Jan.,
1921
T H E JOURNAL OF INDUSTRIAL A N D ENGINEERING CHEMISTRY
aggregate of t h e fuel equivalent of gas and t a r saved, increased coke yield, and improvement in blast-furnace fuel efficiency. Ammonia and benzene recovery would be an additional gain. The conservation of coal by means of coking will grow as t h e outlet for coke and by-products grows. Extension in this field is not t o be considered as limited b y the metallurgical demand for coke. Coke and coke-oven gas as fuels, however, are likely t o meet strong competition eventually from cheap power developed in central stations and from lower-cost gas made b y complete gasification processes. C O T ~ L O I D A L FuEL-colloida1 fuel deserves mention in connection with fuel conservation. Colloidal suspensions of pulverized coal in oil permit of t h e same economies in application as either oil or powdered coal alone, and have some advantages, notably permitting t h e use of higher ash coals, higher sulfur oils, and many carbonaceous waste products, concentration of heating value in relation t o bulk, and decreasing of fire hazard as compared t o oil. It is of important bearing, however, on t h e probable future development of this new fuel t o consider t h e oil reserves available t o t h c United States for fuel purposes. SUMMARY
I n general, why is fuel conservation t o be needed when our transportation systems shall become equipped t o deliver what is required? I n t h e first place, efficiency in t h e use of raw materials makes for increased financial returns ; secondly, waste promotes extravagance and raises t h e cost of living; and lastly, our high-grade fuel reserves are being exhausted a t a n alarming rate. George H. Ashley, State Geologist of Pennsylvania, estimates' t h a t practically all of t h e easily workable coal beds of Pennsylvania, 6 f t . or more in thickness, will disappear in 7 5 t o 80 yrs. at t h e present rate of increase in exhaustion. Low sulfur coals for metallurgical purposes are becoming scarce, so much so t h a t steel men are investigating measures for gctting along without them. Yet t h e low sulfur Pocahontas and New River coals are still sold in large part for steaming purposes, where such low sulfur content is not a n essential quality. There is a progressive tendency, however, in America towards greater fuel economy, and future developments are likely t o decrease materially our per capita consumption. DISCUSSION
DR. PORTER:It will perhaps bear repetition €or the sake of
emphasis, that statistics show we are progressing remarkably well in economic utilization of coal, and this paper accordingly is not l o be taken as a criticism of progress or lack of progress. The consumption of coal per capita in the country has not increased in the last few years, in spite of the fact that our iron and steel production has gone up 50 per cent in I O yrs., and industrialization in general has very greatly expanded-the production of automobiles, for instance, has multiplied itself nearly ten times; also the standard of living to-day is much higher in all classes than it was I O yrs. ago, and yet the consumption of coal per capita has remained practically on a level. Undoubtedly, therefore, we have made very material progress in the efficiency of our application of coal. 1
By private communication supplementing published reports.
DR. T. E. LAYNG:Mr. Chairman, I would like t o ask Dr. Porter about that 7.I per cent of coal used for gas making, export, and bunkering. The exporting of coal has been severely criticized; a great many people think it ought t o be used in this country. I should like t o know about what percentage of t h a t 7 . 1 per cent is exported. DR. PORTER: My recollection of the figure for export this year is that it is running now over z,ooo,030 tons per month, from tidewater, and a little less exported t o Canada, which will at that rate bring the total for this year close to 40,000,000 or 45,000,ooo tons. The figures in the paper are for 191j . The export figures this year are very much higher than in 1917. The export in 191j , as I remember, was about 23,000,000 toas, or 4.3 per cent of the total coal. Gas making required only about 5,000,000 tons, or I per cent, and bunkering the balance
GASOLINE LOSSES DUE TO INCOMPLETE COMBUSTION IN MOTOR VEHICLES1 By A. C. Fieldner, A. A. Straub and G. W. Jones PITTSBURGH EXPERIMENT STATION, U. S. BURBAUOB MINES, PITTSBURGH, PA.
The rapidly increasing use of motor vehicles in the United States has introduced an entirely new problem in t h e proper ventilation of tunnels, subways, and other confined spaces through which such machines must pass. This problem was brought t o t h e attention of t h e Bureau of Mines last November by t h e New York and New Jersey State Bridge and Tunnel Commissions with reference t o t h e ventilation of the proposed vehicular tunnel under t h e Hudson River. This tunnel, consisting of twin tubes 29 ft. in diameter and S j o o f t . long between entrance and exit (Fig. I ) , presented an unprecedented problem in ventilation both on account of its length and on account of the traffic density, which is expected t o reach a maximum of 1900 vehicles per hour. An exhaustive study b y t h e tunnel engineers of all available d a t a on the amount and composition of automobile exhaust gas disclosed very little information on t h e percentage of carbon monoxide in motor exhaust gas from the average run of automobiles and trucks under actual operating conditions on t h e road. It was well known t h a t carburetor adjustment and other operating factors changed t h e percentage of the poisonous constituent, carbon monoxide, from practically o t o 1 2 or 13 per cent; b u t no safe estimate could be made of t h e most probable figure without further investigation. A series of tests was therefore undertaken in which passenger cars and trucks were tested in exactly the same condition as furnished b y t h e owners from whom they were borrowed. No change WAS made in carburetor adjustment or any other operating condition, the prime object being t o obtain information on existing operating conditions and not t h e ideal conditions of careful adjustment under which t h e usual test of t h e automotive engineer is made. For this reason the d a t a are of especial value in showing t h e proportion of gasoline wasted b y the average automobile owner and truck operator through imperfect combustion. 1 Published with the permission of the Director, U. S. Burealo of Mines and of the Chief Engineer of the N e w York and New Jersey State Bridg and Tunnel Commissions.
