To certainly detect misfire even when there is an operation area that variations in angular velocity when causing the misfire is reduced due to the influence of resonance of a damper or the like.
This misfire diagnostic device for an engine includes: a device 5 having a means measuring time required for a predetermined crank angle zone during a combustion stroke with respect to each cylinder, a means storing a time measured value with respect to each cylinder for every ignition; a means calculating a misfire parameter based on these stored values, and a means determining occurrence of the misfire when the misfire parameter is higher than a predetermined misfire determining threshold; and an operation area detection means 7 detecting an engine operation area. The time measured value is measured in a crank angle zone where the increased amount of the time measured value caused by the misfire in the crank angle zone corresponding to the combustion stroke is relatively increased. When the misfire occurs in the present operation area, determination of the misfire is performed using the misfire parameter calculated based on the time measured value measured in the crank angle zone where the increased amount of the time measured value is relatively increased.
| JPH10259754A | 1998-09-29 | |||
| JP2003286890A | 2003-10-10 | |||
| JP2008069692A | 2008-03-27 | |||
| JPH0968095A | 1997-03-11 | |||
| JP2007170248A | 2007-07-05 |
Masahiro Fujii
Yasunari Mita
Masaaki Iida