1. Field of the Invention
The invention relates to an oil jet system that injects oil toward a piston of an internal combustion engine, and a control method for the oil jet system. Particularly, the invention relates to measures for optimizing the timing of switching between an operated state and stopped state of an oil jet.
2. Description of Related Art
As is described in, for example, Japanese Patent Application Publication No. 61-138816 (JP 61-138816 A) and Japanese Patent Application Publication No. 2010-236438 (JP 2010-236438 A), there is known an engine including an oil jet system that injects engine oil (lubricating oil) (directs an oil jet) toward the back face side of a piston. By cooling the piston with the oil jet, it is possible to suppress an excessive increase in the temperature of the piston.
As control over the oil jet, JP 61-138816 A describes that an oil jet is started when the temperature of the engine oil becomes higher than or equal to a predetermined value, and the amount of oil jet at that time is calculated on the basis of an engine rotation speed and a fuel injection amount.
JP 2010-236438 A describes that an oil jet is stopped when the temperature of coolant of the engine becomes lower than or equal to a predetermined value.