Ultra-fluid lubricating composition

Abstract

In the field of lubricating compositions for motor vehicles, there is disclosed a lubricating composition of a grade according to the SAEJ300 classification defined by the formula (X) W (Y) wherein X represents 0 or 5 and Y represents an integer ranging from 4 to 20. This lubricating composition includes at least one polyalphaolefinic oil (PAO), from 10 to 80% by weight of the composition of at least one oil of group V and at least one comb polymer. Also isclosed is the use of this lubricating composition for improving the Fuel Eco (FE) of a lubricant or for reducing the fuel consumption of an engine, in particular a motor vehicle engine, notably a motor of a hybrid vehicle.

Claims

1. A lubricant composition of a grade according to the SAEJ300 classification defined by the formula (I)
(X) W (Y) (I) wherein X represents 0 or 5; Y represents an integer ranging from 4 to 20; and comprising (a) at least one polyalphaolefinic oil (PAO) for which the kinematic viscosity measured at 100 C according to the ASTM D445 standard ranges from 1.5 to 8 mm.sup.2.s.sup.1; (b) from 10 to 80% by weight of the composition of at least one oil of group V for which the kinematic viscosity measured at 100 C. according to the ASTM D445 standard ranges from 1.5 to 8 mm.sup.2.s.sup.1; (c) at least one comb polymer for which the three pendant chains comprise at least 50 carbon atoms and selected from among the copolymers of at least one polyolefin and of at least one poly(alkyl)methacrylate; the copolymers of at least one polyolefin and of at least one poly(alkyl)acrylate; wherein the at least one oil of group V is selected from among a monoester of formula (B1); ##STR00017## wherein R.sup.1 represents a linear or branched, saturated or unsaturated hydrocarbon group, comprising from 14 to 24 carbon atoms; R.sup.2 represents a linear or branched, saturated or unsaturated hydrocarbon group, comprising from 2 to 18 carbon atoms; and a polyalkylene-glycol (PAG) of formula (B2) ##STR00018## wherein R3 represents a linear or branched C1-C30-alkyl group; m and n represent independently an average number ranging from 1 to 5; and wherein the weight ratio (a/b) between the polyalphaolefinic oil (PAO) (a) and the oil of group V (b) ranges from 0.1 to 4.

2. The lubricant composition according to claim 1 of a grade according to the SAEJ300 classification selected from among OW4, OW8, OW12, OW16, OW20, 5W4, 5W8, 5W12, 5W16, 5W20.

3. The lubricant composition according to claim 1, for which the kinematic viscosity measured at 40 C. according to the ASTM D445 standard ranges from 12 to 30 mm.sup.2.s.sup.1.

4. The lubricant composition according to claim 1 for which the kinematic viscosity of the PAO, measured at 100 C. according to the ASTM D445 standard, ranges from 1.5 to 6 mm.sup.2.s.sup.1.

5. The lubricant composition according to claim 1 for which the average molecular mass by weight of the PAO ranges from 50 to 500 Da.

6. The lubricant composition according to claim 1 comprising from 20 to 80% by weight of the oil composition of group V.

7. The lubricant composition according to claim 1, for which the comb polymer for which the pendant chains are obtained by polymerization or by copolymerization of olefins.

8. The lubricant composition according to claim 1, for which the comb polymer is prepared by copolymerization of an olefinic monomer of formula (C2) ##STR00019## wherein Q.sup.3 represents a linear or branched C.sub.2-C.sub.8-alkyl group; a C.sub.3-C.sub.8-cycloalkyl group; a C.sub.6-C.sub.10-aryl group; Q.sup.4 represents a hydrogen atom or a methyl group; L.sup.1 represents a residue of 1,4 addition of butadiene; a residue of 1,4 addition of butadiene substituted with at least one C.sub.1-C.sub.6-alkyl group; a residue of vinyl addition of styrene; a residue of vinyl addition of styrene substituted with at least one C.sub.1-C.sub.6-alkyl group; L.sup.2 represents a residue of vinyl addition of butadiene; a residue of vinyl addition of butadiene substituted with a C.sub.1-C.sub.6-alkyl group; a residue of vinyl addition of styrene; a residue of vinyl addition of styrene substituted with at least one C.sub.1-C.sub.6-alkyl group; k and j represent independently 0 or an integer ranging from 1 to 3,000 and the sum (k+j) is equal to an integer ranging from 7 to 3,000; and of an alkyl-acrylic ester monomer or alkyl-methacrylic ester of formula (C3) ##STR00020## wherein Q.sup.5 represents a hydrogen atom or a methyl group; Q.sup.6 represents a linear or branched C.sub.1-C.sub.26-alkyl group.

