Patent Publication Number: US-2020299603-A1

Title: Use of lubricating compositions to improve the cleanliness of a 4-stroke vehicle engine

Description:
The invention concerns the use of a lubricant composition to improve the cleanliness of a 4-stroke vehicle engine. More particularly, the invention concerns the use of an alcohol in a lubricant composition to improve the cleanliness of a 4-stroke vehicle engine. 
     Developments in engines and in the performance of engine lubricant compositions are inextricably linked. The more engine design becomes complex the higher the yield and optimisation of consumption, and the greater the demand placed on engine lubricant compositions for which performance must be improved. 
     Very high compression inside engines, higher piston temperatures in particular in the piston top segment, modern maintenance-free valve controls with hydraulic plungers, and very high temperatures in the engine space constantly place increasing demand on lubricants for modern engines. 
     The conditions of use of gasoline engines and diesel engines include both extremely short trips and long distances. The journeys travelled by 80% of motor vehicles in Western Europe cover less than 12 kilometres, whereas vehicles clock up annual distances of up to 300 000 km. 
     Oil change intervals are also most variable, being 5 000 km for some small diesel engines and may extend up to 100 000 km for diesel engines of modern commercial vehicles. 
     Lubricant compositions, and in particular lubricant compositions for motor vehicle engines, must therefore have improved properties and performance levels. 
     In addition, 4-stroke vehicle engines require high cold start properties. 
     One problem encountered when using known lubricant compositions concerns the degradation and coking of the oils or additives used. These degradation and coking phenomena may lead to clogging of the lubricated parts, in particular inside a vehicle engine. 
     It is therefore necessary to provide lubricant compositions allowing improved engine cleanliness in a 4-stroke vehicle engine. The improvement of engine cleanliness generally comprises reduced formation of deposits, in particular the formation of deposits at high temperatures such as varnish, paint, carbon or coke deposits. Such deposits may form on hot surfaces of engine parts such as the bottom of piston grooves, turbocharger shafts or air compressors. The substances contained in lubricant compositions may oxidize in contact with hot engine surfaces and generate the formation of insoluble products forming deposits. 
     These deposits may foul the engine and cause problems of wear, seizure, sticking of segments and problems related to turbocharger rotation for example. In general, additives of detergent type are used to improve the cleanliness of a 4-stroke vehicle engine. 
     Lubricant compositions are known from WO2015/179280 which comprise unsaturated fatty alcohols. However, this type of fatty alcohol solidifies at temperatures in the region of 10° C. and therefore does not allow satisfactory cold start properties to be obtained. 
     There is therefore a need for lubricant compositions providing good cold start properties. 
     These problems of fouling also concern the engines of hybrid or micro-hybrid vehicles equipped with the “Stop and Start” system. 
     In vehicle engines and in particular 4-stroke engines, deposits (engine fouling) are due to ageing of the lubricant. On the contrary, in 2-stroke marine engines, deposits are due to combustion of the mixture of lubricant and fuel on account of the specificity of 2-stroke marine engine operation (the term expendable lubrication system is used). 
     It is therefore necessary for vehicle engines, in particular motor vehicle and particularly 4-stroke engines to provide lubricant compositions able to withstand and especially undergo the least possible chemical degradation when an engine is in use, to limit ageing of the lubricant composition and hence limiting of deposits. This does not prove to be necessary for marine engines since the lubricant will always undergo combustion in the mixture with fuel. 
     It is therefore one objective of the present invention to provide compounds and a lubricant composition comprising these compounds to overcome all or some of the aforementioned shortcomings. 
     A further objective of the present invention is to provide a lubricant composition allowing the cleanliness of a 4-stroke vehicle engine to be improved, having a formulation that is easy to implement. 
     A further objective of the invention is to provide a lubricant composition allowing an improvement in the cleanliness of a 4-stroke vehicle engine and to reduce the content of detergent additives or dispersants. 
     A further objective of the present invention is to provide a lubricant composition allowing an improvement in the cleanliness of a 4-stroke vehicle engine whilst maintaining good cold start properties. 
     The subject of the invention is therefore the use of an alcohol of formula (I) 
       R—OH   (I)
 
     where R is a saturated, linear or branched alkyl group having 10 to 36 carbon atoms, preferably 12 to 36 carbon atoms, more preferably 12 to 24 carbon atoms, further preferably 12 to 18 carbon atoms
 
in a lubricant composition to improve the cleanliness of a 4-stroke vehicle engine.
 
