Diesel Engine Course

Question 1

How does a diesel engine work?

Answer 1

• a reciprocating piston engine
• ignites a compressed fuel-air mixture to create a force that push down on the pistons which in turn push against the crankshaft
• that force creates rotational energy

Question 2

reciprocating

Answer 2

hin- und her

Question 3

crankshaft

Answer 3

Kurbelwelle

Question 4

Biggest difference to petrol engine?

Answer 4

A petrol engine need a spark plug to ignite the fuel-air mixture
A diesel engine auto ignites when a certain temperature and pressure is reached

Question 5

A diesel engine has two main requirements:

Answer 5

Air supply
Clean fuel

Question 6

das Ansaugrohr

Answer 6

inlet manifold

Question 7

zerstaeubt

Answer 7

atomised

Question 8

1/4 engine sequence

Answer 8

SUCK / INTAKE
the inlet valve opens
air is drawn in through the air filter
through the inlet manifold into the chamber
by the vacuum created from the cylinder

Question 9

drawn

Answer 9

gezogen

Question 10

2/4 engine sequence

Answer 10

SQUEEZE / COMPRESSION
at the bottom of the cylinder stroke the inlet valve close,
preventing air escaping back up the inlet manifold, as the cylinder rises as part of its upward stroke

Question 11

Zylinderhub

Answer 11

cylinder stroke

Question 12

3/4 engine sequence

Answer 12

BANG / POWER
the pistons compresses the air heating enough to ignite the atomised fuel injected by the injector into the cylinder
the ignited fuel-air mixture forces the piston back down the cylinder chamber and in turn, rotating the crank shaft

Question 13

4/4 engine sequence

Answer 13

BLOW / EXHAUST
once at the bottom of the stroke, the exhaust valve opens and the rising cylinder forces the exhaust gasses out of the chamber.
Once at the top of the cylinder, the exhaust valve closes, the inlet valve opens and the process starts again.

Question 14

how much air in relation to the fuel?

Answer 14

14.5 times that of diesel by weight

Question 15

the 4 strokes of a diesel engine:

Answer 15

Intake – The piston moves down, and air enters the cylinder.

Compression – The piston moves up, squeezing the air and making it very hot.

Power – Fuel is injected, ignites from the heat, and pushes the piston down.

Exhaust – The piston moves up again, pushing out the burned gases.

Question 16

WOBBLE

Answer 16

Water: Check the raw water seacock is turned on. Check the coolant water level and top up if necessary.

Oil: Check the oil levels and top up if necessary.

Belt: Check any belts, such as the alternator drive belt, for tension and wear.

Bilges. Check the bilges for water, oil and black dust which could have come from a worn fan belt.

Leaks: Check all pipe connections, water pump and stern gland/s for leaks especially if there is excess water in the bilges.

Exhaust: Once the engine has started, check that water is being ejected from the exhaust.

Question 17

key areas to check before starting a engine

Answer 17

cooling system,
fuel system,
lubrication,
air system,
engine electrics,
engine driven bilge pump

Question 18

3 main causes of fire?

Answer 18

galley
marine engine
electrical

Question 19

Answer 19

Strainer

Question 20

elements of the seawater cooling system

Answer 20

seacock
strainer
fresh seawater pump
syphon breaker
heat exchanger
exhaust injection

Question 21

die Dichtung

Answer 21

gasket

Question 22

A creamy substance in the oil indicates …

Answer 22

… that water is mixing with it possibly due to a leaking cylinder head gasket. Have the engine looked at by a qualified diesel mechanic.

Question 23

An increase in oil levels indicates …

Answer 23

…diesel is getting into the oil, usually due to faulty injectors. These can be removed and serviced.

Question 24

Gritty oil indicates …

Answer 24

…possible wear (Abnutzung) inside the engine. The engine should be flushed out, the oil replaced and the engine and oil monitored to see if the problem reoccurs.

Question 25

Very black oil with little viscosity means...

Answer 25

...the engine needs an oil change and oil filter change.

