IGNITION DEVICE FOR AN INTERNAL COMBUSTION ENGINE

摘要

A booster (2) constituted by a transformer of piezoelectric elements, in which input electrodes (7, 8) are provided in a direction of thickness by combining a primary side piezoelectric element (5) and a secondary side piezoelectric element (6) and an output electrode (9) is provided in a direction of length, is incorporated in a plug cap (3). This plug cap (3) is placed over an end of an ignition plug (4). In this state when a primary voltage, having a waveform similar to the natural resonance frequency of the piezoelectric elements or its component waveform, is applied from a primary voltage generating means (1) to the input electrodes (7, 8), the booster (2) directly sends a high secondary voltage to the ignition plug (4) from the output electrode (9) due to the piezoelectric effect, and a spark discharge is effected in a discharge gap in a combustion chamber. This construction can make the ignition device smaller and lighter and reduce the production costs.