Apparatus, method, system, and techniques for misfire detection using an engine speed sensor

Abstract

A system includes a reciprocating piston engine configured to output torque to drive a load. The system includes an engine speed sensor operatively coupled with the engine and configured to output an engine speed signal. The system includes an electronic control system operatively coupled with the powertrain. The electronic control system is configured to determine an engine acceleration in response to the engine speed signal, and to detect a misfire of the engine in response to the engine acceleration.

Description

Technical Field

[0001] This application relates to the control of reciprocating piston engines and to equipment, methods, systems and techniques for misfire detection using engine speed sensors. Background Technology

[0002] Reciprocating piston internal engines can encounter numerous faults, such as injector malfunction, valve misalignment, valve sticking, or compression failure. These faults can lead to cylinder misfires and a lack of power or inappropriate power output. Due to such faults, the engine may suffer performance losses, repair costs, and downtime due to progressive damage. Additionally, such faults can cause the engine to fail to meet emission limits, potentially delegating restrictions regarding the occurrence of misfires and / or the emissions produced. Many recommendations have been proposed for detecting engine misfires. Existing recommendations have several drawbacks and limitations. For example, some proposals require the use of multiple sensors, such as exhaust manifold pressure sensors, exhaust manifold temperature sensors, and / or accelerometers. Existing recommendations also fail to pinpoint the cause of the misfire detection, requiring service technicians to correlate multiple data points to resolve the issue and determine appropriate corrective actions. Existing recommendations may also require steady-state operation or specific operating procedures that interfere with otherwise expected engine operation for misfire detection. Existing recommendations are also not accurate enough to provide online process correction during transient operations. Existing recommendations, such as misfire detection based on exhaust manifold pressure, have low fidelity in low-speed, low-load regions, sometimes requiring multiple sensors, and can also be negatively affected by air handling noise factors such as thermal management events, exhaust gas recirculation, and altitude changes.

[0003] Public content of example implementation plan

[0004] To clearly, concisely, and accurately describe the exemplary embodiments of this disclosure, the manner and process of making and using this disclosure, and to enable the practice, making, and use of this disclosure, reference will now be made to certain exemplary embodiments, including those shown in the figures, and specific language will be used to describe this disclosure. However, it should be understood that this does not constitute any limitation on the scope of the invention, and that the invention includes and protects such changes, modifications, and further applications of the exemplary embodiments as would be conceived by those skilled in the art. Summary of the Invention

[0005] Example implementations include unique devices, methods, systems, and techniques for detecting misfire events in reciprocating internal combustion engines using an engine crankshaft speed sensor. Further implementations, forms, objectives, features, advantages, aspects, and benefits will become apparent from the following description and figures. Attached Figure Description

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

[0007] Figures 2A to 2C This is a flowchart illustrating certain aspects of example engine diagnostics.

[0008] Figures 2D to 2E This is a flowchart illustrating certain aspects of another form of example engine diagnostics.

[0009] Figure 3 This is a schematic diagram illustrating certain aspects of example engine health prognostics.

[0010] Figures 4A to 4C This is a diagram illustrating certain aspects of example fire detection techniques.

[0011] Figure 5 This is a diagram illustrating certain aspects of example fire detection techniques.

[0012] Figure 6 This is a diagram illustrating certain aspects of example fire detection techniques. Detailed Implementation

[0013] refer to Figure 1 The figure illustrates 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, which includes an intake manifold 14 fluidly connected via an intake duct 20 to the outlet of a compressor 16 of a turbocharger 18. The compressor 16 includes a compressor inlet connected to an intake duct 22 for receiving fresh air from the intake duct. The compressor 16 is mechanically connected to a turbine 26 via a drive shaft 28. The turbine 26 includes a turbine inlet fluidly connected via an exhaust duct 32 to an exhaust manifold 30 of the engine 12. System 10 may include an intake air cooler 24 disposed in line with the intake duct 20 between the compressor 16 and the intake manifold 14. System 10 may also include an intake throttle valve (IAT) 21. In other embodiments, engine 10 may be naturally aspirated and turbocharger 18 may be omitted. In another embodiment, the engine 10 may be turbocharged and may be provided with one or more engine-driven compressors instead of exhaust gas driven turbochargers 18.

[0014] In the illustrated embodiment, engine 12 is a reciprocating piston, direct injection, compression ignition engine configured to burn diesel fuel. However, it should be understood that engine 12 may also be provided in other forms, including one or more of port injection and spark ignition, and configured to burn other types of fuels, such as natural gas or other gaseous fuels or gasoline. It should be further understood that the teachings of this disclosure can be implemented in conjunction with substantially any reciprocating piston engine.

[0015] Engine 12 includes a plurality of cylinders 12a to 12f, each containing a corresponding reciprocating piston. Each reciprocating piston is connected to a crankshaft via a corresponding connecting rod (not shown) to reciprocate within the corresponding cylinder 12a to 12f in a standard manner for four-stroke engine operation. Each cylinder 12a to 12f includes a combustion chamber having appropriate intake and exhaust valves (not shown) and fuel injectors 13a to 13f. Fuel injectors 13a to 13f are configured to operate in response to signals from an electronic controller (such as those further described herein). Fuel injectors 13a to 13f receive fuel from a fuel source (not shown) in fluid communication with them.

[0016] System 10 includes an EGR valve 38 arranged in a straight line with EGR pipe 36, one end of which is fluidly connected to intake pipe 20, and the other end is fluidly connected to exhaust pipe 32. Figure 1 As shown by the dashed line, the EGR cooler 40 can optionally be arranged in a straight line with the EGR pipe 36 between the EGR valve 38 and the intake pipe 20.

[0017] System 10 includes an electronic control system. In the illustrated form, the electronic control system includes a controller 42, which may be provided as an electronic control unit (ECU) or an electronic control module (ECM). The electronic control system may also include additional controllers, which may be provided as additional ECU or ECM units, communicating with each other via a communication network such as a controller area network (CAN). In some embodiments, one or more parts or components of the electronic control system, such as controller 42, may be provided in the form of an electronic computing system for a diagnostic device configured to be operatively coupled to the engine. In some such embodiments, controller 42 or other electronic computing system components may receive information, such as signals that allow controller 42 or other electronic computing system components to evaluate or determine one or more additional signals associated with the cylinder combustion sequence of the engine being diagnosed or otherwise evaluated. Such information may include, for example, a signal from a crank "reference" marker sensor indicating an angle (e.g., corresponding to top dead center (TDC), bottom dead center (BDC), or another angle for a given cylinder). Providing such information to controller 42 or other electronic computing system components may include the translation or conversion of one or more signals to achieve or facilitate the aforementioned actions and capabilities.

[0018] Controller 42 is generally operable to control and manage operational aspects of engine 12. Controller 42 includes memory 45 and multiple inputs and outputs for interfacing with various sensors and systems coupled to engine 12. Controller 42 can be an electronic circuit consisting of one or more components, including digital circuitry, analog circuitry, or both. Controller 42 can be of the software and / or firmware programmable type; a hard-wired dedicated state machine; or a combination of these. In one embodiment, controller 42 is of the programmable microcontroller solid-state integrated circuit type, including memory 45 and one or more central processing units. Memory 45 can consist of one or more components and can be of any volatile or non-volatile type, including solid-state, optical, magnetic, combinations of these, or other arrangements. Controller 42 may include, as needed, signal conditioners, signal format converters (e.g., analog-to-digital converters and digital-to-analog converters), limiters, clampers, filters, etc., to perform the various control and regulation operations described herein.

