Abstract: An ignition system for an engine of a vehicle, comprising: a spark plug which includes: a central electrode electrically connected to an ignition coil, and a ground electrode, where the spark plug ignites a mixture of fuel and air in a normal mode of the engine; a high speed pulser to ignite the mixture of fuel and air in a lean-burn mode of the engine; a pulser controller to control the high speed pulser to ignite the mixture of fuel and air in the lean-burn mode of the engine; an engine control unit (ECU) that determines the normal and lean-burn modes based on an engine speed and an engine load, and controls the pulser controller and an ignition of the spark plug based on a determined mode among the normal mode and the lean-burn mode.

Abstract: Methods and systems are disclosed for operating an engine that includes a knock control system that may determine contributions of individual transient and steady-state noise sources to an engine background noise level. The contributions of the transient and steady-state individual noise sources may be the basis for establishing the presence or absence of knock in one or more engine cylinders.

Abstract: The ignition system (10) of an engine (particularly for a UAV) has a primary (10a), and a secondary (10b) ignition system to provide redundancy for ‘get you home’ capability should the primary ignition system fail. The secondary ignition provides a lower energy or shorter duration spark than the higher energy or longer duration sparking of the primary ignition system, and is retarded relative to primary sparking. Timing of the secondary sparking can be advanced in the event of primary sparking failure. Fuelling strategy can be shifted from a leaner stratified charge to a richer homogenous charge when relying just on the secondary ignition system for ignition. The secondary ignition system can be of a lower spark energy and/or duration than the primary ignition system, avoiding the cost, complexity and weight of replicating the primary ignition system, and to improve packaging within the engine housing, particularly within the limited payload and space limits of a UAV.

Abstract: A method for extracting characterizing features from an ion current trace retrieved from spark plugs of cylinders of an internal combustion engine, comprises the steps of: i. dividing the ion current signal into crank angle subintervals; ii. calculating a measure of ion current in each crank angle subinterval; and iii. Performing a calculation on the measure of ion currents from different subintervals such that the result of the calculation is dimension free. Further it relates to a method of monitoring combustion processes where a plurality of ion current signals from a number of spark plugs (4A, 4B) are retrieved and used in combination.

Abstract: The disclosure describes systems and methods of detecting a misfire in a cylinder of an engine. Such systems and methods may include determining a standard deviation for a crank angle location in a chamber of the engine, determining a standard deviation of the peak pressure in a chamber of the engine. If the standard deviation for a crank angle location is greater than a threshold value for the standard deviation for a crank angle, or if the standard deviation for the peak pressure is greater than a threshold value for the standard deviation of the peak pressure, an engine cylinder cut out check may be performed to identify one or more misfiring cylinders.

Abstract: An ignition coil apparatus for high-frequency discharge includes: a primary coil that generates and accumulates a flux; a secondary coil that is magnetically coupled to the primary coil so as to generate a predetermined high voltage when energy of the accumulated flux is released and connected at one end to a high-voltage terminal used to supply energy to an external apparatus; a capacitor that is connected to the high-voltage terminal and prevents passing of the high voltage; and an inductor that, together with the capacitor, allows passing of a predetermined frequency component alone. The primary coil, the secondary coil, the capacitor, and the inductor are installed within a same package.

Abstract: An ignition timing control device (31) has a knocking detection device (41) that detects knocking of internal combustion engine (1) and an ignition timing adjustment device (43) that receives a knocking signal outputted from the knocking detection device (41) and a signal concerning the ignition timing of internal combustion engine (1) outputted from an external electronic control unit (37) and adjusts the ignition timing of internal combustion engine (1) according to the knocking signal and the signal concerning the ignition timing. Further, the knocking detection device (41) and the ignition timing adjustment device (43) are electrically connected and formed integrally with each other.

Abstract: An engine method, comprising turning off a second cylinder group in response to engine load falling below a first threshold, the second cylinder group including a first outer most cylinder and its immediately adjacent cylinder and turning on the second cylinder group in response to engine load raising above a second threshold and operating a first cylinder group constantly throughout engine operation; the first cylinder group including a second outer most cylinder and its immediately adjacent cylinder. By this method, engine efficiency may increase during partial load operating conditions from low engine loads.

