Misfire sensor

摘要

A sensor element for detecting misfire in an internal combustion engine includes: a detecting unit including a piezoelectric film consisting essentially of a ceramic material, a first electrode coated onto at least a portion of the outer surface of the piezoelectric film, and a second electrode coated onto at least a portion of the inner surface of the piezoelectric film; a vibrating portion consisting essentially of a second ceramic material, the detecting unit being placed on the vibrating portion so that the second electrode is coated onto at least a portion of the vibrating portion; and a fixing portion for fixing the vibrating portion so that the vibrating portion may vibrate. In the misfire sensor, the piezoelectric film converts the sound of a combustion explosion into an electric signal. The misfire sensor is excellent in precise misfire detection and durability at low cost.