direct-expansion coil

例句：

1. 1.The direct-expansion coil is used to control the speed of the motor.
   直接膨胀线圈用于控制电机的速度。
2. 2. The direct-expansion coil is an important component of the engine.
   直接膨胀线圈是发动机的一个重要组成部分。
3. 3.The direct-expansion coil helps to reduce noise and vibration in the engine.
   直接膨胀线圈有助于减少发动机中的噪音和振动。