An ignition device for an internal combustion engine is provided which includes a spark plug and a controller. The spark plug has a housing with a head protruding into a combustion chamber of the engine. The head has at least a portion located downstream of a spark gap of the spark plug in an air-fuel mixture flow within the combustion chamber. The controller works to perform a plurality of discharge events in the spark plug in each cycle of an operation of the engine. This improves the ability of the spark plug to ignite the mixture without need to increase an ignition energy.

To provide an ignition apparatus which can turn on and off the sub primary coil according to extension degree of the discharge path of the spark discharge. An ignition apparatus is provided with an ignition coil that is provided with a main primary coil, a sub primary coil which generates energization magnetic flux of a direction opposite to the energization magnetic flux of the main primary coil, and a secondary coil which is magnetically coupled with the main primary coil and the sub primary coil and supplies spark discharge energy to a spark plug; and after turning off energization to the main primary coil, based on a detection value of terminal voltage of the main primary coil, turns on and off the sub switch circuit to turn on and off energization to the sub primary coil and additionally supply spark discharge energy to the secondary coil.

An ignition device for generating a spark discharge at a spark plug based on a first voltage from a first supply and a second voltage from a second supply. The second voltage is higher than the first voltage. In the ignition device, a primary coil includes a center tap, a first terminal on a ground side of the center tap, and a second terminal on a first-supply side of the center tap, and a secondary coil is electromagnetically coupled to the primary coil and electrically connected to the spark plug. A first switch is configured to make or break an electrical connection between the first terminal and ground, a second switch is configured to make or break an electrical connection between the second supply and the center tap, and a third switch is configured to pass or interrupt a current from the second terminal to the first supply. A controller is configured to control an on/off state of each of the first to third switches.

An ignition device for generating a spark discharge at a spark plug based on a first voltage from a first supply and a second voltage from a second supply. The second voltage is higher than the first voltage. In the ignition device, a primary coil includes a center tap, a first terminal on a ground side of the center tap, and a second terminal on a first-supply side of the center tap, and a secondary coil is electromagnetically coupled to the primary coil and electrically connected to the spark plug. A first switch is configured to make or break an electrical connection between the first terminal and ground, a second switch is configured to make or break an electrical connection between the second supply and the center tap, and a third switch is configured to pass or interrupt a current from the second terminal to the first supply. A controller is configured to control an on/off state of each of the first to third switches.

Premixed engines have ignition issues when engine speed and load are below a predetermined range. An ignition apparatus for igniting a premixed charge in a gaseous-fueled internal combustion engine comprises an ignition device associated with a combustion chamber of the internal combustion engine. There is at least one of a dilutant injector for introducing a diluting agent that forms a stratified charge around the ignition device and an enrichment injector for introducing gaseous fuel that forms a stratified charge around the ignition device. An electronic controller is operatively connected with the ignition device and the at least one of the dilutant injector and the enrichment injector and programed to at least one of actuate the dilutant injector to introduce the diluting agent when the ignition device decreases a local air-fuel equivalence ratio around the ignition device below a predetermined threshold; and actuate the enrichment injector to introduce the gaseous fuel to decrease the local air-fuel equivalence ratio when engine load and engine speed are below a predetermined threshold engine load and speed range and when the ignition device does not affect the local air-fuel equivalence around the ignition device.

An ignition coil includes a first winding, a second winding, and a third winding. A first switch is electrically connected to the first winding. A battery is electrically connected to the first winding. A booster is electrically connected to the battery. A second switch is electrically connected to the third winding. A drive device drives the first switch and the second switch. The drive device turns the first switch from on-state to off-state to allow a secondary current to flow through the second winding, turns the second switch from off-state to on-state to supply an output of the booster to the third winding, and superimpose a second current to the second winding. When a third winding current becomes equal to or greater than a predetermined value, the booster controls such that power generated by the third winding current and an output voltage of the booster is restricted to constant power.

An ignition coil includes a first winding, a second winding, and a third winding. A first switch is electrically connected to the first winding. A battery is electrically connected to the first winding. A booster is electrically connected to the battery. A second switch is electrically connected to the third winding. A drive device drives the first switch and the second switch. The drive device turns the first switch from on-state to off-state to allow a secondary current to flow through the second winding, turns the second switch from off-state to on-state to supply an output of the booster to the third winding, and superimpose a second current to the second winding. When a third winding current becomes equal to or greater than a predetermined value, the booster controls such that power generated by the third winding current and an output voltage of the booster is restricted to constant power.

An igniter assembly comprising an ignition coil assembly connected to a firing end assembly by an extension, with a valve assembly disposed in a pressure chamber of the extension, is provided. The valve assembly includes a valve stem biased toward the ignition coil assembly by a spring to seal the pressure chamber. The valve assembly is used to evacuate contents from the pressure chamber by pressing the valve stem toward the spring and allowing contents of the pressure chamber to travel through and past the valve stem and out of the pressure chamber. The valve assembly is also used to fill the pressure chamber with an insulating medium by pressing the valve stem toward the spring and allowing the insulating medium to travel through and past the valve stem and into the pressure chamber after evacuating the contents out of the pressure chamber.

An ignition device ignites a mixture of air and fuel gas by plasma to generate an initial flame. The ignition device includes a spark plug having an inner conductor, a cylindrical outer conductor that holds the inner conductor inside, and a dielectric provided between the inner conductor and the outer conductor, and the spark plug configured to emit an electromagnetic wave to a plasma formation space between the inner conductor and the outer conductor to generate a plasma. The ignition device includes an electromagnetic wave power supply that generates the electromagnetic wave by inputting the electromagnetic wave power Ps to the spark plug and a power supply control unit that controls the electromagnetic wave power supply. The electromagnetic wave power supply is configured to generate high frequency power at a number of different frequencies. The power supply control unit outputs at least one of the plurality of high frequency powers generated by the electromagnetic wave power supply as the electromagnetic wave power.

In order to provide a power conversion device capable of estimating a load voltage with high accuracy without directly detecting the load voltage to be applied to a load, a control circuit is provided, which includes a means for estimating the load voltage to be applied to the load based on an electric current of a resonant circuit, an AC frequency of an inverter and an electrostatic capacitance of the load, or a means for estimating the load voltage based on the electric current of the resonant circuit, the AC frequency of the inverter, an inductance of a resonant coil and a correction coefficient previously set from a relationship between a voltage of the resonant coil and the load voltage, and which controls an output to a target load voltage based on the estimated load voltage.