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Патент USA US2405560

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Patented Aug. 13, 1946
2,405,560
UNITED STATES PATENT‘ OFFICE
‘General Motors Corporation, Detroit, Mich, a
corporation .of Delaware
No Drawing. Application February 6, 1943,
Serial No. 475,003
1 Claim.
.
2.
--lv
This invention relates generally to fuels for
high-compression.
and
tion was an electric spark .at the spark plug or an
more particularly to fuels in which there is less
tendency to cause preignition when high com
pression internal combustion engines are oper
ated thereon than is the .case when present well
known fuels are used under» similar operating
incandescent particle of engine deposit at some
point in the combustion chamber.
The present invention has as its principal ob
vject the reduction or suppression of preignition
in spark ignition engines. In accordance with
conditions.
spark-ignition ‘ engines
regardless of whether the initial source of igni
'
theiinvention, this object is accomplished by the
'
:It has longbeen recognizedthatth'ere are two
distinguishable but related combustion-phenom
‘use .of fuels or gasolines containing addition
10 agents which affect the chemical composition and
ena that act as barriers to the utilization of
higher compression ratios in internal combustion
‘spark-ignition engines. By preventing the use
of higher compression ratios or higher pressures
attainedby other 'means, these two barriers pre
yent the attainment of fuel economy and em
oxidation characteristics andto some extent the
weight and other .mechanical characteristics of
I the combustion chamber deposits.
Acting upon the aforesaid conceptof the causes
namely, an uncontrolled ignition
1.5 .ofpreignition,
ahead of the spark ignition caused by incandes
ciency that would otherwise be possible.
These two barriers are: ?rst, knock and second,
‘preignition. Substantial progress has been made
in the control of» knock through the discovery of 20
the antiknock effect of lead alkylssuch as tetra
ethyl lead and through progress in the-manufac
ture of vhydrocarbon fuels having high antiknock
value.
ic'eiit particles of engine ‘deposits-an investiga
tionihas been made of theoxidation characteris
tics iofivarious combustionchamber deposits and
ofivario‘us mixtures of inorganic compounds with
carbon. Of particular signi?cance, _it has been
.foundthat certain compounds of leadcommonly
iound'in‘combustion chamber deposits have an
‘unusualand unexpected effect upon the igni
c
1 The present invention has as its principal ob 25 Jti'onand burning characteristics of carbon.
ject the control .of the second barrier, namely,
‘Gasolines used today in, automobile engines com
preignition in gasolinef-carbureted spark-ignition
.monlyncontaina small amount of ,lead alkyl an- , '
engines. In accordance with this invention, this
object is accomplished by the use of fuels con
I tiknock compound, tetraethyl lead being employed
often confused. Preignition, as the name implies,
is an ignition of the mixture in advance of the
the bromide and/or chloride compounds are used
as a fuel in internal combustion engines it is found
that the deposits on the walls "_of the combus
tion chamber contain carbon and various lead
commercially. Common automotive fuels may
taining addition agents which a?ectthe ignition 30 contain up to about 3 cc. of tetraethyl lead per
gallon of gasoline. Along with the tetraethyl
characteristics of the combustion chamber de
posits.
lead lvarious volatile alkyl halides are‘commonly
In order to make clear the object of this inven
employed, for exampe bromides and chlorides such
tion it'is necessary to distinguish between the
as ethylene dibromide andethylene dichloride.
phenomena of preignition and knock which are 35 Whe'n'a 'gasolinecontaining lead tetraethyl, and
regular, timed spark ignition. 'When preignition
- occurs in its _most objectionable form, the ob
server‘hears a loud “knock” similar to that which 40 compounds such as ‘lead bromide, basic lead bro
_mightrbe expected if the sparkhad been advanced
mide, lead chloride, basic lead-chiorideklead sul
far beyond itsnormal timing. During preigni
fateIand basic lead sulfate. Lead compounds such
tion the observer will goften ?nd that the electric
. spark ignition switch can be shut offend the_,.pre
as these and also engine deposits from leaded
gasolines exert a catalytic elfect and‘ not only
ignition'willcontinue unaffected. This is because,
45 lower the ignition temperature of carbon, but they
»preignition .is caused by incandescent particles
impart to the mixture an ability to continue to
burn after the primary source. of heat is removed
that isnot had by carbon alone.
vThe effect of several lead compounds on ig
nition temperature is given in Table I below in
of combustion'chamber deposit which are ‘under
going oxidation ,on the combustion chamber sur
face and causegignition; of, the fresh fuel mixture
, during compression and in advance of the electric
, spark at the'snarli plug-
which the ignition temperatures of I mixtures
'7
Knock is a phenomenon associatedwith the
' I containing 10 per cent of various substances and
scompressiomignition‘of an unburned mixture .of
.fuel . and .air ahead of .the . normal name front.
