truck may suddenly drop. Rather than ramping down the engine speed in less than the predefined amount of time (e.g., one second), the engine ramp rate circuit 212 may determine a ramp rate allowing the engine to ramp down over a relatively greater amount of time (e.g., fifteen seconds). During that relatively greater amount of time, the power generated by the engine 102, which is not needed by the motors 112 of the stopped mine truck, can be delivered to the ESS 152, for example, to charge the battery pack. If the amount of power generated by the engine 102 during the ramp-down period exceeds the input power limit of the ESS 152, the excess power may be delivered to the resistor grid 158. When the state of charge of the ESS (e.g., a battery pack of the ESS 152) is near a maximum state of charge, the system 100 may be configured to increase the power use from the ESS 152 (relative to the engine 102) to ensure that the ESS 152 has sufficient capacity to absorb power the next time the power demand decreases.

[0075] When the target engine speed is set at a higher engine speed than a current engine speed, the ESS 152 may initially provide all or nearly all (e.g., 100 percent) of the increase in output power, or if the power demand is greater than the output power limit of the ESS 152, the ESS 152 may output power at its output power limit. As the engine 102 ramps up to the target engine speed and begins to produce more electrical power (e.g., via the alternator 104), the power supplied by the ESS 152 gradually decreases until the engine 102 reaches the target engine speed. If the engine 102 produces enough power at the target engine speed to meet the power demand, no power, or power amounts below a low threshold amount, may be supplied by the ESS when the engine 102 reaches the target engine speed. If the power demand exceeds -27- 4928-7931-6870.1Attny Docket No. 106389-9673the power generated at the target engine speed (e.g., if the power demand is higher than the power produced by the engine 102 at the maximum engine speed), the ESS 152 may continue to supply power even after the engine 102 reaches the target engine speed. If power is also generated by the motors 112 by regenerative braking, the power can also be delivered to the ESS 152 and / or the resistor grid 158.

[0076] As in the propulsion mode, the engine ramp rate circuit 212 may determine the ramp rate based on the power limit of the ESS 152 (in this case, the input power limit) and the power demand received from the vehicle controller 140. In the case that the ESS includes a battery pack, the input power limit may be based on the state of charge, state of health, and temperature of the battery pack. For example, if the battery pack of the ESS 152 is at a maximum state of charge, the engine ramp rate circuit 212 may determine that a very fast ramp rate may be required to slow the engine 102 before more power is generated than can be absorbed by the resistor grid 158. If the battery pack of the ESS 152 is not near the maximum state of charge, the engine ramp rate circuit 212 may determine a relatively slow ramp rate to protect the engine 102 and turbo device(s) 122 from damage. If the battery pack of the ESS 152 is near (but not at) the maximum state of charge, the engine ramp rate circuit 212 may determine an intermediate ramp rate between the very fast ramp rate (when the battery pack is at the maximum state of charge) and the relatively slow ramp rate (when the battery pack is not near the maximum state of charge). If the battery pack of the ESS 152 is near the minimum operational state of charge, the ramp rate may be even lower so that additional power can be provided to the ESS 152 for use during the next time the power demand increases. As shown in FIG. 4, based on the determined ramp rate, the engine ramp rate circuit 212 may output an adjusted engine power demand to the fueling and air handling circuit 228 of the engine controller 218. The “adjusted engine power demand” refers to the power that is demanded from the engine 102, for example, after subtracting the power to be supplied by the ESS 152 from the total power demand. Based on the adjusted engine power demand, the fueling and air handling circuit 228 determines a fueling command, a torque command, and an engine speed target for the engine 102, which the engine controller 218 may use to control the speed of the engine 102.-28- 4928-7931-6870.1Attny Docket No. 106389-9673

