Apparatuses, methods, systems, and techniques of cylinder misfire detection

Abstract

A system includes an internal combustion engine including a plurality of cylinders and an electronic control system operatively coupled with the internal combustion engine. The electronic control system is configured to store a vector library comprising a plurality of classification vectors empirically determined for a plurality of engine operating conditions, receive a plurality of engine operating parameters including an engine speed parameter, an engine fueling parameter, a EGR parameter, a crank angle parameter, and an exhaust manifold pressure parameter, determine a interpolation vector, a classification vector, a discriminant function, and a misfire threshold in response the engine operating parameters, and detect a cylinder misfire in response to the misfire threshold and the discriminant function parameter.

Description

APPARATUSES, METHODS, SYSTEMS, AND TECHNIQUES OF CYLINDER MISFIRE DETECTIONCROSS-REFERENCE

[0001] The present disclosure claims priority to and the benefit of U.S. Application No 63 / 599,208 filed November 15, 2023 and the same is hereby incorporated by reference.TECHNICAL FIELD

[0002] The present disclosure relates to controls for reciprocating piston engines and to apparatuses, methods, systems, and techniques of cylinder misfire detection.BACKGROUND

[0003] Reciprocating piston internal engines may experience a number of malfunctions such as injector failure, misaligned valve mechanisms, stuck valves, compression failure, among others, that can cause a cylinder to misfire and produce no power or mistimed power. Due to such malfunction, engines may face a loss of performance, repair cost, and downtime due to progressive damage. Additionally, such malfunctions may result in engine non-compliance with emissions limits which may mandate limits on the occurrence of misfire and / or resulting emissions. A number of proposals have been made for detecting engine misfire. Existing proposals suffer from a number of disadvantages and shortcomings. There remains a significant need for the unique apparatuses, methods, systems, and techniques of the present disclosure.DISCLOSURE OF EXAMPLE EMBODIMENTS

[0004] For the purposes of clearly, concisely and exactly describing example embodiments of the present disclosure, the manner and process of making and using the same, and to enable the practice, making and use of the same, reference will now be made to certain example embodiments, including those illustrated in the figures, and specific language will be used to describe the same. It shall nevertheless be understood that no limitation of the scope of the invention is thereby created and that the invention includes and protects such alterations, modifications, and further applications of the example embodiments as would occur to one skilled in the art.SUMMARY OF THE DISCLOSURE

[0005] Example embodiments include unique apparatuses, methods, systems, and techniques to detect misfire events in an internal combustion engine. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings.BRIEF DESCRIPTION OF THE FIGURES

[0006] Fig. 1 is a schematic diagram illustrating certain aspects of an example engine system.

[0007] Figs. 2-10 are schematic diagram illustrating certain aspects of example controls.DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0008] With reference to Fig. 1, there are illustrated certain aspects of an example powertrain system 10 (also referred to as system 10). In the illustrated embodiment, system 10 includes an internal combustion engine 12 including an intake manifold 14 which is fluidly coupled to an outlet of a compressor 16 of a turbocharger 18 via an intake conduit 20. Compressor 16 includes a compressor inlet coupled to an intake conduit 22 for receiving fresh air therefrom. The compressor 16 is mechanically coupled to a turbine 26 via a drive shaft 28. The turbine 26 includes a turbine inlet fluidly coupled to an exhaust manifold 30 of engine 12 via an exhaust conduit 32. System 10 may include an intake air cooler 24 disposed in line with intake conduit 20 between compressor 16 and intake manifold 14. System 10 may also include an intake air throttle (IAT) 21. In other embodiments, the engine 10 may be of a naturally aspirated type and may omit turbocharger 18.In further embodiments, the engine 10 may be of a supercharged type and one or more engine- driven compressors may be provided in lieu of exhaust-driven turbocharger 18.

[0009] In the illustrated embodiment the engine 12 is a reciprocating piston, direct injection, compression ignition engine configured to combust diesel fuel. It shall nevertheless be appreciated that the engine 12 may also be provided in other forms including one or more of port injection, spark ignition, and configured to combust other types of fuel such as natural gas or other gaseous fuel or gasoline. It shall be further appreciated that the teachings of the present disclosure may be implemented in connection with essentially any reciprocating piston engine.

[0010] The engine 12 includes a plurality of cylinders 12a-12f containing respective reciprocating pistons each connected to a crankshaft by a corresponding connecting rod (not shown) to reciprocally move within the respective cylinder 12a-12f in a standard manner for four- stroke engine operation. Each cylinder 12a-12f includes a combustion chamber with appropriate intake and exhaust valves (not shown) and fuel injectors 13a-13f. Fuel injectors 13a-13f are configured to operate in response to signals from electronic controls such as those further described herein. Fuel injectors 13a-13f receive fuel from a fuel source (not shown) in fluid communication therewith.

[0011] System 10 includes an EGR valve 38 disposed in-line with an EGR conduit 36 fluidly coupled at one end to intake conduit 20 and at an opposite end to exhaust conduit 32. An EGR cooler 40 may optionally be disposed in-line with EGR conduit 36 between EGR valve 38 and intake conduit 20 as shown in phantom in Fig. 1.

[0012] System 10 includes an electronic control system (ECS) 23. In the illustrated form the electronic control system 23 includes a controller 42 which may be provided as an electronic control unit (ECU) or an electronic control module (ECM). The electronic control system 23 may further include additional controllers which may be provided as additional ECU or ECM units in communication with one another over a communication network such as a controller area network (CAN). In some embodiments, one or more parts or components of the electronic control system 23, for example, the controller 42, may be provided in the form of an electronic computing system of a diagnostic apparatus configured to be operatively coupled with an engine. In some such embodiments, the controller 42 or other electronic computing system components may receive information such as one or more additional signal(s) permitting the controller 42 or other electronic computing system components to evaluate or determine a cylinder firing sequence associated withan engine being diagnosed or otherwise under evaluation. Such information may comprise, for example, a signal from a crank “reference” marking sensor indicating an angle (e.g., an angle corresponding to top-dead-center (TDC), bottom-dead-center (BDC), or another angle for a given cylinder). Provision of such information to the controller 42 or other electronic computing system components may include translation or conversion of one or more signals to accomplish or facilitate the foregoing acts and capabilities.

