CN105713703A

CN105713703A - Marine engine lubrication

Info

Publication number: CN105713703A
Application number: CN201510957584.6A
Authority: CN
Inventors: J·C·多德; A·索耶; J·V·辛普金斯; J·H·斯迈思
Original assignee: Infineum International Ltd
Current assignee: Infineum International Ltd
Priority date: 2014-12-19
Filing date: 2015-12-18
Publication date: 2016-06-29
Anticipated expiration: 2035-12-18
Also published as: AU2015271928B2; EP3034587A1; CA2915701A1; EP3034587B1; CN105713703B; CA2915701C; ES2759077T3; JP2016117900A; AU2015271928A1; SG10201510456QA; KR20160075361A

Abstract

Trunk piston marine engine crankcase lubrication is effected by a composition that includes a nitrogen-containing ashless dispersant additive component in an amount providing in the range of 50 to 150 ppm N by mass to diminish loss of BN and diminish increase of viscosity during use of the composition without adversely affecting deposits performance.

Description

Marine engine lubrication

Technical field

The present invention relates to the lubrication of 4-stroke marine diesel explosive motor (being commonly referred to trunk-piston engine).Lubricant used is commonly referred to trunk-piston engine oil (" TPEO ").

Background of invention

Trunk-piston engine can be used for transporting by sea, generate electricity and in rail traction application and can have the speed higher than crosshead engine.Single lubricant (TPEO) is for crankcase and cylinder lubrication.All major moving part of electromotor, namely main and big-end bearing, camshaft and valve gear pass through pumping circulation system lubrication.Cylinder sleeve partially by splash lubrication and partially by the oil lubrication carrying out self-circulation system, described come self-circulation system oil arrive cylinder wall via connecting rod and piston pin by the hole in piston skirt.Trunk-piston engine generally includes centrifuge to clean TPEO.

Nitrogenous ashless dispersant is known in the art the additive as TPEO.Referring to such as EP-A-2133740；US-A-2009/0203559；US-A-2009/0011966；EP-A-1528099 and EP-A-1209218.

But, this area does not mention that base number (BN) is reduced the impact of (dimunition) by nitrogenous ashless dispersant in TPEO use procedure；Also without mentioning its impact that viscosity is increased.

Summary of the invention

It has now been found that use nitrogenous ashless dispersant that BN and viscosity are had favorable influence in TPEO with limited amount, without negatively affecting deposit performance.

Therefore, the invention provides nitrogenous ashless dispersants agent addition agent to provide 50-150, the amount of preferred 75-125 mass ppmN purposes in pot type piston marine lubricant compositions, described pot type piston marine lubricant compositions for being supplied fuel the medium speed compression ignition marine engine lubricated by said composition by heavy oil, described compositions has 20-60, the BN of preferred 30-55, described purposes is to reduce BN loss and reduce viscosity increase, without negatively affecting deposit performance, preferably compared with the similar application when the amount of nitrogenous ashless dispersant is outside above-mentioned scope.

In this manual, following word and statement (and if when deployed) have meaning given below:

" active component " or " (a.i.) " refers to it is not the additive materials of diluent or solvent；

" comprise " or any same speech like sound illustrates there is the feature, step or the overall or component that give, but do not preclude the presence or addition of one or more other features, step, entirety, component or their combination；Expression formula " by ... constitute " or " mainly by ... constitute " or similar expression formula can include within " comprising " or similar statement, wherein " mainly by ... constitute " allow to include the material of the not characteristic of its compositions applied of materially affect；

" primary amount " refers to the 50 mass % or more of compositions, it is preferable that 60 mass % or more, even more preferably from 60 mass % or more, it is most preferred that 70 mass % or more；

" minor amount " refer to compositions less than 50 mass %, it is preferable that less than 40 mass %, be even more preferably less than 30 mass %, it is most preferred that less than 20 mass %；

" TBN " refers to that " BN " has same meaning by the ASTMD2896 total base number measured.

It addition, in this manual, and if when deployed:

" calcium content " is measured by ASTM4951；

" phosphorus content " is measured by ASTMD5185；

" sulfate ash content " is measured by ASTMD874；

" sulfur content " is measured by ASTMD2622；

" KV100 " refers to by the ASTMD445 100 DEG C of kinematic viscositys measured.