     The improved engine cleanliness of the invention is considered to be an improvement in engine cleanliness compared with that obtained by a lubricant composition not containing the alcohol of the invention. 
     The applicant has surprisingly found that the presence of at least one alcohol of formula (I) in a lubricant composition allows improved cleanliness of a 4-stroke vehicle engine. The applicant has also found that the presence of at least one alcohol of formula (I) additionally allows good cold start properties of the lubricant to be maintained. 
     Advantageously, the lubricant compositions of the invention have good cleanliness improving properties when in use in an engine, thereby allowing the content of detergent additives to be reduced in said lubricant compositions. 
     Preferably, the alcohol is selected from among compounds of formula (I) where R is a saturated, branched alkyl group having 10 to 36 carbon atoms, preferably 12 to 36 carbon atoms, more preferably 12 to 24 carbon atoms, further preferably 12 to 18 carbon atoms. 
     The inventors have shown that an alcohol having an alkyl chain with more than 36 carbon atoms is solid. Consequently, on cold starts the composition is insufficiently fluid and is therefore unable to fulfil its role. Additionally, the inventors have shown that an alcohol having an alkyl chain with fewer than 10 carbon atoms is highly volatile. Therefore, when an engine is in use, the alcohol volatilises and is consequently unable to fulfil its role. The choice of alcohol is therefore of essential importance in the invention. 
     Preferably, the alcohol of formula (I) is of formula (Ia) 
       R 1 —C(R 2 )(H)—CH 2 —OH   (Ia)
 
     where R 1  and R 2  are saturated, linear or branched alkyls selected so that the compound of formula (Ia) comprises 10 to 36 carbon atoms, preferably 12 to 36 carbon atoms, more preferably 12 to 24 carbon atoms, further preferably 12 to 18 carbon atoms. 
     The alcohols of the invention are marketed by Ecogreen Oleochemicals under the trade names Ecorol 12/98®, Ecorol 14/98® and Ecorol 16/98®, or by Sasol under the trade Isofol®. 
     Advantageously, the alcohols of formula (I) where R is branched, or the alcohols of formula (Ia) which are branched alcohols, are liquid at temperatures lower than 0° C. (low melt point), allowing optimized use of the lubricant compositions of the invention in 4-stroke vehicle engines. The lubricant compositions comprising these alcohols have good cold start properties. 
     Preferably, the lubricant composition comprises from 0.1 to 10 weight %, preferably 0.1 to 4 weight %, more preferably 0.2 to 3 weight %, advantageously 0.3 to 2.5 weight % of alcohol relative to the total weight of the lubricant composition. 
     The present invention also concerns a lubricant composition for 4-stroke vehicle engine, comprising:
         at least one base oil; and   at least one alcohol of formula (I) such as defined above.       

     The present application also concerns the use of a lubricant composition of the invention to improve the cleanliness of a 4-stroke vehicle engine. 
     The invention also concerns a method for improving the cleanliness of a 4-stroke vehicle engine, said method comprising at least one step to contact a mechanical part of the machine with a lubricant composition such as defined above. 
     The percentages indicated in the present application correspond to weight percentages of active substance. 
     In general, the lubricant composition used in the invention may comprise any type of lubricant base oil whether mineral, synthetic or natural, animal or vegetable, known to persons skilled in the art. 
     The base oils used in the lubricant compositions of the invention can be oils of mineral or synthetic origin belonging to Groups 1 to V of the classes defined in the API classification (or equivalents in the ATIEL classification) (Table A), or mixtures thereof. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE A 
               
               
                   
                   
               
               
                   
                   
                   
                 Viscosity 
               
               
                   
                 Saturates 
                 Sulfur 
                 Index 
               
               
                   
                 content 
                 content 
                 (VI) 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 Group 1 
                  &lt;90% 
                 &gt;0.03% 
                 80 ≤ VI &lt; 120 
               
               
                 Mineral oils 
               
               
                 Group II 
                 ≥90% 
                 ≤0.03% 
                 80 ≤ VI &lt; 120 
               