[0019] Controller 42 can be configured to regulate and control the overall operation of engine 12. Alternatively, controller 42 can be configured to regulate and control a set of controlled aspects of engine 12. Controller 42 is configured to store controller-executable instructions and execute these instructions to provide regulation and control of engine 12. These controller-executable instructions can be configured according to one or more control processes described herein, as well as other control processes.

[0020] The controller 42 is configured to receive multiple inputs for receiving signals from various sensors or sensing systems associated with the system 10. For example, the system 10 includes an engine speed sensor 44 electrically connected to the engine speed input ES of the controller 42 via a signal path 46. The engine speed sensor 44 is operable to sense the rotational speed of the engine 12 and generate an engine speed signal indicating the engine speed on the signal path 46. The engine speed sensor 44 may be configured as a crankshaft speed sensor. In one embodiment, the engine speed sensor 44 is a Hall effect sensor operable to determine the engine speed. Alternatively, the engine speed sensor 44 may be any other known sensor operable as described above, including but not limited to variable magnetoresistive sensors, etc. The system 10 also includes a fuel system sensor 47 electrically connected to the fuel system input FS of the controller 42 via a signal path 71. In the illustrated embodiment, the fuel system sensor 47 is configured as a rail pressure sensor, which is configured to sense the pressure associated with the fuel rails 49 configured to supply fuel to fuel injectors 13a to 13f.

[0021] System 10 may include an intake manifold temperature sensor 48, which is configured to be in fluid communication with the intake manifold 14 of engine 12 and electrically connected to the intake manifold temperature input (IMT) of controller 42 via signal path 50. The intake manifold temperature sensor 48 is operable to provide a temperature signal on signal path 50 indicating the temperature of the charge air flowing into the intake manifold 14, wherein the charge air flowing into the intake manifold 14 typically consists of fresh air supplied by turbocharger compressor 16 combined with recirculated exhaust gas supplied via EGR valve 38.

[0022] System 10 may further include an intake manifold pressure sensor 52, which is configured to be in fluid communication with the intake manifold 14 and electrically connected to the intake manifold pressure input (IMP) of the controller 42 via a signal path 54. Alternatively, the pressure sensor 52 may be configured to be in fluid communication with the intake duct 20. In either case, the pressure sensor 52 is operable to generate a pressure signal on the signal path 54 indicating the air pressure within the intake duct 20 and the intake manifold 14.

[0023] System 10 may also include an exhaust manifold pressure sensor 72, which is configured to be in fluid communication with exhaust manifold 30 and electrically connected to the exhaust manifold pressure input (EMP) of controller 42 via signal path 72a. In other forms, pressure sensor 72 may be configured to be in fluid communication with exhaust pipe 32. Pressure sensor 72 is operable to generate a pressure signal on signal path 72 indicating the gas pressure within exhaust pipe 32 and exhaust manifold 30. In other forms, one or both of exhaust manifold pressure sensor 72 and exhaust manifold temperature sensor 74 may not be present in system 10, and exhaust pressure and temperature may be calculated or estimated based on other parameters. For example, in the form where exhaust manifold pressure sensor is absent, many techniques or models can be used to calculate or estimate exhaust manifold pressure, such as via velocity density equations or through other calculations or estimations.

[0024] System 10 may include a differential pressure sensor or a DP sensor 56, one end of which is fluidly connected via conduit 60 to an EGR conduit 36 ​​adjacent to the exhaust gas inlet of EGR valve 38, and the other end of which is fluidly connected via conduit 58 to an EGR conduit 36 ​​adjacent to the exhaust gas outlet of EGR valve 38. Alternatively, the DP sensor 56 may be connected across another flow-limiting mechanism arranged in a straight line with EGR conduit 36. In either case, the DP sensor 56 may have a known configuration and be electrically connected via signal path 62 to the DP input of controller 42. The DP sensor 56 is operable to provide a differential pressure signal on signal path 62, indicating the pressure difference across EGR valve 38 or another flow-limiting mechanism arranged in a straight line with EGR conduit 36. Nevertheless, it should be appreciated that in other embodiments, EGR valve 38, DP sensor 56, and associated conduits, coolers, etc., may be absent.

[0025] 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, the EGR valve 38 is electrically connected to the EGR valve output (EGRV) of the controller 42 via signal path 64. As is known in the art, the controller 42 is operable to generate an EGR valve control signal on signal path 64, thereby correspondingly controlling the position of the EGR valve 38 relative to a reference position in a known manner. The controller 42 is thus operable to control the EGR valve 38 to selectively supply recirculated exhaust gas flow from exhaust manifold 30 to intake manifold 14. Thus, although the gas composition flowing along passage 33 changes from (a) compressed air, (b) air / fuel filler, and then (c) exhaust gas when the EGR valve 38 is closed, this composition may also include various large quantities of recirculated exhaust gas when the EGR valve 38 is open. In some embodiments, the controller 42 may also include one or more outputs for controlling the operation of turbocharger mechanisms, such as a variable geometry actuator (if present) for the exhaust valve of turbocharger 18.

[0026] Controller 42 is also configured to provide multiple refueling command outputs, said outputs for controlling the operation of each fuel injector 13a to 13f or for supplying to another number of fuel injectors present in other embodiments and forms of system 10. The signal path for the FC output is also... Figure 1 The reference numeral 70 is used to denote the fuel injection; however, it should be understood that the timing of fuel injection by each injector 13a to 13f can be independently controlled by controller 42. In addition to the timing of fuel injection, controller 42 can also adjust the fuel injection quantity. Typically, the fuel quantity varies with the number and duration of injector activation pulses supplied to injectors 13a to 13f.

[0027] System 10 may also include an aftertreatment system 80 that provides aftertreatment of exhaust gases before they are emitted through duct 94. During engine operation, exhaust gases flow from turbine outlet 27 through exhaust duct 34, which is in fluid communication with turbine outlet 27. Duct 34 is also in fluid communication with aftertreatment system 80, which receives exhaust gases from turbine 26 for aftertreatment. Aftertreatment system 80 may include a variety of catalysts configured to chemically convert and / or remove unwanted components from the exhaust gas stream before emission into the environment. In the illustrated form, aftertreatment system 80 includes a diesel particulate filter (DPF) 84 configured to reduce particulate emissions. Aftertreatment system 80 in the illustrated form also includes a selective catalytic reduction (SCR) catalyst 86 configured to catalyze the reduction of nitrogen oxides (NOx) by incorporating a reducing agent, for example, a diesel exhaust fluid (DEF) introduced into the exhaust gas stream via a meter or injector (not shown) upstream of the SCR catalyst 86. In other embodiments, the aftertreatment system 80 may include additional or alternative catalysts, including, for example, oxidation catalysts and ammonia leakage catalysts, as well as other catalysts that would be conceived by those skilled in the art in light of this disclosure.