Moreover, it will be appreciated that the various components used (basic and the best and conventional component) are likely to the reaction when preparation, storage or use, the present invention also provides for being reacted, by any this type of, the product that can obtain or obtain.

Also, it should be understood that any upper and lower bound amount given herein, scope and ratio can combine independently.

Detailed description of the invention

Discuss inventive feature in further detail below.

Pot type piston marine engine oil compositions (" TPEO ")

TPEO can use 7-35 mass %, it is preferable that 10-28 mass %, more preferably the concentrate of 12-24 mass % or additive bag, oil plant (oil of lubricant viscosity) based on all the other.Preferably, TPEO has 20-60, it is preferable that 25 or the composition TBN (use D2896) of 30-55.

Hereinafter can mention as the typical proportions of additive in TPEO.

When using multiple additives, it is possible to cater to the need but not necessarily, prepare one or more additive bag comprising described additive or concentrate, thus can multiple additives is simultaneously introduced in the oil of lubricant viscosity to form lubricant oil composite.Described additive is wrapped in the dissolving in lubricating oil and can be promoted by solvent and promoted by the stirring with mild heat, but this is dispensable.Described additive bag is generally formulated to appropriate amount and contains additive thus providing desired concn, and/or when described additive bag and scheduled volume base lubricant in conjunction with time in end formulation, play expectation function.Therefore, can blend to form the additive bag comprising active component by the additive according to the present invention and a small amount of base oil or other compatible solvent and other desired additives, the amount of described active component is such as 2.5-90 mass % based on additive bag, preferred 5-75 mass %, the most preferably properly mixed additive of 8-60 mass %, all the other are base oil.

Nitrogenous ashless dispersant

Dispersant is the additive of lubricating composition, and its major function is to maintain solid and liquid pollutant thing is suspended state, reduces sludge deposition thus being passivated them with reducing engine deposits simultaneously.It is therefoie, for example, it is suspended state that dispersant maintains the oil-insoluble substance produced by the oxidation in lubricant use procedure, thus prevents sludge flocculation and precipitation or be deposited on the metal parts of electromotor.

" ashless " refers to that dispersant is non-metallo organic material, and with containing metal, the material therefore forming ash is different, and it is substantially formed without ash when burning.Ashless dispersant comprises the long-chain hydrocarbon with polar head, and this polarity stems from and includes such as O, P or atom N, in the present invention, including atom N.Described hydrocarbon is to confer to oily deliquescent lipophilic group, has such as 40-500 carbon atom.Therefore, ashless dispersant can comprise oil-soluble polymeric hydrocarbon main chain, and this main chain has can with the functional group treating that scattered granule is combined.Generally, dispersant comprises the amine, alcohol, amide or the ester polar moieties that are generally connected with main polymer chain via bridging group.Described ashless dispersant is passable, for instance, selected from monocarboxylic acid and the oil-soluble salt of dicarboxylic acids or their anhydride, ester, amino ester, amide, acid imide and the azoles quinoline of the replacement of long-chain hydrocarbon；The thiocarboxylic acid salt derivative of long-chain hydrocarbon；There is the long chain aliphatic hydrocarbon being directly connected in polyamines thereon；And the Mannich reaction products by the phenol that long-chain is replaced and formaldehyde and polyalkylenepolyamines condensation formation, for instance those described in US-A-3,442,808.

Described oil-soluble polymeric hydrocarbon backbone is usually olefin polymer or polyenoid, particularly comprises the C of (that is, more than 50mol%) of main mole₂-C₁₈Alkene (such as, ethylene, propylene, butylene, isobutene., amylene, octene-1, styrene), usual C₂-C₅The polymer of alkene.Described oil-soluble polymeric hydrocarbon backbone can be homopolymer (such as, polypropylene or polyisobutylene) or two or more such alkene copolymer (such as, the copolymer of ethylene and alpha-olefin such as propylene or butylene, or the copolymer of alpha-olefin two kinds different).Other copolymer includes following those, wherein the polymer monomers of minority molar amount, for instance, 1-10mol%, is α ω-diene；Such as C₃-C₂₂Non-conjugated diene (such as, the copolymer of isobutene. and butadiene, or the copolymer of ethylene, propylene and Isosorbide-5-Nitrae-hexadiene or 5-ethylidene-norbornene).The atactic propylene oligomer of the Mn being generally of 700-5000 can also be used, as described in EP-A-490454, and heteropolymer such as polyepoxide.

