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Engine Lubricants and
Lubricating Systems
Home Page: http://baen.tamu.edu/users/lepori/
AGSM 201 Slides Page:<http://baen.tamu.edu/users/lepori/agsm_power_point_slides.htm>
Functions of Engine Oils
1. Reduce wear
2. Reduce friction
3. Seal Compression
4. Reduce noise
5. Cool engine parts
6. Reduce rust
7. Keep parts clean
Organizations Providing Uniform Standards for Oil S.A.E.
Society of Automotive Engineers A.P.I.
American Petroleum Institute A.S.T.M.
American Society of Testing & Materials American Automobile Manufacturers
Association Engine Manufacturers Association I.S.O.
International Standards Organizations
Properties of Motor Oils
ViscosityViscosity Index (VI)Flash PointPour PointPer cent sulfated ashPer cent zinc.
Properties of Motor Oils
ViscosityViscosity Index (VI)Flash PointPour PointPer cent sulfated ashPer cent zinc.
Viscosity Measure of the "flowability“
Kinematic Dynamic
Property – Resistance to flow Shearing stress
High viscosity - thick oils Too high viscosity may not reach all parts
Low viscosity – thin oil Too low viscosity may not provide enough strength to
keep parts from wearing
Dynamic & KinematicViscosity
Kinematic Viscosity Measurement
Saybolt Viscometer Glass capillary viscometers
Dynamic Viscosity Measurement
Typical Brookfield Viscometer
Weight of oils Common term identifying viscosity for oils Numbers assigned by the S.A.E.
correspond to "real" viscosity, as measured by accepted techniques.
These measurements are taken at specific temperatures.
Oils that fall into a certain range are designated 5, 10, 20, 30, 40, 50 by the S.A.E.
The W means the oil meets specifications for viscosity at 0 F and is therefore suitable for Winter use.
_______________________________________________________________
| |
| SAE Gear Viscosity Number |
| ________________________________________________________ |
| |75W |80W |85W| 90 | 140 | |
| |____|_____|___|______________|________________________| |
|
| SAE Crank Case Viscosity Number |
| ____________________________ |
| |10| 20 | 30 | 40 | 50 | |
| |__|_____|____|_____|______| |
______________________________________________________________
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42
viscosity cSt @ 100 degrees C
Properties of Motor Oils
ViscosityViscosity Index (VI)Flash PointPour PointPer cent sulfated ashPer cent zinc.
Viscosity index The measure of an oil's ability to resist
changes in viscosity when subjected to changes in temperature.
As temperature increases
viscosity decreases. Low temperatures –
High viscosity High temperature –
Low viscosity
Multi-viscosity/Multi-grade Oil Oil meeting SAE requirements for
both low-temperature requirements of light oil and high-temperature requirements. Also know as multiweight oil.
Oil that meets certain low-temperature and high-temperature requirements simultaneously
(e.g., SAE l0W-40).
Properties of Motor Oils
Viscosity Viscosity Index (VI)
Flash Point Minimum sample temperature at which vapor is
produced at a sufficient rate to yield a combustible mixture.
Pour Point The lowest temperature at which oil will pour.
Per cent sulfated ash Per cent zinc.
Properties of Motor Oils
Viscosity Viscosity Index (VI) Flash Point Pour Point
Percent sulfated ash how much solid material is left when the oil burns. A high ash content will tend to form more sludge
and deposits in the engine. Low ash content also seems to promote long valve
life. Look for oils with a low ash content. Per cent zinc.
Properties of Motor Oils Viscosity Viscosity Index (VI) Flash Point Pour Point Per cent sulfated ash
Percent zinc the amount of zinc used as an extreme pressure,
anti-wear additive. The zinc is only used when there is actual metal to
metal contact in the engine. Hopefully the oil will do its job and this will rarely occur, but if it does, the zinc compounds react with the metal to prevent scuffing and wear.
A level of 0.11% is enough to protect an automobile engine for the extended oil drain interval, under normal use.
Common motor oil additivesViscosity index improvers
used to enhance the base qualities of the oil, and to keep the oil from thinning too much as heat increases.
Pour-point depressants prevent crystals from forming in extreme
cold conditions, and consequently lower the oil's pour point (temperature at which it pours).
Common motor oil additivesOxidation inhibitors
help prevent the oil from oxidizing (in other words, burning). When oil oxidizes, it loses its ability to protect the engine. It also produces sludge deposits and traps corrosive acids.
Rust-corrosion inhibitors help prevent and neutralize water and
oxygen from acid-etching the metals in the engine and forming rust particles. If this corrosion were to happen, some complex acids would form and other sludge problems would occur.
Common motor oil additivesDispersants
help the oil to absorb and retain contaminants such as dirt or tiny metal particles (from engine wear) until the oil passes through the oil filter, where the contaminants are trapped.
Detergents help to remove contaminants from the engine
components and hold them in the oil until it reaches a filter, or until it is changed the next time. They don't only clean up a dirty engine.
Common motor oil additivesFriction modifiers/wear inhibitors
"stick" to engine surfaces better, reducing friction and improving fuel economy. Oils with the "energy conserving" labels contain friction modifiers.
Foam inhibitors (Antifoamants) prevent the oil from being whipped into many
tiny air bubbles. Air bubbles don't lubricate. This also helps prevent sludge formation when the emulsion process is a possible threat in an engine.
Types of Motor Oils Petroleum Based
Refined from crude oil Supplemented with additives
Synthetic Lubricants chemically engineered from pure chemicals
rather than refined from crude oil. Can provide significant advantages over refined oils.
Longer oil change intervals Longer engine life Increase gas mileage
More expensive
What the h___ is he talking about?
Items that tell us about selecting an oil!
What the h___ is he talking about?
How to select an oil for different purposes.
What to look for on an oil container.
What Oil Should You Use
API “Donut”
GasolineServiceClassification
DieselEngineClassification
Lubrication SystemsSplash
Dipper Slinger
Force Feed & SplashFull Force Feed
Splash Lubrication
Force Feed and Splash
Full Force Feed
Oil Pump
Oil pump intake screen
Engine Oil Degradation and Contamination Oil thickening
Oxidation Vaporization of lighter
components Fuel
Hydrocarbon compounds Combustion Products
Carbon Water Sulphur Oxides Fuel chemical additives
Dust and Dirt Metal – from wear of
components
Oil Filtration Systems
By-PassFull –FlowShunt
Engine Lubrication System with both by-pass and full-flow filtration
Two filters provide ability to filter smaller particles
Filter elements Surface
Pleated paper Metal screen
Depth Cotton waste
Changing oil and filters renews engine protection Dirty oil reduces life of an engine. Reduce maintenance and increase engine life
by changing engine oil and filters on a regularly scheduled basis.
Interval between changes depends on operating conditions.
Oil analysis provides management of oil change intervals Recommend for fleet operations.
Oil Pressure – Important Sensor
Low pressure light indicator
Lubrication Links on the Web Motor oils and more Motor Oil Functions & Properties Selecting motor oils
API Starburst and Donut Motor Oil Additives Lubrication Systems Filtration Systems
Sources of oil contaminants Filters & filter media
Synthetic oil base stocks Synthetic oil history Oil Analysis –
Example 1 Example 2
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