| 摘要 |
In a state in which the engine is unloaded and the number of engine rotation is low, an overlap period of time during which the intake valve and the exhaust valve are both open is extended during the cold time, as compared with during the warm time. The extension of the overlap period of time causes gases remaining in the cylinders to increase, thereby making the burning of the fuel slow and elevating the temperature of the exhaust gases to thereby elevate the temperature of the cylinder head of the engine. A variation in the number of engine rotation, particularly a decrease in the number of engine rotation, resulting from the increase in the residual gases can be prevented by increasing the amount of intake air. Further, the temperature of the cylinder head can be elevated due to an increase in the amount of the supplied fuel resulting from the increase in the amount of the intake air. |
