Understanding Automotive Oil What do the numbers and letter mean?
Possible Functions of an Engine Oil LUBRICATE COOL CLEAN (Detergency & Dispersion) SEAL CORROSION PROTECTION MAINTAIN OIL SEAL FLEXIBILITY WEAR PROTECTION FOAM PROTECTION FRICTION REDUCTION PREVENT WAXING NOISE REDUCTION PRESSURE SEALING IMPROVED FUEL ECONOMY REDUCTION OF EMISSIONS LONG TERM ENGINE DURABILITY EXTENDED OIL DRAIN POTENTIAL
Lubricant governing bodies API American Petroleum Industry SAE Society of Automotive Engineers ACEA Association des constructeurs Europeene d`automobiles
Motor Industry Demands for the Lubricant Minimise wear and deposits at high & low engine temperatures complex valve mechanisms Reduce servicing costs Low oil consumption Longer drain intervals greater performance reserve Improved Diesel engine performance Better soot control Towards petrol engine drain intervals
Engines have become SMALLER LIGHTER FASTER HOTTER TOUGHER CHEAPER MORE POWERFUL CLEANER SMOOTHER RUNNING MORE ENVIRONMENTALLY ACCEPTABLE... and more difficult to lubricate. THE LUBRICANT HAS BECOME A PART OF THE ENGINE DESIGN PROCESS
Engine Design Strategies Advanced Engine Technology High speed multivalve petrol & diesel Direct injection Variable valve timing & inlet tuning Exhaust catalysts Fast warmup Electronic Control Adaptive computer tuning from multiple sensors Service related control strategies
Engine oil makeup BASE OILS / FLUIDS MINERAL AND/OR SYNTHETIC ADDITIVES VISCOSITY MODIFIERS DETERGENTS AND DISPERSANTS ANTIOXIDANTS POUR POINT DEPRESSANTS CORROSION & RUST INHIBITORS FRICTION MODIFIERS MISCELLANEOUS ADDITIVES
NUMBERS and LETTERS on ENGINE OILS LETTERS API (USA) SJ, SH, SE, etc. CC, CD, CF, CF4, etc. ACEA (Europe) A1, A2, A3 B1, B2, B3 & B4 NUMBERS 20W50, 15W40, 0W30, 10W60 What do they stand for?
NUMBERS and LETTERS on ENGINE OILS NUMBERS 20W50, 15W40, 0W30, 10W60 Numbers relate to viscosity of oil. LETTERS API(USA) SJ, SH, SE, etc. CC, CD, CF, CF4, etc. ACEA (Europe) A1, A2, A3 B1, B2, B3 & B4 Relate to Performance Rating of oil.
Viscosity MEASURE OF THE RESISTANCE TO FLOW OF A FLUID Low viscosity (thinner or lighter) less resistance to flow High viscosity (thicker or heavier) more resistance to flow VISCOSITY SAE ENGINES & GEARS W Rating is a measure of cold start fluidity lower numbers mean more fluid at low temperatures Plain number rating is a measure of oil viscosity at 100 C operating temperature higher numbers mean thicker oil, more resistance to flow when hot
SAE J300 Viscosity Grades for Engine Oils SAE Viscosity Grade Viscosity (cp) at Temperature C Max Borderline Pumping Temperature C Viscosity (cst) at 100 C Max Min Max High Shear Viscosity, (cp) at 6 1 150 C & 10 S Min 0W 5W 10W 15W 20W 25W 3250 at 30 3500 at 25 3500 at 20 3500 at 15 4500 at 10 6000 at 5 35 30 25 20 15 10 3.8 3.8 4.1 5.6 5.6 9.3 20 30 40 40 50 60 5.6 9.3 12.5 12.5 16.3 21.9 Less than Less than Less than Less than Less than Less than 9.3 12.5 16.3 16.3 21.9 26.1 2.6 2.9 2.9* 3.7** 3.7 3.7 * (0W40, 5W40 and 10W40 grades) ** (15W40, 20W40, 25W40, 40 grades)
MULTIGRADE ENGINE OILS What Multigrades mean & Why put two numbers on the one oil? Specified the start up and operating temperature viscosity characteristics of the oil Is choice of viscosity important? Sometimes very! eg Ford Explorer, Suzuki Swift GTi, Holden Jackaroo (diesel) WHAT IS THE SOLUTION? Check with the Castrol Lubrication Reference Guide What about some of other numbers out there? 40W70, HPR 30 (25w60), HPR 50 (40W70) possibly misleading Newer engines engineered for lower viscosity oils improved fuel economy improved engine responsiveness better power output Thick oils and high volume oil pumps usually a bad combination
VISCOSITY GRADES in INDIA What are the most common viscosity grades used in India? SAE 20W40, 20W50 SAE 15W40, 15W30 SAE 25W50 FUTURE GRADES SAE 10W30, 5W30 SAE 0W20, 5W20???