[0077] The power demand bias circuit 214 is configured or structured to determine whether to bias the hybrid system 150 towards more power being supplied by the ESS 152 or more power supplied by the engine 102 (i.e., control the power split between the engine 102 and the ESS 152). In some embodiments, the hybrid system 150 may be biased towards more power being supplied by the ESS 152 when an operating parameter of the engine 102 and / or the turbo device 122 is near an operating limit or threshold. For example, as shown in FIG. 4, the hybrid system controller 156 may receive, via the communications interface 216, an engine speed, an engine exhaust temperature, and / or a peak cylinder pressure from the engine controller 218 (or one or more sensors coupled to or associated with the engine 102) and a turbo speed and / or a turbo temperature from the one or more turbo devices 122 (or one or more sensors coupled to or associated with the turbo devices 122). If any of these values approach a corresponding threshold limit, the power demand bias circuit 214 may determine to bias the hybrid system 150 towards more power being supplied by the ESS 152 so that the engine speed can be reduced. The power demand bias circuit 214 may send the determined power demand bias to the engine ramp rate circuit 212, and the calculation of the ramp rate by the engine ramp rate circuit 212 may be further based on the power demand bias. In addition to moving the engine 102 and the turbo devices 122 away from their operating limits when power demand is high, this may also help to allow for a lower ramp rate when the power demand drops, as the overall change in engine speed when the power demand drops may be lower. Further, discharging power from the ESS (e.g., from a battery pack) helps to open up storage capacity in the ESS 152 for the next time the power demand drops, so that engine 102 can be slowed at a slower ramp rate while the ESS 152 absorbs the excess power.

[0078] Data may be exchanged between the engine ramp rate circuit 212 and the power demand bias circuit 214 to determine the ramp rate and control the power split between the ESS 152 and the engine 102. For example, the power demand bias circuit 214 may receive a ramp rate from the ramp rate circuit 212 and determine how much power should be supplied by the ESS 152 and how much power should be supplied by the engine 102. Upon determining, for example, that the engine 102 or the ESS 152 will need to reach or exceed an operating limit to supply the determined power, the power demand bias circuit 214 may determine that the target ramp rate cannot be achieved or that achieving the target ramp rate may cause additional stress -29- 4928-7931-6870.1Attny Docket No. 106389-9673on the engine 102 (e.g., a stress amount beyond a predefined threshold tolerable amount). The power demand bias circuit 214 may then request an updated ramp rate from the engine ramp rate circuit 212 that can be achieved without reaching or exceeding the operating limit.

[0079] If each of these values is not close to its corresponding threshold limit (e.g., within a predefined tolerance of the limit, whereby the tolerance may differ for each parameter relative to its threshold limit), the power demand bias circuit 214 may not bias the hybrid system 150 towards more power being supplied by the ESS 152 to the motors 112. For example, if each of these values is not close to its corresponding threshold limit, no power, or power amounts below a predefined threshold amount, may be supplied by the ESS 152 to the motors 112 once the engine reaches the target engine speed.

[0080] Referring now to FIG. 5, a schematic diagram of the system 100 of FIG. 1, illustrating the hybrid system controller 156 and the engine 102 in further detail, is shown, according to another example embodiment. The system 100 of FIG. 5 may be substantially similar to the system of FIG. 3, except that the engine controller 218 includes the engine ramp rate circuit 212 rather than the hybrid system controller 156. Thus, the engine controller 218 may receive the power demand, the power limit of the ESS 152, and the power demand bias from the hybrid system controller 156 via the communications interfaces 216, 226. The engine controller 218 may then determine the ramp rate for the engine 102 based on the power demand and control the engine 102 to increase or decrease speed according to the determined ramp rate and target speed. FIG. 6 shows an algorithm 500 for determining a ramp rate for the engine 102 according to an example embodiment, which may be executed or performed by the power system of FIG. 5. Thus, algorithm 500 of FIG. 6 may be substantially similar to the algorithm 400 of FIG. 4 except that the engine controller 218, rather than the hybrid controller, determines the ramp rate. It should be understood that the embodiments of FIG. 3 and 5 are examples, and that various processing and control functions may be performed by at least one processor coupled to at least one memory device in the system 100.

