Abstract: Methods and systems for detecting misfire events in a multicylinder engine are disclosed. One method includes associating a neural network with a cylinder of a multicylinder engine. The method also includes inputting to the neural network a plurality of crankshaft parameters. The method further includes determining the existence of an engine misfire in the cylinder based on the output of the neural network.

Abstract: A system and method for detecting anomalies in a system are described. The system incorporates a diagnostic agent. The diagnostic agent identifies a current operational region of the system and determines current performance based on a local model of normal system performance in that region.

Abstract: A system and method for detecting anomalies and identifying root causes of anomalies in a system are disclosed. The system includes anomaly detection agents trained to detect anomalies. The anomalies are known anomalies occurring in the system. The anomaly detection agents are interfaced with components of a tested system, and operate on one or more predetermined levels, such as hierarchical or threshold levels. The system also includes a root cause identification tool configured to identify potential root causes for anomalies occurring during actual operation of the tested system based on data from the anomaly detection agents.

Abstract: A diagnostic/prognostic system monitors performance of a vehicle or other apparatus wherein the vehicle has a plurality of operational components. Each operational component has a predetermined nominal operating state and generates respective electrical signals pursuant to its operation. A data collection memory in the vehicle stores samples of the electrical signals in a rolling buffer. An analyzer in the vehicle is responsive to the electrical signals for detecting a trigger event indicative of at least a potential variance of an operational component from its nominal operating state. A computation center located remotely from the vehicle has a database storing representations of electrical signals for classifying nominal and irregular operating states of the operational components. A transmitter is activated by the trigger event to transmit at least some of the stored samples in the rolling buffer at the time of the trigger event to the computation center.

Abstract: A diagnostic/prognostic system monitors performance of a vehicle or other apparatus wherein the vehicle has a plurality of operational components. Each operational component has a predetermined nominal operating state and generates respective electrical signals pursuant to its operation. A data collection memory in the vehicle stores samples of the electrical signals in a rolling buffer. An analyzer in the vehicle is responsive to the electrical signals for detecting a trigger event indicative of at least a potential variance of an operational component from its nominal operating state. A computation center located remotely from the vehicle has a database storing representations of electrical signals for classifying nominal and irregular operating states of the operational components. A transmitter is activated by the trigger event to transmit at least some of the stored samples in the rolling buffer at the time of the trigger event to the computation center.

Abstract: An engine diagnostic system includes a bit-serial based recurrent neuroprocessor for processing data from an internal combustion engine in order to diagnose misfires in real-time and reduces the number of neurons required to perform the task by time multiplexing groups of neurons from a candidate pool of neurons to achieve the successive hidden layers of the recurrent network topology.

Abstract: A misfire detection assembly, used in conjunction with a motor vehicle having a fuel injector, an internal combustion engine and at least one output sensor, includes: a correlator which is electrically connected to the fuel injector and the output sensor wherein the correlator correlates firing events created by the fuel injector with an output signal created by the output sensor; a filter electrically connected to the correlator to receive the output signal and to compare the output signal against a variable threshold signal created by the filter; and a recorder, electrically connected to the filter, to record the firing events which exceed the variable threshold signal and those which do not exceed the variable threshold signal.

Abstract: Misfiring of individual cylinders in an internal combustion engine 70 is detected based on simultaneous use of two or more different methods of misfire detection which examine different combustion-related parameters of engine operation, such as crankshaft acceleration and exhaust gas pressure. An analyzer 76 produces a final misfire determination M.sub.f (i) based on the simultaneously obtained misfire determinations in order to provide greater coverage of the speed-load range of engine 70 and to provide increased confidence and accuracy in calling misfires in the portion of the speed-load range where both misfire methods are presumed to function.

Abstract: A crankshaft based misfire detector for an internal combustion engine detects and identifies misfire over a broad range of engine operating conditions by establishing correction factors to compensate for crankshaft torsional oscillations and static wheel profile errors which corrupt the acceleration signals used to detect misfire. The correction factors are adaptively determined during in-use engine operation and are updated in one manner for most firings but in another manner for any cylinder firing which had the relatively lowest corrected acceleration within an engine cycle.

Abstract: A system and method compensates for systematic irregularities in measured engine velocities caused by torsional flexing in the crankshaft during rotation to improve the accuracy of misfire detection. A set of generated correction factors is stored in a table that are derived empirically using a test engine. The correction factors are adjusted during on-board operation of the engine whenever a safe adaptation time is determined.

