ie Petre reentensea rahe nt a a be oe hha ae Ts coterie rer. ” Beet S Leal ota PLACE IN RETURN BOX to remove this checkout from your record. TO AVOID FINES return on or before date due. MAY BE RECALLED with earlier due date if requested. DATE DUE DATE DUE DATE DUE 6/01 c/CIRC/DateDue.p65-p. 15 ee ee or tee ee ee | a “, ‘ieee ah THESIS This thesis was contributed by Mr. S. L. Hall under the date indicated by the department stamp, to replace the original which was destroyed in the fire of March 5, 1916. SUMNER L. HALL. IS E12. e __ ye gee emanating ST, pos an Ke I: (i oF ‘7D 1 bro. a | eee, , Pe PL Lglt. DEPARTI" | : CiViL EC": MHA i>" VERSTY tise. antl THESIS ~-0000$0000-~ EFFICIENCY OF A GAS ENGINE AS DETERMINED by FUEL MIXTURE AND COMPRESSION -~~00$00-- / ” R. d. wdba A. Be. Shuart —— ee, S. L. Hall --oof00-- MICHIGAY STATE COLLEGE Spring Term -~00/1912/00- THESIS 137 b17 THS (eon! 0 Hanps OFF. Dy ea D0 964816 ak en ee ee. P ey" . ean. ‘ Sa | ——— = = | SECTION OF IGNITER PLUG 2 ENGINE SECTIONAL DRAWING OF NO. SSS SSS SSS SS SES SS Yl HIM et leeeeeee } WATER COOLED EXHAUST VALVE SECTION by Goverrer Weghle Goveraor Weigh! I] Cater 1s led yo er down $ Faitlary Tersve. nee eet ag Pe oO nn eee af GOVERNOR END SECTION GAS at EQUIPPED WITH BOTH PRODUCER AND NATURAL 2 ENGINE NO. OBJECT The cbject of this thesis is to determine the fuel mixture and degree of compression at which the Elyria Gas Engine operates the most economically and efficiently, as determined by Thermal and Mechanical means. DISCUSSION Comparatively little has been known of the exact relationship between fuel mixture and degree of compression as affecting the efficiency and economy of the modern gas engine. With the laiter coming into prominence as a compact reliable and accessible power unit, the importance of the object of a test of this kind cannot be exaggerated. Nearly all test reports upon this subject have been to amore or less degree inaccurate. due mainly to the difficulty of a suitable means of measuring the amount of air, used for combustion. The apparatus used in this thesis was a system of low pressure orifices, the exact details to be explained later. Th s method is extremely accurate for difference ofr pressure under 5" of water as is the case in our use of it. A Ventrui Meter was at first intended to be used, but on account of the fact that the pressure ratios change with each load and condition of operation,.and that it would have to be calibrated with a low pressure orifice anyway, this method was abandoned. The effect of the incurred resistance to the air of the addition of the extra piping was not noticable in the suction cards or in the ability of the engine to carry the loads and therefore not taken into account. Due to the lack of time to cover sufficient ground, the anple of ignition was not changed durins the tests and wes set at approximately the lead for ordinary operation. It was set at 15° lead. No doubt this is not the most ef- ficient angle under all conditions of compression,, but we lacked time to investigate: further. In order to keep down the heat losses as much as possible the cooling water was maintained as near 180° as was permissable by the engines conditions at the beginning of the test, lubricating difficulties kept the cooling water as low as 140°. No attempt was made to determine the heat distribution. As long as the heat losses ara kert as low as possible this does not effect the efficiency of the engine and the latter was the factor upon which we kasec our comparisons of efficiency of mixture and com- pression. After the beginning of each test, under its conditions of mixture and compression, the largest load was determined, by experiment that the engine would carry safely. This divided up into five increments to be