A booster circuit for use with an ignition system for an internal combustion engine is provided. The booster circuit includes a relay control circuitry disposed in parallel between the voltage source and the one or more ignition coils for igniting fuel in the engine in synchronism with engine operation; a controllable switching element for selectively completing a booster circuit for connecting the relay control circuitry in series with the voltage source and the one or more ignition coils; and the booster circuit having electronic circuitry including at least one output for providing booster energy at the at least one output, when the booster circuit is completed by the controllable switching element to assure producing of a suitable voltage applied to the one or more ignition coils.

An apparatus for igniting a combustible mixture. In one example, the apparatus can include a coaxial cavity resonator assembly in a combustion environment. The apparatus can also include an operational feedback system and a controller. The operational feedback system can measure at least one of a voltage value and a current value of the coaxial cavity resonator assembly in the combustion environment. The controller can be configured to determine a condition of the coaxial cavity resonator assembly and modulate operation of the coaxial cavity resonator assembly based at least in part on the determined condition.

An apparatus for igniting a combustible mixture. In one example, the apparatus can include a coaxial cavity resonator assembly in a combustion environment. The apparatus can also include an operational feedback system and a controller. The operational feedback system can measure at least one of a voltage value and a current value of the coaxial cavity resonator assembly in the combustion environment. The controller can be configured to determine a condition of the coaxial cavity resonator assembly and modulate operation of the coaxial cavity resonator assembly based at least in part on the determined condition.

An ignition apparatus is provided which ignites a mixture of air and fuel gas by plasma to generate an initial flame. The apparatus includes: a spark plug that includes an inner conductor, a cylindrical outer conductor that holds the inner conductor thereinside, and a dielectric that is provided between the inner conductor and the outer conductor, and that generates plasma in a plasma formation space between the inner conductor and the outer conductor; an electromagnetic wave power supply that generates an electromagnetic wave to apply electromagnetic wave power to the spark plug; an evaluation section that evaluates a state of formation of the plasma; a determination section that determines a matching object of the electromagnetic wave based on an evaluation result by the evaluation section; and a coupled state control section that controls a matching condition of the electromagnetic wave so that the electromagnetic wave matches the matching object.

An ignition apparatus is provided which ignites a mixture of air and fuel gas by plasma to generate an initial flame. The apparatus includes: a spark plug that includes an inner conductor, a cylindrical outer conductor that holds the inner conductor thereinside, and a dielectric that is provided between the inner conductor and the outer conductor, and that generates plasma in a plasma formation space between the inner conductor and the outer conductor; an electromagnetic wave power supply that generates an electromagnetic wave to apply electromagnetic wave power to the spark plug; an evaluation section that evaluates a state of formation of the plasma; a determination section that determines a matching object of the electromagnetic wave based on an evaluation result by the evaluation section; and a coupled state control section that controls a matching condition of the electromagnetic wave so that the electromagnetic wave matches the matching object.

A corona comprises a central electrode surrounded by an insulator, which is surrounded by a conductive component. The conductive component includes a shell and an intermediate part both formed of an electrically conductive material. The intermediate part is a layer of metal which brazes the insulator to the shell. An outer surface of the insulator presents a lower ledge, and the layer of metal can be applied to the insulator above the lower ledge prior to or after inserting the insulator into the shell. The conductive inner diameter is less than an insulator outer diameter directly below the lower ledge such the insulator thickness increases toward the electrode firing end. The insulator outer diameter is also typically less than the shell inner diameter so that the corona igniter can be forward-assembled.

A corona comprises a central electrode surrounded by an insulator, which is surrounded by a conductive component. The conductive component includes a shell and an intermediate part both formed of an electrically conductive material. The intermediate part is a layer of metal which brazes the insulator to the shell. An outer surface of the insulator presents a lower ledge, and the layer of metal can be applied to the insulator above the lower ledge prior to or after inserting the insulator into the shell. The conductive inner diameter is less than an insulator outer diameter directly below the lower ledge such the insulator thickness increases toward the electrode firing end. The insulator outer diameter is also typically less than the shell inner diameter so that the corona igniter can be forward-assembled.

A barrier-discharge-type ignition apparatus that can accurately determine the application voltage, of a barrier ignition plug, that causes a non-ignition discharge to occur. In the barrier-discharge-type ignition apparatus, in a combustion assist control, the voltage difference between the one-period-prior application voltage and the present-period application voltage in the AC period is calculated based on an application voltage detected by a voltage detection circuit; then, it is determined whether or not a discharge exists in the barrier ignition plug, based on the comparison between the voltage difference and a preliminarily set discharge determination threshold value.

A barrier-discharge-type ignition apparatus that can accurately determine the application voltage, of a barrier ignition plug, that causes a non-ignition discharge to occur. In the barrier-discharge-type ignition apparatus, in a combustion assist control, the voltage difference between the one-period-prior application voltage and the present-period application voltage in the AC period is calculated based on an application voltage detected by a voltage detection circuit; then, it is determined whether or not a discharge exists in the barrier ignition plug, based on the comparison between the voltage difference and a preliminarily set discharge determination threshold value.

Methods and systems are provided for an engine having a pre-chamber ignition system. In one example, a method may include adjusting a valve coupled between a pre-chamber of an engine cylinder and a main chamber of the engine cylinder between a fully open position and a fully closed position based on whether pre-chamber ignition is desired or direct spark ignition is desired. In this way, the engine may be operated with direct spark ignition during conditions when pre-chamber combustion has reduced stability without including additional spark plugs and air injectors.