摘要 |
A misfiring detecting system for an internal combustion engine includes a first misfire determination unit for comparing an engine rotational speed variation amount computed by an engine rotational speed variation amount computing unit, which computes a variation amount of the engine rotational speed, with a misfire determination value set by a misfire determination value setting unit and determines the occurrence of misfiring in the internal combustion engine on the basis of a result of the comparison, and a second misfire determination unit for determining the occurrence of misfiring in the internal combustion engine on the basis of: a result of comparison of a value indicative of a variation between engine rotational speed variation amounts computed by the engine rotational speed variation amount computing unit in the current and immediately preceding cycles, respectively, with a first set value; and a result of comparison of a value indicative of a variation of variation between engine rotational speed variation amounts computed by the engine rotational speed variation amount computing unit in the immediately preceding cycle and that of a two preceding cycle, respectively, with a second set value, so that misfiring can be accurately detected by preventing erroneous misfiring detection.
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