[0081] Based on the foregoing, referring now to FIG. 7, a flow diagram of a method 300 of controlling the operation of an engine and an ESS in a hybrid system, such as the hybrid system 150, is shown, according to an example embodiment. The hybrid system may be embodied -30- 4928-7931-6870.1Attny Docket No. 106389-9673within a vehicle, such as a mine truck. The operations of the method 300 may be performed, for example, by one or more processors based on instructions stored in one or more memory devices of one or more controllers. For example, the method 300 may be performed by at least one of the vehicle controller 140, the hybrid system controller 156, and / or the engine controller 218.

[0082] At operation 302 of the method 300, a power demand is received for operating the system (e.g., the vehicle), a subsystem thereon (e.g., a motor), or any other electrical system (e.g., an electrical system of a building or manufacturing process, etc.). For example, the vehicle controller 140 may receive a power demand from a user via the operator I / O device 130. The operator VO device 130 may be, for example, an accelerator pedal of a mine truck. In some embodiments, the hybrid system controller 156 may receive the power demand from the vehicle controller 140.

[0083] At operation 304 of the method 300, at least one engine or turbo parameter is received. The at least one engine and turbo parameters may include, for example, an engine speed, a peak cylinder pressure of the engine (or another measurement corresponding to or indicating the peak cylinder pressure), an exhaust temperature of the engine, a speed of the turbo, and / or a temperature of the turbo (among other engine and / or turbo parameters). The engine and / or turbo parameters may be received by the hybrid system controller 156.

[0084] At operation 306 of the method 300, a power demand bias is determined based on the engine and turbo parameters. The power demand bias may indicate a preference for reducing the engine speed and supplying power from the ESS if one or more of the engine and / or turbo parameters are near a predefined limit threshold. For example, operating the engine 102 near its limit threshold of peak cylinder pressure may cause damage and / or wear on the engine 102. If the engine 102 is operating near this limit threshold, the power demand bias may include a request or preference for the engine speed to be reduced and power (or more power) to be supplied by the ESS.

[0085] At operation 308 of the method 300, ESS parameters are received from the ESS. The ESS parameters may include, for example, a state of charge, a state of health, and / or a -31- 4928-7931-6870.1Attny Docket No. 106389-9673temperature of an energy storage device within the ESS (e.g., a battery pack, a supercapacitor, etc.) (among others). The ESS parameters may be received, for example, by the hybrid system controller 156 from the ESS 152. At operation 310 of the method 300, an ESS power limit is determined based on the ESS parameters. As discussed above, the ESS power limit may refer to the amount of power that the ESS can receive (e.g., an input power limit) or supply (e.g., an output power limit), which may vary based on the state of charge, the state of health, and / or the temperature of the energy storage device of the ESS.

[0086] At operation 312 of the method 300, a target engine speed is determined and / or received. In some embodiments, the target engine speed may be determined based on the power demand. For example, in some embodiments, the engine, via the alternator, may generate all of the electrical power demanded by the system once the ramp-up period is complete. Thus, the ESS may provide power during the ramp-up period, but at the target engine speed, the engine provides all of the electrical power demanded and the ESS does not provide any power. The power output by the alternator may be correlated to engine speed. For example, an increase in engine speed may cause an increase in power output according to a known output curve (e.g., determined by experimentation). When a power demand is received, the engine speed may be determined using the output curve such that the power output by the engine matches the power demand.