successively applied, in order to get a sufficient number of points to plot curves The loadwas kept constant thruout the different tests by individual attention. All tests were run for 30 minutes with 10 minute intervals between tests to obtain average operating con Giticrs. Readings on the gas meter, low pressure orifices, pressure of gas and R. P. M. were taken every five minutes. Indicator cards were taken every 10 minutes with a com pression card taken at the end of the test. The latter was taken by cutting out the spark at the time of taking the card, on the c Linder under consideration. This was not dcne during the test as it would cut out a number of ex plosions and the fly wheel inertia would be decreased. Samples cf gas were pumped from the meter into a 12" x 30" tank fitted with gauge and needle valve. In order to drive out all air the tank was first filled with water and there displaced with gas. Samples were::pumped into the tank from several tests and teste@ when convenient. The samples were: for calorimetry and ultimate analysis of the gas. The analysis was meade twice during the test and the calorimeter. test run once. The exact details of this test will be given later. The amount of compression was changed by lengthening out the ccnnecting rod by putting in shims, thus chang -ng the volume of the clearance: space. The amount of change made in-clearance volume was determined by measuring the projection of the front end piston from the finished end of the cylinder when the engine was on dead center as determined bly a tramel bar. Before running any tests all thermometers used were calitrated with a standard and ccrrection curves plotted for use with each one. Likewise the scales were tested and found to be correct. The tare of the brake was determined by mounting the frame on a pulley balanced and mounted on knife edges and measured by the weicht of the free end on a pan of scales. GAS ANALYSIS In order to check the amount of air used by the engine as measured by the low pressure orifices it wes thought advisable to make chemical analysis of the gas before it entered and after it left the engine. By determining the percentage of combustible constitutents in the gas and the amount cf air required for combustion, with the excess of oxygen going thru the engine, as measured in the exhaust Fes, we could compute the amount of air used. The apparatus used was of the Hempel type on account cf its simplicity and accuracy in the hands of inexperienced men. In this process the différent constitutents are absorbed by some special reagent. The gases to be determined were CO,, Olifinis, 0, CO, H, and CHg. The reagents for the same were KOH, H2S207, Pyrogallic acid and CueCls, respectively. H was taken out by the copper oxide method, while CH4 was determined by explosion. The method was as follows; 100 ce cof the gas was collectec in a burette tube. The burette tube wes etta@hed to the KOH pipette by means of capillary tube in order to keer the amount of air admitted as small es possible. The gas wes passed over the KOH until the reading on the burette wes constant, showing that all the COp had been taken out. The diminution in volume read and the process repeated over disulphuric acid. Before using the pyrogallic pipette the fumes of the former acid had to be taken out ty means of KOH. After the precess had been re- peated over the pyrogaliic cuprus chloride and the hot coprer, 10 ce of the residue was taken and placed in the explosion bulb with 70 cc of air and burned. The following reaction took place: CHg +'40 = COp + 2H,0 The diminuticn in volume due to the 2Hp0 1s so small as to be negligible end we can measure the amount of CHy in the 10 cc by measuring the CO2 by passing over KOH. Now by determining the amount of CH4 in 100 cc from the proportion in 10 ce we have the exact percentage of the constitutents Since we started with 100 cc. Sample analysis. Before KOH 100 cc After n 97.55 cc COs 2.45 ce Before HoS007 97.55 co: After ® 91.1 ce Olifinis 6.45 cc: Before Pyrogallic acid 91.1 ce After " " __ 88.65 ce O 2.45 ce Before cuprus chlorice 88.85 cc After " " 74.15 ce CO 14.5 Before hot copper 74.15 ce After * " 42.15 cc H S26 cc Amount of COQp after explosion of 10 cc residue = 4.3 100 = (2.45 +:6.45 + 2.45 + 14.5 + 32) = 47.865 47.65 x 4.3 = 21.8 ce CHg present. 