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
52
Vol. 13, No.
3
w
..- .. . - . ... - .. .. -
BRIDGE k TUNNEL COMMISS10N 1-0
NEW JERSEY INTERSTATE BRlDGC I TUNNEL COMMISSION
-
HUDSON RIVER VEHICULAR TUNNEL DIAGRAM SHOWING METHOD OF VENTHATION’ PROFILE 6 S E C T W SEC 7/0N OF ONC TUNNEL
PLATE N I C 7
FIG.I-PLAN,
PROPXI.4, A N D SECTIONS OF T H S
METHOD OB CONDUCTING TESTS
All cars were tested in t h e same condition as received, and with the same brand of gasoline t h a t t h e car was using. Fig. 2 shows a 2.5-ton truck equipped with gasoline measuring apparatus (in front of driver’s seat) and exhaust gas sampling tube (back of cab). GASOLINE MEASURING APPARATUS-The gasoline measuring apparatus shown in Fig. 3 was connected directly t o the carburetor and t o a reserve supply of gasoline, v , through t h e copper pipes 12 and c, respectively. As the car crossed the boundary lines of t h e test course a t the predetermined speed for the test, t h e gasoline feed was switched from the reserve supply t o the measuring tube I, by closing t h e cock e and opening q. A t the end of the test course, a reverse operation of these cocks switched the supply back to the reserve supply tank.
4%4kt+@
HUDSONRIYERVEHICULAR TUNNELS
The exhaust gas pressure was sufficient t o maintain a rapid stream of gas through the heavy-walled rubber tube b connected t o the glass tee a on the sampler board. The main stream of exhaust gases passed on through t h e rubber tube b and was discharged i n t o t h e atmosphere through t h e water seal c, t h u s preventing any air from being sucked back into t h e sample. T h e exhaust gas sample was collected continuously a t a uniform rate over t h e whole period of t h e test, in a 250-cc. glass sampling tube connected t o t h e downward branch of t h e tee a. One observer gave his entire attention t o regulating the flow of the water from t h e sample tube, by adjusting the screw clamp at the lower end of t h e tube. A 5 per cent solution of sodium chloride previously saturated with exhaust gas was used.
I
L
FIG.2-23
T’ox TRUCK, LOADSD AND
EQUIPPED FOR
ROADTESTS
S A M P L I N G A N D ANALYSIS O F EXHAUST GASES-The exhaust gas sampling apparatus is shown in Fig. 4. A 0.25-in. copper tube, g, bent a t right angles, with t h e opening turned toward t h e engine, was introduced i n t o t h e exhaust pipe between t h e engine and muffler.
F I G . ~-GASOLINB
MEASURING APPARATUS
The samples were analyzed in duplicate for cos, CO, Hz, N2, and CHI on a laboratory type BurrellOrsat apparatus1 as used in the Bureau of Mines for 0 2 ,
1 G. A. Burrell and F. M. Seibert, ‘‘The Sampling and Examinations of Mine Gases and Natural Gas,” Bulletin 4a (1913),43.
Jan.,
1921
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
Degree Baume BRAND Sp. Gr. A 66.4 0.713 B 0.731 61.5 0.730 61.8 C F1 0.796 45.9 1 Benzene mixture.
Ultimate Analyses HydroFirst Carbon Ken Drop 84.3 i5.7 88 84.3 15.7 93 85.2 14.8 104 88.3 11.7 115
TABLE I-ANALYSES OF GASOLINEUSED -Distillation in 100 c c . Engler Flask, Temp. 10% 127 145 153 180
20% 151 181 187 199
30% 176 214 214 214
complete gas analysis. The carbon dioxide was absorbed in potassium hydroxide solution; t h e oxygen in potassium pyrogallate; t h e carbon monoxide in two bubbling pipets in series, containing acid cuprous chloride solution; and t h e hydrogen, methane, and any residual carbon monoxide were determined by slow combustion in the presence of a hot platinum wire.
40 % 201 239 237 228
50% 225 266 259 248
60% 250 293 282 271
' F.--
70% 282 318 304 309
80% 318 347 327 345
90% 381 394 363 381
53 Distillation
D'y
Po1nt 44 1 45 1 414
430
Av. 239 282 259 264
Loss
Percent 5.0 3.0 3.0 2.0
car was submitted for test. Analyses of these various brands are given in Table I. T E S T COXDITIONS-Tests were made under t h e various conditions which might prevail in the tunnel, a t different times, as for example: Car a t rest with engine idling. Car a t rest with engine racing. Car accelerating from rest t o 15 mi. per hour on level and up a cent grade. Car running 3 mi. per hour on level grade, up 3 per cent grade, 3 per cent grade. Car running 10 mi. per hour on level grade, up 3 per cent grade, 3 per cent grade. Car running 15 mi. per hour on level grade, up 3 per cent grade, 3 per cent grade.
3 per down
down down
The level and 3 per cent grade courses were each one mile long; the surface was asphalt on the grade course, and part asphalt and part macadam on the level course. Trucks and 7-passenger cars were tested with both light load and' full load, t h e light load consisting of two observers, driver, and t h e necessary apparatus. One hundred trucks and passenger cars were tested in the entire investigation; twenty-three were tested under winter conditions, and seventy-seven were tested under spring and summer conditions.