Abstract: Methods and systems are provided for addressing pre-ignition that may be induced in response to actions taken to mitigate a cylinder misfire. An amount of engine load limiting applied may be adjusted to reduce the likelihood pre-ignition while also addressing component over-temperature issues. By limiting an engine load while shutting off fuel in a misfiring cylinder, and while combusting a lean air-fuel mixture in the remaining cylinders, pre-ignition induced by the misfire-mitigating lean combustion conditions can be reduced.

Abstract: There is provided a combustion state detecting apparatus capable of detecting combustion-state abnormality in an internal combustion engine. A comparison timing is set to be advanced in terms of the rotation angle of the crankshaft of an internal combustion engine with respect to the ending timing of an electric quantity based on an ion that occurs when ignition is performed normally through a predetermined ignition signal among the plurality of ignition signals; in the case where, as a result of the comparison between the detected ending timing of an electric quantity based on an ion and the comparison timing, the ending timing is advanced in terms of the rotation angle of the crankshaft with respect to the comparison timing, it is determined that the combustion based on ignition through the predetermined ignition signal is abnormal.

Abstract: A system for a vehicle includes a misfire indication module, a valve control module, and a fault indication module. The misfire indication module selectively indicates that misfire occurred within a cylinder of an engine. The valve control module controls lifting of a valve of a cylinder of the engine and, in response to the misfire indication module indicating that misfire occurred within the cylinder, transitions lifting of the valve from one of a low lift state and a high lift state to the other one of the low lift state and the high lift state. The fault indication module selectively indicates that a fault is present in a variable valve lift (VVL) mechanism of the cylinder based on whether the misfire indication module indicates that misfire occurred within the cylinder after the transition to the other one of the low lift state and the high lift state.

Abstract: A self power circuit for ion sense circuitry is provided. The self power circuit is configured to supply the voltages required to generate and measure an ion current flow in a combustion chamber of an engine. The power circuit stores power from the current flow in the ignition coil secondary circuit during at least a portion of a sparking period for use during the ion current measurement period between sparking events. Ion current generation voltage as well as positive and negative sensor circuit power supply voltages are generated in one embodiment.

Abstract: An engine control system includes a disturbance module, a misfire threshold determination module, a disturbance ratio module, and a spark control module. The disturbance module determines a disturbance value for a past combustion stroke of a cylinder based on rotation of a crankshaft. The misfire threshold determination module determines a jerk value indicative of a misfire within the cylinder. The disturbance ratio module determines a disturbance ratio for the past combustion stroke based on the disturbance value and the jerk value. The spark control module determines a spark timing for a future combustion stroke of the cylinder, determines a spark timing correction for the future combustion stroke based on the disturbance ratio, determines a corrected spark timing based on the spark timing and the spark timing correction, and generates spark during the future combustion stroke based on the corrected spark timing.

Abstract: Embodiments for a turbocharged engine are provided. In one example, a method for operating a supercharged internal combustion engine including at least one exhaust-gas turbocharger which has a turbine arranged in an exhaust-gas discharge system and a compressor arranged in an intake system, comprises during a load increase ?pme, retarding ignition timing away from an ignition time ?Z,opt optimized with regard to efficiency and beyond an ignition time ?Z,knock, where ?Z,knock is an earliest ignition time to avoid knocking combustion.

Abstract: When the internal combustion engine is in an injection-free operating mode, a selected injector is open for injecting a small fuel amount, whereby at least one working cycle with injector control follows or precedes one cycle without control, a differential of two subsequent segment times of the cylinder associated with the selected injector or another variable, that reproduces a temporal crankshaft angle speed modification, is determined as a measurement value respectively for the cycle with and without control, and a relation is formed between the values of the cycles with or without control and used to correct the injection characteristic curve. The engine operates with active ignition and the value for the cycle with control is tested by taking into account ignition faults and the relation is only used to correct the curve if the value in the cycle with control significantly deviates from the one without control.

