US2672450A - Composition for removing adherent deposits from internal-combustion engines - Google Patents

Description

Patented Mar. 16, 1954 COMPOSITION FOR DEPOSITS FROM I ENGINES REMOVING ADHERENT NTERNAL-COMBUSTION Howard W. Pearsall, Highland Park, Mich., as-

signor to General Motors Corporation, Detroit, Mich, a corporation of Delaware No Drawing. Application June 28, 1950, Serial No. 170,948

Claims.

This invention relates to the removal of deposits of carbon and other substances, and particularly to improvements in compositions of matter for loosening these deposits and to a process for eifecting the removal thereof.

The principal object of the invention is to provide a liquid mixture which may be employed to effectively loosen the carbon and other adherent deposits from the surfaces of metal parts, such as combustion chambers, pistons, cylinder heads and valves, of an internal combustion engine. A. further object of the invention is to provide such a composition which is inexpensive, efficient and has no detrimental effects upon the metal parts or crankcase lubricant with which it comes into contact.

It is well-known that solid deposits, consisting principally of carbon and other products of the.

combustion of the fuel mixtur and lubricating oil, adhere to the piston heads and other interior parts of internal combustion engines to the detriment of efiicient engine operation. These deposits usually decrease the life of the exhaust valves, lower the efiiciency of heat transfer to the cooling jacket, reduce the capacity of the engine to take in a full charge of air and fuel, and, in the case of Otto cycle engines, increase the tendency of the fuel to detonate or knock. It follows, therefore, that a means of easy and efiective removal of such deposits is of great value, particularly if such means can be employed without disassembling the engine as is customarily required. Moreover, it appears likely that if engine manufacturers could be assured that an easy method of removing combustion chamber deposits were available to the public, they would feel free to build engines having higher compression ratios and therefore of higher efii ciency, with consequent great benefit to engine users in the future.

In general, this invention materially facilitates deposit removal by providing liquid mixtures comprised of mono-alkyl ethers of glycols, especially the mono-alkyl ethers of ethylene glycol and diethylen glycol; lower-alkyl substituted benzenes; and an alkyl ester of a fatty acid. The lower-alkyl substituted benzenes which I found to be of particular value were toluene and homologues thereof having a total of 7 to 10 carbon atoms, xylene and aromatic high-flash solvent naphthas being examples of these homologues which proved highly satisfactory. All-of the aforementioned materials, when first combined, readily form a homogeneous mixture which is ready for immediate use.

Among the esters which I have found to be of particular value are the 1-to-6 carbon alkyl esters of a fatty acid having 14 to 18 carbon atoms. Examples of the latter are methyl ricinoleate and ethyl ricinoleate, the addition of only a relatively small amount of these esters greatly enhancing the deposit-loosening qualities of the mixture, apparently because of a wetting or penetratingproperty possessed by such esters.

In accordance with the invention, I have found that a mixture of ethylene glycol monomethyl ether, xylene, and methyl or ethyl ricinoleate is effective in the removal of carbon and other adherent deposits from the interior of internal combustion engines. I have also found that the utility of this mixture as a carbon remover is further increased by the addition of substantial amounts of diethylen glycol monomethyl ether and of an aromatic high-flash solvent naphtha, these substances being less volatile than xylene and ethylene glycol monomethyl ether. The high-ilash solvent naphtha employed is a coal tar distillate boiling between 250 F. and 490 F.

The application of highly volatile solvents to hot surfaces tends to vaporize and disperse them before they can exert much solvent effect. Less volatile solvents, on the other hand, although having less tendency to immediately vaporize, normally do not have as great a solvent power as do the more volatile compounds. As stated above, however, I have provided a unique and efiicient mixture of high-boiling and low-boiling solvents Which is particularly suited for the removal of the objectionable carbon deposits. In this mixture, the advantages of high solvent power possessed by the lower-boiling, low molecular weight solvents are almost entirely retained, and at the same time the tendency of these to be lost through quick vaporization is materially decreased by the presence of the higher-boiling solvents.

As hereinbefore explained, the addition of particular lower-alkyl esters of long-chain fatty acids, such as methyl ricinoleate and ethyl ricinoleate, greatly increases the eiiectiveness of the mixture because of the wetting action thereby provided. I have found these surface active agents to be effective within the practical addition limits of 0.1% to 10% by volume of the aforementioned mixture, approximately 2% by volume being the optimum amount to be added. Additions of this agent to the above mixture in a quantity beyond 10% by volume appears to create no additional beneficial results.

