Lambda control strategy for hydrogen fueled internal combustion engines

Abstract

A lambda control strategy for a lean burn internal combustion engine employs a charge air adjustment following a lambda-based fuel adjustment process with closed loop control to adjust the final fueling command to meet transient lambda limits. A NOx output high spike value during transient conditions is determined via a regression model and provides an input relating to the aftertreatment system for closed loop control.

Description

Atty Docket No CMI002-00179 / 24-0030-SRCLAMBDA CONTROL STRATEGY FOR HYDROGEN FUELED INTERNALCOMBUSTION ENGINESCross-Reference to Related Application;

[0001] The present application claims priority to Chinese Patent Application No. 202411156674.0 filed on August 22, 2024, which is incorporated herein by reference.Field of the Invention:

[0002] The present application is related to internal combustion engines, and more particularly to a lambda control strategy for hydrogen fueled internal combustion engines.BACKGROUND

[0003] For hydrogen fueled internal combustion engines, a lean bum strategy is used to control knock boundaries and provide a higher brake thermal energy (BTE) target. During transient responses of the engine, the lambda reduces quickly to a rich bum area. This transient response increases fueling to meeting the output demand for the engine, but also increases the risk for knock and for higher engine out nitrogen oxides (NOx). Current techniques for controlling the fueling of lean bum combustion engines suffer from various shortcomings with respect to transient response, meeting BTE targets, and mitigating knock and NOx. Therefore, further improvements in this technological area are needed.Atty Docket No CMI002-00179 / 24-0030-SRCSUMMARY

[0004] The present application includes systems, methods, and apparatuses that determine a lambda control strategy in response to one or more engine operating parameters while a lean burn spark ignited internal combustion engine is operating. The lambda control strategy employs a process in which the charge flow adjustment follows the lambda-based fuel adjustment. The lambda-based fuel adjustment employs a closed-loop control strategy, including both feedforward control and feedback control adjustments to determine the final fueling command while meeting transient lambda limits. In an embodiment, an estimate for a NOx output high spike value during transient conditions is determined via a regression model and provides an input for the NOx reduction control for the aftertreatment system. The disclosed lambda and NOx control strategy allows for flexible and precise lambda control for lean-bum combustion while balancing transient response, knock, brake thermal energy, and NOx emission control requirements.

[0005] This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings.Atty Docket No CMI002-00179 / 24-0030-SRCBRIEF DESCRIPTION OF THE DRAWINGS

[0006] The description herein makes reference to the accompanying figures wherein like reference numerals refer to like parts throughout the several views.

[0007] FIG. 1 illustrates a schematic block diagram of an exemplary internal combustion engine system that includes a lean bum spark ignition internal combustion engine.

[0008] FIG. 2 illustrates a schematic diagram of an exemplary lambda control circuit configured to control fueling of the engine system of FIG. 1.

[0009] FIG. 3 illustrates a schematic diagram of an exemplary charge flow control circuit configured to determine air handling actuator commands to provide a charge flow to the engine in response to the lambda control strategy of FIG. 2.

[0010] FIGs. 4A-4B illustrate a process flow diagram for a lambda control strategy including charge flow control and thermal management control for the aftertreatment system for the engine system of FIG. 1 .

[0011] FIG. 5 illustrates a flow diagram of an exemplary lambda control circuit with spark timing, injection timing, and fuel rail pressure control circuits.

[0012] The foregoing summary, as well as the following detailed description of certain embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings, certain embodiments. It should be understood, however, that the present invention is not limited to the arrangements and instrumentalities shown in the attached drawings. Further, like numbers in the respective figures indicate like or comparable parts.Atty Docket No CMI002-00179 / 24-0030-SRCDESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0013] Certain terminology is used in the foregoing description for convenience and is not intended to be limiting. Words such as “upper,” “lower,” “top,” “bottom,” “first,” and “second” designate directions in the drawings to which reference is made. This terminology includes the words specifically noted above, derivatives thereof, and words of similar import. Additionally, the words “a” and “one” are defined as including one or more of the referenced item unless specifically noted. The phrase “at least one of’ followed by a list of two or more items, such as “A, B or C,” means any individual one of A, B or C, as well as any combination thereof.

[0014] Embodiments of the present application include a lambda control strategy and method that can improve lean bum spark ignited internal combustion engine performance using gaseous hydrogen fuel to better respond to transient conditions while providing NOx mitigation. A nominal or base fuel quantity is determined from torque to fuel tables. The base fuel quantity and the charge flow are used to determine a base fuel lambda target to which lambda limits are applied to determine a control lambda output. Closed-loop control is used to correct the control lambda output, and the corrected control lambda output is used along with the charge flow to determine a fuel quantity for the final fuel command to fuel the engine. As used herein, lambda is the air-fuel ratio (AFR) value divided by the stochiometric air-fuel ratio (AFRstoich) for a gaseous fuel such as hydrogen fuel.

[0015] In an embodiment, the closed-loop control includes feedforward control based on the control lambda output and feedback control based on a sensed lambda during operation of the internal combustion engine. Embodiments further include determining one or more charge flow commands for intake air to the engine based on the base fuel quantity. Embodiments further include estimating a NOx output high spike value from the engine during transient conditions. Embodiments further include determining spark timing, end-of-inj ection timing, and / or fuel rail pressure commands.

[0016] FIG. 1 illustrates a schematic block diagram of an exemplary internal combustion engine system 100 that includes a lean burn spark ignition internal combustion engine 102 that is connected to an intake 104 and an exhaust 106. It shall be appreciated that the illustrated configuration and components of the engine system 100 are but one example, and that the disclosure contemplates that a variety of different engine systems and the associated components may be utilized. Further, the engine system 100 may be used in a variety of different applicationsAtty Docket No CMI002-00179 / 24-0030-SRC or platforms, and moreover with a variety of different types of machines, vehicles, and / or devices, including, but not limited to, stationary devices as well as on-road vehicles, including automotive applications.

