Ignition timing control system for an internal combustion engine

摘要

A pulser waveform from a pulser coil 2 provided on the side of an engine 1 are shaped by a pulser circuit 3 and then forwarded to a CPU 4 to which a rewritable non-volatile memory 5 for storing ignition timing values is connected. Between the pulser coil 2 and the pulser circuit 3 is provided a mode selection switch SW1 so that when entering a maintenance mode, the voltage of a battery 6 is input to the pulser circuit 3 instead of the pulse signals from the pulser coil 2. Evaluating the pulse width of the shaped pulse signal from the pulser circuit 3, the CPU 4 selectively enters a usual ignition control mode or the maintenance mode. <IMAGE>