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ATPL - [Mod 2] AGK - Engines > 06. Piston Engine Lubrication and Cooling > Flashcards

06. Piston Engine Lubrication and Cooling Flashcards

1
Q

The primary function of oil in an engine is to reduce
____ and ____

A
  1. Friction
  2. Wear

Pg 141

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2
Q

The 4 secondary functions of engine oil are

A
  1. Cooling
  2. Cleaning
  3. Protection
  4. Hydraulic

Pg 141

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3
Q

Which 2 readings values can be monitored to determine the condition of an engine

A
  1. TEMPERATURE - Oil temperature
  2. PRESSURE - Oil pressure

Pg 141

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4
Q

What is viscosity

A

RESISTANCE OF FLUID to FLOW

Pg 142

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5
Q

High viscosity oil makes the engine MORE or LESS difficult to turn over

A

MORE

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6
Q

Low viscosity oil makes the engine MORE or LESS difficult to turn over

A

LESS

Pg 142

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7
Q

What is the primary benefit of a high viscosity oil

A

GUARANTEES GOOD FILM

Guarantees a good film on the bearings

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8
Q

The higher the oil number, the HIGHER or LOWER the viscosity

A

HIGHER

HIGHER = HIGHER, lower = Lower

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9
Q

What are 5 properties aero engine oil must achieve

Sticky Sludge Corrodes Materials and then Evaporates

A
  1. Sticky - VISCOSITY - Maintain viscosity over a wider range of temperatures and pressures
  2. Sludge - SLUDGE - Discourage sludge formation
  3. Corrodes - CORROSION - Inhibit corrosion
  4. Materials - MATERIALS - Not react with materials
  5. Evaporates - EVAPORATION - Low evaporation point

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10
Q

Compound oil is oil containing what

A

ADDITIVES

Pg 142

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11
Q

Oil containing additives is known as what

A

COMPOUND OIL

Pg 142

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12
Q

Oil used in new engines to reduce running-in time is known as what

A

STRAIGHT OIL

Pg 142

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13
Q

Straight oil is used specifically for what, and has NO or ADDITIONAL additives

A
  1. RUNNING IN new engines
  2. NO ADDITIVES

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14
Q

What should an aircraft operator do with oil according to the engine manufactorer

A

CHANGE THE OIL

Change oil according to the schedule

Pg 143

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15
Q

Blue or grey smoke in the exhaust is a sign of what

A

EXCESSIVE OIL BURNING

Pg 143

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16
Q

Excessive oil burning is identified by smoke of what 2 colours in the exhaust

A
  1. BLUE
  2. GREY

Pg 143

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17
Q

What are the 2 methods of storing engine oil

A
  1. DRY sump
  2. WET sump

Pg 144

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18
Q

Oil held in a tank mounted remotely from the engine is a ____ sump system

A

DRY

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19
Q

Oil held in the bottom of the crankcase is a ____ sump system

A

WET

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20
Q

Dry Sump System

Name the components of the dry sump oil system
LINK HERE

A

ANSWERS HERE

Pg 145

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21
Q

Dry Sump System

In a dry sump system, how is oil drawn into the engine

A

ENGINE DRIVEN PUMP
(EDP)

Pg 145

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22
Q

Dry Sump System

What is the purpose of a Pressure Relief Valve

A

REGULATES SYSTEM PRESSURE

Pump provides more oil pressure than necessary.
Ensures that sufficient pressure available under extreme conditions

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23
Q

Dry Sump System

Highly loaded points such as big end bearings that require high pressure are provided oil at around ____ to ____ PSI

A

60 - 70 PSI

4 - 5 bar

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24
Q

Dry Sump System

The camshaft is fed by HIGH or LOW pressure oil

A

LOW

Via a pressure-reducing valve

Pg 146

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25
Q

Dry Sump System

What is the purpose of a scavenge pump

A

PUMP OIL to OIL TANK

Via the oil cooler

Pg 146

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26
Q

Dry Sump System

How is oil pumped back to the oil tank

A

SCAVENGE PUMP

Pg 146

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27
Q

Dry Sump System

Oil returns from the engine via the ____ line and ____ valve

A
  1. Scavenge line / Oil return line
  2. Non-return (check) valve

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28
Q

Dry Sump System

What is the purpose of the de-aerator plate

A

SEPARATE OUT AIR BUBBLES

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29
Q

Dry Sump System

What component is used to seperate out air bubbles from fuel returning to the tank

