An internal combustion engine, a method of operating the internal combustion engine, and a controller are disclosed. The method may be implemented in part by the controller and comprises determining a shaft angle of an engine shaft; supplying, to an ion sensor fluidly coupled to a combustion chamber of the engine a low voltage at a beginning of a combustion cycle to generate an ion sensor current and a high voltage during an ionization voltage window based at least in part on the shaft angle, wherein the low voltage is configured to prevent premature ignition of fuel in the combustion chamber and the high voltage exceeds the low voltage and is configured to increase the ion sensor current above a current threshold.

Knocking and pre-ignition are identified, without contributing to pre-ignition, even when vibration magnitudes and timings of occurrence of the knocking and pre-ignition are the same. When detecting an abnormal combustion that cannot be identified as a knocking or pre-ignition, ignition timing is advanced, at which time knocking is identified when an abnormal combustion intensity increases, and pre-ignition is identified when a difference between ignition timing and abnormal combustion occurrence timing increases.

Knocking and pre-ignition are identified, without contributing to pre-ignition, even when vibration magnitudes and timings of occurrence of the knocking and pre-ignition are the same. When detecting an abnormal combustion that cannot be identified as a knocking or pre-ignition, ignition timing is advanced, at which time knocking is identified when an abnormal combustion intensity increases, and pre-ignition is identified when a difference between ignition timing and abnormal combustion occurrence timing increases.

The subject matter of this specification can be embodied in, among other things, a method that includes receiving a collection of measurements of electric current amplitude in a primary winding of an engine ignition system having the primary winding and a spark plug, identifying an ignition start time, identifying an inflection point based on the plurality of measurements, determining an inflection point time representative of a time at which the identified inflection point occurred, determining a spark start time based on an amount of time between the ignition start time and the inflection point time, and providing a signal indicative of the spark start time.

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 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 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.

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.