unsplit crank case

例句：

1. 1. The engine's performance is greatly improved by theunsplit crank case design.
   这种不分离的曲轴箱设计大大提升了发动机的性能。
2. 2. The mechanics of this engine arecomplex due to its unsplit crankcase.
   由于其不分离的曲轴箱，这台发动机的工作原理相当复杂。
3. 3.The unsplit crank case allows forbetter access to the engine components during maintenance.
   不分离的曲轴箱在维护时能更好地访问到发动机部件。