Performance of an industrial engine as affected by various fuels and intake manifolds

Item Type text; Thesis-Reproduction (electronic)

Authors Thomson, Quentin Robert, 1918-

Publisher The University of Arizona.

Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.

Download date 03/10/2021 00:43:46

Link to Item http://hdl.handle.net/10150/319623 PERFORMANCE OP AN INDUSTRIAL ENGINE AS AFFECTED BY VARIOUS FUELS AND INTAKE MANIFOLDS

by Quentin R. Thomson

A T h e s is submitted to the faculty of the Department of Mechanical Engineering in partial fulfillm ent of the requirements for the degree of MASTER OF SCIENCE in the Graduate College, University of Arizona

1953 Umv, of Arizona Library This thesis has "been submitted in partial fulfillm ent of requirements for an advanced, degree at the University of

Arizona and is deposited in the hihrary to be made avail­ able to "borrowers under rules of the Libraryo Brief quo- tations from this thesis are allowable without special permissions, provided that accurate acknowledgment of source is made 0 Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may "be granted "by the head of the major department or the &ean of the Graduate College when in their judgment the proposed use of the m aterial is in the interests of scholarship® In all other instances 9 howeverj permission must "be obtained from the author 0

SIGHEBg TABLE OF COBTEBTS

CHAPTER PAGE

_ . iETROBBOTIOR » , 0 V ;> » o o B 0 O 0 0 ,• 0 .' "'1

H e EESCRIPTldS p TEST • IHSTALLATIOB 0 a , 0 o' 0 • : 4 IP I &:' , TEST PROCEDHBE . . 0 * » & 0 0 0 ’ . 9

, Types of Tests > = e 0 0 t. 0 0 0 © n © ' 9 • Stabilizing Engine Conditions 0 0 1 0 e 0 d 9

Fuel IlixtuS’e C ontiol: « ^ ;0 ■ 0 . 0 0 0 * .<© -' r 0 10

;tv lgniti.dn Timing <= <, .» =$ 0 >: <. 0 © * © ‘ '■ 0 ■ 11 .

D eseription of Test Runs e • ;s =. 0 0 © J 0 0 11

IV. FUELS AZD FUEL COSTS . 0 > 0 « ^ 0 ©' © 0 : 1 4

■-Oasolxne 0 0 0 0 ® 0 0 » & 0 * 0 . -.. ©: 0 0 . ' 14

G a s o lin e C o sts = 'V® ® ®; » 8 <, e 0 " ■*- * © -- ° ; 14

- '^Cenosene ©■.’ 0. ® 0 & ,0 -0 . ® & 0 ■.ft- 0 e 0 14 -

■ Kerosene Costs : o «, « -•o' ' , 6 : > 0 0 0 ^,T §

Li gu ef i ed®Pet rdl etim Gas . ® 6 0 ’ .0 -■ 9 0 0 .■' ■L5 -;

Liqiiefied^Petroleum Gas Costs O O 0 0 - 0 0 1 7 .

H atural Gas . #/»•. ».'» ■ ®0 *. » 6 O 0 0 © © 0 17

natural Gas Costs « » „ 0 6 0 0 . 0 0 18

, : :,V0; :; IHTAKi: MABIFOLDS » » . » . . = .»■0 0 © 0 0 0 .1 9

The Gasoline Manifold L. 6 . 0 0 0 / 0 0 '..19,''

The Comhination Manifold- 0 » 0 0 0 0 e ©

:' ; '.':The ’ Gay' M anif old . = . 0 0 0 0 0 0 25 '

The Updraft Rahe Manifold , 0 <,■ 0 e 0 0 0 0

\ Vi a ■ DISCUSSIOH OF PERFOMSnCE DATA 0 0 0 0 0 a 28 . GHAPm; - / -y: .■,■■ ■.••'. v. m #m

, V II, : ;COK?LUSIOES , , o e o , , o , , o , -"o , o , 57

' iB XlBItlOCTJiAiPirY' G ; O

. 2 o ::■: PHOTOGRAPH - CASE GAS OL IKE MAHIFOLD , o ■.. »0 W

3 o PHOTOGRAPH - CASE C OMBIHATIOE MAHIPOLB 0 „ 0 22

4» PHOTOGRAPH - GAT MAHIEOEB 0 o . » » . . 24:

' § 0 -": PHOTOGRAPH - RAKE MAFIPOED = o . «, » . > . 25

6 .o GRAPH - BRAKE HORSEPOWER VS. SPEED FOR POUR DIPEEREHT PGEL8 WITH' THROTTDE SET .' ' WTDE OPEH o o o o o o o o o © © o © © -@ © 2 9 : 7 © GRAPH - SPECIFIC FUEL COHSUEPTJOK VS © : ’ SPIED POE THREE -Dl'PHSREHT PUEES WITH " : THROTTDE 'SET WIDE OPEH' © : = A © . © = « © =. © 31

8 © ‘ GRAPH - BRAKE HORSEPOWER VS© SPEED POR,: ' ' POUR DIPPEREHT FUELS WITH THROTTLE SET AT 70 PER CEZT LOAD :; - © /;0 . ©. ;0 © . © c 33 9© GRAPH- - SPECIFIC FUEL COHSUEPTIOH VS© SPEED, FOR THREE DIPPEREHT FUELS WITH ..THROTTLE; SET;-AT 70 PER CEHT LOAD = © © y , A "© 54

' 10 © GRAPH ~ SPECIFIC FUEL COHSUHPTIOE VS© ^ BRAKE -HbRSEPQWER. FOR THREE DIFFEREHT FUELS. AT COSTS TAUT SPEED OP 1550 RPM © © © 35 ’I'la GRAPH “ ■ SPECIPIC FUEL COHSUMPTIOH VS© . .BRAKE HORSEPOWER' FOR TWO DIFPEREHT FUELS . AT COHSW 1700 RPM © © .- o ; © 37 ' 12..o ' GRAPH - BRAKE HORSEPOWER VS © SPEED FOR ' FOUR- D1FESREHT IHTAKE MAHIFOLDS USIHG - : ' ‘ GAS OL IRE FUEL WITH THROTTLE SET WIDE OPEH © ■ '58..- 13© GRAPH. - SPECIFIC FUEL/COHSTOlPTIOH VS.„ ' .. ' . SPEED FOR FOUR DlPFSREHT IHTAEE MAEIFOLDS V : ■ " GAS OL IRE FUEL USED WITH THROTTLE SET ' - A W im : OPEH ■ © ©. ©. © o- © © © © © ©, A & © © © 40; v

' - MfflBBR ' : ; v'-.' , ^ ; :. PAG® " v: A4'd:, .GRAPH— BBAEE HGRSBPOV/ER VS. SPEED FOR V :;:': THREE P1FEBEENT IHTAKS MAHIFOLDS US 1HG . ' :; : • GASORIEE ^ EUER WITH THROTTEE: SET; AT :' . ' . 7 0 PER-.GEHT EGAD *A. ... ■» V- . A; * . -

' 15 o GRAPH - SPEGIPIG IUEE GOHSOT3PT.IOH VSo: ^ : .v SPEED EGR THREDE P IP m R m T . IHTAEE •; ; ; RAHIFOLDS USIHG C-ASOLIHE EGEE WITH 7 V ; - ;;■■■• : - THROm E SEP AT 70 PER GIRT EOAB'A. ' = ::.-=: . <= : 43 - v 16® GRAPH> SPEGIPIG MEL GOHSDMPTIOH VSo BRAIE HGRSEPOWER FOR' W O . RIPEBRES'T IHTA1E' • ' : V ■ MAHIFOLBS AT GOHSTAHT SPEED OF 1550 RPH V .. 45 i ? o GRAPH; - ■ BRAKE’ HORSEPOWER VS. SPEER FOR ; " i " ; -:' = TWO BIFEEREHT' IHTAEE' mHlFOERS H81HG . • . . • • : HATURAE' GAS ' FtJEG WITH THROTTLE SET WIDE. ; : v . ‘ OPEH O' O- © OO O C O .0 o o O' 6 6 O ' 0 ' 8 - O' 0 .. - 46 - '18© P - HPEGIFIG: FHEL: GORSHIIPTIOH FS „ ' ; P- ’ SPEER- FOR HATURAE GAS FUEL- USIHG TWO : -XV--p , ..;/ .1 P BtFFEEEIili. THm ©" » o 6„ ;> ' © 48 ■' : ■ 19 © GRAPH - :i:SPEGlFlG -'FI3iai;'.eoH^ P ■' ■ :' . .. - ^ EAHIFOLPS " . - HSIRG HATURAE,. GAS FUEL WITH THROTTLE . . ' ' -: SET .WIRE^aPER; Go, .^o/ , ot' o \. . . « o . 49

