During a shift, the World Transmission enters closed-loop control between which of the following points?

During a shift, the World Transmission enters closed-loop control between which of the following points?

• A. Synchronous speed and shift initiation
• B. The WT has closed loop control during the entire shift
• C. Shift initiation and turbine pull down
• D. Turbine pull down detected and synchronous speed

Answer: (D)

The key idea is that speed-control feedback is used only during a specific window of the shift. After the shift starts, the system often uses open-loop or limited feedback during the initiation and the turbine pull-down itself. Once the turbine pull-down is detected, the situation changes: the transmission relies on feedback from actual speed to precisely drive the output toward the target speed. From that moment until the output reaches synchronous speed, the control uses closed-loop behavior to fine-tune the actuation and prevent overshoot or slip as the gear engagement completes. That’s why the window for closed-loop control is from turbine pull-down detection up to achieving synchronous speed.

The key idea is that speed-control feedback is used only during a specific window of the shift. After the shift starts, the system often uses open-loop or limited feedback during the initiation and the turbine pull-down itself. Once the turbine pull-down is detected, the situation changes: the transmission relies on feedback from actual speed to precisely drive the output toward the target speed. From that moment until the output reaches synchronous speed, the control uses closed-loop behavior to fine-tune the actuation and prevent overshoot or slip as the gear engagement completes. That’s why the window for closed-loop control is from turbine pull-down detection up to achieving synchronous speed.