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EGK Engines > Lubrication And Cooling > Flashcards

Lubrication And Cooling Flashcards

1
Q

Functions Of Oil

A

Lubricate
Clean
Reduce wear
Seals
Protection from corrosion
Cooling

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2
Q

Required Oil Properties

A

Optimal Viscosity - high enough for lubricate but low enough to flow

High flash point - temperature at which oil gives off vapours

Low carbon forming tendencies

Discourage of sludge

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3
Q

Oil Grades (Saybolt)

A

Graded according to viscosity

Higher the temp the higher the grade

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4
Q

Wet Sump System

A

All of the oil carried in a sump within crankcase
Drawn from sump via suction filter
Requires greater quantity of oil to have supply

Utilises a gravity return system
High oil temp means viscosity is too low and lubricating layer too this

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5
Q

Dry Sump Tank

A

Oil held in a tank mounted remotely from engine

Pump provides more oil pressure than necessary - pressure can be guaranteed

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6
Q

Relief Valve in Dry Sump

A

Located after the OPP and functions to return oil to pump inlet if pressure too high

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7
Q

Disadvantages of wet sump

A

Limited amount of oil
Higher oil temps and shorter oil life
Not suited for radial and aerobatic a/c
+simple and cheap though

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8
Q

Dry Sump (4 pumps)

A

Oil pressure pump - draws oil from sump

Oil scavenge pump - in supply line
- capacity is OPP x 3
- supply oil has larger volume as mixes with air

Governor pump - engine lubricating oil used to change pitch of CSP

Feathering pump - electrically driven
Used to feather prop when engine fails

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9
Q

Oil Filter

A

Between Oil Pressure Pump and engine
Removes contaminants
Bypass valve required to ensure continuous flow if blocked

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10
Q

Suction Filter

A

High pressure filter to various placed jets to lubricate points and bearings

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11
Q

Dry Sump - Big end bearings pressure and light loaded components pressure

A

Big end bearings Fed with high pressure oil at 4 to 5 bars (60/70psi)

Fed with low pressure oil via pressure reducing valve (oil to camshaft)

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12
Q

Dry Sump Scavenge Pump

A

Pumps oil back to oil tank via oil cooler
More powerful than high pressure pump to ensure oil does not pool in sump

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13
Q

Oil Tank

A

Reserve of oil to allow for fluctuations in demand/thermal expansion/minor leaks

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14
Q

De-aerator plate - Dry Sump role

A

On oils return from engine/separate out air bubbles suspended in the oil

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15
Q

Hot Well - Dry sump role

A

On start when oil is cold and viscous oil drawn from hot well.

Refills with hot oil returning from engine so establishes a good circulation.

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16
Q

Coarse Filter - Dry Sump System

A

Cleans oil by trapping dirt/metals carried by oil

17
Q

Magnetic Plugs - Dry Sump

A

Used for engine condition monitoring

18
Q

Oil Pump

A

Engine driven/speed varies with engine RPM
Pump output increases at higher engine speed
Regulated by pressure relief valve

Low oil pressure at high RPM indicate worn oil pressure pump

19
Q

Oil Cooler - Dry Sump/wet sump

A

Dry Sump - Fitted in return line between scavenge pump and oil tank

Wet Sump - Oil cooler fitted in pressure supply line

20
Q

Anti surge valve - dry sump

A

Allows oil to bypass the cooler when it is cold and viscous
Doesn’t need to be cooled

21
Q

Oil Temp Gauge - Dry Sump

A

Measures temp of oil in supply line after the cooler before the pressure pump

22
Q

Oil Pressure Gauge

A

Measures oil pressure at outlet of pressure pump

Cold oil = more viscous = higher pressure reading
Warm oil = less viscous - lower pressure reading

Indicate within 30 secs of starting

23
Q

Splash Lubrication

A

Spray oil onto moving parts across the crankshaft

24
Q

Wet vs Dry Sump

A

Wet Positives/Negatives
+ Cheaper/Easier
+ Less parts
- inversion could lead to oil starvation
- greater quantity of oil needed to supply oil pump
- risk of excessive oil at high RPM
- not filtered or cooled

Dry Sump Positives/Negatives
+ oil contained separately
+ Filtered and cooled under all flight conditions
- more moving parts

25
Q

Checking Oil Lvls Dry vs Wet

A

Dry check straight after shut down (start to drain back into engine)

Wet check 20 minutes to allow time for all to drain back to sump

26
Q

Oil Consumption - What causes it?

A

Oil leaking past piston rings into cylinder then combusts with mixture and expelled from exhaust

Worn piston rings = greater consumption
Low viscosity = more escapes past oil control ring

27
Q

Liquid Cooling System

A

Water + glycol through galleries in crank case and cylinder

Hot fluid piped to radiators using ram air to cool and then returning to engine

Thermostat valve controls engine temperature in cooled system

28
Q

Air cooling systems

A

Air inlet directs air over engine via baffles (control flow)
Cowl flap open to increase cooling flow
Exhausted hot gas to atmosphere

29
Q

Cylinder Head Temperature

A

Measures temp of cylinder usually the hottest on closet at is the hottest

Measured via thermocouple requires no electrical supply

30
Q

Saybolt System to SAE No

A

SAE no will be around half of the Saybolt number

31
Q

Oil Coring

A

Excessive cooling leading to congealed oil blocking system
Oil temp excessive and cooler flap open suspect coring
Close the cooler flap

32
Q

Cowl Flaps

A

Regulate the flow of cooling air to the engine
Open at full power on a climb and close for a low power descent

33
Q

Thermostat Valve

A

Controls engine temperature in liquid cooled system

34
Q

Detonation causes

A

Low RPM with a high power setting

35
Q

Hot well (Hot Pot)

A

Reduce time taken to raise the temperature of the oil when starting the engine from cold restrict quantity of oil in circulation

36
Q

Anti Surge Valve

A

Fitted to bypass matrix on start when oil is cold and thick

37
Q

Oil returning to oil tank is filtered by

A

Scavenge filter

38
Q

Purpose of magnetic chip detectors

A

To find ferrous metallic particles in the oil to detect impending engine failure

EGK Engines (22 decks)

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