单选题关于四冲程柴油机进、排气凸轮的布置说法正确的是（）。A进排气凸轮在圆周方向不重叠B非增压柴油机重叠25°～50°C增压柴油机重叠40°～65°D非增压柴油机重叠40°～65°
单选题
关于四冲程柴油机进、排气凸轮的布置说法正确的是（）。
A
进排气凸轮在圆周方向不重叠
B
非增压柴油机重叠25°～50°
C
增压柴油机重叠40°～65°
D
非增压柴油机重叠40°～65°
参考解析
解析：
四冲程非增压机的气阀重叠角为25～50，增压机的气阀重叠角为80～130根据四冲程机曲轴转速与凸轮轴转速为2：1的关系，可知非增压柴油机重叠12．5～25凸轮转角，增压柴油机重叠40～65凸轮转角
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