The one preferred olefin polymer of class is polybutene, particularly polyisobutylene (PIB) or poly-n-butene, for instance can pass through C₄Those of the polymerization preparation of refiner streams.The olefin polymer of other preferred classes is ethylene ' alpha '-olefin (EAO) copolymer and alpha-olefin homo and the copolymer in each case with height (such as > 30%) the terminal ethylene fork unsaturated part of base, such as, described in WO-94/13709 those, it functionalized can obtain dispersant with amination.

Dispersant includes such as, the derivant of the carboxylic acid that long-chain hydrocarbon replaces, and example is the derivant of the succinic acid that high molecular alkyl replaces.One group of noticeable dispersant is the butanimide that hydrocarbon replaces, and this butanimide is such as by making above-mentioned acid (or derivant) and nitrogen-containing compound, it is advantageously that polyalkylenepolyamines, for instance polyethylene polyamine reaction prepares.Preferably, alkyl is polyalkenyl.This type of polyalkenyl (such as polybutylene-based) structure division can have 200-3000, it is preferable that 350-1000, more preferably 400-960, or the number-average molecular weight of 400-950.In particular it is preferred that the product of polyalkylenepolyamines and alkenyl succinic anhydride, for instance US-A-3,202,678；-3,154,560；-3,172,892；-3,024,195；-3,024,237；-3,219,666 and-3,216,936 and BE-A66, those described in 875, they can be post-treated to improve their performance, for instance boration (such as US-A-3,087,936 and-3,254, described in 025)；Fluoride and oxygen base.For example, it is possible to realize boration by processing the dispersant of acyl nitrogen-containing with the boron compound selected from boron oxide, halogenation boron, boronic acid containing and borated ester.

As discussed, dispersant provides 50-150 mass ppmN atom for TPEO.

Common additive be will be described in more detail now.

Metal detergent

Detersive is reduce the additive that in electromotor, deposit such as high temperature varnish and lacquer deposits are formed；It has acid and neutralizes performance and subdivided solids can be kept to suspend.It, based on metal " soap ", is the slaine of acidic organic compound, is sometimes referred to as surfactant.

Detersive comprises the polar head with long hydrophobic tail.A large amount of metal base are included thus obtaining overbased detergent by excess metal compound such as oxide or hydroxide and sour gas such as carbon dioxide reaction, and described overbased detergent comprises the detersive outer layer as metal base (such as carbonate) micelle of neutrality sum.

Detersive is preferably alkali metal or alkaline-earth metal additive such as the parlkaline oil-soluble of the surfactant selected from phenol, sulfonic acid, carboxylic acid, salicylic acid and aphthenic acids or oil-dispersing property calcium, magnesium, sodium or barium salt, wherein parlkalineization is provided by oily the insoluble salt such as carbonate, basic carbonate of metal, acetate, formates, hydroxide or oxalates, and it is salt-stabilized by the oil-soluble of surfactant.The metal of oil soluble surfactant salt can be identical or different with the metal of oil insoluble salt.Preferably, the no matter metal of oil-soluble or oil insoluble salt, described metal is calcium.

The TBN of detersive can be low, namely less than 50mgKOH/g；Medium, i.e. 50-150mgKOH/g；Or high, namely measured by ASTMD2896 more than 150mgKOH/g, TBN.Preferably, TBN is medium or high, i.e. 50TBN or more.It is further preferred that be at least 60 by the ASTMD2896 TBN measured, more preferably at 100, more preferably at 150, at most 500, for instance at most 350mgKOH/g.

Preferably, detersive comprises the hydroxy benzoic acid alkaline earth salt such as Calcium Alkylsalicylate that alkyl replaces.

Term used herein " oil-soluble " or " oil-dispersing property " not necessarily referring to compound or additive can, solubilized solvable with all proportions, can miscible, maybe can be suspended in oil.But, these terms are actual to be meant them and such as dissolves in or be stably dispersed in oil and play they degree being intended to effect in the environment using oil to being enough to.Additionally, if necessary, the additional introducing of other additive can also allow to introduce higher levels of special additive.

Lubricant compositions of the present invention comprises each (namely independent) component of restriction, and these components are before mixing and are likely to keep or be likely to not keep chemically identical later.