10 In collecting exhaust gas samples a pipe was led from the exhaust to a gasometer where the gas wes drawn in by the weirpht of the water. Analysis cf the exhaust gas was made during each test for each different load. The determination of the amount of air from these analysis and also the heating ,alue will be shown in a sample calculation of the thesis data. The chemical constants of heating value of each gas and 1Jts amount of eir required for combusticn were taken from the Modern Gas Engine and Gas Producer, By A. M. Levin and are given below. Air required for combustion per cus; ft. gas. H £2e4 cu. ft. CH4 9.61 " Col, 14.3 =" Cele 36. " CO Led " Heating velue per cu. ft. gas. H 275 B. T. Ue CH4 910 = CoHy 1512 =o Cele 3560 " CO 324 n The amount of air required for combustion of l cu. ft. of gas is found by multiplying the amount of air necessary to burn cne cu. ft. of each constitutent by its percentage in the gas and tekineg the total. The heating value is likewise found by multiplying the heating value of one cu. ft. of each constitutent by its percentage in the gas. All results are worked out for standard conditions of 62° F and 30" of mercury and the heating values ere given as the low heating values. CALORIMETRY The arvaratus used for determining the heating value of the gas was the one most cenerally used, namely Junkers Calorimeter which is shown in one of the cuts. In connection with the apparatus there is used a gas meter and pressure régulator. The flow cf the gas is from the source of suryly thru the gas meter, thru tne pressure regulator and thru the burner. The temperature of the cooling water is measured, by thermometers placed in the pockets vcrovided at the inlet and discharce of the arparatus. The amount of cooling water can be regulated by means of graduated valve, thus regulating the existing temperature difference of the cooling water, which should be about 15° to 200 C. A thermometer is vlaced et the exhaust gus exit and this should be maintained at the room temperature in order not to lose any heat from the apparatus. The condensation which will result from the combustion of H is drained at the bottom into a graduated beaker. The gas meter ig fitted with apparatus to measure existing temperature and pressure in order to be.able to reduce the meter reading in liters to standard conditions of 62° F and 30" Hg. Preliminary to the test the apparatus must be in Operation for some tire, until the condensation is flowing at a normel rate, and the temperature difference 1s constant. The test mav now be started by reading the meter and shifting cooling water end condensation to graduated beakers and observing the temperatures. The test 'can be run for any ienpth of time taking readiness frequently in order to get averace conditions. The measuring vessels used with this apparatus are graduated in liters and the thermometers in centigrade. The result; the weight of cooling water in kilograms times the increase in temperature in centigrade will therefore be expressed in calories which are equivalent to 3.965 8. T. U. If V ig the volume of gas consumed in cu. ft. reduced to standerd conditions at 62° F and 30" Hg. W the weight of cooling water in kilograms. to centigrede, the