Dual fuel engine system and method for controlling a dual fuel engine system

Abstract

A method for controlling a dual fuel engine system includes estimating a total indicated engine load, where the total indicated engine load is based on a sum of a measured engine power and a power loss estimate. The method further includes determining a total fuel charge based on the engine speed and the total indicated engine load, wherein the total fuel charge includes a gaseous fuel charge and a diesel fuel charge. The method also includes controlling the dual fuel engine system using the total fuel charge.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Patent Application Nos. 17 / 944,910, 17 / 944,900, and 17 / 944,905, filed on September 14, 2022, each of which is incorporated herein by reference in its entirety.

[0003] background

[0004] The present disclosure generally relates to methods for controlling a dual fuel engine system.

[0005] Generally, a dual fuel engine system may include an original equipment manufacturer (OEM) machine control system, a base engine control system or module (ECM) operably coupled to the OEM, and a gas control system operably coupled to both the OEM machine control system and the base engine control system.

[0006] Overview

[0007] One aspect of the present disclosure relates to a method for controlling a dual-fuel engine system. The method includes estimating a total indicated engine load, the total indicated engine load being based on a sum of a measured engine power and a power loss estimate. The method also includes determining a total fueling amount based on an engine speed and the total indicated engine load, the total fueling amount including a gas fueling amount and a diesel fueling amount. The method also includes using the total fueling amount to control the dual-fuel engine system.

[0008] Another aspect of the present disclosure relates to a method for controlling a dual fuel engine system. The method includes estimating a total indicated engine load, the total indicated engine load being based on a sum of measured engine power, a friction power estimate, and an accessory power estimate. The method includes determining a total fueling amount from a first lookup table, the lookup table being based on engine speed and the total indicated engine load. The method also includes determining at least one updated total fueling amount based on the total fueling amount and an operating state of a dual fuel mode switch within the dual fuel engine system. The method also includes determining a control input for at least one actuator within the dual fuel engine system, wherein the control input is based on selecting a corresponding lookup table set associated with the at least one actuator, the lookup table set comprising a plurality of lookup tables, each of the plurality of lookup tables being based on engine speed and at least one updated total fueling amount.

[0009] Another aspect of the present disclosure relates to a dual fuel engine system. The system includes an internal combustion engine operable in a dual fuel mode, at least one actuator operably coupled to the internal combustion engine, and at least one controller in communication with the internal combustion engine and the at least one actuator. The at least one controller is configured to perform the following operations: receive a first input corresponding to an engine speed and a second input corresponding to a measured engine power, calculate a power loss estimate, determine a total fueling amount based on the measured engine power and the power loss estimate, determine a first diesel fuel command associated with the internal combustion engine based at least on a calculated governor command and the power loss estimate, and determine at least one updated total fueling amount based on the total fueling amount and the first diesel fuel command. The at least one controller is also configured to select a lookup table set associated with the at least one actuator based on a gas substitution rate associated with the internal combustion engine, the lookup table set being based on the engine speed and the at least one updated total fueling amount. The controller is also configured to send an input to the at least one actuator based on the lookup table set.

[0010] This summary is illustrative only and is not to be construed as limiting. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present disclosure will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which like reference numerals refer to like elements, and in which:

[0013] Figure 1 is a block diagram of a dual fuel engine system according to an exemplary embodiment.

[0014] Figure 2 According to an exemplary embodiment Figure 1 Block diagram of the control system of a dual-fuel engine system.

[0015] Figure 3 is a diagram showing a method of performing a Figure 2 A flow chart of a method performed by a control system.

[0016] Figure 4 is a diagram showing a method of performing a Figure 2 A flow chart of a method performed by a control system.

[0017] Figure 5 is a diagram showing a method of performing a Figure 2 A flow chart of a method performed by a control system.

[0018] Figure 6 is a diagram showing a method of performing a Figure 2 A flow chart of a method performed by a control system.

[0019] Figure 7is a diagram showing a method of performing a Figure 2 A flow chart of a method performed by a control system.

[0020] Figure 8 is a diagram showing a method of performing a Figure 2 A flow chart of a method performed by a control system.

[0021] Fig. 9 is a diagram showing a method of performing a Figure 2 A flow chart of a method performed by a control system.

[0022] Detailed Description

[0023] In the following detailed description, reference is made to the accompanying drawings, which form a part thereof. In the accompanying drawings, similar symbols generally identify similar parts unless the context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be employed and other changes may be made without departing from the spirit or scope of the subject matter described herein. It will be readily understood that the various aspects of the present disclosure, as generally described herein and illustrated in the accompanying drawings, may be arranged, substituted, combined, and designed in a variety of different configurations, all of which are contemplated and form a part of the present disclosure.

[0024] The present disclosure relates at least in part to systems and methods for providing reduced operating costs, improved efficiency and / or improved performance of dual-fuel engine systems. In some embodiments, such systems and methods allow target emission levels to be met. In some embodiments, the scheme for controlling the dual-fuel system is adjustable to simplify the interfacing between the diesel engine ECM, the gas controller, and the OEM controller. In various embodiments, the dual-fuel engine system (and associated operating methods) is customized to maximize the use of cheaper gaseous fuels and minimize the use of diesel fuels while meeting performance requirements and emission requirements and maintaining robust engine protection. In particular, in order to meet Tier 4 emission regulations with a dual-fuel engine system, it is necessary to accurately and robustly control the dual-fuel engine system. This accurate and robust control includes, but is not limited to, control of the following: a gaseous fuel system, a diesel fuel system, and an aftertreatment system included in the dual-fuel engine system. The present disclosure outlines a system and method for precise and robust control of a dual-fuel engine system, including accurately determining (e.g., by measurement or estimation) multiple engine parameters (e.g., brake power, friction power, accessory power, diesel power, gas power, gas substitution rate, methane number, LHV, gas temperature, gas pressure, knock intensity, exhaust temperature, etc.), and using the determined parameters as inputs for determining appropriate commands for one or more actuators within the dual-fuel engine system. The systems and methods described herein are applicable to new engine constructions or for retrofitting onto existing Tier 4 diesel engine systems. Advantageously, the systems and methods described herein are lower in cost and complexity than typical port gas injection or cylinder pressure sensing systems.

[0025] refer to Figure 1 , a block diagram of a dual fuel engine system 10 according to an exemplary embodiment is shown. The dual fuel engine system 10 is configured as an engine having a dual fuel operating mode, the engine being configured to operate using two different fuels. In various embodiments, the fuels may include diesel and natural gas. In various embodiments, the dual fuel engine system 10 is configured for one or more oil and gas production applications (e.g., land-based oil and / or gas drilling and hydraulic fracturing). Figure 1As shown, the dual fuel engine system includes an internal combustion engine 20, which is operably coupled to the control system 11 via at least one controller 18. The control system 11, including the machine control system (OEM system) 12, the diesel control system 14, and the gas control system 16, is configured to send one or more inputs to the controller 18, wherein the controller 18 then controls the internal combustion engine 20. In various embodiments, the controller 18 is configured to include a processor and a non-transitory computer-readable medium (e.g., a memory device) having computer-readable instructions stored thereon, which when executed by the processor causes the at least one controller 18 to perform one or more operations. In various embodiments, the at least one controller 18 is a computing device (e.g., a microcomputer, a microcontroller, or a microprocessor). In other embodiments, the at least one controller 18 is configured as part of a data cloud computing system that is configured to receive commands from a user control device and / or a remote computing device.

[0026] The controller 18 is also operably coupled to at least one gas injector 28, at least one gas heater 32, and at least one actuator 33. In other embodiments, the dual-fuel engine system 10 does not include a gas heater. In some embodiments, each of the gas injector 28, the heater 32, and the actuator 33 is operably coupled to the internal combustion engine 20. In various embodiments, the gas injector 28 is configured to control or facilitate the injection of gas into the internal combustion engine 20. At least one gas heater 32 is configured to adjust the temperature of the gas flowing within the internal combustion engine 20. The actuator 33 may include one or more diesel-type actuators, air handling actuators, aftertreatment actuators, or any other type of actuator within the dual-fuel engine system 10. Therefore, during operation, the controller 18 may send one or more inputs to one or more of the internal combustion engine 20, the gas injector 28, the heater 32, or the actuator 33 to facilitate the desired operating mode of the dual-fuel engine system 10.

[0027] As shown, the internal combustion engine 20 includes an output shaft 24 and may also include one or more accessories 22. The internal combustion engine 20 also includes at least one manifold 26. In various embodiments, the at least one manifold 26 includes, but is not limited to, an intake manifold. The internal combustion engine 20 also includes at least one engine cylinder bank. In some embodiments, the at least one engine cylinder bank includes a left bank 30 and a right bank 31. During operation of the dual-fuel engine system 10, the control system 11 may receive one or more inputs from a user and / or one or more sensors within the dual-fuel engine system 10, and control the operation of at least one of the internal combustion engine 20, the gas injector 28, or the actuator 33 via the controller 18.

[0028] Figure 2 is a block diagram of a control system 11 of a dual fuel engine system 10, according to an exemplary embodiment. As shown, the OEM system 12 may include one or more sensors 35, each coupled to one or more corresponding components within the dual engine system 10. In various embodiments, the one or more sensors 35 may be operably coupled to or in communication with: a frac pump, accessories, one or more inlets or outlets of the internal combustion engine 20, or any other component within the dual fuel engine system 10 (e.g., a cooling fan, a flywheel, a brake, etc.). The OEM system 12 may include one or more processors configured to receive inputs from the sensors 35. In various embodiments, the one or more inputs from the sensors 35 may include a power estimate, a frac pump speed, a frac pump discharge pressure, a dual fuel mode activation request, or any other input detectable by the one or more sensors 35. As shown, the OEM system 12 is communicatively coupled to each of the diesel control system 14 and the gas control system 16 , wherein the OEM system 12 may output information sensed by one or more sensors 35 or may receive input from the diesel control system 14 and / or the gas control system 16 .