20© GRAPH. " SPSGIFlO FOER., dOHStmPTlOS VSo BRAIE HORSEPOWER FOR TWO.. RIFFEREHT 1RTA1E • 7 7 MA1TIF01DS US IMG HATURAI GAS FUEL AT . P ' ' 7 " - ROHSTMT ,SPEER o » , , 7 © © , © = o/.o'-* o - 51 : ' R io GRAPH- » IHTAKE HAHIFORB TEMPERATURE VSC ' ' . - .SPEER FOR THREE RIFFEREET IHTAEE - . . ■ - ' : HAHIFOLDS USIHG GASORIME FUEL WITH THROTTLE . ' , ' SET WIRE OPEM ; © © « o © © WVP© 0 o. s 52 /

' • 22© , GRAPH = SPEGIFIG FUEL GOST VS © SPEER FOR ^ FOUR RIFIEREHT FUELS o; V ©. © o 0 - o . 0 .© 0 .53 : " 23 © GRAPH " SPSCIFIG;: FUEL GOST VS/BRATfR . ■■ ' HORSEPOmR FOR FOUR RIFFEEHEFT FUELS ' . - ; • . WITH GOHS.TAZT. SPEER APR VAR1ABRE ROAR o © : 55 P - eH&pfBR i :

IHTRODUGTI.OH

■ Sie experimental work performed in preparation for this thesis was done in -an effort "to determine the effeets

of:ffsriods fuels and intake manifolds on the power output

and fuel economy of a spark ignition 9 industrial type 9

internal combustion engine 0 -■ ; , Owners of industrial engines are. faced with the prob- lem-of .'Selecting them ost advantagedus ‘ fuel-, for . th eir

en g in e 0 . Closely allied with this perplexing situation is

the selection of a proper intake manifold for each fuelo

The experimental work ;^id research for this thesis was directed toward an - Invest igation and-analysis of these

problems. ' - ' ■ , . : : . r;' ; ; -v- J’our. fuels .-(gasoline,.-; kerosene.®:: liquefied=petroleum gas j and ‘natural gas} .-were tested using a Case- Model SB

industrial'engine attached to an electric dynamometer installationo Data, were taken: under conditions of f u l l ,

load and part, load with yariable speed: and under the condi tions of constant speed and variable loadc, The engine was

adjusted for each fuel in order to secure maximum perform­

ance consistent with good economy of operation o - .-

Four different intake manifolds were subjected to - experimental tests oh the Case engineo Performance data were taken _tmder conditions . of variable load and speed as

was done for the various fuelso For the intake manifold tests additional test information was obtained in that individual cylinder pressures and air^fuel ratios were measuredo This was done so that an analysis of the power and fuel distribution among the cylinders could be made a

The Case gasoline manifold 9 supplied as standard equip­

ment for use with gasoline fuelp was used as the■primary reference manifoldo The second manifold tested was the Case combination manifold supplied’by the manufacturer to owners desiring to utilize-either kerosene or gasoline' for .fuel-b The- third manifold tested was-one designed by-Say^.

for use on the Case engine in conjunction with a-Ford 6 © . carburetoro In order to continue the investigations made by Cay and Maynard on a rake type-manifold a fourth mani­ fold was, ■designed and fabricatedo This new manifold was designed to test and compare an updraft rake type manifold

with manifolds: supplied by the manufacturero -In order to make an accurate comparison between these manifolds the

new manifold was designed to match the standard equipment

, Ted Gayp "The Effects of Manifold”: Design Changes on Charge distribution and Engine Performance$,M (unpublished M asters Thesis, University of Arizona, Tucson 9 195©) o

'Samuel So Maynard 9 "Power Distribution of a Gasoline' ' ' Engine s..1’ funpublished M aster ''s thesis s U niversity of Arizona % Tucson, 1951)o: : " earburetoTo The new design manifold was designated the- ^ ^'rake :manlfelde' : ; : ■ V v, ; The intake man if olds were tested and compared with:.

. respect te power output 9 specific fuel eonsumption 9 and

power and fuel distribution to the individual cylinders © " , mscRiPTiom os’ fEBT ma? 4 iM T ic ® •

The test inst& llation eonsisted of a Model 16SB” Gas® '

engine 'Bni t direet=conneeted ' to- a General E leetrie Company ■' ;

oradle=moun t ed else trie dgmamometer (Figure 1) 0 • & e -' eBglne; :tm;ed -msf a todi- v e^Etndef 9. four-stroke r

eyeleg overhead - valves, spark lgnitl; 0 @.a. internal combustion :engineo it was a standard model Gase engine less the follow­

in g equipm en ts a i r © le a n e r g - s a t er„ -pump 9; -r ad ia t qry; fan -9 - ; - v '

starterg generater 9 and clutch» The governor was installed "but made inoperative® This model Case engine is used in:/

farm equipments saw mills@ oil fields 9 rock crushers 9 and

■' pumpingo 'V ^ r ' ^ Z/r. Vl' V, 't 'f/ ' 1 v/ . The dynamometer consisted essentially of a direct •

eurrent generator mounted in bearing trunnions with a- lever .;:arm.:.eonne©ted,.lo a balanee. sealeo In this type equipment • the reaction of the stator is:equal and opposite, to th e

torque exerted on ■the armature, which is driven by fhe I-':-■.,,,

engine e Th,e react ion of the stator or dynamometer load .

Was' measured by a lever arm and balance scale 0 .; Generator /.

o u t p u t : was: dissipatedas heat in a large bank of resistanees 0 For starting the test roa chine direct cur rent was supplied, to 'the:' dynamometer which d'aus.ed the generator to act as :U 'y v 5IGUKE 1

TEST INSTALLATION m stbr ' and. to ro tate the - engine o . , ■■ ■ Stigine cooling water was supplied.from'a separately driven auxiliary ptpap delivering water from a sump tank 6 Water from, the supply main could also "be mixed with the sump water in order to provide;excellent control of the : range of inlet and o utlet-©obling water temperaturese Kiel consumption was measured "by the "balance scale and stop-watch method for liquid fuelo This method was used for. liquefied-petroleum gas alsog as it was weighed in the liquid stat e o' Hatural gas oonsumption was measured hy a size two standard gas.meter and stop watch« ■ . , - Air-fuel ratio was taken for individual cylinders by the use of -j—inch sampling tubes leading from each exhaust port through valves to a Cambridge exhaust gas analyzer» The sampling tubes were inserted through the exhaust mani*= fold and led to the center of each exhaust port 0 - The same ; anaiyzer was used to obtain the combined air-fuel ratio in .■ the' main exhaust pipe at a; point,, approximately five feet from the engine exhaust manifoldo ; : - • - .T Engine revolutions per^minute were obtained by counter; and stop watch and taken in conjunction, with fuel measure­ ments o The cbunter was started and stopped by a solenoidV that was actuated by a remote switch located at the fuel 1 measuring scales 0 Sals setup permitted accurate synchronir' sation .of fuel and speed measurements 0 Cylinder pressure date was taken using the Qox D ir e e t leading'Pressure indieator O^pe 9o Shis instrument con­ sisted essentially of a synchronizing uBitg gauge beard and

sampling element o The sampling element was inserted in the plaee of the.spark plug and provided ignition as well as gas sesipling fumetionso The instrument wa.s synchronized to: the engine erankshaft and provided direct pressure readings at ■ any■ point-in the engine eyeleo The spark advance setting was measured by equipment

attached to,the dynamometer for this special purposeo

Engine ignition spark was fed through a slip ring to a pointer on the rotating dynamometer shaft a Spark from -

the pointer marked on a diso so calibrated that ignition timing could be read, directly» With the engine running the magneto was rotated in relation to the crankshaft umtil ■the ,desired spark position was obtained« This permitted dynamic adjustment and measurement of the spark advance settinge■