[0087] In some embodiments, the target engine speed may be determined (e.g., by the hybrid system controller 156) based on the power demand, the power demand bias, the ESS parameters, and the ESS power limit. For example, if none of the engine or turbo parameters is near the threshold limits, the power demand bias may not include a request or preference for a lower engine speed. However, if the power demand bias does include a request or preference for a lower engine speed because one of the engine or turbo parameters is near the respective threshold limit, the hybrid system controller 156 may take into account the ESS parameters in determining the target engine speed. If, for example, the state of charge of the energy storage device of the ESS 152 is below a certain threshold, the target engine speed may be determined based on the engine 102 alone providing the power to meet the power demand. If instead, the state of charge of the ESS 152 is sufficient to provide some of the power to meet the power -32- 4928-7931-6870.1Attny Docket No. 106389-9673demand, the hybrid system controller 156 may determine a target engine speed that is lower than it would be if the engine 102 alone provided the power to meet the power demand, for example, if the lower engine speed results in more efficient operation of the engine 102. Similarly, the target engine speed may be determined to maximize efficiency of the engine 102 even if the engine 102 operating at the target engine speed produces more power than demanded. Excess power may be used to charge the energy storage device of the ESS 152 while the operating efficiency of the engine 102 is improved to a desired operating character! stic(s). In some embodiments, even if the current engine and turbo parameters are not near their threshold limits, if the hybrid system controller 156 determines that the target engine speed is likely to move the engine and turbo parameters to near their threshold limits, the hybrid system controller 156 may adjust the target engine speed downward if the ESS parameters allow for power to be supplied by the ESS 152. The ESS 152 may supply power up to the ESS power limit, and the target engine speed may be determined based on how much the power demand exceeds the ESS power limit.

[0088] At operation 314 of the method 300, an engine speed ramp rate for the engine is determined. The ramp rate may be determined (e.g., by the hybrid system controller 156) based on the current engine speed, the target engine speed, the power demand bias, the ESS parameters, and the ESS power limit. For example, the greater the change in engine speed from a first engine speed to a second engine speed, the greater (i.e., faster) the ramp rate may be. If the ESS power limit and / or the state of charge of the ESS is relatively low, a faster ramp rate may be determined when the target engine speed is faster than the current engine speed, or a slower ramp rate may be determined when the target engine speed is slower than the current engine speed. Thus, when the target engine speed is faster than the current engine speed, the engine speed ramp rate may be negatively correlated with the state of charge of the energy storage device, and when the target engine speed is slower than the current engine speed, the engine speed ramp rate may be positively correlated with the state of charge of the energy storage device.

[0089] For example, if the ESS power limit is below a first threshold, and the target engine speed is above the current engine speed, the ramp rate may be greater (i.e., faster) than the ramp -33- 4928-7931-6870.1Attny Docket No. 106389-9673rate for the same current engine speed and target engine speed when the ESS power limit is above the first threshold. Similarly, if the state of charge of the ESS is below a first threshold, and the target engine speed is above the current engine speed, the ramp rate may be greater (i.e., faster) than the ramp rate for the same current engine speed and target engine speed when the state of charge of the ESS is above the first threshold. If the ESS power limit is below a first threshold, and the target engine speed is below the current engine speed, the ramp rate may be less (i.e., slower) than the ramp rate for the same current engine speed and target engine speed when the ESS power limit is above the first threshold. Similarly, if the state of charge of the ESS is below a first threshold, and the target engine speed is below the current engine speed, the ramp rate may be less (i.e., slower) than the ramp rate for the same current engine speed and target engine speed when the state of charge of the ESS is above the first threshold.

[0090] At operation 316 of the method 300, the engine and the ESS are controlled, for example, to cooperatively output an amount of power equal to or substantially equal to the power demand. The engine and the ESS may be controlled based on the power demand, the determined target engine speed, and the determined ramp rate. For example, after receiving a power demand and determining the target engine speed, the engine controller 218 may control the engine 102 to increase the engine speed at the determined ramp rate until the engine speed reaches the target engine speed. At the same time, the hybrid system controller 156 may control the ESS 152 to supply the difference between the power demand and the electrical power generated by the rotation of the engine 102 (e.g., via the alternator 104). Thus, the power demand may be met quickly by the combined power output by the engine 102 and the ESS 152 while the engine speed of the engine 102 increases at the ramp rate to the target engine speed. If the engine 102 does not produce enough power to meet the power demand after reaching the target engine speed, the ESS 152 may be controlled to continue supplying power to meet the power demand. If the engine 102 is able to meet the power demand at the target engine speed, the ESS 152 may be controlled to stop supplying power.

