Oil Systems Flashcards
What does lubrication eliminate
Friction
Wear
What does lubrication also help with
Cooling
What are the two phases of lubrication
Film
Boundary
General points in engine lubrication
Oil used needs to be quick flowing and of low viscosity
What is used to remove heat from the engine
Oil and air
What does oil need to withstand
High pressures
High temperatures
What type of oil can withstand High temperatures
Synthetic oil OX
What system is this ?
May have a separate oil tank
Dry sump system
What system is this
The oil may be contained in the sump
A wet sump system
What bearings support the turbine and compressor
Roller bearings - radial and axial loads
Ball bearings - axial and thrust loads
Squeeze film - minimise vibration
What do speciap bearings (squeeze film) do
Minimise vibrations
What do seals do
Prevent oil migrating to areas where it should not be
What types of seals are there
Carbon
Brush
Lip
Labyrinth
What seals rely on physical contact with the rotating assembly
Carbon
Brush
Lip
What are labyrinth seals used for
Internal sealing preventing escape of oil from bearing surface
What does the labyrinth seals use to actually function other than oil
Air
What are the two main methods of lubrication
Oil mist - atomized
Oil jet - directed
Purpose of an oil system
Provide storage facilities for oil
Deliver oil to various parts at suitable rate
Effiecent lubrication and cooling
Types of oil system two
Recirculatory system - oil is distributed and returned to the oil tank by pumps
Expendable system
Two types of recirculatory system
PRV System
Full flow system ( this one is better )
PRV recirculatory system (pic)
Full flow system (pic)
Full flow system adv 3
Provides a suitable flow
A suitable pressure
At all engine speeds
Typical oil system PRV type parts ( pic )
Two ways of removing air from oil
Baffles
Centrifugal breather
Describe how the centrifugal breather works
Rotating component, separates oil from air. Oil drains back down the tank and air leaves through tanks
Oil system maintenance 8 (pic)
Health and safety 7 (pic)
