| 摘要 |
PURPOSE:To make it possible to detect a reference position with the use of an instruction pressure detecting type ignition timing control device without using a special purpose pulser, etc. by producing a reference position signal when an instruction pressure signal indicates its maximum peak just after start of the engine. CONSTITUTION:When a starter switch 5 is turned on during start of an engine, an one-shot pulse generator 4 delivers a high level pulse having a predetermined time width, which indicates the starting condition of the engine. When a crank shaft is rotated by a starter motor so that the internal pressure of a combustion chamber is raised, and the level of an instruction pressure delivered from an instruction pressure generating circuit 1 exceeds a predetermined level, the output level of a waveform shaping circuit 2 becomes high, and this signal is used as a peak signal. At this time, when a reset pulse from an AND circuit 6 is fed to a ring counter 7 which is therefore set to zero, a reference position signal generating circuit 8 delivers a reference position signal simultaneously with a clock pulse generated at that time. |