In accordance with these findings, I hav obtained commercially practical resultswith a mix ture comprising approximately 25% to by volume of lower-alkyl substituted benzenes, to 75% by volume of mono-alkyl ethers of glycols, and 0.1% to 10% by volume of a loweralkyl ester of ricinoleic acid. Thus a mixtur of 49% of ethylene. glycol. monomethyl. ether, 49% of xylol, and. 2% of the ricinoleate proved satisfactory and had good deposit-loosening properties. As hereinbefore explained, moreover, I have found that the addition of an aromatic high-flash solvent naphtha boiling between 250 F. and 400 F. and diethylene glycol monomethyl ether further increases the solvent action of the mixture. Outstanding results, for example, are achieved with a mixtur having approximately equal proportions of the four major constituents, or one in which the proportions of these constituents are varied within only relatively restricted limits, such as one comprising 12% to 38% by volume of Xylene, 12% to 38% by volume of. ethylene glycol monomethyl ether, 12% to 38% by volume of the aromatic high-flash solvent naphtha, and 2% to 38% by volume of diethylene glycol monomethyl. ether, to which. mixture is added, 01% to 10% by volume of methyl or ethyl ricinoleate.

Ordinarily, the best method of using the aforementioned d'eposit-removing solution is to apply it to the coated parts. without disassembling the engine, after these parts have become heated by actual operation of the engine. Thus, in watercooled engines, the coolant in the cooling jacket should be above 150F.

By way of example, we. may form a mixture of 24.5% by volume of ethylene glycol monomethyl ether, 24.5% by volume ofv diethylene glycol monomethyl ether, 24.5% by volume of xylene, 24.5% by volume of the aromatic high-flash solvent naphtha, and. 2% by volume of methyl ricinoleate, which compounds are mutually soluble, and then inject to 90 milliliters of this composition into the combustion chamber of each cylinder. This is preferably done after the engine has been operated for a period of time so that the coated metal parts become heated. Specifically, one of the best methods for applying the mixture to the engine is to slowly introduce asuitable quantity of it into the carburetor air intake while the engine is idling, the last onefourth to one-sixth of the liquid being added at such an increased rat as to stall the engine.

The mixture is permitted to act on the deposits for a suitable period of time, depending upon the nature of the coating to be removed. In most cases, I have found that from about one to six hours'is a sufiicient length of time to obtain exoellentresults. The engine is then started and the loosened carbon and other deposited particles are blown out through the exhaust.

As an alternative, the coated parts may be removed from the engine and heated over a flame or otherwise, the carbon-removing composition applied by immersion, spraying, painting, or other suitable means, and the loosened deposit wiped, brushed or blown from the metal surfaces. Although heating accelerates the solvent action and thereby reduces the necessary period of solvent activity, the mixture may be applied to the coated parts at ordinary temperatures.

It is to be understood that while the invention has been described in conjunction with certain specific examples, the scope of the invention is not to be limited thereby except as defined in the appendedclaim's.

I claim:

1. A composition for removing adherent deposits from surfaces of internal combustion engines comprising, by volume, 25% to 75% of lower-alkyl substituted benzenes having a total of 7 to 10 carbon atoms, 25% to 75% of at least one glycol monomethyl ether and. 0.1% to 10% of a. lower-alltyl ester of ricinoleic acid.

2. A composition for removing adherent deposits from metal surfaces comprising, by volume, 25% to 75% of at least one glycol monomethyl ether, 25% tov 75% of at least one lower-alkyl substituted benzene selected from the class consisting of xylene and an aromatic high-flash solventnaphtha boiling between 250 F. and 400 F., and 0.1% to 10%-of a lower-alkyl ester of ricinoleic acid.

3. A composition for removing carbon and like deposits from metallic surfaces comprising, by volume, 25% to 75% of ethylene glycol monomethyl. ether, 25% to 75% of xylol, and 0.1% to 10% of an ester of the class consisting of methyl rieinoleate and ethyl ricinoleate.

4. A composition for removing carbonaceous deposits from metallic. surface comprising, by volume, approximately 49% of ethylene. glycol monomethyl. ether, 49%. of xylol and 2% of. an ester of. the class consisting of methyl ricinoleate and ethyl ricinoleate.

5. A. composition for removing carbonaceous deposits from surfaces of internal combustion engines comprising, by volume, 25% to 75% of a lower-alkyl substituted benzene having a totalof 7 to 10 carbon atoms, 25% tov 75% of an ether of the class consisting of ethylene glycol monomethyl ether and diethylene glycol monomethyl ether, and 0.1% to 10% of a. lower-alkylester of ricinoleic acid.

6. A composition for removing organic deposits from the walls of engine combustion chambers comprising, by VOlllIIlG, 25% to 75% of a loweralkyl substituted benzene having a total of 7 to 10 carbon atoms, 25% to 75% of a mixture of ethylene glycol monomethyl ether and diethylene glycol monomethyl ether, and 0.1 to 10% of an ester of the class consisting of methyl ricinoleate and ethyl ricinoleate.

