Diesel Engines 1

Question 1

What is happening during the induction stroke.

Answer 1

The inlet valve is open
The exhaust valve is closed
The piston is moving from top dead center to bottom dead centre sucking air in to the cylinder through the air intake.

Question 2

What happens during the compression stroke?

Answer 2

Both valves are closed
The piston moves from bottom dead centre to top dead center compressing the air causing it to heat up then the injector sprays atomised fuel in to the cylinder just before the piston reaches TDC.

Question 3

What happens during the power stroke?

Answer 3

After the fuel is injected it has a ignition delay before combusting forcing the piston down to bottom dead center turning the crankshaft.

Question 4

What happens during the exhaust stroke?

Answer 4

The exhaust valve is open
The intake valve is closed
The piston moves from bottom dead centre to top dead centre to force the exhaust gases out of the exhaust manifold.

Question 5

What is valve overlap and why do we use it?

Answer 5

Valve overlap is when the intake valve opens slightly near the end of the exhaust to push out all of the exhaust gases and cool the exhaust valve to prevent deformation

Question 6

What are diesel engines used for in the RN?

Answer 6

1.Propulsion
2.Air compressors
3.Generating electricity
4.Fire pumps

Question 7

Define the driven end of a engine.

Answer 7

The end of the engine with the flywheel which is connected to a load like a gearbox

Question 8

Define the free end of a engine.

Answer 8

The end that is used to power ancillaries and control timing of them

Question 9

What is the compression ratio of a desiel engine.

Answer 9

20:1

Question 10

What does the engine block do?

Answer 10

It is the main body of the engine housing the cylinders and mounting ancillary components.

Question 11

What is the job of the cylinder?

Answer 11

To be the compression chamber and dissapate heat from the piston and power stroke to the engine block.

Question 12

How are cylinders labeled for inline engines?

Answer 12

They are labelled in series from the free end of the engine.

Question 13

How are cylinders labelled in a v-engine?

Answer 13

The cylinders are separated into banks A and B.
Bank A is always on the left when looking from the free end the cylinders are the labeled in series in each bank

Question 14

What is the role of the cylinder head?

Answer 14

To close of the combustion chamber and house the valves and fuel injectors.

Question 15

What is the role of the cylinder head gasket?

Answer 15

A gasket between the cylinder head and engine block to prevent gas or fluid leaking it is also reinforced in high pressure areas with soft metals.

Question 16

Why do we need a sump in a engine?

Answer 16

So that we can collect and reuse oil draining from the rocker gear and crankshaft.

Question 17

What is the role of a piston?

Answer 17

To compress and draw gas into the cylinder.

Question 18

Why are piston rings important?

Answer 18

They create a seal between the piston and cylinder to prevent gases and oils mixing which could lead to improper combustion.
2 to control pressure
1 to control oil and lubricant the cylinder

Question 19

What is the role of the gudgeon pin?

Answer 19

To connect the piston to the connecting rod.

Question 20

What is the role of the connecting rod?

Answer 20

To connect the piston to the crankshaft.

Question 21

What is the role of the crankshaft?

Answer 21

To convert the reciprocating motion from the piston to rotary motion which can be used by the load on the engine.

Question 22

What is the role of a flywheel

Answer 22

To help the engine turn over the other cylinders when they are not on there power stroke and smooth out the rotary motion
Has gear teeth on the outside for the starter motor to mesh with.

Question 23

What is the role of the camshaft?

Answer 23

To spin exactly half the speed of the crankshaft to control the timing of the valves opening and closing.

Question 24

What is the role of a valve and the two types?

Answer 24

Used to control the flow of fresh air and exhaust gases in the cylinder.
Exhaust valve
Intake vavle

Question 25

What is the role of the push rods?

Answer 25

To transfer the motion of the camshaft to the rocker Arms?

Question 26

What is the role of the rocker Arms?

Answer 26

To open the valves at the correct time.

Question 27

What is the role of the fuel injector

Answer 27

To spary a controlled volume of high pressure atomised fuel into the cylinder at the end of the compression stroke

Question 28

What is the oil test we use called and what does it test for?

Answer 28

Kittewake oil test kit
Water
Insouables
Acidity
Viscosity

Ruling oil between fingers
Abrasives

Question 29

What 3 things are we checking when testing coolant?

Answer 29

1.salinty (salt content)
2.density
3.acidity

Question 30

What happens when both lube oil and coolant pressure are low?

Answer 30

A alarm is set off and if pressure falls below safe limits the engine will trip.

Question 31

What happens if the lube oil and coolant temperature is high?

Answer 31

A alarm will sound then if temperature rises above a safe limit the engine will trip.

Question 32

What happens when the engine overspeed?

Answer 32

A alarm will sound and if it continues to occur the engine will trip.

Question 33

What is the procedure to rest a trip

Answer 33

Find the cause
Fix the cause
Get permission to rest the trip
Rest the trip

Question 34

What safety system is fitted in all engine rooms and machine spaces?

Answer 34

Fire detection systems and remote or local fire suppression systems.

Question 35

Why is hygiene important when working with engines?

Answer 35

To prevent skin infections and reduce risk of fire from oil spills or soiled rags/overalls.

Question 36

What are the hazards of working with engines?

Answer 36

Noise
Fire
Entrapment
Heat

Question 37

What is the name and use of the antifreeze used in the RN?

Answer 37

AL39
It is a corrosion inhibitor