               
                 Hydrocracked oils 
               
               
                 Group III 
                 ≥90% 
                 ≤0.03% 
                 ≥120 
               
               
                 Hydrocracked or 
               
               
                 hydroisomerized 
               
               
                 oils 
               
            
           
           
               
               
            
               
                 Group IV 
                 Polyalphaolefins (PAOs) 
               
               
                 Group V 
                 Esters and other bases not included in Groups 1 to IV 
               
               
                   
               
            
           
         
       
     
     The mineral base oils of the invention include all types of base oils obtained by atmospheric and vacuum distillation of crude oil, followed by refining operations such as solvent extraction, deasphalting, solvent dewaxing, hydrotreatment, hydrocracking, hydroisomerization and hydrofinishing. 
     Mixtures of synthetic and mineral oils can also be employed. 
     In general, there is no limit as to the use of different lubricating bases to produce the lubricant compositions of the invention, other than that they must have properties particularly of viscosity, viscosity index, sulfur content and oxidation resistance that are adapted for use in engines or for vehicle transmissions. 
     The base oils of the lubricant compositions used in the invention can also be selected from among synthetic oils such as some esters of carboxylic acids and alcohols, and from among polyalphaolefins. The polyalphaolefins used as base oils are obtained for example from monomers having 4 to 32 carbon atoms, e.g. from octene, decene or dodecene, and having a viscosity at 100° C. of between 1.5 and 15 mm 2 .s −1  in accordance with standard ASTM D445. Their molecular weight average is generally between 250 and 3 000 in accordance with standard ASTM D5296. 
     Preferably, the base oils of the present invention are selected from among the above base oils having an aromatic content of between 0 and 45%, preferably between 0 and 30%. 
     The aromatic content of oils is measured using the UV Burdett method. 
     Advantageously, the lubricant composition used in the invention comprises at least 50 weight % of base oils relative to the total weight of the composition. 
     More advantageously, the lubricant composition used in the invention comprises at least 60 weight %, even at least 70 weight % of base oils relative to the total weight of the composition. 
     Further advantageously, the lubricant composition used in the invention comprises from 60 to 99.5 weight % of base oils, preferably 70 to 99.5 weight % of base oils relative to the total weight of the composition. 
     Numerous additives can be employed for this lubricant composition used in the invention. 
     The preferred additives for the lubricant composition used in the invention are selected from among friction modifiers, detergents, anti-wear additives, extreme-pressure additives, viscosity index improvers, dispersants, antioxidants, pour point improvers, defoamers, thickeners and mixtures thereof. 
     Preferably, the lubricant composition used in the invention comprises at least one anti-wear additive, at least one extreme-pressure additive or mixtures thereof. 
     Anti-wear additives and extreme-pressure additives protect rubbing surfaces by forming a protective film adsorbed on these surfaces. 
     There is a wide variety of anti-wear additives. Preferably, for the lubricant composition of the invention the anti-wear additives are selected from among phospho-sulfurized additives such as metal alkylthiophosphates, in particular zinc alkylthiophosphates, and more specifically zinc dialkyldithiophosphates or ZnDTPs. The preferred compounds have the formula Zn((SP(S)(OR 3 )(OR 4 )) 2  where R 3  and R 4 , the same or different, are independently an alkyl group, preferably an alkyl group having 1 to 18 carbon atoms. 
     Amine phosphates are also anti-wear additives that can be used in the lubricant composition of the invention. However, the phosphorus contributed by these additives may act as poison for catalytic systems of motor vehicles since these additives generate ash. These effects can be minimised by partly substituting amine phosphates by additives that do not contain phosphorus such as polysulfides for example in particular sulfurized olefins. 
     Advantageously, the lubricant composition of the invention may comprise from 0.01 to 6 weight %, preferably 0.05 to 4 weight %, more preferably 0.1 to 2 weight % of anti-wear and extreme-pressure additives relative to the total weight of the lubricant composition. 
     Advantageously, the lubricant composition of the invention may comprise at least one friction modifying additive. The friction modifying additive can be selected from among a compound providing metal elements and an ash-free compound. Among the compounds providing metal elements, mention can be made of transition metal complexes such as Mo, Sb, Sn, Fe, Cu, Zn, the ligands of which may be hydrocarbon compounds comprising atoms of oxygen, nitrogen, sulfur or phosphorus. Ash-free friction modifying additives are generally or organic origin and can be selected from among the monoesters of fatty acids and polyols, alkoxylated amines, alkoxylated fatty amines, fatty epoxides, borate fatty epoxides; fatty amines or fatty acid glycerol esters. According to the invention, the fatty compounds comprise at least one hydrocarbon group having 10 to 24 carbon atoms. 
     Advantageously, the lubricant composition of the invention may comprise 0.01 to 2 weight %, or 0.01 to 5 weight %, preferably 0.1 to 1.5 weight % or 0.1 to 2 weight % of friction modifying additive relative to the total weight of the lubricant composition. 
     Advantageously, the lubricant composition of the invention may comprise at least one antioxidant additive. 
     An antioxidant additive generally allows delayed degradation of the lubricant composition in use. This degradation may notably translate as the formation of deposits, as the presence of sludge or as an increase in viscosity of the lubricant composition. 
