GASOLINE-BENZENE FUEL FOR AUTOMOBILE ENGINES IN THE USSR

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP80-00809A000700030681-1
• Release Decision: RIPPUB
• Original Classification: R
• Document Page Count: 5
• Document Creation Date: December 22, 2016
• Document Release Date: October 14, 2011
• Sequence Number: 681
• Publication Date: January 16, 1952
• Content Type: REPORT

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CLASSIFICATION RESTRICTED
SECURITY INFORMATION R
REST
CENTRAL INTELLIGENCE AGENCY ORT
INFORMATION FROM
COUNTRY
SUBJECT
HOW
USSR DATE OF
INFORMATION
Economic - Liquid fuel
DATE DIST. (h
1951
Jan
1952
PUBLISHED
WHERE
PUBLISHED
DATE
PUBLISHED
Monthly periodical
Moscow
Mar 1951
LANGUAGE
SUPPLEMENT TO
REPORT NO.
TOU OOOSSUIT OOULIUI IIFOSSAnoa NnCTINI Ta ueoan manor
or Taa Illna STAns WIl ll^ Taa I.M. SOr 'am.... I AR SS
I. a. c., SI ASS IS IS 010011. In TIAOOUIWYI OA n5 OIIRRIia
0r Ill LOaTII71 la A1/ aAaaaa ID A. IIIAInouna raOOa la rao?
Nl1Raa 01 YS. UIRCIICTSS Or Tlla FOSS II P0Oalalna.
Table and figures are appended; all degrees arc centigrade,
Autombile transport in the USSR is receiving not only gasoline but also
benzene as fuel for carburetor engines. The benzene is used in mixtures with
gasoline, and the quality of the mixture is determined by the amount of each
entering into its composition. In the T5NIIAT (Central Scientific Research
Institute of Automobile Transport) tests were made of different gasoline-ben-
zene mixtures to check the suitability of their properties under operating con-
ditions.
To obtain the experimental mixtures, a nonethyl gasoline was selected which
had separated out when the temperature at the end of the distillation was 205
degrees. A bituminous coal benzene at present being supplied to automobile
transport was used to combine with this gasoline. They characteristics of these
fuels are in the appended table. Distillation curves of the two fuels and
various mixtures of them are shown in the graph in Figure 1.
This graph gives distillation curves for straight gasoline, straight ben-
zene, and for the following mixtures: 85 percent gasoline and 15 percent ben-
zene; ?5 percent gasoline and 25 percent benzene; 65 percent gasoline and 35
percent benzene; 50 percent gasoline and 50 percent benzene.
The distiliation curves indicate that the addition of benzene to gasoline
in no way increases the temperature at the beginning of the distillation but
considerably improves the course of all the remaining parts of the curves.
Even the 10 percent point for mixtures containing 50 percent benzene and less
is completely satisfactory. Points further on-are more favorable for gasoline-
benzene mixtures than for straight gasoline. This gives evidence of the increase
in vapor pressure of saturated vapors of all fractions of gasoline-benzene
mixtures eiccept for the lightest top fractions.
} sTR~OTE
STATE NAY I NSRs _RT ARMY )' AIR FBI
DISTRIBUTION
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However, it must be remembered that the vaporizability of fuels in car-
buretor engines depends not only on the fractional composition and vapor pres-
sure but also on the heat of vaporization and the amount of air in the working
mixture.
The heat of vaporization of benzene is higher than that of gasoline (more
than 40 percent higher at 20 degrees). This creates difficulties in the vapori-
zation of benzene. If used in its pure form, a more thoroughgoing preheating
of the intake manifold is required and starting the engine is difficult. Because
of the high heat of vaporization of benzene, the temperature in the intake mani-
fold is greatly lowered. In starting the engine when the temperature of the
outside air is even 10 degrees, it is observed that the benzene congeals in
the fuel atomization system, with the precipitation of crystals particularly in
the diffuser of the carburetor, in the baffle plate, etc. However, for a mix-
ture containing 30 percent benzene, the beat of vaporization is only 10-12 per-
cent higher than for gasoline (under the same conditions). With a further
decrease in the benzene content of the mixture, the heat of vaporization is also
decreased.
