Abstract: The invention relates to a pressure-measuring plug for a combustion engine comprising a plug body with a body tip section facing in use the combustion chamber and comprising a passage, a ring-shaped sensing structure comprising an outer section, an inner section and an annular diaphragm, the plug body being attached to the outer section, a circular membrane comprising an outer part coupled to the outer section and an inner part coupled to the inner section, the membrane provides a sealing protecting the annular diaphragm against the harsh environment in a combustion chamber; and, a plug chamber formed by the circular membrane and the body tip section wherein the passage of the body tip section provides an open connection between the plug chamber and the combustion chamber. The passage is part of a channel structure which functions as a soot filter.

Abstract: The invention relates to a pressure-measuring plug for a combustion engine comprising a plug body with a body tip section facing in use the combustion chamber and comprising a passage, a ring-shaped sensing structure comprising an outer section, an inner section and an annular diaphragm, the plug body being attached to the outer section, a circular membrane comprising an outer part coupled to the outer section and an inner part coupled to the inner section, the membrane provides a sealing protecting the annular diaphragm against the harsh environment in a combustion chamber; and, a plug chamber formed by the circular membrane and the body tip section wherein the passage of the body tip section provides an open connection between the plug chamber and the combustion chamber. The passage is part of a channel structure which functions as a soot filter.

Abstract: A piezoresistive pressure-measuring plug for a combustion engine for measuring a pressure. The piezoresistive pressure-measuring plug: includes a plug body for insertion into a cylinder of the combustion engine, a rod that is arranged in the plug body, a sensing structure comprising a piezoresistive element, that is arranged between the rod and the plug body such that the sensing structure is acted upon, when in use, by the pressure prevailing in the combustion chamber of the cylinder. The sensing structure is arranged in the plug body and, when in use, is compressed in an axial direction by the force applied to the sensing structure and a piezoresistive element mounted on the sensing structure. A PWB is also arranged in the plug body. Such a pressure-measuring plug provides improved bandwidth and reduced build-in height.

Abstract: A piezoresistive pressure-measuring plug (100) for a combustion engine for measuring a pressure is disclosed. The piezoresistive 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 piezoresistive 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) and a PWB (114) provided with sensor electronics for measuring and conditioning a resistance change.