--
RESULT O F TESTS UNDER W I N T E R CONDITIONS
A summary of the results of tests of twenty-three passenger cars and trucks under winter conditions is given in Tables 11, 111, and IV. O F TESTS ON ELEVEN 5-PASSENGBR CARS Com- Lbs. pleteAir Mi. ness of per Lb. Analysis of Exhaust Gas per Corn- Gas& P-er-----cent by Volume-Gal. bustion Tine COz 0 2 CO CHI Ha Nz .. 70 12.2 9 . 1 1 . 5 6 . 9 0 . 8 3 . 0 78 8 69 11.8 8 . 9 1.4 7 . 6 0 6 3.7 77.8
TABLE11-AVERAGE RESULTS
Condition of Test Engine racing Engine idling U o 3 Der cent giade: 15mi.perhr. 10mi.perhr. 3mi.perhr. Down 3 per cent grade: 15mi.perhr. 10mi.perhr. 3mi.perhr. Level grade: 15mi.perhr. 10mi.perhr. 3mi.perhr.
-_
FIG.4-EXHAUST
GASSAMPLING APPARATUS
I n this method of analysis any gasoline vapor and other hydrocarbons appear as methane. I n other words, the analysis gives the equivalent methane value for all t h e hydrocarbons in the exhaust gas, and t h e result is correct as regards carbon content for computing t h e total volume of exhaust gases from the gasoline consumption and t h e carbon content of the gasoline. This relation was checked t o within 6 per cent by actual measurement of exhaust gas in a 50 cu. f t . container. The determination of gasoline vapor as methane causes t h e hydrogen value in the analysis t o be somewhat less t h a n its true value. This error in t h e hydrogen value has no effect on the calculation of t h e true value of CO, COZ, and CHIequivalent of total hydrocarbons. GASOLINE USED-Each car was tested with t h e same brand of gasoline as the driver was using when the
. . . ...
13.2 12.7 6.2
75 75 72
12.6 13.0 12.2
24.5 22.8 9.9
70 70 72
12.3 12.3 12.9
9.5 8.6 9.5
1.4 1.4 1.5
6.5 0 . 9 7.0 0.7 6.00.7
2 . 9 78.8 3 . 1 79.2 2.779.6
16.9 16.9 7.5
76 72 72
1 3 . 4 ' 9.3 9.3 12.7 9.1 12.6
2.2 1.9 1.6
5.6 6.3 6.7
2.8 3.1
TABLEIII-~~vBRAGERESULTS Corn-
Condition of Test Engine racing Engineidling UD 3 Der cent grade: 15 m i . p e r h r . 10mi.perhr. 3mi.nerhr. Down 3 per cent grade: 15 mi. per hr. 10 mi. per hr. 3 mi. per hr. Level grade: 15 mi. per hr. 10 mi. per hr. 3 mi. per hr.
Mi. per Gal.
.... ....
1 0 . 2 1 . 1 5.7 0.6 2.6 79.8 9 . 9 1 . 5 5 . 7 0 . 5 2.6 79.8 9.80.96.50.63.079.2
0.8 0.6 0.6
3.0
79.3 78.8 79.0
OF TESTSON SEVEN 7-PASSENOER C A R S T,hs
pleteAir ness of per Lb. Analysis of Exhaust Gas cent by Volume--Com- Gaso- reP---CO1 Oa CO CHI Hz NJ bustion line 63 12.3 7 . 3 3 . 5 7.8 1 . 4 2 . 9 7 7 . 1 70 13.7 8 . 0 4.3 6 . 3 1 . 2 2 . 0 78.2
7.8 7.8 5.5
68 67 65
12.4 12.5 12.5
8.5 8.2 7.6
1.9 2.0 3.3
7.5 7.5 9.2
0.9 3.3 0.9 3.6 1.2 3.7
77.9 77.8 75.0
16.9 19.4 9.4
61 67 67
14.0 14.9 15.3
6.4 6.9 6.9
6.0 5.0 5.0
6.8 6.2 6.3
1.6 2.4 1 . 2 2.2 1 . 3 2.4
76.8 78.5 78.1
12.3 11.7 6.2
69 69 68
13.5 13.8 13.4
8.2 2.8 6.5 8 . 0 3.1 6.4 8.0 3.1 7 . 0
2.8 2.8 3.0
78.8 78.6 77.9
0.9 1.1 1.0
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
54
150
e
3
l i
l
f
I
Ik \
\.
Fig. j is a graphical presentation of t h e important figures as regards tunnel ventilation, namely, t h e average per cent of carbon monoxide in t h e exhaust gas, t h e gallons of gasoline consumed per hour, and t h e cubic feet of carbon monoxide per hour. TABLEIV-AVERAGE RESULTSOF TESTSO N FIVEL I G H T TRVCKS CornLbs. pleteAir Mi. ness per Lb. Analysis of Exhaust Gas --Per cent b y Volumeper of Com- Gasoline COP 0% CO C H I HZ Nz Gal. bustion 11.3 8 . 3 2 . 0 7 . 7 1 . 2 4 . 0 76.8 , 64 12.0 6 . 6 4 . 2 7 . 1 2.1 3 . 7 7 6 . 3 57
Condition of Test Engine racing Engine idling Vp 3 per cent grade: 1 5 m i . p e r h r . 11.6 10mi.perhr. 10.7 3mi.perhr. 5.9 Down 3 per cent grade: 15mi.perhr.21.6 1 0 m i . p e r h r . 17.1 3 m i . p e r h r . 7.7 Level grade: 1 5 m i . p e r h r . 15.2 1 0 m i . p e r h r . 12.9 3 m i . p e r h r . 6.1
Vol. 13, KO,I
. .. .. ..
