reversing four way valve

例句：

1. 1. The reversing four way valve is essential for the proper functioning of the engine.
   四通换向阀对于发动机的正常运作至关重要。
2. 2. The technicians had to reverse the four way valve to fix the leak.
   技术人员不得不反向操作四通换向阀来修复泄漏。
3. 3.The engineer tested the reversing four way valve before starting the engine.
   工程师在启动发动机之前测试了四通换向阀。