| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve opening controllability of exhaust control valves A and B in a low opening region. <P>SOLUTION: A straight line AL1 which connects the rotation center C1 of each of the first rotary shafts 61 of the arms 23 and 24 to the rotation center C2 of the connecting rings 25 and 26 (second rotary shaft 62 of the arms 23 and 24) of valves 21 and 22 when the exhaust control valves A and B are fully closed is disposed to cross a straight line AL2 extending perpendicular to the seat surfaces PL1 of valve seats 17 and 18 at an acute crossing angle θ0. Especially, the crossing angle (θ0) where the straight line AL1 and the straight line AL2 cross each other at an acute angle is set within the angle region larger than 0° and smaller than 45°. This makes the opening change (start-up of open valve initial stage) of the exhaust control valves A and B with respect to the change of the rotary angle θ1 of the first rotary shafts 61 of the arms 23 and 24 become gradual. Accordingly, the opening controllability in the low opening regions of the exhaust control valves A and B, especially in the open valve initial stage of the valves 21 and 22, can be improved. <P>COPYRIGHT: (C)2013,JPO&INPIT |
