Abstract: A spark plug for an internal combustion engine of a motor vehicle; the spark plug is embodied with a generally essentially long shape and includes: an essentially capacitive lower part including two coaxial electrodes, one of which is a central electrode, and the other a threaded shell for screwing in the spark plug on the engine; and an essentially inductive upper part including a central winding including a plurality of coils wound around a coaxial mandrel, an envelope, and an insulator inserted between the envelope and the winding. The essentially capacitive part and the essentially inductive part are mechanically interconnected as to enable transmission of a clamping couple applied to the envelope to the essentially capacitive lower part. The mandrel can be elastically deformed as to compensate effects of dilation of the insulator.

Abstract: A radiofrequency plasma spark plug configured to equip a combustion chamber including: an annular shell with a main axis; a central electrode made of a conductive material, extending along the main axis and including an inner portion arranged inside the annular shell and an outer portion arranged outside the annular shell: an annular electrically insulating part extending at least about the inner portion of the central electrode so as to be interposed between the shell and the electrode, the insulating part only covering part of the outer portion of the central electrode. The insulating part includes an annular flange concealing the entire circular terminal surface of the shell relative to the uncovered part of the electrode.

Abstract: An essentially-elongated spark plug for an internal combustion engine of a motor vehicle, including: an essentially-capacitive lower part including two coaxial electrodes; an essentially-inductive upper part including a central mandrel, a coaxial winding around the mandrel, and an external tubular casing that serves as electromagnetic armour; and an insulant disposed radially between the casing and the winding. The essentially-inductive upper part includes a second internal casing of electromagnetic armour, which is disposed radially between the insulant and the external casing.

Abstract: Sparkplug (1) for the internal combustion engine of a motor vehicle, of substantially cylindrical overall shape, comprising: —an essentially capacitive lower part (C) comprising: •two coaxial electrodes: an internal electrode of axis (D) termed the central electrode (3) and an external electrode termed the shell (2) surrounding the central electrode (3) •an electrically insulating block termed the insulator (4) inserted between the central electrode (3) and the shell (2), —an essentially inductive upper part (I) comprising: •a central sleeve (8) surrounded by a coil (5), a bottom end part (57) of which surrounds a top end part (31) of the central electrode (3) •an external casing (6), •an insulator (7) inserted radially between the casing (6) and the coil (5) characterized in that the top end part (31) of the central electrode (3) has a coating (9) of material which: —has greater electrical conductivity than the material of the central electrode (3), —has no ferromagnetic properties.

Abstract: A spark plug for an internal combustion engine of a motor vehicle; the spark plug is embodied with a generally essentially long shape and includes: an essentially capacitive lower part including two coaxial electrodes, one of which is a central electrode, and the other a threaded shell for screwing in the spark plug on the engine; and an essentially inductive upper part including a central winding including a plurality of coils wound around a coaxial mandrel, an envelope, and an insulator inserted between the envelope and the winding. The essentially capacitive part and the essentially inductive part are mechanically interconnected as to enable transmission of a clamping couple applied to the envelope to the essentially capacitive lower part. The mandrel can be elastically deformed as to compensate effects of dilation of the insulator.

Abstract: The invention relates to a plasma-generating spark plug which undergoes excitation in the radio frequency domain. The invention comprises at least one first metallic electrode (12, 14), an insulator (13), one of which is equipped with a housing (130) in which the other element (13, 14) is mounted with a gap (15, 16) therebetween. The surface of the insulator (13) opposite the first electrode (12, 14) is metallised.