Engine TerminologyEngine Terminology

Engine Lubrication PrinciplesEngine Lubrication Principles

Engine OilsEngine Oils

Lesson 1Lesson 1

Engine Doc – S. Ruch 2008Engine Doc – S. Ruch 2008

Agenda

• Primary function• Lubrication principles• Hydrodynamic action• Engine oils• Ratings

Primary Function

• Separate moving components

Lubrication PrinciplesLubrication Principles

Hydrodynamic LubricationHydrodynamic Lubrication

HydroHydro - liquids - as in hydraulics - engine oil - liquids - as in hydraulics - engine oil

DynamicDynamic - motion - engine parts in relative motion - motion - engine parts in relative motion

Hydrodynamic LubricationHydrodynamic Lubrication • is the wedge shape of oil film that completely is the wedge shape of oil film that completely

separates two surfaces that have relative separates two surfaces that have relative motionmotion

Do you remember the name for engine Do you remember the name for engine bearings?bearings?

Anti-Friction Bearings

Hydrodynamic LubricationHydrodynamic Lubrication • occurs between the shaft journals and the occurs between the shaft journals and the

bearing inserts.bearing inserts.

YouTube - SPH BEARING FLOW

Hydrodynamic LubricationHydrodynamic Lubrication

• The engine lubrication system must provide a constant The engine lubrication system must provide a constant supply of clean oil at a high enough pressures to force oil supply of clean oil at a high enough pressures to force oil to the bearings to allow enough flow for cooling of the to the bearings to allow enough flow for cooling of the bearing surfacesbearing surfaces

• The oil is supplied to the lightly loaded area of the bearing The oil is supplied to the lightly loaded area of the bearing and then the hydrodynamic process takes overand then the hydrodynamic process takes over

• The hydrodynamic oil film pressures developed on the The hydrodynamic oil film pressures developed on the engine bearing surfaces may exceed 1000 psi.engine bearing surfaces may exceed 1000 psi.

• Loss of oil supply will result in bearing failureLoss of oil supply will result in bearing failure

Hydrodynamic LubricationHydrodynamic Lubrication

• NormalNormal bearing wear happens when there is a lack of bearing wear happens when there is a lack of hydrodynamic lubrication. hydrodynamic lubrication.

• This occurs when?This occurs when?

Initial engine start upInitial engine start up

• When the engine is off, the crankshaft pushes most of the When the engine is off, the crankshaft pushes most of the oil from around it as it settles to the bottom of the bearings. oil from around it as it settles to the bottom of the bearings.

Boundary LubricationBoundary Lubrication

• Occurs when the oil film is extremely thin and Occurs when the oil film is extremely thin and the high spots of the surfaces touchthe high spots of the surfaces touch

Engine OilsEngine Oils

PurposePurpose• Lubricate all moving parts to prevent wearLubricate all moving parts to prevent wear• Reduce frictionReduce friction• Aid in cooling the engineAid in cooling the engine• Assist the cylinder seal at the piston ringsAssist the cylinder seal at the piston rings• Neutralize acids formed from combustion Neutralize acids formed from combustion

processprocess• Prevent rust and corrosionPrevent rust and corrosion• Clean the engine and hold dirt in suspensionClean the engine and hold dirt in suspension

Oil ViscosityOil Viscosity• Viscosity is the resistance to flow of an oil Viscosity is the resistance to flow of an oil

• A high viscosity oil has a greater resistance to A high viscosity oil has a greater resistance to flow and is said to be thicker than a lower flow and is said to be thicker than a lower viscosity oil viscosity oil

• As an oil cools it thickens and as it heats up it As an oil cools it thickens and as it heats up it thins out.thins out.

• Viscosity changes with temperatureViscosity changes with temperature

Oil ViscosityOil Viscosity• Oil must not be too thick at low temperatures or cranking Oil must not be too thick at low temperatures or cranking

speeds will be low, and hard or no starts will result, due to speeds will be low, and hard or no starts will result, due to the increased co-efficient of friction.the increased co-efficient of friction.

• Oil must not be too thin at high temperatures or the oil Oil must not be too thin at high temperatures or the oil film will not support the loads placed on it and boundary film will not support the loads placed on it and boundary lubrication will occur and increase the co-efficient of lubrication will occur and increase the co-efficient of friction. friction.

• Viscosity is measured by the Viscosity is measured by the Say bolt UniversalSay bolt Universal Viscosity Viscosity TestTest which measures the number of seconds for a definite which measures the number of seconds for a definite quantity of oil to flow through a fixed orifice into a quantity of oil to flow through a fixed orifice into a measured container at a specified temperature. measured container at a specified temperature.

