REVOLUTIONS DETECTOR FOR INTERNAL COMBUSTION ENGINE

摘要

PURPOSE:To achieve an accurate detection of revolutions regardless of whether a DC-DC converter is operating or not by checking the revolutions based on current flowing through a wake circuit having a secondary winding of an ignition coil and the converter. CONSTITUTION:An impedance Z for detecting a discharge current is connected in series to the ground side of a DC-DC converter 6 which spplies an additional current in series to a secondary winding 12 of an ignition coil 1 overlapping the discharge current. A voltage waveform across the impedance Z is shaped in the form with a waveform shaping circuit F and applied to a revolutions detection module 9 as a similar waveform for detecting a discharge current regardless of the use of the converter 6. This enables accurate detection of revolutions whether the DC-DC converter operates or not. The result is also the same when the output of the circuit F is applied to the module 9 overlapping the terminal voltage on the primary side of the coil 1.