Other common additive

The lubricant oil composite of the present invention can comprise other additive.This type of extra additive is passable, it may for example comprise other metal detergent, antiwear additive, for instance, ZDDP, antioxidant such as amine or phenol antioxidant and demulsifier.

The oil of lubricant viscosity

The lubricating oil existed as the major portion of TPEO can be light fraction mineral oil to heavy grease in viscosity.It is said that in general, the oil viscosity scope measured at 100 DEG C is from 2 to 40mm²/sec。

Natural oil includes animal oil and vegetable oil (such as Oleum Ricini, Adeps Sus domestica)；The mineral oil of liquid petroleum and alkane, cycloalkanes and the mixing alkane-hydrotreatment of naphthene types, solvent process or acid treatment.The oil being derived from the lubricant viscosity of coal or shale also serves as useful base oil.

Synthetic lubricant fluid includes the hydrocarbon ils of hydrocarbon ils and halo, such as polymerization and mutual olefin polymerization (such as, polybutene, polypropylene, propylene-isobutylene copolymers, chlorinated polybutylenes, poly-(1-hexene), poly-(1-octene), poly-(1-decene))；Alkylbenzene (such as, detergent alkylate, Tetradecylbenzene, dinonyl benzene, two-(2-ethylhexyl) benzene)；Many benzene (such as, biphenyl, terphenyl, alkylating polyphenol)；With alkylating diphenyl ether and alkylating diphenyl sulfide and derivant, analog and homologue.

Wherein terminal hydroxy group is modified, for instance constitute another kind of known synthetic lubricant fluid by esterification or etherification modified oxyalkylene polymer and interpretation and their derivant.The polyoxyalkylene polymers that their example includes the polymerization by ethylene oxide or propylene oxide and prepares, with the alkyl of polyoxyalkylene polymers and aryl ether (such as, molecular weight is methyl-polyisopropylene glycol ethers or the diphenyl ether of Polyethylene Glycol that molecular weight is 1000-1500 of 1000)；With their unitary and multi-carboxylate (the such as C of acetas, mixing₃-C₈The C of fatty acid ester and TEG₁₃Oxyacid diester.

Another kind of applicable synthetic lubricant fluid includes the ester of dicarboxylic acids (such as phthalic acid, succinic acid, alkyl succinic acid and alkenyl succinic acid, maleic acid, Azelaic Acid, suberic acid, decanedioic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl malonic acid, alkenyl malonic) and various alcohol (such as butanol, hexanol, lauryl alcohol, 2-Ethylhexyl Alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol).The instantiation of this kind of ester includes the 2-ethylhexyl diester of dibutyl adipate, decanedioic acid two (2-ethylhexyl) ester, the just own ester of fumaric acid two, di-n-octyl sebacate, diisooctyl azelate, two different decayl esters of azelaic acid, dioctyl phthalate, didecyl phthalate, decanedioic acid two (eicosyl) ester, linoleic acid dimer, and is reacted by the 2 ethyl hexanoic acid of TEG with 2 moles of the decanedioic acid of 1 mole and 2 moles and the complex ester that formed.

Can be used as the ester of artificial oil also to include by C₅-C₁₂Monocarboxylic acid and polyhydric alcohol and polyol ester such as neopentyl glycol, trimethylolpropane, tetramethylolmethane, dipentaerythritol and tripentaerythritol make those.

Oil such as many alkyl, polyaryl, many alkoxyls or many aryloxy group silicone oil and silicic acid ester oil based on silicon constitute another kind of useful syntholube；This oil includes tetraethyl orthosilicate, silicic acid four isopropyl ester, silicic acid four (2-ethylhexyl) ester, silicic acid four (4-methyl-2-ethylhexyl) ester, silicic acid four (to tert-butyl-phenyl) ester, six (4-methyl-2-ethylhexyl) disiloxane, poly-(methyl) siloxanes and poly-(aminomethyl phenyl) siloxanes.Other synthetic lubricant fluid includes liquid ester (such as the diethyl ester of tricresyl phosphate, trioctyl phosphate, decylphosphonic acid) and the polymerizing tetrahydrofuran of phosphoric acid.

