A fuel combustion apparatus 2 according to the present invention includes: a combustion cylinder 4; a fuel feed unit 6 that introduces a swirling flow of an air-fuel mixture into the combustion cylinder; an ignition unit 10 including an igniter 32 located in the combustion cylinder 4; an ion detection unit 12 including a detector 40 located in the combustion cylinder 4; and a control unit 14 that adjusts a mixing ratio of the fuel based on a detection result obtained by the ion detection unit 12. Preferably, the fuel is ammonia. Preferably, the detector 40 is located in the vicinity of the igniter 32.

An electronic device for controlling an ignition coil of an internal combustion engine includes a high voltage switch, a driving unit and a control unit. The driving unit controls the closure of the switch during charging energy in the primary winding and the opening of the switch during transferring energy from the primary winding to a secondary winding. A current measuring circuit is connected in series to a second terminal of the secondary winding to detect current generated on the secondary winding during the charging step and generate a signal representative of the detected current. The control unit receives the signal representative of the current detected by the measuring circuit, compares a relevant value of such signal with a predefined first reference value and activates a mode for detecting a soiling of the spark plug when the relevant value of the signal exceeds said predefined first reference value.

Energization abnormality of a switch element of an internal combustion engine ignition device is detected appropriately. To this end, in an internal combustion engine ignition device that includes an ignition coil and an ignition plug, the ignition coil includes a primary coil including a main primary coil and a sub primary coil and a secondary coil that generates secondary current in response to a voltage variation generated in the primary coil. The internal combustion engine ignition device includes a main switch element that performs energization/deenergization of the main primary coil in a first direction, a sub primary coil magnetic flux generation state switching unit capable of switching between a forward direction magnetic flux generation state in which energization of the sub primary coil in the first direction is performed and an opposite direction magnetic flux generation state in which energization of the sub primary coil in a second direction is performed, and an abnormality detection section that detects energization abnormality to the sub primary coil. The abnormality detection section is configured so as to detect energization abnormality on the basis of overlap between energization in the first direction and energization in the second direction of the sub primary coil.

The invention relates to a method for operating an internal combustion engine with fuel which is combusted using a spark plug. According to the invention, the aging of the spark plug, in particular the aging of an electric resistor of the spark plug, is monitored during the operation of the internal combustion engine, wherein electromagnetic radiation of the spark plug is detected for monitoring purposes. The invention additionally relates to a controller for carrying out the method.

A fuel combustion apparatus 2 according to the present invention includes: a combustion cylinder 4; a fuel feed unit 6 that introduces a swirling flow of an air-fuel mixture into the combustion cylinder; an ignition unit 10 including an igniter 32 located in the combustion cylinder 4; an ion detection unit 12 including a detector 40 located in the combustion cylinder 4; and a control unit 14 that adjusts a mixing ratio of the fuel based on a detection result obtained by the ion detection unit 12. Preferably, the fuel is ammonia. Preferably, the detector 40 is located in the vicinity of the igniter 32.

Ignitability of a fuel by a spark plug is improved while an increase in the number of ignition coils is suppressed. A control device for an internal combustion engine includes an ignition control unit 83 which controls energization of an ignition coil 300a and an ignition coil 300b which each provide electric energy to a spark plug which discharges in a cylinder of an internal combustion engine to ignite a fuel, and a discharge amount detection unit which detects an inter-electrode voltage of the spark plug. After the ignition control unit 83 discharges the spark plug using the electric energy of the ignition coil 300a, the ignition control unit estimates a voltage which is supply-able from the ignition coil 300a to the spark plug, and controls energization of the ignition coil so as to supply the electric energy of the second ignition coil 300b to the spark plug when a difference d between the estimated supply-able voltage and a required voltage based on the voltage detected by the discharge amount detection unit is equal to or less than a predetermined threshold value.

The invention relates to a method for operating an internal combustion engine with fuel which is combusted using a spark plug. According to the invention, the aging of the spark plug, in particular the aging of an electric resistor of the spark plug, is monitored during the operation of the internal combustion engine, wherein electromagnetic radiation of the spark plug is detected for monitoring purposes. The invention additionally relates to a controller for carrying out the method.

A method of detecting the breakdown voltage between the electrodes of a spark plug connected to an ignition coil for a cylinder ignition system, in an internal combustion engine, comprises a detection of an opening of the switch (105) on the primary winding (102) and a detection of a voltage on that primary winding (102), with the generation of a first signal (V.sub.1) representative of the voltage trend following the opening of the switch (105).

The first signal (V.sub.1) is then integrated and, following an identification of a breakdown at the ends of the spark plug (106), a breakdown voltage value is determined as a function of the value of the integrated signal at the time of the breakdown.

Ignitability of a fuel by a spark plug is improved while an increase in the number of ignition coils is suppressed. A control device for an internal combustion engine includes an ignition control unit 83 which controls energization of an ignition coil 300a and an ignition coil 300b which each provide electric energy to a spark plug which discharges in a cylinder of an internal combustion engine to ignite a fuel, and a discharge amount detection unit which detects an inter-electrode voltage of the spark plug. After the ignition control unit 83 discharges the spark plug using the electric energy of the ignition coil 300a, the ignition control unit estimates a voltage which is supply-able from the ignition coil 300a to the spark plug, and controls energization of the ignition coil so as to supply the electric energy of the second ignition coil 300b to the spark plug when a difference d between the estimated supply-able voltage and a required voltage based on the voltage detected by the discharge amount detection unit is equal to or less than a predetermined threshold value.

An ignition device for an internal combustion engine includes an ignition coil, a first switch, a secondary current adjuster, and controller. The ignition coil includes a primary coil, a core, and a secondary coil. The first switch switches an energized state of the primary coil between an ON state and an OFF state. The secondary current adjuster adjusts a current value of a secondary current flowing through the secondary coil. The controller controls the secondary current adjuster so that a current value of the secondary current in at least a part of a charging period of the ignition plug, which is a period from when the energized state of the primary coil is switched from the ON state to the OFF state by the first switch to when dielectric breakdown occurs in the ignition plug, becomes smaller than a peak value of the secondary current after the dielectric breakdown occurs.