lubrication Flashcards
what is the main purpose of lubrication?
to reduce frictional wear and tear between parts with a layer of lubrication called a “film”
what is viscosity
a measure of how much resistance to flow a lubrication has (thickness)
what is Viscosity Index (V.I)
a rating system used to determine changes in viscosity with temperature
low viscosity index indicates that a lubricant has?
high change in viscosity with temperature
high viscosity index indicates what in a lubricant?
little to no change with temperature
what is flash point?
the temperature which a lubricating oil gives off flammable fumes
what are two types of oils?
detergent oils and dispersant oils
what are additives?
are substancrs added to oils which improves its quality
what are two main classes of additives
class 1 and class 2
what are two types of lubrication and define them?
boundary lubrication- partial separation of surfaces by a lubricant (eg splash lubrication)
fluid lubrication- complete separation of surfaces by a lubricant (eg between bearings)
what are dispersant oils ?
oils which help remove impurities from the engine over different ranges of speeds and loads
list 3 Class 1 additives
- VI enhancers
- anti foam agents
- pour point depressants
list 5 class 2 additives.
oxidation inhibitors
detergent dispersants
film strength additive
extreme pressure additives
multiple grade oils
what are detergent oils?
oils designed to cope with severe engine conditions and reduce sludge formations, etching and varnish buildup
what are the 4 main effects of a lubricant regarding the automotive industry
friction and wear reduction
sealing effect
cushioning effect
cooling effect
