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: 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: The invention estimates baseline acceleration expected from normal (i.e., non-misfiring) cylinders in an internal combustion engine even when the misfire rate reaches 50%. An offset median value is used to derive an average or gross acceleration value to provide a baseline rather than a true median. The offset median is the next largest value greater than the true median, so that the presence of 50% misfires does not degrade the determination of the baseline.

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: An apparatus for identifying the power stroke of a particular cylinder in a multi-cylinder engine which utilizes a wasted spark electronic distributorless ignition system but lacks a camshaft driven cylinder identification sensor, wherein a single sensor can be placed in a coil pack adjacent to and substantially equidistant from the ignition coil towers. The sensor will produce a signal reflecting the difference in voltage drops between corresponding pairs of spark plugs who share the same coil and which utilizes this signal to determine the power stroke of individual cylinders to produce a resulting synthetic cylinder identification signal. This apparatus can further be used as a permanent on-board sensor, thereby negating the need for a separate camshaft driven sensor, to determine the cylinder identification.

Abstract: A control system and control method are described for an engine (12) having a valve controller (42) for controlling exhaust valves (EV.sub.1-4) and intake valves (IV.sub.1-4) of each of the cylinders. Misfire detectors (210-302) provide an indication of ignition misfire in each of the cylinders each engine cycle. In response to a misfire detection, the valve lift of the exhaust valve for that cylinder is set to zero. If the misfire was absent during the cylinder's previous ignition cycle, the intake valve lift is also set to zero. After two successive misfire detections, the intake valve lift is set to a predetermined lift in order to refreshen the air/fuel charge which has been trapped in the cylinder from the previous engine cycles (402-428).

Abstract: The time needed to verify proper operation of a fault detection system or to verify the impact of the replacement of a component in the system being monitored is reduced without substantial increase in the possibility of false indication of failure or false indication of proper operation by employing a geometric moving average with a variable time constant reset to a minimum value upon initialization and gradually increasing to a maximum value. Motor vehicle systems and components are monitored and a diagnostic indicator annunciates faults to alert the vehicle operator to malfunctions.

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. The present invention compensates for irregularities in "Profile-Ignition-Pick-Up interval" (PIP interval) timing. These irregularities are systematic with respect to different engine cylinders. The present invention is configured to function with a processor unit. Correction factors for each of the n PIP intervals of an engine cycle are generated for each of a multitude of engine operating conditions, where n is the number of cylinders in the engine. Each set of n generated correction factor is stored in a table (a "look-up table" located in a memory unit) having a corresponding unique address location. This table is typically determined empirically in the calibration of the engine type by a test engine.

Abstract: System and method for filtering a misfire data stream having numerical values that indicate whether a firing of a cylinder was a misfire or a proper firing, to yield an optimum measurement misfire-rate for accurate and rapid determination of whether an engine is misfiring beyond a threshold level.

Abstract: Systematic errors in manufacturing of position markers of an internal combustion engine position sensing system are corrected by a procedure which detects nonuniformities in the placement of the position markers using an engine coastdown without combustion in the cylinders. Since the coastdown comprises a smooth deceleration, any nonuniformities detected in the velocities calculated for individual firing intervals during the coastdown are a manifestation of nonuniformities in the position marker placement. These nonuniformities are used to calculate correction factors which are stored for use when calculating velocities during engine combustion.

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: Engine crankshaft velocity is determined during each firing interval of an engine. Pairs of velocities are combined to yield acceleration measurements indicating the work done by a particular cylinder in its power stroke. A deviation of a particular acceleration value from that of neighboring values denotes a lack of power in the corresponding cylinder. The width and the phase of each velocity interval are used which provide accurate and substantially independent acceleration measures for each power stroke. Specifically, the width of each interval is preferably between about 45.degree.-180.degree. of engine rotation. Each interval has a phase in relation to its respective power stroke such that the drop in acceleration occurring in a particular power stroke causes a maximum drop in the calculated acceleration corresponding to that particular power stroke and causes a smaller but substantially equal drop in the calculated accelerations corresponding to the preceding and following power strokes.

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 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.

Abstract: A technique for measuring the ion implant dosage involves method and apparatus for directing pulses of coherent radiation from a laser to the surface of a semiconductor that has been subjected to ion implant. The intensity of the third harmonic reflected from the semiconductor is determined and correlated to determine the ion dosage within the semiconductor.