A

DE-AERATOR PLATE

Pg 147

30
Q

Dry Sump System

What is used in the tank to prevent fluid from sloshing around

A

BAFFLES

Pg 147

31
Q

Dry Sump System

What is the purpose of a hot well

A

HOT OIL RETURN on startup

On startup, oil is viscious. Oil is pulled in to the engine first from the hot well.
As the oil returns to the tank, it has been warmed by the engine and drops into the hot well
This ensures that warmer oil is returned back to the engine whilst the surrounding oil in the tank is gradually heated to temperature

Pg 147

32
Q

Dry Sump System

The coarse filter fitted before the pressure pump is know as a SUCTION or SCAVENGE filter.
The coarse filter fitted before the scavenge pump is known as a SUCTION or SCAVENGE filter.

A
  1. SUCTION
  2. SCAVENGE

Pg 147

33
Q

Dry Sump System

What component is used to remove ferrous particles from the oil in the return line

A

MAGNETIC PLUGS

Chip Detectors

Ferrous particles from the engine or gearbox are caught by magnets

Pg 148

34
Q

Dry Sump System

Oil pumps are driven by the ____ and normally through the use of ____ (mechanical component).
The pump speed varies with ____

A
  1. Engine
  2. Spur gears
  3. Engine RPM

Pg 148

35
Q

With higher RPM speeds, how is pump pressure regulated

A

PRESSURE RELIEF VALVE

Pg 148

36
Q

Dry Sump System

With high RPM speeds, a low oil pressure may indicate what

A

WORN OIL PRESSURE PUMP

Pg 148

37
Q

Dry Sump System

How does the PRV operate when there is excessive pressure detected from the EDP.

A

SPRING LOADED VALVE

Spring loaded valve opens which allows oil to be moved back to the suction side of the pump

Pg 148

38
Q

Dry Sump System

What component is fitted to ensure that oil continues to lubricate the engine if the pressure filter becomes blocked or clogged

A

BY-PASS VALVE

Pg 148

39
Q

Dry Sump System

Between which 2 system components is the oil cooler fitted

A

SCAVENGE PUMP (& magnetic chip detector) < > OIL TANK

Fitted in the scavenge line

Pg 149

40
Q

Dry Sump System

What is the purpose of an anti surge valve

A

BY-PASS AIR COOLER

Allows oil to bypass the cooler when cold and viscious

Pg 149

41
Q

Dry Sump System

The Oil temperature gauge measures the oil temperature after the ____ and before the ____

A
  1. Oil cooler (& oil tank / hot well)
  2. Pressure pump

Pg 151

42
Q

Dry Sump System

The oil pressure gauge measures oil pressure at which point in the system

A

OUTLET of the PRESSURE PUMP

Pg 151

43
Q

Dry Sump System

Oil pressure and temperature are inextricably linked.
For a given RPM, cold oil will indicate a HIGER or LOWER pressure than oil operating at a normal temperature

A

HIGHER

Pg 151

44
Q

Wet Sump System

What is the core difference between a wet sump and a dry sump system

A

OIL TANK vs OIL SUMP

Dry sump system uses an oil tank to collect and hold oil
Wet sump system collects oil in the engine sump

Pg 153

45
Q

Wet Sump System

What is an inherent risk of a wet sump system

A

INVERTED FLIGHT
(oil starvation)

Oil disperses around engine during inverted flight

Oil disperses around the system during inverted flight.
This can quickly lead to oil starvation

Pg 153

46
Q

Wet Sump System

What is the name given to the method of lubrication in whcih in the crankshaft cycles through the oil in the sump

A

SPLASH LUBRICATION

Pg 152

47
Q

Wet Sump System

What are 2 disadvantages of a wet sump system in regards to high RPM and splash lubrication

A
  1. EXCESSIVE OIL - High RPM can cause excessive oiling
  2. NOT COOLED or FILTERED

Pg 153

48
Q

After shutdown, when should the oil level be checked in;
1. Dry Sump System
2. Wet Sump System

A
  1. IMMEDIATELY
  2. 20 Mins

Pg 153

49
Q

Worn piston rings and worn piston heads will result in FASTER or SLOWER oil consumption