Abstract: A method is provided for controlling an internal combustion engine. The method includes, but is not limited to the step of measuring in-cylinder pressure of an expansion phase of a combustion cycle of a cylinder of the internal combustion engine and measuring in-cylinder pressure of a compression phase of the combustion cycle of the cylinder of the internal combustion engine. A difference between a polytrophic expansion phase constant of the cylinder of the internal combustion engine and a polytrophic compression phase constant of the cylinder of the internal combustion engine is then determined using the measured expansion phase pressure and the measured compression phase pressure. A misfiring of the cylinder is later detected using the determined difference.

Abstract: When an insulation resistance value of an ignition plug is smaller than a prescribed value, an engine operation state is switched so as to raise a temperature of the ignition plug, thereby promoting deposit cleaning. Such a measures-against-deposit carrying-out state is counted. When a count value exceeds a certain value, that is, when the measures against deposit have sufficiently been performed but the insulation resistance value of the ignition plug is smaller than the prescribed value, it is determined that conductive deposit has adhered to the ignition plug, and for example, an alarm light is turned on in order to urge a driver to perform maintenance of the ignition plug.

Abstract: The present invention is a method for reducing misfire in a cylinder of an internal combustion engine. The method includes detecting a misfire event frequency that is equal to or greater than a first predetermined value, determining a pulse-width signal for a fuel injector associated with the cylinder during the misfire event, increasing the pulse-width signal if the misfire event is frequency is below a second predetermined value, and reducing the increase in the pulse-width signal if the misfire event frequency is below the first predetermined value.

Abstract: An on-board diagnostic system of a vehicle comprises disabling diagnostic operation, such as a misfire monitor, based on road roughness. In one example, the disabling of the diagnostic operation is based on brake actuation and degradation of an anti-lock braking system.

Abstract: In a motor vehicle with idle stop function, upon satisfaction of preset engine restart conditions (step S205), automatic engine restart control refers to a preset map representing a variation in amount of fuel Q1, which is to be initially injected into a cylinder Cyin stopping in an intake stroke, against the piston stop position Pin of the cylinder Cyin, and specifies the amount of fuel Q1 corresponding to the detected piston stop position Pin of the cylinder Cyin (step S220). The automatic engine restart control then controls an injector to inject the specified amount of fuel Q1 into an intake port of the cylinder Cyin (step S230). Under the condition that the piston stop position Pin of the cylinder Cyin suggests low gas intake performance, the increased amount of fuel Q1 is injected into the intake port of the cylinder Cyin. This arrangement desirably reduces a misfire rate at the timing of first combustion and thereby improves the startability of an engine.

Abstract: A method for determining composition of a fuel blend from a first and at least a second fuel for operating an internal combustion engine. An ignition angle of the internal combustion engine is altered and a non-intermittent fluctuation in torque, which is a function of ignition angle, and/or a non-intermittent rotational discontinuity, and/or a variable derived from the discontinuity is used as a parameter for determining the composition of the fuel blend.

Abstract: An internal combustion engine has a plurality of cylinders and an exhaust tract into which a mixture which is situated in the respective cylinder is introduced in the respective discharge strokes. A combustion misfire rate is determined as a function of at least one operating variable of the internal combustion engine. A temperature in the exhaust tract is determined as a function of the combustion misfire rate.

Abstract: A failure diagnosis apparatus for a vehicle is disclosed. The apparatus includes a diagnosis processing section for executing failure diagnosis processing on a device of the vehicle to generate a diagnosis result. The apparatus also includes a data managing section for managing data of the diagnosis result. After an execution condition is met for failure diagnosis, the diagnosis processing section outputs an execution demand to the data managing section for the failure diagnosis processing. In response to the execution demand, the data managing section outputs an execution permission to the diagnosis processing section for the failure diagnosis processing. Also, after the execution condition is met for the failure diagnosis, the diagnosis processing section starts executing the failure diagnosis processing regardless of whether the execution permission has been outputted by the data managing section. A method of failure diagnosis is also disclosed.

