| 摘要 |
PURPOSE:To enable a lag angle width to be appropriately set in high speed range by controlling the primary current control switch by means of the former half cycle signal out of a signal coming from a signal coil which generates one cycle signal per one ignition cycle at the set rate of rotation completing a lag angle. CONSTITUTION:An ignition position control circuit 20, controlling a thyrsitor 3 as the primary electric current control switch for an ignition coil 1, is composed by providing a signal coil 23, which generates a control signal synchronizing with the engine speed and a signal supply circuit, consisting of a resistance 26 and a diode 27 which generate a control hignal different from that of the signal coil 23. A collector of a signal supply control transistor Tr31 is connected to one end of said resistance 26. Further, lag angle control condensers 41, 42 charged through constant-current circuits 20A-20C are provided and terminal voltage of said condensers are compared with reference voltage by means of comparison circuits 53, 59 to place control signals from the signal supply circuit on ON/OFF state. Furthermore, a circuit 71 for deciding a lag angle ending position is provided to control the abovementioned Tr31. |