mean discharge temperature of the cooling water than the calorific power of the gas par cubic foot will be. H = 3.968 W(to —- tj) for its high value. To obtain the low value we have to correct for the con- Gensation in the following manner. If V is the volume of the gas used as above, C the amount of condensation im cubic centimeters then h =-2.881 x C V and H- h= HH" low calorific value. LO MEASURILG TIE GAS The amount of gus pessing into the engine was measured by a gas méter accurate within 2%. Pressure and temperature were both measured on the inlet and outlet side of the meter. These reedinrs were necessary in order to obtain the amount of gas used under standard conditions of 62° F and 30" Hg. if P) = Pressure of standerd pas (30" He.) Vi = Volume of standard gas. Tj = Absolute temperature of standard gas (621.29 F) P = Pressure of gas under meter conditions. V = Volume of gas under meter conditions. T = Absolute temperature of gss under meter conditions. Then PV, =_PV Vl. @ PVT] Tl T TP, Ty = 521.2 = 17.8378 Pi SO Vi = 12373 PV “7 11 EPFICIENCY AND COMPRESSION Besice playing an important part in gas engine design with reference to piston speed and weight of reciprocating parts, compressicn is one of the fundamental factions of efficiency. The equation of the theoretical efficiency of the sas enrine cycle is E=zi] =-(V -—1l ty i = |] = pind Where Vg = total volume of cylinder Vp = volume of compression space. r= the ratio of Vg to Vp (ratio of compression) NX = the ratio between the specific heat of the gas at constant pressure and that at constant volume and has the average value in gas engine practice of 1.35. Ace shown in the formula the theoretical efficiency increases with the intensity with which the charge is compressed before ignition. H’wever, there is a limit to this efficiency due to the fact cf pre-ignition of some fuels, under high compression. Lucke of Columbia University makes a statement that the amount of compression is limited by the amount of hydrogen present in the gas and states that. One atmosphere must be deducted from the compression for every 5% of hydrogen present. Thus the thermal efficiency of the heat transformation is first dependent on the compression that can be allowed, but it is also determined by the amount of heat that passes 12 to the cooling water. Again the thermal efficiency will vary mathematicall;, dependent upon whether the results were derived from output taken as I. H. P. or B. H. P. and the input derived from high or low heating value of the gas. [In working up all our results we used B. H. P. for output and the low heating value as the input. The use of thermal efficiency in referring to gas engine test is made more distinct ty referring to economy. By economy is meant the expenditure-in heat units that is necessary in order to get the necessary transformation, under a certain efficiency, to do the work in the cylinder. Thus (1) I. H. P. is equal to 2.545 heat units per hour and if the thermal efficiency of transformation is 24%, 2545 or 10,600 B. T. U. would need to be expanded to do I. H. P, The latter is the economy, the thermal efficiency being determined from the I. H. P. MEASUREMENT OF AIR USED FOR COMBUSTION The apparatus we used to measure the air, consisted of a steel tank, two manometers with tubes tc connect, two 2-in orifices with conneoting pipes, thermometers and ripe lead- ing to intake valve of engine. (See blue print on: page. ) The 3" pipe leading from the tank to the engine was made as short as possible to do away with friction of the air rassing thru it. This pipe projected into the middie cf the tank in order to avoid the eddy currents and so that about the same amount of air would be supplied by each of the two orifices, thus doing away with excessive suction