Abstract: A voltage transformer circuit is described for supplying a spark plug with ignition energy and for ionic current measurement. A transformer of the circuit generates a secondary voltage from a primary voltage and applies the secondary voltage to the spark plug to ignite an electric arc. Using a current effected by the secondary voltage, a capacitor is charged to a breakdown voltage of a Zener diode bridging the same, via a first branch, which leads from the transformer to a first of two sides of the capacitor. The primary voltage is disconnected from the transformer in order to extinguish the electric arc. The capacitor delivers charges for an ionic current via a second branch, which connects the second side of the capacitor to the transformer. A measuring signal of the ionic current is obtained by measuring a voltage drop at a measuring resistor.

Abstract: An ignition unit produces an ignition in a combustion chamber of a combustion engine in the following manner. The ignition unit comprises a radiofrequency resonator that radiates a plasma-creating radiofrequency field into the combustion chamber. The ignition unit further comprises a microwave resonator that radiates a plasma-boosting microwave field into the combustion chamber. In an embodiment, the microwave resonator has an output surface to which the combustion chamber is exposed when the ignition unit is fitted on the combustion engine. The radiofrequency resonator may comprise an electrode that is at least partially embedded in the microwave resonator. The electrode may have a tip that is located at a distance from the output surface so that the microwave resonator provides a barrier between the tip and the output surface.

Abstract: The invention relates to a method for operating a HF ignition system, wherein electrical energy for generating a corona discharge is fed with a voltage pulse into the HF ignition system and a series of measured values of an electrical variable is measured during the voltage pulse, and the measured values are evaluated in order to detect malfunctions. It is provided according to the invention that the measured values are evaluated by determining a characteristic variable for the fluctuation range of the same and comparing the determined characteristic variable with a threshold, or in that by means of a transformation of said series, the frequency spectrum of said series is calculated, and it is checked for at least one frequency range if a threshold is exceeded.

Abstract: A device for radiofrequency ignition of an internal combustion engine, including a power supply circuit including a transformer with a secondary winding connected to at least one resonator that has a resonant frequency in excess of 1 MHz and including two electrodes configured to generate a spark to initiate combustion of a combustible mixture in a cylinder of the engine in response to an ignition command. A measuring capacitor is connected in series between the secondary winding and the resonator, a measurement circuit measures a current at terminals of the measuring capacitor, the current providing an electrical image of how combustion is progressing, and a protection circuit is connected between the capacitor and the measurement circuit and is configured to spare the current measurement acquisition time from electrical effects caused by the ignition command.

Abstract: An ignition system (10) comprises a spark plug (12) having a first end (14) defining a spark gap (16) between a first electrode (18) and a second electrode (20). A transformer (46) comprises a primary winding 44 and a secondary winding (50) also forms part of the system. The secondary winding is connected in a secondary circuit to the first electrode 18 and the secondary winding has a resistance of less than 1K? and an inductance of less than 0.25 H. A drive circuit (26) is connected to the primary winding.

Abstract: A measuring device including: a supply circuit for radiofrequency ignition including a transformer including a secondary winding connected to at least one resonator having a resonance frequency higher than 1 MHz, and including two electrodes capable of generating a spark upon an ignition control; a measuring capacitor connected in series between the secondary winding and the resonator; a measuring circuit of ionization current of the combustion gases in a cylinder of the internal combustion engine associated with the resonator, the circuit being connected at terminals of the measuring capacitor; and/or a measuring circuit that measures a voltage at the resonator terminals upon an ignition control, the circuit being connected to terminals of the measuring capacitor.

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: The invention relates to the field of method and devices therefore for identifying which cylinder is in the compression phase in a gasoline indirect electronic injection internal combustion engine. The present invention develops over various phases, measuring the signal of the ionisation current of each cylinder in which the piston is located at the top dead centre, registering the average value thereof and comparing it with a predetermined value.

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: 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: A combustion state detecting apparatus for an internal combustion engine includes: an ignition plug (2) for generating a spark discharge for igniting an air-fuel mixture in a combustion chamber; an ignition coil (1) for supplying a high voltage to cause the ignition plug (2) to generate the spark discharge; and an ECU (3) for feeding a driving signal for driving the ignition coil (1). An electromotive force (secondary voltage) due to electromagnetic induction when a primary current is caused to flow through a primary winding of the ignition coil (1) in response to the driving signal from the ECU (3) is applied to the ignition plug (2) to detect an ion current generated in the combustion chamber to detect a combustion state in the ignition plug based thereon.

Abstract: Systems and methods for controlling an internal combustion engine include an ignition coil that generates a pre-discharge ionization signal during charging of the ignition coil after reaching a first threshold charge level and prior to spark discharge and a controller that determines an engine operating condition, such as pre-ignition or plug fouling, in response to the pre-discharge ionization signal. The ignition coil may also generate digital feedback and ionization signals used to by the controller for to control ignition coil dwell and repetitive sparking, as well as providing various combustion diagnostics.

