An electronic ignition system for an internal combustion engine comprises an ignition coil (2) provided with at least a primary winding (3) and a secondary winding (4), a switch (6) connected to the primary winding (3) and drivable in an open and/or closed position according to the value of a driving signal, a control unit (7) associated to the switch (6) and configured to drive it in open and/or closed position according to the value of the driving signal (G). Such system also comprises a voltage changing electronic element (8) connected to the electrical connection (5), operatively interposed between the electrical connection (5) and the primary winding (3), and configured to change the voltage value of the primary winding (3) according to the value of a control signal between at least a first (V1) and a second (V2) voltage value. The system also comprises a ionization measuring device (20) around said discharge gap (100a) of the spark plug (100) associated with the secondary winding (4) and arranged to detect a current value in the secondary winding (4) and to send a signal representative of said value to the control unit (7), wherein the control unit (7) is configured to activate said measuring device (20) upon the shutdown of the electric arc or spark.

A combustion speed, for example, is estimated or evaluated, with a required accuracy, more simply than the conventional art, while reducing man-hours to produce a heat generation rate waveform of an internal combustion engine. An increase rate of a heat generation rate relative to a change in a crank angle in a heat generation rate increasing period (e.g., a first-half combustion period a) in which the heat generation rate increases after ignition of an air-fuel mixture is defined as a heat generation rate gradient b/a that is one of characteristic values of the heat generation rate waveform. The heat generation rate gradient is estimated based on a fuel density (e.g., fuel density .sub.fuel@dQpeak at heat generation rate maximum time) at a predetermined time set in advance in the heat generation rate increasing period so as to produce the heat generation rate waveform using the estimated heat generation rate gradient.

A dual ignition system for aircraft that includes a left and right ignition element, each having a primary module and a secondary module, both operational. A switch mechanism activated by a cockpit control panel selects either the primary mode or the secondary mode for each ignition element. The primary modules could be variable mode modules and the secondary modules could be fixed mode modules. Each module includes a sense magnet responsive to a drive shaft to detect engine position. Each fixed module has a sensor cluster activated by the sense magnet and each variable module has a position encoder activated by the sense magnet.

A dual ignition system for aircraft that includes a left and right ignition element, each having a primary module and a secondary module, both operational. A switch mechanism activated by a cockpit control panel selects either the primary mode or the secondary mode for each ignition element. The primary modules could be variable mode modules and the secondary modules could be fixed mode modules. Each module includes a sense magnet responsive to a drive shaft to detect engine position. Each fixed module has a sensor cluster activated by the sense magnet and each variable module has a position encoder activated by the sense magnet.

An ignition control system for an internal combustion engine has a coil connector for connecting to an ignition coil, a processor coupled to the coil connector, and a memory coupled to the processor. The memory contains instructions for the processor to, in communication with the ignition coil, achieve and maintain a target spark duration by dynamically controlling a coil dwell set-point of the ignition coil. The processor energizes the ignition coil during a first ignition sequence based on the coil dwell set-point, directly measure spark duration of the first ignition sequence by monitoring a voltage reflection on a primary side of the ignition coil, adjust the coil dwell set-point for a second ignition sequence based on the target spark duration and the measured spark duration, and energizes the ignition coil during the second ignition sequence based on the adjusted coil dwell set-point.

An ignition control system for an internal combustion engine has a coil connector for connecting to an ignition coil, a processor coupled to the coil connector, and a memory coupled to the processor. The memory contains instructions for the processor to, in communication with the ignition coil, achieve and maintain a target spark duration by dynamically controlling a coil dwell set-point of the ignition coil. The processor energizes the ignition coil during a first ignition sequence based on the coil dwell set-point, directly measure spark duration of the first ignition sequence by monitoring a voltage reflection on a primary side of the ignition coil, adjust the coil dwell set-point for a second ignition sequence based on the target spark duration and the measured spark duration, and energizes the ignition coil during the second ignition sequence based on the adjusted coil dwell set-point.

An induction cleaning analyzing system includes a pressure sensor, an ignition event detector, and a control module. The pressure sensor measures airflow pressures of intake air and/or exhaust from cylinders in a common airflow pathway of a vehicle. The ignition event detector determines ignition events of the cylinders. The control module obtains pressure waveforms representative of the airflow pressures and divides the pressure waveforms into waveform segments. The control module associates different subsets of the waveform segments with different ones of the cylinders using the ignition events. The control module also identifies cyclic variations in the airflow pressures flowing in the common airflow pathway and caused by at least one of the cylinders by examining the waveform segments associated with the at least one of the cylinders.

An induction cleaning analyzing system includes a pressure sensor, an ignition event detector, and a control module. The pressure sensor measures airflow pressures of intake air and/or exhaust from cylinders in a common airflow pathway of a vehicle. The ignition event detector determines ignition events of the cylinders. The control module obtains pressure waveforms representative of the airflow pressures and divides the pressure waveforms into waveform segments. The control module associates different subsets of the waveform segments with different ones of the cylinders using the ignition events. The control module also identifies cyclic variations in the airflow pressures flowing in the common airflow pathway and caused by at least one of the cylinders by examining the waveform segments associated with the at least one of the cylinders.

An ignition device and strategies are provided for extending spark plug life and air-fuel mixture lean limits in natural gas engines while maintaining or improving the engine thermal efficiency. The ignition device may include a plug body extending between a terminal end and an electrode end, a plurality of electrode pairs radially disposed on the electrode end each having an inner electrode and an outer electrode and an insulating body electrically isolating each of the electrode pairs from one another and each of the inner electrodes from the outer electrodes.

An ignition apparatus includes an ignition plug, a boost transformer, an ignition power source and a measurement unit. The ignition plug has a center electrode and a ground electrode. The boost transformer supplies the ignition plug with electric power generated in a secondary coil upon supply of AC power from the ignition power source to a primary coil. The measurement unit measures the discharge voltage of the ignition plug. The ignition power source includes a discharge state determining unit that determines the discharge state of the ignition plug based on the measured discharge voltage and a current controlling unit that controls electric current supplied to the primary coil. When a discharge path formed between the center and ground electrodes of the ignition plug is determined by the discharge state determining unit as being in an over-extended state, the current controlling unit reduces the electric current supplied to the primary coil.