Patent ID: 6474273
Filing Date: 2002-11-05
Classification: F01L,F02D,F02P

Abstract:
A control system for an internal combustion engine comprising a rotational direction change-over switch to be operated when a rotational direction of the two-cycle internal combustion engine should be reversed and a microcomputer to perform a speed reduction step to reduce a rotational speed of said internal combustion engine when said rotational direction change-over switch is operated, an over-advance angle control step to advance an ignition position of said internal combustion engine to an over-advance position when said rotational speed is reduced to less than a set value, a rotational direction judgment step to judge the rotational direction to confirm whether the rotational direction of said internal combustion engine is reversed by said over-advance angle of said ignition position and a reversion initial ignition step to ignite said internal combustion engine at the low speed ignition position in the condition of reversing said rotational direction when the reversion of said rotational direction is confirmed, said control system further comprising an AC magneto generator constructed to generate an AC output voltage of 2n cycles (â€œnâ€  is an integral number of more than 1) per revolution of said internal combustion engine with a phase of said AC output voltage being set so that either of zero cross points of said AC output voltage corresponds to said low speed ignition position on the reverse rotation of said internal combustion engine; a single signal generator constructed to generate a pulse signal of one of the polarities and a pulse signal of other polarity in synchronization with said rotation of said internal combustion engine with generation positions of said pulse signals being set so that said pulse signals of one polarity and of other polarity are generated at said low speed ignition position on the forward direction of said internal combustion engine and at the position advanced relative to said low speed ignition position, respectively and so that the polarity of one half wave of said AC output voltage of said magneto generator when said pulse signal of one polarity is generated is identical to the polarity of one half wave of said AC output voltage of said magneto generator when said pulse signal of other polarity is generated; and said microcomputer adapted to judge said rotational direction of said internal combustion engine from the polarity of said half wave of said AC output voltage when said single signal generator generates said pulse signal of either polarity.