Lubricating composition for a four-stroke engine with low ash content

Abstract

The present disclosure relates to a lubricating composition for a four-stroke engine, with low ash content including: a) one or more base oils selected from oils of Groups I-IV, preferentially from oils of Group III or IV from the API classification, b) at least one compound (b) selected from the group of heavy PAOs with a kinematic viscosity at 100° C. comprised between 75 and 3,000 cSt, optionally mixed with one or more compounds selected from the group of polymeric compounds of the polyisobutene (PIB) type, or one of their mixtures, and c) at least one ester of formula R(OH) m (COOR′(OH) p ) n wherein m is an integer from 0 to 8, preferably from 1 to 4, n is an integer from 1 to 8, preferably from 1 to 4 and p is an integer from 0 to 8, preferably from 1 to 4 and wherein the sum p+m is strictly greater than zero, R and R′ represent independently of each other a saturated or unsaturated, linear or branched hydrocarbon group, optionally substituted with one or more aromatic groups and including from 1 to 30 carbon atoms, and borated derivatives thereof; the composition having a sulfated ash content less than or equal to 0.5%, as measured according to the ASTM D874 standard, a phosphorus content less than or equal to 500 ppm, as measured according to the ASTM D5185 standard, and a sulfur content less than 0.2%, as measured according to the ASTM D5185 standard. The composition has good detergency properties, the use of which promotes fuel savings.

1 . A lubricating composition with low ash content for four-stroke engines comprising:
 a) one or more base oils selected from the oils of Groups I-V, preferentially from oils of Group III or IV from the API classification;   b) at least one compound (b) selected from the group of heavy PAOs with a kinematic viscosity at 100° C. comprised between 75 and 3,000 cSt, in an optional mixture with one or more compounds selected from the group of polymeric compounds of the polyisobutene (PIB) type; and   c) at least one ester of formula R(OH) m  (COOR′(OH) p ) n  wherein m is an integer from 0 to 8, n is an integer from 1 to 8, and p is an integer from 0 to 8, and wherein the sum p+m is strictly greater than zero, R and R′ represent independently of each other a saturated or unsaturated, linear or branched hydrocarbon group, optionally substituted with one or more aromatic groups, and including from 1 to 30 carbon atoms, and borated derivatives thereof;   
       the composition having a sulfated ash content less than or equal to 0.5%, as measured according to the ASTM D874 standard, a phosphorus content less than or equal to 500 ppm as measured according to the ASTM D5185 standard, and a sulfur content less than 0.2% as measured according to the ASTM D5185 standard. 
     
     
         2 . The composition according to  claim 1  wherein the ester (c) contains at least one free hydroxyl OH group belonging to the group R, the OH group being located in the alpha, beta or gamma position with respect to the carbon of the CO function of an ester function on which the group R is bound, and/or contains at least one free hydroxyl OH group belonging to the group R′, said OH group being located in the beta, gamma or delta position with respect to the oxygen of the COO group of an ester function on which the group R′ is bound. 
     
     
         3 . The composition according to  claim 1 , wherein the group R′ of the ester (c) represents a C 1 -C 10  group. 
     
     
         4 . The composition according to  claim 3 , wherein p is strictly greater than zero and the group R of the ester (c) represents a C 8 -C 25  group. 
     
     
         5 . The composition according to  claim 4 , wherein at least one ester (c) is selected from glycerol monoesters or diesters, preferentially selected from glycerol mono-oleate, glycerol stearate or isostearate and borated derivatives thereof. 
     
     
         6 . The composition according to  claim 3 , wherein n is an integer comprised between 1 and 4 and the R group of the ester (c) represents a C 1 -C 5  group. 
     
     
         7 . The composition according to  claim 6 , wherein at least one ester (c) is selected from citrates, tartrates, malates, lactates, mandelates, glycolates, hydroxypropionates, hydroxyglutarates or borated derivatives thereof. 
     
     
         8 . The composition according to  claim 1 , leading to minimum fuel savings as measured on a M111FE test, of at least 2.5% and meeting the ACEA-C1 specifications defined by the European Automobile Manufacturers' Association. 
     
     
         9 . The composition according to  claim 1 , having a kinematic viscosity at 100° C., as measured by the ASTM D445 standard, comprised between 5.6 and 16.3 cSt. 
     
     
         10 . The composition according to  claim 1 , with a 5W30 grade according to the SAEJ300 classification. 
     
