| 摘要 |
PROBLEM TO BE SOLVED: To effectively suppress both adhesion of carbon onto an ignition plug at a low temperature and occurrence of preignition at a high temperature.SOLUTION: An internal combustion engine is configured so that a plug cooling flow passage formed near an ignition plug installed in a ceiling portion of each cylinder and circulating therein coolant discharged from a coolant pump is provided separately from a main flow passage circulating therein the coolant discharged from the coolant pump in a cylinder head that constitutes the ceiling portion of the cylinder, a flow volume of the coolant flowing in the plug cooling flow passage is set to 0 or lower than a flow volume of the coolant flowing in the main flow passage if a symptom of preignition in the cylinder is not sensed, and the flow volume of the coolant flowing in the plug cooling flow passage is increased if the symptom of the preignition in the cylinder is sensed as compared with a case in which the symptom of the preignition is not sensed. |
