Abstract: An ignition system controlled by a powertrain controller via a dwell line carrying a dwell signal has a state machine to monitor a dwell period between consecutive dwell signals and to adjust a rate of a variable clock signal accordingly. A multi-bit counter is clocked by the adjusted clock signal. The counter has a first set of bits to establish an integration period and a second set of bits coupled to a resistive ladder generating a stair step signal. A current sensor provides a current signal proportional to the ion current. A comparator compares the current signal to the stair step signal. An ion current counter is incremented during the integration period whenever the current signal indicates an ion current magnitude greater than the stair step signal. The accumulated count at the end of the integration period is reported to the powertrain controller as a measure of the ion current.

Abstract: An apparatus for measuring the loss factor of an insulator for medium or high voltages is equipped with a tap adapter forming a point for picking up an electrical signal, and comprises a reference capacitor having a first electrode connected to the tap adapter and a second electrode; a first voltage detection module is connected to the first electrode of the reference capacitor for detecting a signal representative of the voltage applied to the reference capacitor; an active electronic device is connected to earth and to the second electrode of the reference capacitor for keeping the potential of the second electrode at a predetermined reference value; a second voltage detection module is connected to an output of the active electronic device in order to detect a signal representative of the electric current that flows through the reference capacitor.

Abstract: In order to solve a problem that in an internal combustion engine in which abnormal combustion (knocking or an accidental fire) of an engine is detected from an ion signal, the setting of an abnormal combustion determination threshold value under a transient condition in which an engine operating state abruptly changes is difficult to thereby cause erroneous determination, the present invention is an engine control device provided with an ion signal detection means for detecting ions generated during combustion, and provided with an abnormal combustion determination means for determining knocking or an accidental tire according to an ion signal detected by the detection means, the engine control device being characterized by being provided with an in-cylinder temperature estimation means for estimating the in-cylinder temperature in a normal combustion cycle under a current operating condition of the engine, and by setting the knocking determination threshold value or accidental fire determination threshold v

Abstract: The present invention relates to a device for analyzing a cylinder wise performance of an internal combustion engine, comprising ion current measurement means that are arranged to measure an ion current in a engine and that are also arranged to produce a first signal corresponding to a measurement performed by said ion current measurement means, and also comprising an amplifier that is connected to said ion current measurement means and that is arranged to receive and amplify said first signal in order to produce an amplified signal, and further also comprising first analyzing means for analyzing said amplified signal for detecting an indication of a knock event in the engine, wherein said amplifier is a variable-gain amplifier and that said device further comprises second analysis means that is arranged to receive and analyze said amplified signal and to adjust a gain of said amplifier. The invention also relates to a method for analyzing a performance of a engine.

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: Provided is a failure diagnosis system which can diagnose whether or not a sensitivity adjustment part is in failure. The failure diagnosis system includes: a plurality of sensors; various sensors that detect operating conditions of a device; a plurality of sensitivity adjustment parts that adjust receiver sensitivities of sensor signals from the plurality of sensors based on the detected operating conditions; and a failure diagnosis part that diagnoses whether or not the plurality of sensitivity adjustment parts are in failure. The failure diagnosis part detects a failure condition of a sensitivity adjustment part when a difference between a comparison value calculated based on a maximum value of the adjusted sensor signals from the plurality of sensitivity adjustment parts at a given interval, and a maximum value of the adjusted sensor signal from the sensitivity adjustment part to be diagnosed at the given interval is larger than a given amount.

Abstract: A self charging ion current sensing circuit is provided. The self charging ion current sensing circuit is coupled to spark generation circuitry, and utilizes the spark plug electrodes as the ion current sensing electrodes. The self charging is achieved by utilizing the spark current during an ignition event to charge an ion bias capacitor. After the ignition event, the charge voltage build up on the ion bias capacitor is used to provide an ion current across the spark plug gap. The ion current is passed through an offset stage that translates the ion current sense voltage to a voltage that can be buffered and amplified from a single power source available in automotive and vehicular applications. The output of the circuit provides tri-state information, including spark current, null current, and linear representation of ion sense current.

Abstract: A device for directing combustion anomalies of an internal combustion engine, comprising at least one power supply, at least one ion current amplifier, at least one signal filter, at least one ion current signal output, at least one ignition coil actuating electronic system, at least one ignition coil, at least one ion current adapter, and at least one ion current sensor.