9. The lubricant composition according to claim 1 for which the comb polymer is prepared by copolymerization of an olefinic monomer of formula (C4) ##STR00021## wherein Q.sup.7 represents a C.sub.1-C.sub.6-alkyl group; a C.sub.6-aryl group; Q.sup.8 represents a hydrogen atom or a methyl group; Q.sup.9, Q.sup.10 and Q.sup.11 represent independently a hydrogen atom or a C.sub.1-C.sub.18-alkyl group; x, y and z represent independently 0 or an integer ranging from 1 to 3,000 and the sum (x+y+z) is equal to an integer ranging from 7 to 3,000; and of a alkyl-acrylic ester monomer or methacrylic- alkyl ester of formula (C3) ##STR00022## wherein Q.sup.5 represents a hydrogen atom or a methyl group; Q.sup.6 represents a linear or branched C.sub.1-C.sub.26-alkyl group.

10. The lubricant composition according to claim 1, for which the VI is greater than 220.

11. A method for the lubrication of a vehicle engine or for improving the lubrication of a vehicle engine during an urban cycle according to the European cycle NEDC; or during an urban cycle according to the European cycle WLTP; or during a cold cycle according to the European cycle ECE; comprising a step of applying the lubricant composition according to claim 1 to said vehicle engine.

12. The method according to claim 11 for lubricating an engine of a hybrid vehicle.

13. A method for improving the Fuel Eco (FE) of a lubricant or for reducing the fuel consumption of an engine, comprising a step of adding the lubricant composition according to claim 1 into said lubricant, or a step of applying the lubricant composition to said engine.

Description

EXAMPLE 1

Preparation of Lubricant Compositions According to the Invention

(1) The different components of the lubricant compositions according to the invention are mixed depending on the nature and on the amounts of products shown in table 1.

(2) TABLE-US-00002 TABLE 1 Lubricant compositions according to the invention (% by weight) CL1 CL2 CL3 CL4 PAO - (Durasyn 164 Ineos) 64.2 44.2 24.2 44.2 Oil of Group V - Monoester (Priolube 1414 20 40 60 0 Croda) Oil of Group V - PAG of formula (B2) with 0 0 0 40 R.sup.3 = C.sub.12H.sub.25, m = 2.45 and n = 1.97 Comb polymer - Comb polymethacrylate 6.2 6.2 6.2 6.2 (Viscoplex 3-200 Evonik) Packet of additives Ca sulfonates, anti- 8.6 8.6 8.6 8.6 oxidant agents of the alkylated and hindered phenol diphenylamine type, ZnDTP secondary, dispersant of the bisuccinimide type Anti-friction agent MoDTC (Sakuralube 525 1.0 1.0 1.0 1.0 Adeka)

(3) The characteristics of these lubricant compositions according to the invention are shown in table 2.

(4) TABLE-US-00003 TABLE 2 Lubricant composition CL1 CL2 CL3 CL4 SAEJ300 Grade 0W12 0W12 0W12 0W16 calculated KV 130 (mm.sup.2 .Math. s.sup.1) 4.62 4.32 4.63 4.79 KV100 - ISO 3104 (mm.sup.2 .Math. s.sup.1) 6.950 6.43 6.995 7.191 KV40 - ISO3104 (mm.sup.2 .Math. s.sup.1) 23.31 20.92 23.79 24.45 VI - ISO2909 284 296 283 287 HTHS at 150 C. - CEC L-036 2.24 2.17 2.15 2.83 (mPa .Math. s) CCS at 35 C. - ASTM D5293 / 839 / 1,415 (mPa .Math. s)

EXAMPLE 2

Preparation of Comparative Lubricant Compositions

(5) The different components of the comparative lubricant compositions according to the nature and to the amounts of the products presented in table 3.

(6) TABLE-US-00004 TABLE 3 Comparative composition (% by weight) CC1 CC2 PAO - (Durasyn 164 Ineos) 44.2 84.2 Group V Oil- Monoester (Priolube 1414 Croda) 40 0 Polymer - Linear Polymethacrylate (Viscoplex 6- 6.2 0 054 Evonik) Comb polymer - Comb Polymethacrylate 0 6.2 (Viscoplex 3-200 Evonik) Packet of additves - Ca sulfonates, antioxidant 8.6 8.6 agents of the alkylated and hindered phenol and diphenylamine type, secondary ZnDTP, dispersant of the bisuccinimide type Anti-friction agent MoDTC (Sakuralube 525 Adeka) 1.0 1.0

(7) The first comparative lubricant composition (CC1) does not comprise any comb polymethacrylate but a linear polymethacrylate. The second comparative lubricant composition (CC2) does not comprise any oil of group V but only the oil of group IV. The characteristics of these comparative lubricant compositions are shown in table 4.

