| 摘要 |
PURPOSE:To assure accurate ignition timing even under variations of engine rpm by resetting in succession the contents of a timer for counting ignition timing based on time duration of a newer stage. CONSTITUTION:A microcomputer 1 restricts one period of a reference pulse (a) generated at prescribed angle for each ignition cycle by a period of a crank angle signal (b) to divide it into a plurality of stages. In addition, the microcomputer specifies one stage in front of an ignition zone and estimates the number of counts from ignition to ignition timing based time duration and an ignition angle of a newest stage adoptable as to the specific stage. Thereafter, the microcomputer starts counting as the specific stage is initiated, and changes a stage to take out time duration to the newest one for every succeeding new stage initiation. It thus obtains ignition timing with use of new counts from the new stage initiation to the ignition timing. Thus, accurate ignition timing can be assured irrespective of variations of the engine rpm. |
