US2304242A

US2304242A - Diesel fuel

Info

Publication number: US2304242A
Application number: US263407A
Authority: US
Inventors: Gould H Cloud
Original assignee: Standard Oil Development Co
Current assignee: Standard Oil Development Co
Priority date: 1939-03-22
Filing date: 1939-03-22
Publication date: 1942-12-08
Anticipated expiration: 1959-12-08

Description

Patented Dec. 8, 1942 DIESEL FUEL Gould 11. Cloud, Elizabeth, N. J.,assigno1 to Standard 011 Development Company, a corporation of Delaware No Drawing. Application March 22, 1939, Serial No. 253,407

6 Claims.

This invention relates to a stabilization of compression-ignition engine fuels and is concerned particularly with improved fuel compositions adapted for high speed engines of the Diesel type by addition compounds which enhance ignition qualities of the fuel.

In most instances, addition compounds which have been recommended foraccelerating ignition of hydrocarbon oils in Diesel engines .have characten'stically contained oxygen, nitrogen, and

sulfur, in highly unstable groupings. While it is true that many of these proposed compounds are very efiective in shortening thedelay period between injection and spontaneous ignition of the fuel, particularly when the fuel isfreshly made up, a reduction in their eifectiveness tends to occur during storage owing to their inherent instability. Not only do these unstable compounds tend to deteriorate, but on deteriorating they tend to induce oxidation of hydrocarbons in the fuel which results in gum formation and further, they tend to develop corrosive decomposition products in storage and in operation of the engines.

The objectof this invention is to provide an improved Diesel fuel composition with a novel stabilizing agent, which, added to the fuel by itself or in combination with unstable types of ignition promoters, has a definite and substantial beneficial influence on the ignition quality of the fuel.

Compounds suitable for use as stabilizing promoters according to: the present invention are certain organic nitrogen compounds characterized'by having adequate solubility in hydrocarbon oil and chemical properties which adapt them for inhibiting oxidation and corrosion. Compounds responding to these requirements were I found to be notably hydrazines, certain hydrazine derivatives, and certainrelated'nitrogen bases. These compounds behave exceptionally well in enhancing the qualities of Diesel fuel oils, since, in general, the presence of an amino or an imino group in a compound has appeared to counteract ignition-promoting action generally, for example, aromatic amines, e. g aniline, and their usual derivatives, including azo and hydrazo compounds, have been determined to be detrimental to the ignition qualities of a fuel.

Hydrazines which are used in the-practice of this invention belong .to a well known class of unsymmetrical compounds identified by the presence of nitrogen in the groupings NH-NH2,/

-hhNH; and NH-NH--. Members of this class of compounds found to be preferably useful are dimethyl hydrazine, phenyl hydrazine, diphenyl hydrazine, and methyl. phenyl hydrazinein each'instance, the methyl and phenyl groups being replaceable by higher homologous hydrocarbon radicals. Similarly suitably hydrazine rderivatives and related nitrogen bases are quin- 'alyl hydrazine, acetyl phenyl hydrazine, 3-amino phthal hydrazine, carbazole, 5-amino uracil, and

tribenzyl amine.

The manner of employing the compounds which possess desirable properties for promoting qualities and stability in Diesel fuels and of testing their eflicacy in these respects is illustrated in the following description. A number of samples were prepared by dis solving from less than 1% to about 3% by vol--. gl5 ume of the compound to be tested in a portion of a 40 cetane number gas oil, and each sample was tested in a high speed Diesel engine according to the method disclosed in the S. A. E. Journal of June, 1936, page 225. Each sample was rated on its cetane number by comparison with blends consisting of cetane and alpha meth-. yl naphthalene. Since the ignition lag of a blend consisting of normal cetane and alpha-methyl naphthalene is shortened very nearly in propor- 25. tion to the increase in percentage of cetane by volume, the ignition quality of a fuel can be evaluated in terms of the cetane content of such I a blend giving comparable performance in the test engine. i

