GUIDELINES FOR DIESEL ENGINES LUBRICATION

1 GUIDELINESFOR DIESEL ENGINESLUBRICATIONOIL DEGRADATIONN umber 22 2004 The International Councilon combustion EnginesConseil International desMachines CombustionCIMAC is an international organisation, founded in 1950 by a Frenchinitiative to promote technical and scientific knowledge in the field ofinternal combustion ENGINES (piston ENGINES and gas turbines). This isachieved by the organisation of congresses and working is supported by engine manufacturers, engine users, technicaluniversitites, research institutes, component suppliers, fuel andlubricating oil suppliers and several other interested National Member Associations and previous CIMACR ecommendations still available are listed in the back of this document has been elaborated by the CIMAC Working Group Marine Lubricants and approved by CIMAC in April INTERNATIONALDES MACHINES A COMBUSTIONINTERNATIONAL COUNCILON combustion ENGINESF oreward by the PresidentThe CIMAC Recommendations are produced by the CIMAC Working Groups inwhich experts in the various fields of combustion ENGINES , contribute voluntarily.

2 To formulate the related CIMAC Recommendations serve not only to consolidate the knowledge andexpertise in a particular field, but are also aimed to be of practical importance forengine users, manufacturers and related equipment present Recommendations on GUIDELINES for DIESEL engine LUBRICATION -Lubricating Oil Degradation is targeted to all people related to large ENGINES inmarine propulsion, land-based power generation and railroad Recommendation is one further product of the CIMAC Working Group No. 8. Lubricants , which can boast a very wide participation of experts from CIMACM embers and has been very fruitful in producing Recommendations over the wish to congratulate the Working Group No. 8 Lubricants for this finedocument, which I trust will be useful for the combustion engine community allover the Nikolaos P.

3 KyrtatosApril 20041 GUIDELINES FOR DIESEL engine LUBRICATIONLUBRICATING OIL DEGRADATION2 OIL DEGRADATIONCONTENTS STRESSES IMPOSED ON THE engine OILS BY engine PRINCIPAL FUNCTIONS OF engine TYPES OF LUBRICANT FOR LARGE DIESEL ENGINES ANDTHEIR Crosshead engine Cylinder System Medium Speed Trunk Piston engine High Speed Trunk Piston engine CAUSES OF OIL Factors Affecting Oil Specific Lube Oil Specific Lube Oil System Oil Circulation NOx Content in the Crankcase Atmosphere and Influence on Fuel Contamination in Trunk Piston Deposition Tendency on the Cylinder Liner Metals in Lubricant Oil Top-up Summary of Factors Influencing Oil LUBRICANT PERFORMANCE IN SERVICE AS INFLUENCED BY engine Lube Oils for High and Medium Speed Trunk Piston DIESEL Oils for Two-Stroke Crosshead DIESEL Physical Chemical Physical Oil Film THE MECHANISM OF OIL DEGRADATION & MEASURABLE RESPONSES Changes in Oil The Formation of Changes in BN (Base Number).

4 Increase of TAN (Total Acid Number).. Flash Point Chemical Change in Molecular Weight Particle Size Process of Degradation of Characteristics of Oils in Use and their PRACTICAL IMPLICATIONS AND FUTURE Designing More Stress-Resistant Environmental ANALYTICAL METHODS FOR ASSESSING OIL WARNING AND CONDEMNING 1. A Mathematical Model simulating Insolubles Build-Up in used engine 2. Oxidation 3. What is Acid ?..5014. DEGRADATIONPREFACEThis document brings together insights into mechanisms and phenomena of oildegradation resulting from stress of the lubricant in large 4-stroke (medium speed andhigh speed) and 2-stroke DIESEL ENGINES . Its objective is to contribute to the understandingof the complex processes resulting in oil degradation and thereby, to a degree, enablecontrol of them so that the ENGINES , their treatment systems and the lubricant itself remainin an acceptable condition for an acceptable intended readership of this document are all people related to large ENGINES inmarine propulsion, land based power-generation and railroad industry - for exampleusers and producers of equipment, students and newcomers to the industry INTRODUCTIONThe lubricating oil for a DIESEL engine needs a variety of properties.

5 It must be able toclean engine components and keep them clean, it must neutralize acids, transfer heat,fight rust and corrosion in addition to its main job of lubricating the engine for a very longtime [1, 2]. Since lubricating oil is a product influenced in its quality by a variety ofstresses, monitoring of the oil quality, adequate oil maintenance, as well as its timelyreplacement if needed (partially or totally) must be ensured. Also, the selection of the typeand grade of lubricant to be used should be based on the relevant engine operatingconditions and service document discusses the types, causes and counter measures of degradation oflarge engine lubricants during service. Oil degradation in this document means thechange in physical and chemical properties of the lubricants during service that result indeterioration of performance.