/ , ■, -Inlet manifold:.,vacuum was read- on a bourdon type vac­ uum gage and inlet -man ifold temperature was read.on a.mer­

cury thermometer a Gasoline octane number was obtained by the Cooperative. Euel Research motor methodo A sling psy-

ehrometer and aneroid barometer were used to determine atmospheric conditions .0 Ambient, vair temperature could not be controlled o -Gil sump temperature was measured with an

immersion bulb distant reading thermometer aecurate to w ith in ©ne p e r c e n t ©f s c a l e 0 Inlet and outlet water,

■ temperatures were indicated hy mercury thermometers 0

4 1 1 meters and gages'were aeeurately ealihratedo -- ; OMHCSR 111

TEST PROCEDURE

o f T e s t b.o Three Uasie types of tests were employed in order to compare performance data obtained under -various conditions of engine operation o These tests consisted of full=throttle tests with variable engine speedy part-load tests with variable engine speed® and constant-speed tests with variable engine Ipade For the constant”speed runs 1550 revolutions per minute and 1700 revolutions per minute were the chosen speeds = These speeds were seleeted because when the Case engine is operated with a governor 9 1550 revolutions per minute and 1700 revolutions per minute are the recommended operating

Engine Conditions a Prior to starting a \ - test run considerable effort was made to-standardise ' engine operating, conditions 0 This was done in order to insure an accurate comparison of the effects of changing a test component such'as the fuel or manifoldo The engine was started by allowing the electric dynamometer to act as a direct current motor to rotate the engine 0 At an 'engine speed of approximately 500 revolutions per minute the ignition switch was turned on ands as the engine commenced f i r i n g 5, the dynamometer was switched, to act as, a direct current generator and serve as a "brake or load on the ' .. ■ ; engine * The engine was run in the s^eed range of 800 to /'* 900 revolutions- per minute for a warming period until

-operating conditions stahilized® The water temperature

. "Was drought up to and maintaire d: at ,appr 6 %im a te ly 1 @0 ° : ■ Fahrenheit on the inlet and 160 ' Fahrenheit on the outlet 'watero This was accomplished hy using a combination of tap . water and re=eirculated water as .a coolant e' Proper mixing was obtained "by adjust ing hand operated globe valves to " ; ; ' obtain the desired cooling w;ater-temperatures as engine ' output was variedo The temperature of the oil in the sump was .allowed to come up to about 170° Fahrenheit before tests ;were started o This served to -keep oil sump temperatures within a narrow>range durihg tests and/helped to minimize

any errors due to varying engine friction caused by oil viseosity" ehanges o . : ■ Fuel Mixture ^Controlo The desired air^fuel.ratio was -

obtained hy .adjustdhg-;;-^e'..--iaixttire. Control for each fuel and manifold tested a,nd taking reading's" with the Cambridge - ■ > - ekhaust gas analyzer? The air*-fuel ratio adjustment was made

in each instance with an engine condition of wide open

^■:;'1^r@btie-;ahd:lbi0tr^Q lutlohs--per minute» Ho. change was made in the mixture set ting during a'run although the air-fuel rat io did vary during: the te st» The engine instruction manual. supplied, by the .manufacturer was used as.

a guide to the. proper setting of- the air-fuel ratio» . The fuel mixture was set slightly leaner than the maximum power condition in order to-gife good power consistent with'econo- my of operation o Eaximum engine power was developed with a rich mixture hut the engine hecame comparatively expensive

to operat e a By making the fuel mixture slightly leaner and ; sacrificing a small part of the maximum power output obtain­ able, the fuel, economy:, could be substantiaL ly increased = It was also possible to obtain even greater economy by using . quite lean mixtures but this was not advisable because of ■- •

the attendant, undesirable features of considerable loss in : .

power and' thevpossibiilty of burning the exhaust valves 9

: H en ce 9 the choice of air-fuel ratio was carefully made, In

the case of the Gay manifold using the Pord 6 © carburetor the mixture setting wa,s hot varied because this carburetor

had fixed jets and no mixture setting device was available 0 ~ Ignition ‘Timing»' The Case engine used a magneto for .spark Ignition,. The spark advance setting could be changed by adj ust ihg th e ^ magh e t d o hut dma ti c spark advance equipment was not installed' as standard equipment and therefore not

used. The ignition timing was. set - to give optimum perf ormanc

for each different fuel useda -■" p.',: - ::' Description of Test Runs@ W ith.the engine properly

•warmed and o.perating,conditions fairly stable the desired

speed and load for a test were set. For all tests 9 p r i o r to : taking datap the engine 'was allowed to run at or near the

desired setting until temperatures leveled off and minor ■ 12 load adjustments were made in order to obtain equilibrium eonditions»

For the full»throttle tests with the throttle set wide open the dynamometer loading was varied to obtain the desired engine revolutions per minuted Dynamometer loading or braking effect was varied by changing either the shunt field resistance or armature resistance or botho Complete sets of .data were taken from 900 revolutions per minute to 1900 revolutions per minute in increments of 200 revolutions per minuteo These tests represented, maximum load condition for each rotative speed 0

Fait-throttle tests were conducted with the engine load set at 70 per cent of the maximum load for each speed® To accomplish this for a certain desired speed 70 per cent of the maximum load obtained was calculated and this value set on the dynamometer beam scale® By carefully manipulating both the engine throttle and dynamometer loading controls 8 the desired rotative speed, was set and at. the same" time the dynamometer beam was brought to the balance point at the desired scale reading 6 This procedure was followed and data taken for the 900 to 1900 revolutions per minute speed range in increments of 2 0 0 revolutions per minute 6

Oonstant-speed tests were made at 1§50 revolutions per minute and 1700 revolutions per minute 0 Five steps from no load to full load, were selected in order t© give smooth curves when plotting the data 0 F o r a l l ©xeept'the ftill load point the throttle and dynamometer

load control had to he adjusted -simultaneously in order to reach the desired load setting and maintain ©ohstant speed* The time of starting each run was set hy the watch timing the fuel consumption, A switch at the fuel measuring station th at' controlled operation of the .reyelutlom counter was operated; simultaneously with the stop wateh, Each test ■ was ended when fuel consumption measuring was completed,. ■ Mhimum time for a run was three minutes, Most of the

tests required a longer running time in order to measure a large enough quantity of fuel to insure accuracy of.I , measurement . Two operators were used in order to read and , ' v: record all the necessary data yrithin a reasonahle time internal* . : ' Jgata readings'were taken: on the following items g time of run$ dynamometer load $ total revolutions, amount of fuel usedj cooling water inlet temperature, combined

air-fuel ratio, manifold .vacuum, oil sump temperature, individual cylinder air-fuel ratios, individual cylinder pressures, spark timing-, barometer reading, amhient air

dry-bulh temperature., and ambient air wet-bulh temperature*- i

. 0 bserv@,tlons were made where appropriate as to smoothness : of engine operation, knocking, and the behavior of the ■

fuel charge inside the rake and Gay manifolds as-seen ' - through the plastic windows» ’• . it ■ CHAPTER IV

. P M S ahd P eril co sts / J

- Gasolinea The primary reference fuel for this study -

was gasoline-, Jit was chosen "because approxime,tely 44 percent of a ll petroleum products are ■ marketed as gasoline { Regu-=. lar grade gasoline having an octane tiumher of 72o2 as determined "by a;. Cooperative Puel Research motor method.: test was used for all runs requiring gasoline„ ! . ■ Gasoline Costs-, Por Tucson $ / Arizona and vicinity as of this writing, three major o il Companies quoted■ SS-g Cents per gallon for regular grade gasoline: purehased in SO©-406 ' gallon■ lo ts«, This figure ineluded a State tax of five cents which may be deducted f or non-road use

; Kerosene-, Pormerly 9 kerosene was the fuel of choice : for farm equipment use-, There were two reasons for th is» {l); It was cheap and readily available| (2) Its low vola-

"tility made it a.relatively safe fuel to handle-, The first mentioned, advantage for herosene no longer exists because'it has increased in price with respect to Competitive fu els„ Kerosene may -be purchased somewhat'

cheaper than gasolineghbut■ 'the small price differential is '

Edward Fa Obert> ,Internal Combustion Engines 3 (se co n d editions Scranton ;9 The International TextbookJJompany 9 1950) f -. mo%e:than offset by the loss of overall economy due to

in#feased mainterianoe costs when using kerosene 0

Kerosene has some distinct disadvantages in comparison with the other three fuels tested § • |1 J Sfeximum en'gine power output is markedly reduced; (2) kerosene cannot be used to start a cold engine| (3j crankcase oil must be changed more

frequently; and |4) maintenance and overhaul ■costs' are highero .. ■. - -.'.t-' ;. ■ • ■ . Kerosene Costso The lowest price quotation of three

major companies for Tucson 8 Arizona as of this writing was

19 cents a gallon for kerosene purchased in 2 0 G to 400 gal­ lon lots =, If road use is intended 5 cents must be added to the price per gallon for State tax® . hiquefied°-Petroleum Gas o Butane and propane -= lique- fied-petroleum gases - are generally referred to as BP-Gas® The term is a general designation of butane or propane or a mixture of botho^ LP-Gas is. one of the liquefiable compon^.

