Use of esters in a lubricant composition for improving cleanliness of an engine

Abstract

The present application relates to the use, in a lubricant composition comprising at least one base oil, of 2 to 12% by weight, relative to the weight of said lubricant composition, of an ester that has a viscosity at 100° C. of between 200 and 1000 cSt, for the purpose of improving the cleanliness of an engine.

Claims

1. A method for improving the cleanliness of a marine engine comprising lubricating the engine with a lubricant composition comprising at least one base oil and 2 to 12 wt % (by weight of the lubricant composition) of an ester having a viscosity at 100° C. between 250 and 1000 cSt, wherein the ester is not a glycerol ester, and wherein the ester is obtained by reacting an alcohol and an acid that comprises from 4 to 36 carbon atoms.

2. The method according to claim 1, wherein the viscosity of the ester at 100° C. is between 250 and 900 cSt.

3. The method according to claim 1, wherein the ester is included in a proportion of 2 to 11 wt % by weight of the lubricant composition.

4. The method according to claim 1, wherein the ester is obtained by reacting an alcohol and an acid, and wherein the alcohol forming the ester is a monoalcohol.

5. The method according to claim 1, wherein the ester is obtained by reacting an alcohol and an acid, and wherein the acid forming the ester is selected from the group consisting of acid anhydrides and fatty acids.

6. The method according to claim 4, wherein the acid is selected from the group consisting of acid anhydrides and fatty acids.

7. The method according to claim 5, wherein the carbon chain of the acid anhydrides or fatty acids is functionalized by one or more groups selected from the group consisting of carboxylic acids, amides, ureas, urethanes, amines, polyisobutadienes, and alcohols.

8. The method according to claim 6, wherein the carbon chain of the acid anhydrides or fatty acids is functionalized by one or more groups selected from the group consisting of carboxylic acids, amides, ureas, urethanes, amines, polyisobutadienes, and alcohols.

9. The method according to claim 1, wherein the engine is a 2-stroke marine engine.

10. The method according to claim 1, wherein the ester is obtained by reacting an alcohol and an acid, and wherein the alcohol forming the ester is a polyalcohol.

Description

(1) The temperature resistance of the compositions was thus evaluated by means of the ECBT test. A detailed description of this test can be found in the publication “Research and Development of Marine Lubricants in ELF ANTAR France—The relevance of laboratory tests in simulating field performance”, by Jean-Philippe ROMAN, MARINE PROPULSION CONFERENCE 2000—AMSTERDAM—29-30 Mar. 2000.

(2) The results are shown in table 4 below.

(3) The results show that the compositions according to the invention have good temperature resistance, and are thus able to improve engine cleanliness.

(4) TABLE-US-00005 TABLE 4 COMPOSITIONS CI1 CI2 CI3 CI4 CI5 CI6 Score at 73.6 92.3 88.5 62.9 63.9 45.7 280° C. Critical 289° C. 289° C. 295° C. 285° C. 283° C. 282° C. temperature measured at score of 50 COMPOSITIONS CC1 CC2 CC3 CC4 CC5 CC6 Score at 32.2 40.1 34.1 28.8 12.2 47 280° C. Critical 277° C. 278° C. 277° C. 276° C. 274° C. 279° C. temperature measured at score of 50

(5) When determining the score at 280° C., if the surface is free of coating, the score is 100. In other words, the lower the score, the more coating there is on the surface.

(6) The critical temperature corresponds to the temperature at which the surface has a coating with a score of 50.

(7) These results show that esters having a viscosity according to the invention allow advantageously for improvements in engine cleanliness compared to lubricant compositions lacking such esters and compared to lubricant compositions comprising esters having different viscosities. In fact, the coating score is closer to 100 with the esters according to the invention. Additionally, the critical temperature is considerably greater for the esters according to the invention.

(8) These results also show the influence of the quantity of ester used.