Abstract: An electronic control device according to the invention is disclosed for controlling the internal combustion engine in a motor vehicle, for fault recognition with an irregular running determination unit and with an injection quantity correction unit, a defined group of cylinders being associated with a lambda probe, the injection quantity of a cylinder to be investigated of the defined group is adjusted in the direction of lean by a differential adjustment value associated with an irregular running differential value, and the injection value of at least one of the remaining cylinders, which are associated with the same lambda probe, is correspondingly adjusted in the direction of rich, so that in total a predetermined lambda value of this group of at least approximately 1 is reached. Homogeneous operation is thus ensured. The differential adjustment values may, for example, relate to the injection quantity itself, the injector stroke or the injection time.

Abstract: A system and method for selecting the data content of an ionization feedback signal is disclosed. An ignition system monitors both the ionization signal and ignition coil dwell data. The ignition system outputs either the ionization signal or the ignition coil dwell data on the ionization feedback line, depending on what information is desired by the powertrain control module. In one embodiment, the ionization signal is only output during the before ignition period when the operating condition of the engine indicates possible pre-ignition conditions.

Abstract: An ignition apparatus which allows for an accurate diagnosis of a spark plug in an internal combustion engine provided with plural spark plugs for each cylinder is provided for an internal combustion engine. The ignition apparatus is for an internal combustion engine provided with plural spark plugs for each cylinder, and includes an input port which receives fail signals S3 and S4 generated corresponding to each of the plural spark plugs for diagnosis of the spark plugs. An input timing of the fail signal to the input port is made different for each of the plural fail signals. Ignition timings S1, S2 of the plural spark plugs are set to different times.

Abstract: In an internal combustion engine including a flywheel damper, an operation range in which misfire detection is affected by the flywheel damper is set in advance. Whether or not an operation state of the internal combustion engine is within an operation range affected by the flywheel damper is determined. When the operation state is within the operation range affected by the flywheel damper, for example a cylinder specifying process specifying a misfiring cylinder is stopped. By such processing, erroneous detection attributed to irregular rotation fluctuation behavior caused by the flywheel damper can be avoided, and misfire detection performance can be improved.

Abstract: An ignition apparatus which allows for an accurate diagnosis of a spark plug in an internal combustion engine provided with plural spark plugs for each cylinder is provided for an internal combustion engine. The ignition apparatus is for an internal combustion engine provided with plural spark plugs for each cylinder, and includes an input port which receives fail signals S3 and S4 generated corresponding to each of the plural spark plugs for diagnosis of the spark plugs. An input timing of the fail signal to the input port is made different for each of the plural fail signals. Ignition timings S1, S2 of the plural spark plugs are set to different times.

Abstract: Provided is an engine control apparatus equipped with a three-way catalyst for purifying exhaust gas, a unit for calculating an operational state based on outputs from various sensors, a unit for calculating a fuel injection amount, a unit for driving an injector, a unit for calculating an actual misfire ratio, a catalyst damage determining misfire ratio calculating unit for calculating a misfire determining ratio, a catalyst damaging misfire determining unit for cutting off a supply of fuel when it is determined that a damage-causing misfire state has arisen, a unit for storing an actual misfire ratio at a time when it is determined that the damage-causing misfire state has arisen, and a unit for making a recovery from the cutoff of the fuel supply when the misfire determining ratio has become larger than the misfire ratio at the time of the determination that the damage-causing misfire state has arisen.

Abstract: The invention relates to a method for determining the composition of a fuel blend from a first and at least a second fuel for operating an internal combustion engine. The method makes provision for the ignition angle of the internal combustion engine to be altered and for a non-intermittent fluctuation in the torque, which is a function of the ignition angle, and/or a non-intermittent rotational discontinuity and/or a variable derived from said discontinuity to be used as the parameter for determining the composition of the fuel blend. The degree of efficiency of an internal combustion engine is a function of the ignition angle. It is known that the optimal ignition angle is a function of the composition of the fuel blend. Furthermore, fuel blends which have different compositions have a different knocking limit. The knocking limit thereby denotes the ignition angle, whereat a predetermined quantity of knocking combustion occurs.

