Sheathed-element glow plug for internal combustion engines

A sheathed-element glow plug is proposed for the ignition of fuel vapour-air mixtures in internal combustion engines. The sheathed-element glow plug conventionally has a metal tube enclosing the section of a glow tube remote from the combustion space and having an electrical resistance heating element in its interior; this heating element is connected on the terminal side to an insulated connection bolt led out of the housing, attached to the floor of the glow tube on the ignition side and preferably embedded in an electrically insulating material which conducts heat well. The exterior of the glow tube floor is provided according to the invention with at least one depression (blind hole and/or slot), in which a contacting of the fuel vapour-air mixture to be ignited takes place and the ignition temperature of the fuel vapour-air mixture is thereby lowered in the order of magnitude of 100 DEG C; in addition, due to the reduced ignition temperature, the time taken to heat up the sheathed-element glow plug is shortened and the load on the on-board battery is reduced.