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Masters Theses
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1949
Water injection in the modern automotive spark
ignition engine
Leonard Carl Nelson
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Department: Mechanical and Aerospace Engineering
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Nelson, Leonard Carl, "Water injection in the modern automotive spark ignition engine" (1949). Masters Theses. Paper 6801.
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i
WATER INJECTION IN THE MODERN AUTOMOTIVE
SPARK IGNITION ENGINE
BY
LEONARD C. NELSON
A
THESIS
submitted to the faculty of the
SCHOOL OF MINES AND METALLURGY OF THE UNIVERSITY OF MISSOURI
in partial fulfillment of the work required for the
Degree of
MASTER OF SCIENCE, MElJHANICAL ENGINEERING MAJOR
Rolla, Missouri
1949
1i
ACKNONLEDGEMENTS
The author is indebted to Dr. A. J. Miles for his guidance and
timely suggestions during the course of this investigation, and t.
the students who assisted in oonducting the tests.
iii
CONTENTS
Page
Acknowledgements •••••••••••••••••••••••
ii
List of illustrations ••••••••••••••••••
iT
List of tables •••.••.••••••••••••••••••
T
List of plates (graphs) ••••••••••••••••
vi
PART I
Introduction•• ~ .•••••••••••••••••••••••
1
PART II
Teat equipment .••.•••.••.•.••••.•••••••
6
PART III
Test procedure •••••••••••••••••••••••••
9
PART IV
Interpretation of test results •••••••••
14
PART V
Conclusions •.•.••.••...•...•.....•..••.
42
Bibliography •••.•••••••••••••••••••••••
43
Vi ta ............••.•......•..........•.
44
iT
LIST OF ILLUSTRATIONS
rig.
Page
1.
Photograph of test equipment •••••••••••••••••••••••••••••
12
2.
Photograph of water injection system•••••••••••••••••••••
13
v
LIST OF TABLES
Table No.
Page
1.
Performance data for aviation gasoline •••••••••••••••
18
2.
Performance data tor regular gasoline (J) ••••••••••••
20
3· Performance data for regular gasoline (A) •••..••••••• 22
4.
Performance data for regular gasoline (B) ••••••••••••
24
5. Performance data for regular gasoline eC) •••••••••••• 26
6.
Performance data for regular gasoline (D) ••••••••••••
28
1-
Performance data tor regular gasoline (E) ••••••••••••
30
8. Performance data for regular gasoline (F) •••••••••••• 32
eG) ••••••••••••
34
10.
Performance data for regular gasoline (H) •••.••••••••
36
11.
Pertormance data for regular gasoline (I) •••...•.•.••
38
12.
Performance data tor regular gasoline (J) ••...••••.••
40
9-
Performance data for regular gasoline
vi
LIST OF PLATES
Plate No.
Page
1.
Octane utilization••••••••••••••••••••••••••••••••••••
11
2.
Performance curves (87 octane gasoline) •••••••••••••••
19
3·
Performance curves for regular gasoline (J) •••.•••••••
21
4.
Performance curves for regular gasoline (A) •••••••••••
23
5. Performance curves for regular gasoline
(B) •••••••••••
25
6. Performance curves for regular gasoline (C) ••••••••••• 27
7. Performance curves for regular gasoline (D) ••••••••••• 29
8. Performance curves for regular gasoline (E) ••••••••••• 31
9.
Performanoe curves for regular gasoline (F) •••••••••••
33
10.
Performance curves for regular gasoline (G) ••..•..•..•
35'
11.
Performance curves tor regular gasoline (H) •••••••••••
31
12.
Performance curves tor regular gasoline (I) •••••••••••
39
13. Performance curves for regular gasoline (J) ••••••.••.• 41
PART I
INTRODUC TI ON
1
The injecti.on of water in the spark igniti.on engine is not new.
The
effect of humidity in the air on the performance of the spark ignition
engine probably initiated the early investigations.
The water vapor in
the inlet air decreases the speed of the flame front and necessitates
spark advance to assure maximum power and maximum efficiency.
Water par-
ticles in the air evaporate during the compressi0n and combustion of the
inducted charge and decrease the tendency of the engine to detonate.
These
effects are very evident when operating the spark ignition engine in a
moist atmosphere.
Water is not a foreign element to the internal combustion engine.
It can be easily shown that when one pound of a hydrocarbon fuel burns
more than one pound of water is formed in the combustion chamber.
average
Hie
molar ratio of all the hydrocarbons making up a gasoline is
approximately 2.12.
On the basis of complete combustion, the end pro-
ducts will be carbon dioxide and water.
we
The
Balancing the chemical equation
have~
(l)
Thus 1 mol of fuel
forrr~
1.06 mola of water.
1.125 pounds of water per pound of fuel.
On
a weight basis this is
This combustion water and any
injected water becomes superheated and passes out with the other exhaust
products as a vapor.
The fundamental reason for injecting water is to suppress
~onation.
The exact nature as to how this is accomplished is not definitely known,
but it is reasoned that the effect is due to the high heat of vaporization
2
of the water.
(1)
Detonation, according to Ricardo,(l) results from auto-
H. R. Ricardo and H. S. Glyde, The High Speed Internal Combustion
Engine, pp. 40-69.
ignition of the last part of the charge to burn.
normally at the electrodes of the spark plugs.
Combustion originates
The flame front of the
burning progresses across the combustion chamber at rates varying from
40 to 100 it/sec.
The rate is a function of these folloWing variables:
fuel air ratio, initial pressure, initial temperature, residual gases,
humidity, engine speed, compression ratio, and fuel composition.
The
high specific volume of the burned products tends to compress the mixture ahead of the flame front.
