Apparatus and method for testing a spark plug mounted in an internal combustion engine, including the detection of a cracked ceramic insulator

摘要

A device (100) for testing a spark plug (10) after the spark plug is mounted in an internal combustion engine (40), the spark plug (10) having a center electrode (16) surrounded by an insulator (14) and a terminal end (12 ) and having a side electrode (22) electrically connectable to an electrical ground (48) and configured to form a spark plug gap (30) between the center electrode (16) and the side electrode (22) the device (100) comprises: a high voltage test probe (150) for mechanically testing the spark plug (10) and a non-electrically conductive portion (152) having an electrically conductive ring (172) substantially shielded by the non-electrically conductive portion (152) and a high voltage contact member (170) for electrically connecting to the terminal end (12) of the spark plug (10); and a high voltage control box (110) having a high voltage source (130) and an electrical ground (140) and having: an isolator rupture detection circuit (182) for connecting the high voltage contact element (170) to the electrical ground (140) and the electrically conductive ring (172) to the high voltage source (130) to produce an isolator rupture detection signal (194) indicates whether an insulator (14) is cracked, and a spark plug lighting circuit (180) for connecting the high voltage contact element (170) to the high voltage power source (130) to ignite the spark plug (19) in an ignition test and to generate a spark ignition signal (192) indicating whether the spark plug gap (30) is within specification.