ENGINE OIL PERFORMANCE RATINGS PETROL API (US based) SJ, SH, SG, SF SJ supersedes SH, SG, etc. ILSAC GF2 = SJ + Fuel Eco ACEA (European) A1, A2, A3 A1 = A2 + Fuel Eco A2 = SJ + Eng, bench & physical & chemical A3 = Premium, High Performance, longer drain DIESEL API CF, CD, CC CF2, CDII CH4,CG4, CF4 CF2 Two cycle diesels CF4 Four cycle heavy duty diesel, emission controlled ACEA B1, B2, B3 Light commercial and passenger car diesels higher standard than CF!
Viscosity Index Improvers OIL SOLUBLE POLYMERS THAT RETARD THE RATE OF VISCOSITY LOSS WITH INCREASE IN TEMPERATURE VISCOSITY SAE 50 SAE 20W 50 SAE 20 18 C 100 C TEMPERATURE
API Specifications CMA code of practice Base oil interchange guidelines Viscosity grade read across guidelines SH SJ PERFORMANCE SF 1980 SG Introduction of Sequence IIIE test Introduction of Sequence VE test Introduction of 1H2 test high temp deposits 1989 1994 1996 TEOST oxidation test L38 shear stability requirement Sequence IV foam test GM Filterability test Homogeneity test Tighter Phosphorus & Volatility
Introduction of ACEA Sequences ACEA "Association des Constructeurs Europeene d'automobile" BMW/Rover DAF Fiat GM/Opel MAN Mercedes Benz Porsche PSA Peugeot Citroen Renault Rolls Royce Saab/Scania VW/Audi group Volvo
Lubricant Oxidation Stability Good Poor antox1a.tif
Sludge Prevention 1 2 1
3 Key Lubrication Areas VALVE TRAIN BEARINGS PISTONS... and areas of increased Castrol development focus.
Camshaft Lubrication 2 5 4 1 5 4 3
Bearing Protection 1 3 1 4 2 5 7 6
Piston Cleanliness + 800 C Deposits Buildup 1 2 Stuck Piston Ring Varnish 5 Wear 4 3 BlowBy Gases
SYNTHETICS WHAT ARE THEY TAYLOR MADE MOLECULES CONTROLLED SHAPE AND SIZE MANY MANY TYPES POSSIBLE ONLY A FEW USEFUL & AFFORDABLE SOME DESCRIBE BASE OILS WITH SOME PHYSICAL PROPERTIES LIKE SOME SYNTHETICS AS SYNTHETICS ALSO REFERRED TO AS HYDROCRACK OILS EITHER A MARKETING OR TECHNICAL DEFINITION
The case for Synthetics HIGH VISCOSITY INDEX LOW FRICTION EXCELLENT OXIDATION RESISTANCE LOW VOLATILITY FREE FLOWING AT VERY LOW TEMPERATURES REDUCED WEAR AT STARTUP POTENTIAL FOR LONGER LIFE
SUMMARY THERE IS A SYSTEM FOR VISCOSITY SAE FOR APPLICATIONS API & ACEA ONLY RELATE TO EVERYDAY APPLICATIONS NOT RACING etc..
