Engine Terms（发动机术语）
TDC(top dead center) ― the position of the crank and piston when the piston is farther away from the crankshaft.
TDC (上止点) - 当活塞离曲轴最远时，曲柄和活塞的位置。
BDC (bottom dead center) ― the position of the crank and piston when the piston is nearest to the crankshaft.
BDC (下止点) - 当活塞离曲轴最近时，曲柄和活塞的位置。
stroke ― the distance between BDC and TDC; stroke is controlled by the crankshaft.
行程 - 下止点和上止点之间的距离；行程由曲轴控制。
bore ― the internal diameter of the cylinder.
缸径 - 汽缸的内径。
swept volume ― the volume between TDC and BDC.
有效容积 - 上止点和下止点之间的体积。
engine capacity ― this is the swept volume of all the cylinders, e.g. a four-cylinder engine having a capacity of two liters (2000 cm3)
has a cylinder swept volume of 500 cm3.
发动机排量 - 这是全部汽缸的有效容积，例如一台排量为两公升(2000 cm3)的4个汽缸的发动机每一个汽缸的有效容积为500 cm3。
clearance volume ― the volume of the space above the piston when it is at TDC.
间隙容积 – 当活塞位于上止点时，活塞顶上面的气缸空间。
compression ratio = (swept vol + clearance vol)/(clearance vol)
压缩比 = ( 有效容积 + 间隙容积 ) / ( 间隙容积 )
two-stroke ― a power stroke every revolution of the crank.
二冲程 – 曲柄旋转一圈作功一次。
four-stroke ― a power stroke every other revolution of the crank.
四冲程 - 曲柄旋转两圈作功一次。
