Abstract: A ceramic sheathed-type glow plug, whose ceramic heating element is made of an electrically conductive conducting layer and an electrically insulating layer, is described. The conducting layer is made of lead layers and a heating layer. The higher specific electrical resistance of the heating layer allows the temperature of the heating layer and the combustion chamber to be determined. The electrical contact between a connector element and the heating element is established by a contacting element, which is in the form of a pellet made of an electrically conductive powder.

Abstract: A sheathed-element glow plug to be mounted in a combustion chamber is proposed, a rod-shaped heating element being situated in a concentric bore hole of the housing. The heating element has a first current-carrying layer (11), a second current-carrying layer (12), and an insulating layer (15), the insulating layer (15) separating the first current-carrying layer (11) and the second current-carrying layer (12). The first current-carrying layer (11) and the second current-carrying layer (12) being connected at the end of the heating element on the combustion chamber side by a conducting-layer crosspiece (13). The first current-carrying layer (11) and the second current-carrying layer (12) are different lengths, the cross section of the first current-carrying layer (11) in a first section (21) at the end of the heating element away from the combustion chamber being greater than the cross section of its remaining length, and the second current-carrying layer (12) not extending into the first section (21).

Abstract: A sheath heater in a sheathed-type glow plug for diesel engines is described, having at least one generally internal insulation layer and at least one generally external conductive layer, both layers making up a ceramic composite structure. The sheath heater has a generally uniform overall cross-section, generally over its entire length, and, in the area of a tip of the sheath heater, the proportion of the insulation layer in the overall cross-section increases, whereas the proportion of the conductive layer in the overall cross-section decreases.