6 The change in oil quality is the result of a) accumulation ofcontaminants including combustion soot, acidic combustion blow-by products, rawresidual fuel, water, etc., and b) the influence of high temperature, aeration and document gives advice on how to maintain oil properties within acceptable STRESSES IMPOSED ON THE engine OILS BY engine COMPONENTSThis section compiles a list of the different stresses a lubricant experiences in an also serves as a guide for engineers to understand why attention needs to be paid tolubricant properties as part of routine engine maintenance. Some of the componentsmentioned in this section are marked in which shows a typical Crosshead and Trunk Piston DIESEL engine . [3].Stresses on the lubricant are listed in Table 1. A lubricant can degrade through a numberof routes, therefore users need to be aware of how engine operation can affect lubricantproperties and the importance of carrying out maintenance and preventive work tominimize engine wear and 1: engine Components relevant for LUBRICATION [3](Courtesy of Mitsubishi Heavy Industries and Niigata Power Systems)6 Table 1: Stresses on Lubricating Oils of Large DIESEL EnginesNo.

7 engine component :Function of the oil :Oil type used incrosshead engine :Oil type used intrunk pistonengine :Stresses on oil :1 Main bearingLubrication, coolingSystem oilSystem oilLoad, heat2 Crank pin bearingLubrication, coolingSystem oilSystem oilLoad, heat3 Crosshead and conrodBearingsLubrication, coolingSystem oilSystem oilLoad, heat4 Cylinder liner, pistonring and piston ringgrooveLubrication, wear control,sealing, cleaning,neutralization,Cylinder oil, highlyalkalineSystem oil,medium alkalineLoad, heat, dirt,acids5 Piston undercrownCooling, cleaningSystem oilSystem oilHeat, dirt6 Crosshead guides andShoeLubricationSystem oil-Load, heat7 Thrust bearingLubricationSystem oilSystem oilLoad, heat8 Camshaft drive gearLubricationSystem oilSystem oilLoad, heat9 Cam, roller, rollerguidesLubricationSystem oilSystem oilLoad, heat, fuel10 Exhaust valve drivegearHydraulic action,lubricationSystem oil-Load, heat11 Exhaust valve shaft.

8 Valve guideLubrication, sealing,neutralizationCylinder oil orsystem oilSystem oilLoad, heat, dirt,acids12 Fuel injection pumpLubrication, sealingSystem oilSystem oilLoad, dirt, fuel13 Piston rod stuffing boxLubrication, sealingSystem oil andcylinder oil-Load, dirt, acids14 Turbo charger rotorbearingsLubrication, coolingSystem oil orturbine oilSystem oil orturbine oilLoad, heat15 Tie rodDampingSystem oil-Load, heat16 Axial/torsional vibrationdampers *DampingSystem oilSystem oilLoad, heat17 Turning gearLubricationGrease / OilLoad* Some torsional vibration dampers operate with their own dedicated oil73. PRINCIPAL FUNCTIONS OF engine OILSB asically, the principal functions of the engine lubricant are as follows. See also [4]:1. Reduce friction2. Minimize wear of engine components including corrosive wear3. Removal of heat4.

9 Protection of engine components against harmful deposits5. SealingApart from these basic functions, the lubricants are also expected to control against anydeposit formation in the LUBRICATION system (circulation lines, check valves and sightglasses).In merchant marine terminology as shown in Table 2, DIESEL engine lubricants areclassified as follows:1. Cylinder oils2. System oils for crankcase LUBRICATION of crosshead engines3. Crankcase oils for medium or high speed trunk piston enginesTable 2: DIESEL engine ClassificationDiesel engine ClassificationRotational Speed (rpm)CrossheadBelow 300 Medium Speed Trunk PistonBelow 1000 High Speed Trunk PistonAbove 1000 Note : There are some older design ENGINES of the two-stroke (trunk-piston) type with rpm of above TYPES OF LUBRICANT FOR LARGE DIESEL ENGINES AND THEIRREQUIREMENTSD ifferent physical properties and performance levels are required for different lubricantsdepending on the applications.

10 A discussion on oil degradation is, therefore, dependent ofthe lubricant type and of large DIESEL engine lubricants are shown in Table 3: Requirements of DIESEL engine LubricantsCrosshead EngineCylinder oilsSystem oilsTrunk PistonEngine -Medium SpeedTrunk PistonEngine -High SpeedWear Control(Rings /Liners)**Thermal and Oxidation Stability**Piston Deposit ControlRing grooves, Lands,Undercrown**Detergency/Dispersancy ( engine cleanliness)**Retention of Alkalinity* (against water wash)**Water Separability**Rust Inhibition**Filterability**Free of gelling tendencies**Load-carrying property for reductiongears*Load-carrying property for valve-trainarea**Load-carrying property for hydraulicfunctions* Crosshead engine Oils [5]Crosshead ENGINES generally burn residual fuels. In this type of engine , separate systemsare used for:- cylinder LUBRICATION (which is a total-loss system) and crankcase lubricationDifferent properties are required for the oils used for these two applications.