Abstract: An automatic variable gain amplifier is provided. The automatic variable gain amplifier automatically adjusts the amplification of a signal, and in one embodiment, an ion signal, based on the amplitude of the peaks of the signal. The automatic variable gain amplifier detects the peaks of the signal, compares them to a threshold value, and, based on this comparison, varies the amount by which the signal is amplified. The automatic variable gain amplifier produces a composite output waveform for an input waveform with an amplitude that may vary over a plurality of orders of magnitude.

Abstract: The present invention relates to a device for analysing a cylinder wise performance of an internal combustion engine, comprising ion current measurement means that are arranged to measure an ion current in a engine and that are also arranged to produce a first signal corresponding to a measurement performed by said ion current measurement means, and also comprising an amplifier that is connected to said ion current measurement means and that is arranged to receive and amplify said first signal in order to produce an amplified signal, and further also comprising first analysing means for analysing said amplified signal for detecting an indication of a knock event in the engine, wherein said amplifier is a variable-gain amplifier and that said device further comprises second analysis means that is arranged to receive and analyse said amplified signal and to adjust a gain of said amplifier. The invention also relates to a method for analysing a performance of a engine.

Abstract: A combustion state detection apparatus includes an ion detection device that detects ions generated in a combustion chamber, an end detection device that detects ion signal end timing after spark timing obtained from the ion detection device, and a combustion diagnosis device that sets comparative timing to be compared with the end timing to determine abnormal combustion when the end timing is advanced from the comparative timing. The diagnosis device sets a smoothed value smoothed using various ion signal end timing values to set a ratio of the smoothed value and the spark timing and sets the comparative timing by making the ratio variable at predetermined timing with respect to the smoothed value. Hence, abnormal combustion in the internal combustion engine can be detected without causing a change in detection accuracy even with a change in calibration or environment and matching man hours for abnormal combustion detection can be reduced.

Abstract: An ion-based triple sensor is disclosed. The ion-based triple sensor may include an ion sensing unit, configured to measure an ionic current intensity, a pressure sensing unit, configured to measure a pressure, and a temperature sensing unit, configured to measure a temperature. The ion-based triple sensor may further include a signal processing unit coupled to the ion sensing unit, the pressure sensing unit and the temperature sensing unit. The signal processing unit may include a filtering component, configured to filter at least one of the ion, pressure and temperature measurements, and a data acquisition component, configured to sample the filtered measurements and communicate the samples to a controller.

Abstract: The present invention falls into the field of methods and devices for identifying the various phases of the ionization current during combustion in a cylinder of an internal combustion engine. The present invention develops over various phases comprising the measurement of the ionization current signal and the sampling of the signal within predetermined windows, with the subsequent identification of the sample signal which is preceded by a signal whose derivative has a positive value and followed by a signal whose derivative has a negative value.

Abstract: The present invention is an operation control method on the basis of an ion current in an internal combustion engine, the method comprising a step of detecting the ion current generated within a combustion chamber 30 so as to control an operating state of the internal combustion engine 100 on the basis of a state of the detected ion current, wherein a control at an engine start point in time on the basis of the state of the ion current is stopped for predetermined cycles just after the engine start.

Abstract: Alcohol concentration level of flex fuel is estimated based upon in-cylinder ionization signals. The in-cylinder ionization signals are integrated and the rotational completion point of a chosen percentage of the integration total is identified as the integration location for the operating conditions under observation. The calculated integration location correlates with alcohol concentration level of flex fuel, and the integration calculations provide a basis for a virtual flex fuel sensor that provides calculated estimates of alcohol concentration rather than direct sensing using an expensive physical flex fuel sensor.

Abstract: There is provided an ignition diagnosis apparatus that detects ignition abnormality in a multi-point-ignition internal combustion engine.

Abstract: A device for directing combustion anomalies of an internal combustion engine, comprising at least one power supply, at least one ion current amplifier, at least one signal filter, at least one ion current signal output, at least one ignition coil actuating electronic system, at least one ignition coil, at least one ion current adapter, and at least one ion current sensor.

Abstract: A combustion state detection apparatus for an internal combustion engine, includes convexity detection means (30) for detecting that domain within the detection interval in which the change shape of the ionic current is upwardly convex, on the basis of the ionic current data extracted by data extraction means (20), and preignition decision means (40) including comparison setting means for setting a comparison value with which the upwardly convex domain is compared, and functioning to decide the occurrence of the preignition or the premonitory phenomenon thereof when the upwardly convex domain lies at a timing earlier than the comparison value, wherein the convexity detection means (30) includes leak current judgment means for judging the appearance of a leak current across electrodes, and it enables the detection of the upwardly convex domain when the appearance of the leak current has been judged.