As a result 'of the compression, the
temperature of the unburned charge is raised.
If the temperature of
the unburned charge is raised above its self-ignition temperature, the
entire unburned charge will spontaneously ignite.
Once a fuel reaches
its self-ignition temperature, a certain amount of time elapses before
ignition takes place.
The delay period is a function of the fuel com-
position, fuel air ratio, and temperature.
Although the fuel is above
its self-ignition temperature, this delay period may allow the flame to
pass through the unburned charge without detonation taking place.
If
the water acts only as a coolant, then water should affect all gasolines,
with the same octane number, alike.
When the water is inducted into the cylinder in a vapor state, it
reduces the volumetric efficiency of the engine considerably.
The specific
volume or the vapor at 80 0 r is 30,000 times as great as the specific volume ot the liquid.
If the water inducted is in the vapor state, it pro-
vides no cooling, and hence no adTSntage can be claimed.
The heat from
3
the charge necessary to vaporiz. the liquid water that is taken into the
cylinder becomes unavailable since the temperature of the gases on the
expansion stroke never drope below the condensation temperature of the
water.
The work from the superheated steam that forms from the heat
exchange between the hot gases and the water caD not be equivalent to
the work from the combustion products due to the irreversibility of the
heat exchange process.
With the aboTe in mind, it is evident that water
or water vapor inducted into the engine will lower the output of the
engine if the fuel air ratio, compression ratio, or spark advance remains the same.
Detonation in a spark ignition engine can be controlled by varying
the fuel air ratiG.
is the greatest.
At the beet power mixture the tendency to detonate
MOst aircraft engines control detonation by increasing
the fuel air ratio (rich mixture).
Decreasing the fuel air ratio (lean
mixture) would arrive at the same results with more economy but because
a lean mixture burns slowly, the engine would tend to heat.
To develop
the War Emergency Power Rating established by the Army and Navy for the
military aircraft without water injectioJl, it was necessary to enrich the
mixture beyond "best power mixture" to supress detonatien.
injectian the mixture could b. leaned
sulting in
8
t~
With water
the "best power mixture," re-
gain over that power developed using the rieh mixture with-
out water injecti~n.(2)
(2)
Paul F. Adair, Low Octane Fuel Plus Water Equals High Engine Performance, Aviation Maintenance, Vol. 1, pp. 43-45, February, 1944.
Detonation can be controlled by reducing the compression ratio.
4
Lower compression ratios result in lower temperatures after compression,
and also lower temperatures of the last part of the charge to burn.
This
in turn increases the ignition lag and allows normal combustion to take
place.
The equation for the efficiency of the theoretical spark ignition
Otto engine is
where
1
N
=1
r
=compression ratio
k
= adiabatic
-
(2)
rk _ 1
coefficient
It is evident that reducing the compression ratio cuts down on the .fficiency of the engine and the work output.
Water injection will allow
the use of the higher cODlpression ratio with a corresponding increase in
efficiency.
In the automobile engine today detonation is controlled to a great
extent by spark timing.
The compression ratio is considerably greater
than that ratio which would allow the correct spark advance for maximum
power using the regular fuels available.
engine operates at a reduced spark.
Hence, at full throttle the
Water injection allows the spark
to be advanced to the optimum position.
Thus, more power, better economy,
and cooler exhaust valves result.
Mr. Wm. M. Holliday's tests(3) on a 1948 car with a compression ratio
(3)
Wm. U. Holliday, Progress Report on the Duel-Fuel System, S.A.E.
Paper, June 6-11, 1948.
of 7.0 to 1 shows that even under adverse conditione the engine could have
been operating 80 per cent of the time knock-free with a 50 octane fuel.
Hence, it is an economic waste to use high octane fuel during this 80
per cent of the time.
Water injection is one of the answers to the
solution of thi5 problem.
number about
15
Properly injected water could raise the octane
octane numbers (a solution of yater, alcohol and tetra-
ethyl lead could raise the octane number as high
This allows a
65
8S
34 octane numbers).
octane fuel to be used instead of 80 octane fuel.
The
water being injected only during that 20 per cent of the time When it is
needed.
Tests made by Thompson Products Corporation(4) have shown that no
(4)
Alcohol Water Injection, S.A.E. Transactions, Vol. 53, pp. 359-
372, 1945.
more than normal wear results from water injection.
The corrosive wear
of the water injected is no more than that wear from the water which
fcrroB as a product of combustion.
The engine deposits ere about the
same, except they are softer and easier to remove.
Since 90 per cent
of the maintenance trouble in the internal combustion engine is due to
high temperature, it is apparent that water injection will result in
lower maintenance expenditures.
MOst commercial brands of fuels come from different wells, resulting
in a wide variation in fuel composition.
It is therefore proposed in
this investigation to determine if water injection affects different
brands of gasoline, with similar octane ratings, alike.
PART II
TEST EQUIPMENT
6
These tests were performed using a 1940 automotive engine.
Number of cylinders
Compression ratio
Bore and stroke
Head design
••••••••• 6
••••••••••• 6.8-1
••••••••••••• 3t x 4-3/8
••••••••••••••••• valve-in-block
Rated horsepower
•••••••••••• 91 @ 3800 rpm
The distributor of the engine was of the automatic advance type.
At
full throttle the centrifugal mechanism advanced the spark approximately
two degrees for an increase in speed of 250 rpm.
During part-throttle
operation, the vacuum mechanism advanced the spark beyond the advanc.
of the centrifugal device.
Provision was made to advance the spark
manually by rotating the distributor body counterclockwise relative to
the engine.
The regular Stromberg fixed-jet carburetor was used.
The air-
bleed jet maintained lean mixtures during part-throttle operation, and
the power jet maintained rich mixtures at wide open throttle.