     
         11 . The composition according to  claim 1 , with a viscosity index VI larger than or equal to 130. 
     
     
         12 . The composition according to  claim 1 , wherein the base oil or the mixture of base oils (a) amounts to at least 70% by weight of the composition. 
     
     
         13 . The composition according to  claim 1 , wherein the base oil or the mixture of base oils (a) comprises:
 at least 60% by weight, based on the total lubricant weight, of one or more base oils of Group III; and   at least 10% by weight, based on the total lubricant weight, of one or more base oils of Group IV.   
     
     
         14 . The composition according to  claim 1 , comprising a compound (b) selected from the group of heavy PAOs, and a compound (b) selected from the group of polymeric compounds of the FIB type. 
     
     
         15 . The composition according to  claim 1 , comprising 0.1 to 6% of at least one compound (b) and from 0.1 to 2.5% of at least one compound (c). 
     
     
         16 . The composition according to  claim 1 , comprising at least one anti-wear compound of the zinc dithiophosphate type, optionally combined with an amine phosphate. 
     
     
         17 . The composition according to  claim 1 , comprising at least one anti-wear compound of the zinc dithiophosphate type in an amount less than or equal to 1%. 
     
     
         18 . The composition according to  claim 1 , free of any amine phosphate type additive. 
     
     
         19 . The composition according to  claim 1 , free of any molybdenum friction modifier additive. 
     
     
         20 . The composition according to  claim 1 , comprising at least one antioxidant compound, preferably ashless, preferentially of the phenolic or aminated type. 
     
     
         21 . The composition according to  claim 1 , comprising from 0.01 to 5% of one or more antioxidant additives. 
     
     
         22 . The composition according to  claim 1 , with a BN, determined according to the ASTM D-2896 standard, less than or equal to 8 milligrams of potash per gram of lubricant. 
     
     
         23 . The composition according to  claim 1 , comprising between 0 and 3% of a VI-enhancing polymer selected from polymeric esters, olefin copolymers (OCP), homopolymers or copolymers of styrene, butadiene or isoprene, polymethacrylates (PMAs). 
     
     
         24 . A method for making a lubricating composition according to  claim 1 , by diluting a package of additives comprising at least one compound (b) and at least one compound (c), in a base oil or a mixture of oil bases (a) and wherein a VI-enhancing polymer is optionally added. 
     
     
         25 . The making method according to  claim 24 , wherein the additive package is diluted so as to amount to 10-30% by weight of the lubricating composition, and wherein the VI-enhancing polymer amounts to 0-3% by weight of the lubricating composition. 
     
     
         26 . A package of additives for a four-stroke engine lubricant with a sulfated ash content less than or equal to 0.5%, as measured according to the ASTM D874 standard, a phosphorus content less than or equal to 500 ppm, as measured according to ASTM D5185, and a sulfur content less than 0.2%, as measured according to the ASTM D5185 standard, the package comprising:
 at least one compound (b), a heavy PAO optionally mixed with a PIB;   at least one hydroxylated ester (c); and   optionally anti-wear and extreme pressure additives, friction modifiers, detergents, antioxidants, detergents either overbased or not, flow point lowering additives, dispersants, anti-foam additives, thickeners, polymers enhancing the viscosity index.   
     
     
         27 . The additive package according to  claim 26  comprising:
 0.5-30% by weight of at least one compound (b), a heavy PAO optionally mixed with PIB; and 
 0.5-15% by weight of at least one hydroxylated ester (c). 
 
     
     
         28 . The use of a composition according to  claim 1 , as a lubricant for a four-stroke engine. 
     
     
         29 . The use of at least one ester of formula R(OH) m  (COOR′(OH) p ) n  wherein m is an integer from 0 to 8, n is an integer from 1 to 8, and p is an integer from 0 to 8, and wherein the sum p+m is strictly greater than zero, R and R′ represent independently of each other a saturated or unsaturated linear or branched hydrocarbon group, optionally substituted with one or more aromatic groups, and including 1 to 30 carbon atoms, and borated derivatives thereof, as a friction modifying agent for the preparation of a lubricating composition for a four-stroke engine with a sulfated ash content less than or equal to 0.5%, as measured according to the ASTM D874 standard, a phosphorus content less than or equal to 500 ppm, as measured according to ASTM D5185, and a sulfur content less than or equal to 0.2%, as measured according to the ASTM D5185 standard.