| 摘要 |
PROBLEM TO BE SOLVED: To reduce the generation frequency and level of corona discharge noise after a corona discharge, in a system for detecting, via an electrode of a spark plug, an ion current generated in combustion of an internal combustion engine. SOLUTION: Plus voltage and minus voltage are alternately impressed in a predetermined period on a central electrode of the spark plug by a multiple igniter in a combustion stroke of the internal combustion engine, and an air-fuel mixture is burnt by multiply igniting so as to alternately repeat plus ignition and minus ignition, and the ion current generated in response to its combustion is detected via the spark plug. In this case, the multiple igniter performs multiple ignition so that the final ignition polarity of the multiple ignition always becomes the plus ignition. Thus, since the final ignition polarity of the multiple ignition always becomes the plus ignition, electrifying polarity of an insulator part of the spark plug after finishing the multiple ignition, always becomes minus polarity. Thus, the generation frequency and the level of the corona discharge noise after finishing the multiple ignition, can be effectively reduced. COPYRIGHT: (C)2008,JPO&INPIT
|
