单选题Critical speed in diesel engines occurs when engine torque pulsations become （）Aopposed to the crankshaft rocking coupleBresonant with the crankshaft natural frequencyCcritical fore and aft crankshaft vibrationsDhorizontal whipping motions of the crankshaft
单选题
Critical speed in diesel engines occurs when engine torque pulsations become （）
A
opposed to the crankshaft rocking couple
B
resonant with the crankshaft natural frequency
C
critical fore and aft crankshaft vibrations
D
horizontal whipping motions of the crankshaft
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