An ignition device includes a spark plug, a measurement value detector, an electrical breakdown determiner, an AC voltage applying section, and a first changing section. The measurement value detector includes primary and secondary coils, and detects at least one measurement value among an ignition coil, a primary current, a primary voltage, a secondary current, and a secondary voltage. The electrical breakdown determiner determines whether a discharge has become an electrical breakdown state based on the measurement value. The AC voltage applying section applies an AC voltage of a first predetermined frequency that causes voltage resonance to the primary coil. The first changing section changes the frequency of the AC voltage to a second predetermined frequency that can maintain the electrical breakdown state and is lower in frequency than the first predetermined frequency when it is determined that the discharge has become the electrical breakdown state.

Disclosed is a piston ported two-stroke compression ignition internal combustion engine comprising: a cylinder having a fixed closed end, and a piston for reciprocation within the cylinder, wherein the closed end of the cylinder and the piston together define a combustion chamber therebetween; at least one heater to heat the combustion chamber; and a controller to control the heater to heat the combustion chamber when the controller determines that a temperature of the combustion chamber has fallen below a threshold temperature during reciprocation of the piston within the cylinder.

A piston is arranged to move in a cylinder to define a variable volume chamber, and can expand in two directions under the influence of pressure in the variable volume chamber to provide sealing against the cylinder. The piston can comprise a primary foot and a secondary foot arranged to move relative to each other in a first direction. The primary foot and the secondary foot can each comprise plural segments arranged to move relative to each other in a second direction. The piston may be suitable for use in an inner rotor, where it forms the end of a projection of the inner rotor and fully exits and reenters the cylinders.

An internal combustion engine including an igniter disposed at least partially within an aperture defined in a housing of the engine, the igniter having a body including a tip supporting portion and having a tip extending from the tip supporting portion. A cooling sleeve is disposed around the tip supporting portion, and the cooling sleeve defines a path of heat transfer between the tip supporting portion and the housing. The engine may be a rotary engine. A method for cooling an igniter of an internal combustion engine is also discussed.

Disclosed is a piston ported two-stroke compression ignition internal combustion engine comprising: a cylinder having a fixed closed end, and a piston for reciprocation within the cylinder, wherein the closed end of the cylinder and the piston together define a combustion chamber therebetween; at least one heater to heat the combustion chamber; and a controller to control the heater to heat the combustion chamber when the controller determines that a temperature of the combustion chamber has fallen below a threshold temperature during reciprocation of the piston within the cylinder.

An internal combustion engine including an igniter disposed at least partially within an aperture defined in a housing of the engine, the igniter having a body including a tip supporting portion and having a tip extending from the tip supporting portion. A cooling sleeve is disposed around the tip supporting portion, and the cooling sleeve defines a path of heat transfer between the tip supporting portion and the housing. The engine may be a rotary engine. A method for cooling an igniter of an internal combustion engine is also discussed.

A rotating piston internal combustion engine including a housing which includes a housing wall that forms an operating chamber, and in which housing a rotatable rotating piston is arranged which extends through the operating chamber and moves edges of the rotating piston along the housing wall that forms a running surface, wherein a portion of the operating chamber functions as a combustion chamber together with an associated combustion chamber wall for igniting a fuel that is arranged in the operating chamber, characterized in that at least one microwave window is arranged in the combustion chamber wall, wherein a device for injecting microwave energy in a form of microwaves into the combustion chamber of the operating chamber is arranged at a side of the microwave window that is oriented away from the combustion chamber.

An ignition device includes a spark plug, a measurement value detector, an electrical breakdown determiner, an AC voltage applying section, and a first changing section. The measurement value detector includes primary and secondary coils, and detects at least one measurement value among an ignition coil, a primary current, a primary voltage, a secondary current, and a secondary voltage. The electrical breakdown determiner determines whether a discharge has become an electrical breakdown state based on the measurement value. The AC voltage applying section applies an AC voltage of a first predetermined frequency that causes voltage resonance to the primary coil. The first changing section changes the frequency of the AC voltage to a second predetermined frequency that can maintain the electrical breakdown state and is lower in frequency than the first predetermined frequency when it is determined that the discharge has become the electrical breakdown state.

The internal combustion engine has an internal combustion engine main body and a substantially columnar ignition coil. A head part at one end of the ignition coil is provided with an electromagnetic wave element for outputting electromagnetic waves irradiated into a combustion chamber of the internal combustion engine main body, and a plurality of supporting components are provided for supporting the ignition coil when an attaching part at the other end of the ignition coil is attached to a spark plug, the supporting components supporting the ignition coil either at or near a nodal point in a characteristic vibration mode of vibration occurring in the ignition coil along with vibration of the internal combustion engine main body. The ignition coil is not supported on the side toward the head part relative to the support member nearest the head part.

Disclosed is a piston ported two-stroke compression ignition internal combustion engine comprising: a cylinder having a fixed closed end, and a piston for reciprocation within the cylinder, wherein the closed end of the cylinder and the piston together define a combustion chamber therebetween; at least one heater to heat the combustion chamber; and a controller to control the heater to heat the combustion chamber when the controller determines that a temperature of the combustion chamber has fallen below a threshold temperature during reciprocation of the piston within the cylinder.