The engine was directly coupled to an electric dynamometer supported
on ball bearing trunions.
A beam scale was used to measure the turning
force exerted by the stator of the dynamometer.
A counterbalance was
attached to the dynamometer to eliminate the tare weight correction.
The dynamometer could be used either as a motor to turn the engine or
as a generator to absorb the power.
An electric tachometer was used to measure the rpm.
calculated from
~he
folloWing equation:
Horsepower was
7
B.H.P.
= KFN
K
=dynamometer
F
= force
where
constant
= 1/3000
on the scale
N = R.P.M.
A balance scale was used to measure the fuel consumed.
was electrically connected through a mercury switch to
8
The scale
revolution
counter.
This counter gave the number of revolutions to burn one pound
of fuel.
The following equation was used to figure the brake specific
fuel consumption:
B.S.F.C.
K'
=FxR
~--~
= force on the scale
R = number of revolutions
where
F
K' - weighing device constant
=180,000
A commercial water injection device was used to inject the water
into the engine.
The water injector was mounted between the intake air
strainer and the carburetor.
The flow of water could be manually con-
trolled by adjusting a needle valve.
A differential in pressure between
the float chamber and the throat of the venturi forced the metered water
to enter the air stream.
The flow characteristics of the water injector
were similar to those of the carburetor, resulting in practically a constant water/fuel ratio.
The spark timing was measured, using a neon light.
The light was
located in a hole which was drilled radially in a bakelite disc.
A slit
opening to the hole allowed the glow from the light to make a fine indieating line on the face of the disc.
This assembly was mounted on the
8
centerline of the fly wheel.
A circular scale, calibrated in degrees,
was fixed to the engine at the periphery of the disc.
Thus, the indi-
cator line showed the position of spark in relation to top dead center.
The jumper from the coil to the distributor was made to pass close to
the periphery of the disc.
The leakage flux, during ignition of the
charge in one of the cylinders, was enough to energize the light.
This
device gave the position, with respect to the crank, at which all six
cylinders were sparking.
A Sperry gyroscope vibration pick-up was used to assist in indicating borderline-knock.
coil.
The pick-up housed a permanent magnet and a
It operates on the magneto-strictive principle Whereby physical
deformations set up in the magnetic path produce a flux change resulting
in a voltage being induced in the coil.
of the cylinder-head stud bolts.
It was mounted directly to on.
The fluctuating voltage was fed dir-
ectly into a Du Mont 208 oscilloscope.
Knock in one of the cylinders
would show up as a pip on the oscilloscope screen.
PART III
TEST PROCEDURE
9
A spark ignition engine will have maximum detonation occurring at
full throttle, all other variables remaining fixed.
For this reason
the comparison tests of the various gasolines were run at wide open
throttle, variable speed.
Detonation was determined in most cases by ear in conjunction with
the vibration pickup.
The knock intensity was maintained constant at as
Iowa value as was clearly perceptible to the ear.
This is often referred
to as "trace-knock" or "borderline-knock" conditions.
The instrumentation
knock detection set-up is usually not as successful as detection by ear,
since the sensitiTity of the instrumentation varies with operating conditions.
Noise from the engine did not interfere in the detection of
the characteristic knock sound at most speeds.
However, 1000 rpm was an
exception to this, since this was one of the critical speeds for the unit.
The cooling water leaving the engine was held at approximately l75°F
by manually regulatinc the inlet control valve.
To maintain this temp-
erature, it was necessary to vary the valve setting at the beginning of
each speed run.
Although no attempt was made to control the temperature of the lube
oil, no test was started before warming up the engine.
Tests were begun
When the lube oil had reached a temperature of 150 0 F.
The engine was operated, using a high octane aviation gasoline, to
determine the effect of spark advance on performance.
To assure that no
detonation would occur, regardless of spark advance, one gallon of i80octane was added to two gallons of the aviation gasoline.
The engine was
run at a constant speed at 1250 rpm with the throttle fully open.
A
10
complete set of readings were taken at each different setting of the
spark.
The spark was advanced until a definite break was evident iR
the B.S.F.C. and the B.H.P.
To assure the same barometric condition, the comparison tests on
each fuel were conducted during the same evening.
Ten different brands
of fuels were used for these comparison tests.
Nine of these were regular
fuels whose octane rating varied only slightly.
One fuel was high-test.
In all cases the engine was first run with no water being injected.
engine was loaded down until the speed was 750 rpm.
temperature was adjusted to 175°F.
The water outlet
Then the spark was advanced until a
borderline or trace-knock condition prevailei.
locked at this position.
The
The distributor body Yas
The oentrifugal or Mfly ball" advance held the
spark to this borderline-knock position throughout the speed range.
speed increased at intervals of 250 rpm up to 2500 rpm.
The
The length of
each run was the l.ngth of time necessary to consume the one pound of
fuel on the balance scal..
two minutes.
The interval between runs was approximately
This time was necessary to fill the beaker on the balance
scale with the fuel for the next run.
were taken during each speed run.
Three readings of all variables
The aTerage of these was reported.
Immediately following this series of runs, the engine was tested
with water being injected.
at 750 rpm.
The amount of water to inject was determined
The rate of water flow was varied until the maximum spark
advance could be realized with a minimum amount of water.
More water
than this minimum amount simply decreased the output of the engine.
The
distributor body was locked at this advanced "borderline-knock" spark
setting.
The "fly-balls" advanced the spark beyond this original .etting
11
as the speed increased.
As before, runs were made at intervals of 250
rpm up to a speed of 2500 rpm.
As a result of engine failure during these series of teats, the
engine was given a minor overhall job.