     Antioxidant additives particularly act as radical inhibitors or hydroperoxide decomposers. Among the antioxidant additives frequently employed, mention can be made of antioxidant additives of phenolic type, antioxidant additives of amino type, phosphor-sulfurized antioxidant additives. Some of these antioxidant additives e.g. phospho-sulfurized antioxidant additives may generate ash. Phenolic antioxidant additives may be ash-free or may be in the form of neutral or basic metal salts. Antioxidant additives can be selected in particular from among sterically hindered phenols, sterically hindered phenol esters and sterically hindered phenols comprising a thioether bridge, diphenylamines, diphenylamines substituted by at least one C 1 -C 12  alkyl group, N,N′-dialkyl-aryl-diamines, and mixtures thereof. 
     Preferably, according to the invention, the sterically hindered phenols are selected from among compounds comprising a phenol group in which at least one vicinal carbon of the carbon carrying the alcohol function is substituted by at least one C 1 -C 10  alkyl group, preferably a C 1 -C 6  alkyl group, preferably a C 4  alkyl group, preferably by the tert-butyl group. 
     Amine compounds are another class of antioxidant additives that can be used, optionally in combination with phenolic antioxidant additives. Examples of amino compounds are the aromatic amines e.g. the aromatic amines of formula NR 5 R 6 R 7  where R 5  is an aliphatic group or aromatic group, optionally substituted, R 6  is an aromatic group, optionally substituted, R 7  is a hydrogen atom, an alkyl group, an aryl group or group of formula R 8 S(O) z R 9  where R 8  is an alkylene group or alkenylene group, R 9  is an alkyl group, an alkenyl group or aryl group and z is 0, 1 or 2. 
     Sulfurized alkyl phenols or the alkali or alkaline-earth metal salts thereof can also be used as antioxidant additives. 
     Another class of antioxidant additives is that of copper compounds e.g. copper thio- or dithio-phosphates, copper and carboxylic acid salts, copper dithiocarbamates, sulfonates, phenates and acetylacetonates. Copper I and II salts, the salts of succinic acid or anhydride can also be used. 
     The lubricant composition of the invention may contain any type of antioxidant additives known to persons skilled in the art. 
     Advantageously, the lubricant composition comprises at least one ash-free antioxidant additive. 
     Also advantageously, the lubricant composition of the invention comprises 0.5 to 2% by weight of at least one antioxidant additive relative to the total weight of the composition. 
     The lubricant composition of the invention may also comprise at least one detergent additive. 
     Detergent additives generally allow a reduction in the formation of deposits on the surface of metal parts by dissolving secondary oxidation and combustion products. 
     The detergent additives that can be used in the lubricant composition of the invention are generally known to skilled persons. The detergent additives can be anionic compounds comprising a long lipophilic hydrocarbon chain and hydrophilic head. The associated cation may be a metal cation of an alkali or alkaline-earth metal. 
     The detergent additives are preferably selected from among the salts of alkali metals or alkaline-earth metals of carboxylic acids, sulfonates, salicylates, naphthenates and phenate salts. The alkali or alkaline-earth metals are preferably calcium, magnesium, sodium or barium. 
     These metal salts generally comprise the metal in stoichiometric amount or in excess i.e. an amount greater than the stoichiometric amount. They are then overbased detergent additives; the excess metal imparting the overbased nature to the detergent additive is then generally in the form of an oil-insoluble metal salt e.g. a carbonate, hydroxide, an oxalate, acetate, glutamate, preferably a carbonate. 
     Advantageously, the lubricant composition of the invention may comprise from 0.5 to 4 weight % of detergent additive relative to the total weight of the lubricant composition. 
     Also advantageously, the lubricant composition of the invention may also comprise at least one pour point depressant additive. 
     By slowing the formation of paraffin crystals, pour point depressants generally improve the behaviour of the lubricant composition of the invention under cold temperatures. 
     As examples of pour point depressant additives, mention can be made of alkyl polymethacrylates, polyacrylates, polyarylamides, polyalkylphenols, polyalkylnaphthalenes, alkylated polystyrenes. 
     Advantageously the lubricant composition of the invention may also comprise at least one dispersant. 
     The dispersant can be selected from among Mannich bases, succinimides and derivatives thereof. 
     Also advantageously, the lubricant composition of the invention may comprise from 0.2 to 10% by weight of dispersant relative to the total weight of the lubricant composition 
     The lubricant composition of the present invention may also comprise at least one additive improving the viscosity index. As examples of viscosity index improvers mention can be made of polymer esters, homopolymers or copolymers, hydrogenated or non-hydrogenated, styrene, butadiene and isoprene, polyacrylates, polymethacrylates (PMAs) or olefin copolymers in particular ethylene/propylene copolymers. 
     The lubricant composition of the invention can be in different forms. In particular, the lubricant composition of the invention can be an anhydrous composition. 
     Preferably, this lubricant composition is not an emulsion. 
     The above-defined lubricant composition is used to improve the cleanliness of a 4-stroke vehicle engine. 
     The lubricant composition for 4-stroke vehicle is preferably characterized by a BN lower than 15, preferably lower than 10. BN is determined in accordance with standard ASTM D-2896. 
     Preferably, contrary to lubricants for marine engines which contain at least 5 weight % of detergent, the lubricants for vehicle engine generally comprise little detergent. 
     By vehicle engine according to the invention it is more particularly meant vehicle engines such as:
         engines of motor vehicles including gasoline engines and diesel engines, but also engines powered by gas and gasoline (dual-fuel gas/gasoline engines), engines powered by gas and diesel (dual-fuel gas/diesel engines) and engines powered by gasoline and diesel;   heavy vehicle engines and more specifically gas-operated heavy vehicle engines,   engines of hybrid or micro-hybrid vehicles equipped with a «Stop and Start” system.       