[0013] The controller 42 is generally operable to control and manage operational aspects of engine 12. The controller 42 includes memory 45 as well as a number of inputs and outputs for interfacing with various sensors and systems coupled to engine 12. The controller 42 can be an electronic circuit comprised of one or more components, including digital circuitry, analog circuitry, or both. The controller 42 may be a software and / or firmware programmable type; a hardwired, dedicated state machine; or a combination of these. In one embodiment, controller 42 is of a programmable microcontroller solid-state integrated circuit type that includes memory 45 and one or more central processing units. Memory 45 can be comprised of one or more components and can be of any volatile or nonvolatile type, including the solid-state variety, the optical media variety, the magnetic variety, a combination of these, or other arrangements. The controller 42 can include signal conditioners, signal format converters (such as analog-to-digital and digital-to-analog converters), limiters, clamps, filters, and the like as needed to perform various control and regulation operations described herein.

[0014] The controller 42 may be configured for regulation and control of the overall operation of the engine 12. Alternatively, controller 42 may be configured for regulation and control of a set of controlled aspects of engine 12. The controller 42 is configured to store controller executable instructions and to execute these instructions to provide for regulation and control of the engine 12. These controller executable instructions may be configured in accordance with one or more of the control processes described herein as well as other control processes.

[0015] The controller 42 is configured to receive as input or otherwise access a number of inputs for receiving signals from various sensors or sensing systems associated with system 10. For example, system 10 includes an engine speed sensor 44 electrically connected to an engine speed input, ES, of the controller 42 via signal path 46. Engine speed sensor 44 is operable to sense rotational speed of the engine 12 and produce an engine speed signal on signal path 46 indicative of engine rotational speed. Engine speed sensor 44 may be provided as a crankshaftspeed sensor. In one embodiment, engine speed sensor 44 is a Hall effect sensor operable to determine engine speed. Alternatively, engine speed sensor 44 may be any other known sensor operable as just described including, but not limited to, a variable reluctance sensor or the like. System 10 further includes a fuel system sensor 47 electrically connected to fuel system input, FS, of the controller 42 via signal path 71. In the illustrated embodiment, fuel system sensor 47 is provided as a rail pressure sensor configured to sense a pressure associated with a fuel rail 49 configured to supply fuel to fuel injector 13a-13f.

[0016] System 10 may include an intake manifold temperature sensor 48 disposed in fluid communication with the intake manifold 14 of engine 12, and electrically connected to an intake manifold temperature input (IMT) of the controller 42 via signal path 50. Intake manifold temperature sensor 48 is operable to provide a temperature signal on signal path 50 indicative of the temperature of air charge flowing into the intake manifold 14, wherein the air charge flowing into the intake manifold 14 is generally made up of fresh air supplied by the turbocharger compressor 16 combined with recirculated exhaust gas supplied by EGR valve 38.

[0017] System 10 may also include an intake manifold pressure sensor 52 disposed in fluid communication with intake manifold 14 and electrically connected to an intake manifold pressure input (IMP) of the controller 42 via signal path 54. Alternatively, pressure sensor 52 may be disposed in fluid communication with intake conduit 20. In any case, pressure sensor 52 is operable to produce a pressure signal on signal path 54 indicative of air pressure within intake conduit 20 and intake manifold 14.

[0018] System 10 may also include an exhaust manifold pressure sensor 72 disposed in fluid communication with exhaust manifold 30 and electrically connected to an exhaust manifold pressure input (EMP) of the controller 42 via signal path 72 a. In other forms, pressure sensor 72 may be disposed in the fluid communication with exhaust conduit 32. Pressure sensor 72 is operable to produce a pressure signal on signal path 72 indicative of gas pressure within exhaust conduit 32 and exhaust manifold 30. In other forms, one or both of exhaust manifold pressure sensor 72 and exhaust manifold temperature sensor 74 may be absent from system 10, and exhaust pressure and temperature may be calculated or estimated from other parameters. For example, in forms where the exhaust manifold pressure sensor is absent exhaust manifold pressure may be calculated or estimated using a number of techniques or models such as via the speed density equation or by other calculations or estimations.

[0019] System 10 may include a differential pressure sensor, or DP sensor, 56 fluidly coupled at one end to EGR conduit 36 adjacent to an exhaust gas inlet of EGR valve 38 via conduit 60, and fluidly coupled at its opposite end to EGR conduit 36 adjacent to an exhaust gas outlet of EGR valve 38 via conduit 58. Alternatively, DP sensor 56 may be coupled across another flow restriction mechanism disposed in-line with EGR conduit 36. In either case, the DP sensor 56 may be of known construction and is electrically connected to a DP input of the controller 42 via signal path 62. DP sensor 62 is operable to provide a differential pressure signal on signal path 62 indicative of the pressure differential across EGR valve 38 or other flow restriction mechanism disposed in-line with EGR conduit 36. Nonetheless, it should be recognized that in other embodiments EGR valve 38, DP sensor 56, and associated conduits, coolers, and the like, may be absent.

[0020] The controller 42 is also configured to provide a number of outputs for controlling one or more engine functions associated with system 10. For example, EGR valve 38 is electrically connected to an EGR valve output (EGRV) of controller 42 via signal path 64. The controller 42 is operable, as is known in the art, to produce an EGR valve control signal on signal path 64 to correspondingly control the position of EGR valve 38 relative to a reference position in a known manner. The controller 42 is accordingly operable to control EGR valve 38 to selectively provide a flow of recirculated exhaust gas from exhaust manifold 30 to intake manifold 14. Accordingly, while the composition of gas flowing along pathway 33 changes from (a) compressed air, (b) to an air / fuel charge, and then (c) to exhaust — when EGR valve 38 is closed — such composition may also include various amounts of recirculated exhaust gas when EGR valve 38 is open. In certain embodiments, the controller 42 may also include one or more outputs for controlling operation of a turbocharger mechanism such as a wastegate for turbocharger 18 (if present) a variable geometry actuator (if present).

[0021] The controller 42 is further configured to provide a plurality of fueling command outputs for controlling operation of each fuel injector 13a-13f or to another number of fuel injectors where present in other embodiments and forms of system 10. The signal paths for outputs FC are also collectively designated by reference numeral 70 in Fig. 1; however, it should be understood that the timing of fuel injected by each injector 13a-13f can be independently controlled with controller 42. In addition to the timing of fuel injection, the controller 42 can also regulate theamount of fuel injected. Typically, the fuel amount varies with the number and duration of injector-activating pulses provided to injectors 13a-13f.