in this case, on either orifice. The suction was always less than 5S" of water to facilitate the use of the correct constant. The tank was cylinderical in shape being 30" in diameter and 40" hieh,.and was used as a receiver for the aic to keep the cressu:e nearly constant. This made it much easier to Obtain correct readings on the manometers. The orifices were two in number and fastened to the ends of two 3" pipes which were screwed into the tank about 12" apart. These pipes were made 16" long to get rid of all eddy currents and yet not long enough to cause undue friction losses in the pipes. These orifices were of standard thickness (.057") being plates with a 2" circular orifice bored straight thru. The edges were not beveled. It has been found from experiment that with an orifice 14 of tnis size and thickness the coefficient remains practically constant with pressures up to 5" of water and does not chanee appreciably for temperatures of air between 40° and 1000 F, or for the size of receiving tank if the ratio of the area of the tank to the orifice is greater than 26 to l. We measured the degree of suction by boring holes in the pipes leading from the orifices to the tank and in- serting small brass tubes in holes thru rubber stoppers in thes3s holes. These brass tubes were placed into the pipes fur enough to est an averave rending on the manometers. Small rubber tubes lead from these brass tubes to the manometers which were of the suction type and read in hundredths of an inch of water. The temperature of the air was taken by a thermometer hung infront of the two orifices to pet an average tempera— Ture. Thus by taking the temperature of the entering air and tne pressure in inches of water we may vy the formula W = .6209 Cd2 VI. + T find the weieht of air entering the engine in pounds per second. In this cage the constant (C) is 6, d =-2", 1 = inches of water, T = absolute temperature of entering air. This method of measuring air was taken from R. J. Durley's discussion: in the Transactions of the A. S. M. E. Vol..27, 1906. ve a secon acualaet tai tie tM } e auibu 7 Of ayojul Te pe are ae Pe eee ee ee Aaa ‘ i i 2" SalIfis4o Z nays OF X,0O£ ens JR ECU A TATE TLDS I A Pee 7 , a Ld CONCLUSIONS The test was run under mixtures of 5.% to 10 cu. ft. of air per 1 cu. ft. of gas and under compression of 105 to 190/ per sq. in. The limit was reached under which the largest load that could be carried under a mixture of ll to le. Wo tests were run of Light loads as it was not deemed profitable if the largest load could not be carried. The limit of test was also reached at 190f per sq. in. of compression. At this point preignition was established to such an extent es was apt to damage the engine and the test was stopped. However, preignition was never found on the indicator card or on the comrcression card when the spark was cut out. The only evidence of preignition was the pounding of the engine. This pound- inz could probably be done away with by giving the spark less angle of advance, however, this was not done. By using the same loads under the several tests we were able to determine the effect of f.11l mixture on B. H. P., Ie He Pw. and mechanical efficiency under different compressions, as can be seen from the curves plotted; they remain nearly constant. Thus all the change thet was made by the testwas thrown into the thermal efficiency and all conclusions were drawn from the latter. The exhaust gas analysis was discarded after the first: compression test was run as the two methods of measuring the air checked, 16 From this fact we feel sure that our method of measuring alr was extremely accurate and can be vecomended for any such work as it is far less comclicated to work up than is the chemical analysis. From the results of