73 64 63
12.5 11.0 11.2
9.6 9.0 8.1
1.5 1.3 1.6
7.0 8.5
6.2
0.6 1.3 1.2
3.0 4.1 4.4
79.1 77.3 76.2
63 56 56
12.1 11.7 12.3
7.5 6.5 6.5
3.1 4.1 3.6
7.1 7.7 7.5
1.4 2.2 2.2
3.5 3.6 3.4
77.4 76.1 76.8
67 63 62
11.8 12.0 12.0
9.0 7.7 7.4
1.5 2.1 2.9
7.0 8.0 7.7
1.1 3.4 1.3 3.8 1.3 4.1
78.0 77.1 76.6
D I S C U S S I O N O F RESULTS O F TEsTs-It will be noted from t h e plotted results t h a t the average percentage af carbon monoxide for each class of vehicles varies between 5 per cent as a minimum and 9 per cent as a maximum, the larger percentages tending t o be produced when the engine is racing, idling, or running on Light load on the low gear a t 3 mi. per hr. However, the greatest amount of carbon monoxide per hour is generated under conditions of greatest load, i. e . ,
when accelerating or running up grade a t t h e highest speed. The relative quantity of carbon monoxide produced depends primarily on the gasoline consumption as shown at a glance b y the similar rise and fall of t h e “gasoline” and “cubic feet of carbon monoxide” curves. The average percentage of carbon monoxide under all conditions of test for each class of vehicles was j-passenger cars 6.3; 7-passenger cars 6.8; and light trucks 6 9 , These values are consistently higher t h a n reported by previous investigators. The most extensive road tests heretofore made in this country are those reported by Herbert Chase1 in 1914. A comparison of his results with t h e Bureau of Mines tests is given in Table V. TABLI:\r-cOMPARISON
O F E X H A U S T GAS ANALYSES O F TESTS BY A N D B Y THE BUREAUOR MINES
CHASE
Average Exhaust Gas Analyses -Per cent b y Volume -Carbon Monoxide- -Carbon DioxideChase B of M Diff Chase B. of M. Diff 0.3 7.1 8 . 4 8 .1 4.5 Cars standing engine idling 2 . 6 Cars accelerathg t o 10 mi.’ 0.6 5.6 9.5 1.9 3 . 7 10.1 per hr. from rest.. . . . . Cars running 10 mi. per hr. 0.9 8.8 9.7 6.7 2.3 4.4 on level grade.. . ... , . Cars running 15 mi. per hr. 0.5 9.0 9.5 6.3 2.5 3.8 on level grade.. AVERAGE .. 2.3 6.4 4.1 9.4 8.8 0.6 1 15 mi per hour in Bureau of ?Mines tests
. . . . .. . . . . . . . . ... ....... . ....
~____-
1 “Exhaust Gas Analysis for Economy,” The Automobile, 30 (February 1914).
T H E J O U R N A L OF I N D U S T R I A L A N D E N G l N E E R I N G C N E M I S T R Y
Jaa., 1921
T h e average of all comparable tests shows 0.6 per cent more carbon dioxide and 4.1 per cent less carbon monoxide in the Chase tests t h a n in the Bureau of Mines tests. The cause for t h e large difference in carbon monoxide percentages is not clear, in view of the agreement in t h e carbon dioxide results. If t h e carburation and combustion of t h e less volatile present-day gasoline is less efficient t h a n in 1914 we should expect a corresponding difference in t h e carbon dioxide percentages. Hood, Kudlich and Burrel1,l have shown t h a t t h e proportion of carbon monoxide in exhaust gases varies from o t o about 14 per cent, t h e amount depending on a number of variables, chief of which are: (1) (2) (3) (4)
Ratio of air t o gasoline Completeness of vaporization and mixing Speed of engines Temperature of air and jacket water ( 5 ) Quality and time of spark (6) Degree of compression (7) Quality of gasoline or motor fuel
POOREST RESULTSOBTAINED O N S E V E R A L REPRE. MAKES OF PASSENGER CARS A N D TRUCKS (All cars loaded)
.a
1 c 9 c 11 G 10 G 84 X 76 X 38 Y 57 Y 44 D
5-passenger 5-passenger 7-passenger 7-passenger (/et. truck 8 / 4 4 . truck 3.54. truck 3.54. truck 5-passenger
15 15 15 15 15 15
I
27.30 105.8 100 13.26 84 18.61 66.8 93 11.16 . . . . . 61 15.39 4 4 . 5 90 10.66 . . . _ . 59 10 6.55 36.2 87 65 10 4.81 49 15 10.26
.....
.....
.....