[0022] The system 10 may also include an aftertreatment system 80 providing aftertreatment of exhaust gases before discharge through a conduit 94. During engine operation, exhaust gas flows from turbine outlet 27 through exhaust conduit 34 in fluid communication therewith. Conduit 34 is also in fluid communication with aftertreatment system 80 which receives the exhaust gas from turbine 26 for aftertreatment. Aftertreatment system 80 can include a number of catalysts configured to chemically convert and / or remove undesirable constituents from the exhaust stream before discharge into the environment. In the illustrated form, aftertreatment system 80 includes a diesel particulate filter (DPF) 84 configured to reduce emissions of particulates. The illustrated form of aftertreatment system 80 also includes a selective catalytic reduction (SCR) catalyst 86 configured to catalyze the reduction of oxides of nitrogen (NOx) in conjunction with a reducing agent such as diesel exhaust fluid (DEF) which is introduced into the exhaust stream by a doser or injector (not shown) typically upstream of the SCR catalyst 86. In other embodiments, aftertreatment system 80 may include additional or alternative catalysts including, for example, oxidation catalysts and ammonia slip catalysts, and other catalysts as would occur to one of skill in the art with the benefit of the present disclosure.

[0023] For nominal operation, the temperature of one or more portions of aftertreatment system 80 may need to achieve certain temperature conditions. For example, the SCR catalyst 84 may need to achieve a minimum temperature in order to operate as intended or desired. Additionally, for certain regeneration modes, even higher temperatures need to be reached from time-to-time. For example, the DPF 84 may require elevated temperature for periodic regeneration to eliminated accumulated particulate matter.

[0024] System 10 is configured to drive a load 79. In some embodiments, system 10 may be configured to propel a vehicle and the load L may be a propulsion load imposed on a driveline operatively coupled with system 10 including a number of load components such as aerodynamic resistance, rolling resistance, and grade / gravitational resistance to name several examples. The driveline operatively coupled with system 10 may include, for example, a transmission, a drive shaft, a differential, and drive wheels. In some embodiments, the load 79 may be a generator, and system 10 may be configured as a generator set. In other embodiments, load L may comprise apump, compressor, or another type of load as will occur to one of skill in the art with the benefit of the present disclosure.

[0025] With reference to Fig. 2, there are illustrated controls 100 which may be implemented in and operated by one or more components of an electronic control system such as controller 42 and / or other components of ECS 23 or another electronic control system. Controls 100 are configured and operable to detect misfire of a plurality of cylinders of an engine.

[0026] In the illustrated example, controls 100 are configured and operable to detect misfire of cylinders 12a-12f of engine 12. In other embodiments, controls 100 may be configured and operable to detect misfire of different numbers of cylinders of other engines.

[0027] Controls 100 include cylinder misfire detectors 120a-120f which are configured and operable to separately detect misfire of respective ones of cylinders 12a-12f In other words, cylinder detector 120a is configured and operable to detect misfire of cylinder 12a, cylinder detector 120b is configured and operable to detect misfire of cylinder 12b, cylinder detector 120c is configured and operable to detect misfire of cylinder 12c, and so forth through to and including cylinder detector 120f and cylinder 12f

[0028] Cylinder misfire detectors 120a-120f are configured and operable to output respective ones of misfire determination parameters 122a-122f which correspond to respective ones of cylinders 12a-12f. In other words, cylinder detector 120a is configured and operable to output misfire determination parameter 122a corresponding to cylinder 12a, cylinder detector 120b is configured and operable to detect misfire of cylinder 12b, cylinder detector 120c is configured and operable to detect misfire of cylinder 12c, and so forth through to and including cylinder detector 120f, misfire determination parameter 122f, and cylinder 12f.

[0029] Cylinder misfire detectors 120a-120f are configured and operable to receive a plurality of engine operating parameters 102 during operation of an associated engine system. Engine operating parameters 102 may be based upon outputs from a plurality of sensors, for example, an engine speed sensor, an EGR valve position sensor, and an exhaust manifold pressure sensors. Engine operating parameters 102 may be based upon control parameters determined by an electronic control system, for example, an engine fueling control parameter, and an EGR valve position control parameter. Cylinder misfire detectors 120a-120f are further configured and operable to receive calibration parameters 112 which may be received and stored during calibrationof an associated engine system and thereafter accessed or utilized by cylinder misfire detectors 120a-120f.

[0030] With reference to Fig. 3, there are illustrated further aspects of controls 100 in the form of controls 120n which may be implemented in multiple instances and provided in each of cylinder misfire detectors 120a-120f. Controls 120n include misfire detection logic 220 which may be configured and implemented to detect misfire of a given cylinder, for example, a given one of the cylinders 12a-12f. Misfire detection logic 220 is configured to receive as input or otherwise access a plurality of inputs 201 including crank angle parameter 202, exhaust manifold pressure (EMP) parameter 204, engine speed parameter 212, engine fueling parameter 214, and EGR parameter 216.

[0031] In the illustrated example, crank angle parameter 202, is configured and provided in form of a tooth value indicative of crank angle sensor tooth or tooth count which may be sensed and provided by a crank angle position sensor. In other embodiments, the crank angle parameter 202 may comprise other metrics of crank angle and may be denominated in terms or angle, radians, percentages, indices or other metrics as will occur to one of skill in the art with the benefit and insight of the present disclosure.

[0032] In the illustrated example, EMP parameter 204 is configured and provided in the form of a directly sensed pressure magnitude which may be sensed and provided by an exhaust manifold pressure sensor. In other embodiments, EMP parameter 204 may comprise other values correlated with or otherwise indicative of an exhaust manifold pressure, for example, pressure measurements of pressure sensors at other locations of an exhaust system.

[0033] In the illustrated example, engine speed parameter 212, is configured and provided in the form of a directly sensed engine speed which may be sensed and provided by an engine speed sensor. In other embodiments, engine speed parameter 212 comprise other values correlated with or otherwise indicative of an engine speed, for example, a position value that can be differentiated to determine an engine speed value, or an engine acceleration value or a higher-order derivative thereof.