Abstract: A knock detection apparatus for an internal combustion engine can accurately detect the occurrence of a knock without an influence of a noise component even if the noise component having the same frequency as a knock vibration superposes on an ionic current signal. The apparatus includes an ionic current detection section, a knock signal detection section for detecting a knock signal based on an ionic current, a crank angle sensor for detecting a crank angle corresponding to a rotational position of the engine, a window setting section for setting a noise detection window, a noise component detection section for detecting a noise component in the window, and a knock determination section for determining the occurrence of a knock based on a relation between the noise component and the knock signal. The window setting section sets the window after a predetermined crank angle corresponding to an end of a combustion stroke of the engine.

Abstract: A specific electrode arrangement for a burner already exists with which the flame of the burner is influenced by using electrical fields, whereby these electrical fields pass through only areas of the flame in which a stabilizing and pollutant-reducing action occurs. According to at least one embodiment of the invention, the electrodes used to this end simultaneously serve both as probes for detecting flame properties as well as active field electrodes for influencing the flame properties. The probe signals can react to the voltage applied in an inertia-free manner to the electrodes without the involvement of mechanical elements. According to the associated device equipped with a burner and associated electrodes and with a power supply unit, the power supply unit furnishes a voltage that varies over time, and at least one measuring transducer exists that detects the current generated in the flame by the voltage between both electrodes and provides feedback to the power supply unit after amplification.

Abstract: An internal-combustion-engine combustion condition detection apparatus is provided with an ignition means that makes an ignition plug ignite a fuel; an ignition control means that controls the operation of the ignition means; an ion-current detection means that detects an ion current generated; an ion current detection range setting means that sets an ion-current detection range; a preignition detection means that detects preignition within a detection range to be set; a leakage current detection range setting means that sets a leakage-current detection range; and a leakage current determination means that determines whether or not a smolder exists, based on a current detected, within a detection range to be set, by the ion-current detection means. The ignition control means includes a non-combustion-stroke ignition control means; the leakage-current detection range set by the leakage current detection range setting means is set within the non-combustion stroke.

Abstract: The present invention falls into the field of methods and devices for identifying the various phases of the ionization current during combustion in a cylinder of an internal combustion engine. The present invention develops over various phases comprising the measurement of the ionization current signal and the sampling of said signal within predetermined windows, with the subsequent identification of the sample signal which is preceded by a signal whose derivative has a positive value and followed by a signal whose derivative has a negative value.

Abstract: An internal-combustion-engine combustion condition detection apparatus is provided with an ignition means that makes an ignition plug ignite a fuel; an ignition control means that controls the operation of the ignition means; an ion-current detection means that detects an ion current generated; an ion current detection range setting means that sets an ion-current detection range; a preignition detection means that detects preignition within a detection range to be set; a leakage current detection range setting means that sets a leakage-current detection range; and a leakage current determination means that determines whether or not a smolder exists, based on a current detected, within a detection range to be set, by the ion-current detection means. The ignition control means includes a non-combustion-stroke ignition control means; the leakage-current detection range set by the leakage current detection range setting means is set within the non-combustion stroke.

Abstract: An ion-based triple sensor is disclosed. The ion-based triple sensor may include an ion sensing unit, configured to measure an ionic current intensity, a pressure sensing unit, configured to measure a pressure, and a temperature sensing unit, configured to measure a temperature. The ion-based triple sensor may further include a signal processing unit coupled to the ion sensing unit, the pressure sensing unit and the temperature sensing unit. The signal processing unit may include a filtering component, configured to filter at least one of the ion, pressure and temperature measurements, and a data acquisition component, configured to sample the filtered measurements and communicate the samples to a controller.

Abstract: An engine control system enables engine control to cause ignition timing to approximate MBT without necessarily measuring torque and combustion pressure. The negative ion current in an engine combustion chamber is measured and a first crank angle B corresponding to a first rate in change of the negative ion current curve E is identified. A second crank angle C corresponding to a second rate in change of the negative ion current curve E also is identified. The ignition timing is controlled based upon a third crank angle G that generally is a midpoint between the first crank angle B and the second crank angle C. The third crank angle G becomes a specified target crank angle.

Abstract: An ion-based triple sensor is disclosed. The ion-based triple sensor may include an ion sensing unit, configured to measure an ionic current intensity, a pressure sensing unit, configured to measure a pressure, and a temperature sensing unit, configured to measure a temperature. The ion-based triple sensor may further include a signal processing unit coupled to the ion sensing unit, the pressure sensing unit and the temperature sensing unit. The signal processing unit may include a filtering component, configured to filter at least one of the ion, pressure and temperature measurements, and a data acquisition component, configured to sample the filtered measurements and communicate the samples to a controller.