: ents Of "Wef " gas 0 This wet gas comes up- from the earth. ■ : with crude oil and is immediately-separsfc ed at the well or

v easing heado Wet gas is produced 9 toos from most natural gas wells® The casing^head gas goes from the oil well

either to a cycling .or natural gasoline plant® The wet ■

. ' — BP-Gas Equipment 9 Operator*0 Instruction Manual® ' firs t edition® J® I® Case Go.® 9 R a c in e 9 Wisconsin^ p® 3® natural gas goes to the- latter= Both plants strip out the propane~hutane eomponents= R efineries.separate propane

and "butane in the process. of refining crude oil 0

Bany elaims 9 counter clalins 9 and predictions hare • "been made - regarding IP-Gas „ ivh ether BP-G asis the motor

fuel of the future» a Mflash in the pan p”. or something in

"between is yet to he seen! ■ Partioula,rly in areas where 'BP-Gas'is cheap and plentiful there is a definite:trend

toward its use in place of gasoline« In 1950 some 50§000 to 75«000 conversion- units were made on farm units§ equal :

to ah out 10 to 15 per cent of all tractors huilt f or thatv

y e a r : v Some advantages that BP«Gas possesses over gasoline

areg - - % :V pi' ." 'y;;"'.. : ■ -y- ;{1): Higher octane: ratings ; BP-Gas has an .octane \ rating of . lOO^plus compa-red to 70-75 for regular grade

gasolineo In addition the higher octane rating allows the use of higher compression ratio with increased efficiency

and p o w er, i t x ! ! - '' t T t-' ; ; - V' "

: ; (2) More nearly complete combustion 0 ■Since BP-Gas

enters the; engine as a vapor § : its comhustion is cleaner' /

than that of gasoline which -enters as a liquid and is

Red Horse § 17 g11 § March§ 19520 • - vaporized as it' leaves tBe carburetoro ,

(3} Minimum of crankcase dilution * This increases the length; of time allowed "between Oil changes» : ; |4) Reduced carbon deposits9 Gleaner burning results in less carbon being left on pistons s rings9 cylinder walls and valves @ . -• , , ' I :

• .;C:b| Songer time perm itted between oyerhauls 9 This : . .

comes a-s a" result of f 3 .j:-a n d | 4 ) ' above:0;- / ; y :': ; ■ The tests conducted in this project were aimed at making further investigations of the possibilities Qf lP==Ga,s particularly for the Southern Arizona area & " . ^; ; - . ; liquefled-Petroleum Gas Costs o In the TucsonArizona a r e a s as of this w riting9 IP^Gas Could be purchased •f or approximately 14 - cents per gallon when purchased.for sta- -

tionary engines or farm use in lots of;about 500 gallonso If puichased:for road Use five cents' a gallon State tax must be Added to ■ the cost per gallon» . 'V i y v: i. •: ' ■ ;: ;

'' liatural _Gaso natural gas {largely Methane$, 'CH 4 ); i s an

excellent fuel for.stationary engines! Based on heat con­ tent natural gas is a comparatively. cheap fuel <> like LP-Gas

it has advantages over gasoline ofg ( 1 ) higher anti-knoek

value, (equivalent to lOO-plus octane rating) 9 ■•(2) minimum arankcase /dilutioh; -(3) minimum carbon deposits! and (4) more /nearly complete combustion = In addition;... natural gas h a s : th e: /a d v a n t ag e ■ p ve r : any -' 1 1 quid/fuel/in that it offers no

fuel storage problem,, Inexpensive cut-off devices may be Y — ■' ./r-. - :1@ installed as a safety measure for unattended eng-ines0 ^ A disadvantage of natural gas is that it produces only' ahout 80 per cent of the power that may he expected

from gasoline0 In an engine that uses natural gas exclus=o ively this could he overcome in parthy increasing the

engine compression ratio and hence the power output and

■ efficien cy a'. •: .;: t/:i i' ■ ^ :';; Patural Gas• Costs0 The cost of natural gas’ depends

upon . the rate for the locality and varies .rather; widely . depending upon the use and amount;purchased^' The price may run from two and one-half to six cents a therm (100 9.000 B rit ish - Thermal Units.) 0 The cost of natural gas used in preparing the graphs for. this' thesis is abased on ' the rate schedule for the Arizona area established hy the Central Arinona power and Light Companyo ■ ; ’ - . . ; g ib p ™ t

. :;i^mEE Hpiso^ \:L '\:i; '

.• Experimental tests were made on the Case industrial 'engine using four different ty^e-s of intake manifolds 0 Bata were taken to investigate engine performance factors of power output/ specific fuel consumption$ fuel and power

distribution among cylindersp and smoothness of operation0 The Gasoline Manifold (Figure 2]0 This was a stand­

ard equipment manifold Supplied by the manufacturer for engines using gasoline fuel only0 The carburetor flange ' was a: one inch nom inal,s.ise.: CSoelety'• of Automotive Engineer's standard) for.updraft operation^ The construc­ tion was cast iron with fairly well streamllne% Intake and distribution passages Q The intake manifold- was cast inte- gral with the exhaust man if old.=, The two - manifolds were joined in the oentral portion in such a manner tha,t the

heat from :the. exhaust provided heat ..to the\ intake, mixture.® There was no; provision for heat regulation9 however$, and

although s tar ting : and engihe warm- up' a re fa c ilita te d * , a : ■ loss in engine efficiency occurs due to m ixtureheating after the engine reaches running tem perature» fT'n; Comparison with the . other three tested^ the gaso line manifold- placed " third in. regard t o maximum power ■ outputs and second in / - •

regard to minimum specific fuel consumption<, . With th is 5’IGUKS 2

CASji GASOLIHE lAHIFOM) man if olti.. eyl ihd. e r s' on e and three produced about the same power with cylinders two and four considerably.weaker^ • V ; Power distributldn for this manifold was investigated with the oarburetor rotated'ISO degrees: from its normal . positione The 'reason for this was to investigate the' . effect of the throttle itself on the flow of the air fuel mixture0 A shift in power distribution occurred with cylinder one supplying the most powerp cylinders three and four slightly less9 and cylinder two the least power@ The V oyer-all distribution was about the same for the carbure­ tor in either position0. A '• /A %e Combination lan if old (Pigure g)0 This Intake manifold was of a type furnibhed by the engine manufacturer as optional equipment o' l>t was intended prim arily for use With “inferior grade motor fuels such as kerosene but could be used with gasoline fuela The. manifold was of cast iron construction and cast integrally with the exhaust manifoldi The intake passages were fairly well streamlined and a / : large' "hot spot!' Was provided at the center of the junction between the intake and. exhaust man if o Ids» There was no ; : provision for heat 'regulation and heat ing of the air fu e l: mixture increased rapidly as ' the;' engine' was p u t: under loado.

