| 摘要 |
<p>PURPOSE:To correctly detect occurrence of knockings by forming non-polarizing parts at a part exhibiting itself at a connector part of a circular piezoelectric element and its opposite side. CONSTITUTION:A part (x) which exhibits itself at the side of a connector part 17 of a piezoelectric element 8 and a part (y) on the opposite side are formed with non-polarizing part alpha in advance. The non-polarizing part alpha formed on the part (x) is for preventing electric charge from occurring by oscillation transmitted from the connector part 17, while the non-polarizing part alpha formed on the part 9 is for preventing electric charge from occurring from the non- polarizing part alpha by wavy vibration transmitted from an engine. In this constitution, even if the vibration from the connector part 17 is transmitted to the element 8, there is no output occurred thereby preventing occurrence of noise signal due to vibration as well as preventing abnormal signal from being output even if unnecessary wavy vibration generated in the engine is transmitted to the element 8. Therefore output can be generated in response to only normal vertical vibration thereby allowing correct knocking to be detected.</p> |
