There is known a technology for detecting the occurrence of a misfire in each of cylinders of an engine. See, Japanese Laid-Open Patent Publication No. 2009-280082 (hereinafter referred to as “JP2009-280082A”). According to JP2009-280082A, when a management ECU (117) judges that a misfire has occurred in an internal combustion engine (107), the management ECU turns on a warning lamp (125) (see paragraph [0027]).
There also is known a technology for detecting an abnormal compression pressure in each of cylinders of an engine. See, Japanese Laid-Open Patent Publication No. 2004-019465 (hereinafter referred to as “JP2004-019465A”). According to JP2004-019465A, while a fuel system and an ignition system are inactivated, the engine is cranked in order to rotate a crankshaft (1a), and a rotational variation of the engine is detected using a difference between instantaneous rotational speeds at preset crankshaft angles in compression strokes of the cylinders. An abnormal compression pressure is detected based on the rotational variation (see claims 1 through 6).