| 摘要 |
<p>PROBLEM TO BE SOLVED: To accurately determine a combustion state from an ion current even when an internal combustion engine has lean combustion with lean fuel or combustion with a large quantity of EGR.SOLUTION: A second ignition coil 10b performs electric discharge from a second ignition plug 70b into a cylinder 110 at a closer position to on an advance side than the execution of fuel injection from an injector 150, and an ion current between the electrodes of the second ignition plug 70b is detected, which is generated by combustion in which electric discharge of a first ignition plug 70a provided on an intake side of the cylinder 110 propagates from combustion near the first ignition plug 70a to an exhaust side of the cylinder 110. Secondary coils 30a, 30b of the first and second ignition coils 10a, 10b are connected to ion current detection means 80 via switch elements 90a, 90b and are brought in conduction with the ion current detection means 80 or a ground through switching of contacts.</p> |