[0034] In the illustrated example, engine fueling parameter 214 is configured and provided in the form of an injected fuel quantity which may be calculated or otherwise determined by one or more controls of an electronic control system and provided to or read by controls 100 generally and / or misfire detection logic 220 in particular. In other embodiments, engine fueling parameter214 may be configured and provided other forms comprising one or more parameters correlated with or otherwise indicative of engine fueling, for example, an injector on time and injection pressure, or an engine torques which may calculated or otherwise determined by one or more controls of an electronic control system and provided to or read by controls 100 generally and / or misfire detection logic 220 in particular or which may be sensed.

[0035] In the illustrated example, EGR parameter 216 is configured and provided as one of an EGR valve position parameter which may comprise a value sensed by an EGR position sensor or calculated or otherwise determined by one or more controls of an electronic control system and provided to or read by controls 100 generally and / or misfire detection logic 220 in particular, and a combustion mode parameter which may be calculated or otherwise determined by one or more controls of an electronic control system and provided to or read by controls 100 generally and misfire detection logic 220 in particular. A combustion mode parameter may comprise or may be set to any of a plurality of predetermined values corresponding to or indicative of a respective plurality of EGR fractions for a plurality of combustion modes. The plurality of EGR fractions may be comprise a fraction, index, or percentage indicative of a relative or absolute amount or quantity of recirculated gas desired or present in a combustion mixture. The plurality of combustion modes may correspond to engine operating conditions, for example, cold start modes, aftertreatment thermal management modes, altitude-related modes, engine speed-related modes, engine load or output-related modes, as well as other modes that will occur to one of skill in the art with the benefit and insight of the present disclosure.

[0036] Misfire detection logic 220 and is configured to determine and output discriminant function 252, which is also denoted as h(x), and misfire threshold 254 in response to the plurality of inputs 201 using discriminant function computation (DFC) logic 280 and parameter scheduling and threshold (SPAT) logic 230 as further described herein. Discriminant function 252 and misfire threshold 254 are provided as input to or otherwise accessed by misfire evaluation logic 270 which is configured to evaluate discriminant function 252 relative to misfire threshold 254, for example, by evaluating whether a value of discriminant function 252 exceeds (e.g. is greater than, greater than or equal to, less than, or less than or equal to) misfire threshold 254. In response to this evaluation, misfire evaluation logic 270 determines and outputs cylinder misfire parameter 122n which may have a true logical value indicating that a misfire of a given cylinder is detected or a false logical value indicating that a misfire of a given cylinder is not detected. Cylinder misfireparameter 122n may correspond to any of misfire determination parameters 122a-122f or to other misfire determination parameters.

[0037] With reference to Fig. 4, there are illustrated further aspects of controls 100 in the form of EGR parameter determination logic 160 controls which may be implemented in connection with controls 120n including, for example, in multiple instances and provided in each of cylinder misfire detectors 120a-120f. EGR parameter determination logic 160 includes parameter selection operator 210 which is configured to receive as input or otherwise access mode selection parameter 205, EGR position parameter 206, and combustion mode parameter 208. Parameter selection operator 210 is configured to select between EGR position parameter 206, and combustion mode parameter 208 in response to a logical value of mode selection parameter 205, and to output the selected input as EGR parameter 216.

[0038] EGR parameter determination logic 160 includes axis selection operator 211 which is configured to receive as input or otherwise access mode selection parameter 205, EGR position axis 207, and combustion mode axis 209. Axis selection operator 211 is configured to select between EGR position axis 207, and combustion mode axis 209 in response to a logical value of mode selection parameter 205, and to output the selected input as EGR axis 217.

[0039] With reference to Fig. 5 there are illustrated further aspects of SPAT logic 230 including EGR factor lookup 310, engine speed lookup 312, and engine fueling lookup 314. EGR factor lookup 310 is configured to receive as input or otherwise access EGR parameter 216 and EGR axis 217 and to determine and output table index 311 and EGR factor 326 in response to said inputs. Engine speed lookup 312 is configured to receive as input or otherwise access engine speed parameter 212 and engine speed axis 213 and to determine and output X index 313 and engine speed factor 322 in response to said inputs. Engine fueling lookup 314 is configured to receive as input or otherwise access engine fueling parameter 214 and engine fueling axis 215 and to determine and output Y index 315 and engine fueling factor 324 in response to said inputs.

[0040] With reference to Fig. 6 there are illustrated further aspects of SPAT logic 230 including interpolation vector determination logic 301 which is configured to receive as input or otherwise access engine speed factor 322, engine fueling factor 324, and EGR factor 326 and is further configured to determine interpolation vector 303 in response to said inputs. Interpolation vector determination logic 301 is configured to determine interpolation vector 303 using a three- dimensional lookup table comprising empirically determined values of interpolation vector 303for a plurality of combinations of input engine speed parameter 212, engine fueling parameter 214, and EGR parameter 216. In other embodiments, interpolation vector determination logic 301 may be configured to determine interpolation vector 303 using other techniques such computation or calculation based on one or more physics based models and / or one or more parameterized models. It shall likewise be appreciated that the other logic and logical operations described herein as determining a value or parameter using a lookup, a lookup table or the like may also utilize such other techniques.

[0041] With reference to Fig. 7 there are illustrated further aspects of SPAT logic 230 including vector indices and threshold determination (VITD) logic 320 which is configured to receive as input or otherwise access table index 311, X index 313, and Y index 315. VITD logic 320 is further configured to receive as input or otherwise access a plurality of vector tables 240 and a plurality of threshold tables 250. In the illustrated example, the plurality of vector tables 240 comprise a first vector table 241, a second vector table 242, and a third vector table 243, the plurality of threshold tables 250 comprise a first threshold table 251, a second threshold table 253, and a third threshold table 255. Other embodiments may comprise a different number of vector tables and / or a different number of threshold tables.

[0042] VITD logic 320 utilizes table index 311 to select one of the plurality of vector tables 240 and one of the plurality of threshold tables 250. VITD logic 320 further utilizes X index 313, and Y index 315 to determine vector indices 302 and table indices 323. Vector indices 302 comprise comer points of a three dimensional vector space between which interpolations may be performed. Table indices 323 comprise comer points of a three dimensional threshold space between which interpolations may be performed. Table indices 323 and interpolation vector 303 are provide as inputs to dot product multiplier 321 which calculates a dot product of said inputs and outputs misfire threshold 254.