[0017] Engine 102 can receive fuel from one or more fuel sources 108 that include gaseous hydrogen fuel. Further, while the illustrated embodiment may generally depict an engine system 100 used with lean bum spark ignition engine applications powered by gaseous hydrogen fuel, the engine system 100 can be structured to operate with a variety of types of fuels that are delivered from the fuel source 108, including, for example, gaseous fuels such as hydrogen, natural gas, biogas, methane, propane, gasoline, ethanol, producer gas, field gas, liquefied natural gas, compressed natural gas, landfill gas, gaseous fuel, and / or any combination thereof, among other fuels.

[0018] According to the exemplary embodiment, the engine 102 includes an engine block that may define at least a portion of one or more cylinders 110. For example, according to certain embodiments, the engine 102 can include six cylinders 110 in an in-line arrangement as illustrated in FIG. 1. However, the engine 102 may have any different number of cylinders 110, as well as cylinders in a variety of different arrangements. Additionally, each cylinder 110 is sized to accommodate the slideable displacement of a piston (not shown) along at least a portion of the cylinder 110 such that the pistons may reciprocate between a top-dead-center position and a bottom-dead-center position. Each of the cylinders 110, its respective piston and cylinder head, form a combustion chamber. Further, at least a portion of the forces generated by the slideable displacement of the piston along at least a portion of the cylinder during combustion events in the combustion chamber are transmitted to a mechanical drive system (not shown.) For example, the pistons are typically operably coupled to a crank shaft of the engine system 100 that converts the reciprocal movement of the pistons of the engine 102 into rotational movement.

[0019] The cylinders 110 are in selective fluid communication with the intake 104 such that a charge flow of intake air, also known as an intake air flow and / or mass air flow (MAF), can be delivered to the combustion chamber in an amount controlled by intake throttle 106. The cylinders 110 are also in selective fluid communication with the exhaust 106 such that exhaust gases produced by combustion of fuel(s) in the combustion chambers can be delivered through an exhaust manifold 112 of the exhaust 106. The exhaust 106 can include and / or be coupled to a variety of different components, such as, for example, one or more turbines 114a of turbocharger 114, as well as an aftertreatment system 116. The charge flow to engine 102 can also be controlledAtty Docket No CMI002-00179 / 24-0030-SRC with an exhaust actuator, such as wastegate 107. Engine system 100 may also include an exhaust gas recirculation system (not shown), such as a high pressure and / or a low pressure exhaust gas recirculation system.

[0020] Operation of fuel injection events can include the delivery of charge flow and fuel to the combustion chambers of the engine 102. According to certain embodiments, gaseous fuel can be injected into each cylinder 110 via a corresponding one of the injectors 120. Other embodiments contemplate gaseous fuel is fumigated into the charge flow upstream of the cylinders 110 of engine 102, such as, for example, upstream or downstream of the compressor 114b of turbocharger 144 at intake 104, at the intake manifold 118, and / or cylinder ports, or can be fumigated into the charge mixture in-cylinder. Combustion of the air-fuel mixture can be initiated with igniters 122, such as spark plugs, which include electrodes that create a spark at each of the cylinders 110. The delivery of the charge mixture, the fuel, and / or the ignition of the charge and fuel mixture in the combustion chambers may be, at least in part, electrically controlled by an electronic control system 130 of the engine system 100, as discussed further below.

[0021] In an embodiment, engine 102 includes pistons that reciprocate in the corresponding cylinders 110 during a four stroke cycle in which a crankshaft rotates 720 degrees per cycle. The term “four stroke” herein means the following four strokes - intake, compression, power, and exhaust - that the piston completes during two separate revolutions of the engine’s crankshaft, which is a combustion cycle. A stroke begins either at a top dead center (TDC) when the piston is at the top of cylinder, or at a bottom dead center (BDC), when the piston has reached its lowest point in the cylinder.

[0022] During the intake stroke, the piston descends away from cylinder head above the combustion chamber of the cylinder 110 to a bottom (not shown) of the cylinder 110, thereby reducing the pressure in the combustion chamber. A combustion charge is created in the combustion chamber by an intake of a charge from intake 104 through intake ports when the intake valves are opened.

[0023] During the compression stroke in a nominal or standard mode of operation, the intake valves and the exhaust valves are closed. The piston returns toward TDC and fuel is injected near TDC in a base injection event, and the compressed fuel-air mixture ignites in the combustion chamber after a short delay. The ignition of the air and fuel causes a rapid increase in pressure in the combustion chamber, which is applied to the piston during its power strokeAtty Docket No CMI002-00179 / 24-0030-SRC toward the BDC. Combustion phasing in combustion chamber is calibrated so that the increase in pressure in combustion chamber due to injection of a base fuel amount for the base injection event pushes the piston, providing a net positive in the force / work / power of the piston to rotate the crankshaft.

[0024] As discussed further below, during certain operating conditions of engine 102, a post injection fueling condition is indicated and a post injection fueling mode is selected to determine a post injection fuel amount for injection during the injection event after injection and combustion of the base injection fuel amount. The fuel provided for the post injection fuel amount is injected at a timing so that its combustion during the current combustion cycle provides less force / work / power to the piston than the base injection fuel amount and more energy is directed to the exhaust 106 to increase turbine output and aftertreatment system temperatures.

[0025] During the exhaust stroke, the piston is returned toward TDC while the exhaust valves are open. This action discharges the burnt products of the combustion of the fuel in the combustion chamber and expels the spent fuel-air mixture (exhaust gas) out through the exhaust valves into exhaust 106. The next combustion cycle occurs using these same intake and exhaust valve opening closing profdes, unless a cylinder deactivation condition or alternative valve lift condition is employed.