[0091] Based on the foregoing, an example of method 300 may be described as follows. An operator of a mine truck depresses an accelerator pedal, requesting that motors driving the drive wheel of the mine truck rotate faster and the mine truck accelerates. A controller of the mine -34- 4928-7931-6870.1Attny Docket No. 106389-9673truck determines the speed that the motor must spin to accelerate the mine truck an amount corresponding to the amount that the accelerator pedal has been depressed. Based on this determined speed and the power required to operate the other components of the mine truck, the controller determines a power demand corresponding to the total amount of electrical power demanded by the mine truck. Based on the power demand, the controller determines an engine speed at which the engine, via the alternator, will provide an amount of power equal to the power demand (a target engine speed). The controller receives engine parameters and / or turbo parameters and determines a power demand bias. The controller also receives parameters for the ESS (e.g., a state of charge, a state of health, etc.) and determines an ESS power output limit. Based on the current engine speed, the target engine speed, the ESS power output limit, and the power demand bias, the controller determines a ramp rate for the engine. The controller (or another controller) causes the engine to increase the engine speed at the determined ramp rate. While the engine speed is ramping up, the ESS is controlled to supply an amount of power equal to the difference between the power demand and the amount of power output by the engine. Thus, when the vehicle demands power, the ESS can be utilized as the primary source of transient power while the engine ramp rate is reduced.

[0092] FIG. 8 shows a graph 800 of various parameters of the power system 100 during a ramp-up period 802 and a ramp-down period 804. During the ramp-up period 802, the unadjusted engine speed command 806 increases from a first engine speed (800 RPM) to a second engine speed (1800 RPM). The unadjusted engine speed command 806 refers to the engine speed that the engine is commanded to reach at the end of the ramp-up period 802. For example, the second engine speed (1800 RPM) may correspond to the “target engine speed” discussed above. It should be understood that these values are exemplary, and that, during a ramp-up period 802, the unadjusted engine speed command 806 may be increased from and / or to different values. The ramped speed 808 shows the actual speed of the engine during the ramp-up period 802 in a system including an ESS that also provides power during the ramp-up period 802 (i.e., a system in accordance with the embodiments described herein). For example, the ramped speed 808 may show the actual speed of the engine during the ramp-up period 802 when an ESS is providing some of the power to the motor of the vehicle. For comparison, the baseline engine speed 810 shows the actual speed of the engine in a system in which the ESS -35- 4928-7931-6870.1Attny Docket No. 106389-9673does not provide power to the motor during the ramp-up period 802. As shown in the graph 800, the baseline engine speed 810 increases from the first engine speed (800 RPM) to the second engine speed (1800 RPM) in a first amount of time (about 10 seconds). This ramp rate is a function of engine and alternator inertia and air-handling response time. In contrast, the ramped engine speed 808 is controlled to increase from the first engine speed (800 RPM) to the second engine speed (1800 RPM) in a second, longer amount of time (about 20 seconds). Thus, the ramp rate for the ramped engine speed 808 is less (slower) than the ramp rate for the baseline engine speed 810. The state of charge 812 of the ESS in the system in accordance with the embodiments described herein is also shown in the graph 800. In the ramp-up period 802, the state of charge of a battery in the ESS decreases from a first state of charge (40 percent) to a second, lower state of charge (30 percent) as the ESS outputs power. Once the engine reaches the target engine speed, the ESS may stop outputting power.