the tests the most noticable changes were made by varying the fuel mixture, all of which would glve about the same mechanical efficiency. From the curves om page the mixture that giva the maximum thermal efficiency was a proportion of 10.5 volumes of air to 1 volume of gas. The curve would probably drop if continued, on account of the fact that a ratio of 10.5 was the weakest mixture that would maintain the same conditions of load and mechanical efficiency. These curves also show the effect of changing the compression. This 1s also shown on page - A compression of about 150% to 160% gave the ereatest thermal efficiency and also the greatest economy as shown by the tabulations. The corresponding ratio of compression ran from 6 to 8.5. A higher compression than stated would not be advisable on account of the falling off in economy of % from a ratio of 8 to 7.5. This is somewhat contrary to what might be expected from an inspection of the theoretical efficiency curve, but is probably due to the excessive loss of heat given to the cooling water at the time of preignition. From the curves showing the effect of com- pression and from results of other tests, it would be L7 reasonable to assume that if preignition could be srevented a hicher economy could be reached. This preignition could be prevented by the udmission of a@ spray of water in with the incoming charge, which would tend to cool off the cylinder. Regarding the cause of prelgnition, we cannot say, but from Ovher experiments made by authorities who haves layed it to the amount of hydrogen in the gas, we reached ea great deal higher comcression per volume of hydrogen present than did either C. E. Lucke of Columbia University in his "Gas Fngine Design" or H. E. Wimperis in his "Internal Com- bustion engine". Again it might be caused by carbon particles in the hich heat of ignition and compression. Acain a hieher efficiency and economy could have been reached by changing the angle of ignition. Cerds No. 10, 11 and 12 were taven of the 654 load under ths respective tests and sh-w a slow burning mixture thet could be remedied by increasing the angle of ignition. For the other tests the anple of ipnition was about right. One peculiar feature was noticed in the experiment and, thet was the ratio of air to gas was not constant thruout a certain mixture under different loads. As can be seen from some of the curves the ratio curve is not always a straight line. This probably is due to some defect in the pressure regulator of the gas main. The conditions under which the enpine pave the best 18 results are: ratio of air to gas = 10; compression = L50¢ per sq. in; cu. ft. of gas per B. He. Pe per hour = 21; mechanical efficiency =-80%; thermal efficiency = 234; load 170f and developes 40 I. H. P. The exponent (n) as used in the formula for the theoretical efficiency of the Otto gas engine cyclée was determined from the compression cards by means of the following formulas Fe tay Po Vi P, = initial pressure Vz = total cylinder volume Po = pressure at any point of curve Vo = volume corresponding to pressure Po. n= ratio of specific heat of the ges at constant pressure and at constant volume. From compression No. 1 rear cylinder. Py = 14.7 - 10 = 4.7 Po = 14.7 + 38 = 52.7 Ve = 141 cu. in. = cleurance svace. Vi =- 141 + 603.18 = 744.8 = total volume of cylinder. 4.7 = (141)2 62.7 744.8) Log 4.7 — log 52.7 = n(log 141 - log 744.18) ~ 672008 2.149219 -1.721811 _ 2.871845 © 250287-2 0277665-1 (n). n = 1.049713 0722455 19 = 1.46 Cards Nos. 1, 3, 4, and 5 give the following value of No. ao OO 1.45 1.345 1.25 1.49 1.386 = average. 