Abstract: A cylinder head gasket, interposed between a cylinder head and a cylinder block in an engine, comprises a thin metal plate having a thickness between 0.1 and 2.0 mm, and elastic insulating sheets placed on both surfaces of the thin metal plate and each having a thickness between 0.01 and 0.5 mm, in which: created is a portion at which the thin metal plate is exposed at an inner edge side extending from an inner side of the cylinder block; and also created is an extension portion extending from the cylinder block at an outer edge side extending from an outer side of the cylinder block. Also created is a combustion state detector for detecting a combustion state of an engine, wherein the cylinder head gasket is interposed between the cylinder head and the cylinder block in the engine, the portion at which the thin metal plate is exposed is at the extension portion of the cylinder head gasket, and a signal detecting device is connected thereto.

Abstract: An ion-based triple sensor is disclosed. The ion-based triple sensor may include an ion sensing unit, configured to measure an ionic current intensity, a pressure sensing unit, configured to measure a pressure, and a temperature sensing unit, configured to measure a temperature. The ion-based triple sensor may further include a signal processing unit coupled to the ion sensing unit, the pressure sensing unit and the temperature sensing unit. The signal processing unit may include a filtering component, configured to filter at least one of the ion, pressure and temperature measurements, and a data acquisition component, configured to sample the filtered measurements and communicate the samples to a controller.

Abstract: A system for measuring in-cylinder parameters utilizing an image charge measured in an engine cylinder by an in-cylinder pressure sensor due to chemi and or thermal ionization in Engine. The in-cylinder pressure sensor includes a sensing element, which is a metal sensor probe with a selective coating (e.g., metal, oxides of metal, native oxides, semiconductor, oxides of semiconductors, ceramics, glass, dielectric, etc., in the form of a coating on the metallic probe, tube, etc) in order to function in harsh, corrosive and/or elevated temperature environments. The output of the sensor can be connected to a signal-conditioning unit, which includes a low noise differential charge amplifier with an auto offset correction circuit to measure fast varying signals. The signal out from the conditioning unit can be acquired utilizing a high-speed microcontroller-based data acquisition system with suitable software to analyze and estimate parameters such as, for example, in cylinder pressure and knocking.

Abstract: The present invention is an operation control method on the basis of an ion current in an internal combustion engine, the method comprising a step of detecting the ion current generated within a combustion chamber 30 so as to control an operating state of the internal combustion engine 100 on the basis of a state of the detected ion current, wherein a control at an engine start point in time on the basis of the state of the ion current is stopped for predetermined cycles just after the engine start.

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: A method of real-time estimation of indicators of the engine combustion state from signals containing oscillating components. A signal, such as a vibration signal for example, correlated with the engine combustion, is acquired as a function of time or of the crank angle. Real-time filtering and time-frequency analysis of this signal is carried out and indicators of the combustion state are estimated in real time from this analysis. The method has application for combustion control of an internal-combustion engine.

Abstract: An ion sensing arrangement for a small internal combustion engine includes an ion sensor placed in the engine's combustion chamber to measure the conductivity of the combusted fuel-air mixture. Scaling circuitry, such as variable voltage divider circuitry, is connected to be in electrical communication with an output of the ion sensor. The scaling circuitry operates to adjust the output signal to a value appropriate for measurement. Preferably, the scaling circuitry adjusts the output signal based on a comparison with a reference value.

Abstract: The present invention is a combustion state determination method of an internal combustion engine for detecting an ion current which is generated in a combustion chamber at combustion of the internal combustion engine in a detection period to determine a combustion state, comprising steps of detecting a primary combustion period on the basis of a first ion current which forms the detected ion current and occurs immediately after ignition, detecting a secondary combustion period on the basis of the ion current which occurs after disappearance of the first ion current when at least the detected primary combustion period is normal, determining the combustion state on the basis of the detected primary combustion period when the secondary combustion period is smaller than a predetermined value, and determining the combustion state on the basis of a whole combustion period from start of the detection period of the ion current to end of the last secondary combustion period in the detection period when the secondary

Abstract: A knock control apparatus for an internal combustion engine can avoid an incorrect knock determination thereby to prevent output power reduction and suppress knocks occurring in succession. A knock detection section outputs a knock detection signal based on an ionic current, and a threshold setting section sets a knock determination threshold. A knock determination section determines the occurrence of a knock based on the threshold and the knock detection signal. A required correction amount setting section sets a required correction amount for ignition timing based on a knock determination result, and a control parameter correction section corrects ignition timing based on the required correction amount. A noise determination section determines the occurrence of noise based on whether said knock detection signal or said control parameter correction amount is within a set level range, and a noise removal period setting section sets a noise removal period based on the noise determination result.