.”0
16.7 13.5 20.1
10.7 16.6 10.3 13.9 10.2 9.0
Table V I gives a comparison of the best and poorest t.ests obtained on several well-known makes of passenger ~ ~ ’ G a s Mine ~ l i ~~ o ~ c o m o t ~in v e~s Bureau of Mines, Bulletin 74 (1915)
CARBURETOR ADJUSTMENT O N GASOLINSCONEXHAUST GAS ANALYSIS 4-cylinder roadster engine 41,’s in. bore X 4l/z in. stroke: Johnson carburetor; intake air knd manifold ?heated; using gasoline 66.4’ BaumC distillation l o % , 127’ F ‘ 50%, 225 F., dry, 441 F.; average 239’ F: Tests a t 15 mi. per hr. aiiending a 3 per cent grade of asphalt in good condition. OF
SUMPTION AND
AND
SENTATIVE
and greatest mileage of any car tested. Car KO, 44, cars and trucks. Cap Mo. 1 had the best gas analysis, also a 5-passenger car, had t h e poorest gas analysis and t h e lowest mileage in its class. Both cars operated without any apparent difficulty throughout the tests. Car No. 1 1 did not operate smoothly and lacked flexibility at low speed due t o t h e mixture being too lean. However, t h e mileage per gallon of gasoline was much higher t h a n t h e other cars in t h e same class. At speeds above 1 5 mi. per hr. i t operated smoothly and gave a good illustration of t h e tremendous quantity of fuel t h a t may be saved by using lean mixtures. It should be noted t h a t in each case t h e car with t h e leaner mixture shows the largest mileage per gallon of gasoline. The percentage increase in mileage ranges from 36 t o 106 per cent. The effect of various carburetor adjustments on an individual car is shown in Table VII. TABLEVII-EFFECT
I n view of this large number of variables i t is not surprising t h a t extremely large variations in exhaust gas composition were obtained in testing motor vehicles taken from ordinary service without any adjustment prior t o test and driven in a variable manner with foot accelerator or hand throttle by different drivers over an approximately smooth course, but yet one with some rough places requiring opening and closing the throttle t o maintain a constant speed. It is, therefore, not possible t o draw conclusions on t h e effect on exhaust gas composition of t h e various factors just enumerated, except with regard t o t h e first one, namely, “ratio of air t o gasoline,” or carburetor adjust mer1t. EFFECT OF C A R B U R E T O R ADJUSTMENT-A study of all t h e tests shows t h a t t h e variation in exhaust gas composition due t o carburetor adjustment is far greater t h a n any other factor; they do not throw much light on t h e advantage of any particular make or type of carburetor, nor should any conclusions be drawn as t o t h e merits or demerits of any particular make of car. T A B L EVI-BEST
5.5
~ to Safety l and~ Health,t# ~
2; P .-Sa &+
52
Gasoline -Consumption-Gal. Miles Exhaust Gas o per -Analyses, per Per cent---2Z 0 Mile Gal. COz 02 CO CH4 Hz Nz cl $ 1 0.067 14.9 n 13.4 1 . 7 1 . 2 0 . 2 0.0 83.5 14.5 95 13.9 b ll/d 0.072 12.0 1.4 2 . 0 1 . 1 0 . 0 83.5 14.2 85 10.6 10.2 0 . 3 6 . 4 0 . 8 2 . 4 7 9 . 9 11.8 74 c 17/10 0.094 8.8 9 . 9 56 d 18/4 0.1142 6.51.211.61.06.473.3 a-Exhaust clear, mixture too lean t o operate without use of air choke. &Exhaust clear, operation satisfactory. Air choke 1/4 on during p a r t of test. c-Exhaust slightly smoky; operation satisfactory. Car had good “pick-up.’’ d-Smoky exhaust; mixture seemed too rich for satisfactory operalion. $ 0
D
22
-
2
Before putting this car through the standard series of road tests t h e driver, an automobile mechanic, was asked t o place t h e carburetor in good adjustment. He set i t after t h e engine was warmed up t o running conditions, a t I’/,~ turns of t h e needle valve. As shown in t h e table this setting produced 6.4 per cent carbon monoxide and 10.2 per cent carbon dioxide, a little better t h a n the average analysis of all t h e cars tested. Tests were then repeated under identical conditions with both richer and leaner settings. It was found t h a t 1>/4 turns of t h e carburetor needle gave 1 2 per cent COz and 2.0 per cent CO; and 3 1 per cent greater mileage; also t h e car operated satisfactorily. This test is typical of t h e great majority of t h e passenger cars and trucks tested, they were invariably adjusted safely on t h e rich side for greatest flexibility of operation rather t h a n for maximum economy of gasoline. R E A S O N S F O R E X I S T I N G U S E O F RICH M I X T U R E S
One pound of ordinary motor gasoline of to-day, such as~ Was ~used in t h e tests just described, requires i approximately 1 5 Ibs. of air for complete combustion.
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
56
AVERAGECOMPOSITION OF EXHAUST GAS, BY VOLUME, CARSAT 15 MI. PER HR.
18
a: e 15 28
Level Grade Per cent Carbon dioxide.. . . . . . . . . . . . . . . . . . . 8 . 9 Oxygen . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 Carbon monoxide.. . . . . . . . . . . . . . . . 6 . 3 Methane . . . . . . . . . . . . . . . . . . . . . . . . . 0.9 Hydrogen . . . . . . . . . . . . . . . . . . . . . . . . 3.0 Nitrogen.. . . . . . . . . . . . . . . . . . . . . . . . 78.6
?h PP/3
TOTAL ......................... 100.0 Cu. f t . exhaust gases a t 65‘ F. and
17 h
$,$/6
bQ
--
9 ?I4
29.92 in. Hg ....................