For the complete combustion of one kilogram of benzene 13.2 kilograms of
air are required, as against 15 kilograms for gasoline, that is, 12 percent less
(by weight) than for gasoline. This impairs the vaporizability of benzene in
carburetor engines. However, gasoline-benzene mixtures require more air for
combustion than benzene does. Thus, for the combustion of a mixture containing
35 percent benzene, 14.4 kilograms of air are needed, or 4 percent less than
for the combustion of gasoline, and for the combustion of a mixture containing
25 percent benzene, 14.55 kilograms of air are required, or 3 percent less than
for straight gasoline.
The negative qualities of benzene (the increased heat of vaporization and
the somewhat smaller amount of air required for combustion) which impair its
vaporization in engines decrease when it is used in mixture with gasoline. At
the same time, the vapor pressure from benzene-gasoline mixtures is higher than
that of straight gasoline. This compensates for the negative qualities men-
tioned above from the standpoint of fine vaporization of the mixture in the
carburetor engine. Mixtures containing up to 25-30 percent benzene are satis-
factory for use in automobiles in summer in the central belt of the USSR.
To estimate the carburetion properties of gasoline-benzene mixtures the
density, viscosity, and surface tension of the mixtures must be considered since
the flow of fuel from the jet tube and the atomization of fuel in the carburetor
system of the engine depend on these. The density of benzene as shown in the
table of characteristics is almost 20 percent higher than that of gasoline (at
20 degrees).
The viscosity of benzene as given in the table differs very slightly from
that of gasoline. The difference in the visconit' of gasoline and gasoline-ben-
zene mixtures is even less, and from the viewpoint of its influence on the flow
of fuel from the jet tube it can be disregarded.
The surface tension of benzene at 20 degrees is 27 percent hider than
that cf gasoline (see table) but, as regards the absolute amount, it still is
not high (t,ro fifths of the surface tension of water). The surface tension
of gasoline-benzene mixtures is less than that of straight benzene. Conse-
quently,at:,_:.ation of mixtures containing up to 25-30 percent benzene is
,41,eetner satisfactory and is hardly at all inferior to the atomization of
automobile gasoline.
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An important factor in estimating the possibility of using gasoline-
benzene mixtures as fuel for automobile engines under USSR climatic condi-
tions is the temperature at which the precipitation of benzene crystals is
observed and the consequent interference with the operation of the engine.
To assure dependable use of automobiles, it is necessary to select mixtures
of such a nature that the temperature at which crystals are formed in them is
definitely lower than the temperature of the air during the coldest part of the
season in which the mixtures are to be used. At the same time, the length of
the season during which the mixtures could be used should be as long as possi-
ble since replacing mixtures of one type with these of anctLer necessitates a
readjustment of the carburetor and other devices.
Technical benzene, in its pure form, crystallizes (congeals) at a tempera-
ture ranging from 5-5.4 degrees depending on its cb-mical purity and, consequently,
use of it under USSR climatic conditions is excluded. However, the presence of
gasoline in a mixture with benzene improves this situation, and with the increase
of the gasoline nntent the temperature at which crystals are formed is lowered
considerably. (See curve tk in Figure 2.)
Gasoline-benzene mixtures containing up to 25-30 percent benzene and 70-75
percent gasoline are entirely satisfactory for their vaporizability and other
carburetion characteristics for use in automcbiles in summer in the central belt
of the USSR. They are also completely satisfactory from the viewpoint of the
low temperature at which crystals are formed (minus 30 degrees).