Oil that is unpurified, refining and that re-refine can be used in the lubricant of the present invention.Unpurified oil be directly from natural or synthetic source obtain and without being further purified those of process.Such as, retorting operation the shale oil that directly obtains, the distillation oil directly obtained or the ester oil used by not processing further of directly obtaining of esterification process are unpurified oil.The similar unrefined oil of refined oil, is different in that described oil is processed further in one or more purification steps, improves one or more performances.These type of purification techniques many, if the extraction of distillation, solvent extraction, acid or alkali, filtration and diafiltration are for well known by persons skilled in the art.Rerefined oils is obtained by the method similar with those methods for providing refined oil, but from use used oil.These rerefined oils are also known as reclaiming or reprocessed oils, and are often subjected to use the additional processing being intended to remove the technology of useless additive and oil decomposition product.

American Petroleum Institute (API) publication " EngineOilLicensingandCertificationSystem ", IndustryServiceDepartment, the 14th edition, in December, 1996, oil base stock is classified as follows by annex in December, 1,1998:

A) group i base oils material comprises less than the saturate of 90% and/or the sulfur more than 0.03%, and viscosity index (VI) is more than or equal to 80 and less than 120, uses the test method of regulation in following table.

B) ii oil base stock comprise more than or equal to 90% saturate and less than or equal to 0.03% sulfur and viscosity index (VI) more than or equal to 80 and less than 120, use the test method of regulation in following table.

C) Group III oil base stock comprises more than or equal to 90% saturate with less than or equal to 0.03% sulfur, and viscosity index (VI) is more than or equal to 120, uses the test method of regulation in following table.

D) group iv base oils material is Poly alpha Olefins (PAO) (PAO).

E) Group V oil base stock includes all other oil base stock being not included in I, II, III or IV group.

The analysis test method of oil base stock above-mentioned provides in the following table:

Performance	Test method
		Saturate	ASTM D 2007
Viscosity index (VI)	ASTM D 2270
		Sulfur	ASTM D 2622
	ASTM D 4294
			ASTM D 4927
	ASTM D 3120

Example as above-mentioned oil, it can be mentioned Group I and Group II oil.Furthermore, it is possible to mention in above-mentioned oil containing more than or equal to 90% saturate and less than or equal to those of 0.03% sulfur as the oil of lubricant viscosity, for instance ii, III, IV or V group.They also include the oil base stock derived from the hydrocarbon synthesized by Fischer-Tropsch process.In Fischer-Tropsch process, first produce the synthesis gas (or " syngas ") containing carbon monoxide and hydrogen, then use Fischer-Tropsch catalyst to change into hydrocarbon.In order to can serve as base oil, these hydrocarbon typically require and are processed further.Such as, they are passable, by method as known in the art, hydroisomerization；Hydrogenation cracking and hydroisomerization；Dewaxing；Or hydroisomerization and dewaxing.Synthesis gas can be such as made up by steam reformation of gas such as natural gas or other gaseous hydrocarbon, and now oil base stock is properly termed as gas to liquid (" GTL ") base oil；Or synthesis gas can be such as made up of the gasification of biomass, now oil base stock is properly termed as biomass to liquid (" BTL " or " BMTL ") base oil；Or synthesis gas can be such as made up of coal gasification, now oil base stock is properly termed as coal to liquid (" CTL ") base oil.

Preferably, the oil of the lubricant viscosity in the present invention contains 50 mass % or more described oil base stock.It can contain 60, for instance 70,80 or 90 mass % or more described oil base stock or their mixture.The oil of lubricant viscosity can be substantially all described oil base stock or their mixture.

It is likely to cater to the need but not necessarily, prepares one or more additive bag comprising additive or concentrate, thus additive can be simultaneously introduced in the oil of lubricant viscosity and form TPEO.

Final preparation as trunk-piston engine oil generally can contain 30, it is preferable that 10-28, more preferably the additive bag of 12-24 mass %, remainder is the oil of lubricant viscosity.Preferably, described trunk-piston engine oil can have 20-60, for instance the composition TBN (using ASTMD2896) of 30-55.Such as, it can be 40-55 or 35-50.

The handling rate (treatrate) of the additive being included in lubricant oil composite can such as at 1-2.5, it is preferable that 2-20, more preferably in the scope of 5-18 mass %.

Embodiment

It is illustrated by the following examples the present invention, but is not intended to the present invention.