Abstract: A knock detection apparatus for an internal combustion engine can accurately detect the occurrence of a knock without an influence of a noise component even if the noise component having the same frequency as a knock vibration superposes on an ionic current signal. The apparatus includes an ionic current detection section, a knock signal detection section for detecting a knock signal based on an ionic current, a crank angle sensor for detecting a crank angle corresponding to a rotational position of the engine, a window setting section for setting a noise detection window, a noise component detection section for detecting a noise component in the window, and a knock determination section for determining the occurrence of a knock based on a relation between the noise component and the knock signal. The window setting section sets the window after a predetermined crank angle corresponding to an end of a combustion stroke of the engine.

Abstract: A driver circuit is described for an ion measuring device associated with a cylinder of a diesel engine for the measurement of the conductivity of the combustion gas present in the cylinder, wherein a negative voltage can be applied by the driver circuit to a glow plug serving as a sensor and associated with the cylinder for a respective ion measurement. The negative voltage is generated by a capacitor which is correspondingly charged each time the glow plug is switched off via the magnetic energy stored in the internal inductance of the glow plug.

Abstract: The present invention generally includes a method of detecting a misfire in an internal combustion engine. The method includes detecting a first engine speed at a first crankshaft position that corresponds to about a top dead center compression position of a first piston within a first cylinder and detecting a second engine speed at a second crankshaft position that corresponds to about a position subsequent to the top dead center compression position. The method determines whether the misfire occurred in the first cylinder based on the first engine speed and the second engine speed. The method provides an improved signal to noise ratio for engine misfire detection.

Abstract: A robust multi-criteria minimum timing for the best torque (MBT) timing estimation method and apparatus utilizes different ionization signal waveforms that are generated under different engine operating conditions. The MBT timing criteria is calculated based upon both ionization and analog derivative ionization. Multiple MBT timing criteria are determined and combined to increase the reliability and robustness of MBT timing estimation based upon spark plug ionization signal waveforms. In a preferred embodiment, a combination of the MBT timing estimation criteria comprises a maximum flame acceleration location, a 50% burn location, and a second peak location.

Abstract: The invention comprises a method to operate a direct-injection engine operative at various air/fuel ratios. The method comprises monitoring in-cylinder pressure, along with a corresponding engine crank position to periodically to determine instantaneous in-cylinder pressure states corresponding to the engine crank position during compression and expansion. Pressure ratios are determined based upon the instantaneous in-cylinder pressure states. A combustion heat release is determined based upon the pressure ratios. An aspect of the invention comprises extending the operation to diesel, diesel premixed and to HCCI engines.

Abstract: The ignition apparatus includes an electronic control unit and an igniter. The igniter detects ions resulting from ignition, and sends an ion current output signal to the electronic control unit. The igniter has a waveform shaping circuit and an ion current detecting/outputting circuit. The waveform shaping circuit is adapted such that a voltage at an input terminal thereof becomes higher than a predetermined reference voltage to turn the switching element ON when the ignition signal is caused to flow through an electric load. The ion current detecting/outputting circuit has an output terminal which is connected to the input terminal and outputs therefrom an ion current output signal obtained as a result of conversion of an ion current, and is adjusted such that the voltage at the input terminal at the time when the ion current output signal is outputted to the electronic control unit becomes lower than the reference voltage.

Abstract: An apparatus and method to sense the onset of combustion stability is presented. An electrode is positioned in a turbine combustion chamber such that the electrode is exposed to gases in the combustion chamber. The electrode may be integrated with an igniter. A control module applies a voltage potential to the electrode and detects a combustion ionization signal and determines if there is an oscillation in the combustion ionization signal indicative of the occurrence of combustion stability or the onset of combustion instability. The control module broadcasts a notice if the parameters indicate the combustion process is at the onset of combustion instability or broadcasts an alarm signal if the parameters indicate the combustion process is instable. Combustion parameters are adjusted to drive the combustion process towards stability.