[0026] The control system 130 can include an electronic controller or electronic controller 132 that can be configured to control various operational aspects of engine system 100, including fuel injection events, air handling actuators for charge flow control, spark events, fuel rail pressure, and NOx reduction, among other operations. The electronic controller 132 can be implemented in a number of ways and in one or more electronic control units (ECUs). Further, the electronic controller 132 can execute operating logic that defines various control, management, and / or regulation functions. The operating logic may be in the form of one or more microcontroller or microprocessor routines stored in a non-transitory memory, dedicated hardware, such as a hardwired state machine, analog calculating machine, various types of programming instructions, and / or other forms as would occur to those skilled in the art.

[0027] The electronic controller 132 may be provided as a single component, or a collection of operatively coupled components, and may comprise digital circuitry, analog circuitry, or a hybrid combination of both of these types. When of a multi-component form, the electronicAtty Docket No CMI002-00179 / 24-0030-SRC controller 132 may have one or more components remotely located relative to the others in a distributed arrangement. The electronic controller 132 can include multiple processing units arranged to operate independently, in a pipeline processing arrangement, in a parallel processing arrangement, or the like. In one embodiment, the electronic controller 132 includes several programmable microprocessing units of a solid-state, integrated circuit type that are distributed throughout the engine system 100 that each includes one or more processing units and non- transitory memory.

[0028] For the depicted embodiment, the electronic controller 132 includes a computer network interface to facilitate communications using standard Controller Area Network (CAN) communications or the like among various system control units. It should be appreciated that the depicted modules or other organizational units of the electronic controller 132 refer to certain operating logic performing indicated operations that may each be implemented in a physically separate controller of the electronic controller 132 and / or may be virtually implemented in the same controller. Electronic controller 132 may include one or more organizational units or circuits that may be implemented in hardware and / or as computer instructions on a non-transient computer readable storage medium, and may be distributed across various hardware or computer based components.

[0029] Example and non-limiting implementation elements of control system 130 and / or organizational units of the electronic controller 132 include, for example, sensors such as intake sensors 134, engine sensors 136, exhaust / aftertreatment sensors 138, and / or other sensors providing any value determined herein, sensors providing any value that is a precursor to a value determined herein, datalink and / or network hardware including communication chips, oscillating crystals, communication links, cables, twisted pair wiring, coaxial wiring, shielded wiring, transmitters, receivers, and / or transceivers, logic circuits, hard-wired logic circuits, reconfigurable logic circuits in a particular non-transient state configured according to the module specification, any actuator including at least an electrical, hydraulic, or pneumatic actuator, a solenoid, an op-amp, analog control elements (springs, filters, integrators, adders, dividers, gain elements), and / or digital control elements. Sensors 134, 136, 138 and / or any other sensors may be physical sensors, virtual sensors, and / or combinations of physical and virtual sensors.

[0030] The electronic controller 132 and / or any of its constituent processors / controllers may include one or more signal conditioners, modulators, demodulators, Arithmetic Logic UnitsAtty Docket No CMI002-00179 / 24-0030-SRC(ALUs), Central Processing Units (CPUs), limiters, oscillators, control clocks, amplifiers, signal conditioners, filters, format converters, communication ports, clamps, delay devices, memory devices, Analog to Digital (A / D) converters, Digital to Analog (D / A) converters, and / or different circuitry or functional components as would occur to those skilled in the art to perform the desired communications.

[0031] Electronic controller 132 is configured to control operation of fuel injectors 120 to provide a commanded quantity of fuel at a commanded start of injection timing and end of injection timing, Electronic controller 132 is further configured to control igniters 122 to ignite the injected fuel at a commanded spark timing. Electronic controller 132 is further configured to control the positioning of intake throttle 105 and / or wastegate 107 in response to one or more air handling actuator commands that provide a desired charge flow. Electronic controller 132 is further configured to provide a NOx output estimate from engine 102 for NOx emissions reduction control of the aftertreatment system 116.

[0032] Referencing FIG. 2, according to certain embodiments, electronic controller 132 includes a final fuel command determination circuit 200. Final fuel command determination circuit 200 includes a desired fuel table 202 that evaluates inputs of engine speed, such as from an engine sensor 136, and desired torque, such as from an accelerator pedal position, to determine a base fuel quantity WfUei,base. The lambda control output determination block 204 receives an estimated charge flow Wair for the intake air or charge flow to engine 102. In an embodiment the estimated charge flow Wair is calculated using a volumetric efficiency model.

[0033] Lambda control output determination block 204 also receives the base fuel quantity Wtuetbase. Lambda control output determination block 204 determines a base fuel lambda target in response to the base fuel quantity Wfoetbase and estimated charge flow Wair. Lambda control output determination block 204 applies a maximum lambda limit Amax and a minimum lambda limit Amin to the base fuel lambda target to determine a control lambda output Aeontroi. The maximum lambda limit max can be, for example, a calibratable constant in an embodiment. The minimum lambda limit min is either a constant or table-based minimum limit in an embodiment.

[0034] The control lambda output Aeontroi is corrected using closed-loop control to determine the final fuel command Wfuetcmd to engine 102. For example, feedforward control block 206 receives control lambda output Aeontroi and estimated charge flow Wair. A feedforward fuel command Wfuetff is determined based on the control lambda output Aeontroi and the estimated chargeAtty Docket No CMI002-00179 / 24-0030-SRC flow Wair. For example, the feedforward fuel command Wfueyr can be determined at least in part by dividing the estimated charge flow Wair by the product of the stoichiometric air fuel ratio AFRstoich and the control lambda output Xcontroi as follows:

[0035] Equation 1

[0036] Control lambda output controi is also provided to difference operator 208 along with values for a sensed lambda X for feedback control. The sensed lambda X is determined, for example, by a lambda sensor in the exhaust flow, such as sensor 138, to provide a feedback lambda value for use in lambda correction. In an embodiment, the feedback lambda correction is multiplicative. Feedback control loop or block 210 receives the difference between the feedback sensed lambda X and the control lambda output Xcontroi. Feedback control block 210 also receives the feedforward fuel command Wfiiei.fr. Feedback control block 210 determines a feedback fuel command Wfuei,fb based on the feedback corrected control lambda output Xcontroi and estimated charge flow Wair and provides the feedback fuel command Wfuei,fb to summation operator 212. Summation operator 212 also receives the feedforward fuel command Wfiiei,fr from feedforward control block 206. The final fuel command Wfuei,cmd is output from summation operator 212 based on the sum of feedback fuel command Wfaetfb and feedforward fuel command WfUei.fr. The final fuel command Wfue md is used by electronic controller 132 to control the fuel amount injected into engine 102.