In considering the properties of gasoline-benzene mixtures, it is necessary
to take into account the toxicity of benzene. Because of this, in 1949,
provisional health regulations (No 114-242) approved by the Chief Health Inspec-
tor of the USSR established that the amount of benzene allowable for use in
automobile fuel should not exceed 25 percent (by volume). This excludes the
use of mixtures with a benzene content higher than 25 percent. Consequently,
a mixture consisting of 75 percent gasoline and 25 percent benzene (by volume)
should be recommended as fuel for summer automobile transport. At lower tem-
peratures during the coldest part of the day a mixture with a benzene content
of not more than 20 percent may be used. If the air temperature should drop
below minus 25 degrees, but not below minus 40 degrees, tie benzene content in
the mixture must be reduced to 10-15 percent. Such mixtures in their carburetion
characteristics and the temperature at which crystals are formed assure depend-
able operation of the automobile and reduce difficulties arising from the con-
gealing of the benzene itself.
The use of benzene results in a large amount of deposit, and in gasoline-
benzene mixtures the deposit, naturally, increases with the increase of the
amount of benzene in the mixture. For this reason, too, it is best to limit
the amount of benzene in the mixture to 25 percent.
The calorific value of benzene is lower than thn. of gasoline, being about
9,500 calories per kilogram. However, a gasoline-benzene mixture containing up
to 25 percent benzene has a calorific value of 10,250 calories and is only
slightly inferior in this respect to gasoline. Accordingly, the consumption
of such mixtures in operating automobile engines approximates very closely the
consumption of gasoline.
The antiknock stability of technical benzene is relatively high; its octane
number do:termined by the motor method is 98-100 or higher. The presence of ben-
zetx in gasoline-benzene mixtures increases their antiknock stability, as is
shown in Figure 3.
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At the same time, benzene burns more sluggishly in the engines (particularly
lov-compr:ssionandengines), and the temperature of the cylinders, the bottom of
pistons, the starting valves is increased. The gasoline-benzene mix-
theture has this property to a lesser degree than straight benzene. However, in
using it a greater spark advance is necessary than when operating on nonetbyl
gasolines. When there is an insufficient spark advance, there is a low burning
of the working fuel on the line of expansion, and because of this superheating
and a drop in the performance and efficiency of the engine. Thus, in converting
automobile engines from gasoline to a gasoline-benzene mixture, in addition to
regulating the fuel level in the float chamber and adjusting the carburetor to
take the working mixture, 'assuring a good pickup of the automobile an, efficiency
im operation, it is necessary to pay proper attention to the spark advance.
Lppended table and figures folloxs,.7
Characteristics of Benzene and Gasoline Used to obtain Mixtures
Physicochemical
Properties
Density at 20 degrees (g/cu m)
Benzene
98-loo
0.879
0.734
GOST 3900-47
Kinematic viscosity at
20 degrees (centistokes)
Surface tension at 20 degrees
0.766
29.0
0.738
22
8
GOST 33-46
A
P
'
(dynes/cm)
.
.
. Reb.nder
s
method
Fractional composition:
BT ginning )
Beginning of distillation 75
42
GOST 2177-48
10% distillation at (degrees) 79
50% distillation at (degrees) 80
90% distillation at (degrees) 8o
74
132
187
End of distillation at (degrees) 94
Residue (percent) 1.6
Losses in distillation (percent) 0.4
205
1.5
0.9
Congelation point, Between
(degrees) 5 and 5.4
Test on copper plate Passed
Passed
Groz1II method
Acidity (mg KOR/100 ml) 2.88
1.91
COST 1784-47
Water soluble acids and Absent
alkalies
Mechanical admixtures Absent
and water
Absent
Absent
OST 7872 MI 25 ye-37
OST 7872
-39 MI-19v,
GOST 2706-44, and
GOST 2577-44
BEST31Cr )
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Distillation Temperature (degrees)
0.ec' ~ro v c b
.. O. u 9
Laic *00 :2 r
Content of Benzene in Gasoline-Benzene
Mixture, by Volume (%)
Figure 2. Density p 2o (at 20 (Iegrees), Tera eruture at Which Crystals
Are Formed tk, and the Amount of A!r L. (in kg) Required to
Burn One Kilogram of F':el for Gas,-line-Benzene Mixtures in
Different Combinations
Figure 3. Octane Numbers
of Gasoline-
Benzere Mixtures
in Different
Combination
0 ro 20 ,70 40 .CV
Content of Benzene in Gasoline-Benzene
Mixture, by Volume (y6) -
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