Trunk-piston engine oil (TPEO)

Prepare one group of TPEO, be only in that including two kinds of TPEO, both TPEO differences a kind of containing nitrogenous ashless dispersant, another kind of without.Every kind of TPEO contains the mixture of the mixture of parlkaline calcium salicylate detersive, amine and phenol antioxidant and other common additive.They contain identical base oil and constitute remainder.Described dispersant is the product making polyisobutenyl succinic anhydride and tetren react, and provides the N of 91 mass ppm for TPEO.Polyisobutylene based moiety has the number-average molecular weight of 950.

Testing every kind of TPEO in this body oils oxidation test, wherein oil is polluted and experiences oxidizing condition 120 hours by 0.5%HFO (heavy oil).Test is DKA oxidation test (CECL-48-00), wherein evaluates BN and viscosity B coefficent.

In panel coker test, also test every kind of TPEO, will be described below:

Panel coker test

Lubricating oil can be degraded and stay in the engine surface of heat will affect the deposit of engine performance；Panel coker test is simulated typical condition and measures the tendency of oil this type of deposit of formation.Tested oil is splashed on the metallic plate of heat by making metal pectination splasher equipment rotate in the storage tank containing described oil.When experimental period terminates, measure deposit.

Being summarized as follows of test method:

By oil heating described in 225ml to 100 DEG C in oil bath.

The aluminium sheet of heat is arranged on above described oil bath with heeling condition, maintains the temperature of 320 DEG C.

Sputter described oily 15 seconds facing to this plate, then do not sputter 45 seconds.

The circulation continuous of this interval sputtering 1 hour.

Weigh this sheet material calculate deposit, gram (g).

Green oil (without HFO) and adulterated oil (containing 2.5%HFO) are tested.Grade based on 1-10 represents result, and its intermediate value more low instruction deposit performance is more poor.

Result being tabulated below, the embodiment without dispersant is called " Ref ", and the embodiment containing dispersant is called " Inv ".

Result shows, the embodiment of the present invention (Inv) containing dispersant, compared with comparative example (Ref), not only shows the less minimizing of BN aspect but also show the less increase of KV100 aspect.Additionally, it is shown that when there is a small amount of dispersant, the deposit cleannes in panel coker test are improved dramatically, even if still such when TPEO is by the HFO pollution of 2.5%.

Claims

1. nitrogenous ashless dispersants agent addition agent is to provide 50-150, the amount of preferred 75-125 mass ppmN purposes in pot type piston marine lubricant compositions, described pot type piston marine lubricant compositions for being supplied fuel the medium speed compression ignition marine engine lubricated by said composition by heavy oil, described compositions has 20-60, the BN of preferred 30-55, described purposes is to reduce BN loss and reduce viscosity increase, without negatively affecting deposit performance.

2. nitrogenous ashless dispersants agent addition agent is to provide 50-150, the amount of preferred 75-125 mass ppmN purposes in pot type piston marine lubricant compositions, described pot type piston marine lubricant compositions for being supplied fuel the medium speed compression ignition marine engine lubricated by said composition by heavy oil, described compositions has 20-60, the BN of preferred 30-55, described purposes is, compared with the similar application when the amount of nitrogenous ashless dispersant is outside above-mentioned scope, reduce BN loss and reduce viscosity increase, without negatively affecting deposit performance.

3. the purposes of claim 1 or 2, wherein said compositions comprises the oil of major amount of lubricant viscosity, and the oil of this lubricant viscosity contains 50 mass % or more containing more than or equal to 90% saturate with less than or equal to the oil base stock of 0.03% sulfur.

4. the purposes of claim 1,2 or 3, wherein said compositions contains the hydroxy benzoic acid calcium salt detergent additives of parlkaline alkyl-replacement, for instance calcium salicylate.

5. the purposes any one of claim 1-4, wherein said compositions contains one or more and is selected from amine or phenol antioxidant and the common additive selected from ashless dispersant.

6. the purposes any one of claim 1-5, wherein said dispersant is the butanimide that alkyl replaces, for instance polyalkylenepolyamines.

7. the purposes of claim 6, wherein said alkyl is the polyisobutylene based moiety of number-average molecular weight 400-960.

8., for the pot type piston marine lubricant compositions of medium speed compression ignition marine engine, including nitrogenous ashless dispersants agent addition agent, its amount is for providing the N within the scope of 50-150 mass ppm in the composition.

9. the compositions of claim 8, wherein said scope is 75-125 mass ppmN.