Assertion: engine | /r/CapableOf | rotate in opposite directions
Facets:
value: to offset the differences
type: PURPOSE
value: at twice the crankshaft's speed
type: MANNER
Source sentences:
text: In a system invented by Dr. Frederick W. Lanchester in 1911, an inline-four engine uses two balance shafts, rotating in opposite directions at twice the crankshaft's speed, to offset the differences in piston speed.