[0028] For nominal operation, the temperature of one or more parts of the aftertreatment system 80 may need to meet certain temperature conditions. For example, the SCR catalyst 84 may need to reach a minimum temperature to operate as expected or desired. Additionally, for some regeneration modes, higher temperatures are sometimes required. For example, the DPF 84 may require elevated temperatures for periodic regeneration to remove accumulated particulate matter.

[0029] System 10 is configured to drive load 79. In some embodiments, system 10 may be configured to propel a vehicle, and load L may be a propulsive load applied to a drivetrain operatively coupled to system 10, including, for example, a number of load components such as aerodynamic drag, rolling drag, and grade / gravity drag. The drivetrain operatively coupled to system 10 may include, for example, a transmission, drive shaft, differential, and drive wheels. In some embodiments, load 79 may be a generator, and system 10 may be configured as a generator set. In other embodiments, load L may include a pump, compressor, or another type of load, as will be apparent to those skilled in the art benefiting from this disclosure.

[0030] refer to Figures 2A to 2C The figure illustrates certain aspects of an example engine misfire diagnostic process 200, which can be implemented and executed in conjunction with one or more components of an electronic control system associated with the engine system, such as... Figure 1 The controller 42 of the described system 10, or one or more alternative or additional components of the electronic control system.

[0031] After being initiated, process 200 proceeds to operation 202, which evaluates whether the engine speed (e.g., the engine speed signal received from an engine speed sensor) meets a minimum threshold condition. If the engine speed does not meet the minimum threshold condition, process 200 may repeat operation 202, or it may terminate and start or initiate later. If the engine speed meets the minimum threshold condition, process 200 proceeds to operation 204.

[0032] Operation 204 assesses whether the steady-state engine speed, fuel system pressure (e.g., fuel system rail pressure), and accelerator pedal position meet minimum and / or maximum value conditions. If the aforementioned conditions are not met, process 200 may repeat operation 204, or may terminate and start or initiate later. If the aforementioned conditions are met, process 200 proceeds to operation 206.

[0033] Operation 206 assesses whether the engine fuel level meets the minimum threshold condition. If the engine fuel level does not meet the minimum threshold condition, process 200 proceeds to operation 208. If the engine fuel level meets the minimum threshold condition, process 200 proceeds to operation 219.

[0034] Operation 208 assesses whether the no-load engine condition is met (e.g., whether the engine is motorized or passively driven by an external load). If the no-load engine condition is not met, process 200 proceeds to operation 209, which discards the current data and returns to operation 202, or terminates process 200 or terminates process 200 that can be started or initiated later. If the no-load engine condition is met, process 200 proceeds to operation 210.

[0035] Operation 210 receives input 220 indicating the current cylinder in the firing sequence and, in response to an engine speed signal output by an engine speed sensor operatively coupled to the engine, determines a cylinder-specific or per-cylinder engine speed characteristic. The engine speed characteristic includes the engine speed associated with the ignition event of the particular cylinder being evaluated. Operation 210 can be performed on each of a plurality of cylinders of the engine to determine the engine speed characteristic of each of the plurality of cylinders, and can be performed sequentially corresponding to the firing sequence of the plurality of cylinders, performed in parallel on the plurality of cylinders, or a combination of both, such as a series of parallel evaluations. From operation 210, process 200 proceeds to operation 212.

[0036] Operation 212 determines the cylinder-specific or per-cylinder deceleration (negative acceleration) of the currently ignited cylinder and evaluates the deceleration relative to an upper and lower limit. The deceleration is associated with the ignition event of the specific cylinder being evaluated. Operation 212 can be performed on each of a plurality of cylinders of the engine to determine the deceleration of each of the plurality of cylinders, and can be performed sequentially corresponding to the ignition sequence of the plurality of cylinders, performed in parallel on the plurality of cylinders, or a combination of both, such as a series of parallel evaluations. The evaluations performed by operation 212 can occur sequentially corresponding to the ignition sequence of the plurality of cylinders, occur in parallel on the plurality of cylinders, or a combination of both, such as a series of parallel evaluations.

[0037] The results of the assessment performed by operation 212 can be stored in the cylinder friction trend dataset 213 for use in pre-diagnostic or predictive maintenance assessments. If the cylinder deceleration of the cylinder being assessed exceeds the maximum limit, process 200 proceeds to operation 214, which marks the cylinder being assessed. Process 200 then proceeds to operation 216, which confirms possible valve jamming conditions, and operation 218, which sets a flag based on the possible valve jamming conditions.

[0038] If the cylinder deceleration of the cylinder being evaluated is less than the minimum limit, process 200 proceeds to the operation 215 of marking the cylinder being evaluated. Process 200 then proceeds to the operation 217 of confirming possible valve jamming conditions and the operation 218 of setting a flag based on the possible valve jamming conditions.

[0039] If the engine fuel value evaluated by operation 206 meets the minimum limiting condition, process 200 proceeds to operation 219, which evaluates whether the engine is operating under steady-state, transient, or high-load and high-speed conditions. If the rate of change of engine speed or engine acceleration is zero or below a predetermined limit, operation 219 determines that the engine is operating under steady-state conditions. The predetermined limit may be a steady-state engine speed (rpm) adjustment limit, such as + / - 5 rpm; it should be understood that this limit may be changed for other applications. When the engine speed changes or acceleration is not zero or exceeds the predetermined limit, operation 219 determines that the engine is operating under transient conditions. Operation 219 may determine that the engine is operating under high-load and high-speed conditions in response to the engine speed exceeding a high-speed threshold and the engine load exceeding a high-load threshold.

[0040] If operation 219 assesses that the engine is operating under steady-state conditions, process 200 proceeds to operation 222. Operation 222 receives input 220 indicating the currently ignited cylinder and, in response to an engine speed signal output by an engine speed sensor operatively coupled to the engine, determines a cylinder-specific or per-cylinder engine speed characteristic. The engine speed characteristic includes the engine speed associated with the ignition event of the particular cylinder being assessed. Operation 222 can be performed on each of a plurality of cylinders of the engine to determine the engine speed characteristic of each of the plurality of cylinders, and can be performed sequentially corresponding to the ignition sequence of the plurality of cylinders, performed in parallel on the plurality of cylinders, or a combination of both, such as a series of parallel assessments. The speed characteristics determined by operation 222 can be stored in a misfire trend dataset 223 for use in pre-diagnostic or predictive maintenance assessments. From operation 222, process 200 proceeds to operation 224.

[0041] Operation 224 determines the upper and lower limits (e.g., + / - predetermined values ​​or percentages) of the engine speed for the good (non-faulty) cylinder. From operation 224, process 200 proceeds to operation 226, where operation 226 evaluates the engine speed of the currently ignited cylinder relative to the upper and lower limits. Operation 226 can be performed on each of multiple cylinders of the engine, and can be performed sequentially corresponding to the firing order of the multiple cylinders, performed in parallel on multiple cylinders, or a combination of both, such as a series of parallel evaluations.

[0042] If operation 226 assesses that the engine speed of the currently ignited cylinder is outside the upper or lower limit, the operation marks the cylinder being assessed as potentially faulty, and process 200 proceeds to operation 240 to continue further assessment of the cylinder marked as potentially faulty.