Abstract: A system and method for pre-processing an ionization signal to amplify knock information and combining the amplified knock information with the ionization signal to create a knock-enhanced ionization signal is disclosed. In one embodiment, an on-plug integrated ionization detection circuit detects the ionization signal, processes the ionization signal to produce a knock-amplified ionization signal and then combines the original ionization signal with the knock-amplified ionization signal to create a knock-enhanced ionization signal. The step of processing the ionization signal to produce a knock-amplified ionization signal may comprise any singular step, or combination, of amplifying, band-pass filtering, AC-coupling, and offsetting said in-cylinder ionization signal.

Abstract: An ignition device, including: an ignition coil (1) having a primary coil and a secondary coil; a switching element (5) for causing a primary current to be conducted through and shut off from the primary coil of the ignition coil; a waveform shaping circuit (6) for shaping a waveform of an ignition signal transmitted from an outside through a signal line to supply a conduction signal thus obtained to the switching element; ion current detecting means (8, 9) connected to the secondary coil of the ignition coil, for detecting an ion current flowing through the secondary coil; and ion signal generating means (10, 11, 12) for outputting an ion signal, which indicates the ion current detected for a predetermined period after the conduction signal of the waveform shaping circuit has been turned off, to the outside through the signal line while invalidating the conduction signal from the waveform shaping circuit.

Abstract: A method of determining current detection circuit failure determines failure of a current detection circuit that is connected to positive and negative sides of a power source and that issues a voltage corresponding to detected current at an output terminal. The method of determining failure cuts-off either one of the current detection circuit connections to the positive and negative sides of the power source, detects output voltage from the output terminal, and determines proper operation or failure of the current detection circuit.

Abstract: Presented is a device that provides a correction factor to compensate for varying fuel and air properties in an ion signal sensed in combustion chamber of reciprocating and continuous combustion engines, on a predetermined basis during the combustion of conventional petroleum-based fuels, other alternate fuels, and renewable fuels. The device uses an ion current reference sensor device and a processing module to provide a correction factor to the ion signal(s). The ion current reference sensor device is positioned near the chamber(s) of the engine and fuel provided to the chamber(s) is routed to provide a diffusion flame and the resultant ion current from the flame is measured and provided to the processing module at discrete intervals during the combustion process. Alternatively, a pre-mixed flame is used. The processing module provides a scaling factor to be applied to the ion signal and/or calibration points used to detect combustion conditions.

Abstract: A system for determining a minimum ignition coil charge duration of an internal combustion engine to meet a desired level of combustion stability includes a sensor in communication with a controller. The sensor is configured to measure the ionization current of a cylinder of the internal combustion engine and output to the dwell controller. The controller is configured to determine a combustion stability criterion based upon the ionization signal and determine the minimum ignition coil charge duration based upon the combustion stability criterion.

Abstract: A misfire detector prevents catalysts from being heated to damaging high temperatures. The misfire detector for a multi-cylinder engine includes a fuel cut control to stop supplying fuel to misfiring cylinders, a control to prevent a fuel feed back control and a fuel learning control and to initialize the correction values of both the fuel feed back control and the fuel learning control, and a retard control to retard the ignition timing based on the extent that misfire occurs or the air-fuel ratio. The retard control can be replaced by a throttle opening control for misfire to limit the throttle opening angle. The retard control can also be replaced by an engine or vehicle speed control to limit the engine or vehicle speed below a predetermined engine or vehicle speed, respectively, irrespective of the throttle position.

Abstract: This feature of the present invention comprises a system and method of controlling exhaust gas recirculation (EGR) based on a measure combustion stability measure. The combustion stability measure is obtained by determining the integration duration of the engine ionization signal, i.e., the crank angle at which the integral of the ionization signal reaches a specified percentage of its total. The present invention uses the integration duration to control the maximum EGR rate of the engine in a closed loop while maintaining the combustion stability of an internal combustion engine.