    
    
     
         FIG. 1 : Photo of piston underside after engine testing with a comparative composition (CC1). 
         FIG. 2 : Photo of piston underside after engine testing with a composition of the invention (CI8). 
     
    
    
     The different aspects of the invention can be illustrated by the following nonlimiting examples: 
     EXAMPLE 1 
     Lubricant Compositions of the Invention 
     The different components of the reference lubricant composition Cref1 were mixed according to the type and amounts given in Table 1. 
     
       
         
           
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Cref 1 
               
               
                   
                 (weight %) 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                 Gr III base oil (kinematic viscosity at 100° C. measured 
                 33.9 
               
               
                 as per standard ASTM D-556 = 4 mm 2 /s) 
               
               
                 Gr III base oil (kinematic viscosity at 100° C. measured 
                 20.6 
               
               
                 as per standard ASTM D-556 = 7 mm 2 /s) 
               
               
                 PAO-type base oil (kinematic viscosity at 100° C. 
                 30.0 
               
               
                 measured as per standard ASTM D-556 = 4 mm 2 /s) 
               
               
                 Viscosity index improver (olefin copolymer) 
                 5.5 
               
               
                 Pour point depressant (polymethacrylate) 
                 0.3 
               
               
                 Friction modifier (organomolybdenum compound) 
                 0.5 
               
               
                 Detergent (calcium sulfonate) 
                 0.5 
               
               
                 Additive package comprising a dispersant of 
                 8.7 
               
               
                 succinimide type, amine antioxidant, phenolic 
               
               
                 antioxidant, anti-wear of zinc dithiophosphate type, 
               
               
                 detergent of overbased calcium sulfonate type, 
               
               
                 detergent of neutral calcium sulfonate type, a silicone 
               
               
                 defoamer) 
               
               
                   
               
            
           
         
       
     
     Lubricant compositions of the invention CI1, CI2, CI3, CI4, CI5, CI6, CI7 were then prepared as a function of the type and amounts (weight %) given in Table 2. 
     