[0043] If operation 219 assesses engine operation under transient conditions, process 200 proceeds to operation 232. Operation 232 receives input 220 indicating the currently ignited cylinder and, in response to an engine speed signal output by an engine speed sensor operatively coupled to the engine, determines cylinder-specific or per-cylinder engine speed characteristics. Engine speed characteristics include the engine speed associated with the ignition event of the specific cylinder being assessed. Operation 232 can be performed on each of a plurality of cylinders of the engine to determine the engine speed characteristics of each of the plurality of cylinders, and can be performed sequentially corresponding to the ignition sequence of the plurality of cylinders, performed in parallel on the plurality of cylinders, or a combination of both, such as a series of parallel assessments. The speed characteristics determined by operation 232 can be stored in a misfire trend dataset 223 for use in pre-diagnostic or predictive maintenance assessments. From operation 232, process 200 proceeds to operation 234.

[0044] Operation 234 determines the rate of change of acceleration or engine speed for a cylinder-specific or per-cylinder configuration. The rate of change of acceleration or engine speed is associated with the ignition event of the specific cylinder being evaluated. Operation 234 can be performed on each of a plurality of cylinders of the engine to determine the rate of change of acceleration or engine speed for each of the plurality of cylinders, and can be performed sequentially corresponding to the firing order of the plurality of cylinders, performed in parallel on the plurality of cylinders, or a combination of both, such as a series of parallel evaluations. From operation 234, process 200 proceeds to operation 236, which evaluates the rate of change of acceleration or engine speed of the currently ignited cylinder relative to an acceleration threshold. Operation 236 can be performed on each of a plurality of cylinders of the engine, and can be performed sequentially corresponding to the firing order of the plurality of cylinders, performed in parallel on the plurality of cylinders, or a combination of both, such as a series of parallel evaluations.

[0045] If operation 236 assesses that the rate of change of acceleration or engine speed of the cylinder being inspected is below an acceleration threshold, the operation marks the cylinder being evaluated as potentially faulty and process 200 proceeds to operation 240 to continue further evaluation of the cylinder marked as potentially faulty.

[0046] If operation 219 assesses engine operation under high load and high speed conditions, process 200 proceeds to operation 252, which performs exhaust manifold pressure-based diagnostics to assess potential engine misfire effects. Those skilled in the art, benefiting from this disclosure, will understand that such diagnostics can be implemented in various forms, evaluating exhaust manifold pressure information (e.g., information from exhaust manifold pressure sensors) relative to expected exhaust manifold pressure or pressure distribution during non-misfire operation. The output of operation 252 can be stored in a misfire trend dataset 223 for use in pre-diagnostic or predictive maintenance assessments.

[0047] It should be understood that process 200 may proceed to operation 252 in conjunction with operation 222 or 232, for example, in an embodiment that uses an engine speed sensor in conjunction with an exhaust manifold pressure (EMP) sensor to supplement EMP-based misfire diagnosis. It should be further understood that in some embodiments, operation 252 may be omitted.

[0048] From operation 240, process 200 proceeds to operation 242, which assesses whether a fuel system pressure drop (e.g., a decrease in fuel rail pressure) is observed. Operation 242 can be performed on each of the multiple cylinders of the engine, and can be performed sequentially corresponding to the firing order of the multiple cylinders, performed in parallel on the multiple cylinders, or a combination of both, such as a series of parallel assessments. The fuel system pressure drop can be measured during the injection window of the injector associated with the cylinder being assessed. The absence of an expected fuel system pressure drop can be considered an indication of injector failure. Therefore, if operation 242 assesses that the expected rail pressure drop is not observed (e.g., no rail pressure drop is observed, or a pressure drop less than the expected pressure drop threshold is observed), process 200 proceeds to operation 247, which identifies the injector being assessed as potentially faulty, and then proceeds to operation 249, which marks the injector being assessed for inspection, testing, or repair.

[0049] It should be understood that in some implementations, the assessment of fuel system pressure drop may be omitted, for example in implementations that do not have an injector associated with each cylinder, such as port injection engines or engines that introduce fuel at various locations upstream of the cylinders, such as in some gas-fueled engines or multi-fuel engines that include gas fuel.

[0050] If operation 242 assesses and observes the expected rail pressure drop (e.g., observes a pressure drop, or observes a pressure drop above the expected pressure drop threshold), process 200 proceeds to operation 244 to assess whether it indicates a misfire condition in multiple cylinders. If operation 244 assesses and detects a misfire condition in multiple cylinders, process 200 proceeds to operation 245, which identifies a potential airflow fault and may also set one or more flags for inspection, testing, or repair of one or more air handling components (e.g., throttle body, EGR valve, EGR cooler, boost air cooler, or turbocharger, etc.).

[0051] If operation 244 assesses that no misfire condition is detected in multiple cylinders, process 200 proceeds to operation 246, which identifies a cylinder fault (e.g., a bad cylinder ring or piston ring). From operation 246, process 200 proceeds to operation 248, which also receives the value of a flag set by operation 218. If both the output of operation 246 and the flag value set by operation 218 are true, operation 248 identifies a cylinder fault and may also set one or more flags for inspection, testing, or repair of the cylinder or its related components.

[0052] Process 200 may perform a number of control operations in response to a misfire determination (e.g., in response to any of operations 245, 246, 248, and 252). For example, in response to a misfire determination, process 200 may modify engine operation, for example, by disabling one or more cylinders, limiting engine speed and / or engine torque, restricting engine operation to a limited range of the engine operating diagram, entering limp mode, modifying fuel injection parameters, or other operational modifications as may be conceived by those skilled in the art benefiting from this disclosure. Alternatively or additionally, in response to a misfire determination, process 200 may provide operator-perceptible outputs instructing maintenance actions, such as illuminating a malfunction indicator lamp (MIL), setting a readable fault code, or transmitting a fault indication.

[0053] Process 200 provides an example of control integrated with a system that can be implemented in the system and is operable in the process, said system including a reciprocating piston engine configured to output torque to drive a load, an engine speed sensor operatively coupled to said engine and configured to output an engine speed signal, and an electronic control system operatively coupled to a powertrain. Process 200 further provides an example of control in which the electronic control system is configured and / or operable to operate the engine to drive the load according to load demand, and during engine operation, to demand drive the load according to the load and to determine engine acceleration in response to the engine speed signal and to detect engine misfire in response to said engine acceleration.

[0054] It should be understood that load requirements can include load requirements in many tasks, including, for example, requirements corresponding to operator requirements such as accelerator pedal position, requirements corresponding to cruise control system commands or requests, requirements corresponding to autonomous driving assistance system commands or requests, requirements corresponding to autonomous or semi-autonomous vehicle control system commands or requests, requirements corresponding to load controller commands or requests (e.g., electric load controller commands or requests, pump load controller commands or requests, or compressor load controller commands or requests), and requirements corresponding to combinations of the foregoing examples with each other and / or with load requirements in other tasks.