Viscosity Index ImproverViscosity Index Improver• Polymer additive that induces thickening of a thin base oil at Polymer additive that induces thickening of a thin base oil at

high temperatureshigh temperatures

• 10W30 oil starts as a 10W oil and viscosity index improvers 10W30 oil starts as a 10W oil and viscosity index improvers are added in sufficient quantity to bring theare added in sufficient quantity to bring the high high temperature viscosity ratingtemperature viscosity rating up to the S.A.E. 30 standard. up to the S.A.E. 30 standard.

• VI improvers make up between 6 and 15% of the oilVI improvers make up between 6 and 15% of the oil

• VI improvers breakdown with useVI improvers breakdown with use

• Oil oxidizes and thickens forming sludge Oil oxidizes and thickens forming sludge

YouTube - oil aditives

These oils were chilled to -35C for 16 hours. The These oils were chilled to -35C for 16 hours. The photo was taken 30 seconds after the caps were photo was taken 30 seconds after the caps were removed from the containers. removed from the containers.

YouTube - Tech Talk on Engine Oil - with Castrol

S.A.E. Oil Viscosity RatingsS.A.E. Oil Viscosity Ratings• Grade number represents the viscosity Grade number represents the viscosity rangerange of an oil of an oil• A grade number with no letter following means that oil was A grade number with no letter following means that oil was

tested only at 100C (212F) eg. SAE 10, 20 30tested only at 100C (212F) eg. SAE 10, 20 30• The higher the number the higher the viscosityThe higher the number the higher the viscosity

• Grade numbers that are followed by a the letter “W” indicate Grade numbers that are followed by a the letter “W” indicate that the oil was tested at -18C (0F) and are given a viscosity that the oil was tested at -18C (0F) and are given a viscosity rating at that temperature. eg. 10W, 20W rating at that temperature. eg. 10W, 20W

• Multigrade oils like 10W30 are tested at -18C and 100C and Multigrade oils like 10W30 are tested at -18C and 100C and meet the S.A.E. specifications for those temperaturesmeet the S.A.E. specifications for those temperatures

(VI improvers are added to meet these specifications)(VI improvers are added to meet these specifications)

A.P.I. Ratings - Oil QualityA.P.I. Ratings - Oil QualityAmerican Petroleum InstituteAmerican Petroleum Institute • Letter Ratings that are applied to oils tested for qualityLetter Ratings that are applied to oils tested for quality

GasolineGasoline engine ratings engine ratings• ““S” means Service (spark ignition)S” means Service (spark ignition)

• Ratings from Ratings from SASA (straight mineral oil) to SL. (straight mineral oil) to SL.

• SL is the highest rated oil starting in 2001.SL is the highest rated oil starting in 2001.

• Use the highest rated oil available (or as specified)Use the highest rated oil available (or as specified)

A.P.I. Ratings - Oil QualityA.P.I. Ratings - Oil QualityDiesel engine ratingsDiesel engine ratings• ““C” means Commercial (compression ignition)C” means Commercial (compression ignition)

• Ratings from Ratings from CACA (obsolete) to (obsolete) to CG4CG4 which is for which is for severe duty high speed four stroke diesel engines.severe duty high speed four stroke diesel engines.

• Always use the correct oil for the applicationAlways use the correct oil for the application

ILSAC Oil RatingILSAC Oil RatingInternational Lubricant Standardization International Lubricant Standardization

and Approval Committeeand Approval Committee• Combination of SAE Viscosity and API Quality ratings Combination of SAE Viscosity and API Quality ratings • GF1 - pre 1996GF1 - pre 1996• GF2 - 1997 to 1999GF2 - 1997 to 1999• GF3 - 2000GF3 - 2000• Starburst SymbolStarburst Symbol

Synthetic OilsSynthetic OilsBase Stocks not from crude oilBase Stocks not from crude oil

Polyalphaolefins - Mobil 1Polyalphaolefins - Mobil 1

Organic esters - alcohol and acid - Castrol SyntecOrganic esters - alcohol and acid - Castrol Syntec

Polygycols - polyalkaline gylcol (PAG oil for 134a A/C)Polygycols - polyalkaline gylcol (PAG oil for 134a A/C)

AdvantagesAdvantages • remains fluid at very low temperaturesremains fluid at very low temperatures• lower internal friction - fuel economy and cooler enginelower internal friction - fuel economy and cooler engine• resists oxidation resists oxidation

DisadvantagesDisadvantages• $ cost $ - 4 to 5 times more money$ cost $ - 4 to 5 times more money• may not be compatible - gaskets, seals = oil leaksmay not be compatible - gaskets, seals = oil leaks