Carbon was removed from the
combustion elmmber, intake and exhaust valves were ground, and the old
spark plugs were replaced.
This eliminated the ttmiss" which started
during Run No. 2 at the high speeds.
PA.llT IV
INTERPRETATION OF TEST RESULTS
12
....•
13
Fig. 2.
Photograph
or
water injection system.
14
It was stated in the introduction that most automotive spark ignition engines operate at a reduced spark when using regular fuels to
suppress detonation.
Plate 2 shows the increase in output and efficiency
which could be realized it the octane rating ot the tuel were high enough
to allow the spark to be advanced.
A comparison with the maximum spark
setting for the other regular fuels reveals that at 1250 rpm, the aver0
age apark advance is 6 before top dead center.
Plate 2 shows that the
optimum spark position for this engine should be 14 0 or more before top
dead center.
Using a 6° spark advance, the B.R.P. is 33.89 and the B.S.F.G.
is 0.591.
At a 14° spark advance, the B.R.P. is 34.45 and the B.S.F.C.
is 0.570.
This represents a 1.6% gain in B.R.P. and a 3.55~ gain in
fuel economy.
Thus, it is possible to obtain more horsepower and lower
fuel consumption if some means are provided to increase the octane rating
of the regular fuels.
The performance curves for the different gasolines, With one exeepti$n, showed more favorable results without water injection.
One
reason for this i. the rich mixture whioh was supplied at full throttle.
No attempt was made to lean the mixture for tear of damage to the exhaust
valves.
Although uneconomical, using a rich mixture is one method to
suppress detonation.
mized.
Hence, the effects of water injection are mini-
Also, it tuels with lower octane ratings or an engine with a
higher compression had been used, the results would have been more ia
favor of water injection.
the regular fuels.
The engine used was designed to operate on
The spark advance was set at 150 rpm, b cause at
this low speed it wae the easiest to detect detonation.
At this speed,
15
however, the distribution of fuel air and water in the inlet manifold
is relatively poor.
centage of water.
Hence all cylinders did not receive the same perSpark was advanced until one of the cylinders knocked.
This poor distribution did not sssure the maximum spark advance at all
Reference to Plate 3 shows this very clearly.
speeds.
If the spark is
advanced at 1250 rpm, the performance is considerably poorer than when
the spark was advanced at 1500 rpm.
However, it was felt that since
this thesis was to determine the relative etfects of water i_jection on
different gasolines, the afore mentioned would not distract from the
value of the tests.
The performance curves on Plate 13 were obtained before the engine
failure.
It is interesting to note that here the BHP and BSFC were
much better with water injection.
this.
There are two plausible reaSons for
First, when the engine Was overhauled, all carbon and products
of combustion were removed from the combustion chamber.
These deposits,
although small, would cause a noticeable increase in the compression
ratio of the engine.
To keep away frem detonation without water in-
jection, the spark would have to be retarded a number of degrees.
The
effects of water injection under this condition are more pronounced.
Second, the strainers in the fuel system were thoroughly cleaned.
dirty strainer may have caused a decrease in the fuel-air ratio.
A
Sinee
a lean mixture is more susceptible to detonation, a retarded spark is
necessary.
For this reasoh, also, the effects of water injection would
be more pronounced.
As shown by Plates 4 and 8, gasolines A and E vary the most from
16
the performance curves of the other gasolines.
may have partly caused this.
The humidity of the air
As a Whole, it appears that water injection
affects all gasolines of approximately the same octane rating alike.
TABLE I
Gasoline - Aviation
87 OCtane
Wet bulb temperature - 70°F
Dry bulb temperature - 790F
RPM
Barometer - 29.02" Hg.
March
28, 1949
Constant at 1250
Spark
Water in, OF
Water out, OF
Air, OF
Oil, OF
Torque #
Fuel #
Rev. xlO
5.,
16
175
89
170
81.1
1
373
7.5
75
175
90
172
81.9
1
316
9.,
75
175
90
113
82.2
1
378
12.0
75
175
88
173
82.5
1
379
14..5'
74
175
90
174
83.0
1
378
16.0
74
175
90
114
82.4
18.0
73
175
90
156
82.1
1
1
380
389
20.0
14
175
89
163
81.6
1
390
I-'
00
19
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TABLE II
Gasoline J
Wet bulb temperature - 70°F
Dry bulb temperatu~e - 80 0 r
March 23, 1949
Barometer - 28.6" Hg.
Without Water
6.0
1
369
71
115
90
182
81.1
8.5
1
378
1'150
70
175
92
182
80.0
9-5
1
376
2000
70
175
90
185
79.2
11.0
1
378
2250
70
175
91
190
78 ....
13.5
1
379
1500
70
175
90
196
81.7
8.5
1
371
34.3
0.597
40.5
0.587
46.7
0.598
52.8
0.601
58.6
0.612
40.8
0.594
75
175
87
160
80.6
12.0
73
71
175
91
182
78.3
70
175
90
192
81.2
1105
1605
372
150
2'11.6"
75
1'15
87
168
80.3
13.0
1
372
150
1'49.8"
33.6
0.601
0.448
40.2
0.6040.435
RPM
Water in, or
Water out, Or
Air, or
Oil, 8r
Torque #
Spark
Fuel #
Rev.
12,0
71
175
92
186
BHP
BSFC
0
Water in, F
Water out, OF
Air, OpOil, OF
Torque #
Spark
Fuel #
Rev.
