In an ignition device having an ignition plug for igniting a fuel mixture gas introduced in a combustion chamber, a super hydrophilic membrane is formed on a surface at the combustion chamber side of a plug forming member of the ignition plug. The super hydrophilic membrane contains super hydrophilic particles and thermal excitation catalyst particles, and satisfies a relationship of θ.sub.W2<θ.sub.W1, where θ.sub.W1 indicates a water contact angle between water and the plug forming member on which no super hydrophilic membrane is formed, and θ.sub.W2 indicates a water contact angle between water and the plug forming member on which the super hydrophilic membrane is formed.

In an ignition device having an ignition plug for igniting a fuel mixture gas introduced in a combustion chamber, a super hydrophilic membrane is formed on a surface at the combustion chamber side of a plug forming member of the ignition plug. The super hydrophilic membrane contains super hydrophilic particles and thermal excitation catalyst particles, and satisfies a relationship of θ.sub.W2<θ.sub.W1, where θ.sub.W1 indicates a water contact angle between water and the plug forming member on which no super hydrophilic membrane is formed, and θ.sub.W2 indicates a water contact angle between water and the plug forming member on which the super hydrophilic membrane is formed.

An ignition device for an internal combustion engine includes optical focusing lenses, including a center optical focusing lens and satellite optical focusing lens. The center optical focusing lens focuses laser light from a laser generator to a center ignition point in a combustion chamber of a cylinder of the internal combustion engine. The satellite optical focusing lenses focus laser light from the laser generator to satellite ignition points in the combustion chamber of the cylinder of the internal combustion engine. The satellite optical focusing lenses are directionally angled away from the center optical focusing lens. A firing depth of the center ignition point is greater than a firing depth of the at least one satellite ignition point.

An ignition device for an internal combustion engine includes optical focusing lenses, including a center optical focusing lens and satellite optical focusing lens. The center optical focusing lens focuses laser light from a laser generator to a center ignition point in a combustion chamber of a cylinder of the internal combustion engine. The satellite optical focusing lenses focus laser light from the laser generator to satellite ignition points in the combustion chamber of the cylinder of the internal combustion engine. The satellite optical focusing lenses are directionally angled away from the center optical focusing lens. A firing depth of the center ignition point is greater than a firing depth of the at least one satellite ignition point.

An internal combustion engine with a piston having a piston head with a resonance cavity opening onto the head, and where a fuel nozzle located in a cylinder head is positioned to inject a fuel such as natural gas into the combustion chamber where resonance formed within the resonance cavity will ignite the fuel without the need of a spark plug. Inlet and exhaust ports in the cylinder head allow for air and combustion gas enter or leave the combustion chamber.

An ignition system (10) comprises a high voltage transformer (12) comprising a primary winding (12.1) and a secondary winding (12.2). A primary resonant circuit (26) is formed by the primary winding (12.1) and a primary circuit capacitance (24). A secondary resonant circuit (16) is formed by an ignition plug (14), as a load, the secondary winding (12.2); the ignition plug (14) being represented by a secondary circuit capacitance (18) and a secondary circuit load resistance (Rp) put in parallel. Said load resistance value varies during an ignition cycle. The primary resonant circuit (26) and the secondary resonant circuit (16) have a common mode resonance frequency (f.sub.c) and a differential mode resonance frequency (f.sub.d). A controller (28) is configured to cause a drive circuit (22) to drive the primary winding at a frequency, which is either the common-mode resonance frequency (f.sub.c) or the differential mode resonance frequency (f.sub.d) and is connected to a feed-back circuit (50) to adapt the frequency of the primary winding to the variable load resistance.

An ignition unit improves an air-fuel-ratio, i.e., good mileage and lean burn without changing a gasoline engine structure significantly. The ignition unit comprises a discharge device including a booster and a discharger provided at an output side of the booster, the booster having a resonance structure configured to boost the electromagnetic wave inputted from the electromagnetic wave oscillator so as to cause a discharge from the discharger, and an electromagnetic wave emitter electrically connected to the electromagnetic wave oscillator and configured to emit the electromagnetic wave inputted from the electromagnetic wave oscillator. Moreover, the ignition unit further includes a housing part including a first hole into which the discharge device is inserted and a second hole into which the electromagnetic wave emitter is inserted such that the housing part houses therein both the discharge device and the electromagnetic wave emitter, and the housing part can be inserted into a single hole of a cylinder head of an internal combustion engine.

A compression-ignition type internal combustion engine that burns a gaseous fuel, improves an ignition performance not only at a center part of the combustion chamber but also at an outer edge part. The compression-ignition engine comprises an electromagnetic wave generator configured to generate an electromagnetic wave, a controller configured to control the electromagnetic wave generator, and a plasma generator comprising a boosting circuit that constitutes a resonator configured to boost the electromagnetic wave, a first electrode configured to receive an output from the boosting circuit, and a second electrode provided to a vicinity of the first electrode, and the plasma generator is configured such that the first electrode is extruded and exposed toward a combustion chamber of the internal combustion engine, and a plurality of plasma generators are provided.

A compression-ignition type internal combustion engine that burns a gaseous fuel, improves an ignition performance not only at a center part of the combustion chamber but also at an outer edge part. The compression-ignition engine comprises an electromagnetic wave generator configured to generate an electromagnetic wave, a controller configured to control the electromagnetic wave generator, and a plasma generator comprising a boosting circuit that constitutes a resonator configured to boost the electromagnetic wave, a first electrode configured to receive an output from the boosting circuit, and a second electrode provided to a vicinity of the first electrode, and the plasma generator is configured such that the first electrode is extruded and exposed toward a combustion chamber of the internal combustion engine, and a plurality of plasma generators are provided.

A method for controlling a corona ignition system in which a corona discharge is produced at an ignition electrode by exciting a resonating circuit with an AC voltage produced by a high-frequency generator. The AC voltage is adjusted to a target value depending on an operating state of the engine. Combustion onset is determined by evaluating an electrical variable of the resonating circuit and the target value of the AC voltage is reduced by a predefined value following a predefined number of engine cycles or a predefined operating period. The determined combustion onset is evaluated in one or more engine cycles. The target value for the momentary engine operating state is then increased if, by evaluation of the combustion onset, it is found that a predefined requirement is no longer met. Otherwise, the reduced target value is stored as a new target value for the momentary engine operating state.