(8) TABLE-US-00005 TABLE 4 Comparative lubricant composition CC1 CC2 SAEJ300 Grade 0W12 0W16 calculated KV 130 (mm.sup.2 .Math. s.sup.1) 3.84 4.03 KV100 - ISO 3104 (mm.sup.2 .Math. s.sup.1) 5.970 6.358 KV40 - ISO3104 (mm.sup.2 .Math. s.sup.1) 23.08 26.19 VI - ISO2909 225 210 HTHS at 150 C. - CEC L-036 2.14 2.30 (mPa .Math. s) CCS at 35 C. - ASTM D5293 968 2,268 (mPa .Math. s)

EXAMPLE 3

Evaluation of the Fuel Saving Performances of the Lubricant Compositions According to the Invention (CL2 and CL4) and of the Comparative Lubricant Composition (CC1)

(9) During several tests according to the conditions described in the examples of WO 2012-025901, the fuel consumption during the lubrication by means of the lubricant composition according to the invention is compared with the fuel consumption during the use of a reference lubricant composition (base oil and packet of additives similar to the packet of additives of the composition according to the inventionSAEJ300 grade 5W30). The fuel consumption gains are evaluated by taking as a reference the fuel consumptions resulting from the use of this reference lubricant composition. The obtained results are shown in table 5.

(10) TABLE-US-00006 TABLE 5 Gain obtained by means of the lubricant composition (%) CL2 CL4 CC1 Full NEDC cycle 4.89 4.01 4.73 NEDC cycle cold ECE phase 12.84 10.34 11.11 NEDC cycle mixed urban cycle phase 7.48 5.58 6.03

(11) It is seen that the lubricant compositions CL2 and CL4 according to the invention give the possibility of obtaining very significant fuel consumption gains. Thus, the lubricant composition according to the invention CL2 allows gains larger than those obtained with the comparative lubricant composition CC1 which does not comprise any comb polymethacrylate. Moreover, the lubricant composition according to the invention CL4 comprises an oil of group V of the PAG type also gives the possibility of significant gains.

(12) More particularly it is seen that these lubricant compositions according to the invention give the possibility of highly significant fuel savings gains on the engine cycle at a low temperature and at a low engine speed, which demonstrates the benefit of these lubricant compositions according to the invention for obtaining even more significant fuel savings under urban conditions.

EXAMPLE 4

Evaluation of the Performances of the Traction Coefficient of the Lubricant Compositions According to the Invention (CL1, CL2 and CL3) and of a Comparative Lubricant Composition (CC2)

(13) The traction coefficient of the lubricant compositions is evaluated and the obtained results are shown in table 6.

(14) TABLE-US-00007 TABLE 6 Lubricant composition CL1 CL2 CL3 CC2 traction coefficient (MTM: T = 40 C., V.sub.e = 0.019 0.018 0.016 0.023 1 m..sup.1, SRR = 20% of load = 25N)

(15) The lubricant compositions according to the invention therefore have very good traction coefficients. These results confirm that the lubricant compositions according to the invention give the possibility of reducing the friction coefficient and therefore to improve the fuel savings gain as compared with a comparative lubricant composition comprising a PAO and a comb polymer according to the invention but not comprising any oil of group V according to the invention, and this with different oil contents of group V.

EXAMPLE 5

Evaluation of the Engine Cleanliness Performances of the Lubricant Compositions According to the Invention (CL1, CL2, CL3 and CL4) and of a Comparative Lubricant Composition (CC2)

(16) The engine cleanliness properties are evaluated by the TEOST MHT test according to the standard ASTM D7097 and the obtained results are shown in table 7 and expressed in milligrams. The maximum acceptable value, notably for most automobile manufacturers, is equal to 35 mg according to the ILSAC classification for an oil of grade 0Wxx.

(17) TABLE-US-00008 TABLE 7 Lubricant composition CL1 CL2 CL3 CL4 CC2 Deposit on the Teost MHT rod - 12.2 11.9 22.7 10.7 7.6 ASTM D7097 (mg)

(18) The lubricant compositions according to the invention therefore give the possibility of retaining good engine cleanliness, or even to improve the engine cleanliness and to be compliant with the limits set by the automobile industry. It should be noted that these good results in engine cleanliness are obtained with different contents of oil of group V according to the invention.