[0029] like Figure 2 As shown, the diesel control system 14 includes one or more sensors 40, which are coupled to one or more components within the internal combustion engine 20 or are arranged adjacent to one or more components within the internal combustion engine 20. In various embodiments, the one or more sensors 40 can be configured to determine (e.g., sense, detect, measure) at least one of the following: engine speed, intake manifold temperature, engine coolant temperature, oil temperature, cooling fan duty cycle, diesel fuel rate, or the operating state of the dual fuel mode switch 55. In various embodiments, the dual fuel mode switch 55 can be configured to switch the operation of the internal combustion engine 20 between a single fuel mode or a dual fuel mode. Additionally or alternatively, the one or more sensors 40 can be configured to determine the lower heating value (LHV) of the gas. In other embodiments, the one or more sensors 40 can be configured to determine one or more parameters indicating the LHV, which can include but are not limited to gas density or sound speed. The diesel control system 14 also includes an engine governor 50. In various embodiments, engine speed governor 50 may include one or more controllers configured to control the speed of internal combustion engine 20 .

[0030] The diesel control system 14 also includes a diesel engine control system (ECM) and a torque fueling calculation module 45. In various embodiments, the torque fueling calculation module 45 may include one or more processors in communication with one or more reference databases or repositories, wherein the one or more processors are configured to reference data stored in the databases in order to perform torque calculations associated with the internal combustion engine 20. For example, in various embodiments, the torque fueling calculation module 45 is configured to calculate torque based on one or more known parameters. In various embodiments, the module 45 is configured to receive inputs corresponding to: dual fuel mode operating conditions, engine friction parameters, accessory ("parasitic") torque parameters, engine speed, OEM machine power estimates, and engine accessory power estimates (e.g., gas controller, flywheel, etc.). In various embodiments, the one or more reference databases or repositories may include a lookup table 65. In various embodiments, the one or more lookup tables 65 include one or more chi-square tables. In various embodiments, the lookup table 65 may include reference information related to the following items: engine torque, engine speed, engine friction parameters, parasitic torque parameters or accessory torque parameters, diesel fuel rate, intake manifold temperature and / or engine coolant temperature. In various embodiments, the engine friction parameters of the lookup table 65 may be based on at least one of the oil temperature or the coolant temperature. In some embodiments, the parasitic parameters or torque parameters of the lookup table 65 may be based on the cooling fan duty cycle (i.e., the cooling fan duty cycle of the cooling fan in the internal combustion engine 20). In various embodiments, the module 45 is configured to determine at least one of the following: total diesel fuel fill, "fast" equivalent total fuel fill, equivalent total fuel fill (i.e., the gaseous fuel fill equivalent of the diesel fuel fill), friction torque estimate, or diesel fuel rate.

[0031] The diesel control system 14 also includes a diesel air handling, aftertreatment and fuel system reference determination and control module 60. In various embodiments, the control module 60 may include at least one processor in communication with a database (e.g., a lookup table) 75. In various embodiments, the database 75 includes a data repository related to the following items: engine speed, fuel fill (e.g., equivalent total fuel fill, fast equivalent total fuel fill), gas substitution rate (G / D), compressor inlet density (CID), or any other relevant parameters. Therefore, one or more processors within the control module 60 are configured to reference the data stored in the database 75 to determine one or more system inputs for at least one of the air handling control system 80, the aftertreatment control system 85, or the diesel fuel control system 90. In various embodiments, the one or more system inputs include, but are not limited to, actuator commands or targets (e.g., set points, operating thresholds, etc.) for at least one of the diesel air handling control system 80, the aftertreatment control system 85, or the diesel fuel control system 90.

[0032] like Figure 2As shown, the gas control system 16 may include one or more sensors 95 coupled to one or more components within the internal combustion engine 20 or disposed adjacent to one or more components within the internal combustion engine 20. In various embodiments, the one or more sensors 95 may be configured to determine (e.g., sense, detect, measure, etc.) at least one of the following: OEM machine torque, accessory torque, methane number (MN), gas injector pressure, gas supply pressure, gas flow, engine group exhaust temperature, aftertreatment system temperature, LHV, gas temperature, dual fuel mode input, knock intensity, G / D, or any other relevant parameter. In some embodiments, the engine group exhaust temperature may correspond to the left group average exhaust temperature and / or the right group average exhaust temperature. In some embodiments, the group average exhaust temperature may be calculated by averaging the measurements from the various exhaust port temperature sensors. In some embodiments, the exhaust port temperature sensor may be among the at least one sensor 35, 40, and / or 95. The gas control system 16 also includes an OEM machine power and accessory power estimation module 130. In various embodiments, the OEM machine power and accessory power estimation module 130 may include one or more processors configured to estimate the OEM machine power and / or accessory power based on one or more inputs received by one or more sensors 95 (and / or from sensors 35, 40). In some embodiments, the accessory power may be power associated with one or more accessory components and / or output shafts (e.g., output shaft 24) within the dual-fuel engine system 10. In various embodiments, the OEM machine power and accessory power estimation module 130 is configured to receive inputs related to the OEM machine power estimate, accessory torque measurements, pump speed, pump discharge pressure, and engine speed, wherein one or more processors then estimate the accessory power estimate based on the inputs. Similarly, the gas control system 16 also includes a MN estimation module 125. In various embodiments, the MN estimation module 125 may include one or more processors configured to estimate the MN associated with the internal combustion engine 20 based on one or more inputs received by one or more sensors 95 (and / or from sensors 35, 40). In various embodiments, at least one of the sensors 35, 40, or 90 may be distributed or divided to any different control system (e.g., OEM system 12, diesel control system 14, gas control system 16) within the dual fuel engine system 10 without changing the overall functionality of the sensor. For example, in various embodiments, the sensor 95 may be included within or operably coupled to any of the following: the OEM system 12, the diesel control system 14, or the gas control system 16.Similarly, sensor 35 may be included in or operably coupled to any of the following: OEM system 12, diesel control system 14, or gas control system 16. Sensor 40 may also be included in or operably coupled to any of the following: OEM system 12, diesel control system 14, or gas control system 16.

[0033] The gas control system 16 also includes an indicated engine power and gas estimation module 115. The engine power and gas estimation module 115 may include one or more processors configured to receive one or more inputs related to the operation of the dual fuel engine system 10. The engine power and gas estimation module 115 may also be configured to use a database 170 and / or a torque-to-power calculation system 175 to determine at least one of the following: a thermal efficiency estimate, a first gas power estimate, an indicated diesel power estimate, a net engine power estimate, an intake manifold temperature (e.g., a maximum intake manifold temperature), and / or other related parameters. In various embodiments, the database 170 is a lookup table. In some embodiments, the torque-to-power calculation system 175 may be or include computer logic. In various embodiments, the engine power and gas estimation module 115 is configured to receive one or more inputs corresponding to: a G / D estimate, a friction torque estimate, an accessory ("parasitic") torque estimate, a diesel fuel rate, an engine speed, an intake manifold temperature, and / or a MN estimate. In an embodiment, the MN estimate is determined by the MN module 125. Although the terms "torque" and "power" are used in various contexts throughout this disclosure, it should be understood that in various embodiments, torque may be used in place of power, or power may be used in place of torque. For example, it should be understood that power may be calculated based on torque and speed, or vice versa. In yet other embodiments, any other parameter indicative of load (e.g., alternatively or in addition to torque and / or power) may be determined and / or used in the operations performed by the control system 11.

[0034] The gas control system 16 also includes a gas LHV and G / D estimation module 120. The LHV and G / D estimation module 120 may include a gas power selector switch 185, an LHV learning algorithm 180 configured to process one or more received inputs, and a power rationality diagnostic and protection module 190. In various embodiments, the LHV learning algorithm 180 includes a filter (e.g., a low-pass filter, a moving average filter, etc.) and / or an adaptive learning routine. In some embodiments, one or more inputs are received from the sensor 95. The LHV and G / D estimation module 120 may include one or more processors configured to receive inputs including: a total gas flow estimate (i.e., of the gas flowing within the engine system 10), a thermal efficiency estimate, an indicated diesel power estimate, and a first indicated engine power estimate. In various embodiments, one or more processors of the LHV and G / D estimation module 120 may receive inputs from sensors 35, 40, and / or 95. The LHV and G / D estimation module 120 can thereby estimate the G / D amount and the LHV amount associated with the internal combustion engine 20. In various embodiments, one or more processors within the LHV and G / D estimation module 120 can determine the LHV and G / D estimates by multiplying the total gas flow estimate by the thermal efficiency estimate and using the result to normalize the first gas power estimate (e.g., by dividing the first gas power estimate by the product of the total gas flow estimate and the thermal efficiency estimate) to determine the instantaneous LHV amount. The LHV learning algorithm 180 can process the instantaneous LHV amount to then determine (i.e., learn) the LHV estimate. In various embodiments, the gas power selector switch 185 can be configured to receive inputs corresponding to the first power estimate and the second power estimate. In some embodiments, the gas power selector switch 185 can also be configured to output a final gas power estimate using the first power estimate and the second power estimate. In various embodiments, the final gas power estimate is based on the maximum or minimum of the first power estimate and the second power estimate. In various embodiments, the power rationality diagnostic and protection module 190 may include one or more processors configured to receive input corresponding to the first indicated engine power estimate and the second indicated engine power estimate. In some embodiments, the power rationality diagnostic and protection module 190 is further configured to initiate one or more diagnostic operations or engine protection protocols based on and in response to a comparison of one or both of the first indicated engine power estimate and the second indicated engine power estimate with one or more threshold values.