;. The large amount of heat added to the fuel mixture had an.adverse.effect on the maximum power from the engine and : consequently this manifold proved to be the poofest On that basis o. Heating the air-fuel mixture brought about a MGUM 3

CASJi COMBIHATION MAHIPOLD , 25

decrease in density of the entering air-fuel mixture and thus a drop in volumetric efficiencye A loss of power

would then he expected since less fuel charge would enter the cylinderso The heating of the mixture was a hoon to

fuel and power distributions however^ Better atomisation

of . the fu el, with ties s fuel ©titering .the cylinders in . liquid form gave not only .good distribution^ hut excellent specific fuel consumption as wello 1-n the matter of fuel

economy with liquid fuel this manifold ranked first compared to. the other manifolds tested» The Gay Manif old: I'ffigure 4) 0 This intake manifold was of the downdraft rake type with no provision for mixture

heatingo It was constructed of thin wall steel tubing and designed to be used in conjunction with a Ford 60 carburetor The Gay Manifold was used in these test’s in order to compare the relative merits of the downdraft and updraft 'methods of carburetion0: The increase in power afforded by .this manifold was noteworthy9 particularly at the higher speedsy despite poor power distribution among cylinders» ;

The specific fuel consumption:of the engine when using the Gay Manifold was relatively poor» .This performance factof could probably be substantially improved by modifying' the mixture control system of the carburetor#

- npdraft Rake Manifold fFigure 5l_0 . This manifold was designed and fabricated in order to test directly the "rake"

principlef advocated by Gay, on an updraft type manifold in FIGURE 4

GAY IIAITIFOLU 25

FIGURE 5

RAKE mUIFQLD eomp&ris©n -v/i ill updraft intake manifolds suppli ed "by the

engine raaimfaptta^er o:^ - • / - - : , : . : / In the faiarieati on of the updraft rake manifold tliin= walled Steel' tnMng was used for the fis er9 header and .

dis trihut-i on sections » Hi Id steel flanges for the car- . huretof and intake ports were welded to the steel tuMngQ. A three-inch huffer:extension was provided on each end of the main header tuhes Clear plastic was used to seal off the ends of the- "buffer extensions^ By putting s, light at ■ .

one end of the ipain header • and viewing from tiae other end throu#i the plastie window^ the: action of the fuel mixture"

:hould he .ohserved« The ;plasti© windows eouldbe replaced hy metal plugs of various lengths, so . that the si ze of . the;' buffer; ext en si on could he altered by installing . ' different length metal plugs« fhe; rake man if old Was ' .

designed as "a ©old im nifold with no provision for mixture heatings -In contrast with the gasoline and combination manif olds the rake manifold had ho connection to the exhaust manif olde ■ -p : .. . ' "h

The rake ipanifold proved superior on a power output basis to the manifolds supplied by the manufacturero It gave more power at lower speeds than all the manifolds

t as ted a but at the higher speeds the Gay. downdraft manifold indicated the highest power output @ : - - - Speeifie fuel eonsmnption v/as higher with the rake :- m nifold than with the gasoline or combination manifolds0 This proved true "both for fnl 1-throttle and part=throttle

operation o; .; ■ , ■ - .1 ■ ■ The 0ox indicator showed that distribution in the rake manifold was poorer than in the manifolds supplied by the manufaeturero It. was hoped that the. rake feature would provide good distribution despite the lack of mixture heat= ingo; .Tisual dbservations in the manifold indicated that fuel distribution would be poor as pools of liquid fuel eolleeted in the main-header a Various ideas were tried, in > an effort to improve the fuel distribution with the rake manifoldo The main header was: altered in shape so that if curved up at the ends but little change ws.s found in the- . distributionT he buffer extensions were varied in length from three; inches to zero but this was of little avail0 DISCUSSION m ' PERFOmiAnCB DATA

The or part of the data taken "by experimental test : has heen plotted and presented in graphic forme The curves .

.are 'arranged so^ ^ comparison pmrpOses and also for individual analysis'o -y- Figure 6 gives a comparison of the full-throttle power : output for four;fuels--gasopine9 kerosene9 XP-Gasand. natural .gas' The gasoline and kerosene runs were: made-under optimum conditions for the fuel Used<= The DP-Gas and natural gas runs indicate the power •ohtained hy ©hanging only; the earburetion equipment 9; intake manifoId. and spark advance o ■ ' The oui've for ■ gasolihe follow s ■ closely = to a straig h t line up to l7©6 revolutions per mi.nute wh and tends to flatteno LP-G-as gives the second best power and ; it follows the pattern of the gasoline curve* LP-Gas ■ - : indicated; about: ten .per cent less power than gasoline: - throughout the speed range tested! : t ' Natural ga,s produced about SO. per cent less power than

gasoline & The curve f or natural gas "breaks rather sharply ’ around 1660 revolutions per minute» This marked, drosp; in the.; power curve suggests possihie earhuretioh troubles0 Since DP-Gasy,was: adm ittsd . t oi the: engine w ith the ■same, carburetor as.- the m tural gas a- the pressure, regular or system. ap pears Brake H orsepow er 10 15 38 25 30 40 800 RJi HRScwR ^L2 for four different n e r e f f i d r u o f r S^2L*2D o f s v HQRSSrcrwURBRiJCii th throttle set wi opon e id w t e s e l t t o r h t h it w s l e u f 1000 o i e lin o s a G — -o uti nute u in M r e p s n io t lu o v e R 1200 IUi 6 FIGUIiE 1400 1600 ■ u 1800

29 2000 to t>e tke most likely source for the irregular natural gas eurTeo Redesign of tke pressure regulator system; should bring the natural gas curvesupto the pattern, of. the other * * curves'o ' ' :V ; ■ It may be noted that kerosene gives relatively ■weak power outputo Compared to gasoline a loss of up to 25 per dent in power is indicated. The weak showing of kerosene ■ may be attributed to poor atomization of the fuel and poor .

'eylinder distributiono Cylinder pressure data revealed a ' - power varianee among cylinders of as much as'25 per cent @ In Pigure 7 is depicted the specific fuel consumption

information for gasoline9 kerosene and IP-Gas. This is for the full«= throttle oonditione Satural gas is not compared beeause consumption of it was.measured in cubic feet while ' the other fuels were measured in pounds. : \ bP^Gas gdve the minimum specific fuel .consumption curve within ';the normal engine operating range. It was quite high howeverj> rat lower engine speeds.. Should it be desired to operate the engine in the lower speed range with this fuel,

a change in the carburet ion and pressmre; regulation system ; would be highly advisable. "

The best economy point for kerosene for full throttle conditions was near 1500 revolutions per minute. Engine' performance was poor at full throttle above 1500 revolutions

per minute with higher fuel consumption, noisy operation : and high oil sump temperatures. \ Pounds of Fuel per Brake Horsepower Hour 800 900 700 400 600 300 500 800 SEBCIFIC SEBCIFIC open hree different t n e r e f f i d e e r th 1000 ti COFSUMPTICU FtriL

A - uti nute u in M r e p s n io t lu o v e R 1200 s l e u f IUE 7 FIGURE th throttle e l t t o r h t h it w 1400 s v PS (RBC) SPiSD &0 1800 1&00 t e s de id w r o f

2000 31 The sgeoifie fuel consBm.ption curve of gasoline was good and reached, a minimum point ; around 1600 revolutions per minute0 Although the gasoline curve was higher than that for LP=Gassit must he kept in mind tha,t LP-Gas wei^is much less

.per gallon than does gasoline0 - Qn figure B is shown a "power comparison for ,gasolines, kerosene and ^^Gas with the engine operating at 70 per ;: cent load at various speedso The general pattern.of the part-load curves follows closely to that of the full- ^ : ' throttle condition0 The natural gas curve again exhibits' its peculiarity of having a marked droop "beginning at 1600 revolutions per minute» . • figure 9- shows the part throttle specific fuel con­ sumption curves for gasoline g; kerosene-and lil-Ga.So The curve for gasoline reaches a •minimum at 1400 revolutions per minute and is nearly flat in the 1400=1600 revolutions per minute rangeThe kerosene economy curve dips near ; 1100 revolutions per iminute 'hut rises -rather rapidly . thereafter0 The fuel consumption for IP-Gas is excessive in the lower speed ranges, hut ahove 1300 revolutions per minute it goes doWn rapidly and reaches a minimum around - 1800 revolutions per minute® Here again it is ohvious that the fuel admission equipment needs revamping for XP=Gas if / speeds helow 1500 revolutions per minute are to he used® figure 10 depiets. the specifie fuel consumption for gasoline, kerosene and XF-Gas. under constant speed Brake Horsepower 35 30 20 16 10 800 RK HRycJm Q PTI (Pi for four different t n e r e f f i d r u o f r o f (HPri) SPIT.ID VQ HORaypcyJim BRAKa t 0 l d a lo t n e c r e p 70 t a t e s e l t t o r h t ith w s l e u f 1000 Revolutions per per Minute Revolutions 1200 L- aa -LP-G ! gas Natural Kerosene Gasoline IUE 8 FIGURE 1400