What is different today from five years ago? The amount of change Rate of change OEM consolidation Oil industry rationalistion Margins being squeezed Everyone wants a share of someone else's pie New industry and OEM standards Customer demands and expectations Legislative requirements
Why are things changing so fast? Emission requirements around the world Montreal protocol More global competition Need to change processes and technology to get step improvements Global communication drives competition and customer expectation What can we do about any of those factors? Adapt There is always opportunity with change OEM's produce global models Oil spec's and protocols global More fillforlife oils Reduced lifetime cost Reduced eco pollution Long drain oils
How do we continue to improve the performance of oil New and Revised Technology Changing and creating new molecules Revised base oils More intense refining New processes Higher treats of active materials More inhibitors
How are oils degraded in "normal" service What is normal service? For most people commuting Everyone thinks what they do is normal So what does commuting mean? Relatively short trips Drive to work, school, shops, etc. Result is a lot of cold or warm running lots of idling little highway cruise Few extremes of temperature and RPM so people think it is easy on the engine and oil Wrong!!!! Virtually all engines are MPI with 3 way catalysts What air fuel ratio do they run engines with 3 way catalysts? stoichiometric which results in near maximum NOx production At low oil temperatures, less than 75 C some of the gases in NOx react much faster with the oil than at high temperatures The reaction is called NITRATION
How are oils degraded in "normal" service (cont..) Makes the oil chocolate brown many reaction products oil insoluble Result is SLUDGE! Can block OHC oilways, cover rocker gear Fuel dilution in modern MPI engines not a normal problem, only if there is a fault with the system Nitration degrades base oils and additives Higher quality base oils, including synthetics are more resistant to nitration Some detergent/dispersant additives more resistant than others to nitration Everyone talks oxidation, we think NITRATION is more the issue
How are oils degraded in "normal" service (cont..) What potentially happens if you change the oil in a heavily sludged engine? New oil will lift some of the sludge in large flakes These can block oil pick up Result is? Low oil pressure Is the oil low? NO But we can still get bearing failure Higher loading of the oil kw of engine output / sump capacity is a measure Less oil volume means oil works harder If the oil pickup is blocked the oil will not get through to the bearings So time, lots of short trips, is an effective oil service indicator Which engines last longer family hacks or taxis? everyone knows Antiwear additives work better at higher temperatures too
Future oils Synthetic and more highly refined base oils Higher treats of detergent/dispersant additives new detergent and dispersant materials Lower viscosity 10w30, 5w30, 0w20, 0w30, etc. Modern engines are engineered for low vis oils advantages? better fuel economy improved engine responsiveness from cold NOT always suitable for older cars They suit most modern Japanese and US vehicles Some Australian models Two types of low vis oils best defined in ACEA classifications Petrol A1 fuel efficient HTHS 2.9 to <3.5 cp Petrol A2 & A3 HTHS 3.5 cp or higher HTHS 3.5 and above widely called up by European OEM's for bearing durability at high temperatures and high load
Future oils SAE 5 & 10W 30 oils can be either above or below 3.5 cp ILSAC GF2 or ACEA A1 less than 3.5 cp, normally less than 3.1 cp ACEA A2 or A3 must be 3.5 cp minimum Other issues with low viscosity oils Oil consumption noise oil pressure How do we address these? Oil consumption is engine design and manufacture influenced as well as oil design We try to minimise oil volatility how readily it evaporates at high temperature how easily is it carried by the crankcase breathing system into the engine Lower "W" rated oils need base oil with greater fluidity at low temperatures smaller oil molecules more volatile evaporate more readily Synthetics and other special base oils can provide a better combination of low temperature fluidity and high temperature volatility Problem is they cost more! more processing means higher cost
Thank you for your attention!!