[0035] As shown, the gas control system 16 also includes a G / D target automatic compensation module 105. In various embodiments, the G / D target automatic compensation module 105 is configured to adjust or compensate the G / D target of the internal combustion engine 20. The module 105 is configured to receive one or more inputs indicating engine speed, engine load (e.g., power, torque, etc.), intake manifold temperature, and / or MN estimation. In various embodiments, the module 105 receives one or more inputs from sensors 95, 35, and / or 40. In some embodiments, the one or more inputs received by the module 105 are processed by a speed-based G / D target interpolation unit 135 to determine the G / D target based on the indicated engine speed. In various embodiments, the speed-based G / D target interpolation unit 135 uses data stored in one or more databases 145 to determine the G / D target based on the indicated engine speed. In some embodiments, the one or more databases 145 may include one or more lookup tables. The module 105 also includes a G / D target limiter 140, which includes one or more processors configured to determine a G / D target limit value based on one or more inputs. In various embodiments, the one or more inputs may include engine knock, exhaust temperature, and / or diesel fuel quantity. In various embodiments, the exhaust temperature corresponds to the exhaust temperature of the engine bank. The gas control system 16 may use the G / D target limit value and the first indicated engine power estimate value to determine the gas power target value.

[0036] like Figure 2 As shown, the gas control system 16 includes a gas injector control module 110, which includes at least one G / D proportional-integral-derivative (PID) controller 150. In various embodiments, the PID controller 150 is configured to receive a feedforward input based on a gas flow target compensated for gas injector pressure and temperature. In various embodiments, the gas injector pressure and temperature can be measured by sensors 95, 35 and / or 40. The controller 150 can also receive a feedback input corresponding to a G / D estimate and a target input corresponding to the G / D controller. In response to receiving the feedforward input, the feedback input and the target input, the PID controller 150 can output at least one basic gas injector command. In various embodiments, the at least one basic gas injector command is associated with at least one engine group gas injector command. In some embodiments, the at least one engine group gas injector command includes a left group gas injector command and / or a right group gas injector command.

[0037] The gas injector command converter 160 may be operably coupled to the PID controller 150. In various embodiments, the gas injector command converter 160 may include one or more processors configured to convert the basic gas injector command into at least one engine group gas injector command. The gas injector control module 110 may also include a group balancing PID controller 155. In various embodiments, the PID controller 155 is configured to receive feedback inputs corresponding to the following items: the exhaust temperature difference between the left group (e.g., left group 30) of the internal combustion engine 20 and the right group (e.g., right group 31) of the internal combustion engine 20, and a target value associated with the exhaust temperature difference. In various embodiments, the target value is zero. In response to the feedback input and the target input, the PID controller 155 is configured to output a left group correction amount and a right group correction amount. In various embodiments, one or both of the left group correction amount and the right group correction amount may be a positive value or a negative value. The output left group correction amount and right group correction amount can each be added to the basic gas injector command (e.g., the output from PID 150), and the gas injector command converter 160 can convert it into the corresponding left group gas injector command and right group gas injector command. The gas flow estimator 165 is configured to receive each of the left group gas injector command and the right group gas injector command as well as the gas pressure and the gas temperature. In various embodiments, the gas flow estimator 165 may include or be coupled to one or more processors within the module 110. In some embodiments, the gas pressure and / or gas temperature are measured by sensors 95, 35 and / or 40. In various embodiments, the gas flow estimator 165 is configured to output a total gas flow estimate associated with the internal combustion engine 20 based on the left group gas injector command and the right group gas injector command, the gas pressure and the gas temperature.

[0038] Finally, if Figure 2As shown, the gas control system 16 includes a gas heater control module 100. In various embodiments, the gas heater control module 100 is configured to control the operating state of at least one heater 32 coupled to the internal combustion engine 20. In various embodiments, the gas heater control module 100 includes one or more processors configured to receive one or more inputs from at least one controller 18 and / or from other components within the control system 11. One or more processors within the gas heater control module 100 can be configured to cause the gas heater control module 100 to change the operating state of at least one heater 32. In some embodiments, changing the operating state of at least one heater 32 can include adjusting the operating setting of the heater control valve 195 to control the operating state of at least one heater 32. In various embodiments, at least one heater 32 can be an electric heater. In other embodiments, at least one heater 32 can be configured to use engine coolant to provide heat.

[0039] In various implementations, the engine control system 11 including the OEM system 12 , the diesel control system 14 , and the gas control system 16 may cooperate to control the dual fuel engine system 10 . Figure 3 A flow chart is shown that illustrates a method 300 for controlling a dual fuel engine system 10 according to an exemplary embodiment. In operation 305, the engine control system 11 estimates the total engine load (e.g., power, torque, etc.) of the internal combustion engine 20. In various embodiments, the OEM system 12 calculates the total engine load by determining a first load amount ("primary load") transmitted through the engine (e.g., via a flywheel, a frac pump load, etc.) and broadcasting the determined first load to the diesel control system 12 and / or the gas control system 16 (e.g., via a data link). In embodiments where the OEM system 12 controls accessory loads ("secondary loads", such as cooling fan loads) within the diesel fueled engine system 10, the OEM system 12 may estimate the accessory load, add the accessory load to the first load amount, and then broadcast the sum indicating the total engine load to the system 14 and / or 16 (e.g., via a data link). In operation 310, the control system 11 may determine the total fuel charge of the internal combustion engine 20. The control system 11 may then control the dual fuel engine system 10 in operation 315 using the total fuel charge determined in operation 310 .

[0040] In various implementations, the control system 11 may estimate the total engine load (e.g., power, torque, etc.). In some implementations, the control system 11 estimates the total engine load in operation 305 by measuring engine power in operation 320, estimating power loss in operation 325, and determining the sum of the measured engine power and the estimated power loss in operation 330. In some embodiments, the estimated total engine load may be based on input received from the OEM system 12 (e.g., from one or more sensors that may sense at least one of pump discharge pressure, speed, current, or voltage) in response to an external load or indicative of an external load. The OEM system 12 may then use the input (i.e., the sensed information) to calculate the engine load. The OEM system 12 may then output the calculated load value to the gas control system 16 and / or the diesel control system 14 using a data link signal and / or an analog signal (e.g., 4 mA-20 mA). In some embodiments, the external load corresponds to at least one of a generator or a pump operably coupled to the internal combustion engine 20. In various implementations, the engine control system 11 may determine the total fuel fill in operation 310. In some implementations, the control system 11 determines the total fueling amount in operation 310 based at least in part on the measured engine speed 335 and the calculated governor indicated torque demand 340. Figure 4 As shown, in various implementations, controlling the dual fuel engine system 10 in operation 315 may include determining an updated total fuel fill amount in operation 345, and determining at least one control input for at least one actuator 33 in operation 350. In various embodiments, at least one actuator 33 may be a diesel fuel system actuator. In various implementations, the updated total fuel fill amount determined in operation 345 may be based on determining the operating state of the dual fuel mode switch 55 in operation 355. In various embodiments, the updated fuel fill amount determined in operation 345 includes a first updated fuel fill amount and a second updated fuel fill amount. In some embodiments, the first updated fuel fill amount corresponds to a maximum value between the total fuel fill amount and the diesel fuel command. In some embodiments, the second updated total fuel fill amount is determined by subtracting the diesel fuel command from the first total updated fuel fill amount to determine the diesel fuel equivalent of the gaseous fuel fill amount, and adding the diesel equivalent fuel fill amount to the second diesel fuel command.

[0041] In various implementations, determining the control input for at least one actuator 33 (in operation 350) may be based on selecting a set of lookup tables. Information in the lookup tables may then be referenced when determining the control input. The lookup tables may contain information from one or more of the following: the diesel ECM and torque fueling calculation module 45, the diesel air handling, aftertreatment and fuel system reference determination and control module 60, and / or the indicated engine power and gas power estimation module 115. The selection of the set of lookup tables may be performed in operation 360. In various embodiments, selecting the set of lookup tables in operation 360 includes determining a compressor inlet density (CID) of the internal combustion engine 20. In some embodiments, selecting the set of lookup tables in operation 360 additionally or alternatively includes determining a G / D within the internal combustion engine 20. In other embodiments, selecting the set of lookup tables in operation 360 additionally or alternatively includes determining an operating state of the dual fuel mode switch 55. In some embodiments, selecting the set of lookup tables in operation 360 includes selecting at least one of an air handling reference table, an aftertreatment reference table, or a fueling reference table.

[0042] In various implementations, the control system 11 may determine a maximum amount between the total fuel fill (from operation 310) and the first diesel fuel command. In various embodiments, the first diesel fuel command is determined from the diesel control system 14. In some embodiments, the control system 11 may be configured to determine a second updated total fuel fill. In various embodiments, the second updated fuel fill is determined by subtracting the first diesel fuel command from the first updated total fuel fill to determine the diesel fuel equivalent of the gaseous fuel fill associated with the internal combustion engine, and adding the diesel fuel equivalent of the gaseous fuel fill to the second diesel fuel command to determine the second updated total fuel fill. In various embodiments, the control system 11 may determine at least one actuator command based on the engine speed and at least one of the first updated total fuel fill or the second updated total fuel fill. In some embodiments, the at least one actuator command may be associated with at least one actuator within the air handling control system 80, the aftertreatment control system 85, the diesel fuel control system 90, or the actuator 33.

[0043] In various embodiments, determining the total fueling amount in operation 310 may include referencing one or more torque-fuel lookup tables. In various embodiments, one or more torque-fuel lookup tables are determined or referenced from the diesel ECM and the torque fueling calculation module 45. In various embodiments, the lookup table may be based on the engine speed and the indicated diesel torque input. In some embodiments, the indicated diesel torque input may be determined by sensor 35. In various embodiments, the indicated diesel torque input determined in operation 310 is based on the sum of the friction power estimate and the engine speed torque demand. In some embodiments, the engine speed torque demand corresponds to the difference between the engine speed and a predetermined engine speed target. In various embodiments, the control system 11 determines a power loss estimate in operation 325. In some embodiments, the control system 11 determines the power loss estimate in operation 325 by estimating the amount of friction torque associated with the internal combustion engine 20, estimating the amount of accessory torque, determining the amount of charge air pumping torque, and determining the engine speed. In various embodiments, the engine speed is determined via sensors 35, 40, and / or 95. In various embodiments, the charge air pumping torque amount is an estimate of pumping losses associated with the diesel fuel engine system 10, where the pumping losses correspond to the amount of work done by the engine to draw air into the engine to facilitate combustion and then exhaust the combustion products to the atmosphere. In some embodiments, the charge air pumping torque may be measured using cylinder pressure data determined during engine development. In various embodiments, the data determined during engine development may be used to calibrate a pumping torque virtual sensor (i.e., operably coupled to the OEM system 12, the diesel control system 14, and / or the gas control system 16) configured to sense the charge air pumping torque amount.