[0093] In the ramp-down period 804, the unadjusted engine speed command 806 decreases from the second engine speed (1800 RPM) back to the first engine speed (800 RPM). It should be understood that these values are exemplary, and that, during a ramp-down period 804, the unadjusted engine speed command 806 may be decreased to and / or from different values. As shown, the baseline engine speed 810 decreases from the second engine speed (1800 RPM) to the first engine speed (800 RPM) in a third amount of time (about 4 seconds), and the ramped engine speed 808 decreases from the second engine speed (1800 RPM) to the first engine speed (800 RPM) in a fourth, longer amount of time (about 8 seconds). During the ramp-down period 804, the ramped engine speed 808 remains higher than the unadjusted engine speed command 806, thus outputting more power than is demanded, for example, by the motor. The excess power during the ramp-down period 804 is supplied to the battery pack of the ESS. As shown in the graph 800, the state of charge 812 of the ESS increases from the second state of charge (30 percent) to a third state of charge (36 percent) as the excess power generated by the engine during the ramp-down period 804 is supplied to the ESS.

[0094] 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 -36- 4928-7931-6870.1Attny Docket No. 106389-9673should 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.

[0095] 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).

[0096] 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).

[0097] 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-37- 4928-7931-6870.1Attny Docket No. 106389-9673embodiments, and that such variations are intended to be encompassed by the present disclosure.

[0098] While various circuits with particular functionality are shown in FIGS. 3 and 4, it should be understood that the vehicle controller 140, the hybrid system controller 156, or the engine controller 218 may include any number of circuits for completing the functions described herein. For example, the activities and functionalities of the circuits 210, 212, 214 may be combined in multiple circuits or as a single circuit. Additional circuits with additional functionality may also be included. Further, the controllers 140, 156, 218 may further control other activity beyond the scope of the present disclosure.

[0099] As mentioned above and in one configuration, the “circuits” may be implemented in machine-readable medium for execution by various types of processors, such as the processors 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.

[0100] 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 -38- 4928-7931-6870.1Attny Docket No. 106389-9673core 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.

[0101] Embodiments within the scope of the present disclosure include program products comprising computer or machine-readable media for carrying or having computer or machineexecutable 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.-39- 4928-7931-6870.1Attny Docket No. 106389-9673

[0102] 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.

[0103] 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.

[0104] 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).-40- 4928-7931-6870.1Attny Docket No. 106389-9673

[0105] 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.

[0106] 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.

[0107] 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.-41- 4928-7931-6870.1

Claims

Attny Docket No. 106389-9673WHAT IS CLAIMED IS:

1. A system comprising:a controller communicably coupled to an internal combustion engine and an energy storage system, the controller comprising at least one processor coupled to at least one memory device storing instructions that, when executed by the at least one processor, cause the controller to perform operations comprising:receiving a power demand;determining a target engine speed based on the power demand; determining an engine speed ramp rate based on a power limit of the energy storage system and the target engine speed; andadjusting an engine speed of the internal combustion engine to the determined engine speed at the determined engine speed ramp rate.

2. The system of claim 1, wherein the instructions, when executed by the at least one processor, further cause the controller to perform operations comprising causing the internal combustion engine to increase to the target engine speed at the engine speed ramp rate.

3. The system of claim 2, wherein the instructions, when executed by the at least one processor, further cause the controller to perform operations comprising determining a difference in power between the power demand and an amount of electrical power generated using rotation of the engine and causing the energy storage system to output the difference in power.

4. The system of claim 1, wherein the instructions, when executed by the at least one processor, further cause the controller to perform operations comprising determining the power limit of the energy storage system based on a state of charge of an energy storage device of the energy storage system.-42- 4928-7931-6870.1Attny Docket No. 106389-96735. The system of claim 4, wherein determining the power limit of the energy storage system is based on at least one of a state of health or a temperature of the energy storage device.

6. The system of claim 4, wherein:in response to the target engine speed being greater than a current engine speed, the engine speed ramp rate is negatively correlated with the state of charge of the energy storage device; andin response to the target engine speed being less than the current engine speed, the engine speed ramp rate is positively correlated with the state of charge of the energy storage device.

7. The system of claim 1, wherein the instructions, when executed by the at least one processor, further cause the controller to perform operations comprising receiving an indication that an operating parameter is at or above predefined threshold, the operating parameter comprising one of an engine speed, an engine exhaust temperature, a peak cylinder pressure of the engine, or a turbo speed or a turbo temperature of a turbo device coupled to the engine, and, based on receiving the indication, reducing the engine speed and causing the energy storage system to output power.