Water (grams)
Time
BHP
BSFC
#~O/# fuel
82.2
1
1,00
With Water
15.0
1
370
150
1'34.5"
12
175
89
178
79.1
16.0
1
376
150
1'24.9"
1
373
150
1'14.6"
46.4
0.614
0.442
52.7
0.606
0.438
58.7
0.617
0.446
175
87
170
7905
1
372
1150
2000
70
175
89
190
10
175
88
190
79.6
80.2
18.0
1
370
20.0
1
380
2250
70
175
89
192
78-5
21.0
1
310
Same as berere
40.6
00596
0.43.5'
46.8
0.607
0.442
53.1
0.596
0.438
58.8
0.622
0.446
1'0>
0
21
TABLE ,III
Gasoline A
W.t bulb temperature Dry bulb temperature -
64 0 r
67&r
Barometer -
29.32"
March
Hg
15, 1949
Witbout Water
RPM
Water in, of
Water out, Or
Air, OF
Oil, OF
Torque #
Spark
Fuel #
Rev.
17,0
66
175
80
174
80.9
8.0
1
369
2000
66
175
80
174
80.6
1
368
1500
67
175
74174
81.8
6.0
1
371
1000
67
175
73
18,
83.8
3.0
1
368
12;0
175
72
179
82.5
67
405
27.'
Bsre
00584-
34.4
0-5'93
40.8
0-5'93
47.1
0.603
Water in, OF
Wster out, Or
Air, OF
Oil, OF
Torque #
Spark
Fuel #
Rev.
Water (grams)
Time
67
17,
65
1;0
83.1
61
175
65
150
80.8
61
175
66
154
79.9
9.5
67
175
75
157
79.9
11.0
BlIP
BHP
BSFC
#H2 0/# fuel
605
1
361
100
l' 22.s"
27.7
0.600
0.5'91
805
2$00
66
115
78
188
78.5
13.0
1
369
,3.7
0.610
59.9
0.614
65-5'
0.621
66
175
78
166
80.2
12.0
1
370
150
0'58.8"
67
175
81
180
79.8
14.0
1
367
250
1 1 37.3"
67
175
78
18477 ,9
16.0
5305
59.8
0.614
65.0
0.624
00550
00.5'00
905
With Water
1
369
100
1'10.6"
1
1
374
100
371
100
0'53.2"
33.6
0.604
40.0
0.603
00550
00545
1'Q:t"
1
366
22;0
66
115
78
180
79.9
11.0
1
367
46.6
0.606
0.527
0.606
0.628
1
370
200
l'18.8 t1
N
N
23
TABLE IV
Gasoline B
Wet bulb temperature - 640F
Dry bulb temperature - 70 0 r
RPM
Water 1n, of
Water out, or
Air, of
1000
71
172
Oil, OF
Torque #
Spark
Fuel #
Rev. x 10
Barometer - 29.09" H!.
188
82.8
5.0
1
359
12,0
71
174
84
180
81.7
6.0
1
3;7
1,00
70
170
86
180
80.6
7.5
BHP
BSFC
27.6
0.605
34.1
0.617
40.3
0.613
Water in, OF
Water out, OF
Air, OF
Oil, OF
Torque #
Spark
Fuel #
Rev. x 10
Water (grams)
74
170
82
140
80.7
9.0
1
359
150
2'9.6"
72
170
81
142
79.6
10.0
1
364
150
1'46.6"
72
172
83
150
78.8
1105
1
362
150
1'28.7"
26.9
0.621
0.;88
33.1
0.621
0.543
39.4
0.631
0';38
Time
BHP
BSFC
#I1I;.0/# fuel
8S
1
364
Without Water
2000
17;0
70
70
172
172
87
89
180
180
80.0
79.8
11.0
9.;
1
1
367
365
46.6
0.613
With Water
71
172
84
158
78.;
13.5
1
363
100
0'5;.3"
45.8
0.631
0.496
March 16, 1949
22,0
70
172
87
188
79.0
12.5
1
369
2,00
68
172
87
192
77.4
14.0
1
373
53.2
0.618
59.3
0.617
64.;
0.622
71
1'1485
170
78.7
15.0
1
362
150
1'7.6"
70
172
86
178
78.1
17.0
1
362
150
1'0.3"
70
112
87
186
76.6
19.0
1
367
150
0'58.8".•,
52.5
58.6
0.636
0.$31
63.8
0.640
0.530
0.631
0.$89
....
I\)
TABLE V _
Gasoline C
Wet bulb temperature - 64 0 r
Dry bulb temperature • 10°F
Barometer - 29.09 tt Hg.
Without Water
1750
69
170
8.5'
180
80.2
9.5
1
367
RPM
Water in, of
Water out, OF
Air, of
Oil, or
Torque #
Spark
Fuel #
Rev. x 10
1000
70
170
8.5'
186
83.1
.5'.5
1
362
12.5'0
70
170
86
180
82.0
6.;'
1
367
1500
70
170
8.5'
118
80.8
8.0
1
370
SHP
BSFe
27.6
0.605
34.1
0.617
Water in, or
Water out, OF
Air, OF
Oil, OF
Torque #
Spark
Fuel #
Rev. x 10
Water (grams)
70
168
85
180
81-.5'
10.0
1
350
150
2'10.1"
70
110
85
174
80.0
1
360
1.5'0
1'45.7"
46.6
0.613
With Water
70
70
170
170
85
85
174
116
79.7
79.0
12-5
14.0
1
1
358
359
150
100
1'25.8"
0'50.5"
27.2
0.630
OS33
33.4
0.625
0-.5'38
39.9
0.631
0-.5'49
Time
BHP
BSFe
#H20/# fuel
lIS
40.3
0.613
46.1
0.634
0-542
March 16, 1949
2000
69
172
8.5'
182
7905
11.0
1
368
22.5'0
68
171
87
188
7805
13.0
2500
68
172
86
194
77-5
15.0
I-
I
367
371
53.2
0.618
59.3
0.617
6405
0.622
70
169
89
180
79.2
16.0
1
357
150
1'8.2"
70
172
89
184
7805
18.0
1
359
150
1'0.0"
69
170
89
190
76.5
19-5
1
363
150
0'54.4"
52.8
0.637
00581
58.9
0.638
0.5'27
63.8
0.648
0.5'28
f\)
0'
TABLE VI
Gasoline D
Wet bulb temperature - 10°F
Dry bulb temperature - 800r
RPM
Water in, Or
Water out, Or
Air, OF
Oil, OF
Torque
Spark
Fuel
II
II
Rev. x 10
BHP
BSFC
Water in,
Water out,
Air, or
Oil, OF
Torque #
Spark
Fuel #
0
r
or
Barometer - 28.61" Hg.