Even though a number of aliphatic amines,

aromatic amines, and their derivatives consistently showed an adverse eifect on the cetane number of the fuel samples, the dialkyl, diaryl, and alkyl-aryl hydra/zines and hydrazine derivatives, particularly those enumerated, made a substantial improvementin ,the cetane number of thefuel. The compounds selected as preferable are those which increase the cetane number of a fuel on the order of 2 or more points when incorporated in concentrations of less than about 1% by volume of the fuel. Further tests on fuel samples blended with mixed ignition promoters show that by-usingthe compounds capable of promoting and stabilizing ignition qualities of the fuel together with addition compounds having higher potency for accelerating ignition but lacking stability, the ignition qualities of the blended fuel is increased at least in proportion to the 50. effect of each promoter. Considerable importance is attached to this fact, because ignition I promoters are clostly in comparison to the value of hydrocarbon fuels, making lthighly desirable to eliminate any detrimental influence of promoters without impairing their ignition accelerating action.

To prepare the Diesel fueLcompositions which can be stored for long periods without detriment to the ignition qualities, also with reduced acid and sludge formation, the ignition promoting- 2 stabilizing compound need be used only in less than about 1%, whether used alone or together with .5% to about 5% of addition compounds such as aromatic peroxides, aliphatic nitrates, aliphatic nitrites, aliphatic polysulfides, and the like. About .2% to 1% of the stabilizing promoter is generally adequate, but with more readily oxidizable fuels or more unstable addition compounds as much as 3% may be used.

Every hydrocarbonv oil suitable as a fuel for Diesel engines may be improved in the described manner. Ordinarily, the hydrocarbon fuel to be used may be said to have a boiling range above that of gasoline, and, more particularly, the boiling range and viscosity of hydrocarbons present in a gas oil which boils from 400 F. to 700 F.

Under some circumstances, a more narrowly cut fraction such as one distilling from about 400 F.

' or 450 F. to 800 F. may be used. Considerable for enhancing various other qualities without detracting substantially from the ignition qualities of the fuel may be admixed, such as oiliness agents, dyes, pour point depressants, and viscosity modifiers.

Practical advantages obtained in using'the stabillsing promoters are:

1. Economy in the use of more potent ignition promoters which are subject to degradation when used without a stabilizing agent:-

2. Protection of storage tanks and engine parts from corrosive decomposition products of the more potent ignition promotersr 3. Stabilization of the fuel against the aeve tpment of insoluble gums and resins which tend to clog fuel lines and atomizers; and r 4. Elimination of substances having harmful and annoying physiological effects from exhaust gases.

The above description and examples are to be taken as illustrative only and not as limiting the scope of the invention. Any modification or variation therefrom which conforms to the spirit of the invention is intended to be included within the scope of the claims. I

I claim:

1. A compression-ignition engine fuel comprising a hydrocarbon oil boiling from 400 F, to 700 F. and as an ignition improver and stabilizing agent a minor amount of anessentially hydrocarbon unsymmetrically substituted hydrazine com pound selected from the group consisting of dialkyl hydrazines, phenyl hydrazine,' diaryl hydrazines, alkylaryl hydrazines, quinalyl hydrazine, acetyl phenyl hydrazine, 3-amino phthal hydrazine 2. A fuel composition described in claim 1 having admixed therewith a minor amount-of an ignition accelerating agent selected from the class consisting of aliphatic" nitrates, aliphatic nitrites, aromatic peroxides, and aliphatic polysulfldes.

3. A compression-ignition engine fuel comprising a hydrocarbon Diesel fuel oil and as an igni- .tion improver and stabilizing agent a minor amount of an unsymmetrical hydrazine containing a hydrocarbon substituent radical.

4. A compression-ignition engine fuel comprisin a hydrocarbon Diesel fuel oil and .2.% to 1% of phenylhydrazine.

5. A compression-ignition engine fuel compris- 8' a hydrocarbon Diesel fuel oil and 2% to'1.% of methyl phenyl hydrazine.

6. A compression-ignition engine fuel comprising a hydrocarbonDiesel fuel oil and .2% to 1% of an unsymmetrical essentially hydrocarbon diaryl hydrazine.

\ GOULD H. CLOUD.