| 摘要 |
The engine misfire detection apparatus of the invention successively determines whether a rotational fluctuation difference Nxd360 as a difference between a rotational fluctuation Nxd at a certain crank angle CA of an engine and a rotational fluctuation Nxd at a 360 degree-prior crank angle CA exceeds a predetermined reference value A1 (step S150) and whether a rotational fluctuation difference Nxd720 as a difference between the rotational fluctuation Nxd at the certain crank angle CA and a rotational fluctuation Nxd at a 720 degree-prior crank angle CA exceeds a predetermined reference value B1 (step S160). The engine misfire detection apparatus detects a misfire of the engine upon satisfaction of all conditions regarding rotational fluctuation difference proportions Nja2, Nja3, and Nja4 on the basis of the rotational fluctuation difference Nxd360 (step S200) and all conditions regarding rotational fluctuation difference proportions Njb2, Njb3, and Njb4 on the basis of the rotational fluctuation difference Nxd720 (step S210), when both the rotational fluctuation differences Nxd360 and Nxd720 exceed the respective reference values A1 and B1 (steps S150 and S160). This arrangement ensures adequate and accurate detection of an engine misfire during warm-up of a catalyst included in an exhaust emission control unit with a significant delay of the ignition timing in the engine. |
