USE OF LUBRICATING COMPOSITIONS TO IMPROVE THE CLEANLINESS OF A 4-STROKE VEHICLE ENGINE

Abstract

The invention relates to the use of an alcohol of formula ROH (I), in which R is a linear or branched saturated alkyl group with 10 to 36 carbon atoms, in a lubricant composition to improve the cleanliness of a 4-stroke vehicle engine.

Claims

1. A method for improving the cleanliness of a 4-stroke vehicle engine comprising the lubrication of the engine with a lubricant composition comprising an alcohol of formula (I)
ROH (I) where R is a saturated, linear or branched alkyl group having 10 to 36 carbon atoms, in a lubricant composition to improve the cleanliness of a 4-stroke vehicle engine.

2. The use according to claim 1, wherein the alcohol is selected from among the compounds of formula (I) where R is a saturated, linear or branched alkyl group having 12 to 36 carbon atoms.

3. The method according to claim 1, wherein the alcohol is selected from among the compounds of formula (Ia)
R.sup.1C(R.sup.2)(H)CH.sub.2OH (Ia) where R.sup.1 and R.sup.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.

4. The method according to claim 1, wherein the lubricant composition comprises at least one base oil.

5. The method according to claim 1, wherein 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.

6. (canceled)

Description

[0088] FIG. 1: Photo of piston underside after engine testing with a comparative composition (CC1).

[0089] FIG. 2: Photo of piston underside after engine testing with a composition of the invention (CI8).

[0090] The different aspects of the invention can be illustrated by the following nonlimiting examples:

EXAMPLE 1

Lubricant Compositions of the Invention

[0091] The different components of the reference lubricant composition Cref1 were mixed according to the type and amounts given in Table 1.

TABLE-US-00002 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.sup.2/s) Gr III base oil (kinematic viscosity at 100 C. measured 20.6 as per standard ASTM D-556 = 7 mm.sup.2/s) PAO-type base oil (kinematic viscosity at 100 C. 30.0 measured as per standard ASTM D-556 = 4 mm.sup.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)

[0092] 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-US-00003 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.sup.1 Myristyl 2 4 alcohol.sup.2 Cetyl 2 alcohol.sup.3 .sup.1Ecorol 12/98 marketed by Ecogreen Oleochemicals .sup.2Ecorol 14/98 marketed by Ecogreen Oleochemicals .sup.3Ecorol 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

[0093] 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.

[0094] 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-US-00004 TABLE 3 Cref CI1 CI2 CI3 CI4 CI5 CI6 Score 7.4 8 7.9 7.9 7.9 7.8 7.7

[0095] 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

[0096] 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-US-00005 TABLE 4 CI8 CC1 Gr III base oil (kinematic viscosity at 62 64 100 C. measured as per standard ASTM D-556 = 4 mm.sup.2/s) Gr III base oil (kinematic viscosity at 15 15 100 C. measured as per standard ASTM D-556 = 6 mm.sup.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 .sup.4 2 .sup.4 Ecorol12/98 marketed by Ecogreen Oleochemicals

[0097] The engine cleanliness performance of the lubricant compositions CI8 and CC1 was evaluated with the following method.

[0098] 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).

[0099] 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.

[0100] The results obtained are grouped together in Table 5.

[0101] The regular passing of a reference oil showed that a difference of 4 points between two candidates is significant.

[0102] 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-US-00006 TABLE 5 Evaluated composition Mean piston score after testing CI8 68.5 CC1 61.6

[0103] 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).

[0104] 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

[0105] 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-US-00007 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.sup.2/s) Gr III base oil (kinematic viscosity at 10.8 10.8 100 C. measured as per standard ASTM D-556 = 8 mm.sup.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.sup.5 1 .sup.51-dodecanol marketed by Sigma Aldrich

[0106] 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:

TABLE-US-00008 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.

[0107] After this test, the engine parts were analysed and rated in the manner described in the procedure published in ASTM D7320.

[0108] 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-US-00009 TABLE 7 CC2 CI9 Mean of total score 4.28 4.76 Final result

[0109] 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

[0110] The compositions in Table 8 were tested for their cold start properties:

TABLE-US-00010 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.sup.6 0 0.5 1 2 .sup.6ISOFOL C12 alcohol of formula (Ia) in C12.

[0111] The results obtained are given in Table 9.

TABLE-US-00011 TABLE 9 Standards CC3 CI10 CI11 CI12 KV40 ISO 3104 93.67 90.92 88.91 85.04 (mm.sup.2 .Math. s.sup.1) KV100 ISO3104 14.18 13.94 13.7 13.26 (mm.sup.2 .Math. s.sup.1) VI ISO2909 156 157 157 157 CCS at ASTM 5390 5280 5150 4930 35 C. D5293 (mPa .Math. s) MRV (cP) ASTM 24060 22630 21580 20460 D4684

[0112] 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.

[0113] 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.

[0114] These results show that the branched alcohols of the invention afford improved cold start properties of the lubricant.