AME 10 Q3

Correct Answer: D) Outlet coolant temperature

Explanation:
In a cascade control system, the secondary controller's setpoint is often the outlet coolant temperature, which is the temperature of the coolant as it exits the engine. By controlling this specific temperature, the system ensures that the coolant remains within the desired range, providing effective cooling to the engine.

Answer: B) It minimizes temperature fluctuations more effectively

Explanation:
Cascade control is preferred because it provides more precise control over the system by using two controllers: the primary controller (which sets the overall temperature goal) and the secondary controller (which manages immediate disturbances). This dual-layer control minimizes temperature fluctuations, keeping the coolant temperature more stable compared to single-loop control, where only one controller handles all tasks.

Correct Answer: B
Explanation: The correct answer is B because cascade control uses two control loops: the primary loop for regulating the coolant temperature and the secondary loop for controlling a related variable (e.g., coolant flow) to enhance the system's stability and responsiveness.

Answer: B) It provides a faster response to disturbances

Explanation:
In a cascade control system, the secondary controller responds directly to disturbances that affect the coolant temperature, such as changes in engine load or ambient temperature. This allows the system to react more quickly and effectively to keep the coolant temperature stable. The primary controller, which controls the overall temperature, benefits from this faster response, leading to better overall control and stability.

Answer: C) It adjusts the flow of coolant to maintain the desired temperature

Explanation:
The secondary controller in a cascade control system is responsible for fine-tuning the flow of coolant through the system. It does this by adjusting valves or pumps based on the feedback it receives, ensuring that the coolant temperature at the engine outlet stays within the desired range. This precise control helps maintain optimal engine performance and prevents overheating.