Abstract: This feature of the present invention comprises a method, apparatus, and system for detecting and conditioning an ionization current signal. In one embodiment of the invention, an analog signal conditioning circuit detects and processes the ionization signal. The analog signal conditioning circuit uses a signal isolator having an input and an output, an amplifier having a first and a second input, and a first and a second output, wherein the first input operably connected to the signal isolator output, a peak detector having a first and a second input, and an output, wherein the first input is operably connected to the first output of the amplifier, and an integrator having a first and a second input, and an output, wherein the first input is operably connected to the second output of the amplifier.

Abstract: A knocking detection apparatus including: spark plugs disposed in cylinders of an internal combustion engine; an ion current detector for detecting ion currents flowing in the spark plugs; a time-frequency transformer for setting time intervals allowing one or more overlaps within a time from after ignition by the spark plugs to until the spark plug in the respective cylinder or in another cylinder next ignites and sampling ion currents in the respective time intervals to determine the time-frequency components of the ion current; a knocking detector for detecting knocking based on the time-frequency components; and a detection controller for inputting running status and controlling the time-frequency transformer and the knocking detector.

Abstract: Two embodiments of an integrated ionization detection circuit and ignition coil driver, an ASIC and a single electronic package, are disclosed. The apparatuses reduce the cost and complexity of an in-cylinder ionization detection system by combining like functionality into one ASIC or electronic module easing packaging constraints. In both embodiments, a current sink is used. The current sink removes noise in the form of voltage splices. The voltage spikes are high voltage, but of short duration. The current sink prevents these spikes from turning on the IGBT. However, the current sink allows the IGBT command signal to pass. This device also comprises a switch whereby ionization current and coil primary current are multiplexed.

Abstract: A misfire detection apparatus of an internal combustion engine. The misfire detection apparatus includes an angle sensor for detecting rotation angle of the internal combustion engine, an ECU for performing fuel injection and ignition control based on rotation information of the angle sensor, an ignition coil for generating a high voltage for ignition based on a drive signal from the ECU, and an spark plug, as the high voltage for ignition of the ignition coil is applied, for generating an ignition spark and igniting an air fuel mixture. The misfire detection apparatus applies a bias voltage to the spark plug, detects an ion current, makes a misfire determination based on the ion current detection, and makes a failure determination based on time change of rotation information of the internal combustion engine when misfires occur successively in a specific cylinder of the internal combustion engine.

Abstract: The present feature of the invention comprises a method and apparatus for determining cylinder ID. When a cylinder is compressed, the resistance increases across the spark plug gap. Thus, if a spark coil is only partially charged before activation of the spark, the air gap is not broken down and no ignition occurs in the cylinder in compression. The failure of a spark plug to spark is reflected in the ionization signal. In a preferred embodiment, the dwell time is selected so that the spark plug located in a cylinder that is not in compression will spark, while a spark plug in a cylinder that is in compression will not. The cylinder in compression will output an ionization signal with a shorter duration than a cylinder not in compression. In a preferred embodiment, two methods are used to calculate the duration of the spark, edge detection and integration.

Abstract: An apparatus and method to detect combustion conditions using ion signals for use in a feedback control of a diesel engine is presented. The apparatus is a spark plug type of sensor or a sensor integrated with a fuel injector. The spark plug type of sensor is used to provide a cold start mechanism combined with an ion sensing device.

Abstract: An apparatus and method to sense the onset of combustion stability is presented. An electrode is positioned in a turbine combustion chamber such that the electrode is exposed to gases in the combustion chamber. The electrode may be integrated with an igniter. A control module applies a voltage potential to the electrode and detects a combustion ionization signal and determines if there is an oscillation in the combustion ionization signal indicative of the occurrence of combustion stability or the onset of combustion instability. The control module broadcasts a notice if the parameters indicate the combustion process is at the onset of combustion instability or broadcasts an alarm signal if the parameters indicate the combustion process is instable. Combustion parameters are adjusted to drive the combustion process towards stability.

Abstract: In a first preferred embodiment, the present feature of the invention multiplexes both the ionization and driver current feedback signals into one signal, thus reducing cost and making coil packaging easier. The multiplexed signal first outputs the ionization detection signal and then replaces the ionization signal with the charge current feedback signal when the charge command Vin is enabled. In other words, the multiplexed feedback signal outputs the ionization feedback signal and switches to the charge current feedback signal when the charge command Vin is active. In a second preferred embodiment, the present feature of the invention comprises a method and apparatus to multiplex the ignition driver gate signal with both the ignition coil charge current feedback signal and the ionization signal, thus reducing the package pin count by two.