[0055] It should also be understood that providing or operating an electronic control system can provide many desirable characteristics, said electronic control system being configured and / or operable to operate the engine to drive the load according to load demand, and during engine operation, driving the load according to load demand and determining engine acceleration in response to engine speed signals and detecting engine misfire in response to engine acceleration. For example, such systems and methods can avoid the need to modify the operation in response to load demand to perform tests or diagnostics to detect misfire, for example, by requiring the engine to operate at a specified speed, load or other operating conditions. In addition, such systems and methods can allow misfire to be determined over a wide range of the engine operating diagram, for example, including the range of low-speed, low-load operation (e.g., operation at or near (e.g., + / -5%) idle speed and idle load), the range of operation at or near (e.g., + / -5%) rated speed and rated load, the range of operation at or near (e.g., + / -5%) maximum speed and maximum load, the range including two or more of the previous ranges, the range including all the previous ranges, the range including one or more of the previous ranges combined with other ranges, and the range including two or more of the previous ranges combined with other ranges.

[0056] As should be further understood from the preceding description, process 200 provides an example of control that is implementable and operable to detect misfire during transient operation of the engine. Process 200 also provides an example of control that is implementable and operable to identify the cause of misfire (e.g., distinguishing between (a) injector malfunction, (b) airflow malfunction, and (c) compression malfunction as causes of misfire). Process 200 provides an example of control that is implementable and operable to detect misfire in response to the output of an engine speed sensor at either a peak or a trough of the engine speed signal provided by the engine speed sensor. Process 200 provides an example of control that is implementable and operable to detect misfire in response to a single engine speed measurement for each cylinder cycle. A single engine speed signal may correspond to a trough of the engine speed signal. Alternatively, a single engine speed signal may correspond to a peak of the engine speed signal.

[0057] refer to Figures 2D to 2E The figure illustrates certain aspects of an example engine misfire diagnostic process 200', which may be combined with one or more components of the electronic control system associated with the engine system (e.g., combined with...). Figure 1The system 10 described herein is implemented and performed in the controller 42, or one or more alternative or additional components of the electronic control system, as well as in other systems (e.g., separate diagnostic systems or repair tools for cylinders or injectors that can be operatively coupled to the engine system and its electronic control system and are used for diagnosing or detecting faults). It should be understood that the engine misfire diagnostic process 200' is an example illustrating the extension of the engine misfire diagnostic process 200 to additional systems such as the aforementioned diagnostic systems or repair tools, diesel engines with mechanical fuel systems, off-highway vehicles, populations, and other off-highway applications.

[0058] refer to Figure 2E The diagram illustrates certain aspects of control logic 100, which can be implemented and used in conjunction with, for example, an engine misfire diagnostic process 200' and electronic control system components associated with said process. Control logic 100 illustrates multiple options for confirming the currently ignited cylinder variable 130 in response to cylinder ignition variable 102, both variables of which can be stored in one or more non-transitory, controllable readable memory devices or media. Ignition cylinder variable 102 includes an indication of which engine cylinder is igniting. The currently ignited cylinder variable 130 includes an indication of which of a plurality of engine cylinders is igniting.

[0059] In the case of an engine including a common rail or other electronically or electrically controlled refueling system 112, crank and / or cam synchronization operation 114 can be performed to identify which of the multiple engine cylinders is igniting in response to a cam angle value or crank angle value. The current ignition cylinder variable 130 can be established or set in response to this synchronization.

[0060] In the case of an engine including a mechanical or mechanically controlled refueling system 112, additional setting operations can be performed to specify or provide a reference that allows identification of the top dead center (TDC) position of at least the first cylinder (e.g., any particular cylinder among a plurality of engine cylinders). The current ignition cylinder variable 130 can be established or set in response to such reference and identification.

[0061] Further reference Figure 2D The engine misfire diagnostic process 200' includes many features, which are combined with Figures 2A to 2C The illustrated and described engine misfire diagnosis process 200 has the same or substantially similar features. For the sake of brevity, many of these features are not repeated in the illustrations or descriptions of the engine misfire diagnosis process 200'. However, these features, including, for example, those combined with Figure 2A and Figure 2B The features illustrated and described herein should be understood to apply to the engine misfire diagnostic procedure 200' unless otherwise stated below.

[0062] refer to Figure 2D The diagram illustrates certain aspects of an engine misfire diagnostic process 200' that differs from engine misfire diagnostic process 200. For example, process 200' proceeds from operation 240 to operation 242', which assesses whether a positive fuel injection signal is observed. As mentioned above, in some systems, such as common rail fuel systems, a positive fuel injection signal may include a fuel rail pressure drop that can be measured during the injection window of a given cylinder. In other forms, a positive fuel injection signal may include electrical characteristics, such as injector ignition characteristics. In yet another form, a positive fuel injection signal may be, for example, a rail pressure rise that occurs in some engines including mechanically fueled systems (where improper injection causes a rise in fuel pressure).

[0063] Operation 242' can be performed on each of the multiple cylinders of the engine, and can be performed sequentially according to the firing order corresponding to the multiple cylinders, performed in parallel on the multiple cylinders, or a combination of both, such as a series of parallel evaluations. The positive fuel injection signal can be measured during the injection window of the injector associated with the cylinder being evaluated. The absence of the expected positive fuel injection signal can be considered an indication of injector malfunction. Therefore, if operation 242' evaluates and does not observe the expected positive fuel injection signal (e.g., no positive fuel injection signal is observed, or a positive fuel injection signal less than the expected value or threshold is observed), process 200' proceeds to operation 247, from which process 200' proceeds as described above. Therefore, if operation 242' evaluates and observes the expected positive fuel injection signal (e.g., a positive fuel injection signal is observed, or a positive fuel injection signal greater than the expected value or threshold is observed), process 200' proceeds to operation 244, from which process 200' proceeds as described above.

[0064] It should be understood that in some implementations, the evaluation of the positive fuel injection signal may be omitted, for example in implementations that do not have an injector associated with each cylinder, such as port injection engines or engines that introduce fuel at various positions upstream of the cylinders, such as in the case of certain gas fuel engines or multi-fuel engines that include gas fuel, or in implementations where injection is mechanically commanded without any electrical command or feedback.

[0065] refer to Figure 3 The figure illustrates an example engine misfire pre-diagnostic system 300, which can be implemented and executed in conjunction with a pre-diagnostic component 310. The pre-diagnostic component 310 may include one or more components of a computing system associated with the engine system, for example, in conjunction with... Figure 1The described system 10 includes a controller 42, an engine external electronic control system computing system, or one or more alternative or additional computing systems. A pre-diagnostic component 310 receives a cylinder friction trend dataset 213 and uses the dataset to build a friction model 313. The pre-diagnostic component 310 also receives a misfire trend dataset 223 and uses the dataset to build a misfire model 323. The pre-diagnostic component 310 also includes a trend analysis block 330 that uses the friction model 313 and the misfire model 323 to predict future engine failure events. It should be understood that the engine misfire pre-diagnostic system 300 is an example of a system operable to detect engine maintenance actions in response to multiple misfire detections.