[0044] In some implementations, the friction torque estimate can be determined from a lookup table. In various embodiments, the lookup table is determined or referenced from the diesel ECM and torque fuel filling calculation module 45. In some embodiments, the lookup table is based on engine speed and engine friction parameters. In some embodiments, the engine friction parameters can correspond to the oil temperature or coolant temperature within the internal combustion engine 20 of the dual-fuel engine system 10. In various embodiments, the control system 11 can be configured to determine the accessory torque estimate from a lookup table. In various embodiments, the lookup table is determined or referenced from the diesel ECM and torque fuel filling calculation module 45. In some embodiments, the lookup table is based on engine speed and accessory torque parameters. In various embodiments, the accessory torque parameter can correspond to the amount of cooling fan power (e.g., measured or estimated) or duty cycle commanded by the internal combustion engine 20 of the dual-fuel engine system 10.

[0045] In various embodiments, the control system 11 is configured to determine the first diesel fuel command from a torque-fuel lookup table. In various embodiments, the torque-fuel lookup table is determined or referenced from the diesel ECM and the torque fueling calculation module 45. In some embodiments, the torque-fuel lookup table is based on the engine speed (i.e., of the internal combustion engine 20) and the sum of the friction power estimate associated with the internal combustion engine 20 and the torque demand. In various implementations, the torque demand is set by the engine speed governor 50.

[0046] In various embodiments, the control system 11 may be configured to activate one or more protective measures associated with the internal combustion engine 20. In some embodiments, the control system 11 is configured to activate one or more protective measures via the power rationality diagnostic and protection module 190. Figure 5 A method 400 is shown that may be implemented by the control system 11 to activate one or more engine protection measures. In operation 405, the control system 11 is configured to determine an amount of friction power loss. In various implementations, the amount of friction power loss may be determined by measuring the speed of the internal combustion engine 20 in operation 425 and estimating an amount of friction torque in operation 430. After determining the amount of friction power loss in operation 405, the control system 11 may determine an amount of accessory power loss in operation 410. In various embodiments, the amount of accessory power loss may be associated with a load applied by the OEM system 12 (e.g., cooling fan, pump, alternator, etc.) and / or any other accessory component within or coupled to the internal combustion engine 20.

[0047] In various embodiments, the amount of accessory power loss may be based on the measured engine speed (determined in operation 425) and based on the estimated amount of accessory torque determined in operation 435. Using the amount of accessory power loss and the amount of friction power loss, the control system 11 may estimate the amount of net engine power in operation 415. In various embodiments, the amount of net engine power may also be based on the amount of brake power (e.g., engine dynamometer measurements) determined by the control system 11 in operation 440. Using the estimated amount of net engine power determined in operation 415, the control system 11 may estimate the first indicated engine power and the first gas power amount in operation 420. In various embodiments, the control system 11 may also estimate indicated diesel power. In some embodiments, the control system 11 is configured to estimate the indicated diesel power by multiplying the determined thermal efficiency correction amount by the determined diesel power estimate.

[0048] In some embodiments, determining the diesel power estimate includes using a first lookup table. In various embodiments, the first lookup table is determined or referenced from the diesel ECM and torque fueling calculation module 45. In some embodiments, the first lookup table is based on the diesel fuel rate and the engine speed. In various embodiments, determining the thermal efficiency correction includes referencing a first set of lookup tables. In some embodiments, the first set of lookup tables is determined or referenced from the diesel ECM and torque fueling calculation module 45. In various embodiments, the first set of lookup tables is based on the G / D of the internal combustion engine 20, the MN associated with the internal combustion engine 20, and / or the intake manifold temperature within the internal combustion engine 20. In various embodiments, estimating the first gas power amount includes subtracting the indicated diesel power from the indicated engine power.

[0049] Then, in operation 450, the control system 11 may estimate the second indicated engine power and the second gas power amount. In various embodiments, the second total indicated engine power and the second gas power amount may be based at least in part on the gas LHV value determined in operation 445. In various embodiments, the LHV determined in operation 45 may be based on the first gas power amount (determined in operation 420), the total gas flow estimate, and the thermal efficiency correction amount. In some implementations, the LHV may be determined by an estimate. In various embodiments, the control system 11 may determine the LHV estimate by dividing the first gas power amount by the product of the gas flow estimate and the thermal efficiency correction amount. In various implementations, the resulting LHV is an instantaneous LHV amount. In some embodiments, the control system 11 may be configured to implement a learning algorithm to determine the LHV estimate based on the instantaneous LHV amount.

[0050] In other embodiments, the second total indicated engine power and the second gas power amount may be additionally or alternatively based on the estimated engine gas flow (determined in operation 453) and the estimated diesel power amount (determined in operation 455). In various embodiments, determining the second total indicated engine power includes determining the product of the total gas flow estimate and the LHV estimate, and adding the product of the total gas flow estimate and the LHV estimate to the diesel power estimate. In some embodiments, the control system 11 may be configured to determine the first gas power estimate based on the first total indicated engine power, and determine the second gas power estimate based on the product of the thermal efficiency parameter and the estimated engine gas flow and the LHV estimate. In various embodiments, the thermal efficiency parameter corresponds to the thermal efficiency correction amount. Then, the control system 11 may determine the final gas power estimate based on the first gas power estimate and the second gas power estimate. In various embodiments, the control system 11 may be configured to estimate the G / D of the internal combustion engine 20. In various embodiments, the control system 11 is configured to estimate the G / D of the internal combustion engine 20 by dividing the final gas power estimate by the first total engine power estimate.

[0051] like Figure 5 As shown, in operation 460, the control system 11 may then calculate the difference between the first total indicated engine load (e.g., power, torque, etc.) (determined in operation 420) and the second total indicated engine load (e.g., power, torque, etc.) (determined in operation 450). Then, in operation 465, the control system 11 may compare the difference between the first total indicated engine load (calculated in operation 460) and the second total indicated engine load to a predetermined threshold. For example, in various implementations, the control system 11 may determine the difference between the predetermined threshold and the difference between the first total indicated engine load and the second total indicated engine load (i.e., the total indicated engine load delta). In various embodiments, the predetermined threshold may be set by the OEM and / or user of the dual fuel engine system 10.

[0052] Therefore, if the difference between the total indicated engine load increment and the predetermined threshold is greater than a predetermined amount, the control system 11 can determine that the dual fuel engine system 10 is operating under abnormal or adverse conditions. In various embodiments, the predetermined threshold is associated with a predetermined time period. For example, if the difference between the total indicated engine load increment and the predetermined threshold is greater than a predetermined amount within a predetermined time period, the control system 11 can determine that the dual fuel engine system 10 is operating under abnormal or adverse conditions. Therefore, in response to the control system 11 determining that the difference between the first total indicated engine load and the second total indicated engine load meets the predetermined threshold (or the total indicated engine load increment exceeds the predetermined amount), the control system 11 can activate one or more engine protection measures 470. For example, the control system 11 can disable dual fuel operation, perform a shutdown and / or reduce the engine speed, etc.

[0053] In other embodiments, control system 11 may be configured to determine one or more gas power targets associated with internal combustion engine 20 . Figure 6A method 500 for determining a gas power target associated with an internal combustion engine 20 is shown. The control system 11 measures the engine speed in operation 505 and estimates the amount of engine power in operation 510. In various embodiments, the engine speed is sensed by sensors 95, 35 and / or 40. In some embodiments, the amount of engine power is a net engine power amount. In operation 515, the control system 11 may calculate a percentage of the rated power ("percent power") of the internal combustion engine 20 based on the estimated engine power from operation 510. The percent rated power may be calculated by dividing the net engine power by the rated engine power limit and multiplying by 100%. The control unit may also determine an intake manifold temperature (e.g., a maximum intake manifold temperature) in operation 525 and determine an estimated value of the MN of the gas in operation 530. In operation 520, the control system 11 may determine a base gas substitution rate (G / D) target for the internal combustion engine 20. In various embodiments, the control system 11 determines a base G / D target based on the engine speed, percent rated power, intake manifold temperature (determined in operation 525), and estimated MN of the internal combustion engine 20. Then, in operation 535, the control system 11 determines a gas power target for the internal combustion engine 20 based on the base gas substitution rate target determined in operation 520. In various embodiments, the gas power target is based on the base G / D target and a first indicated engine power estimate. In some embodiments, the controller 11 determines the first indicated engine power estimate by performing operation 420 of method 400. In various embodiments, the first indicated engine power is based on an estimated amount of engine power and an amount of friction power loss.

[0054] In various embodiments, the base G / D target determined in operation 520 is based on a first speed base G / D target when the engine speed is above a threshold (which may be determined in operation 540) and a speed base G / D target when the engine speed is below a threshold (which may be determined in operation 545). In various embodiments, at least one of the first speed base G / D target or the second speed base G / D target is determined based on the intake manifold temperature (determined in operation 525) and / or the estimated methane number (determined in operation 530). In various embodiments, the first speed base G / D target is a high speed base G / D target, and the second speed base G / D target is a low speed base G / D target (i.e., lower than the first base G / D target). In some embodiments, the high speed base G / D target is based on a percentage of rated power, an intake manifold temperature, and an estimated MN value. Similarly, the low speed base G / D target is based on a percentage of rated power, an intake air temperature, and an estimated MN value. Therefore, the base G / D target determined in operation 520 is further determined by interpolation between the high speed base G / D target and the low speed base G / D target based on engine speed. In various embodiments, the high speed base G / D target is determined from a first set of lookup tables and the low speed base G / D target is determined from a second set of lookup tables (i.e., from the lookup tables / database 145).

