Patent ID: 6927362

Claim:
A sheathed element glow plug having an ionic current sensor, comprising: a housing having a concentric bore; and a rod-shaped heating element arranged in the concentric bore, the heating element including at least one insulation layer, a first feeder layer, a second feeder layer, and a web, the first feeder layer and the second feeder layer connected by the web on a combustion chamber-side end of the heating element, the first and second feeder layers and the web made of an electrically conducting ceramic material, the insulation layer made of an electrically insulating ceramic material, wherein (a) the heating element includes a single ionic current detection electrode made of an electrically conducting ceramic material and not connected to the first and second feeder layers; and (b) the first and second feeder layers are arranged to operate as ionic current detection electrodes, an electrical voltage having a same voltage potential being applied to the first and second feeder layers for ionic current detection.