60 1800 1600 2000 33 Pounds of Fuel per brake Horsepower Hour 000 0 .0 1 1.100 .500 .600 .700 .800 .900 800 PCFC UL CCSTSUt-rpTlO^T FUEL SPECIFIC ih throttle sot t a t o s e l t t o r h t /ith v s l e u f t n e r e f f i d e e r h t 70 70 r e p 1000 l d a lo t n e c

£»— uti nute u in M r e p s n io t lu o v e R 1200 x " - x — '— IUE 9 FIGURE a — • ro eno s ro • — 1400 ■ — G&Aolins ■ G&Aolins — v s s v 1600 PS (mr) for o f ) r m ( SPHSD X A 1800

2000 34 Pounds of Fuel per brake Horsepower Hour 700 0 .7 1 500 0 .5 1 1.100 900 700 500 i r e f f i d e o iir t r o f J FI LTMmon vs v n o m M T rL c c , n e s IC lF rJC b 15 rpm 1550 f o 10 ae reo er orsepow H rake B o u t t u o FIGUPJ5 10 d e e p s t n a t s n o c t a s l e u f 15 20 —f 25 i- 35 30 eohd.itions with variable loado 'Up to 50 per eent load. the three fuels run close together in the amount, of fuel consuiaed per brake horsepowerthour o Above 50 per cent load l»P“©as is "bests giving the least specific fuel consumption = Kerosene had the poorest fuel consumption being as much as

SO per cent hi^ier than iP^Gas« ' ; h t . Kigure 11 gasoline, and kerosene are compared: on a ;: specific fuel consumption basis for the conditions of a " .constant speed.of 1700 revolutions per minute and variable lo ad o : In: these runs gaso 1 ine and kerosene are used under ' Optimum conditioUs for each© Intake manifolds best suited - to each fuel were used, The & ark advance .was. regulated ' for best performance for e.adb. fuels ...’Kerosene proved defi^ nitely inferior to gaso line from a specific fuel consumption

V le i^ o ln to t : ■ : .. * .■■■ .' " ' ■ ■ : t '' keur .different intake manifolds are compared in y i’igure lg: for power output using gasoline fuel o These tests were run at full throttle with variable speed» The ©ay downdraft manifold gives the most power output when the engine is operated above 1400 revolutions per minute0 The

curve for this manifold is approkimately a straight line with no tendency to flatten at any of the observed, speeds 0

This is: due to the large size and reduced restriction to - flow offered by a large downdraft manifoldo The- updraft , rake manifold shows the second best power characteristic0 The extra power with the;rake:manifold over the gasoline, and Pounds of Fuel per Brake Horsepower Hour 1.100 300 0 .3 1 500 0 .5 1 700 0 .7 1 .500 .700 .900 5 0 5 0 5 50 25 20 15 10 5 0 m a m m m m tm rnnu PCFC UL 5UT# 0 V HA> S X O ^ S R O H HIAB> V3 I05 #T T 05SU C FUEL SPECIFIC vo o yc oeBrt pee ed e sp rit oonetB c y lo o u f c n e r e i f l d tv/o r o f f 7U ip^i 17GUof n.ii .mii.w ■ , ^ , w.w ** ,###«, m hmm— ae Korc©power rake B »iu ■ ' n » i i g> > ^i m f f c .f r » vru * r « —1~ m n t i B y v w r n t * m» m. if — «*. 37

Brake H orsepow er 10 20 15 25 30 35 5 0 1300 800 i Masioit fur‘ r u o ‘f r u f s v a.siipouizt M ai; w m ake iu- f ds n^ gasolne e lin o s a g ^ in e u s id ifo -n iiu e k ta n I t n e r e f f i d t d open ide w t e s e l t t o r h t ith w l e u f 1000 utons per inute M r e p s n tio lu o v e R 20 1400 1200 —a —rGy f ld ifo n a M Gay r — x — o j ae f ld ifo n a M Rake j o - ■ IU2 12 FIGUR2 a ------f naton ^f f ld ifo n fe ^ n tio a in b m o C -f - Gas i f ld ifo n a M e lin so a G r 1600 38 2000 eoiabizi©,t'ion manifolds is attributed to the lack of "hot spot” dri the rake manifold,0 The cold manifold would give hettef volumetric efficiency because a denser fuel mixture is admitted to the cylinderso: This is particularly notice­ able at higher speeds ° The combination manifold sh ovrs th e least power and it may he noted that it is the hottest

manifoId under operating conditionsc . It is designed pri­ marily for operatioh with kerosene P hut still has a: satis­ factory operating characteristic with gasoline= The margin of diffeienee in the power output with the gasoline manifold and combination manifold is actually sm all? being about three per cento If this small loss in power

Can he tolerated the combination manifold is the preferred manifold because of the better fuel economy it provides. figure 13 shows how the specific fuel consumption of the engine is affected by four different Intake manifolds undef conditions of variable speed and full throttle 0 The

specific fuel economy of the manifolds is in inverse order of their power outpute The combination manifold exhibits the minimum specific fuel consumption<> but it delivers the least power outputo This, indicates that the selection of the intake manifold is a compromise in 'the goal of maximum power and minimum fuel consumptiono The curve for the day manifold is rather erratic and does not follow the pattern of the other curves0 This is probably due to the metering

characteristic of the Ford 60 carburetor used with, the ■ Pounds of Fuel per Brake Horsepower Hour 000 0 .0 1 .400 .500 .600 .700 .800 .900 0 10 10 10 10 1000 1000* 1400 1200 1000 800 four different intake raanifolds • Gaooline Gaooline • raanifolds intake different four ul sd ih hr te st ie open. wide set ttle ro th with used fuel for UZJOIFIO COliOiFI-TlGU FJIL ORJUD vs a- - X _ Gas i nifold an M e lin so a G } o t .KO O K l. J . a U i t . U U -t O ^ - -]• Combination Manifold Manifold -]• Combination - ^ a- eouin pr Minute per Revolutions - f Rake M nifold nifold M Rake f - —I- Gay M&dif old 't2k- IUE 13 FIGURE t — — X . X U L t M '' -B p ; x k- . -U -k V — —z>,- e- e- ' a 2000 40 Gay iianifoMo Ihis eatbaretor is not designed or matehed • SGirreetly to the Case engine and hence erratie results may - ■foe expeetedo The Ford carburetor generally gave too rich a .

iaixiuase as was: evidenced from the low air-fuel ratios oh tain ed with the Cambridge exhaust gas analyzer o At some speeds the air fuel ratio was less than ten to one 6 . • In figure 14 is shown a eomparison of power output from the engine as affected "by three different intake mani= ■'■foi:dS/o;.,;.';This is fo r the p art -thro ti l e c ond it ion of 70 per cent load with variahle engine speedso : The results of these tests follow closely the relationship between manifolds found on the full-throttle funs o Best in power output 3s - the rake manifold followed in order hy the gam line and combination manifoldso The pattern of the power curves is quite similar with the droop in the power curve coming;near 1560 revolutions per minute in each caseo :r -'1 i’igure 15 depicts the different specific fuel eonsump= tion Curves given when using gasu line fuel with the throttle set■for 70 per cent load at various speeds6 The.least

specific fuel consumption was shown by the combination mani­ fold followed by the gasoline and rake manifolds in that

order0 The curve for the rake manifold was rather . Irregular with a dip occurring at 1300 revolutions per minute and a sharp rise- appearing at 1766 revolutions per minnte = These irregularities are believed due to the poor vaporisation

eharaeteri stic of the cold rake manifold in addition to ■ Brake H orsepow er 15 10 2C 800 LC o i tuurec r o l ) i iir ( vo TLUC C il'ierent i u .;••.*ke manifolds using gasoline gasoline .;••.*ke using u i manifolds il'ierent C fu el el fu t at 7 rer cent oad a lo t n e c r e r 70 t a t e c e l t t o r h t ith w utons, Mi te u in M r a i , s n tio lu o v e d 1200 IUti 14 FIGUltlii 1400 mbnto IWifol ld o old iif W I bination om C Gratoolixie .d,ke Mfcnif Mfcnif .d,ke - - - - - * old 42 Pounds of Fuel per Brake Horsepower Hour 1.0CC .900 .800 .(300 .700 .400 .500 O 10 10 10 IO Iv 2000 IcvO IbOO 1400 1200 1000 oOO ng gasolne fuel wih throttle set t e s e l t t o r h t ith w l e u f e lin o s a g g in s u 0 l d a lo t n e c r e p 70 t a cio different I ake . fol s ld o if n a . e k ta In t n e r e f f i d fcJiroe r o f oii a::) .a ( iiiD o s v o n i c s i s vl inB psi Mluuby i s p B tion evolu R Co iai Hani' d ld it'c n a H n binatio om C - ar Haniol j ld ifo n a H Ralrc tfdii HnIf d id d f I Han Gttfodlixie A- 43 tmeveii distribution^ An analysis with the Gox indicator on this manifold showed comparatively poor power distribution ;