[0055] In various embodiments, the control system 11 may be configured to operate the dual fuel engine system 10 to determine one or more gas injector commands for at least one engine bank within the internal combustion engine 20 . Figure 7 A method 600 for determining at least one gas injector command for at least one engine bank within the internal combustion engine 20 is shown. In operation 605, the control system 11 is configured to determine a gas flow target. In various implementations, the gas flow target is based on the gas power target determined in operation 625, the thermal efficiency estimate determined in operation 630, and the LHV determined in operation 635. In some implementations, the gas power target determined in operation 625 is determined by the control system 11 via the method 500. In other implementations, the LHV determined in operation 635 is determined via the control system 11 performing one or more operations similar or equivalent to operation 445. In other embodiments, the LHV determined in operation 635 is determined via an LHV sensor or a lookup table based on a measured or estimated MN. In various embodiments, determining the gas flow target in operation 605 includes dividing the gas power target by the thermal efficiency estimate and the LHV.

[0056] The control system 11 is configured to adjust the gas flow target in operation 610 based on at least one of the measured gas temperature determined in operation 640 and / or the gas injector pressure measured in operation 645. In various embodiments, at least one of the gas temperature or the gas injector pressure is measured by the sensor 35, 40, and / or 95. Using the adjusted gas flow target determined in operation 610, the control system 11 is configured to determine at least one basic gas injector command in operation 615. In various embodiments, the at least one basic gas injector command is also determined based on the estimated G / D of the internal combustion engine 20 determined in operation 650 and the G / D target determined in operation 655. In various implementations, the G / D target determined in operation 655 is determined by the controller 11 by implementing one or more operations similar or equivalent to operation 520. Then, in operation 620, the control system 11 may determine at least one gas injector command for at least one engine bank of the internal combustion engine 20. In some embodiments, the gas power target is based on the first indicated engine power estimate and the G / D target. In various implementations, the first indicated engine power estimate is determined by the controller 11 by performing operation 420. In some implementations, adjusting the gas flow target in operation 610 includes calculating an adjusted gas flow target amount. In various embodiments, the gas flow target amount is based on a product of the gas flow target and at least one of: a first ratio of a measured gas temperature to a temperature reference amount, or a second ratio of a measured gas injector pressure to a pressure reference amount.

[0057] In various implementations, the control system 11 may also be configured to estimate the total gas flow. In various embodiments, the estimated total gas flow is based on the measured gas injector pressure (determined in operation 645), the measured gas temperature (determined in operation 640), and at least one gas injector command for at least one engine group. In some implementations, the at least one gas injector command for at least one engine group includes a left group gas injector command (i.e., for the left group 30) and a right group gas injector command (i.e., for the right group 31). In other implementations, determining the left group gas injector command and determining the right group gas injector command include: biasing the at least one gas injector command for at least one engine group to each of the left group 30 and the right group 31. In various embodiments, biasing the at least one gas injector command for at least one engine group to each of the left group 30 and the right group 31 is based on an exhaust temperature difference associated with each of the left group 30 and the right group 31. In some embodiments, the exhaust temperature difference is measured by sensors 35, 40, and / or 95. In other embodiments, the exhaust temperature difference corresponds to the difference between the exhaust temperature measured at the left bank 30 and the exhaust temperature measured at the right bank 31. Therefore, during operation of the dual engine system 10, the control system 11 can measure the exhaust temperature of the left bank 30, measure the exhaust temperature of the right bank 31, and determine the difference between the exhaust temperature of the left bank 30 and the exhaust temperature of the right bank 31. Then, the control system 11 can add the left bank adjustment amount to at least one gas injector command for at least one engine bank. In various embodiments, the control system 11 adds the left bank adjustment amount to at least one gas injector command to determine a first adjusted basic gas injector command based on the difference between the left bank exhaust temperature and the right bank exhaust temperature. Similarly, the control system 11 can then add the right bank adjustment amount to at least one gas injector command for at least one engine bank. In various embodiments, the control system 11 adds the right bank adjustment amount to at least one gas injector command to determine a second adjusted basic gas injector command based on the difference between the left bank exhaust temperature and the right bank exhaust temperature. The control system 11 may then convert each of the first adjusted base gas injector command and the second adjusted base gas injector command into a left group of gas injector commands and a right group of gas injector commands, respectively.

[0058] In some implementations, determining at least one gas injector command for at least one engine bank in operation 615 includes determining a feedforward input for a G / D PID controller operably coupled to the internal combustion engine 20. In various embodiments, the G / D PID controller is the controller 150. In some embodiments, the feedforward input is based on a lookup table. In various embodiments, the lookup table is determined or referenced from the diesel ECM and torque fueling calculation module 45, the diesel air handling, aftertreatment and fuel system reference determination and control module 60 and / or the indicated engine power and gas power estimation module 115. In various embodiments, the lookup table is based on at least one of: a measured gas injector pressure, a measured gas temperature, or an adjusted gas flow target. In some embodiments, the control system 11 is also configured to determine at least one thermal control valve command. In various embodiments, the at least one thermal control valve command is associated with the heater control valve 195. In some embodiments, the at least one thermal control valve command is based on a measured gas temperature and / or a measured gas mass flow rate within the internal combustion engine 20. In yet other embodiments, the control system 11 is further configured to adjust at least one gas temperature set point based on the measured MN and / or the estimated MN number. In various embodiments, the measured MN is measured by sensors 35, 40, and / or 95. In some embodiments, the estimated MN number is determined by the MN estimation module 125. In some implementations, at least one gas temperature set point is based on an engine protection set point. In various embodiments, the engine protection set point is determined or set by the OEM system 12, the diesel control system 14, or the gas control system 16.

[0059] Figure 8A method 700 performed by the dual fuel engine system 10 is shown. In various embodiments, the dual fuel engine system 10 includes at least one PID controller coupled to the internal combustion engine 20 and the gas injector 28. In operation 705, the control system 11 determines a G / D estimate. In various embodiments, the G / D estimate is determined from the LHV and G / D estimation module 120. Then, the control system 11 determines a G / D target in operation 710. In various embodiments, in operation 710, the control system 11 determines the G / D target by performing one or more operations similar or equivalent to operation 520 in method 500. In operation 715, at least one PID controller is configured to receive feedforward input in addition to the G / D estimate and the G / D target. In various embodiments, the feedforward input is based on a lookup table, which can be determined or referenced from the following items: the diesel ECM and torque fueling calculation module 45, the diesel air handling, aftertreatment and fuel system reference determination and control module 60 and / or the indicated engine power and gas power estimation module 115. In some embodiments, the G / D target is determined from the LHV and G / D estimation module 120. In operation 720, at least one PID controller is configured to output at least one gas injector command. In operation 725, at least one PID controller then biases at least one gas injector command to each of the left group 30 and the right group 31. In various embodiments, at least one PID controller biases at least one gas injector command to each of the left group 30 and the right group 31 based on the difference between each of the left group exhaust temperature (determined in operation 730) and the right group exhaust temperature (determined in operation 735). In various embodiments, the exhaust temperature difference is determined in operation 740. In some embodiments, at least one PID controller includes a first PID controller and a second PID controller. For example, the first PID controller can be configured to receive a feedforward input, a G / D estimate, and a G / D target (ie, the PID controller 150), and the second PID controller can be configured to bias at least one gas injector command to each of the left group 30 and the right group 31 (ie, the group balancing PID 155).

[0060] In some embodiments, the dual fuel engine system 10 includes an aftertreatment system operably coupled to the internal combustion engine 20 (i.e., controlled by the aftertreatment control system 85), a gas injection system including at least one gas injector 28 (i.e., controlled by the gas injector control module 110), and an air handling system operably coupled to the internal combustion engine 20 (i.e., controlled by the air handling control system 80). In some implementations, the aftertreatment system is a selective catalytic reduction (SCR) and oxidation catalyst (OC) system. In some embodiments, the gas injection system is configured to independently control the gas injection on each of the left bank 30 and the right bank 31 (i.e., via at least one gas injector 28). In other embodiments, the air handling system is configured to control the air flow through the internal combustion engine 20. In some embodiments, the air handling system controls the air flow independently of the operating conditions of the internal combustion engine 20. In other embodiments, the air flow is based on a predetermined value obtained from a lookup table. In various embodiments, the lookup table is determined by or corresponds to a database 75 in the module 60. In various embodiments, the predetermined value is associated with a target temperature in at least one position of the aftertreatment system.

[0061] In various embodiments, the dual fuel engine system 10 includes one or more heaters operably coupled to at least one gas injector 28 and the internal combustion engine 20. The at least one heater is configured to adjust the temperature of the gas flowing within the internal combustion engine 20 (ie, heat). Fig. 9A method 800 for controlling an operating state of a heater coupled to an internal combustion engine 20 is shown. In operation 805, the control system 11 is configured to determine a gas flow target. For example, the control system 11 is configured to determine the gas flow target via one or more operations similar or equivalent to operation 605. In various implementations, the gas flow target determined in operation 805 may be based on one or more of a gas power target, an estimated thermal efficiency, and an LHV. For example, the gas flow target may be based on the gas power target determined in operation 820, the estimated thermal efficiency of the internal combustion engine 20 determined in operation 825, and the LHV determined in operation 830. In operation 810, the control system 11 may adjust the gas flow target based on at least one of a measured gas temperature or a measured gas injector pressure. For example, in operation 810, the control system 11 is configured to adjust the gas flow target based on at least one of a measured gas temperature determined in operation 835 or a measured gas injector pressure determined in operation 840. In various implementations, the measured gas temperature determined in operation 835 is determined by the control system 11 by performing one or more operations similar or equivalent to operation 640. In some embodiments, the measured gas temperature is determined via sensors 35, 40, and / or 95. In various embodiments, the measured gas injector pressure determined in operation 840 is determined by the control system 11 by performing one or more operations similar or equivalent to operation 645. In some embodiments, the measured gas injector pressure is determined via sensors 35, 40, and / or 95. The control system 11 may then control the operating state of the heater 32 based on at least one of the measured gas temperature or the measured engine coolant temperature. In some embodiments, at least one of the measured gas temperature or the measured engine coolant temperature is determined via sensors 35, 40, and / or 95.

