AME 11 End of Unit – SVE Study

AME 11 End of Unit Quiz

1 / 12

With reference to engine governors, explain isochronous governing.

B) Isochronous governing allows the engine speed to fluctuate slightly around the set point to accommodate load changes. Reason: This describes droop control rather than isochronous governing, where slight fluctuations are acceptable.

C) Isochronous governing adjusts the engine speed only during idle periods to maintain stability. Reason: Isochronous governing applies to all operating conditions, not just idle periods.

D) Isochronous governing is a technique where the engine speed is allowed to drift with load changes, optimizing fuel efficiency. Reason: Allowing speed drift with load changes describes a droop control system, not isochronous governing.

A) Isochronous governing ensures that the engine speed remains constant regardless of the load applied, maintaining the same speed even with varying demands. Reason: Isochronous governing is designed to keep the engine speed constant, independent of changes in load.

2 / 12

What happens when the flow out is increased in a system where the water tank level is controlled by a float and lever proportional system?

A) The float rises, causing the control valve to open more to increase the inflow.

B) The float drops, causing the control valve to close, reducing the inflow.

D) The float drops, causing the control valve to open more to increase the inflow.

C) The float rises, causing the control valve to close, reducing the inflow.

3 / 12

2. Which of the following is a typical application of an On-Off control system?

C) Pressure regulation in a hydraulic system.

D) Flow control in a proportional valve system.

B) Temperature control in a household thermostat.

A) Speed control of a variable frequency drive.

4 / 12

What is the relationship between proportional band and gain in a control system?

D) Proportional band and gain are the same thing.

C) Proportional band and gain are independent of each other.

B) Proportional band is inversely proportional to gain.

A) Proportional band is directly proportional to gain.

5 / 12

State with reasons, the type of actuator fitted to the process valves for a lubrication oil cooling system in which the valve diverts the oil through a cooler.

A) Electric Actuator: Reason: An electric actuator offers precise control of the valve position and can be easily integrated with control systems to modulate the oil flow through the cooler as required.

C) Hydraulic Actuator: Reason: Hydraulic actuators are generally used for high-force applications and may be less suitable for the precise control required in diverting oil through a cooler.

B) Pneumatic Actuator: Reason: Pneumatic actuators provide reliable and fast operation and are well-suited for applications requiring frequent adjustments to the valve position, such as diverting oil flow through a cooler.

D) Manual Actuator: Reason: Manual actuators require manual intervention to adjust the valve position, which is not ideal for automatic and precise control of oil flow through a cooler.

6 / 12

What is the primary characteristic of a Discontinuous (On-Off) control system?

A) The output is continuously variable.

C) The system adjusts output in small increments.

B) The output is either fully on or fully off, with no intermediate states.

D) The system provides proportional control based on the error magnitude.

7 / 12

How is the level in a water tank controlled by a float and lever proportional system?

D) The lever controls the water level by switching between two fixed positions—completely open or completely closed.

B) The float sinks as the water level rises, which directly activates a pump to remove excess water from the tank.

C) The float rises with the water level, opening a valve to allow more water into the tank.

A) The float rises with the water level, causing the lever to close a valve, stopping the inflow of water when the desired level is reached.

8 / 12

Explain dead zone in control terms.

B) Dead zone is the time required for a system to stabilize after a disturbance. Reason: This describes settling time rather than dead zone, which is about the unresponsive range in the input-output relationship.

A) Dead zone refers to a range within which changes in input do not produce any change in the output of a control system. Reason: This correctly describes dead zone as a region where the system is unresponsive to inputs within that range.

C) Dead zone is the amount of time it takes for the control system to start responding after a command is issued. Reason: This describes the delay or lag in response, not the concept of dead zone.

D) Dead zone is the ability of a control system to maintain output stability despite fluctuations in the input. Reason: This describes system stability rather than dead zone, which is specifically about input-output response range.

9 / 12

Describe the effect of increasing the controller gain with respect to the steady-state tank level when the outflow is increased in a float and lever proportional system.

C) The steady-state tank level will decrease more slowly in response to the increased outflow.

B) The steady-state tank level will oscillate more and be less stable.

A) The steady-state tank level will become more stable and closer to the setpoint.

D) The steady-state tank level will remain unchanged regardless of the controller gain.

10 / 12

How does hysteresis improve the performance of an On-Off control system?

C) It allows the system to adjust output continuously.

A) It increases the switching frequency of the system.

B) It prevents rapid cycling by creating a dead zone between switching on and off.

D) It enables the system to predict and correct future errors.

11 / 12

In an On-Off control system, what happens when the controlled variable exceeds the set point?

A) The system modulates the output to gradually reduce the variable.

B) The system switches off the output to bring the variable back to the set point.

C) The system increases the output to correct the error.

D) The system remains inactive until the variable drops significantly.

12 / 12

Explain the purpose of Derivative Action.

D) Derivative Action compensates for errors in the system by applying a proportional correction based on the current error value alone.

A) Derivative Action aims to eliminate steady-state errors by continuously adjusting the control output based on the accumulated error over time.

B) Derivative Action helps to anticipate future errors by reacting to the rate of change of the error, thereby improving the system’s stability and response time.

C) Derivative Action adjusts the control output to maintain a constant error, ensuring that the system remains at a fixed setpoint without any fluctuations.

Your score is