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

Abstract: Disclosed is a way to detect ionization within a cylinder of an internal combustion engine where the engine selectively operates in either a spark ignition mode or a HCCI mode. A single ionization detector circuit adapts in response to a control input to alter its bias voltage and its gain to selectively enable effective detection of ionization for each of two different operational modes of an internal combustion engine.

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

Abstract: A measuring device including: a supply circuit for radiofrequency ignition including a transformer including a secondary winding connected to at least one resonator having a resonance frequency higher than 1 MHz, and including two electrodes capable of generating a spark upon an ignition control; a measuring capacitor connected in series between the secondary winding and the resonator; a measuring circuit of ionization current of the combustion gases in a cylinder of the internal combustion engine associated with the resonator, the circuit being connected at terminals of the measuring capacitor; and/or a measuring circuit that measures a voltage at the resonator terminals upon an ignition control, the circuit being connected to terminals of the measuring capacitor.

Abstract: A combustion state detecting apparatus for an internal combustion engine includes: an ignition plug (2) for generating a spark discharge for igniting an air-fuel mixture in a combustion chamber; an ignition coil (1) for supplying a high voltage to cause the ignition plug (2) to generate the spark discharge; and an ECU (3) for feeding a driving signal for driving the ignition coil (1). An electromotive force (secondary voltage) due to electromagnetic induction when a primary current is caused to flow through a primary winding of the ignition coil (1) in response to the driving signal from the ECU (3) is applied to the ignition plug (2) to detect an ion current generated in the combustion chamber to detect a combustion state in the ignition plug based thereon.

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: Disclosed is a way to detect ionization within a cylinder of an internal combustion engine where the engine selectively operates in either a spark ignition mode or a HCCI mode. A single ionization detector circuit adapts in response to a control input to alter its bias voltage and its gain to selectively enable effective detection of ionization for each of two different operational modes of an internal combustion engine.

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 internal-combustion-engine combustion condition detection apparatus that can accurately comprehend a combustion condition is obtained. The internal-combustion-engine combustion condition detection apparatus includes an ion-current detection device (41) that detects an ion current generated during combustion and ignition devices including a first ignition device (21) having a first ignition plug (11) that causes main combustion in a combustion chamber (33) and a second ignition device (22) having a second ignition plug (12) disposed in the same combustion chamber (33) as and spaced apart from the first ignition plug (11) of the first ignition device (21); the ion-current detection device (41) detects a combustion ion current that is generated in the second ignition device (22) regardless of whether or not ignition is performed by the second ignition device (22), thereby detecting pre-ignition or a precursor phenomenon of pre-ignition.

Abstract: In a circuit for and a method of detecting combustion-relevant variables in an internal combustion engine an ionization signal is determined in dependence on the flame. To improve the accuracy of detection the ionisation measurement circuit is connected to the ignition electrode and decoupled from the ignition coil by way of a decoupling means. In the method a voltage potential is built up in a measurement voltage storage unit in the ignition phase with an ignition current. During at least one measurement phase the voltage potential is applied by way of a measurement resistor to an ignition electrode, wherein the ignition voltage is decoupled from the measurement voltage storage unit or from the measurement resistor when the voltage falls below a threshold voltage.

Abstract: An internal-combustion-engine combustion condition detection apparatus that can accurately comprehend a combustion condition is obtained. The internal-combustion-engine combustion condition detection apparatus includes an ion-current detection device (41) that detects an ion current generated during combustion and ignition devices including a first ignition device (21) having a first ignition plug (11) that causes main combustion in a combustion chamber (33) and a second ignition device (22) having a second ignition plug (12) disposed in the same combustion chamber (33) as and spaced apart from the first ignition plug (11) of the first ignition device (21); the ion-current detection device (41) detects a combustion ion current that is generated in the second ignition device (22) regardless of whether or not ignition is performed by the second ignition device (22), thereby detecting pre-ignition or a precursor phenomenon of pre-ignition.

Abstract: The invention relates of a method for determining a combustion state of an internal combustion engine, for detecting an ion current generated within a combustion chamber of the internal combustion engine, including the steps of measuring a characteristic value of the ion current detected during a period that the ion current is generated and a generation period in which the ion current is generated, and determining a combustion state on the basis of a relation between the characteristic value and the generation period with respect to an elapsed time from an ignition, and the method comprises determining that the combustion state is normal, by setting a determination reference to be larger with respect to the characteristic value and shorter with respect to the generation period, in the case that the elapsed time from the ignition is short, and determining that the combustion is normal, by setting the determination reference to be smaller with respect to the characteristic value and longer with respect to the g

Abstract: According to the present invention, in a spark ignition-type internal combustion engine which has a spark plug and mounted in a vehicle, an ion current generated in a combustion chamber through the spark plug after ignition is detected and smoldering of the spark plug is determined on the basis of the detected ion current. An operation state of the internal combustion engine is detected and smoldering of the spark plug is determined based on that the detected ion current satisfies a predetermined condition when the detected operation state falls within an operation determination range set corresponding to an operation range in which an intake port pressure close to an atmospheric pressure is achieved using predetermined engine speed as an upper limit and a predetermined intake port pressure as a lower limit.