Patent ID: 7444973

Claim:
A glow plug for an internal combustion engine comprising: a generally tubular body ( 8 ) having threads ( 16 ) adapted to engage complementary threads in an engine cylinder head ( 6 ); a finger ( 10 , 10 ′) incorporating a heating element, said finger ( 10 , 10 ′) disposed centrally within said body ( 8 ) and extending from a lower end thereof for exposure within the internal combustion engine ( 4 ); a piezo-electric pressure sensor supported within an upper end of said body ( 8 ); a force transmitting device ( 38 ′) having the form of a tubular member of substantially circular section, said force transmitting device ( 38 ′) comprising a zone ( 40 ) in which its outer diameter increases towards one of its ends, and in that the front face of the device corresponding to that flared end is a bearing face adapted to receive a pressure sensor ( 14 ); and a deformation zone ( 42 , 42 ′) surrounding at least a portion of said finger ( 10 , 10 ′) and directly abutting said force transmitting device ( 38 ′), said deformation zone ( 42 , 42 ′) configured for exposure within the internal combustion engine ( 4 ) for transmitting compression forces resulting from engine ( 4 ) pressure directly to said force transmitting device ( 38 ′).