QL
gg/z 10
EXHAUST GASFROM
TESTS OF 23
Ascending 3 Per cent Grade Per cent 9.6 1.3 6.4 0.6 2.9 79.2
--
100.0
988
1 GAL. GASOLINEON LEVELGRADETESTS CGNTAINS
988 X 6.3 = 62.2 cu. f t . CO 988 X 0.9 = 9.1 cu. f t . CH4 988 X 3.0 2.9 CU. ft. Hz
e89 %3
TOTALHEAT IN UNBURNED GASES PER GALLONG A S O L ~ N E B. t. u. 62.2 X 320’ = 19,900 9.1 X 1000 = 9,100 29.6 X 322 = 9.500
7 6.?0 19
FROM
Xo. I
COMPOSITION OF GASOLINE Sp. Gr . . . . . . . . . . . . . . 0.713 Carbon. . . . . . . . . . . . . 8 4 . 3 per cent Hydrogen. . . . . . . . . . . 1 5 . 7 per cent Calorific value.. , . , , , 21,300 B. t. u. per lb. = 130,000 B. t. u. per gallon
?$// 9s
$;
Vol. 1 3 ,
I7 /6 15 /4 /3 /2 // / O 9 RATIO OF AIR TO GASOL/N&, POUNDS
f8
6
7
6-cURVES S H O W I N G RELATION BETWEEN BRAKEHORSEP O W E R A N D THERMALS:I.FICIENCY AT VARIOUS AIR-GASOLINE RATIOS. AFTER BERRY
__
1
FIG.
The maximum thermal efficiency is obtained a t about 16 lbs.1 of air t o I lb. of gasoline, and the maximum power with 1 2 t o 1 3 Ibs. of air.2 Herein lies the reason for the use of rich mixtures. The average driver demands first of all power and flexibility of operation. He sets his carburetor adjustment rich enough t o give good operation with a cold engine and for slow driving in heavy traffic, with plenty of reserve power for hill climbing and bad road. If he errs somewhat on t h e rich side i t does not become manifest in loss of power, but only in t h e increased gasoline consumption, which in many instances does not concern him a t all. An inspection of t h e average thermal efficiency and power curves of Fig. 6 shows t h a t the proportion of air in the mixture can be reduced t o 9.0 lbs. of air t o I lb. of gasoline with a loss of only 9 per cent in power, although economy and efficiency are tremendously reduced. Fig. 7 shows t h e relation between the air-gasoline rates and the percentage of carbon monoxide in the exhaust gas for t h e first 23 passenger cars and trucks tested a t I j mi. per hr. running up a 3 per cent grade. The air ratios varied from 1 5 . 8 with about 1.0 per cent carbon monoxide, t o 9.7 lbs. air with 12.3 per cent carbon monoxide. The average air-gasoline ratio was 12.4,with a n average carbon monoxide per cent of 6.3, practically t h e exact figure for maximum power. Obviously, carburetors are adjusted in practice for maximum power and not for maximum thermal efficiency and economy of gasoline. The average loss of gasoline due t o t h e continuous operation of a car at t h e point of maximum power is shown in the accompanying computations from average exhaust gas analyses, heat in t h e gasoline, and heat in t h e unburned exhaust gas constituents. 1 With this mixture t h e engine develops about 85 per cent of its m a x imum power. 4 0. C. Berry, “Mixture Requirements of Automobile EnRines,” J . SOC.Aatomotfve‘ Eag , 6 (1919), 364.
38,500 Gross B. t. u. per cu. f t . a t 65’ F. a n d 29.92 in. Hg. 38’500 = 13o.000
29.6 per cent
29.6 per cent of t h e total heat of the gasoline goes o u t in the exhaust in the form of combustible gases.
7-cuRVE S H O W I N G RELATIONBETWEEN AIR-GASOLINERATIO AND CARBONMONOXIDE I N E X H A U S T GAS OF 23 CARS T E S T ~ D AT 15 MILES PER HOUR RUNNINQ UP A 3 PER CRNT GRADS
FIG.
RESULTS O F TESTS UNDER
SPRING A N D S U M M E R
CONDITIONS
While t h e d a t a just given for winter conditions show surprisingly large losses due t o incomplete combustion, incomplete returns on t h e summer tests show even larger losses. As shown in Table V I I I , passenger cars and t h e lighter trucks average from 6.0 per cent t o 7 . 6 per cent carbon monoxide. TABLEVIII-COMPARISON
OF
PERCGNTAGE
OF
CARBON MONOXIDEI N
EXHAUST GAS IN WINTER AND SUMMBR
Average Per cent Carbon TYPEO F CAR -Monoxide in Exhaust Gas’Winter Summer 7.6 5-passenger c a r . ..................... 6.3 7.4 6.8 ?-passenger c a r . ..................... 7.7 Trucks up t o 1.5 tons. 6.9 6.9 Trucks 1.5 t o 3 t o n s . , . . . . . . . . . . . . . . . . . . 6.3 Trucks 3.5 t o 4.5 tons. ,.. Trucks 5 tons and o v e r . . 6.0 1 Average of all conditions of test previously described.
............... ............... ............ ...