Without Water
1000
70
175
87
188
82.7
8S
1
359
1250
69
175
84
182
80.7
9.0
1
382
1500
69
175
84
118
79.6
10.0
1
382
1750
69
175
86
178
79.0
12.0
1
380
2000
69
175
85
180
78S
14.0
1
378
2250
68
175
89
182
77.5
15.0
1
376
2500
68
175
89
188
75.5
17.5
1
379
27.6
0.606
33.6
00583
39.8
00591
46.1
52.3
0.606
58.1
0.617
62.9
0.629
69
115
84
168
80.8
10.0
1
70
175
82
162
79.1
70
175
86
164
78.4
13.0
1
317
150
1'49.1"
70
115
85
166
77 .8
14.0
1
374
150
1'34.1"
69
175
85
170
77.4
15.0
1
3'12
150
1'25.3"
69
175
176
76.8
17.5
1
378
150
1'13.3"
69
175
89
184
74.5
20.0
371
150
1'7.2"
45.4
0.618
0.450
51.6
0.62;
0.431
57.6
0.623
0.451
62.1
0.6;1
0.483
lIS
376
Water (grams)
Time
150
2'33.1"
1
380
150
2'13.3"
BHP
BSFC
26.9
0.592
0.494
OS98
Rev. x 10
#H2 0/# fuel
March 21, 1949
33.0
0.455
39.2
0.609
0.456
OS99
With Water
86
1
I'\)
00
TABLE VII
Gasoline E
Wet bulb temperature - 62°'
Dry bulb temperature - 730F
RPM
Water in, or
Water out, or
Air, or
Barometer - 28.94" Hg.
1000
69
175
18
176
83.3
. 6.0
1
369
1250
67
175
18
112
81.3
6.5
1
386
Torque #
Spark
Fuel #
Rev. x 10
7,0
68
175
87
188
80.2
0.0
1
385
BHP
BSFC
20.0
0.584
27.8
0.586
33.8
0.573
Water in, or
Water out, OF
Air, OF
Torque #
Spark
Fuel #
Rev. x 10
Water (grams)
Time
68
175
80
113
75.8
2.0
1
394
100
2'36.5"
70
175
18
167
80.7
8.0
1
369
150
2'13.8"
68
115
81
164
78.5
9.0
BHP
19.0
26.9
0.605
0-546
32."
0.605
0-571
Oil,
or
Oil, of
BS~
#H2 0/# fuel
0.602
0.454
Without Water
1500
68
175
78
110
80.4
7.0
1
386
1
379
150
1'45.0"
40.2
0-580
With Water
68
175
80
166
78.0
10.0
1
370
150
March 17, 1949
17,0
66
175
82
172
79.5
9.0
1
384
2000
61
175
79
172
79.6
12.0
1
381
22,0
66
175
80
180
78.8
13.0
1
371
2,00
66
175
80
186
17.3
15.0
1
318
46.4
0.590
53.1
0.593
59.1
0.605
64.4
0.616
68
175
77
168
68
175
80
110
77.9
13.0
1
365
67
175
79
176
77.2
15.0
1
364
150
77.6
11-5
1
370
150
1'28-5"
1'17.2"
39.0
0.624
0.552
45.3
0.626
0.542
1'7.7"
1'0.5"
66
115
83
184
75.9
17.0
1
368
150
0'55.3"
51.9
0.634
0-535
57.9
0.640
0-534
63.2
0.644
0-527
150
w
0
TABLE VIn
Gasoline F
Wet bulb temperature - 62°F
Dry bulb temperature - 130F
Barometer - 28.94" Hg.
March 17,
1~49
Without Water
1000
69
115
76
150
83.0
4.0
1
372
12;0
69
175
Rev. x 10
1;0
67
175
16
152
77 .1
1.0
1
403
BliP
B5FC
19.3
0"78
Water in, or
Water out,
Air, OF
Oil, OF
Torque, #
Spark
Fuel, #
RPM
Water in, or
Water out, of
Air, of
Oil, or
Torque, #
Spark
Fuel,
#
0,
Rev. x 10
Water (grams)
Time
BlIP
BSFC
#H20/1! fuel
152
81.2
6.0
1
376
1500
68
175
79
1;6
80';
7';
1
377
1750
68
175
79
162
80.2
9.0
1
376
2000
66
175
79
166
79.8
10';
27.7
0.,83
33.8
0.;90
40.2
0';93
69
175
80
184
76.7
4';
1
392
100
2'28.4"
70
175
82
172
81.8
9.0
1
367
150
2'16.8"
69
175
83
166
80.4
11.0
1
369
150
1'46.9"
68
175
79
169
79.7
13.0
1
363
150
1'28.9"
19.0
0.599
0.466
27.3
0.600
0.,31
33"
0.607
0.54;
39.8
0.622
0.537
71
370
2250
66
175
79
174
79.2
12"
1
372
2500
66
175
83
184
71.1
15.0
1
371
46.8
0"96
53.2
0.610
59.4
0.610
64.2
0.624
68
175
78
172
79.0
68
175
1
366
150
1'17.;"
176
79.0
15.5
1
363
150
1'8.8"
66
175
80
184
78.2
17.0
1
362
150
1'1.4"
66
175
85
184
76.2
20.0
366
150
0'".4"
46.1
0.623
0';32
52.6
0.628
0';22
58.6
0.635
0';20
63.5
0.64;
0';25
With Water
1405
1
80
1
wf\)
TABLE IX
Gasoline G
Wet bulb temperature - 72°F
Dry bulb temperature - 76.5 0 F
RPM
Water in, of
Water out, of
Air, of
Oil, of
Torque #
Spark
Fuel fI:
Rev. x 10
1000
70
17;
89
186
83.7
;.0
1
3'13
BHP
BSFC
Water in, OF
Water out, OF
Air, OF
Oil, OF
Torque #
Spark
Fuel #
Rev. x 10
Water (grams)
Barometer - 29.00" Hg.