[0066] refer to Figure 4A , Figure 4B and Figure 4C The figures 410, 420, and 430 illustrate certain aspects of the example misfire detection technique. Graph 410 shows engine speed (rpm) on its vertical axis and crankshaft angle (CAD) on its horizontal axis, and also indicates the ignition zone and firing order for each of the six cylinders; in the illustrated embodiment, the firing order is cylinder 5, cylinder 3, cylinder 6, cylinder 2, cylinder 4, and cylinder 1. Graph 410 also shows the crankshaft angle sensor signal 412 of the engine when each cylinder is correctly ignited and the crankshaft angle sensor signal 414 of the engine when a cylinder misfires. Crankshaft angle sensor signals 412 and 414 include multiple ignition peaks, which are the maximum engine speeds at which the ignition events of the respective cylinders occur; for example, the ignition peak 411 of signal 412 corresponds to the ignition peak of the fifth cylinder (cylinder 5) of the example engine. Crank angle sensor signals 412 and 414 include multiple compression valleys, which are the minimum engine speeds at which the compression events of individual cylinders occur. For example, compression valley 413 of signal 412 corresponds to the compression valley of the fifth cylinder (cylinder 5) of the example engine. As shown in graph 410, the engine speeds from the crankshaft speed sensor illustrate the oscillations when plotted in the crankshaft angle domain. By comparing signals 412 and 414, it can be seen that when misfire occurs, the ignition peak cannot recover speed, and the subsequent cylinder compression valleys show a significant decrease compared to the previous cycle. Therefore, by monitoring engine speed (i.e., acceleration) changes over a cycle, misfire can be detected and distinguished from normal cylinder ignition.

[0067] Graph 420 shows engine acceleration (rpm / s) on its vertical axis and crankshaft angles (CAD) on its horizontal axis. Graph 420 also shows the determined engine acceleration 422 for each cylinder when correctly ignited and the determined engine acceleration 424 for each cylinder when misfired. In the example of graph 420, engine acceleration is calculated at each available time step, including multiple samples of each cylinder's ignition and compression events. Graph 430 shows engine acceleration (rpm / s) on its vertical axis and crankshaft angles (CAD) on its horizontal axis. Graph 430 also shows the determined engine acceleration value 432 for each cylinder when correctly ignited and the determined engine acceleration value 434 for each cylinder when misfired. In the example of graph 420, engine acceleration is calculated at each available time step, including multiple samples of each cylinder's ignition and compression events. Comparing curves 420 and 430 reveals that determining acceleration within a single cylinder cycle enhances the separation between engine misfire events and normal engine ignition events, thereby improving the ability to detect misfire events. It can also be seen that determining engine acceleration at the compression trough further enhances the separation between engine misfire events and normal engine ignition events, thus improving the ability to detect misfire events.

[0068] refer to Figure 5 The figure 500 illustrates certain aspects of an example misfire detection technique. Graph 500 shows engine acceleration (rpm / s) on its vertical axis and the fuel quantity difference (mg / stroke) between the current ignition cylinder cycle and the previous ignition cylinder cycle on its horizontal axis. Graph 500 also shows multiple data points 512 for correct cylinder ignition under various engine fuel loads, multiple data points 514 for cylinder misfire, and data point 516 for post-misfire detonation. As can be seen from graph 500, the acceleration metric caused by load / speed changes is significantly lower than that caused by misfire. Therefore, comparing fuel load with the previous cycle (X-axis) can help filter out sudden fuel load drops. For example, the acceleration in six cylinders (720 CAD) can be compared to the acceleration in one cylinder (120 CAD) to distinguish between slow speed changes (indicating normal ignition) and rapid speed changes (indicating misfire). As can also be seen from graph 500, the acceleration metric for misfire is much larger in magnitude than the acceleration metric caused by load / speed changes. Therefore, it is possible to define regions using graph 500, which indicates normal cylinder ignition (e.g., region 512), cylinder misfire (e.g., region 514), and cylinder knock (e.g., region 516).

[0069] refer to Figure 6The figure illustrates a graph 600 illustrating certain aspects of an example misfire detection technique. Graph 600 shows engine output (torque) on its vertical axis and engine speed (rpm) on its horizontal axis. Graph 600 also shows an effective region 510 (including sub-region 512) in which engine misfire diagnosis according to this disclosure can be effectively performed. It should be understood that effective region 510 includes all regions under the engine torque curve except for the high-speed, low-load regions. It should also be understood that effective region 510 includes operation at idle and all loads, rated speed (except for low load in region 520), peak torque, and rated torque. During operational use, the range of effective region 510 is effective in both steady-state and transient operation. It should also be understood that sub-region 512 of effective region 510 is an example of a region where misfire diagnosis based on exhaust manifold pressure is ineffective due to weak exhaust pulsation, while engine misfire diagnosis according to this disclosure is effective in sub-region 512. The inventors have determined that screening known engine accelerations (e.g., using a three-point moving average, or other easing techniques) can further enhance misfire detection at higher engine speeds.

[0070] As should be understood from this disclosure, this disclosure covers multiple embodiments including the following examples. A first example embodiment is a system comprising: a reciprocating piston engine configured to output torque to drive a load; an engine speed sensor operatively coupled to the engine and configured to output an engine speed signal; and an electronic control system communicating with the engine and configured to receive the engine speed signal during engine operation, and during engine operation, determining engine acceleration in response to the engine speed signal and detecting engine misfire in response to the engine acceleration.

[0071] In some forms of the first example embodiments, the electronic control system is configured and operable to control the operation of the engine in response to demand load. In some forms of the first example embodiments, the electronic control system is configured to detect the misfire during transient operation of the engine based on load demand. In some forms of the first example embodiments, the electronic control system is configured to identify the cause of the misfire. In some forms of the first example embodiments, the electronic control system is configured to distinguish between (a) injector failure, (b) airflow failure, and (c) compression failure as the cause of the misfire. In some forms of the first example embodiments, the electronic control system is configured to detect the misfire in a series of engine operations, including engine operation at idle speed and idle torque, operation at rated speed and rated torque, and operation at maximum speed and maximum torque. In some forms of the first example embodiments, the electronic control system is configured to detect the misfire in response to the output of an engine speed sensor at one of the peak and trough values ​​of the engine speed signal provided by the engine speed sensor. In some forms of the first example embodiment, the electronic control system is configured to detect the misfire in response to a single engine speed measurement for each cylinder cycle. In some forms of the first example embodiment, the single engine speed measurement corresponds to a valley in the engine speed signal. In some forms of the first example embodiment, at least one of the following is present: (a) the electronic control system is configured to perform multiple misfire detections to predict engine maintenance actions; (b) the electronic control system is configured to perform operational diagnostics, the diagnostics being configured to monitor engine health over time and output pre-diagnostic recommendations; and (c) the electronic control system monitors engine health over time and provides pre-diagnostic recommendations based on trends in at least one of cylinder ignition and mechanical degradation. In some forms of the first example embodiment, the electronic control system is configured to perform at least one of the following: modifying engine operation in response to determining the engine misfire, and providing operator-perceptible output instructing maintenance actions. In some forms of the first example embodiment, the detection of the engine misfire in response to engine acceleration is performed in a component of the electronic control system inherent in the engine itself. In some forms of the first example embodiment, the engine includes a mechanical refueling system. In some forms of the first example implementation, the engine includes an electronic refueling system.In some forms of the first example implementation, the detection of engine misfire in response to engine acceleration is performed in an external diagnostic system component of the electronic control system, the external diagnostic system component being separate from and configured to be operatively coupled to the component of the electronic control system inherent in the engine itself.