[0043] With reference to Fig. 8, there are illustrated further aspects of DFC logic 280 including vector index calculation logic 330 which is configured to receive as input or otherwise access engine position parameter 328 and cylinder offset parameter 329. Engine position parameter 328 indicates an engine cycle angle, for example, an angle in a 720 degree engine cycle. Engine position parameter 328 may, for example, provide a value indicative of a crank angle sensor tooth count (e.g., a value between zero and 119 for a crank angle sensor comprising 60 teeth over a two engine revolution, 720 degree domain with six degree tooth increments). Cylinder offset parameter329 comprises a crank angle offset value (e.g., a tooth count or number) for a given cylinder with which DFC logic 280. Vector index calculation logic 330 determines an update parameter 331 and a vector index parameter 332 in response to said inputs. Vector index parameter 332 may be utilized to establish an offset for a calculation window determined by calculation window logic 335.

[0044] Vector index parameter 332 is provided as input to calculation window logic 335 which also receives as input detection start parameter 333, and detection end parameter 334. Calculation window logic 335 is configured to determine and output an enable parameter 336 which is effective to limit the window over which DFC logic 280 operates to omit calculations over crank angle ranges during which misfire cannot occur and reduce the computational burden imposed by DFC logic 280.

[0045] With reference to Fig. 9, there are illustrated further aspects of DFC logic 280 including classification vector calculation (CVC) logic 360 which is configured to receive as input or otherwise access vector library 339, vector indices 302, vector index parameter 332, interpolation vector 303. CVC logic 360 also receives enable parameter 336. Vector library 339 includes a plurality of classification vectors which have been empirically determined to provide a multidimensional vector space in which exhaust manifold pressure are correlated with or indicated as a function of engine fueling values and engine speed values for engine operating conditions.

[0046] CVC logic 360 is configured to utilize vector index parameter 332 to select a vector from vector library 339. CVC logic 360 is further configured to utilize vector indices 302 to select a comer points of the vector selected in response to vector index parameter 332. CVC logic 360 is further configured to utilize interpolation vector 303 to interpolate between the selected corner points to determine a classification vector 361 which is also denoted as (V(i).

[0047] With reference to Fig. 10, there are illustrated further aspects of DFC logic 280 and SPAT logic 230. As illustrated therein, DFC logic 280 includes dot product multiplier 340 which is configured to receive as input or otherwise access classification vector 361 and EMP parameter 204. Dot product multiplier 340 is further configured to calculate as output the dot product of these inputs to determine and provide as output discriminant function 252. As also illustrated therein, VITD Logic 320 of SPAT logic 230 is configured to receive as input or otherwise access update parameter 331 which is utilized to trigger VITD Logic 320 to determine updated values of vector indices 302 and misfire threshold 254.

[0048] With reference to Fig. 1 1, there are illustrated controls 500 which may be implemented in and operated by one or more components of an electronic control system such as controller 42 and / or other components of ECS 23 or another electronic control system. Controls 500 are configured and operable to detect consecutive misfire events for a plurality of pairs of sequentially firing cylinders of an engine. It shall be appreciated that consecutive misfire events comprise events wherein a consecutive pair of cylinders according to a predetermined firing order or sequence both misfire.

[0049] Controls 500 may operate in parallel with or concurrently with controls 100. Controls 500 may be utilize to distinguish exhaust manifold pressure characteristics resulting from consecutively misfiring cylinders, from exhaust manifold pressure characteristics resulting from each of: misfire of only the first one of a pair of consecutively firing cylinders, misfire of only the second one of the pair of consecutively firing cylinders, and non-misfire operation of both of the first one and the second one of the pair of consecutively firing cylinders.

[0050] In the illustrated example, controls 500 are configured and operable to detect misfire of cylinders 12a-12f of engine 12 which is configured with a firing sequence or order of cylinder nos. 1, 5, 3, 6, 2, 4. In other embodiments, controls 100 may be configured and operable to detect misfire of different numbers of cylinders of other engines.

[0051] Controls 500 include consecutive cylinder misfire detectors 520a-520f which are configured and operable to separately detect misfire of respective pairs of cylinders 12a-12f. In other words, consecutive cylinder detector 520a is configured and operable to detect misfire of cylinder 12a, consecutive cylinder detector 520b is configured and operable to detect misfire of cylinder 12b, consecutive cylinder detector 520c is configured and operable to detect misfire of cylinder 12c, and so forth through to and including consecutive cylinder detector 520f and cylinder 12f.

[0052] Consecutive cylinder misfire detectors 520a-520f are configured and operable to output respective ones of consecutive misfire determination parameters 522a-522f which correspond to respective ones of cylinders 12a-12f. In other words, consecutive cylinder detector 520a is configured and operable to output misfire determination parameter 522a corresponding to cylinder 12a, consecutive cylinder detector 520b is configured and operable to detect misfire of cylinder 12b, consecutive cylinder detector 520c is configured and operable to detect misfire of cylinder12c, and so forth through to and including consecutive cylinder detector 520f, misfire determination parameter 522f, and cylinder 12f.

[0053] Consecutive cylinder misfire detectors 520a-520f are configured and operable to receive a plurality of engine operating parameters 502 during operation of an associated engine system. Engine operating parameters 502 engine operating parameters 502 may be the same as, similar to or different from engine operating parameters 502. Engine operating parameters 502 may be based upon outputs from a plurality of sensors, for example, an engine speed sensor, an EGR valve position sensor, and an exhaust manifold pressure sensors. Engine operating parameters 502 may be based upon control parameters determined by an electronic control system, for example, an engine fueling control parameter, and an EGR valve position control parameter. Consecutive cylinder misfire detectors 520a-520f are further configured and operable to receive calibration parameters 512 which may be received and stored during calibration of an associated engine system and thereafter accessed or utilized by consecutive cylinder misfire detectors 520a- 520f.

[0054] With reference to Fig. 12, there are illustrated further aspects of controls 500 in the form of controls 520n which may be implemented in multiple instances and provided in each of consecutive cylinder misfire detectors 520a-520f. It shall be appreciated that controls 500 and controls 520n may include and utilize certain aspects and parameters described in connection with controls 100 and controls 120n. Such aspects are denoted with like reference numerals and the related description of controls 100 and controls 120n applies, mutatis mutandis, to controls 500 and controls 520n.