[0037] Referring to FIG. 3, electronic controller 132 can include a charge flow determination circuit 300 configured to determine positioning commands for one or more air handling actuators, such as intake throttle 105 and / or wastegate 107, based at least in part on the base fuel quantity Wfuei,base and a steady state lambda reference value. Charge flow determination circuit 300 includes an intake throttle position determination circuit 310 to determine a position of intake throttle 105. Charge flow determination circuit 300 also includes a wastegate position determination circuit 330 to determine a position of wastegate 107.

[0038] Intake throttle position determination circuit 310 includes a steady state lambda reference table 312 that determines a steady state lambda reference based on inputs of the desired torque for engine 102 and the speed of engine 102. The steady state lambda reference and base fuel quantity Wtuei,base are input to charge flow command conversion block 314, which determines a desired base air flow Wainbase based on the steady state lambda reference and base fuel quantity Wfuef ase.Atty Docket No CMI002-00179 / 24-0030-SRC

[0039] Desired base air flow Wair.base is received by first intake throttle feedback controller 316 and second intake throttle feedback controller 318. In an embodiment, first intake throttle feedback controller 316 and second intake throttle feedback controller 318 are proportionalintegral-derivative (PID) controllers. First intake throttle feedback controller 316 also receives a measured value for the charge flow such as from a mass air flow (MAF) sensor. First intake throttle feedback controller 316 determines a difference between the measured value for the charge flow and the desired base air flow Wair,base and outputs a feedback air flow Wair.i ii to summation operator 320. The desired base air flow Wair.base and feedback air flow Wair.FB are summed at summation operator 320 and provided as an input to the compressible flow equation at intake throttle position determination block 322.

[0040] Second intake throttle feedback controller 318 also receives inputs of engine speed for engine 102, charge pressure such as at intake manifold 118, and volumetric efficiency indicative of the actual air flow through intake 104. Second intake throttle feedback controller 318 determines a feedforward intake manifold pressure Pim,FF based on these values and the desired base air flow Wair.base. The feedforward intake manifold pressure Pim,FF is provided to the compressible flow equation at intake throttle position determination block 322. Intake throttle position determination block 322 calculates an intake throttle position using the compressible flow equation in order to provide the charge flow W to engine 102 based on the feedforward intake manifold pressure Pim,FF and feedback corrected desired base air flow Wair.base. In an embodiment, the charge flow W and compressible flow equation are expressed by the following:

[0041] Equation 2

[0042] In Equation 2, Aiat is the flow area through intake throttle 105, Pcois the compressor outlet pressure, Timis the intake manifold temperature, R is a gas constant, (p is a compressor head parameter, and II is the turbine pressure ratio of upstream pressure to downstream pressure. An intake throttle position command 324 is determined from the compressible flow equation, and electronic controller 132 is operable to position intake throttle 105 in the commanded position in response to intake throttle position command 324.

[0043] Wastegate position determination circuit 330 includes a feedforward control that includes an intake throttle pressure differential target table 332 that receives inputs of engine speed and a trapped mass air (TMA) reference. Trapped mass air is the mass air per cylinder per stroke, typically expressed as mg / stroke. Intake throttle pressure differential targe table 332 outputs aAtty Docket No CMI002-00179 / 24-0030-SRC target intake throttle pressure differential IAT AP to summation operator 334. Summation operator 334 sums the target intake throttle pressure differential IAT AP and the feedforward intake manifold pressure Pim.iT to determine a compressor outlet pressure reference value COPref for compressor 114b. Engine speed and the compressor outlet pressure reference value COPref are provided to wastegate position feedforward control table 336.

[0044] Wastegate position determination circuit 330 also includes a feedback control that includes trapped mass air (TMA) threshold block 340 that outputs a TMA threshold based on the engine speed input. The TMA threshold and TMA reference are provided to a closed loop enabling block 342. Closed loop enabling block 342 determines whether the wastegate position of wastegate 107 can be changed based on the mass airflow through turbine 114a. Closed loop enabling block 342 can include hysteresis control to prevent rapid cycling and changing of the wastegate position.

[0045] If closed loop control of the wastegate positioning is enabled, the closed looped control 344 of wastegate position determination circuit 330 is active. Closed loop control 344 determines a difference between a measured compressor outlet pressure COP and compressor outlet pressure reference value COPref at difference operator 346. This difference is provided to feedback control block 348 along with various wastegate control parameters indicated as Kpand Ki. The output from feedback control block 348 is summed with the output from wastegate position feedforward control table 336 at summation operator 338. The output from summation operator 338 is a wastegate position command 350. Electronic controller 132 is operable to position wastegate 107 in the commanded position in response to wastegate position command 350.

[0046] Referring to FIGs. 4A-4B, a process 400 for controlling operation of engine 102, such as with electronic controller 132, is illustrated. Process 400 includes an engine speed input 402 and a desired torque input 404 that are evaluated at a torque-to-fuel table operation 406, such as by employing desired fuel table 202, to determine the base fuel quantity Wtuetbase 407. Process 400 continues at base fuel lambda calculation operation 408. Base fuel lambda calculation operation 408 evaluates the base fuel quantity Wfuei,base 407 and a charge flow input 410 and calculates or determines a base fuel lambda target 409 to which transient limits are applied.