8. The system of claim 1, wherein the power demand corresponds to an amount of electrical power demanded for performing one more functions of an electrical system.

9. The system of claim 1, further comprising an alternator configured to convert rotational energy from the internal combustion engine into electric power, wherein the instructions, when executed by the at least one processor, further cause the controller to perform operations comprising causing the internal combustion engine, via the alternator, and the energy storage system to cooperatively output an amount of power equal to or substantially equal to the power demand while the engine speed increases to the target engine speed.-43- 4928-7931-6870.1Attny Docket No. 106389-967310. A system comprising:an energy storage system electrically coupled to an electrical system; andat least one processing circuit coupled to the energy storage system, the at least one processing circuit including at least one processor coupled to at least one memory device storing instructions that, when executed by the at least one processor, cause the at least one processor to perform operations comprising:receiving a power demand for operating the system;determining a target engine speed for an internal combustion engine based on the power demand;determining an engine speed ramp rate based on a power limit of the energy storage system and the target engine speed for the internal combustion engine; and adjusting an engine speed of the internal combustion engine based on the determined ramp rate.

11. The system of claim 10, wherein the instructions, when executed by the at least one processor, further cause the at least one processing circuit to perform operations comprising causing the internal combustion engine and the energy storage system to cooperatively output an amount of power equal to or substantially equal to the power demand to the electrical system while the engine speed increases to the target engine speed.

12. The system of claim 11, wherein the system is a vehicle, and the electrical system comprises at least one motor configured to drive the vehicle.

13. The system of claim 10, wherein the power limit of the energy storage system is an output power limit, and adjusting the engine speed comprises causing the engine speed to increase relative to a current engine speed.-44- 4928-7931-6870.1Attny Docket No. 106389-967314. The system of claim 10, wherein the power limit of the energy storage system is an input power limit, and adjusting the engine speed comprises causing the engine speed to decrease relative to a current engine speed.

15. A method of controlling a hybrid power system comprising an internal combustion engine and an energy storage system, the method comprising:determining, by a controller, a target engine speed of the internal combustion engine based on a power demand on the system;determining, by the controller and based on the target engine speed, a current engine speed of the internal combustion engine, and a power limit of the energy storage system, a ramp rate for changing an engine speed of the internal combustion engine from the current engine speed to the target engine speed; andincreasing, by the controller, the engine speed from the current engine speed to the target engine speed at the determined ramp rate.

16. The method of claim 15, further comprising determining a difference in power between the power demand and a power output of the internal combustion engine and causing the energy storage system to output an amount of power substantially equal to the difference in power.

17. The method of claim 15, further comprising determining a difference in power between the power demand and a power output of the internal combustion engine, causing an alternator to generate an amount of electrical power substantially equal to the difference in power using rotational energy from the internal combustion engine, and storing the generated electrical power in the energy storage system.

18. The method of claim 15, further comprising:reducing, by the controller, the engine speed to a reduced engine speed below the target engine speed upon determining that an operating parameter is at or above predefined threshold, the operating parameter comprising one of an engine speed, an engine exhaust temperature, a-45- 4928-7931-6870.1Attny Docket No. 106389-9673peak cylinder pressure of the internal combustion engine, or a turbo speed or a turbo temperature of a turbo device coupled to the internal combustion engine;determining, by the controller, a reduced power output of the internal combustion engine at the reduced engine speed; andcausing, by the controller, the energy storage system to output an amount of power substantially equal to a difference between the power demand and the reduced power output of the internal combustion engine.

19. The method of claim 15, wherein the power limit of the energy storage system is based in part on an amount of regenerative braking power supplied to the energy storage system.

20. The method of claim 15, wherein the power produced by the internal combustion engine at the target engine speed is less than the power demand, the method further comprising causing, by the controller, the energy storage system to output power while the internal combustion engine operates at the target engine speed.-46- 4928-7931-6870.1

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