1250
73
175
87
184
81.3
1500
70
175
88
182
1
382
27.9
0.;77
16
17;
8;
;7.0
0.623
61.1
0.638
72
175
88
71
175
88
176
76.2
14.0
34.0
0';81
40.1
0.;86
46.2
0.;89
73
175
85
1;6
78.9
9.0
1
376
1,0
1';0.2"
72
175
81
162
79.0
10'"
1
317
39';
0.607
0.450
BHP
27.3
0';95
0.423
33.1
0.608
0.400
#HZO/# fuel
51.7
0.613
8S
1
382
;.;
2';2';"
BSFC
2500
70
175
89
192
73.2
15.0
1
38;
70
175
88
183
77.5
11.0
Time
140
379
70
175
90
186
76.0
12';
1
380
70
115
88
180
79.3
9';
1
380
74
175
83
150
79.4
7.0
1
373
150
2'14.8"
81.8
6.0
1
370
150
Without Water
2000
1750
80.3
March 22, 1949
1
With Water
22;0
1'34.2"
78.6
12.0
1
372
1,0
1'24.8"
370
1,0
1'1;.2"
10
175
87
186
74.6
17.0
1
360
1,0
1'8.2"
46.1
0.604
0.452
52.40.616
0.434-
57.3
0.640
0.432
62.2
0.671
0.403
ISO
170
1
w
~
35
TABLE X
Gasoline H
Wet bulb temperature - 72°F
Dry bulb temperature - 76.5°F
RPM
Water in, of
Water out,
Air, of
Oil, of
Torque :#
0,
Spark
Fuel
#
Rev. x 10
BHP
BSFC
0
Water in, F
Water out, of
Air, of
Oil, OF
Torque
#
Spark
Fuel #
Rev. x 10
Water (grams)
Time
BHP
BSFC
#H2 0/
lf
fuel
1000
72
175
90
190
84.9
5.0
1
363
1250
72
175
86
186
81.4
5.0
1
383
1,00
70
175
85
184
80.5
7.0
1
379
28.3
0.584
34.0
0.573
40.2
0-590
70
175
89
182
82.0
8.0
1
372
150
2'27 .2"
70
175
86
176
80.3
10.0
1
376
150
2'14.8"
70
175
87
176
79.4
11.0
1
374
1,0
1'49.9"
27.4
0"90
33.5
0.596
0.442
39.7
0.608
0.448
00501
March 22, 1949
Barometer - 29.00" Hg.
Without Water
2000
1750
70
10
175
175
86
87
181
184
80.1
79.5
10.0
9.0
1
1
376
375
46.7
53.0
0.597
0.603
With Water
70
71
115
175
90
89
176
175
78.,
79.2
12.0
14.0
1
1
372
369
150
150
1'34.0" 1'23.0"
46.3
- 0.611
0.448
52.3
0.622
0.439
2250
70
175
86
186
78.7
12.0
1
377
2500
69
175
86
192
76.6
14.0
59.2
0.606
63.9
0.639
70
175
90
182
77.8
16.0
1
369
150
1'14.3"
70
175
90
188
76.2
17.,
1
372
150
1'7.0"
58.3
0.628
0.438
0.634
1
377
63.4
0.442
w
0'
TABLE XI
Gasoline I
Wet bulb temperature - 70°'
Dry bulb temperature - 80 0 r
Without Vlater
RPJ4
Water in, °,
Water out, OF
Air, or
Oil, of
Torque
Spark
Fuel
Rev.
150
65
175
88
187
77.9
2
1
394
1000
71
175
85
174
82.0
7
1
368
1250
6,
175
84
168
80.1
8
1
379
BHP
BSFC
19.4
0.586
27.3
0.595
33.4
0.591
Water in, of
Water out, OF
Air, eF
Oil, of
Torque
Spark
Fuel
Rev.
Water (grams)
Time
70
175
82
152
17.4
7
1
390
150
4'21.1"
72
175
85
152
79·2
11
115
88
153
8
1
383
150
2'59.6"
9
1
379
150
2'11.0"
BHP
19.3
0.596
0.395
26.3
0.592
0.42;
32.3
0.610
0.460
BSFC
#~o/# fuel
March 21, 1949
Barometer - 28.61
77.6
2250
69
175
88
179
77.7
2500
376
376
2000
69
175
88
175
18.2
12
1
372
39.6
0.598
45.9
0.607
52.1
0.618
58.3
0.600
70
115
86
158
76.9
10
1
380
150
10
175
88
163
77 .2
1'48.9"
12
1
383
150
1'34.3"
70
175
88
168
77.1
13
1
387
150
1'25.0"
69
175
87
175
76.4
15
1
363
150
1'16-5"
69
175
88
185
74.4
18
1
372
150
1'08.6"
38-5
0.615
0.460
45.1
0.60'/
0.460
51.4
0.602
0.451
57.1
0.650
0.418
62.0
0.650
0.430
1500
70
175
85
170
79.3
9
1750
69
175
84
172
78.8
11
1
1
With Water.