■between eylinderSo- In the test graphically illustrated in Figure 1© the "

- part-throttle specific fuel consumption eharaeteristie of the gasoline and combination manifolds were compared using ,, gasoline fuel in eaeh instaneeo Die curves show that there is about three per cent difference in the specific fuel .- consumption between the two manifolds under these conditions o In Digure l? is shown a, comparison of the effect on engine power output of using two different manifolds with natural gas as fuel» In, these tests the feasibility of using a cold manifold for the gaseous fuel was investigated0

In view of the fact that a denser fuel charge may be admitted to the engine with the cold rake manifold it would be expected that more power would be. produced with this manifoIdo . Sowever,■in comparing the rake and gasoline 'manifolds the physical characteristics of each must be considered in order to get a true picture of what takes ..placee.. While-a rake manifold offers the advantage of being ra colder operating manifolds, it does not have as stream­ lined a flow passage as does the gasoline manifoldo: Hence there are two opposing factors at work0 > I t may be noted that at the lower speeds the rake manif old curve is higher in power. While above ITOO revolutions per minute the gasoline

manifold curve is the: higher0 Dais may be e^lained by : : : Pounds of Fuel per Brake Horsepower Hour 500 0 .5 1 1 700 0 .7 1 . 900 100 700 * zj Fi rL: .; s v i.:; v r :- L ir o c io iF jc rz s pee 15 rpm 1550 f o ed e sp f o r t'./o d i f f e r e n t in ta k e :.ia n ifo ld s a t c o n s ta n t t n ta s n o c t a s ld ifo n :.ia e k ta in t n e r e f f i d t'./o r o f 5 10 piguill reo er orsepow H 15 mbnto Maniold ifo n a M bination om C -toij Maniol ld ifo n a M G-atiolirje 16 : 45 50 Brake H orsepow er 30 15 Ba&KS H C R G K Pa^ v s SE^ID (:UP%) f o r two two r o f (:UP%) SE^ID s v Pa^ K G R C H Ba&KS a fuel wih throttle oet d open ide w t e o e l t t o r h t ith w l e u f gae nt f ds usi l a r u t a n g in s u s ld ifo n a m e k ta in t n e r e f f i d covuva io /liv i b l / i-or Mcvolv ulvra- IUE 17 FIGURE Car i snIfoil Ms f d n I e lin ro a C t ae r fcl ! . l6 c lf n ?ra Rake -9 46 eonsideriBg that the streamline flow of the gasoline manifold 'ants, as the predominant factor and overcomes the difference / occasioned "by manifold temperatureo: The difference 'between ' the operating temperatures of the gasoline and rake manifolds ; decreases at the higher .speeds . This may "be seen graphieally illmstrat'ed fin' figure. Sit, ’ - - ; \

•:. -.To provide a "better design of manifold for use with natnrai ga,s :the cold temperature feature and the free flow design, should be combined. J, large as practicable^ stream.™ lined passages side draft type manifold without a hot spot' is recommended for use With natural gad, Shielding the , intake manifold:from engine and exhaust manifold heat might f well : pf owe worthwhileo : '. • .. : -' - "f p - ■: . S’igure 18 presents the specific fuel consumption for . natural gas under full and part throttle conditions at : ' .varying speeds. It may be noted that the part-*throttle specific fuel consumption is muoh higher than that for full

load. A bett er des ign of carburetor and •. pressure regulator would probably help the part-throttle fuel consumption to some extent. • ;.:. ; " . v: v, : ...

.. A comparison of two-; different intake manifolds with natural gas . fuel is . shown; in figure' 190 Specific fuel" :: '

eonsumption for wide open throttle conditions.is compared^ . at various speeds. At the higher speeds; the more streams ;

lined gasoline manifold affords better fuel' efficiency .than: the rake:manifold. Turbulence in the flow in the Cubic Feet of Gas per Brake Horsepower Hour 15 14 12 13 16 17 18, 800 u fuel usi w different throttle e l t t o r h t t n e r e f f i d two g in s u l e u f gus l a r u t a n PCFC UL OTTTIJ vs PL (P: for r o f (HP7:) SPELL COITSTTTTIOJT FUEL s v SPECIFIC s g n i t t e s 1000 utons inute M r e p s n tio lu o v e R 1200 I u m TIG 40 1600 1400 l ttle o r h T ll u F ' * 0 7 13 Load 1800

2000 48 Cubic Feet of Gas per Brake Horsepower Hour 5 1 17 12 13 14 18 800 n a t u r a l gae f u e l w ith t h r o t t l e s e t w ide ide w t e s e l t t o r h t ith w l e u f gae l a r u t a n w different i ake maniol ng g in s u s ld ifo n a m e k ta in t n e r e f f i d two r o f SK SCm O IU3L CaSSXTSTICB CaSSXTSTICB IU3L O SCm SK open 00 1200 1000 utons per nut. u in K r e p s n tio lu o v e R o - IU% 19 TICUK% 1400 rc M ifold o f Mr pi Eric® olne Maniold ifo n a M e lin so a G to 1000 SKiSD (EH/) (EH/) SKiSD IbCO 49 rake manifold is considered the reason for it not giving

"bettereffieieney o ' The colder. running temperature of . the rake manifold' should make it show up hetter hut apparently this good feature is overcome hy the poor flow : character is tie :6:.. Fuel and power distribution among cylinders is excellent with natural gas fuel as shown hy tests with the 0ox indicator e - .'L: --1 i' In Figure 20 are shown specific fuel consumption curves ■ for natural, gas fuel using two ■ different intake : -: manifolds under . eonditionS; of constant. spWd^andr: ,: , variahle throttle« Here the gasoline manifold shows up more advantageous than the rake manifold although the margin is smallg.heimg ahout two per cent® The pattern of the two curves #:quite similar,. The "better flow con- ’ ditions in the gasoline manifold seem to account.for its superiorityo . ■ -1 ■ \ 1 f' Figure 21 pictures graphically the .operating tempera­ tures of three different intake manifolds under conditions . of wide open th ro ttle and varying speed0 The.fora of the three curves is quite similar» It may he noted that the temperature of the imn if olds iner eases only slightly at higher engine power due to the cooling effect of the . increased flow of intake mixture as the engine speed w inereasea o-. , ■ ■ - ' " . .. . - : V ' '.; 3'igure # portrays graphically the relative merits of' gas oline ^ kerosene s iP-Gas9 and natural gas on the has is of Cubic Feet of Gas per Brake Horsepower Hour 30 60 50 10 0 fuel at const s d of 50 rpin 1550 f o ed e sp t n ta s n o c t a l e u f s a g l a r u t a n w different i ake maniol ng g in s u s ld ifo n a m e k ta in t n e r e f f i d HO.LBEPOVEH two BPJuTJ r ve o C0i:STJ!1PTI0Uf FUEL SPECIFIC 10 rki Tioz^aepower Fr&kci FiGira, FiGira, ae f d j ld ifo n a M Bake olne It fol ld o if n ta I e lin so a G 20 20 25 51 30 Temperature in Degrees Fahrenheit 175 1:.0 25 50 i t vi oron e id v t e n e l t t o r h t ith w l e u f e lin o s a g hree different i ake mi iol usi g in s u s ld ;ifo io m e k ta in t n e r e f f i d e e r th r o f 1T3U WTIOJ) 3%/LI#4 SJi (13?%) ) H iL J S S V 13Z%T/:LLIT#L4 JJ) IFO T TW I17TA3CU -Q .vlt m3 p. v -p'.r 3 m ?.?volut< 4

ae ld o Hake mbiain f d ld ifo n a K ination b ld om Mauio C f i GtiBolinb TUh 21 ZTGURh tO 10C0 jtOO 52 Cents per Brake Horsepower Hour ui IXtelti L a a r e f if u CV32 i u o f & a r r o f IIIG iC K S R e v o lu tio n e p e r r e p e n tio lu o v e R FIGUIlal d - N a tu ra l l ra tu a N crotiene K Ge.L.olln& Ge.L.olln& 22 O H3 f3") ) " 3 f SH23) VO Vinnt^ G bb a 20CC 53 specifics fuel costs o These curves are for engine conditions of full load and variable ‘speed a The plotted data are based on. actual fuel costs and are presented oh a brake horsepower '.basis o The curves indicate that, as a motor fuel; natural gas w ill have a fuel cost of approximately 15 per cent of

that of the liquid fuels tested* • I’or operation above 1000 revolutions per minute hP-G-as is next after natural gas in economy of fuel costs0 LP=Gas fuel costs w ill run about 90 per dent of that for gasoline :and kerosene» Gasoline and kerosene are about even in fuel costs per'brake horsepower-hour of energy produced® It must be borne in mind that the data herein presented are based ©m actual prices, prevailing in the Southern. Arizona area at ; ' this'; writingo. v :r i

