| 摘要 |
PURPOSE:To enable a radio noise to be prevented in an ignition device and enable its size to be decreased, by using a piezo-electric transformer, in which plural sheets of plate-shaped piezo-electric elements and a center electrode are connected through a conductive resilient member or a fine space, as a high voltage generating source of the ignition device. CONSTITUTION:An output pulse of pulse-state output voltage waveform (a) generated from a piezo-electric transformer driving circuit 29 starts vibration in the vicinity of the top dead center of compression in a cylinder at every one time per two revolutions of an engine, and piezo-electric transformer 11, if it receives this pulse in the thickness direction, generates a strong mechanical vibration in the lengthwise direction over the center part serving as a node point. A piezo-electric effect caused by this vibration generates an electric charge in the lengthwise direction, and alternate high voltage as shown by (b) in the drawing is generated in a gap, that is, an electric discharge gap between an center electrode 16 and an earth electrode 19 through an electrode plate 12, conductive spring 26, conductive upper 27, stem 28 and a seal glass 17. Here an ignition device promotes a preventive effect of its radio noise further can be formed into a small unit because a fine space is provided between the electrode plate 12 and the conductive upper 27. |