[0062] In some embodiments, the control system 11 is configured to perform on / off control of the heater 32 in response to a determination made about the measured gas temperature relative to one or more threshold temperatures. For example, the control system 11 is configured to control the operation of the heater 32 in response to determining that the measured gas temperature is less than a first threshold temperature for a first period of time. Specifically, in some embodiments, the control system 11 is configured to operate (i.e., turn on) the heater 32 in response to determining that the measured gas temperature (determined in operation 835) is less than a first threshold temperature for a first period of time. In various embodiments, the first threshold temperature is set by the OEM system 12, the diesel control system 14, or the gas control system 16. In other embodiments, the control system 11 is configured to control the operation of the heater 32 in response to determining that the measured gas temperature is greater than a second threshold temperature for a second period of time. For example, the control system 11 is configured to operate (i.e., turn off) the heater 32 in response to determining that the measured gas temperature (determined in operation 835) is greater than a second threshold temperature for a second period of time. In various embodiments, the second threshold temperature is set by the OEM system 12, the diesel control system 14, or the gas control system 16.

[0063] Although the above reference Figure 1-Figure 9 Embodiments are described, but various modifications and inclusions to those embodiments are contemplated and considered to be within the scope of the present disclosure.

[0064] The present technology may also include, but is not limited to, the features and combinations of features described in the following lettered paragraphs, and it should be understood that the following paragraphs should not be interpreted as limiting the scope of the appended claims or requiring that all such features must be included in these claims:

[0065] A. A method for controlling a dual fuel engine system, the method comprising:

[0066] estimating a total indicated engine load based on a sum of measured engine power and a power loss estimate; and

[0067] determining a total fueling amount based on the engine speed and the total indicated engine load, the total fueling amount including a gaseous fueling amount and a diesel fueling amount; and

[0068] The total fueling amount is used to control the dual fuel engine system.

[0069] B. The method of paragraph A, wherein the method further comprises determining a first updated total fuel fill based on a maximum value between the total fuel fill and a first diesel fuel command.

[0070] C. A method according to paragraph B, wherein the method also includes determining a second updated total fuel fill amount, and wherein determining the second updated total fuel fill amount includes: subtracting the first diesel fuel command from the first updated total fuel fill amount to determine the diesel fuel equivalent of the gaseous fuel fill amount; and adding the diesel fuel equivalent of the gaseous fuel fill amount to the second diesel fuel command.

[0071] D. The method of paragraph A, wherein controlling the dual fuel engine system includes determining a diesel fuel system actuator command.

[0072] E. The method of paragraph A, wherein determining the total fueling amount includes referencing a torque-fuel lookup table based on the engine speed and an indicated diesel torque input.

[0073] F. The method of paragraph A, wherein the method further comprises determining the power loss estimate based on a friction torque estimate, an accessory torque estimate, a charge air pumping torque, and the engine speed.

[0074] G. The method according to paragraph F, wherein the method further comprises:

[0075] determining the friction torque estimate from a second lookup table, the second lookup table being based on the engine speed and an engine friction parameter;

[0076] Wherein the engine friction parameter is based on at least one of an oil temperature or a coolant temperature within the dual fuel engine system.

[0077] H. A method as described in paragraph E, wherein the method further comprises determining the accessory torque estimate from a third lookup table, the third lookup table being based on the engine speed and an accessory torque parameter.

[0078] I. The method of paragraph H, wherein the method further comprises determining the accessory torque parameter based on a cooling fan power or duty cycle commanded by the dual fuel engine system.

[0079] J. The method of paragraph B, wherein the method further comprises determining at least one actuator command based on at least one of the first updated total fueling amount or the second updated total fueling amount and the engine speed.

[0080] K. A method according to paragraph A, wherein the method also includes determining the first diesel fuel command from a torque-fuel lookup table, wherein the torque-fuel lookup table is based on the sum of the friction power estimate and the torque demand and the engine speed, and the torque demand is set by an engine speed governor within the dual-fuel engine system.

[0081] L. A method for controlling a dual fuel engine system, the method comprising:

[0082] estimating a total indicated engine load based on a sum of the measured engine power, the friction power estimate, and the accessory power estimate;

[0083] determining a total fueling amount from a first lookup table, the lookup table being based on engine speed and the total indicated engine load;

[0084] determining at least one updated total fuel fill based on the total fuel fill and an operational state of a dual fuel mode switch within the dual fuel engine system; and

[0085] determining a control input for at least one actuator within the dual fuel engine system;

[0086] Wherein the control input is based on selecting a corresponding set of lookup tables associated with the at least one actuator, the set of lookup tables comprising a plurality of lookup tables, each of the plurality of lookup tables being based on the engine speed and the at least one updated total fueling amount.

[0087] M. The method of paragraph L, wherein the at least one actuator is at least one of: an air handling actuator, an aftertreatment actuator, or a diesel fuel system actuator.

[0088] N. The method of paragraph L, wherein selecting the corresponding set of lookup tables includes determining a compressor inlet density, a gas substitution rate within the dual engine system, and the operating state of the dual fuel mode switch.

[0089] O. The method of paragraph N, wherein selecting the set of lookup tables further comprises selecting at least one of: an air handling reference table, an aftertreatment reference table, or a fueling reference table.

[0090] P. A method according to paragraph O, wherein the at least one updated fueling amount includes a first updated fueling amount and a second updated fueling amount, wherein the first updated fueling amount corresponds to a maximum value between the total fueling amount and a diesel fuel command, and wherein the second updated fueling amount is determined by subtracting the diesel fuel command from the first updated total fueling amount to determine a diesel fuel equivalent of the gaseous fueling amount, and adding the diesel equivalent fueling amount to the second diesel fuel command.

[0091] Q. A dual fuel engine system comprising:

[0092] an internal combustion engine operable in a dual fuel mode;

[0093] at least one actuator operably coupled to the internal combustion engine; and

[0094] at least one controller in communication with the internal combustion engine and the at least one actuator;

[0095] Wherein, the at least one controller is configured to:

[0096] receiving a first input corresponding to engine speed and a second input corresponding to measured engine power;

[0097] Calculate power loss estimates;

[0098] determining a total fueling amount based on the measured engine power and the power loss estimate;

[0099] determining a first diesel fuel command associated with the internal combustion engine based at least on the calculated governor command and the power loss estimate;

[0100] determining at least one updated total fueling amount based on the total fueling amount and the first diesel fuel command;

[0101] selecting a set of lookup tables associated with the at least one actuator based on a gas substitution rate associated with the internal combustion engine, the set of lookup tables being based on the engine speed and the at least one updated total fueling amount; and

[0102] An input is sent to the at least one actuator based on the set of lookup tables.

[0103] R. A system as described in paragraph Q, wherein the at least one controller is further configured to determine an indicated diesel torque input based on a sum of the friction power estimate and an engine speed torque demand, wherein the engine speed torque demand corresponds to a difference between the engine speed and an engine speed target.

[0104] S. The system of paragraph Q, wherein the at least one controller is configured to determine the power loss estimate based on a friction torque estimate, an accessory torque estimate, a charge air pumping torque, and the engine speed.

[0105] T. The system of paragraph Q, wherein the at least one controller is further configured to select the lookup table based on compressor inlet density.

[0106] U. A method for controlling a dual fuel engine system, the method comprising:

[0107] determining an amount of friction power loss of an internal combustion engine of the dual fuel engine system, the amount of friction power loss being based on an engine speed and a friction torque estimate of the internal combustion engine;

[0108] determining an amount of accessory power loss of power of the internal combustion engine, the amount of accessory power loss being based on the engine speed and an estimate of accessory torque;

[0109] estimating a net engine power amount based on the accessory power loss amount and a brake power amount of the internal combustion engine;

[0110] Estimated indicated diesel power; and

[0111] A first indicated engine power and a first gas power are estimated based on the estimated net engine power.

[0112] V. The method of paragraph U, wherein estimating the indicated diesel power comprises multiplying the determined thermal efficiency correction by the determined diesel power estimate.

[0113] W. The method of paragraph V, wherein determining the diesel power estimate includes using a first lookup table based on a diesel fuel rate and the engine speed.

[0114] X. The method of paragraph V, wherein determining the thermal efficiency correction includes consulting a first set of lookup tables, the first set of lookup tables being based on at least one of a gas substitution rate, a methane number, or an intake manifold temperature.

[0115] Y. The method of paragraph V, wherein the method further comprises determining a gas lower heating value (LHV) estimate based on the first gas power, the total gas flow estimate, and the thermal efficiency correction.

[0116] Z. The method of paragraph Y, wherein determining the LHV estimate comprises dividing the first gas power by the product of the gas flow estimate and the thermal efficiency correction to determine an instantaneous LHV amount.

[0117] AA. The method of paragraph Z, wherein the method further comprises applying a learning algorithm to the instantaneous LHV amount to determine the LHV estimate.

[0118] BB. The method of paragraph Z, wherein the method further comprises estimating a second total indicated engine power, wherein estimating the second total indicated engine power comprises:

[0119] determining a product of the total gas flow estimate and the LHV estimate; and

[0120] A sum of the product of the total gas flow and the LHV estimate and the diesel power estimate is determined.

[0121] CC. The method of paragraph BB, wherein the method further comprises determining a difference between the first total indicated engine power and the second total indicated engine power.

[0122] DD. The method of paragraph CC, wherein the method further comprises activating at least one engine protection measure based on a difference between the first indicated total engine power and the second indicated total engine power being greater than a threshold.

[0123] EE. The method of paragraph DD, wherein the threshold is associated with a predetermined time period.

[0124] FF. The method of paragraph V, wherein estimating the first gas power comprises subtracting the indicated diesel power from the indicated engine power.