:7 .‘Ifh'e phenomena associated withknock canxoccurw55
/,90 per cent ‘of carbon, in the form of carbonv
black, were determined under'certain controlled
conditions:
.
u
,
_.
.
'
2,405,560
4.
Engine conditions maintained while using the
- TABLE I.
fuels:
I
Chemical for-
Material tested
I
mu 3
'
Speed __________ .._ 2000 R. P. M.
Spark advance____ 20°
ition tem- '
pgelrlatme' 0R
-
Air-fuel ratio_____ Ranged between 13 and 14 to 1
Pure carbon _______________________ ._
C ___________ __
Combustion chamber deposit from
Over 1200
‘
Compression ratio- 8.5 to 1
.
r
l
M. E. P _________ __ 90 lbs. per sq. in.
engine operated on gasoline con‘
taining Ethyl ?uid ______________________________ __
680-750
Individual lead compounds known
Table III given below shows data obtained
to exist in combustion chamber
10 from tests on late model test cars. During the
1 720 ~ I
?rst test, Car No. 1 was operated on ethyl gaso
1 727
line and Car No. 2 on ethyl gasoline containing
1 727
_
deposits:
'
Lead bromide _________________ _.
PbBI‘: _______ ._
Basic lead bromide.-.
PbO.PbB1,.__.
Lead chloride _______ _.
l; _______ _.
Basic lead chlor1de.Lead sulphate _______ __
PbO.PbCl,___
__
Basic lead sulphate ____________ __
>
.
1 939
Pb0.PbSO4___
1 950
the experimental conditions were, substantially
the same. In the second test, Car No. 2 ran on
15 ethyl gasoline containing 2 cc. per gallon of tri
‘ .butyl phosphite, while Car No. 1 was running on
1 Results obtained by averaging results-‘of fourseparate
determinations.
‘
;
~
1- cc. per gallon of tributyl phosphite; otherwise,
1727..
PbSO.;_ ___'..__ '
.
-
A
As indicated in this table, the halogen com
ethyl gasoline alone. At the end of each test
pounds _of lead are extremely active in promot
the engine deposits were removed, weighed and
ing the’ oxidation of carbon. Accordingly, the
analyzed. The results of the tests are tabulated
presence of these compounds in combustion 20 in Table III. These two tests demonstrate clear
chamber deposits will‘ tend to produce, preigni
ly the effect of the phosphorus additive on the
weights and chemical compositions of the engine
tion when other conditions are favorable..
I have found that the activating effect of lead
deposits, namely, a reduction in the lead, bro
on ignition of carbon can be inhibited and even mine, chlorine and sulphur in engine deposits
prevented altogether by-the presence of phos
from engines run on leaded-fuels.
phorus compounds. In accordance with. the
TABLE III
present invention,.there£or,.I propose a fuel for
EFFECT or TRIBUTYL Pnospnrrn 'ON ENGINE .Ds
internal combustion, spark-ignition engines con
> taining'a small peroentagegusually'less thanone
' per cent by volume, of a liquid phosphorus-con
POSITS or MULTICYLINDER» ENGINES WHEN IT IS
taining compound in addition to the other ingre
dients which have normally been used in leaded
End of ?rst 3,000~mile test \
Usnn IN THE FUEL TO INHIBIT PREIGmrroN
r aizgdlz
gasolines heretofore. vThe phosphorus-contain
Car No. 1 Y
ing compound should be soluble in the gasoline
‘and of sufficient volatility. asto vaporize with
the hydrocarbonv constituents of ‘the gasoline.
a5:
Properties of deposits’
>
phite
Heads
of a readily available liquid, organic, compound
of phosphorus of suitable-volatility andsolubil-v
Weight ________ __grams__
ity in gasoline which I have found. to be e?ective 40 Chemical analysis:
.
Brominauperpcentu
in concentrations less than one-tenth of vone per
Chlorine ____ __do___.
cent by volume. Tests indicate that the ignition
Sulphur _____ _.do.___
tively small amounts of tributyl .phosphiteare
increased substantially as compared with depos
its obtained from similar fuels containing none
of the phosphorus. compound. An analysis of,
the deposits indicates appreciably lesslead, bro 50
mine, chlorine and sulphur in engine deposits ob
'
I
Phosphorus __do____
Lead _______ __do____
55. 0
_
Pistons
48.8. I
7
-
per
,
Heads .
30.5
l6. 1
7. 9
gaso'
cc.-
-
gal: mb-utylphos'
' Pistons
54.7
1.4
0.5
have been run on leaded-fuels containing rela
y
line+l.o
-
For example, tributyl phosphite is illustrative
temperatures of deposits from. the combustion
chambers of internal combustion engines which,~ 45.
