US2931775A - Internal combustion engine lubricant - Google Patents

Description

United States Patent I 2,931,775 INTERNAL COMBUSTION ENGINE LUBRICANT James L. Jezl, Swarthmore, Pa., assignor to Sun Oil Company, Philadelphia, Pa., a corporation of New Jersey No Drawing. Application December 16, 1954 a Serial No. 475,836 r 7 Claims. (Cl. 252-515 This invention relates to an improved lubricant for use in a spark ignition internal combustion engine.

During the course of normal operation, spark ignition internal combustion engines accumulate carbonaceous deposits in the combustion chambers thereof. Such deposits are deleterious in that they promote engine knocking and pro-ignition tendencies thereby causing higher octane fuel requirements. These deposits also increase engine wear and thus lessen the useful life of themgine. from decomposition of the lubricant and fuel, although inorganic materials derived from the decomposition of various organo-metallic fuel or lubricant additives such as tetraethyl lead, iron carbonyl, and the like may also be contained in the deposits. In view of the deleterious effects of combustion chamber deposit accumulation, it is important and desirable to provide means by which such deposit accumulation may be reduced.

The carbonaceous deposits are derived largely It has now been discovered that the accumulation of carbonaceous deposits in the combustion chamber of a spark ignition internal combustion engine can be lessened by incorporating in the lubricant used in said engine a minor amount of a material selected from the group consisting of polynitrate esters of polyhydric alcohols, mono-nitro mono-nitrate hydrocarbon derivatives, and dinitro alkanes.

The polynitrate esters of polyhydric alcohols used according to this invention are preferably dinitrate esters of dihydric alcohols having 3 or more carbon atoms per molecule. These preferred esters are sufliciently soluble in viscous mineral oil lubricants, and they have'sufiicient- 1y low volatility to be successfully used in reducing carbonaceous combustion chamber deposit accumulation according to the invention. The esters can contain substituent aliphatic or aromatic radicals. These radicals increase the solubility of the dinitrate esters in the lubricant; the radicals also decrease the ester volatility. It is also within the scope of the invention to incorporate trinitrate esters in the lubricant.

Examples of specific polynitrate esters which are useful as spark ignition engine lubricant additives according to this invention are: propylene glycol dinitrate, trimethylene glycol dinitrate, 1,3-butylene glycol dinitrate, 1,4- butylene glycol dinitrate, 2,3-butylene glycol dinitrate, 1,2-butylene glycol dinitrate, 1,5-amylene glycol dinitrate, 2,4-amylene glycol dinitrate, 1,2-amylene glycol dinitrate, 1,6-hexylene glycol dinitrate, 1,5-hexylene glycol dinitrate, 1,4-hexylene glycol dinitrate, 1,3-hexylene glycol dinitrate, 1,2-hexylene glycol dinitrate, 2,4-heptylene glycol dinitrate, 3-phenyl-1,2-proylene glycol dinitrate, 2,2-diethyl-l.3-propylene glycol dinitrate, 2-ethyl-1,3- hexylene glycol dinitrate, 2-ethyl-2-n-butyl-1,3-propylene glycol dinitrate, and the like.

The mono-nitro mono-nitrate hydrocarbon derivatives employed as lubricant additives according to this invention should have at least 3 carbon atoms per molecule in order that the additives be sufficiently soluble in viscous mineral oil lubricant. Straight 9; branched chain mononitro mono-nitrates having aliphatic or aromatic substituents can be used. Examples of specific mono-nitro mono-nitrates which are suitably used in accordance with this invention are: 2-nitro-propyl nitrate, 2-nitro-1 butyl nitrate, Z-nitro-l amyl nitrate, 2-nitro-1 hexyl nitrate, 2-nitro-1 heptyl nitrate, 2-methyl-2 nitro-1 butyl nitrate, 2-ethyl-2-nitro-1 bgtyl nitrate, 2-methyl-2 nitro-1 propyl nitrate, and the li e.

The dinitro alkane lubricant additives according to this invention can be either aliphatic or cyclic dinitro ,alkanes. It is preferred that these additives contain at least 3 carbon atoms so that they are suiiiciently soluble in viscous mineral oil lubricant. I Use of the higher dinitro alkanes, i.e. those having 6 or more carbon atoms is pre ferred since such compounds are less volatile than the lower dinitro alkanes. Straight or branched chain aliphatic dinitro alkanes can be used. It is preferred that Y the nitro group is attached to. the same carbon atom in both the aliphatic and cyclic dinitro additives of this invention since such additives are more readily prepared and are generally more eificacious in eifecting reduction of carbonaceous deposit accumulation according to this invention than are dinitro alkanes having the nitro groups attached to different carbon atoms. It is within the scope of the invention, however, to use the latter type dinitro alkanes-i.e. dinitro alkanes having the nitro groups attached to different carbon atoms, as viscous mineral oil lubricant additives.