[0055] Controls 520n include misfire detection logic 220 which may be configured and implemented to detect misfire of a given pair of consecutively firing cylinder, for example, cylinder nos. 1 and 5 of the cylinders 12a-12f. Misfire detection logic 520 is configured to receive as input or otherwise access a plurality of inputs 201 including crank angle parameter 202, exhaust manifold pressure (EMP) parameter 204, engine speed parameter 212, engine fueling parameter 214, and EGR parameter 216 which are further described herein in connection with Fig. 3.

[0056] Misfire detection logic 520 and is configured to determine and output discriminant function 252 and misfire threshold 254, discriminant function 562 and misfire threshold 564, and discriminant function 57.2 and misfire threshold 574 in response to the plurality of inputs 201 using discriminant function computation (DFC) logic (which may be of the same or substantiallysimilar type as DFC logic 280 described above in connection with Fig. 3), and parameter scheduling and threshold (SPAT) logic (which may be of the same or substantially similar type as described above in connection with Fig. 3). Discriminant function 552 and misfire threshold 554 may be configured and operable to distinguish a consecutive misfire event wherein cylinder nos. 1 and 5 misfire consecutively from a misfire event wherein only cylinder no. 1 misfires. Discriminant function 562 and misfire threshold 564 may be configured and operable to distinguish a consecutive misfire event wherein cylinder nos. 1 and 5 misfire consecutively from a misfire event wherein only cylinder no. 5 misfires. Discriminant function 572 and misfire threshold 574 may be configured and operable to distinguish a consecutive misfire event wherein cylinder nos. 1 and 5 misfire consecutively from a non-misfire event wherein only neither of cylinder nos. 1 and 5 misfires.

[0057] Discriminant function 552 and misfire threshold 554, discriminant function 562 and misfire threshold 564, and discriminant function 572 and misfire threshold 574 are provided as input to or otherwise accessed by misfire evaluation logic 570 which is configured to evaluate discriminant function 552 relative to misfire threshold 554, evaluate discriminant function 562 relative to misfire threshold 564, and evaluate discriminant function 572 relative to misfire threshold 574. Such evaluation may be of the same or substantially similar type as the evaluation performed by misfire evaluation logic 270 described in connection with Fig. 3. Misfire evaluation logic 570 determines and outputs cylinder misfire parameter 522n which may have a true logical value indicating that a consecutive misfire of a given consecutively firing pair of cylinders is detected or a false logical value indicating that such a consecutive misfire is not detected. Cylinder misfire parameter 522n may correspond to any of consecutive misfire determination parameters 522a-522f or to other misfire determination parameters. Misfire evaluation logic 270 may output true if and only if each of the evaluation of discriminant function 552 relative to misfire threshold 554, the evaluation of discriminant function 562 relative to misfire threshold 564, and the evaluation of discriminant function 572 relative to misfire threshold 574 indicates a consecutive misfire event. Such operation may distinguish from misfire of only the first one of a pair of consecutively firing cylinders, misfire of only the second one of the pair of consecutively firing cylinders, and non-misfire operation of both of the first one and the second one of the pair of consecutively firing cylinders.

[0058] With reference to Fig. 13, there are illustrated aspects of DFC logic 680 which may be provided and utilized as the DFC logic of. DFC logic 680 includes classification vector calculation (CVC) logic 660 which is configured to receive as input or otherwise access vector library 639, vector library 649, vector library 659, vector indices 302, vector index parameter 332, and interpolation vector 303. CVC logic 360 also receives enable parameter 336. Each of vector library 639, vector library 649, and vector library 659 includes a plurality of classification vectors which have been empirically determined to provide a multi-dimensional vector space in which exhaust manifold pressure are correlated with or indicated as a function of engine fueling values and engine speed values for engine operating conditions. Vector library 639 may include a plurality of classification vectors suitable for distinguishing a consecutive misfire event from a misfire of only the first one of a pair of consecutively firing cylinders. Vector library 649 may include a plurality of classification vectors suitable for distinguishing a consecutive misfire event from a misfire of only the second one of the pair of consecutively firing cylinders. Vector library 659 may include a plurality of classification vectors suitable for distinguishing a consecutive misfire event from a non-misfire operation of both of the first one and the second one of the pair of consecutively firing cylinders.

[0059] CVC logic 660 is configured to utilize vector index parameter 332 to select a vector from vector library 339. CVC logic 360 is further configured to utilize vector indices 302 to select a comer points of the vector selected in response to vector index parameter 332. CVC logic 660 is further configured to utilize interpolation vector 303 to interpolate between the selected corner points to determine classification vector 661, classification vector 662, and classification vector 663.

[0060] As shown by this detailed description, the present disclosure contemplates multiple and various embodiments, including, without limitation, the following example embodiments.

[0061] A first example embodiment is a system comprising: an internal combustion engine including a plurality of cylinders; and an electronic control system operatively coupled with the internal combustion engine and configured to: store a vector library comprising a plurality of classification vectors empirically determined for a plurality of engine operating conditions, receive a plurality of engine operating parameters including an engine speed parameter, an engine fueling parameter, an EGR parameter, a crank angle parameter, and an exhaust manifold pressure parameter, determine a interpolation vector in response to the engine speed parameter, the enginefueling parameter, and the EGR parameter, determine a classification vector in response to the vector library, the crank angle parameter and the interpolation vector, determine a discriminant function in response to the exhaust manifold pressure parameter and the classification vector, determine a misfire threshold in response to the engine speed parameter, the engine fueling parameter, and the EGR parameter, and detect a cylinder misfire in response to the misfire threshold and the discriminant function parameter.

[0062] A second example embodiment includes the features of the first example embodiment, wherein the electronic control system being configured to determine the interpolation vector comprises the electronic control system being configured to provide the engine speed parameter, the engine fueling parameter, and the EGR parameter as inputs to a table comprising empirically determined values of the interpolation vector for a plurality of values of the engine speed parameter, the engine fueling parameter, and the EGR parameter.

[0063] A third example embodiment includes the features of the first example embodiment, wherein the electronic control system being configured to determine the classification vector comprises the electronic control system being configured to: select a classification vector of a vector library comprising a plurality of classification vectors in repose to the crank angle parameter, determine a set of vector indices, select a plurality of corner points of the classification vector in response to the set of vector indices, and determine an interpolated classification vector in response to the plurality of corner points and the interpolation vector.

