A piezoresistive pressure-measuring plug for a combustion engine

摘要

A piezo-resistive pressure-measuring plug (100) for a combustion engine for measuring a pressure is disclosed. The piezo-resistive pressure-measuring plug (100) comprises:
a plug body (106, 108, 110) for insertion into a cylinder of the combustion engine, a rod (102) that is arranged in the plug body (106, 108, 110), a sensing structure (104) comprising a piezo-resistive element, that is arranged between the rod (102) and the plug body (106, 108, 110) 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 (102) 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 (102) relative to the plug body (106, 108, 110) so as to apply a force to the sensing structure (104). The measuring plug further comprises an elongated hollow body part (142) at an end linked to the plug body part comprising a scaling surface part (134) wherein the elongated hollow body part (142) friction free extends in the plug body, and the sensing structure (104) is attached to an end of the lower body part (110) opposite to the end linked to the sealing surface part (134).