Abstract: An igniting apparatus for an internal combustion engine includes an ignition time calculating section for generating ignition time data Km based on a reference position signal, a section for measuring a previous cycle reference interval required time Tp2 between reference positions associated with a target ignition time, a section for measuring a previous cycle period TN2 for one rotation of the engine through the reference positions, a section for calculating a load state KL2 of the engine based on the previous cycle required time period Tp2 and the previous cycle period TN2, a section for measuring a current cycle period TN4 for one rotation of the engine through the reference positions, and a section for converting the ignition time data Km into a time Ta controlled for the ignition time based on the load state KL2 and the current time period TN4.

Abstract: An ignition apparatus for an engine includes an ignition switch and a monitor switch connected to a battery. A power supply circuit generates a reset signal for a microcomputer in response to closing of the ignition switch. A monitor signal generating circuit generates a monitor signal for the microcomputer in response to closing of the monitor switch. The microcomputer enables ignition to take place only if the monitor signal has a prescribed value when the reset signal is generated. The timing of the reset signal and the timing of the monitor signal are chosen so that the microcomputer will enable ignition only if the ignition switch and the monitor switch are closed substantially simultaneously and will prevent ignition when the switches are closed sequentially, such as when the switches are hot-wired.