[0125] GG. A method for controlling a dual-fuel engine system, the method comprising:

[0126] estimating a net engine power amount of the internal combustion engine based on an accessory power loss amount of power of an internal combustion engine of the dual fuel engine system and an estimate of brake power of the internal combustion engine;

[0127] determining a first total indicated engine power based on the net engine power and an amount of friction power losses of the internal combustion engine;

[0128] determining a lower heating value (LHV) of gases within the internal combustion engine, the LHV being a measured value or an estimated value;

[0129] estimating a second total indicated engine power based on the LHV, the total gas flow estimate, and the diesel power estimate; and

[0130] At least one engine protection measure is activated based on a difference between the first indicated total engine power and the second indicated total engine power being greater than a predetermined threshold.

[0131] HH. The method of paragraph GG, wherein estimating the second total indicated engine power comprises:

[0132] A sum of the product of the total gas flow and the LHV and the diesel power estimate is determined.

[0133] II. The method according to paragraph GG, wherein the method further comprises:

[0134] determining a first gas power estimate, the first gas power estimate being based on the first total indicated engine power;

[0135] determining a second gas power estimate based on the LHV and a product of a thermal efficiency estimate and the total gas flow estimate; and

[0136] A final gas power estimate is determined based on the first gas power estimate and the second gas power estimate.

[0137] JJ. The method according to paragraph II, wherein the method further comprises estimating a gas replacement rate, wherein estimating the gas replacement rate comprises:

[0138] The final gas power estimate is divided by the first power estimate.

[0139] KK. A dual-fuel engine system operable in a dual-fuel mode, the dual-fuel engine system comprising:

[0140] at least one controller in communication with the internal combustion engine;

[0141] Wherein, the at least one controller is configured to:

[0142] receiving an input corresponding to an engine speed of the internal combustion engine;

[0143] receiving input for calculating a net engine power estimate;

[0144] calculating a percentage of rated power of the internal combustion engine based on the engine speed and the net engine power estimate;

[0145] determining a base gas substitution rate target for the internal combustion engine based on the engine speed, the percentage of rated power, an intake manifold temperature within the internal combustion engine, and an estimated methane number within the internal combustion engine; and

[0146] A gas power target for the internal combustion engine is determined based on the base gas substitution rate target and a first indicated engine power estimate.

[0147] LL. The system of paragraph KK, wherein the controller is configured to determine the base gas substitution rate target by performing the following operations:

[0148] When the engine speed is higher than a threshold, determining a first speed base gas substitution rate target based on the rated power percentage, the intake manifold temperature, and the methane number estimate;

[0149] determining a second speed base gas substitution rate target based on the rated power percentage, the intake manifold temperature, and the methane number estimate when the engine speed is below the threshold; and

[0150] The base gas substitution rate target is determined based on the engine speed, the high speed base gas substitution rate target, and the low speed base gas substitution rate target.

[0151] MM. The system of paragraph LL, wherein the first speed base gas substitution rate target is determined based on a first set of lookup tables, and the second speed base gas substitution rate target is determined based on a second set of lookup tables.

[0152] NN. The system of paragraph KK wherein the first indicated engine power is based on the net engine power estimate and an amount of friction power losses.

[0153] OO. A method for controlling a dual fuel engine system, the method comprising:

[0154] determining a gas flow target for an internal combustion engine of the dual fuel engine system, the gas flow target being based on a gas power target for the internal combustion engine, an estimate of thermal efficiency of the internal combustion engine, and a lower heating value (LHV) within the internal combustion engine;

[0155] adjusting the gas flow target based on at least one of a measured gas temperature or a measured gas injector pressure;

[0156] determining at least one base gas injector command based on the adjusted gas flow target, the gas substitution rate estimate, and the gas substitution rate target; and

[0157] A gas injector command for at least one engine bank is determined based on the at least one base gas injector command.

[0158] PP. The method of paragraph OO, wherein the method further comprises estimating a total gas flow based on the measured gas injector pressure, the measured gas temperature, and the at least one gas injector command for the at least one engine bank.

[0159] QQ. The method of paragraph OO, wherein the at least one engine group includes a left group and a right group, wherein the at least one gas injector command for the at least one engine group includes a left group of gas injector commands and a right group of gas injector commands, and determining the left group of gas injector commands and the right group of gas injector commands includes:

[0160] The at least one gas injector command for the at least one engine bank is biased to each of the right engine bank and the left engine bank based on an exhaust gas temperature difference associated with each of the right engine bank and the left engine bank.

[0161] RR. The method of paragraph QQ, wherein biasing the at least one base gas injector command to each of the engine right bank and the engine left bank comprises:

[0162] Measure the exhaust temperature of the left group;

[0163] Measure the exhaust temperature of the right group;

[0164] determining a difference between the right set of exhaust temperatures and the left set of exhaust temperatures;

[0165] adding a left bank adjustment amount to the at least one gas injector command for the at least one engine bank to determine a first adjusted base gas injector command based on a difference between the right bank exhaust temperature and the left bank exhaust temperature;

[0166] adding a right bank adjustment amount to the at least one gas injector command for the at least one engine bank to determine a second adjusted base gas injector command based on a difference between the right bank exhaust temperature and the left bank exhaust temperature; and

[0167] Each of the first adjusted base gas injector command and the second adjusted base gas injector command is converted into the left group of gas injector commands and the right group of gas injector commands, respectively.

[0168] SS. The method of paragraph OO, wherein determining the gas flow target comprises dividing the gas power target by the thermal efficiency estimate and the LHV.

[0169] TT. The method of paragraph SS, wherein the gas power target is based on a first indicated engine power estimate and the gas substitution rate target.

[0170] UU. The method according to paragraph OO, wherein adjusting the gas flow target comprises:

[0171] An adjusted gas flow target is calculated, the adjusted gas flow target being a product of the gas flow target and at least one of: a first ratio of the measured gas temperature to a temperature reference or a second ratio of the measured pressure to a pressure reference.

[0172] VV. The method of paragraph UU, wherein determining at least one gas injector command for the at least one engine bank comprises:

[0173] A feedforward input for a gas substitution rate proportional-integral-derivative controller operably coupled to the internal combustion engine is determined, the feedforward input being based on a lookup table that references at least one of: the measured gas injector pressure, the measured gas temperature, or the adjusted gas flow target amount.

[0174] WW. The method according to paragraph OO, wherein the method further comprises:

[0175] At least one heater control command is determined based on at least one of the measured gas temperature or the measured gas mass flow rate.

[0176] XX. The method according to paragraph WW, wherein the method further comprises:

[0177] At least one gas temperature set point is adjusted based on at least one of the measured methane number or the estimated methane number.

[0178] YY. The method of paragraph XX, wherein the at least one gas temperature set point is based on an engine protection set point.

[0179] ZZ. A dual-fuel engine system for an internal combustion engine, the dual-fuel engine system comprising:

[0180] at least one gas injector operably coupled to the internal combustion engine, the internal combustion engine having a left bank and a right bank, the internal combustion engine being operable in a dual fuel mode; and

[0181] at least one proportional-integral-derivative (PID) controller communicatively coupled to the internal combustion engine and the at least one gas injector;

[0182] Wherein, the at least one PID controller is configured as:

[0183] receiving a feedforward input, a gas replacement rate estimate, and a gas replacement rate target;

[0184] outputting at least one gas injector command based on the feedforward input; and

[0185] The at least one gas injector command is biased to each of the right and left groups based on an exhaust temperature difference associated with each of the right and left groups.

[0186] AAA. The system of paragraph ZZ, wherein the at least one PID controller is configured to bias the at least one gas injector command to each of the right group and the left group by performing operations comprising:

[0187] Measure the exhaust temperature of the left group;

[0188] Measure the exhaust temperature of the right group;

[0189] determining a difference between the right set of exhaust temperatures and the left set of exhaust temperatures;

[0190] adding a left set of adjustment amounts to the at least one gas injector command to determine a first adjusted gas injector command;

[0191] adding a right set of adjustment amounts to the at least one gas injector command to determine a second adjusted gas injector command; and

[0192] Each of the first adjusted gas injector command and the second adjusted gas injector command is converted into a left set of gas injector commands and a right set of gas injector commands, respectively.

[0193] BBB. A system according to paragraph ZZ, wherein the at least one PID controller includes a first PID controller and a second PID controller, wherein the first PID controller is configured to receive the feedforward input, the gas substitution rate estimate, and the gas substitution rate target, and wherein the second PID controller is configured to bias the at least one gas injector command to each of the right group and the left group.

[0194] CCC. A system according to paragraph ZZ, wherein the system further comprises:

[0195] an aftertreatment system operably coupled to the internal combustion engine, the aftertreatment system being a selective catalytic reduction (SCR) and oxidation catalyst (OC) system;

[0196] a gas injection system operably coupled to the internal combustion engine, the gas injection system comprising the at least one gas injector, wherein the gas injection system is configured to independently control the injection of gas on each of the left and right groups; and

[0197] An air handling system operably coupled to the internal combustion engine, the air handling system configured to control air flow through the internal combustion engine independent of operating conditions of the internal combustion engine, wherein the air flow is based on a predetermined value obtained from a lookup table, the predetermined value being associated with a target temperature in at least one location of the aftertreatment system.

[0198] DDD. A dual fuel engine system operable in a dual fuel mode, the dual fuel engine system comprising:

[0199] an internal combustion engine having at least one engine block;

[0200] at least one gas injector operably coupled to the internal combustion engine; and

[0201] at least one controller communicatively coupled to the internal combustion engine and the at least one gas injector;

[0202] Wherein, the at least one controller is configured to:

[0203] determining a gas flow target for the internal combustion engine, the gas flow target being based on a gas power target for the internal combustion engine, an estimate of thermal efficiency of the internal combustion engine, and a lower heating value (LHV) within the internal combustion engine;

[0204] adjusting the gas flow target based on at least one of a measured gas temperature or a measured gas injector pressure to determine an adjusted gas flow target for the dual fuel mode;

[0205] determining at least one base gas injector command based on the adjusted gas flow target, the gas substitution rate estimate, and the gas substitution rate target; and

[0206] A gaseous injector command for the at least one engine bank is determined based on the at least one base injector command.