[0064] A fourth example embodiment includes the features of the third example embodiment, wherein the electronic control system being configured to determine the set of vector indices comprises the electronic control system being configured to: select a vector table from a plurality of vector tables in response to the EGR parameter, and determine the set of vector indices in response to the vector table, the engine speed parameter, and the engine fueling parameter.

[0065] A fifth example embodiment includes the features of the first example embodiment, wherein the electronic control system being configured to determine the discriminant function comprises the electronic control system being configured to calculate the discriminant function as a dot product of the exhaust manifold pressure parameter and the classification vector.

[0066] A sixth example embodiment includes the features of the first example embodiment, wherein the electronic control system being configured to determine the misfire thresholdcomprises the electronic control system being configured to: determine a set of table indices, and determine the misfire threshold in response to the set of table indices and the interpolation vector.

[0067] A seventh example embodiment includes the features of the sixth example embodiment, wherein the electronic control system being configured to determine the set of table indices comprises the electronic control system being configured to: select a threshold table from a plurality of threshold tables in response to the EGR parameter, and determine the set of vector indices in response to the threshold table, the engine speed parameter, and the engine fueling parameter.

[0068] An eighth example embodiment includes the features of the first example embodiment, wherein the electronic control system operatively configured to identify a consecutive misfire event comprising misfire of both of a pair of consecutively firing cylinders.

[0069] A ninth example embodiment is a process of operating an electronic control system operatively coupled with an internal combustion engine including a plurality of cylinders, the process comprising: storing a vector library comprising a plurality of classification vectors empirically determined for a plurality of engine operating conditions, receiving a plurality of engine operating parameters including an engine speed parameter, an engine fueling parameter, an EGR parameter, a crank angle parameter, and an exhaust manifold pressure parameter, determining a interpolation vector in response to the engine speed parameter, the engine fueling parameter, and the EGR parameter, determining a classification vector in response to the vector library, the crank angle parameter and the interpolation vector, determining a discriminant function in response to the exhaust manifold pressure parameter and the classification vector, determining a misfire threshold in response to the engine speed parameter, the engine fueling parameter, and the EGR parameter, and detecting a cylinder misfire in response to the misfire threshold and the discriminant function parameter.

[0070] A tenth example embodiment includes the features of the ninth example embodiment, wherein the determining the interpolation vector comprises providing the engine speed parameter, the engine fueling parameter, and the EGR parameter as inputs to a table comprising empirically determined values of the interpolation vector for a plurality of values of the engine speed parameter, the engine fueling parameter, and the EGR parameter.

[0071] An eleventh example embodiment includes the features of the ninth example embodiment, wherein the determining the classification vector comprises: selecting aclassification vector of a vector library comprising a plurality of classification vectors in repose to the crank angle parameter, determining a set of vector indices, selecting a plurality of corner points of the classification vector in response to the set of vector indices, and determining an interpolated classification vector in response to the plurality of comer points and the interpolation vector.

[0072] A twelfth example embodiment includes the features of the eleventh example embodiment, wherein the determining the set of vector indices comprises: selecting a vector table from a plurality of vector tables in response to the EGR parameter, and determining the set of vector indices in response to the vector table, the engine speed parameter, and the engine fueling parameter.

[0073] A thirteenth example embodiment includes the features of the ninth example embodiment, wherein the determining the discriminant function comprises calculating the discriminant function as a dot product of the exhaust manifold pressure parameter and the classification vector.

[0074] A fourteenth example embodiment includes the features of the ninth example embodiment, wherein the determining the misfire threshold comprises: determining a set of table indices, and determining the misfire threshold in response to the set of table indices and the interpolation vector.

[0075] A fifteenth example embodiment includes the features of the fourteenth example embodiment, wherein the determining the set of table indices comprises: selecting a threshold table from a plurality of threshold tables in response to the EGR parameter, and determining the set of vector indices in response to the threshold table, the engine speed parameter, and the engine fueling parameter.

[0076] A sixteenth example embodiment includes the features of the ninth example embodiment, comprising identifying a consecutive misfire event comprising misfire of both of a pair of consecutively firing cylinders.

[0077] It shall be appreciated that terms such as “a non-transitory memory,” “a non-transitory memory medium,” and “a non-transitory memory device” refer to a number of types of devices and storage mediums which may be configured to store information, such as data or instructions, readable or executable by a processor or other components of a computer system and that such terms include and encompass a single or unitary device or medium storing such information, multiple devices or media across or among which respective portions of such information arestored, and multiple devices or media across or among which multiple copies of such information are stored.

[0078] It shall be appreciated that terms such as “determine,” “determined,” “determining” and the like when utilized in connection with a control method or process, an electronic control system or controller, electronic controls, or components or operations of the foregoing refer inclusively to a number of acts, configurations, devices, operations, and techniques including, without limitation, calculation or computation of a parameter or value, obtaining a parameter or value from a lookup table or using a lookup operation, receiving parameters or values from a datalink or network communication, receiving an electronic signal (e.g., a voltage, frequency, current, or pulse-width modulation (PWM) signal) indicative of the parameter or value, receiving output of a sensor indicative of the parameter or value, receiving other outputs or inputs indicative of the parameter or value, reading the parameter or value from a memory location on a computer- readable medium, receiving the parameter or value as a run-time parameter, and / or by receiving a parameter or value by which the interpreted parameter can be calculated, and / or by referencing a default value that is interpreted to be the parameter value.

[0079] While example embodiments of the disclosure have been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only certain example embodiments have been shown and described and that all changes and modifications that come within the spirit of the claimed inventions are desired to be protected. It should be understood that while the use of words such as preferable, preferably, preferred or more preferred utilized in the description above indicates that the feature so described may be more desirable, it nonetheless may not be necessary and embodiments lacking the same may be contemplated as within the scope of the invention, the 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,” or “at least one portion” are used there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. When the language “at least a portion” and / or “a portion” is used the item can include a portion and / or the entire item unless specifically stated to the contrary.

Claims

CLAIMS1. A system comprising: an internal combustion engine including a plurality of cylinders; and an electronic control system operatively coupled with the internal combustion engine and configured to: store a vector library comprising a plurality of classification vectors empirically determined for a plurality of engine operating conditions, receive a plurality of engine operating parameters including an engine speed parameter, an engine fueling parameter, an EGR parameter, a crank angle parameter, and an exhaust manifold pressure parameter, determine a interpolation vector in response to the engine speed parameter, the engine fueling parameter, and the EGR parameter, determine a classification vector in response to the vector library, the crank angle parameter and the interpolation vector, determine a discriminant function in response to the exhaust manifold pressure parameter and the classification vector, determine a misfire threshold in response to the engine speed parameter, the engine fueling parameter, and the EGR parameter, and detect a cylinder misfire in response to the misfire threshold and the discriminant function parameter.