[0072] A second example embodiment is a method comprising: an operating system including a reciprocating piston engine configured to output torque to drive a load, an engine speed sensor operatively coupled to the engine and configured to output an engine speed signal, and an electronic control system in communication with the engine speed sensor; operating the electronic control system to receive the engine speed signal during operation of the engine, and during operation of the engine, determining engine acceleration using the electronic control system in response to the engine speed signal, and detecting engine misfire using the electronic control system in response to the engine acceleration.

[0073] In some forms of the second example embodiment, the action of detecting the misfire of the engine using the electronic control system in response to engine acceleration includes detecting the misfire during transient operation of the engine according to load requirements. In some forms of the second example embodiment, the method includes using the electronic control system to identify the cause of the misfire. In some forms of the second example embodiment, the action of identifying the cause of the misfire using the electronic control system includes using the electronic control system to distinguish between (a) injector malfunction, (b) airflow malfunction, and (c) compression malfunction as the cause of the misfire. In some forms of the second example embodiment, the action of detecting the misfire of the engine using the electronic control system in response to engine acceleration includes detecting the misfire during a series of engine operations, including engine operation at idle speed and idle torque, operation at rated speed and rated torque, and operation at maximum speed and maximum torque. In some forms of the second example embodiment, the action of detecting the misfire of the engine using the electronic control system in response to engine acceleration includes detecting the misfire in response to the output of an engine speed sensor at either a peak or a trough of an engine speed signal provided by the engine speed sensor. In some forms of the second example embodiment, the method includes detecting the misfire in response to a single engine speed measurement for each cylinder cycle. In some forms of the second example embodiment, the single engine speed measurement corresponds to a trough of the engine speed signal. In some forms of the second example embodiment, the method includes at least one of: (a) predicting maintenance actions for the engine in response to multiple misfire detections; (b) operational diagnostics configured to monitor engine health over time and output pre-diagnostic recommendations; and (c) monitoring engine health over time and providing pre-diagnostic recommendations based on trends in at least one of cylinder ignition and mechanical degradation. In some forms of the second example embodiment, the method includes operating the electronic control system to perform at least one of: modifying the operation of the engine in response to determining the misfire of the engine, and providing operator-perceptible output instructing maintenance actions. In some forms of the second example embodiment, the method is performed by components of the electronic control system inherent in the engine itself. In some forms of the second example embodiment, the engine includes a mechanical refueling system. In some forms of the second example embodiment, the engine includes an electronic refueling system.In some forms of the second example implementation, the method is performed at least in part by an external diagnostic system component of the electronic control system, which is separate from and configured to be operatively coupled to the component of the electronic control system inherent in the engine itself.

[0074] A third example embodiment is a computer device for performing diagnostics on a reciprocating piston engine, the computer device comprising: an interface configured to communicatively connect to the engine and receive information indicating engine speed; and a processor configured to execute instructions stored in a non-transitory computer-readable storage medium to process the information indicating engine speed, determine engine acceleration in response to the information indicating engine speed, and detect engine misfire in response to the engine acceleration.

[0075] In some forms of the third exemplary embodiment, the processor is provided as a component of a standalone diagnostic device. In some forms of the third exemplary embodiment, the processor is configured to be operatively coupled to a mechanically controlled engine. In some forms of the third exemplary embodiment, the processor is provided as a component of an on-engine system. In some forms of the third exemplary embodiment, the processor is configured to detect the misfire during transient operation of the engine based on load requirements. In some forms of the third exemplary embodiment, the processor is configured to identify the cause of the misfire. In some forms of the third exemplary embodiment, the processor is configured to distinguish between (a) injector failure, (b) airflow failure, and (c) compression failure as the cause of the misfire. In some forms of the third exemplary embodiment, the processor is configured to detect the misfire during a series of engine operations, including engine operation at idle speed and idle torque, operation at rated speed and rated torque, and operation at maximum speed and maximum torque. In some forms of the third example embodiment, the processor is configured to detect the misfire in response to the output of the engine speed sensor being either a peak or a trough in the engine speed signal provided by the engine speed sensor. In some forms of the third example embodiment, the processor is configured to detect the misfire in response to a single engine speed measurement for each cylinder cycle. In some forms of the third example embodiment, the single engine speed measurement corresponds to a trough in the engine speed signal.

[0076] As should be understood from the preceding description, some example embodiments include one or more unique features that, while not necessary or required for all embodiments, provide unique aspects of certain embodiments. Some embodiments utilize engine speed sensors, such as engine crankshaft sensors, without requiring any additional sensors. Some embodiments utilize a combination of engine speed sensors and exhaust manifold pressure (EMP) sensors to supplement EMP-based misfire diagnostics. Some embodiments operate during engine operation in a mission without requiring specific test modes or operations. Some embodiments distinguish transient engine load noise from misfire events. Some embodiments provide diagnostics for effective operation across most of the speed-torque domain of the engine operating diagram. Some embodiments identify the cause of misfire and / or differentiate between multiple potential causes of misfire. Some embodiments provide pre-diagnostics for engine health monitoring and / or predictive maintenance. Some embodiments include aspects of the preceding example embodiments combined with each other and / or with other aspects and features previously described.

[0077] Although exemplary embodiments of the present disclosure have been shown and described in detail in the accompanying drawings and the preceding description, these exemplary embodiments are intended to be illustrative rather than restrictive in nature. It should be understood that only certain exemplary embodiments have been shown and described, and all variations and modifications falling within the spirit of the claimed invention are intended to be protected. It should be understood that although the use of terms such as preferred, especially, or more preferred in the foregoing description indicates that such described features may be more desirable, but may not be necessary, and embodiments lacking such features are contemplated within the scope of the invention, defined by the appended claims. When reading the claims, it is intended that when words such as “a,” “an,” “at least one,” or “at least a portion” are used, the claim is not intended to be limited to a single item unless the contrary is specifically stated. 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 the contrary is specifically stated.

Claims

1. A system for misfire detection using an engine speed sensor, the system comprising: A reciprocating piston engine configured to output torque to drive a load; The engine speed sensor is operatively connected to the engine and configured to output an engine speed signal; An electronic control system, which communicates with the engine and is configured to receive an engine speed signal during engine operation, determine engine acceleration based on the engine speed signal, determine whether the engine is operating under one of the following conditions: no-load condition, steady-state condition, transient condition, and high-load and high-speed condition; if the engine is operating under no-load condition, assess cylinder deceleration to determine one of possible valve sticking open and possible valve sticking closed conditions, and determine engine misfire based on: the engine speed signal if the engine is operating under steady-state condition; the engine acceleration if the engine is operating under transient condition; and a diagnostic based on exhaust manifold pressure if the engine is operating under high-load and high-speed condition. as well as Pre-diagnostic component, configured for: Receive cylinder friction trend dataset and use the cylinder friction trend dataset to establish a friction model; as well as The system receives a misfire trend dataset and uses it to build a misfire model, wherein the pre-diagnostic component includes a trend analysis block that uses a friction model and a misfire model to predict future failure events of the engine.