7. A composition for removing carbonaceous deposits from surfacesof internal combustion engines comprising, by volume, 25% to 75% of monomethyl ether of glycol, 25% to 75% of a mixture of xylol and an aromatic high-flash solvent naphtha boiling in the range between 250 F. and 400 F., and 0.1% to 10% of an ester of the class consisting of methyl ricinoleate and ethyl ricinoleate.

8. A composition for removing organic deposits from surfaces of internal combustion engines comprising, by volume, 12% to 38% of xylene, 12% to 30% of an aromatic high-flash solvent naphtha boiling in the range between 250 F. and 400 F., 12% to 38% of ethylene glycol monomethyl ether, 12% to 38% of diethylene glycol monomethyl ether, and 0.1% to 10 of methyl ricinoleate.

9. A liquid organic solvent. for removing adherent deposits from-internal combustion engines, comprising substantially equal proportions by volume of xylene, an aromatic high-flash solvent naphtha boiling between 250 F. and 400 F., ethylene glycol monomethyl ether and diethylene glycol monomethyl ether, and 0.1% to 10% by volume of methyl ricinoleate.

10. A composition for removing deposits from combustion chambers of internal combustion engines comprising, by volume, approximately 24.5% of ethylene glycol monomethyl ether,

24.5% or dlethylene glycol monomethyl ether, 24.5% of xylol, 24.5% of an aromatic high-flash solvent naphtha boiling between 250 F. and 400 F., and 2% of methyl ricinoleate.

11. A method of removing deposits from surfaces of internal combustion engines which comprises applying to the deposit a mixture comprising approximately 25% to 75% by volume of lower-alkyl substituted benzene having a total of 7 to 10 carbon atoms, 25% to 75% by volume of at least one glycol monomethyl ether and 0.1% to 10% by volume of a lower-alkyl ester of ricinoleic acid, and removing the loosened deposits.

12. The process of removing organic deposits from the combustion chamber of an internal combustion engine which comprises applying to the deposit a mixture consisting essentially of 12% to 38% by volume of xylene, 12% to 38%. by volume of an aromatic high-flash solvent naphtha boiling between 250 38% by volume of ethylene glycol monomethyl ether, 12% to 38% by volume of diethylene glycol monomethyl ether, and 0.1% to 10% by volume of a lower-alkyl ester of ricinoleic acid, and removing the loosened deposit.

13. The process of removing organic deposits from the combustion chamber of an internal combustion engine which comprises heating the coated parts, applying to the deposit a mixture consisting essentially of 0.1% to 10% by volume of methyl riclnoleate and approximately equal proportions of xylene, an aromatic high-flash solvent naphtha boiling in the range between F. and 400 F., 12% to lit 250 F. and 400 F., ethylene glycol monomethyl ether, and diethylene glycol monomethyl ether. and removing the loosened deposit.

14. A composition for removing adherent deposits from metal surfaces comprising, by volume, 25% to 75% of a mixture of lower-alkyl substituted benzenes each having a total of 7 to 10 carbon atoms, 25% to 75% of a mixture of glycol monomethyl ethers, and 0.1% to 10% of at least one member selected from a class consisting of methyl ricinoleate and ethyl ricinoleate.

15. A composition for removing adherent deposits from metal surfaces comprising approximately 12% to 38% by volume of xylene, 12% to 38% by volume of an aromatic high-flash solvent naphtha boiling between 250 F. and 400 F., 12% to 38% by volume of ethylene glycol monomethyl ether, 12% to 38% by volume of diethylene glycol monomethyl ether and 0.1% to 10% by volume of a lower-alkyl ester of ricinoleic acid.

HOWARD W. PEARSALL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,820,395 Lovell et a1. Aug. 25, 1931 2,168,024 Ensminger Aug. 1, 1932 2,236,590 Backofl et a1. Apr. 1, 1941 2,251,988 "Curran Aug. 12, 1941 2,474,437 Potter et a1. June 28, 1949

Claims (1)

1. A COMPOSITION FOR REMOVING ADHERENT DEPOSITS FROM SURFACES OF INTERNAL COMBUSTION ENGINES COMPRISING, BY VOLUME, 25% TO 75% OF LOWER-ALKYL SUBSTITUTED BENZENES HAVING A TOTAL OF 7 TO 10 CARBON ATOMS, 25% TO 75% OF AT LEAST ONE GLYCOL MONOMETHYL ETHER AND 0.1% TO 10% OF A LOWER-ALKYL ESTER OF RICINOLEIC ACID.