[0047] In process 400, a smart low lambda limit for transients 412 and a smart high lambda limit for aftertreatment 414 are applied to the base fuel lambda target 409 based on detection of a thermal management condition. The thermal management condition can be determined at thermalAtty Docket No CMI002-00179 / 24-0030-SRC management condition detection conditional 416 in response to a coolant temperature input 418 and an SCR inlet temperature input 420 that are evaluated at OR operation 422. If the coolant temperature input 418 is greater than a high desired temperature threshold, or if the SCR inlet temperature input 420 is greater than a high desired temperature threshold for the SCR inlet, the smart low lambda limit 412 for the transient is selected to minimize the impact of the any change in the base fuel lambda target 409 on the temperature condition. If the coolant temperature input 418 is less than a low desired temperature threshold, or if the SCR inlet temperature input 420 is less than a low desired temperature threshold for the SCR inlet, the smart high lambda limit 414 for the transient is selected so the change in the base fuel lambda target 407 increases the temperature condition. The smart low lambda limit 412 or smart high lambda limit 414 applied to the base fuel lambda target 409 results in a fuel lambda after limit 415, or control lambda output Acontroi.

[0048] Process 400 includes a feedforward and feedback control operation 424 to adjust the fuel lambda after limit 415 or control lambda output Xcontroi based on a sensed lambda value , similar to the control circuit 200 discussed above with respect to feedforward control block 206 and feedforward control block 210. The corrected lambda output from feedforward and feedback closed-loop control operation 424 and a charge flow input 426 are processed at fuel lambda calculation operation 428 to determine the final fuel command Wfaetcmd 429 to engine 102.

[0049] Process 400 also includes operations to enable or disable a post injection of fuel in response to detection of a thermal management condition at thermal management condition detect conditional 416. If the coolant temperature input 418 or SCR inlet temperature input 420 is higher than its corresponding high desired temperature threshold, then post injection fueling is disabled at operation 430. If the coolant temperature input 418 or SCR inlet temperature input 420 is lower than its corresponding low desired temperature threshold, then post injection fueling is enabled and a post injection fuel amount 433 to provide to engine 102 is selected at operation 432 based on engine conditions input 434. The post injection fuel amount 433 is injected after the main fuel injection of the fuel amount for final fuel command Wfuei,cmd 429 to contribute energy to the exhaust and aftertreatment system 116 rather than to the piston to respond to the detected thermal management condition.

[0050] Process 400 also includes operations to position air handling actuators that control the charge flow to engine 102, such as intake throttle 105 and wastegate 107. For example, process 400 includes a charge flow command conversion operation 438 to determine a charge flowAtty Docket No CMI002-00179 / 24-0030-SRC command 439. Charge flow command conversion operation 438 determines the charge flow command 439 based on the base fuel quantity Wfuei,base 407 from torque-to-fuel table operation 406 and a steady state lambda reference from a steady state lambda determination operation 440. Steady state lambda determination operation 440 may include a table, such as steady state reference lambda table 312, that determines the steady state reference lambda based on engine speed input 402 and desired torque input 404. The charge flow command 439 and a measured charge flow input 444 are evaluated at air handling control operation 442 to determine position commands 443 for air handling actuators, such as intake throttle 105 and / or wastegate 107, to control the charge flow to engine 102.

[0051] Process 400 also includes operations to provide a virtual NOx estimate 457 based at least in part on sensed lambda X that compensates for limitations at the upper limits of NOx sensors, such as sensor 138, to accurately measure NOx during transient conditions. For example, a NOx virtual sensor calculation operation 450 evaluates engine torque input 404, a charge pressure input 452 for the charge flow to engine 102, a charge temperature input 454 for the charge flow to engine 102, and a lambda input 456. The virtual NOx estimate 457 of the NOx output based on lambda input 456 and other inputs 404, 452, 454 is able to detect spikes in NOx outputs due to transient conditions of engine 102. The virtual NOx estimate 457 of the NOx output from NOx virtual sensor calculation operation 450 is provided to SCR control operation 458. SCR control operation 458 provides NOx reduction chemicals, such as urea, to a selective catalytic reduction (SCR) catalyst in aftertreatment system 116 to mitigate NOx emissions. Since NOx virtual sensor calculation operation 450 provides virtual NOx estimate 457 that improves the accuracy of the NOx determinations made by a physical NOx sensor during conditions that create potential spikes in NOx output from engine 102, SCR control operation 458 can be more accurately controlled during these conditions.

[0052] In an embodiment, the virtual estimate of the NOx output is performed by a regression analysis of several operating parameter inputs from system 100 and associated calibration coefficients. In one embodiment, the operating parameter inputs employed in the regression analysis include: a NOx constant calibration coefficient; a charge pressure and charge pressure calibration coefficient; a charge temperature and charge temperature calibration coefficient; a lambda and lambda calibration coefficient; an engine speed and engine speed calibration coefficient; an engine torque and engine torque calibration coefficient; a chargeAtty Docket No CMI002-00179 / 24-0030-SRC pressure, lambda, and charge pressure lambda calibration coefficient; a charge temperature, lambda, and charge temperature lambda calibration coefficient; an engine torque, lambda, and engine torque lambda calibration coefficient; and a lambda and lambda squared calibration coefficient.

[0053] Referring to FIG. 5, an embodiment of electronic controller 132 can include an ignition control circuit 500 that is configured with a fuel command determination circuit 502 that is similar to fuel command determination circuit 200 discussed above. The illustrated embodiment of fuel command determination circuit 502 differs in that a smart lambda limit determination block 502 is provided. Smart lambda limit determination block can determine a iimit. The Aihmt can be used at lambda control output determination block 204 along with base fuel quantity Wfoetbase and the charge flow estimate to determine control lambda output Acontroi. Which is corrected by a sensed lambda in closed-loop control to determine the final fuel command Wfuei,Cmd as discussed above.

