A spark plug insulator comprising a ceramic body with a photopolymerized and sintered microstructure. The spark plug insulator can have one or more complex geometries, such as dual axial bores, channels or grooves for wiring or the like, or internal wells. In one embodiment, an internal well is situated in the nose portion of the axial bore. The internal well has a terminal end, a base, and a ceramic bounding ring that is diametrically reduced with respect to a diameter at the base of the internal well. In some embodiments, there is a center electrode shield portion adjacent the internal well, where a diameter of the center electrode shield portion is diametrically reduced with respect to the diameter at the base of the internal well.

The present invention relates to a spark plug extension body connecting an ignition coil with a spark plug for a spark ignited internal combustion engine, as well as a method for providing such a spark plug extension body for reduction of partial electrical discharges in the spark plug extension body. In conventional spark plug extensions are coil springs used as electrical conductor against the spark plug terminal and/or ignition coil terminal. These coil springs cause Corona effects and short circuiting requiring replacement of the spark plug extension. With the invention the entire electrical conductor (CR.sub.u, 64, CR.sub.L) is in a rod like form and at least both ends (CR.sub.u, CR.sub.L) of the electrical conductor (CR.sub.u, 64, CR.sub.L) are made as a monolith in a flexible and electrically conducting polymeric material, preferably electrically conducting rubber.

The present invention relates to a spark plug extension body connecting an ignition coil with a spark plug for a spark ignited internal combustion engine, as well as a method for providing such a spark plug extension body for reduction of partial electrical discharges in the spark plug extension body. In conventional spark plug extensions are coil springs used as electrical conductor against the spark plug terminal and/or ignition coil terminal. These coil springs cause Corona effects and short circuiting requiring replacement of the spark plug extension. With the invention the entire electrical conductor (CR.sub.u, 64, CR.sub.L) is in a rod like form and at least both ends (CR.sub.u, CR.sub.L) of the electrical conductor (CR.sub.u, 64, CR.sub.L) are made as a monolith in a flexible and electrically conducting polymeric material, preferably electrically conducting rubber.

In the spark plug heat rating measurement method and system based on spark discharge current active heating, the spark plug is installed in a constant-temperature water jacket cooling chamber with a specific torque. A constant spark discharge current control module is connected to the high-voltage terminal of the spark plug, to provide real-time controlled discharge current to heat up the high-voltage central electrode of the spark plug. During the spark discharge process, the temperature change of the high-voltage central electrode and the surrounding ceramic insulator are measured by a temperature detection module and used to determine the heat rating of the spark plug. By real time adjusting the discharge current level of the spark plug, or providing a same amount of spark energy to the spark gap, the heat ratings of spark plugs with different ceramic insulation structures can be evaluated through the temperature changes during discharge or after discharge.

The invention relates to a semiconductor body revolving around a main axis (A) for a spark plug of a turbine engine, the semiconductor body comprising a baseplate and an upper portion extending from the baseplate along the main axis, the baseplate comprising a bottom surface substantially defined in a plane perpendicular to the main axis and a first conical surface intended to cooperate by form-fitting at least partially with a contact surface of an outer electrode of the spark plug. According to the invention, the upper portion comprises an interface located opposite the bottom surface along the main axis (A) and featuring a profile that is at least partially corrugated.

A spark plug according to one embodiment of the present invention includes an insulator formed of an alumina-based sintered body, wherein the insulator contains 90 wt % or more of an aluminum component in terms of oxide, and wherein crystal grains of the insulator has an average grain size of 1.5 mm or smaller and a grain size standard deviation of 1.2 μm or smaller.

A spark plug according to one embodiment of the present invention includes an insulator formed of an alumina-based sintered body, wherein the insulator contains 90 wt % or more of an aluminum component in terms of oxide, and wherein crystal grains of the insulator has an average grain size of 1.5 mm or smaller and a grain size standard deviation of 1.2 μm or smaller.

An apparatus for igniting a fuel mixture provides an ignition system for generating a high-voltage ignition voltage, a circuit device comprising a circuit for superimposing a high-frequency signal on to the high-voltage ignition voltage, a spark plug in an engine block, and a transmission element having a high-voltage conductor which is guided in an insulation element. The high-voltage conductor is used for transmitting the ignition voltage, onto which the high-frequency signal has been superimposed, to the spark plug. Further provided is an electrically conducting shielding element which surrounds the high-voltage conductor in an electromagnetically shielding manner at least along one portion of the longitudinal axis of the high-voltage conductor. The shielding element is connected in an electrically conducting manner to a ground potential of the circuit device and establishes a connection between the ground potential of the circuit device and a ground electrode of the spark plug.

An apparatus for igniting a fuel mixture provides an ignition system for generating a high-voltage ignition voltage, a circuit device comprising a circuit for superimposing a high-frequency signal on to the high-voltage ignition voltage, a spark plug in an engine block, and a transmission element having a high-voltage conductor which is guided in an insulation element. The high-voltage conductor is used for transmitting the ignition voltage, onto which the high-frequency signal has been superimposed, to the spark plug. Further provided is an electrically conducting shielding element which surrounds the high-voltage conductor in an electromagnetically shielding manner at least along one portion of the longitudinal axis of the high-voltage conductor. The shielding element is connected in an electrically conducting manner to a ground potential of the circuit device and establishes a connection between the ground potential of the circuit device and a ground electrode of the spark plug.

A spark plug combustion ionization sensor for measuring ion current inside the cylinder of an internal combustion engine. The sensor measures ion current which flows when the energy released during combustion ionizes the air inside the cylinder, and thus can detect combustion and emission parameters. The spark plug combustion ionization sensor generally includes an insulated, dedicated sensing electrode, separate from the sparking electrode of a spark plug. The sensing electrode may also be shielded to further reduce interference such as electromagnetic interference (EMI). The use of a dedicated electrode allows for ion current measurement with less electromagnetic noise from the ignition process, and also eliminates the need for circuitry that is typically necessary when the sparking electrode is also used to sense ion current.