Patent attributes
An internal combustion engine, which can improve an annual energy consumption efficiency, is provided. A gas engine 1 includes: an oil cooler 11 having a passage via which heat is exchanged between engine cooling water and lubricating oil; and a control unit 12 configured to control a temperature of the engine cooling water to a constant temperature so as to cool the lubricating oil during high load operation and to heat the lubricating oil during low to medium load operation. The control unit 12 increases the temperature of the engine cooling water during low to medium load operation compared with the temperature of the engine cooling water during high load operation. An oil jet 18a, which is configured to inject the lubricating oil into a rear surface of a piston 17, is provided.