Abstract: A system and method for processing test measurements collected from an internal combustion engine that is cold-tested for diagnostic purposes. Test measurements are collected from an engine. The test measurements are "pre-processed" by filtering and subsampling techniques so that Principle Component Analysis can be applied to condense the quantity of test measurements while still retaining a statistically accurate indication of a majority of the original measurements. The pre-processed test measurements are then passed through one or more classifiers including: a Neural Network classifier, a Fuzzy Logic classifier, a cluster-based classifier (or "Spherical" classifier) and a Genetic Program classifier. Results from these classifiers can be used to obtain a verdict about an engine (i.e., whether the engine is "normal" or "faulty").

Abstract: Misfiring of individual cylinders in an internal combustion engine is detected based on sensing exhaust pressure during each operating cycle of the engine. A pressure signal is sampled and digitized during each cycle to form an input vector for a pattern classifier. Predetermined internal coefficients of the trained classifier enable the classifier to discriminate between firing and misfiring cylinders in real time with a high degree of accuracy. Overall system cost is reduced by sharing a pressure transducer with an exhaust gas recirculation system on the internal combustion engine.

Abstract: A method and apparatus are provided for reliably detecting misfires in an internal combustion engine during actual driving conditions by monitoring fluctuations in engine speed between consecutive firing intervals. An average acceleration over a series of firing intervals is removed from an individual acceleration measurement corresponding to a particular firing interval to give an acceleration deviation which is then normalized to an expected torque to provide a power loss measurement. The power loss measurement indicates the occurrence of a misfire with a high signal-to-noise ratio. The information derived from misfire detection can be used to prevent destruction of a catalytic converter by unburned fuel mixtures and can be used to improve vehicle driveability by correcting for or indicating needed service for the vehicle. The misfire detection is implemented using existing sensors and processors and is adapted to be done on-board a vehicle in real time.

Abstract: A method and apparatus are provided for reliably detecting misfires in an internal combustion engine during actual driving conditions by monitoring fluctuations in engine speed between consecutive firing intervals. An average acceleration over a series of firing intervals is removed from an individual acceleration measurement corresponding to a particular firing interval to give an acceleration deviation which is then normalized to an expected torque to provide a power loss measurement. The power loss measurement indicates the occurrence of a misfire with a high signal-to-noise ratio. The information derived from misfire detection can be used to prevent destruction of a catalytic converter by unburned fuel mixtures and can be used to improve vehicle driveability by correcting for or indicating needed service for the vehicle. The misfire detection is implemented using existing sensors and processors and is adapted to be done on-board a vehicle in real time.

Abstract: A method and apparatus are provided for reliably detecting misfires in an internal combustion engine during actual driving conditions by monitoring fluctuations in engine speed between consecutive firing intervals. An average acceleration over a series of firing intervals is removed from an individual acceleration measurement corresponding to a particular firing interval to five an acceleration deviation which is then normalized to an expected torque to provide a power loss measurement. The power loss measurement indicates the occurrence of a misfire with a high signal-to-noise ratio. The information derived from misfire detection can be used to prevent destruction of a catalytic converter by unburned fuel mixtures and can be used to improve vehicle driveability by correcting for or indicating needed sevice for the vehicle. The misfire detection is implemented using existing sensors and processors and is adapted to be done on-board a vehicle in real time.

Abstract: A method and apparatus are provided for reliably detecting misfires in an internal combustion engine during actual driving conditions by monitoring fluctuations in engine speed between consecutive firing intervals. An average acceleration over a series of firing intervals is removed from an individual acceleration measurement corresponding to a particular firing interval to give an acceleration deviation which is then normalized to an expected torque to provide a power loss measurement. The power loss measurement indicates the occurrence of a misfire with a high signal-to-noise ratio. The information derived from misfire detection can be used to prevent destruction of a catalytic converter by unburned fuel mixtures and can be used to improve vehicle driveability by correcting for or indicating needed service for the vehicle. The misfire detection is implemented using existing sensors and processors and is adapted to be done on-board a vehicle in real time.

Abstract: A system is disclosed for diagnosing faults in electronic control systems wherein a large volume of information is exchanged between the electronic control processor and a mechanical system under its control. The data is acquired such that parameter vectors describing the system operation are formed. The vectors are provided to a pattern recognition system such as a neural network for classification according to the operating condition of the electronically controlled system. For diagnosis of electronically controlled engine operation, the parameters included in the vectors correspond to individual firing events occurring in the engine operating under a predetermined condition. The diagnostic system can be implemented as a service tool in an automotive service bay or can be implemented within the on-board electronic control system itself.