[0054] Ignition control circuit 500 also include a spark timing determination circuit 510, an end-of-inj ection determination circuit 530, and a rail pressure determination circuit 540. Spark timing determination circuit 510 includes a spark timing table 512 that determines a base spark timing STbase in response to engine speed and total fueling (e.g. final fuel command Wfuei,cmd) provided by final fuel command Wfiietcmd. The base spark timing STbase is corrected for the sensed lambda A at a lambda correction block 514 to determine a lambda-corrected spark timing ST?.. The lambda-corrected spark timing ST is then modified for transient conditions at transient modifier block 516. The transient condition modifiers can include, for example, modifiers to the spark timing for coolant temperature and intake manifold temperature.

[0055] Spark timing determination circuit 510 also includes a knock control block 518. Knock control block 518 can provide adjustments in the spark timing to mitigate knock conditions, such as during transients or other operating conditions, such as by delaying the spark timing. The lambda-corrected sparking timing ST?. modified for transients (if any) and for knock (if any) are summed at spark timing command determination operator 520. Spark timing determination operator 520 outputs a spark timing command ST based on the lambda-corrected sparking timing ST?, as modified for transients and for knock. Electronic controller 132 is operable to control igniters 122 to ignite the injected fuel amount based on spark timing command ST.

[0056] End-of-inj ection determination circuit 530 includes an end-of-inj ection (EOI) / start- of-injection (SOI) table 532. F.OI / SO1 table 532 outputs a steady state end-of-inj ection EOIsteadyAtty Docket No CMI002-00179 / 24-0030-SRC based on engine speed and TMA. Steady state end-of-inj ection EOIsteady is adjusted for transients at transient EOI adjustment block 534. Transient EOI adjustment block 534 outputs a commanded end-of-inj ection EOI. Electronic controller 132 is operable to control fuel injectors 120 to inject the final fuel command WfUei,cmd to engine 102 at the commanded EOI as adjusted for transients.

[0057] Rail pressure determination circuit 540 includes a rail pressure table 542 that receives inputs of engine speed and final fuel command Wtuei,cmd (total fueling) to engine 102. The rail pressure table 542 determines a rail pressure command that is provided to, for example, a rail pressure controller 544. Rail pressure controller 544 controls the rail pressure of the common rail connecting fuel injectors 120 in response to the rail pressure command.

[0058] Various aspects of the present disclosure are contemplated. For example, according to one aspect a system for controlling combustion in an internal combustion engine is provided. The system includes an electronic controller configured to determine a base fuel quantity in response to a desired torque output from the internal combustion engine and a speed of the internal combustion engine; determine a control lambda output based on the base fuel quantity, a charge flow to the internal combustion engine, and one or more lambda limits that limit the control lambda output; determine a correction for the control lambda output with closed loop control in response to a feedback lambda that is sensed during operation of the internal combustion engine; determine a final fuel command for a quantity of fuel to injection into the internal combustion engine based on the corrected control lambda output and the charge flow; and inject the quantity of fuel into the internal combustion engine in response to the final fuel command.

[0059] In an embodiment, the electronic controller is configured to determine one or more commands for positioning one or more air handling actuators to control the charge flow to the internal combustion engine in response to the base fuel quantity, the speed of the internal combustion engine, and the desired torque output.

[0060] In a further embodiment, the one or more air handling actuators include an intake throttle and a wastegate. The one or more commands include an intake throttle position command and a wastegate position command.

[0061] In a further embodiment, the electronic controller is configured to: determine a desired base charge flow to the internal combustion engine based on the base fuel quantity and a steady state lambda for the desired torque output and the speed; correct the desired base chargeAtty Docket No CMI002-00179 / 24-0030-SRC flow in response to a sensed charge flow; determine a feedforward intake manifold pressure in response to the desired base charge flow, the speed, a charge pressure of the charge flow, and an amount of the charge flow to the internal combustion engine; and determine the intake throttle position command based on the corrected desired base charge flow and the feedforward intake manifold pressure.

[0062] In a further embodiment, the electronic controller is configured to determine the wastegate position command in response to a target pressure differential across the intake throttle and a difference between a compressor outlet pressure reference and a measured compressor outlet pressure.

[0063] In an embodiment, the one or more lambda limits include: a low lambda limit for transient conditions of the internal combustion engine; and a high lambda limit for temperature conditions of a selective catalytic reduction device that receives NOx output from the internal combustion engine.

[0064] In a further embodiment, the electronic controller is configured to: apply the low lambda limit to the control lambda in response to a coolant temperature being greater than a high desired coolant temperature threshold or a temperature of the selective catalytic reduction device being greater than a high desired aftertreatment temperature threshold; and apply the high lambda limit to the control lambda in response to the coolant temperature being less than a low desired coolant temperature threshold or the temperature of the selective catalytic reduction device being less than a low desired aftertreatment temperature threshold.

[0065] In an embodiment, the electronic controller is configured to: disable post fuel injection in response to a coolant temperature being greater than a high desired coolant temperature threshold or a temperature of the selective catalytic reduction device being greater than a high desired aftertreatment temperature threshold; and inject a post fuel injection amount in response to the coolant temperature being less than a low desired coolant temperature threshold or the temperature of the selective catalytic reduction device being less than a low desired aftertreatment temperature threshold.

[0066] In an embodiment, the electronic controller is configured to estimate a NOx amount output from the engine in response to the sensed lambda, a torque output from the internal combustion engine, a pressure of the charge flow, and a temperature of the charge flow.Atty Docket No CMI002-00179 / 24-0030-SRC

[0067] In an embodiment, the electronic controller is configured to determine a spark timing for ignition of the quantity of fuel, wherein the spark timing is corrected based on the sensed lambda, intake manifold temperature, and coolant temperature, and further wherein the spark timing is adjusted to mitigate knock.

[0068] In an embodiment, the closed loop control includes feedforward control based on the control lambda and the charge flow and feedback control based on the control lambda output and a sensed lambda from operation of the internal combustion engine.

