Patent ID: 6494087
Filing Date: 2002-12-17
Classification: F02N,G01M

Abstract:
A system for discriminating a misfire state of an internal combustion engine, comprising:engine operating condition determining means for determining whether an operation of the engine is under a condition, including at least the absence of fuel supply cutoff, that makes misfire determination possible; misfire determining means connected to the engine operating condition determining means for determining that a misfire has occurred in the engine when the engine operation is under the condition that makes misfire determination possible; combustion counting means connected to said engine operating condition determining means for counting a number of combustions of the engine during a period when said engine operating condition makes misfire determination possible; misfire counting means connected to said engine operating condition determining means for counting a number of misfires determined by said misfire determining means; misfire state discriminating means connected to said engine operating condition determining means for comparing the number of misfires counted by said misfire counting means with a reference value when said number of combustions counted by said combustion counting means reaches a predetermined value and for discriminating a misfire state of the engine based on a result of the comparison; and number savings means connected to said engine operating condition determining means for saving the number of combustions counted by said combustion counting means and the number of misfires counted by said misfire counting means, when the engine operation moves from the condition that makes misfire detection possible.