Question 26

Black smoke can indicate ...

Answer 26

... the engine is labouring due to a rope round the prop, dirty hull, blocked engine air filter, faulty injectors or a faulty injection pump.

Question 27

Blue smoke indicates ...

Answer 27

...the engine is burning oil. This can be due to a faulty turbo or an internal problem with the engine.

Question 28

What are you doing with a Dipstick?

Answer 28

oil level check

Question 29

The most common causes for the alternator not delivering power are:

Answer 29

Slipping or broken drive belt. Loose connections at the alternator, battery or anywhere else in the charging circuit. Faulty battery

Question 30

If the starter battery is fully charged and you cannot hear the 'clunk' when attempting to start the engine, there are four common potential issues.

Answer 30

The starter motor is jammed. Try tapping the starter motor housing with a hammer using moderate force. The solenoid is not operating due to being jammed. Try tapping the solenoid with a hammer with light force. The solenoid energising circuit is not operating. Check the fuse. The power circuit is not connected. Check all battery isolation points, cabling, and the starter motor fuse if fitted.

Question 31

What is a Glow Plug?

Answer 31

a glow plug is used to apply heat to the engine to support starting.

Question 32

abgenutzt

Answer 32

worn

Question 33

Check the area around and below the alternator for signs of black dust, which would indicate...

Answer 33

... that the belt is worn and may need to be replaced.

Question 34

Turbos allow a smaller engine to create the power equivalent to a much larger engine but there are some limitations:

Answer 34

The turbo does not provide additional power at low engine revolutions. They put the engine under a lot more stress and wear. There is a significant increase in heat generated within the engine bay, with a hotter exhaust system so specialised exhaust systems are needed to handle the increase in temperature. They add to the complexity of the engine, so are harder to fix when out on the water. Significantly more expensive to purchase. Much higher maintenance costs.

Question 35

Turbo charging provides ...

Answer 35

...an increase in power by supplying air at a positive pressure to the combustion chamber allowing a greater air-fuel mixture and creating more power.

Question 36

A wastegate...

Answer 36

...allows the excess exhaust gasses to bypass the turbo.

Question 37

Blue smoke from the exhaust can be an indication that ...

Answer 37

... the turbo may have an oil leak.

Question 38

A intercooler...

Answer 38

...cool the compressed inlet air before it enters the engine

Question 39

What are Turbos for?

Answer 39

Turbos are a very effective way to increase engine power for a given size and allows engines to be installed in a vessel that are smaller and lighter than a normally aspirated version of the same size.

Question 40

die Magnetspule

Answer 40

solenoid

Question 41

syphon breaker ...

Answer 41

bleed the air from the cooling system

Question 42

Black or grey smoke indicates...

Answer 42

poor combustion

Question 43

Black or grey smoke, 7 causes:

Answer 43

- Excessive marine growth on the propeller - Excessively dirty hull - Dirty fuel - Fouled injectors or injector pump - Fouled air filter - Turbocharger seal failure - Fire in the engine compartment

Question 44

Blue smoke indicates...

Answer 44

... oil is burnt in the combustion chamber.

Question 45

Blue smoke, 4 causes:

Answer 45

- Incorrect oil grade - Diesel fuel in the oil - Excess pressure in the crankcase - Turbo oil seal

Question 46

das Motorgehaeuse

Answer 46

crankcase

Question 47

die Dichtung

Answer 47

seal

Question 48

White smoke occurs ...

Answer 48

... when unburnt diesel enters the exhaust.

Question 49

White smoke, check...

Answer 49

The condition of the fuel. The condition of the fuel filters.

Question 50

Abwuergen

Answer 50

to stall

Question 51

A diesel engine needs three things to operate:

Answer 51

fuel, air, and compression

Question 52

Fault-finding - Engine Stalls (5)

Answer 52

- wrapped a rope around the propeller! - Lack of fuel - Contaminated fuel - Blocked or damaged hoses - Blocked fuel tank vent