[0069] In an embodiment, the system includes the internal combustion engine. The internal combustion engine includes a plurality of cylinders for receiving an charge flow and fuel, a plurality of igniters associated with respective ones of the plurality of cylinders; an intake throttle; and a turbocharger including a compressor that compresses the charge flow and is operated by a turbine that uses exhaust produced by combustion in the plurality of cylinders, wherein the turbine includes a wastegate.

[0070] According to another aspect of the present disclosure, a method for controlling combustion in an internal combustion engine is disclosed. The method includes determining a base fuel quantity in response to a desired torque output from the internal combustion engine and a speed of the internal combustion engine; determining a control lambda output based on the base fuel quantity, a charge flow to the internal combustion engine, and one or more lambda limits that limit the control lambda output; determining a correction for the control lambda output with closed loop control in response to a feedback lambda that is sensed during operation of the internal combustion engine; determining a final fuel command for a quantity of fuel to injection into the internal combustion engine based on the corrected control lambda output and the charge flow; and injecting the quantity of fuel into the internal combustion engine in response to the final fuel command.

[0071] In an embodiment, the method includes determining one or more commands for positioning one or more air handling actuators to control the charge flow to the internal combustion engine in response to the base fuel quantity, the speed of the internal combustion engine, and the desired torque output.

[0072] In a further embodiment, the one or more air handling actuators include an intake throttle and a wastegate. The one or more commands include an intake throttle position command and a wastegate position command.Atty Docket No CMI002-00179 / 24-0030-SRC

[0073] In a further embodiment, the method includes determining a desired base charge flow to the internal combustion engine based on the base fuel quantity and a steady state lambda for the desired torque output and the speed; correcting the desired base charge flow in response to a sensed charge flow; determining a feedforward intake manifold pressure in response to the desired base charge flow, the speed, a charge pressure of the charge flow, and an amount of the charge flow to the internal combustion engine; and determining the intake throttle position command based on the corrected desired base charge flow and the feedforward intake manifold pressure.

[0074] In a further embodiment, the method includes determining the wastegate position command in response to a target pressure differential across the intake throttle and a difference between a compressor outlet pressure reference and a measured compressor outlet pressure.

[0075] In an embodiment, the one or more lambda limits include a low lambda limit for transient conditions of the internal combustion engine, and a high lambda limit for temperature conditions of a selective catalytic reduction device that receives NOx output from the internal combustion engine.

[0076] In a further embodiment, the method includes applying the low lambda limit to the control lambda in response to a coolant temperature being greater than a high desired coolant temperature threshold or a temperature of the selective catalytic reduction device being greater than a high desired aftertreatment temperature threshold; and applying the high lambda limit to the control lambda in response to the coolant temperature being less than a low desired coolant temperature threshold or the temperature of the selective catalytic reduction device being less than a low desired aftertreatment temperature threshold.

[0077] In an embodiment, the method includes disabling post fuel injection in response to a coolant temperature being greater than a high desired coolant temperature threshold or a temperature of the selective catalytic reduction device being greater than a high desired aftertreatment temperature threshold; and injecting a post fuel injection amount in response to the coolant temperature being less than a low desired coolant temperature threshold or the temperature of the selective catalytic reduction device being less than a low desired aftertreatment temperature threshold.Atty Docket No CMI002-00179 / 24-0030-SRC

[0078] In an embodiment, the method includes estimating a NOx amount output from the engine in response to the sensed lambda, a torque output from the internal combustion engine, a pressure of the charge flow, and a temperature of the charge flow.

[0079] In an embodiment, the closed loop control includes feedforward control based on the control lambda and the charge flow and feedback control based on the control lambda output and a sensed lambda from operation of the internal combustion engine.

[0080] While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment(s), but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as permitted under the law. Furthermore it should be understood that while the use of the word preferable, preferably, or preferred in the description above indicates that feature so described may be more desirable, it nonetheless may not be necessary and any embodiment lacking the same may be contemplated as within the scope of the invention, that scope being defined by the claims that follow. In reading the claims it is intended that when words such as “a,” “an,” “at least one” and “at least a portion” are used, there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. Further, when the language “at least a portion” and / or “a portion” is used the item may include a portion and / or the entire item unless specifically stated to the contrary.

Claims

Atty Docket No CMI002-00179 / 24-0030-SRCWHAT IS CLAIMED IS:

1. A system for controlling combustion in an internal combustion engine, the system comprising: an electronic controller configured to: determine a base fuel quantity in response to a desired torque output from the internal combustion engine and a speed of the internal combustion engine; determine a control lambda output based on the base fuel quantity, a charge flow to the internal combustion engine, and one or more lambda limits that limit the control lambda output; determine a correction for the control lambda output with closed loop control in response to a feedback lambda that is sensed during operation of the internal combustion engine; determine a final fuel command for a quantity of fuel to injection into the internal combustion engine based on the corrected control lambda output and the charge flow; and inject the quantity of fuel into the internal combustion engine in response to the final fuel command.

2. The system of claim 1, wherein the electronic controller is configured to: determine one or more commands for positioning one or more air handling actuators to control the charge flow to the internal combustion engine in response to the base fuel quantity, the speed of the internal combustion engine, and the desired torque output.

3. The system of claim 2, wherein: the one or more air handling actuators include an intake throttle and a wastegate; and the one or more commands include an intake throttle position command and a wastegate position command.

4. The system of claim 3, wherein the electronic controller is configured to: determine a desired base charge flow to the internal combustion engine based on the base fuel quantity and a steady state lambda for the desired torque output and the speed;Atty Docket No CMI002-00179 / 24-0030-SRC correct the desired base charge flow in response to a sensed charge flow; determine a feedforward intake manifold pressure in response to the desired base charge flow, the speed, a charge pressure of the charge flow, and an amount of the charge flow to the internal combustion engine; and determine the intake throttle position command based on the corrected desired base charge flow and the feedforward intake manifold pressure.