Jan., 1921
THE J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
It appears t h a t most cars are adjusted t o start easily i n cold weather and then are permitted t o remain t h e same during t h e entire summer, thus increasing t h e wastage of gasoline during the period of greatest consumption. Probably jo t o 7 5 per cent of t h e present daily loss o f gasoline due t o t h e prevalent use of rich mixtures could be prevented by proper adjustment of existing forms of carburetors. Unfortunately, most drivers not care t o change even a simple manually controlled adjustment from t h e dash. They set i t rich enough f,ox the heaviest load and then leave i t the same for all duties. AUTOMATIC CARBURETOR NECESSARY
It is hoped t h a t t h e results of these 23 tests and t h e remaining 7 8 which will be published a t an early d a t e will serve as a stimulus t o automotive engineers t o ‘design an automatic carburetor as suggested b y W. E. Lay,’ who states: The ideal carburetor would be arranged so as t o supply primarily the mixture giving the best efficiency a n d automatically supply the necessary additional fuel only when operating Conditions require it. The provisions made should be 50 adequate t h a t the economy under proper operating conditions will never be sacrificed t o obtain more power or better operation under exceptional conditions. SUMMARY
Road tests under winter conditions for the purpose of determining t h e amount and composition of motor exhaust gas from automobiles a n d trucks of various sizes when operated on grades and a t speeds similar t o those t h a t will prevail in vehicular tunnels have shown t h a t : ( I ) The exhaust gas composition of individual machines varies greatly, and the controlling factor is t h e ais-gasoline ratio produced by the carburetor adjustment. (2) The percentage of carbon monoxide for the majority of cars lies between j and 9 per cent. (3) The average percentage of carbon monoxide for 23 cars tested was 6.7 per cent, which is practically the ratio for developing maximum power. (4) The combustible gas in t h e average automobile exhaust from one gallon of gasoline amounts t o 30 per cent of the total heat in a gallon of gasoline. (5) The great majority of motor cars and trucks are operated on rich mixtures suitable for maximum power but very wasteful from the standpoint of gasoline econoniy. ( 6 ) On t h e average, carburetors are set in the winter and not changed in the summer, as shown by t h e higher percentages of carbon monoxide found in the summer test. ( 7 ) A simple and convenient dash adjustment for instantly throwing a carburetor adjustment from t h e condition of maximum thermal efficiency t o maximum power for steep hills and for starting t h e machine would probably result in saving 2 0 t o 30 per cent of 1
189,
“Saving Fuel with the Carburetor.” J . SOC.Automotiue Eng., 7 (1920),
57
the gasoline used, not a small item when we consider the total gasoline used by the 7,500,ooo automobiles and trucks operating in 1919. (8) An automatic self-changing carburetor which gives rich mixtures for power only when needed would be t h e solution of t h e problem of saving gasoline losses from incomplete combustion. DISCUSSION
GEORGEG. BROWN:Mr. Chairman, I have been very much interested in this proposition of combustion gas in the carburetor. Back in 1913, the time so many analyses were made, the truck drivers were more careless with their carburetors than they are now, although we found t h a t some of them did fairly well day after day under the same truck driver. One reason for this change is that the carburetors have been improved. But here are a few facts which may be interesting and which have been checked by the Royal Automobile Club of England. They have found the maximum power for a car runs about 1 2 parts by weight of air t o I part of gasoline. That would give an excess of gasoline, and therefore some carbon monoxide. The maximum thermal efficiency runs about 17 parts of air by weight t o I part of gasoline. That is a n excess of air; and for complete combustion, depending on the kind of gasoline used, it runs about 14.5 t o 15 parts of air. As has been pointed out, the key to the whole situation is really in the design of a carburetor. A properly designed carburetor should give I z parts of air to I part of gasoline when climbing a hill, and when running on a level i t should automatically give 1 7 parts of air t o I part of gasoline. I n other words, what is wanted is the uniform mixture for maximum economy; we want what most carburetors do not give, a light mixture when the engine is running light, when running a t high speeds, and a heavy mixture when the engine is running slow on heavy load. Most of the carburetors on the market a t the present time have just the reverse action, because a t a higher velocity all of the air going through the carburetor causes a greater proportion of gasoline t o be drawn into the mixture than is the fact under reverse conditions, so that in going at higher speeds we get a richer mixture. At the point where you get the richest gas you want the weakest. We have been working on this, and we have got thus far: We can get a light mixture when the engine is running light and a heavy mixture when i t is running heavy. If we can get a carburetor on a car so that it will answer automatically and scientifically all changes in road conditions and all changes in temperature, and if we can then locate the carburetor so that the driver cannot adjust it except with the aid of a service man, I think we have gone a long way toward getting the maximum efficiency out of the engine. We have got everything lined up except the temperature, and we can work that out very shortly. I a m not prepared t o go into the theory of the whole proposition with you, but I thought I would bring this out a t this timenot only the adjustment of the carburetor, but what you want is a scientific, fool-proof carburetor, and there is nothing of that kind that I know of in the market a t the present time, MR. R. E. WILSON:I would like t o ask if the amount of carbon monoxide is going t o make the ventilation in that tunnel a particularly difficult matter? MR. FIELDNER: No, it doesn’t make it particularly difficult, but it will take some power and machinery t o do it. The engineering difficulties are not so great as one might think. They have t o put through about 1,500,ooo cu. f t . of air per minute. In reference t o Mr. Brown’s remarks on carburetors, it is interesting t o point out that the average of the air-gasoline ratio on the I O cars tested by the Bureau of Mines was something like
T H E J O U R N A L O F I N D U S T R I A L A N D ENGIhTEERING C H E M I S T R Y
58
1 2 . 5 ; in other words, carburetors are adjusted for maximum power rather than maximum thermal efficiency. MR. BROWN:We figured out a few years ago that running on a theoretically perfect combustion basis, that is, about I j parts of air t o I of gasoline, the mileage of a Ford would be a little over 26 mi. per gal.; if you are getting 20 mi. per gal. on a Ford you are getting what should be obtained without a n y excess gasoline, without any carbon monoxide in your exhaust. We have obtained as high as 38 mi. per gal. with careful adjustment and careful driving, but over a long period of driving through streets, etc., we have averaged over 28 mi. per gal. On the basis of getting a very light mixture, we can get 26 mi. t o a gallon on a Ford. Usually a man makes 2 2 or 2 3 . A man in Long Island told me the best he knew was 19.5. There is a tremendous saving t o be made there, aside from the fact that we are relieving the engine from pumping through I,OOO,OOO cu. f t . of air in a minute, because we have found an average of less than I per cent carbon monoxide under all conditions.
