stepless speed regulation

例句：

1. 1.The car's engine has a stepless speed regulation system that allows it to maintain optimal performance at any speed.
   这辆车的发动机有一个无级调速控制系统，它允许它在任何速度下都能保持最佳的性能。
2. 2.The new transmission in the truck has a stepless speed regulation feature that makes shifting gears smoother and more efficient.
   卡车上的新变速箱具有无级调速功能，这使得换挡更加平滑和高效。
3. 3.The engineer used a stepless speed regulation system to optimize the vehicle's performance during high-speed driving.
   工程师使用了一个无级调速系统来优化车辆在高速行驶时的性能。