11-e '
Fuel—-Ethyl gasoline
19.9
-
15. 7
2. 9
6. 2
6.3
1.5
0.2
1.3
3. 2
51. 0
52. l
7. 4
3. 1
A
1.3
2.5
I
48. 2
End ofsecond‘mow-nzile'test .‘ ‘i
r‘ icaiitlgoi 1
‘1'8 _
P
11
._
y
gaso'
lglgijwél
ropertesoi deposits
’
Car No. 2 '
Fuelallthyl gasoline
phospmte_
tained‘from engines run on leaded-fuels contain
Heads
I
Pistons
w
Heads
H
--
I
Pistons
ing the organic phosphorus compound than
wheretheorganic phosphorus compound is ab-- '
Weight ________ --grams_.
analysis:
sent. These results are indicated _ in Table .11 55 Chemical
Bromine.__per cent__
below which is based on combustion chamber de
Chlorine ____ _-do_-_.
Sulphur; ____ __d0.-_.
posits of a single-cylinder test engine.
TABLE II
'
'
’ Lead ________ _.d
,
Errscrs or THE Us]: or TRIBUTYL PHOSPHI'I'E IN THE
ENGINE
‘
>
‘
--
___.
<
.
9.8
.. 4.4
1. 1
-
" ' 2.9"
'
54.7
'
20.1v
f 73.2
28.2
7.2
‘15.8
> 9.1
2.8
1. 2
1.9
47.9.
,
-
_
8. 5,
'0. 9
'
.
Trace
‘
57.5
8.7
1. 0
"Trace
'
54.1
-It is iequallyimportant to note in Tablev IV
below the vrelative effects of these engine deposits
FUEL ON THE COMPOSITION or LEAD DEPosi'rs'rN
THE COMBUSTION CHAMBER or‘ A SINGLE-CYLINDER
Tns'r
Phosphorus;__do___.
. 58. 5
'
on the preignition tendencies of the two testcars.
'
There; they preignition tendency is vexpress'edin
Fuel used in producing‘
‘
Analysis
' ‘
u
3 cc. tributyl
.
’
engine deposit "
White Crown phosphite per
'
Ethyl gasoline gallon Ethyl
.' ' .' 1
>
gasoline
7.
'10
Bromine
,
Chlorine
7
~
Sulphur.
»
_
4. Phosphorus.
0. 5
0.5
6. 8
Lead: _______________ __
Ignition temperature ___________ __
2.4 .
142.6
>=
_ 1, 0504
termsof octane number of the fuelLWhich is-re
quired to suppress preignition‘ at a series of dif
ferent- speeds. /At 15 miles per. hour,‘ for" ex
ample, 1 cc. per gallon of tributyl phosphite' in
Vethyl'gasoline is equivalent to an in'creaseoi 4
octane numbers in the fuel rating. and 2 cc. per
gallon of tributyl phosphite- in ethyl gasoline is
"equivalent to an ‘increase of ,13~~o_ctane numbers
in the fuel rating.‘ Similar di?erencesgmay'fbe
I observed .at ‘the other speeds listedui'n Table
‘Finany; it should be noted that, when the com
2,405,560
5
bustion chambers were clean, no preignition could
be observed in these cars even though they were
run under severe knocking conditions on 40
octane-number gasoline.
'Ifributyl phosphite is readily available com
mercially and is illustrative of a phosphorus
containing compound that has proven effective
in greatly reducing preignition in using leaded
gasolines as a fuel in spark-ignition internal com
TABLE IV
bustion engines.
EFFECT or TRIBUTYL PHOSPHITE ON THE PREIGNI
TIoN TENDENCIES OF TEST CARS AFTER 3,000
MILES OF AVERAGE OPERATION
End of ?rst 8,000-mile test
compound having su?icient solubility and being
10 su?‘iciently volatile will accomplish the desired
result.
Speed, miles per hour
Car No. 2
Car No. l
number of
Octane number of Octane
fuel required to
fuel required to
stop preignition,
stop preignition,
no additive
égeca/gs'l' mm‘
77
83
83
83
71
79
79
77
No'rE.-Neither one of these cars
74
____________ -_
74
____________ __
4% oeililane speeds below 40 miles per hour with clean combustion
0 am ers.
I believe that I am the ?rst to have
discovered the effect of phosphorus-containing
compounds in leaded-gasolines in order to pre
vent or suppress preignition in spark ignition
engines and it is desired to cover such discovery
in broad terms.
The invention is useful, also, in combating pre
ignition in gasolines which have not been treated
with lead but which may preignite due to the
presence of lead compounds in the combustion
chamber acquired previous to the use of the non
leaded fuel.
I claim:
2'0acfd§?€ega1' No additive
A leaded-gasoline for use in spark-ignition in»
ternal combustion engines containing a small
Less than 65
89 25
amount of a tributyl phosphite, said small amount
74
87
74
83
being not greater than about .1% of the fuel
by volume.
71
79
JOHN M. CAMPBELL.
30
would preignite on gasoline of
End of second 3,000-mile test
Speed, miles per hour
Other phosphorus-containing
compounds have been tested and found to be
effective. It is contemplated that any phosphorus
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