Examples of specific dinitro alkanes which are suitable for use according to this invention are: 1,1-dinitro butane, 1,1-dinitro pentane, 1,1-dinitro hexane, 1,1-dinitro heptane, 1,1-dinitro octane, 1,1-dinitro nonane, 1,1-dinitro dccane, 1,1-dinitro undecane, 1,1-dinitro cycloheptane, 1,1-cyclohexane, 1,1-dinitro cyclopentane, 1,1-d-initro cyclooctane, 1,1-dinitro cyclononane, 1,1-dinitro cyclodecane, 1,1-dinitro-3-methyl cyclopentane, and the like.

In practicing this invention, the lubricant additive is added to the engine lubricant in minor amount suificient to substantially lessen the accumulation of carbonaceous deposits in the engine combustion chambers. Normally the addition of about 0.05% to 5% by weight and preferably about 0.1% to 2% of additive to the lubricant is sufiicient to effect substantial deposit accumulation decreases. On occasion, however, amounts of additive outside of the above cited ranges can advantageously be used.

The lubricant to which the polynitrate esters of polyhydric'alcohols, mono-nitro mono-nitrate hydrocarbon derivatives, or dinitro alkanes are added can be any of the known viscous mineral oil spark ignition engine lubricants. The lubricant may contain, in addition to the additives of this invention, any of various additives such as extreme pressure agents, detergent additives, and the like which are known in the art.

My invention is particularly useful when applied to spark ignition engines which operate on fuel containing an organo-metallic anti-knock agent such as tetraethyl lead or iron carbonyl or the like. Such organo-metallic additives decompose in the engine combustion chambers and the decomposition products become incorporated in carbonaceous deposits which are already on combustion chamber surfaces. These additive decomposition products promote pro-ignition and are otherwise deleterious when deposited in combustion chambers. Through practice of my invention, however, less of the additive decomposition products become incorporated in carbonaceous combustion chamber deposits due to the lessened accumulation of such carbonaceous deposits. Accordingly, pre-ignition and similar difficulties arising from the use of organo-metallic additives are reduced through practice of this invention.

It is theorized, however, that the additives increase the rate ot-combust ion-oflubricant'or lubricant residue in the engine combustion chambers thereby decreasing the accumulation of such residue. In any event, significant deposit accumulation decreases are obtained through practice of this invention. The beneficial results are evidenced,-' for example, by decreased octane fuel requirements to avoid I claim:

1. Spark ignition internal combustion engine lubricant consisting essentially of viscous mineral oil and a compound selected from the group consisting of dinitrate esters-of dihydric alcohols, mono-nitro mono-nitrate 'hydrocarbon derivatives, and dinitro alkanes, said compound having at least three carbon atoms per molecule, in minor amount sufiicient to substantially lessen the accumulation of carbonaceous deposits in the engine.

2. Spark ignition internal combustion engine lubricant consisting essentially of viscous mineral oil and a dinitrate ester of a dihydrio alcohol having at least three carbon atoms per molecule stantially lessen the posits in the engine. '3. Spark ignition accumulation of carbonaceous deinternal combustion engine lubriknock-ing in spark ignition engines.

in minor amount sutficient to sub- ,mono-nitro mono-nitrate hydrocarbon derivative having at least three carbon atoms per molecule in minor amount sufiicient to substantially lessen the accumulation of carbonaceous deposits in the engine.

4. Spark ignition internal combustion engine lubricant consisting essentially of viscous mineral oil and a dinitro alkane having at least three carbon atoms per molecule in minor amount sufiicient to substantially lessen the accumulation of carbonaceous deposits in the engine.

'5. Lubricant composition according to claim 4 wherein said dinitro alkane has both nitro groups attached to the same carbon atom. v

6. Lubricant composition according to claim 4 wherein said dinitro alkane is an aliphatic dinitro alkane.

7. Lubricant composition according to claim 4 wherein said dinitro alkane is a cyclic dinitro alkane.

References Cited in the file of this patent UNITED STATES PATENTS 1,800,997 Greenstreet Apr. 14, 1931 2,066,506 Woodbury Jan. 5, 193.7 2,378,466 Curme June 19, 1945 2,592,435 Lacomble Apr. :8, 1952 2,673,793 'Brodhacker 'Mar. 30, 1954 2,785,662 Boyce Mar. 19, 11957

Claims (1)

1. SPARK IGNITION INTERNAL COMBUSTION ENGINE LUBRICANT CONSISTING ESSENTIALLY OF VISCOUS MINERAL OIL AND A COMPOUND SELECTED FROM THE GROUP CONSISTING OF DINITRATE ESTERS OF DIHYDRIC ALCOHOLS, MONO-NITRO MONO-NITRATE HYDROCARBON DERIVATIVES, AND DINITRO ALKANES, SAID COMPOUND HAVING AT LEAST THREE CARBON ATOMS PER MOLECULE, IN MINOR AMOUNT SUFFICIENT TO SUBSTANTIALLY LESSEN THE ACCUMULATION OF CARBONACEOUS DEPOSITS IN THE ENGINE.