A

FASTER

Worn rings and worn piston head allows oil to get past the piston skirt, leading to greater oil consumption

Pg 154

50
Q

Low viscosity oil will lead to GREATER or LOWER oil consumption

A

GREATER

Low viscosity oil can eascape past the oil control ring on the piston

Pg 154

51
Q

When should the oil level in the reservoir be checked

A

BEFORE EVERY FLIGHT

Pg 154

52
Q

What will lead to an increase in oil temperature and a decrease in oil pressure

A

LOW OIL QUANTITY

Low oil quantity means less oil in the system.
This means it passes back through the system more quickly, having less time to be cooled, subsequnetly increasing in temperature and lowering the pressure

Pg 154

53
Q

Generally, a decrease in oil temperature will lead to a DECREASE or INCREASE in oil pressure

A

INCREASE

Colder oil means more viscious. If more viscious, it does not pass through the system as easily.
Oil moving less freely will build system pressure

Pg 154

54
Q

What are 2 methods of cooling piston engines

A
  1. AIR
  2. LIQUID

Pg 156

55
Q

Liquid Cooled System

What is a benefit and a disadvantage

A
  1. LESS DRAG - Benefit
  2. INCREASED WEIGHT - Disadvantage

Less drag as there are no air intakes required
Increased weight due to the extra liquid required

Pg 156

56
Q

Liquid Cooled System

How does the liquid diserpate heat back to the atmosphere

A

RADIATORS and RAM AIR

Hot fluid is piped through radiators which use ram air to cool the fluid

Pg 157

57
Q

Air cooled system

What are 2 advantages

A
  1. Reduced weight
  2. Less moving parts

Pg 158

58
Q

Air cooled system

What component is used to increase the external surface area

A

DEEP FINS

Pg 158

59
Q

Air cooled system

What is the purpose of cylinder baffles

A

CONTROL FLOW OF AIR

Ensures each cylinder evenly cooled

Pg 158

60
Q

Air cooled system

What component is used to control the flow of air to ensure each cylinder is evenly cooled

A

CYLINDER BAFFLES

Pg 158

61
Q

Temperature measurement

Where does the highest temperature occur in an engine

A

CYLINDER HEAD

Pg 159

62
Q

Temperature measurement

What does CHT stand for

A

CYLINDER HEAD TEMPERATURE

Pg 159

63
Q

Temperature measurement

How is the CHT measured

A

THERMOCOUPLE

Pg 159

64
Q

Temperature measurement

What 4 things affect the temperature a cylinder head opeartes at during normal operation

P A M S

More cylinders gives Power And More Speed

A
  1. POWER
  2. AIR
  3. MIXTURE
  4. SPEED

  1. POWER - Amount of power being produced
  2. AIR - Temperature of cooling air
  3. MIXTURE - Mixture ratio
  4. SPEED - Mass flow of cooling air - aircrafts forward speed

Pg 159

65
Q

Temperature measurement

What type of mixture will cause an increase in CHT

A

LEAN MIXTURE
(weak)

Less mixture means less cooling of the cylinder head
Weak mixture burns more slowly which gives more time to heat components

Pg 160

66
Q

Temperature measurement

What conditions are most likely to cause engine overheat

A

low speed, HIGH POWER

Example: Extended climb

Low speed means less air flow entering the engine to assist with cooling
High power means the engine is working hard and hot

Pg 160

67
Q

Temperature measurement

What condictions are most likely to cause engine over cooling

A

HIGH SPEED, low power

Example: High speed descent with idle power

High speed means excessive air is entering the engine to assist with cooling
Low power means the engine is hardly working and is cooling down in the process

Pg 160

68
Q

Temperature measurement

What is a risk of over cooling an engine

A

THERMAL SHOCK

Pg 160

69
Q

Temperature measurement

What are fitted on some engines to assist with regulating the flow of cooling air

A

COWL FLAPS

Pg 160

70
Q

Temperature measurement

Cowl flaps are OPENED or CLOSED for full power climb, and OPENED or CLOSED for low power descent

A
  1. OPENED
  2. CLOSED

Power on climb means engine is working hard and slow airflow, so more air is needd to assist in cooling
Low power and fast descent means more air may result in thermal shock. Less air is required to flow over the engine

Pg 160

ATPL - [Mod 2] AGK - Engines (23 decks)

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