Podcast
Questions and Answers
What is the purpose of adjusting the engine signal in a testing mode?
What is the purpose of adjusting the engine signal in a testing mode?
To reduce the overspeed setting by a fixed amount
Why is it important to have a 2nd person standing by during full tests after major overhauls?
Why is it important to have a 2nd person standing by during full tests after major overhauls?
To manually shut down the engine in case it runs away
What is the significance of having full test point manifolds at an easily accessible point?
What is the significance of having full test point manifolds at an easily accessible point?
Makes testing all alarm and shut-down points much easier
What is the purpose of the automatic valve in an air start system?
What is the purpose of the automatic valve in an air start system?
How does the pilot air signal the automatic valve to open in an air start system?
How does the pilot air signal the automatic valve to open in an air start system?
What is the function of the non-return valve in an air start system?
What is the function of the non-return valve in an air start system?
Why do many manufacturers opt for air start valves direct into individual cylinders for diesel engines?
Why do many manufacturers opt for air start valves direct into individual cylinders for diesel engines?
What is the potential risk associated with air start systems if key equipment fails?
What is the potential risk associated with air start systems if key equipment fails?
How can an air start system be tested to ensure it trips at a lower speed?
How can an air start system be tested to ensure it trips at a lower speed?
What are the advantages of using air start valves directly into individual cylinders?
What are the advantages of using air start valves directly into individual cylinders?
What is the preferred method to avoid running a large engine in overspeed conditions?
What is the preferred method to avoid running a large engine in overspeed conditions?
How does the air start system drawing help in understanding potential areas of failure?
How does the air start system drawing help in understanding potential areas of failure?
What are two basic shut-down sensors that marine engines typically come with?
What are two basic shut-down sensors that marine engines typically come with?
Name two other shut-down sensors that can be fitted to marine engines.
Name two other shut-down sensors that can be fitted to marine engines.
What is the purpose of a 'Falling Pressure' switch in the context of marine engines?
What is the purpose of a 'Falling Pressure' switch in the context of marine engines?
Describe how the 'Falling Pressure' switch operates when the pressure falls below a set point.
Describe how the 'Falling Pressure' switch operates when the pressure falls below a set point.
What is a bi-metallic strip used for in the context of temperature sensing?
What is a bi-metallic strip used for in the context of temperature sensing?
Why is it suggested to concentrate on simpler electro-mechanical devices for examination purposes?
Why is it suggested to concentrate on simpler electro-mechanical devices for examination purposes?
What is the purpose of a Crankcase Oil Mist Detector?
What is the purpose of a Crankcase Oil Mist Detector?
Why are safety sensors like Pressure Sensing and Temperature Sensing essential in marine engines?
Why are safety sensors like Pressure Sensing and Temperature Sensing essential in marine engines?
What is the role of a Hydraulic Governor in engine protection?
What is the role of a Hydraulic Governor in engine protection?
What is the purpose of the bi-metallic strip in the context described?
What is the purpose of the bi-metallic strip in the context described?
Why are electronic overspeed devices preferred over mechanical ones?
Why are electronic overspeed devices preferred over mechanical ones?
What happens when the main pin in the mechanical overspeed trip mechanism strikes the plunger?
What happens when the main pin in the mechanical overspeed trip mechanism strikes the plunger?
How does the auxiliary weight behave when the speed of the shaft increases?
How does the auxiliary weight behave when the speed of the shaft increases?
What is the function of the U-Lock Staple in the mechanical overspeed trip mechanism?
What is the function of the U-Lock Staple in the mechanical overspeed trip mechanism?
Why is it important to remove the test setting after conducting an overspeed test on the engine?
Why is it important to remove the test setting after conducting an overspeed test on the engine?
How do electronic overspeed devices eliminate the need for physically running the engine at an overspeed condition during testing?
How do electronic overspeed devices eliminate the need for physically running the engine at an overspeed condition during testing?
What initiates the movement of the main pin in the mechanical overspeed trip mechanism?
What initiates the movement of the main pin in the mechanical overspeed trip mechanism?
Describe the role of the adjusting nut in the mechanical overspeed trip mechanism.
Describe the role of the adjusting nut in the mechanical overspeed trip mechanism.
What is the purpose of the feedback link in a governor system?
What is the purpose of the feedback link in a governor system?
Define 'Gain' in the context of governors.
Define 'Gain' in the context of governors.
How does an electronic governor differ from a mechanical governor?
How does an electronic governor differ from a mechanical governor?
What components are involved in an electronic governor system?
What components are involved in an electronic governor system?
How does the comparator contribute to the operation of an electronic governor system?
How does the comparator contribute to the operation of an electronic governor system?
What is the role of the actuator in an electronic governor system?
What is the role of the actuator in an electronic governor system?
Why is it important for an electronic governor system to sense overspeed?
Why is it important for an electronic governor system to sense overspeed?
How do voltage and current transformers contribute to the functioning of an electronic governor system?
How do voltage and current transformers contribute to the functioning of an electronic governor system?
Explain the purpose of paralleling lines to other units in an electronic governor system.
Explain the purpose of paralleling lines to other units in an electronic governor system.
Study Notes
Safety Sensors
- Marine engines typically come with basic shut-down sensors, including low lubricating oil pressure, high cooling water temperature, and overspeed.
- Additional shut-down sensors can be fitted, including high exhaust temperature, high lubricating oil temperature, and low cooling water pressure.
Pressure Sensing
- A "Falling Pressure" switch can be used to detect low lubricating oil pressure.
- The switch operates by a spring forcing a trip lever down, releasing a reset lever, which opens an electrical contact, shutting down the machine.
Temperature Sensing
- A bi-metallic strip can be used to detect high cooling water temperature.
- Overspeeding an engine incorrectly may cause damage.
Overspeed
- Electronic systems can test overspeed without actually overspeeding the engine.
- The engine speed can be electronically adjusted to reduce the overspeed setting by a fixed amount.
- Full overspeed testing requires the engine to be run up to the full overspeed value and must be done with caution.
Air Starting Systems
- Compressed air is used to start the engine in air starting systems.
- Air start valves directly inject air into individual cylinders to turn the engine.
- The system has potential risks of explosion if key equipment fails.
Hydraulic Governor
- The hydraulic governor regulates engine speed by adjusting fuel supply.
- The servo piston is connected to the fuel rack, which reduces fuel supply when the engine speed increases.
- The feedback link moves down, increasing the tension of the speeder spring, which moves the pilot valve back to the neutral position.
Electronic Governor
- Electronic governors sense speed changes and alter fuel to react to that change.
- They provide a finer degree of control, especially in main engines, where they can be interlinked with specific load profiles.
- The electronic governor system consists of speed sensors, a comparator, a control unit, and fuel rack servo.
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Description
Test your knowledge on safety devices used in marine diesel engines with this quiz. Explore topics such as pressure sensing, temperature sensing, overspeed protection, crankcase explosions, and more.