[0207] EEE. The system of paragraph DDD, wherein the system further comprises:

[0208] at least one heater operably coupled to the internal combustion engine, the at least one controller, and the at least one gas injector; and

[0209] Wherein, the at least one controller is further configured to:

[0210] controlling an operating state of the at least one heater based on the measured gas temperature and engine coolant temperature; and

[0211] The at least one heater is operated in response to determining that the measured gas temperature is less than a first threshold temperature for a first time period.

[0212] FFF. The system of paragraph EEE, wherein the at least one controller is configured to control the at least one heater to shut off in response to determining that the measured gas temperature is greater than a second threshold temperature for a second time period.

[0213] GGG. The system of paragraph DDD, wherein the at least one controller is further configured to:

[0214] A left set of gas injector commands and a right set of gas injector commands are determined based on the at least one gas injector command.

[0215] HHH. A system as described in paragraph GGG, wherein the at least one controller is further configured to determine the gas flow target by dividing the gas power target by a thermal efficiency estimate and a lower heating value (LHV), wherein the LHV is determined from a lookup table based on an estimated methane number.

[0216] It should be noted that the term "exemplary" and variations thereof as used herein to describe various embodiments are intended to indicate that these embodiments are possible examples, representations, or illustrations of possible embodiments (and these terms are not intended to imply that these embodiments are necessarily the most specific or superlative examples).

[0217] As used herein, the term "coupled" and variations thereof refer to two components being directly or indirectly joined to one another. Such joining may be stationary (e.g., permanent or fixed) or movable (e.g., removable or releasable). Such joining may be achieved using two components that are directly coupled to one another, wherein the two components are coupled to one another using a separate intermediate component and any additional intermediate components that are coupled to one another, or wherein the two components are coupled to one another using an intermediate component that is integrally formed with one of the two components as a single entity. If "coupled" or variations thereof are modified by additional terms (e.g., directly coupled), the general definition of "coupled" provided above is modified by the plain language meaning of the additional terms (e.g., "directly coupled" means the joining of two components without any separate intermediate components), resulting in a narrower definition than the general definition of "coupled" provided above. Such coupling may be mechanical, electrical, or fluidic.

[0218] References to element positions herein (e.g., "top," "bottom," "above," "below") are only used to describe the orientation of various elements in the drawings. It should be noted that according to other exemplary embodiments, the orientation of various elements may be different, and such variations are intended to be included in the present disclosure.

[0219] In some embodiments, hardware and data processing components for implementing various processes, operations, illustrative logic, logic blocks, modules, and circuits described in conjunction with the embodiments disclosed herein, such as hardware and data processing components of a controller (e.g., memory within the controller 18, memory within the OEM system 12, memory within the diesel control system 14, or memory within the gas control system 16), can be implemented or executed using a general purpose single-chip or multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration. In some embodiments, specific processes and methods may be performed by circuits specific to a given function. Memory (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 to accomplish or facilitate the various processes, layers, and modules described in the present disclosure. Memory may be or may include volatile memory or non-volatile memory, and 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 in the present disclosure. According to an exemplary embodiment, memory (e.g., memory within controller 18, memory within OEM system 12, memory within diesel control system 14, or memory within gas control system 16) is communicatively connected to a processor via processing circuitry and includes computer code for executing (e.g., by processing circuitry or a processor) one or more processes described herein.

[0220] The present disclosure contemplates methods and systems for implementing various operations (e.g., such as the operations 305-360 of method 300, the operations 405-470 of method 400, the operations 505-545 of method 500, the operations 605-655 of method 600, the operations 705-740 of method 700, and the operations 805-845 of method 800) on any machine-readable medium. An embodiment of the present disclosure may be implemented using an existing computer processor, or by a dedicated computer processor of an appropriate system introduced for this purpose or another purpose, or by a hard-wired system. Embodiments within the scope of the present disclosure include program products, which include machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. Such machine-readable media may be any available medium, which may be accessed by a general or special-purpose computer or other machine with a processor. For example, such machine-readable media may include RAM, ROM, EPROM, EEPROM or other optical disk storage, magnetic disk storage or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of machine-executable instructions or data structures and can be accessed by a general or special-purpose computer or other machine with a processor. The above combinations are also included in the scope of machine-readable media. Machine-executable instructions include, for example, instructions and data that cause a general-purpose computer, a special-purpose computer, or a special-purpose processing machine to perform a function or a group of functions.

[0221] Although the drawings and the specification may show a specific order of method steps, the order of these steps may be different from that depicted and described, unless otherwise specified above. In addition, two or more steps may be performed simultaneously or partially simultaneously, unless otherwise specified above.

[0222] It is important to note that any element disclosed in one embodiment may be combined or used with any other embodiment disclosed herein. Although only one example of an element from one embodiment that may be combined or utilized in another embodiment is described above, it should be understood that other elements of the various embodiments may be combined or used with any other embodiment disclosed herein.

Claims

1. A method for controlling a dual fuel engine system, the method include: estimating a total indicated engine load based on a sum of measured engine power and a power loss estimate; determining a total fueling amount based on the engine speed and the total indicated engine load, the total fueling amount including a gaseous fueling amount and a diesel fueling amount; and The total fueling amount is used to control the dual fuel engine system. 2 . The method of claim 1 , further comprising determining a first updated total fueling amount based on a maximum value between the total fueling amount and a first diesel fuel command.

3. The method of claim 2 further comprising determining a second updated total fuel fill amount, in, Determining the second updated total fueling amount includes: subtracting the first diesel fuel command from the first updated total fueling amount to determine a diesel fuel equivalent of the gaseous fueling amount; and The diesel fuel equivalent of the gaseous fuel fill amount is added to a second diesel fuel command.

4. The method according to claim 1, in, Controlling the dual fuel engine system includes determining diesel fuel system actuator commands.

5. The method according to claim 1, in, Determining the total fueling amount includes referencing a torque-fuel lookup table based on the engine speed and an indicated diesel torque input. 6 . The method of claim 1 , further comprising determining the power loss estimate based on a friction torque estimate, an accessory torque estimate, a charge air pumping torque, and the engine speed.

7. The method according to claim 6, further comprising: include: determining the friction torque estimate from a second lookup table, the second lookup table being based on the engine speed and an engine friction parameter; Wherein the engine friction parameter is based on at least one of an oil temperature or a coolant temperature within the dual fuel engine system. 8 . The method of claim 5 , further comprising determining the accessory torque estimate from a third lookup table, the third lookup table being based on the engine speed and an accessory torque parameter. 9 . The method of claim 8 , further comprising determining the accessory torque parameter based on a cooling fan power or duty cycle commanded by the dual fuel engine system.

10. The method of claim 2, further comprising determining at least one actuator command based on at least one of the first updated total fueling amount or the second updated total fueling amount and the engine speed.

11. The method of claim 1 further comprising determining the first diesel fuel command from a torque-fuel lookup table based on a sum of a friction power estimate and a torque demand set by an engine governor within the dual fuel engine system and the engine speed.

12. A method for controlling a dual fuel engine system, the method include: estimating a total indicated engine load based on a sum of the measured engine power, the friction power estimate, and the accessory power estimate; determining a total fueling amount from a first lookup table, the lookup table being based on engine speed and the total indicated engine load; determining at least one updated total fuel fill amount based on the total fuel fill amount and an operational state of a dual fuel mode switch within the dual fuel engine system; and determining a control input for at least one actuator within the dual fuel engine system; Wherein the control input is based on selecting a corresponding set of lookup tables associated with the at least one actuator, the set of lookup tables comprising a plurality of lookup tables, each of the plurality of lookup tables being based on the engine speed and the at least one updated total fueling amount.

13. The method according to claim 12, in, The at least one actuator is at least one of: an air handling actuator, an aftertreatment actuator, or a diesel fuel system actuator.

14. The method according to claim 12, in, Selecting the corresponding set of lookup tables includes determining a compressor inlet density, a gas substitution rate within the dual engine system, and the operating state of the dual fuel mode switch.

15. The method according to claim 14, in, Selecting the set of lookup tables further includes selecting at least one of: an air handling reference table, an aftertreatment reference table, or a fueling reference table.

16. The method according to claim 15, in, The at least one updated fueling amount includes a first updated fueling amount and a second updated fueling amount, wherein the first updated fueling amount corresponds to a maximum value between the total fueling amount and a diesel fuel command, and wherein the second updated fueling amount is determined by subtracting the diesel fuel command from the first updated total fueling amount to determine a diesel fuel equivalent of the gaseous fuel fill, and adding the diesel equivalent fueling amount to the second diesel fuel command.

17. A dual fuel engine system, include: an internal combustion engine capable of operating in a dual fuel mode; at least one actuator operably coupled to the internal combustion engine; and at least one controller in communication with the internal combustion engine and the at least one actuator; Wherein, the at least one controller is configured to: receiving a first input corresponding to engine speed and a second input corresponding to measured engine power; Calculate power loss estimates; determining a total fueling amount based on the measured engine power and the power loss estimate; determining a first diesel fuel command associated with the internal combustion engine based at least on the calculated governor command and the power loss estimate; determining at least one updated total fueling amount based on the total fueling amount and the first diesel fuel command; selecting a set of lookup tables associated with the at least one actuator based on a gas replacement rate associated with the internal combustion engine, the set of lookup tables being based on the engine speed and the at least one updated total fueling amount; and An input is sent to the at least one actuator based on the set of lookup tables.

18. The system according to claim 17, in, The at least one controller is further configured to determine a commanded diesel torque input based on a sum of the friction power estimate and an engine speed torque request corresponding to a difference between the engine speed and an engine speed target.

19. The system according to claim 17, in, The at least one controller is configured to determine the power loss estimate based on a friction torque estimate, an accessory torque estimate, a charge air pumping torque, and the engine speed.

20. The system according to claim 17, in, The at least one controller is further configured to select the lookup table based on a compressor inlet density.

Images