Abstract: A cylinder misfire control system for a displacement on demand (DOD) engine that is operable in an activated mode and a deactivated mode includes a sensor that is responsive to rotation of a crankshaft of the engine and a first module that calculates a time derivative based on a first time period associated with a first deactivated cylinder and a second time period associated with a second deactivated cylinder. The first and second time periods are based on the rotation of the crankshaft. A second module detects a misfire occurrence in an activated cylinder based on the time period derivative.

Abstract: This feature of the present invention comprises an ignition diagnostics and feedback control system based upon detected ionization current in an individual cylinder. The system is divided into two subsystems: an ignition diagnostics subsystem and an ignition feedback control system subsystem. The ignition diagnostics subsystem comprises an ignition system diagnostics, a misfire detector, a knock detector, and a robust multi-criteria minimum timing for best torque MBT timing estimator. The ionization feedback control subsystem comprises five main subsystems: a closed loop cold start retard spark control using ionization feedback, a closed loop MBT timing control using ionization feedback, a closed-loop individual cylinder air to fuel ratio balancing control system, an optimal wide open throttle air/fuel ratio control, and an exhaust gas control using a spark plug ionization signal.

Abstract: This feature of the present invention comprises a method and apparatus to retard the spark time. As a result, the catalyst heats up quickly during the cold start. The retard spark control method of the present invention uses a closed loop to adjust the engine retard limit during an engine cold start to retard the engine spark as much as possible without engine misfire and with minimum partial burn. The increased exhaust temperature heats up the catalyst more quickly than conventional open loop approaches, which as a result, reduces hydrocarbon emissions. The closed loop retard spark control using ionization current feedback consists of four major components or functions, an error and gain generator, a proportional and integration control processing block, a default spark timing processor, and an adaptive learning apparatus.

Abstract: The present feature of the invention is generally directed to a subsystem of an ignition diagnostics and feedback control system using ionization current feedback. It utilizes the ionization signal from an ionization detection circuit to monitor ignition parameters, such as primary charge timing, primary charge duration, ignition/spark timing, and ignition/spark duration for future “smart” ignition system control. In addition, the ionization signal is also used to detect spark plug carbon fouling, as well as plug insulator overheating. These parameters can be monitored for every cylinder of the engine for each engine cycle.

Abstract: In a method for reducing NOx in the exhaust gas of an externally ignited, explosion-type internal combustion engine that is operated at a lean fuel/air ratio of ?>1 and has a motor control device for controlling ?, the ? value is slidingly controlled as a function of an average mass temperature in the combustion chamber of the externally ignited, explosion-type internal combustion engine, wherein for a low average mass temperature ? is decreased and for a high average mass temperature ? is increased such that the internal combustion engine is operated in any operational state close to the misfiring limit, and thereby, with the most minimal NOx emission possible.

Abstract: A misfire detection apparatus of an internal combustion engine for detecting combustion or a misfire of an air fuel mixture in the internal combustion engine based on an ion current generated at the combustion time of the air fuel mixture. The misfire detection apparatus includes ion current detection means and misfire determination means. The ion current detection means detects the ion current responsive to the amount of ions occurring in a cylinder just after combustion of the air fuel mixture in the cylinder in the internal combustion engine. The misfire determination means calculates a predetermined function based on the ion current detection value and determines that the condition is combustion when the magnitude exceeds a threshold value.

Abstract: A misfire detector is provided that is accurate even in the case of a disturbance due to causes such as driving on a rough road. The misfire detector is equipped with a crankshaft revolution detector to measure the time period required for the crankshaft of an internal-combustion engine to revolve for a given angle. A signal-processor is also provided for detecting the misfiring of the internal-combustion engine by processing the time period. In one embodiment, the misfire detector has two filters having the same sensitivity to the misfire frequency, and differing in the sensitivity to frequencies adjacent to said misfire frequency. It can be determined that a misfire has occurred if the ratio or difference between the outputs of the two filters stays within a fixed range and one or both of the filters have respective outputs exceeding a threshold value.