       
         
           
               
               
               
               
               
               
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Cref 
                 CI1 
                 CI2 
                 CI3 
                 CI4 
                 CI5 
                 CI6 
                 CI7 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 Cref 
                 100 
                 98 
                 96 
                 94 
                 92 
                 98 
                 96 
                 98 
               
               
                 Lauryl 
                   
                 2 
                 4 
                 6 
                 8 
               
               
                 alcohol 1   
               
               
                 Myristyl 
                   
                   
                   
                   
                   
                 2 
                 4 
               
               
                 alcohol 2   
               
               
                 Cetyl 
                   
                   
                   
                   
                   
                   
                   
                 2 
               
               
                 alcohol 3   
               
               
                   
               
               
                   1 Ecorol 12/98 ® marketed by Ecogreen Oleochemicals 
               
               
                   2 Ecorol 14/98 ® marketed by Ecogreen Oleochemicals 
               
               
                   3 Ecorol 16/98 ® marketed by Ecogreen Oleochemicals 
               
            
           
         
       
     
     EXAMPLE 2 
     Evaluation of Improved Engine Cleanliness Properties of the Lubricant Compositions of the Invention CI1 to CI7, and of the Reference Lubricant Cref 
     This evaluation was performed via PCT method in accordance with standard GFC LU 029 T97 and allowed simulation of the engine cleanliness performance of a lubricant composition. 
     The results of this evaluation are given in Table 3; the higher the score, the better the performance of the lubricant composition in improving cleanliness. 
     
       
         
           
               
               
               
               
               
               
               
               
             
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                 Cref 
                 CI1 
                 CI2 
                 CI3 
                 CI4 
                 CI5 
                 CI6 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Score 
                 7.4 
                 8 
                 7.9 
                 7.9 
                 7.9 
                 7.8 
                 7.7 
               
               
                   
               
            
           
         
       
     
     The results show that the use of an alcohol of the invention in a lubricant composition improves engine cleanliness (lubricant compositions CI1 to CI6), compared with a reference lubricant composition not containing an alcohol of the invention (lubricant composition Cref). 
     EXAMPLE 3 
     Evaluation of Improved Engine Cleanliness Properties of a Lubricant Composition of the Invention CI8 and of a Comparative Lubricant Composition CC1 
     The different components of the lubricant composition of the invention CI8 and of the comparative lubricant composition CC1 were mixed as a function of the type and amounts given in Table 4. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 4 
               
               
                   
                   
               
               
                   
                 CI8 
                 CC1 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Gr III base oil (kinematic viscosity at 
                 62 
                 64 
               
               
                   
                 100° C. measured as per standard 
               
               
                   
                 ASTM D-556 = 4 mm 2 /s) 
               
               
                   
                 Gr III base oil (kinematic viscosity at 
                 15 
                 15 
               
               
                   
                 100° C. measured as per standard 
               
               
                   
                 ASTM D-556 = 6 mm 2 /s) 
               
               
                   
                 Viscosity index improver 
                 3.5 
                 3.5 
               
               
                   
                 (polymethacrylate) 
               
               
                   
                 Viscosity index improver 
                 2 
                 2 
               
               
                   
                 (Hydrogenated polyisoprene styrene 
               
               
                   
                 (HPIS)) 
               
               
                   
                 Pour point depressant additive 
                 0.2 
                 0.2 
               
               
                   
                 (polymethacrylate) 
               
               
                   
                 Friction modifier 
                 0.5 
                 0.5 
               
               
                   
                 (organomolybdenum compound) 
               
               
                   
                 Additive package comprising a 
                 14.8 
                 14.8 
               
               
                   
                 dispersant of succinimide type, 
               
               
                   
                 detergent of calcium sulfonate type, 
               
               
                   
                 detergent of calcium carbonate type 
               
               
                   
                 Lauryl alcohol  4   
                 2 
               
               
                   
                   
               
               
                   
                   4  Ecorol ®12/98 marketed by Ecogreen Oleochemicals 
               
            
           
         
       