14
1
386
Vol
00
\.. I
~""":':".:.cL±:L;; I ·lJ
TABLE XII
Gasoline J
CD
W.t bulb temperature - 66 F
Dry bulb temperature - 82°F
Barometer - 28.84"
1250
72
176
97
18;
12S
381
390
1500
71
176
91
189
72.2
-0.,
1
397
BSFC
24.4
0.634
30.2
0.635
36.1
0.627
Water in, of
Water out, C7
Air, or
Oil, OF
Torque #
Spark
Fuel #
Rev. x 10
Water (grams)
73
176
93
164
18.3
11.5
1
313
150
13
176
91
169
78"
12.0
1
386
150
73
176
91
116
77.8
13.0
1
392
BHP
BSFC
26.1
0.616
32.7
0.,'4
Water in, of
Water out, of
Air, of
Oil, of
Torque #
Spark
Fuel II
Rev. x 10
BHP
-2"
1
-2"
1
1750
70
176
99
192
11.7
fuel
1,0
---
38.8
0';91
2000
10
1
399
176
98
191
12.2
3.0
1
401
41.9
0.628
48.2
0.624
1.0
With Water
#H.tz0/#
March ;, 1949
Without Water
1000
71
176
97
186
73.4
RPll
ag.
2250
70
176
99
204
57.2
5.0
1
390
2500
2750
10
176
96
205
13.5
22.5
13
176
91
181
76.8
15.0
1
388
1;0
12
176
91
189
76.5
18.0
1
384
11
176
96
197
75S
20.0
1
381
IS0
1;0
386
150
10
176
97
215
70.3
25.0
1
394
1;0
44.8
;1.0
0.613
56.6
0.616
61.4
0.635
0.650
0.604
Average 0.;40 ---
1
64-5
...
0
PART V
CON:LUSION5
42
It is the opinion ot the author, as a result ot this work, that
the etfects of water injection on the operation of a spark ignition
engine are mainly due to the coolant properties ot the water.
can be contrasted with
tetra~ethyl
This
lead which has negative anti-
detonate effects on some fuels and positive anti-detonate effects on
other fuels.
The lead acts chemically with the fuel to change its
self-ignition temperature.
The water,
8S 8
coolant, merely lowers
the combustion temperature so that the self-ignition temperature 1s
not reached.
This investigation indicates that for best results from water
injection, the fuel used should have a lower octane rating than that
required by the engine, and the mixture used should be at the best
power ratio ot fuel and air.
MOre tests should be conduoted with an engine with a variable
compression
rati~
to further establish the authenticity of the results
and conclusions of this thesis.
43
BIBLIOGRAPHY
1.
Books:
Fraas, A. P.
pp. 75-122.
CombustiQn engines.
N. Y., NcGraw-Hill, 1948.
Jennings, B. H., and Obert, E. F. Internal combustiQD engines.
Penn., Interaational, 1944. pp. 215-2~5.
JQst, W., and Croft, H. O. Explosion and combustion processes
in gases. N. Y., MCGraw-Hill, 1946. pp. 160-209.
Ricardo, H. R., and Glyde, H. S. The high speed internal combustion engine. London, Blackie and Son, 1945. pp. 40-69.
Taylor, C. F., and Taylor, S. T. The internal combustion engine. Penn., International, 1948•. pp. 87-119.
2.
Periodicals I
Adair, Paul F. Low octane fuel and water equal high engine
performance. Aviation Maintenance. Vol. I, pp. 43-45 (Feb.
1944)
Collwell, A. T., Cummings, R. E., and Anderson, D. E. Alcoholwater injection. S.A.E. Transactions. Vol. 53, pp. 258-272 .
(1945)
3.
UnpUblished Material:
Collwell, A. T. More effective utilization of high octane
fuels. Paper presented sept. 9, 1948 at 1948 National Tractor
and Diesel Engine Meeting of Society of Automotive Engineers,
!filwaukee, \fis.
Holliday, W. M. Progress report on the duel-fuel system.
paper. June 6-11, 1948.
Naval Air-Technical Training.
CA-1-231.
Aircraft water injection.
SAE
SB-
Rector, W. R. Description or Pratt and Whitney aircraft water
injection equipment for war emergency power. Report, P.W.A.,
Inst. 92. April 15, 1943. 20 pp.
Van Hartesvelt, C. H. Paper presented June 11, 1948.
Meeting S.A.E. French Lick, Ind.
Summer
44
VITA
The author was born August 26, 1920, at Albia, Iowa.
pleted his high school education at Albia, Iowa, in 1938.
He comHe at-
tended Albia Junior College for two years and then enrolled at Iowa
State College.
He graduated with a B. S. degree in Mechanical Engi-
neering from Iowa State in February, 1943.
Following graduation,he
accepted a job with Fisher Body Division of General Motors.
1943, he was called into service with the U. S. Navy.
June,
He served
88
a Naval Inspector of Machinery, Ship Superintendent, end Engineering
Officer.
Following an honorable discharge from the Navy, he returned
to Fisher Body on August 20, 1946.
a position as Instructor of
In February, 1947, he was offered
~chanica1
Engineering at the Missouri
School of Mines and Metallurgy, of which he accepted and has continued
to date, 1949.