Knock detector for internal combustion engine has surface micromechanical acceleration sensor element with two capacitors, where capacitance variation can be used to detect knocking

摘要

The detector has a surface micromechanical acceleration sensor element with two capacitors. The capacitance variation of the sensor can be used to detect knocking in the engine. The sensor element preferably has a given number of combed tongues (11-13,15-19) that intermesh and are assigned to fixed electrodes (20-23), to form varying capacitances. An evaluation circuit has at least one capacitance to voltage converter.