2. The system of claim 1, wherein the electronic control system being configured to determine the interpolation vector comprises the electronic control system being configured to provide the engine speed parameter, the engine fueling parameter, and the EGR parameter as inputs to a table comprising empirically determined values of the interpolation vector for a plurality of values of the engine speed parameter, the engine fueling parameter, and the EGR parameter.

3. The system of claim 1 , wherein the electronic control system being configured to determine the classification vector comprises the electronic control system being configured to: select a classification vector of a vector library comprising a plurality of classificationvectors in repose to the crank angle parameter, determine a set of vector indices, select a plurality of comer points of the classification vector in response to the set of vector indices, and determine an interpolated classification vector in response to the plurality of comer points and the interpolation vector.

4. The system of claim 3, wherein the electronic control system being configured to determine the set of vector indices comprises the electronic control system being configured to: select a vector table from a plurality of vector tables in response to the EGR parameter, and determine the set of vector indices in response to the vector table, the engine speed parameter, and the engine fueling parameter.

5. The system of claim 1, wherein the electronic control system being configured to determine the discriminant function comprises the electronic control system being configured to calculate the discriminant function as a dot product of the exhaust manifold pressure parameter and the classification vector.

6. The system of claim 1, wherein the electronic control system being configured to determine the misfire threshold comprises the electronic control system being configured to: determine a set of table indices, and determine the misfire threshold in response to the set of table indices and the interpolation vector.

7. The system of claim 6, wherein the electronic control system being configured to determine the set of table indices comprises the electronic control system being configured to: select a threshold table from a plurality of threshold tables in response to the EGR parameter, and determine the set of vector indices in response to the threshold table, the engine speed parameter, and the engine fueling parameter.

8. The system of claim 1, wherein the electronic control system operatively configured to identify a consecutive misfire event comprising misfire of both of a pair of consecutively firing cylinders.

9. A process of operating an electronic control system operatively coupled with an internal combustion engine including a plurality of cylinders, the process comprising: storing a vector library comprising a plurality of classification vectors empirically determined for a plurality of engine operating conditions, receiving a plurality of engine operating parameters including an engine speed parameter, an engine fueling parameter, an EGR parameter, a crank angle parameter, and an exhaust manifold pressure parameter, determining a interpolation vector in response to the engine speed parameter, the engine fueling parameter, and the EGR parameter, determining a classification vector in response to the vector library, the crank angle parameter and the interpolation vector, determining a discriminant function in response to the exhaust manifold pressure parameter and the classification vector, determining a misfire threshold in response to the engine speed parameter, the engine fueling parameter, and the EGR parameter, and detecting a cylinder misfire in response to the misfire threshold and the discriminant function parameter.

10. The process of claim 9, wherein the determining the interpolation vector comprises providing the engine speed parameter, the engine fueling parameter, and the EGR parameter as inputs to a table comprising empirically determined values of the interpolation vector for a plurality of values of the engine speed parameter, the engine fueling parameter, and the EGR parameter.

11. The process of claim 9, wherein the determining the classification vector comprises: selecting a classification vector of a vector library comprising a plurality of classification vectors in repose to the crank angle parameter,determining a set of vector indices, selecting a plurality of comer points of the classification vector in response to the set of vector indices, and determining an interpolated classification vector in response to the plurality of comer points and the interpolation vector.

12. The process of claim 11, wherein the determining the set of vector indices comprises: selecting a vector table from a plurality of vector tables in response to the EGR parameter, and determining the set of vector indices in response to the vector table, the engine speed parameter, and the engine fueling parameter.

13. The process of claim 9, wherein the determining the discriminant function comprises calculating the discriminant function as a dot product of the exhaust manifold pressure parameter and the classification vector.

14. The process of claim 9, wherein the determining the misfire threshold comprises: determining a set of table indices, and determining the misfire threshold in response to the set of table indices and the interpolation vector.

15. The process of claim 14, wherein the determining the set of table indices comprises: selecting a threshold table from a plurality of threshold tables in response to the EGR parameter, and determining the set of vector indices in response to the threshold table, the engine speed parameter, and the engine fueling parameter.

16. The process of claim 9, comprising identifying a consecutive misfire event comprising misfire of both of a pair of consecutively firing cylinders.

17. An apparatus for controlling operation of an internal combustion engine including aplurality of cylinders, the apparatus comprising: an electronic controller configured to: store a vector library comprising a plurality of classification vectors empirically determined for a plurality of engine operating conditions, receive a plurality of engine operating parameters including an engine speed parameter, an engine fueling parameter, an EGR parameter, a crank angle parameter, and an exhaust manifold pressure parameter, determine a interpolation vector in response to the engine speed parameter, the engine fueling parameter, and the EGR parameter, determine a classification vector in response to the vector library, the crank angle parameter and the interpolation vector, determine a discriminant function in response to the exhaust manifold pressure parameter and the classification vector, determine a misfire threshold in response to the engine speed parameter, the engine fueling parameter, and the EGR parameter, and detect a cylinder misfire in response to the misfire threshold and the discriminant function parameter.

18. The system of claim 17, wherein the electronic controller being configured to determine the interpolation vector comprises the electronic controller being configured to provide the engine speed parameter, the engine fueling parameter, and the EGR parameter as inputs to a table comprising empirically determined values of the interpolation vector for a plurality of values of the engine speed parameter, the engine fueling parameter, and the EGR parameter.

19. The system of claim 17, wherein the electronic controller being configured to determine the classification vector comprises the electronic controller being configured to: select a classification vector of a vector library comprising a plurality of classification vectors in repose to the crank angle parameter, determine a set of vector indices, select a plurality of comer points of the classification vector in response to the set of vector indices, anddetermine an interpolated classification vector in response to the plurality of comer points and the interpolation vector.

20. The system of claim 19, wherein the electronic controller being configured to determine the set of vector indices comprises the electronic controller being configured to: select a vector table from a plurality of vector tables in response to the EGR parameter, and determine the set of vector indices in response to the vector table, the engine speed parameter, and the engine fueling parameter.

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