Patent ID: 8297115

Claim:
A piezoresistive pressure-measuring plug for a combustion engine comprising: a plug body insertable into a cylinder of the combustion engine, a rod that is arranged in the plug body, and a sensing structure that is arranged between the rod and the plug body, and in such a way that the sensing structure is acted upon, in use, by the pressure prevailing in the combustion chamber of the cylinder, whereby the rod transmits the pressure in the combustion chamber of the cylinder to the sensing structure due to the pressure in the combustion chamber leading to an axial motion of the rod relative to the plug body so as to apply a force to the sensing structure, wherein the sensing structure is integrated and located in the plug body and a piezoresistive element mounted on the sensing structure provides a resistance change when the rod is moved in axial, wherein the plug further comprises a Printed Wiring Board (PWB) carrying sensor electronics for measuring and conditioning the resistance change, wherein the PWB is arranged in the plug body, and wherein the plug body comprises a threaded body part, and wherein the PWB is arranged in the threaded body part.