| 摘要 |
PURPOSE:To prevent consumption of a plug electrode in the ignition method where high voltage is generated in a secondary coil by disconnection of electric conduction in a primary coil, by electrically conducting the primary coil again in the vicinity of the top dead center and interrupting a firing spark. CONSTITUTION:A transistor 5 is turned on by closing of a breaker contact 3 to allow an electric current to flow in the primary side of an ignition coil 10, and turned off by the next opening of the contact, if the primary current is cut off, high voltage is generated at this moment in the secondary side to cause a spark. On the other hand, a position signal of the top dead center (TDC) detected by a sensor 3b of a disc 3a passes through an AND gate 123 together with a pulse, generated in the first monostable multivibrator 122 after the opening of the contact 3, to turn on a power transistor 8, then the high voltage is dissipated at a steep gradient. Simultaneously a transistor 133 is turned on the allow an electric current to flow in the primary coil and charge a capacitor 135, then the current is gradually decreased not to cause high voltage in the secondary side. |