2. The system of claim 1, wherein the electronic control system is configured to detect the misfire during transient operation of the engine according to load requirements.

3. The system of claim 1, wherein the electronic control system is configured to identify the cause of the fire.

4. The system of claim 3, wherein the electronic control system is configured to distinguish between (a) injector malfunction, (b) airflow malfunction, and (c) compression malfunction as the cause of the misfire.

5. The system of claim 1, wherein the electronic control system is configured to detect the misfire during a series of engine operations, the series of engine operations including engine operation at idle speed and idle torque, operation at rated speed and rated torque, and operation at maximum speed and maximum torque.

6. The system of claim 1, wherein the electronic control system is configured to detect the misfire in response to the output of the engine speed sensor at one of the peak and valley values ​​of the engine speed signal provided by the engine speed sensor.

7. The system of claim 1, wherein the electronic control system is configured to detect the misfire in response to a single engine speed measurement for each cylinder cycle.

8. The system of claim 7, wherein the single engine speed measurement result corresponds to the valley value of the engine speed signal.

9. The system of claim 1, wherein at least one of the following is present: (a) the electronic control system is configured to predict maintenance actions for the engine in response to multiple misfire detections; (b) the electronic control system is configured to perform operational diagnostics, the diagnostics being configured to monitor engine health over time and output pre-diagnostic recommendations; and (c) the electronic control system monitors engine health over time and provides pre-diagnostic recommendations based on trends in at least one of cylinder ignition and mechanical degradation.

10. The system of any one of claims 1 to 9, wherein the electronic control system is configured to perform at least one of the following operations: modifying the operation of the engine in response to determining the misfire of the engine, and providing an operator-perceptible output instructing maintenance actions.

11. A method for misfire detection using an engine speed sensor, the method comprising: An operating system, the system comprising: a reciprocating piston engine configured to output torque to drive a load; an engine speed sensor operatively connected to the engine and configured to output an engine speed signal; and an electronic control system communicating with the engine speed sensor; During engine operation, the electronic control system is operated to perform the following actions: receiving the engine speed signal, determining whether the engine is operating under one of the following conditions: no-load condition, steady-state condition, transient condition, and high-load and high-speed condition, and one of the following: (a) if the engine is operating under the steady-state condition, detecting engine misfire in response to the engine speed signal; (b) if the engine is operating under the transient condition, determining engine acceleration in response to the engine speed signal and detecting engine misfire in response to the engine acceleration; (c) if the engine is operating under the high-load and high-speed condition, detecting engine misfire in response to a diagnostic based on exhaust manifold pressure; and (d) if the engine is operating under no-load condition, evaluating cylinder deceleration to determine one of possible valve stick-open and possible valve stick-close conditions; and The pre-diagnostic component is operated to receive a cylinder friction trend dataset and construct a friction model using the cylinder friction trend dataset; and to receive a misfire trend dataset and construct a misfire model using the misfire trend dataset, and the operation of the pre-diagnostic component includes operating a trend analysis block included in the pre-diagnostic component to predict future failure events of the engine using the friction model and the misfire model.

12. The method of claim 11, wherein the action of detecting the misfire of the engine in response to the engine acceleration includes detecting the misfire during transient operation of the engine according to load requirements.

13. The method of claim 11, wherein the method includes using the electronic control system to identify the cause of the fire.

14. The method of claim 13, wherein the action of using the electronic control system to identify the cause of the fire includes using the electronic control system to distinguish between (a) injector malfunction, (b) airflow malfunction, and (c) compression malfunction as the cause of the fire.

15. The method of claim 11, wherein the action of detecting the misfire of the engine in response to the engine acceleration includes detecting the misfire in a series of engine operations, the series of engine operations including engine operation at idle speed and idle torque, operation at rated speed and rated torque, and operation at maximum speed and maximum torque.

16. The method of claim 11, wherein the action of detecting the misfire of the engine in response to the engine acceleration includes detecting the misfire in response to the output of an engine speed sensor at one of the peak and trough values ​​of an engine speed signal provided by the engine speed sensor.

17. The method of claim 11, wherein the method includes detecting the misfire in response to a single engine speed measurement for each cylinder cycle.

18. The method of claim 17, wherein the single engine speed measurement result corresponds to the valley value of the engine speed signal.

19. The method of claim 11, the method comprising at least one of: (a) predicting maintenance actions for the engine in response to multiple misfire detections; (b) operational diagnostics configured to monitor engine health over time and output pre-diagnostic recommendations; and (c) monitoring engine health over time and providing pre-diagnostic recommendations based on trends in at least one of cylinder ignition and mechanical degradation.

20. The method of any one of claims 11 to 19, the method comprising operating the electronic control system to perform at least one of the following operations: modifying the operation of the engine in response to determining the misfire of the engine, and providing an operator-perceptible output instructing maintenance actions.

21. A computer device for performing diagnostics on a reciprocating piston engine, the computer device comprising: An interface configured to communicate with the engine and receive information indicating engine speed, and A processor, configured to execute instructions stored in a non-transitory computer-readable storage medium to: The engine acceleration is determined in response to the information indicating the engine speed. Determine whether the engine is operating under one of the following conditions: no-load condition, steady-state condition, transient condition, and high-load and high-speed condition. If the engine is operating under no-load conditions, the cylinder deceleration is evaluated to identify possible valve sticking open or valve sticking closed conditions, and The engine misfire is detected in the following ways: if the engine is operating under steady-state conditions, based on the engine speed signal; if the engine is operating under transient conditions, based on the engine acceleration; and if the engine is operating under high load and high speed conditions, based on a diagnosis based on exhaust manifold pressure. as well as Pre-diagnostic component, configured for: Receive cylinder friction trend dataset and use the cylinder friction trend dataset to establish a friction model; as well as The system receives a misfire trend dataset and uses it to build a misfire model, wherein the pre-diagnostic component includes a trend analysis block that uses a friction model and a misfire model to predict future failure events of the engine.

22. The computer device of claim 21, wherein the processor is configured to detect the misfire during transient operation of the engine according to load requirements.

23. The computer device of claim 21, wherein the processor is configured to identify the cause of the fire.

24. The computer device of claim 23, wherein the processor is configured to distinguish between (a) injector failure, (b) airflow failure, and (c) compression failure as the cause of the misfire.

25. The computer device of claim 21, wherein the processor is configured to detect the misfire during a series of engine operations, the series of engine operations including engine operation at idle speed and idle torque, operation at rated speed and rated torque, and operation at maximum speed and maximum torque.

26. The computer device of claim 21, wherein the processor is configured to detect the misfire in response to the output of an engine speed sensor in one of a peak and a trough of an engine speed signal provided by the engine speed sensor.

27. The computer device of claim 21, wherein the processor is configured to detect the misfire in response to a single engine speed measurement for each cylinder cycle.

28. The computer device of claim 27, wherein the single engine speed measurement result corresponds to a valley value of the engine speed signal.

29. A computer-readable medium comprising instructions that, when executed by a processor, cause the processor to perform the method of any one of claims 11-20.

30. A computer program product comprising instructions that, when executed by a processor, cause the processor to perform the method of any one of claims 11-20.

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