| 摘要 |
PURPOSE:To obtain a satisfactory ignition timing characteristic over a whole engine speed range, by changing the ignition timing along a trapezoidal curve in accordance with changes in engine speed. CONSTITUTION:A chop signal generating circuit II issues a chop-like voltage in synchronism with a timing pulse from a pulser coil 20. Between positive and negative timing pulses generated from the pulser coil 20 in the above-mentioned circuit II, a saw-like waveform voltage having an inclined angle larger than that of the rising part of the chop-like voltage, is generated from a saw-like wave generating circuit III. Further, a comparator circuit IV compares the output voltage of the circuit II with the output voltage of the circuit III, and issues a turning-on signal when the difference between both outputs becomes zero. Due to this turning-on signal, a trigger signal generating section V triggers the gate of a thyristor 13 for ignition. With this arrangement, the ignition timing may be changed along a trapezoidal curve in accordance with changes in engine speed, thereby a satisfactory ignition characteristic may be obtained over a whole engine speed range. |
