| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a multi-cylinder engine capable of controlling the residual amount of high-temperature exhaust air in a cylinder to be small in a low-speed high-load range while leaving a large amount of high-temperature exhaust air in the cylinder in a low-speed low-load range. <P>SOLUTION: There is provided a passage state changing means 55f which is capable of changing the exhaust distribution state in an exhaust manifold 50 into: a first state in which exhaust air in each independent exhaust passage 52 passes through a passage with its flow passage area being smaller toward the downstream side; and a second state in which exhaust air in each independent exhaust passage 52 passes through a passage with its flow passage area being larger than that in the first state; wherein the flow passage area of the passage, through which the exhaust air in each independent exhaust passage 52 passes before flowing in a common exhaust passage 50a, can be continuously changed. In the low-speed high-load range A1, the distribution state is set to be the first state and the valve reopening operation of an exhaust valve is stopped. In the low-speed low-load range A2, the distribution state is set to be the second state and the valve reopening operation of the exhaust valve is executed. On the other hand, in a middle-load range A3, the flow passage area of the exhaust passage is decreased as load is increased. <P>COPYRIGHT: (C)2013,JPO&INPIT |