Abstract: A system and method for operating a combustion engine including a combustion chamber operable in at least a first operating mode and second operating mode. An engine control unit (ECU) performs conductivity sensing within the combustion chamber and interprets the results. Specifically, the ECU determines the current between a pair of spark plug electrodes placed within a combustion chamber of a combustion engine prior to, or after, combustion. The ECU determines whether the current between the pair of electrodes is indicative of spark plug fouling. If spark plug fouling is determined, the ECU can modify the mode of operation to correct the spark plug fouling and clean the deposits on the spark plug while the engine is in operation and without operation intervention.

Abstract: A method for detecting combustion misses in a multi-cylinder internal combustion engine. The control units of the engine use an engine control program which is interrupted by interrupt routines, in phase-synchronism with the rotational movement of the crankshaft, in which at least the data required for injection and firing are processed. The detection of combustion misses includes establishing and evaluating crankshaft segment times in which the crankshaft covers an associated circle-segment angle range. The crankshaft segment are also established and evaluated in particular interrupt routines, and for the further subset of cylinders in the interrupt routines in which their firing is controlled. Furthermore, the crankshaft segment times for the first cylinder is established and evaluated in certain additionally generated interrupt routines.

Abstract: Methods and systems for cutting off the supply of fuel to an engine in response to engine turn-off. A fuel cutoff solenoid or functionally equivalent device is connected to a source of electrical power in response to detection of conditions representing engine turn-off. One method for cutting off the supply of fuel to the engine comprises the following steps: detecting whether ignition pulses are present; and then activating a device for cutting off the supply of fuel to the engine in response to detecting the cessation of ignition pulses. The fuel cutoff device is activated by connecting it to either a battery or an output of a generator being driven by the engine. In the latter case, the rotor is grounded and a bipolar transistor is bypassed in response to detection of conditions representing engine turn-off.

Abstract: An apparatus diagnoses and controls combustion of an internal combustion engine which makes smooth operation of an engine possible by adjusting the combustion condition at the occurrence of knock, misfire, and flame quenching and also makes it possible to detect the occurrence of abnormality in cylinder pressure detectors without delay and deal with the abnormality without stopping the operation of the engine. A maximum pressure ratio Pp/P0 is calculated, Pp being the maximum cylinder pressure and P0 being the compression pressure at one or a plurality of crank angles in the compression stroke Pp/P0 is compared with pressure ratios for each diagnosis category, the combustion conditions are diagnosed by judging the result of the comparison every cycle or plural cycles.

Abstract: Methods and apparatus are provided for sensing a misfire in an engine having at least one cylinder and for providing a misfire indication signal in response to the occurrence of the misfire. The apparatus comprises an electronic controller that calculates an expected time period for a cylinder event during which fuel is combusted in a cylinder to provide an expected time period value. The time period of the cylinder event is measured to provide a measured time period value. The difference between the expected time period value and the measured time period value is calculated to provide a difference time period value. The difference time period value is compared to a predetermined threshold time. The misfire indication signal is provided in response to the difference time period value exceeding the predetermined threshold time.

Abstract: An apparatus and method to detect abnormal combustion conditions for use as a feedback control of a lean burn reciprocating engine using ionization signals is presented. The system receives a succession of ionization signals for successive cycles of a running engine and processes a plurality of related ionization signals for signal stability. The ionization signals are checked to determine if an abnormal combustion condition such as knock or misfire has occurred. The variation of an ionization signal that changes with respect to an engine parameter over a combustion event of the lean burn reciprocating engine operating with an air to fuel ratio corresponding to a lambda (&lgr;) greater than 1.4 is measured and a floating bounded space is associated with the ionization signal. An indication that the abnormal combustion condition has been detected is provided if a portion of the ionization signal is within the floating bounded space.