Figure 23 gives a comparison of the fuel costs of

gasolinea kerosenes, IP-Gas 9 and natural gas under engine . ; . 'operating conditions of constant speed {1550 revolutions

per minute) and variable load® . Eatural gas is the out­

standing choice with specific fuel costs averaging about r 25 per cent of the costs of the liquid fuels6 , Kerosene gives a slightly lower specific fuel cost than either hP-Gas or gasoline under part-throttle constant-speed

conditions ®As shown for the full-throttle condition in Fig­

ure 22sthis does not hold true^ but under partrthrottle opera­ tion kerosene at omizes better and is used more efficiently®

. Although more fuel is used 'in producing engine power with Cents per Brake Horsepower Hour c n variabl oad a lo le b a i r a v and u.o ih engi e in g n e with, fue.Lo t n e r e f f i d r u o f r o f PCFC JL OT a iuJ HOiV^FOW,11 niVuTJ va COST FJBL SPECIFIC o p e r a tin g a t o o n e te n t "pood o f 1550 rpm rpm 1550 f o "pood t n te e n o o t a g tin a r e p o 5 Hii er v o i Hoi : r ? O a x - Ifat Gas l a r tu a f I -- □ - — Kero-iofi-.i — Kero-iofi-.i - — t -'. S r Q u P-C

00 z $ s -. -. s $ z j "ii' O 'l i i " * ^S __ 0 zo 55 " kerdseiie as eoiEpar ed to . gas oline and. LP-Gas 9 the higher specifie gravity and lover cost per gallon combine to give kerosene a small favorable margin in specific fuel cost« Gasoline e,nd LP-Gas give very nearly the same specific fuel costs for constant-speed$, part-throttle operatiotio CHAPTER V II

--. ' : COHCICSIOHS ' ' ' : . . . v - The f ollowing conclusi ons are drawn ■ f rom the experi" mental work arid analysis conducted for this .thesis a Based on fme! costsnatural gas is by far the first ' ehoiee for fuel for spark»fired engines in stationary installationso Some •loss of maximum power occurs when gasoline -is supplanted by natural gas9> but this earn be : largely overeome by alterations to the engine«, other farorable aspects of natural gas as "a fuel are high ■ anti-knock qualities9 no storage problem, and reduced maintenance and byefhaul costs» : ■ h : ■ ■■ / ;• 'In the majority of applications kerosene is no longer a competitive fuel for spark-fired ihternal com­ bustion engines in stationary or mobile use« Because of its poor performanee charaeterlstics in spark-ignition unitsg kerosene must/haye a substantial price adyantage to be eohSidered for use0 At the present: time in' most areas kerosene does hot have a favorable price advantage ■ and hence9 it is cons idered not as desirable as gasoline for motor fuel 0 i The choice between using gasoline or BB-tias for fuel is rather complex^ : Bor IB-Gas to be considered9 i t s cost - per gallon must be -less than that of .gasolineo Bien IP-Gas : ^ 'V ; ;S8;:- : may "be purchased eheaper -than gaso3.ine9 .an analysis of each - application is advisable in order to choose the most desir^

able f del a By using an engine designed to operate with •

BP-dasf the relative merits of this fuel, are enhaneeds;;:

partieularly in regard to maximum power o u t p u t o /

The updraft rake manifold prodticed a slight increase in power over standard equipment manifolds,; but the power distribution between cylinders ^nd the specific fuel eon= . sipBption . were poorer o' Under the e 1 rcmastan ces a change from the e on vent i onsQ.: style updraf t manifold to .the updraft rake type does hot: seem warrantedo . • For the type of engine tested, with gasoline for fuels, the combination manifold would -serve best, where fuel economy• is paramount and some reduction of maximum power can be tol-

eratedo The fuel -distribution of this manifold was the best

of the manifolds tested, but it still,le ft much to be desired„ Further research is needed in order to improve, this important fact or 0 ; ‘ : ; bhen-BF-Gas or natural gas Is used for fuelindica- tions are that a streamlined flow manifoId with no mimture heating would be advisable o t

:• The experimental ;data -obtained for this thesis show -

that the various fuels and -intake manifolds have a marked

effect on the pewef and economy of an Industrial engine 0. The results ahd analysis- presented'Should prove of value ; 1 \::':; . -:: ' . " : : v:- _;- -: : - «.»i to owners and,designers'of indmstrial engines in seleoting a fuel and intake manifold that w ill give optimum engine p e rfo ria a n e e » . ; .:--:v - -v•v'-.i:-

0"berts Bdward- g Imteria&l Combust ion Engines, Analysis v : and P ractice» •■Seeond’ ^Bdiiilpav'; Sei'antdBg-: /.' y; . : , ■; International Textbook Company9 19509 596 pp0 ■

L iehtys S ester C«■ 9 ■ Internal Combustion jSmgimeso Sixth : : editiono Hew York and Londong MeGraw=Hill Book i :€on$panysv:inc s 1 9 5 2 s' \ ■■ i ' V; ;V-'; '• - 'Vl' : ...... Shoopp B haries Bog and ©eoige:li:o Tuye $ Meehan ieal Engineering Practioe% a Lahoratory Reference Texto , Eourth editiono Bew" york? Torontos and Bondon % ,, . McGraw-Hill Book Company 9 Inc ® 9,19490 513 pp ® 'T 4 y l6 r> \'0 i''.!fayo■tte'■^;^.and Edward So T a y lo r s The i n t e r n a l • Combus tion Engine 0 E irst edition» Scranton § International Textbook Company9 1938o 3SS pp 0

: : . GQVEREMSBT BEBLICATIOBS ' ^

.. C ivil Aeronautics Administra/tlon'g U = So Department of : Commereeo 0» A®. Ao T e e h n ie a l Mammal BOo lOVj, A ircraft Powerplant Handbooko: . Washington % ' Cog - UoSo Government Printing O fficeg 1949» ' 359 pp0

p e h i o b i g a l : a r t i c e e s . 'i.

Tolhert j John i or "PPG as Motor Euel 9« The Plying Red . ; . Horseg 17 g 9-llj, Bovemher=December9 1951 o / . .

Eraneiseos, l)ons "This is the Story of Butane, " Hot ■ Hod Magazine^ 5 g20=S7.9 March, 1953o : - ■ ■ .

- : ; : : ■ - msTmcTioH mwAPS ■; -

PP-Gas Equipment» Operator’s Instruct!on Manual <, ' firs t edition® Jo lo' Case Co0 9 Racine9 Wisconsin0 12 pp0

Case Engine. tTnit Model "SE" s Ope rat or6 s Instruction Manual • p ?jf* P i Case Coo 9. Racine, Wisconsin0 Undated6 , ' ■" ■ UZPUBMSBBD MAMSGRIPTS

# ay s. Ted'd' 11 The Effects of Manifold- Design Changes on Charge D istribution and Engine Performance o'*; ■rv llnpublished Masteres Thesisg The University of Arizonas fuesong 1960=x 66 ppo ; /% M aynard 9 Samuel E.® 9 "Power Distribution of a Gasoline ' Engineo"/ Unpublished Master5s Thesiss The University of Arizpna 5 Tucson, 19510 70.ppo