ENRICHMENT OF ARTIFICIAL GAS WITH NATURAL GAS By James B. Garner RSSEARCH AND DEVELOPMENT DEPARTMENT, H O P E PEOP~E NATIONAL S GAS COMPANIES, PITTSBURGH, PA
DIRECTOR OR
AND
ABSTRACT
The project of enriching artificial gas with natural gas is of widespread interest because of t h e possibility i t offers of providing a supply of a clean domestic fuel gas, uniform in quality, and of sufficient volume t o meet t h e requirements of t h e public. This is particularly t h e case in regions where natural gas has been used. There are in nature three potential sources of raw materials adequate for t h e production of a future domestic supply of manufactured gas: bituminous shale, oil, and coal. Artificial gas, as produced on a commercial scale, consists of t h e following varieties: shale gas, oil gas, producer gas, water gas, carbureted water gas, coal, and coke-oven gas. Shale gas has been made arid utilized with some degree of efficiency in Scotland, and considerable experimental work has been done in t h e United States looking toward t h e development and utilization of our vast beds of bituminous shale. With our present lack of engineering and technical knowledge regarding t h e use of bituminous shale as t h e future source of an adequate supply of manufactured gas, its geographic location and availability is such t h a t bituminous shale cannot now be considered as a n immediately available raw material. Oil gas is t h e domestic gas of San Francisco, Oakland, Los Angeles, Portland, Tacoma, and San Diego. Oil is used as t h e basis of gas manufacture in these western cities because of t h e nonavailability of cheap coal, while cheap oil is available. In all other sections of t h e United States, gas-oil or other products from petroleum are so expensive t h a t t h e manufacture of oil gas is economically prohibited. Producer gas, water gas, carbureted water gas, coal: and coke-oven gas have all been made and used with greater or less success for many years past. Coal seems t o be-the only raw material which is a t
Vol. 13, No.
I
present available as a basis for a future gas supply. Producer gas is unsuited for use as a domestic gas for two reasons: ( I ) Its high content of inert nitrogen, and cost of cleaning, cooling, and distributing.
(2)
the excessive
Coke-oven and coal gas of a high quality are made, but on account of the cost of installation and nonflexibility of t h e plants wherein these gases are produced, these processes of manufacture are unfitted for use in meeting t h e peak-load requirements of an adequate domestic supply. Blue water gas, although lower in heating value t h a n coke-oven or coal gas, can be made most economically; and in a plant which is cheap in its cost of installation and flexible in its operation, blue water gas is a t present t h e only rational basis for an adequate supply of clean, uniform fuel gas t o meet peak-load public requiltements. Blue water gas carbureted by means of gas oil cannot, under present market conditions of crude petroleum, be t h e kind of commercial gas for an adequate public supply. I n addition, this use of the waning supply of crude petroleum is far from t h e conservation of one of our greatest natural resources. I n order t o carburet water gas of an initial heating value of 32j B. t. u. per cu. f t . so t h a t i t will have a heating value of 570 B. t. u. per cu. ft., i t is necessary t o use 3 gal. of gas oil per 1000 cu. f t . of gas. The present market on gas oil is 1 2 cents per gallon. The enriching of 1000 cu. f t . of gas thus costs t h e producer 36 cents without any overhead, production, or depreciation charges. Natural gas, as produced in t h e Appalachian and Mid-Continent fields, has an average heating value of 1100 B. t. u. per cu. ft. It can readily be seen t h a t less t h a n 80 cu. ft. of natural gas has an enriching value equal t o one gallon of gas oil. Natural gas can be mixed with blue water gas easily, safely, and without any overhead, production, and depreciation charges, a n d is, therefore, t h e ideal enricher of water gas, in regions where natural gas is available. The manufacture of a domestic supply of water gas, enriched with natural gas, serves two purposes: ( I ) It conserves in the highest pohible manner our iiatiir.al resource3 of coal, oil, and gas. ( 2 ) It insures t o the public an adequate supply a t all times o f a clean, uniform gas at the lowest possible cost.
Natural gas companies should no longer sell. natural gas as such at ridiculously low rates, b u t should utilize i t in the highest possible way, viz., as a means of e n riching artificial gas. Such use of this natural resource will insure t o t h e public, for many years t o come, a supply of gas a t a cost otherwise impossible.
THE CHARCOAL METHOD OF GASOLINE RECOVERY By G. A. Burrell, G. G. Oberfell and C. L. Voress
Inasmuch as this paper has already been published in another journal i t is not included among the s y m posium papers here.