     
     The engine cleanliness performance of the lubricant compositions CI8 and CC1 was evaluated with the following method. 
     Each lubricant composition (8 Kg) was evaluated using a cleanliness test for a vehicle diesel engine with common rail. The engine capacity was 1.4 L for 4 cylinders. Engine power was 80 kW. The test cycle length was 96 hours alternating idle speed and a speed of 4 000 rpm. The temperature of the lubricant composition was 145° C. and the water temperature of the cooling system was 100° C. No oil change and no topping-up of lubricant were performed during the test. EN 590 fuel was used. The test took place in two phases for a total time of 106 hours with a first rinsing and run-in phase for 10 hours followed by a second step with the evaluated composition (4 kg), and finally an endurance step lasting 96 hours with the evaluated composition (4 kg). 
     After this test, the engine parts were analysed and the 4 pistons evaluated in accordance with European standard CEC M02A78. For each piston the score was recorded and a mean of the total piston score for the 4 pistons was calculated. 
     The results obtained are grouped together in Table 5. 
     The regular passing of a reference oil showed that a difference of 4 points between two candidates is significant. 
     The higher the value of the mean score the better the improved cleanliness of the piston, and hence the better the performance of the lubricant composition in improving engine cleanliness. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 5 
               
               
                   
                   
               
               
                   
                 Evaluated 
                   
               
               
                   
                 composition 
                 Mean piston score after testing 
               
               
                   
                   
               
             
            
               
                   
                 CI8 
                 68.5 
               
               
                   
                 CC1 
                 61.6 
               
               
                   
                   
               
            
           
         
       
     
     The results confirm those of Example 2 regarding the improvement in engine cleanliness afforded by a lubricant composition comprising an alcohol of the invention (lubricant composition CI8), in comparison with a lubricant composition not containing an alcohol of the invention (lubricant composition CC1). 
     In addition, it is also shown in  FIGS. 1 and 2 , after this test, that the piston undersides are clean i.e. there was no deposit when composition CI8 was used ( FIG. 2 ), unlike composition CC1 for which fouling of the piston undersides was observed ( FIG. 1 ). 
     EXAMPLE 4 
     Evaluation of Improved Engine Cleanliness Properties of a Lubricant Composition of the Invention CI9, and of a Comparative Lubricant Composition CC2 
     The different components of the lubricant composition of the invention CI9 and of the comparative lubricant CC2 were mixed as a function of the type and amounts given in Table 6. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 6 
               
               
                   
                   
               
               
                   
                 CI9 
                 CC2 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Gr III base oil (kinematic viscosity at 
                 71.1 
                 72.1 
               
               
                   
                 100° C. measured as per standard 
               
               
                   
                 ASTM D-556 = 4 mm 2 /s) 
               
               
                   
                 Gr III base oil (kinematic viscosity at 
                 10.8 
                 10.8 
               
               
                   
                 100° C. measured as per standard 
               
               
                   
                 ASTM D-556 = 8 mm 2 /s) 
               
               
                   
                 Viscosity index improver 
                 5.7 
                 5.7 
               
               
                   
                 (polymethacrylate) 
               
               
                   
                 Pour point depressant additive 
                 0.2 
                 0.2 
               
               
                   
                 (polymethacrylate) 
               
               
                   
                 Friction modifier 
                 0.8 
                 0.8 
               
               
                   
                 (organomolybdenum compound) 
               
               
                   
                 Additive package comprising a 
                 10.4 
                 10.4 
               
               
                   
                 dispersant of succinimide type, 
               
               
                   
                 detergent of calcium sulfonate type, 
               
               
                   
                 detergent of calcium carbonate type 
               
               
                   
                 Lauryl aclcohol 5   
                 1 
               
               
                   
                   
               
               
                   
                   5 1-dodecanol marketed by Sigma Aldrich 
               
            
           
         
       
     
     The engine cleanliness performance of lubricant compositions CI9 and CC2 were evaluated with the Sequence IIIG method in accordance with standard ASTM D7320 under the following test conditions: 
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                 Parameters 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Engine speed 
                 3600 
                 rpm 
               
               
                   
                 Engine load 
                 250 
                 N-m 
               
               
                   
                 Oil temperature of oil filter 
                 150° 
                 C. 
               
               
                   
                 Outgoing temperature of coolant 
                 115° 
                 C. 
               
               
                   
                 Fuel pressure 
                 377.5 
                 kPa 
               
               
                   
                 Incoming air temperature 
                 35° 
                 C. 
               