5. The system of claim 4, wherein the electronic controller is configured to determine the wastegate position command in response to a target pressure differential across the intake throttle and a difference between a compressor outlet pressure reference and a measured compressor outlet pressure.

6. The system of claim 1, wherein the one or more lambda limits include: a low lambda limit for transient conditions of the internal combustion engine; and a high lambda limit for temperature conditions of a selective catalytic reduction device that receives NOx output from the internal combustion engine.

7. The system of claim 6, wherein the electronic controller is configured to: apply the low lambda limit to the control lambda in response to a coolant temperature being greater than a high desired coolant temperature threshold or a temperature of the selective catalytic reduction device being greater than a high desired aftertreatment temperature threshold; and apply the high lambda limit to the control lambda in response to the coolant temperature being less than a low desired coolant temperature threshold or the temperature of the selective catalytic reduction device being less than a low desired aftertreatment temperature threshold.

8. The system of claim 1, wherein the electronic controller is configured to: disable post fuel injection in response to a coolant temperature being greater than a high desired coolant temperature threshold or a temperature of the selective catalytic reduction device being greater than a high desired aftertreatment temperature threshold; andAtty Docket No CMI002-00179 / 24-0030-SRC inject a post fuel injection amount in response to the coolant temperature being less than a low desired coolant temperature threshold or the temperature of the selective catalytic reduction device being less than a low desired aftertreatment temperature threshold.

9. The system of claim 1, wherein the electronic controller is configured to: estimate a NOx amount output from the engine in response to the sensed lambda, a torque output from the internal combustion engine, a pressure of the charge flow, and a temperature of the charge flow.

10. The system of claim 1, wherein the electronic controller is configured to: determine a spark timing for ignition of the quantity of fuel, wherein the spark timing is corrected based on the sensed lambda, intake manifold temperature, and coolant temperature, and further wherein the spark timing is adjusted to mitigate knock.

11. The system of claim 1, wherein the closed loop control includes: feedforward control based on the control lambda output and the charge flow; and feedback control based on the control lambda output and a sensed lambda from operation of the internal combustion engine.

12. The system of claim 1, further comprising the internal combustion engine, the internal combustion engine including: a plurality of cylinders for receiving the charge flow and fuel; a plurality of igniters associated with respective ones of the plurality of cylinders; an intake throttle; and a turbocharger including a compressor that compresses the charge flow and is operated by a turbine that uses exhaust produced by combustion in the plurality of cylinders, wherein the turbine includes a wastegate.

13. A method for controlling combustion in an internal combustion engine, the method comprising:Atty Docket No CMI002-00179 / 24-0030-SRC determining a base fuel quantity in response to a desired torque output from the internal combustion engine and a speed of the internal combustion engine; determining a control lambda output based on the base fuel quantity, a charge flow to the internal combustion engine, and one or more lambda limits that limit the control lambda output; determining a correction for the control lambda output with closed loop control in response to a feedback lambda that is sensed during operation of the internal combustion engine; determining a final fuel command for a quantity of fuel to injection into the internal combustion engine based on the corrected control lambda output and the charge flow; and injecting the quantity of fuel into the internal combustion engine in response to the final fuel command.

14. The method of claim 13, further comprising: determining one or more commands for positioning one or more air handling actuators to control the charge flow to the internal combustion engine in response to the base fuel quantity, the speed of the internal combustion engine, and the desired torque output.

15. The method of claim 14, wherein: the one or more air handling actuators include an intake throttle and a wastegate; and the one or more commands include an intake throttle position command and a wastegate position command.

16. The method of claim 15, further comprising: determining a desired base charge flow to the internal combustion engine based on the base fuel quantity and a steady state lambda for the desired torque output and the speed; correcting the desired base charge flow in response to a sensed charge flow; determining a feedforward intake manifold pressure in response to the desired base charge flow, the speed, a charge pressure of the charge flow, and an amount of the charge flow to the internal combustion engine; and determining the intake throttle position command based on the corrected desired base charge flow and the feedforward intake manifold pressure.Atty Docket No CMI002-00179 / 24-0030-SRC17. The method of claim 16, further comprising determining the wastegate position command in response to a target pressure differential across the intake throttle and a difference between a compressor outlet pressure reference and a measured compressor outlet pressure.

18. The method of claim 13, wherein the one or more lambda limits include: a low lambda limit for transient conditions of the internal combustion engine; and a high lambda limit for temperature conditions of a selective catalytic reduction device that receives NOx output from the internal combustion engine.

19. The method of claim 18, further comprising: applying the low lambda limit to the control lambda in response to a coolant temperature being greater than a high desired coolant temperature threshold or a temperature of the selective catalytic reduction device being greater than a high desired aftertreatment temperature threshold; and applying the high lambda limit to the control lambda in response to the coolant temperature being less than a low desired coolant temperature threshold or the temperature of the selective catalytic reduction device being less than a low desired aftertreatment temperature threshold.

20. The method of claim 13, further comprising: disabling post fuel injection in response to a coolant temperature being greater than a high desired coolant temperature threshold or a temperature of the selective catalytic reduction device being greater than a high desired aftertreatment temperature threshold; and injecting a post fuel injection amount in response to the coolant temperature being less than a low desired coolant temperature threshold or the temperature of the selective catalytic reduction device being less than a low desired aftertreatment temperature threshold.

21. The method of claim 13, further comprising: estimating a NOx amount output from the engine in response to the sensed lambda, a torque output from the internal combustion engine, a pressure of the charge flow, and a temperature of the charge flow.Atty Docket No CMI002-00179 / 24-0030-SRC22. The method of claim 13, wherein the closed loop control includes: feedforward control based on the control lambda output and the charge flow; and feedback control based on the control lambda output and a sensed lambda from operation of the internal combustion engine.

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