step-up piston spring

例句：

1. 1. The newcar has a step-up pistonthat makes it more efficient.
   这款新车有一个步进式活塞，使其更加高效。
2. 2. Thestep-up piston is designed toreduce friction and improve performance.
   这个步进式活塞的设计是为了减少摩擦并提高性能。
3. 3.The engineer had to replace the old step-up piston with a new oneto fix the problem.
   工程师不得不用一个新的步进式活塞来修复这个问题。