               
                   
                 Incoming air pressure 
                 0.05 
                 kPa 
               
               
                   
                 Air dewpoint temperature 
                 16.1° 
                 C. 
               
               
                   
                 Exhaust counter-pressure 
                 6 
                 kPa 
               
               
                   
                 Coolant flow rate 
                 160 
                 L/min 
               
               
                   
                 Condenser coolant flow rate 
                 10 
                 L/min 
               
            
           
           
               
               
               
            
               
                   
                 Air/fuel ratio 
                 15.0:1 
               
            
           
           
               
               
               
               
            
               
                   
                 Temperature of condenser coolant 
                 40° 
                 C. 
               
               
                   
                   
               
            
           
         
       
     
     After this test, the engine parts were analysed and rated in the manner described in the procedure published in ASTM D7320. 
     The results of this test are given in Table 7 for compositions CI9 and CC2 respectively. The higher the score the better the performance of the lubricant composition in improving cleanliness. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 7 
               
               
                   
                   
               
               
                   
                 CC2 
                 CI9 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Mean of total score 
                 4.28 
                 4.76 
               
               
                   
                 Final result 
               
               
                   
                   
               
            
           
         
       
     
     The results show that the use of an alcohol of the invention in a lubricant composition allows an improvement in engine cleanliness (lubricant composition CI9) compared with a reference composition not containing an alcohol of the invention (lubricant composition CC2). 
     EXAMPLE 5 
     Study on Cold Start Properties 
     The compositions in Table 8 were tested for their cold start properties: 
     
       
         
           
               
               
               
               
               
             
               
                   
                 TABLE 8 
               
               
                   
                   
               
               
                   
                 CC3 
                 CI10 
                 CI11 
                 CI12 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Base oil 
                 74.1 
                 73.6 
                 73.1 
                 72.1 
               
               
                   
                 Additives 
                 11.3 
                 11.3 
                 11.3 
                 11.3 
               
               
                   
                 Viscosity index 
                 14.3 
                 14.3 
                 14.3 
                 14.3 
               
               
                   
                 improver 
               
               
                   
                 Pour point 
                 0.3 
                 0.3 
                 0.3 
                 0.3 
               
               
                   
                 depressant 
               
               
                   
                 2-Butyloctanol 6   
                 0 
                 0.5 
                 1 
                 2 
               
               
                   
                   
               
               
                   
                   6 ISOFOL C12 ® alcohol of formula (Ia) in C12. 
               
            
           
         
       
     
     The results obtained are given in Table 9. 
     
       
         
           
               
               
               
               
               
               
             
               
                   
                 TABLE 9 
               
               
                   
                   
               
               
                   
                 Standards 
                 CC3 
                 CI10 
                 CI11 
                 CI12 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 KV40 
                 ISO 3104 
                 93.67 
                 90.92 
                 88.91 
                 85.04 
               
               
                 (mm 2  · s −1 ) 
               
               
                 KV100 
                 ISO3104 
                 14.18 
                 13.94 
                 13.7 
                 13.26 
               
               
                 (mm 2  · s −1 ) 
               
               
                 VI 
                 ISO2909 
                 156 
                 157 
                 157 
                 157 
               
               
                 CCS at 
                 ASTM 
                 5390 
                 5280 
                 5150 
                 4930 
               
               
                 −35° C. 
                 D5293 
               
               
                 (mPa · s) 
               
               
                 MRV (cP) 
                 ASTM 
                 24060 
                 22630 
                 21580 
                 20460 
               
               
                   
                 D4684 
               
               
                   
               
            
           
         
       
     
     Specifically, in the Mini Rotary Viscometer (MRV) test, the viscosity of the compositions of the invention was lower than in the comparative composition. This MRV test allows simulation of engine lubrication conditions on cold starts and in particular the pumpability of the lubricant on cold starts. The compositions of the invention therefore have better cold pumpability than compositions not containing a fatty alcohol. 
     Also specifically, in the Cold Cranking Simulator (CCS) test, the fluidity of the compositions of the invention was lower than in the comparative composition. This CCS test allows simulation of engine lubrication conditions on cold starts, and in particular the fluidity of the lubricant on cold starts allowing ignition of the engine. The compositions of the invention therefore have better cold start fluidity than the compositions not containing a fatty alcohol. 
     These results show that the branched alcohols of the invention afford improved cold start properties of the lubricant.