5.28 F Cy/ EY AL heh Ad Ale Da Agel niage: S a3 I Sent > re YW Pe ES abe OFS SS y) is) Y eae, iS BE Wai pay ‘alg 4 é e 3 8 E ie . © = 5 oe |. L a ; Se ee Ck = bat ea By 3 yy Bie fe So Sea ye a ee ee 165 30 3/2 iA ak 29.25| 2.84 ae 130 B=} a eS 5.15 te gS 32Zl a cya RT ao) oe ree) 326 Bo Foe g Ke M 4 re Vy CTY ae 38 (29.24 | 4.00 vA Test No.2. Comp Nol. (11. N02. A) Zo 308 /22 hres 28.84) 2.44 72 ey Cae ee rd re Tle eA Tz cer yes Ze) ce ee 65 324 Ae) FF 3.6 Veo £2) sa 5S 48 28. rr} a Vee Test No.3. Comp. Wol Mix, No3. ED ey ear TT, Jos | 29 | 2.65 | 70 x4 BIS | 98.5 89.5 |) - w 2 70 rye Ee ee eee 4 23.98 | 3.5 val ei Ty: 67 Pye eae ee Et B25 Pee ET) 28.98 | 3.87 ves Test No. 4. Comp.Wo. Mix No. 4. ez ET) Sil ae jos [28.94 | 29 | 65 135 ar 99 PY; ea iP 7 52/ ga.5| 7/ |28.93 | 5.45 | 66 65 cre Ve) E+E x6 cae eee 3o 3527 $2 44 28.94 | 3.38 oR Test No.5. Comp. No.l. Mix No.5. res 7 Ye 7 Ye 2B 135 sie | 4085 | 98 T ere. 100 ETT Ey eee, 29.04| 3.7 ay ey B23 PEe ee Ene Zo Fes cr) CYR eee ees 63 lawn arod aa RC aoe ao, a, i Eva 8 JEN Pied A LA € e 2 | Pressure eee oS Ma PRAT ae ies a SJ §& aS 7) re aan be te Fae e/a le aE 1% Le 7 fe ah ie Ee) et ed Ss ~ S EI So ie oy eA ae A Oe ee 7 Mane tba na bse nd ey; ; rr ; as /4i9 1 Mix. No.3. 7 ee / 55 VaR eae) a} aS) r Test No.4 Comp.No.! ie ead 2 | FOF 1.902 |, 75.4 ea i: 6 oa orks L Se I Nol. Mix. No.5, . Ee Seo s a Cenk ia (Ze-EI 67.7 oO WATT EO a aa A ee a \) an -< $iS on = : pL eas Se ae fering) aa " ae ae 1 ‘> Core . P EY : PBs *3 - = c a) . p & Le acaeas m3 7 7 me) > } 1) "(Fa A aa A Ave 9 | 347 | 79.9 | 78.0 E 5.5 | 77. Xe} "a . aS /6./ 0. Bea pate A ; eis oO | /F. i f : — Test No. 4. Nal. Mix. No.4. yf eee Se oS Berita ee 19.3 : af oe ees oe A - x 0.7 vay Test No.5.Comp.No.| Mix.No.5. ~ Rms ee AS aero 30.8 | 72.9 | 22.2 = a Aige y fe oO. 8 SLES a} | 20:52 | /26 : . 4. 76 iF 36 ALL, of BO eee R.Cyl. aes a meredi ore} Load a mpre et geste aa ye a acco | Ba ae ee Ome wKy Pressure war el val é aye Te . TEE ee No.l 170 B12 Wet Aa ae ra Tiel ie 72 ee LIS 70.6 ry mR yee era 3.28 | 72.06 Ce Lz rz3 zs Xe are) ‘S Ci Oe 326 | GF | 50 |28.67 | 3.62 | 73.87 Cee ne caer ee TA eer ee : i7e | go. | 312 [ 732 | 120 | 29,08 | 2.85 | 69./4 ire | bee Sat 244 a8 VA EEY vay ae 72.6 65 324 | 73./ Ee : Tra 73.2 ae eee /70 SIF = ee] (35 Re rai i mele) a ee (oy or 65 oe 727) Jo ore ee IN} ee te a A a G2. 4- By eay eet 68.5 TX Evy 72.413 65 eet Ve ry re Jo , 326 ‘ F roe 3.65 72.7 Test No./0 Conmp.No.2. Mix Nos | 735 | 30 | 3/0 | (44 | 726 |29./3 | 3.05| 576 /00 a) aan ae 35.28 ee oe a co ee 3S 326 6S oy Ratio of Compression R.Cyl. 6.0F F.Cyl. 5.65 Gas Alar ~ S o < essure 3 Ney = au a Pye a ai fl he ieee ce ae x as ee Bee A A A ae et SS eT OR ee ee ee a OY a eae AA 3.0 SS "3 SG = 2? [Wot at a SES S Test No.6 Comp.No2. in Pea ae /70 | 405 | 366 693 | 82 | 78 xy Pee 135 | 338 | 322 562 | 699 | 88.5 | 2376 ae} 279 265.5 | .425 BeLI B6.85| 2093 at 224 | 2/3 rie 438 | B75 | 1805 30 169 ye ey eee es) 84 | 1453 eRe ae Bt Ue: 2 3 NT ea Pit 8: or es re Sire ie ee Bee. bioar 26/8 | S.l (35 | 377 | 362 aac 7g | 2367 | 7 me) 4. | ..47. | 78.54 | 2035 65 227 CA ies _.28 344 | 73.85 | 1750 | 30 Tn ee ee ee ce ace oe Ree Ye a ee 770. | 378 | 366 | .676| .e2 | 69.4 | 2687| 1 735 | 334 | 3235 | .$8/ | .677 | 77/8| 2432 Xmen 2 ee cr ee EY a aed Fd 228 | 216 | .3s a} PY Wee 30 ie} ke Ge aa ee ae dS ae Test No.9 Comp. No. 3 (11x. No: 4. (70 | 370 | 356| 758 we ee A See Ed tes Ye cd ee ee a Ty: 28/ xr 47 PTA) ee ee er 6s | 227 | 2/4 Pye te eee Ce 30 ial ae .20/ | .268 | G2. | 75/7 Test No./0. Cortp.Wo.353 Mix No.5 iz | - eae eee ET We a eee CA ae ee ae eee el 65 2/0 | 202 Pry a el ee 35 174 | /68 | ,288| .565| 79.) | 1951 Ueetmy Coo R.Gyl. 6.04. ENA 5.65. Q = ke PRES Qrkae 1s Sin . Re -|eh > oO] ee ogee Ws ee ww Py S A E a Ss =e Pe oe aes oe Pe ae Sie Bere of OME bo ihe Regret ic at Sere ih See SM SG ae See MQ is Cat Test No.6. Comp.Wo.2. /Tix.No./. aT 6.95 | 2426 | 4/.8 | 34.8 | 76.1 | 20.6 Ke 7.37 | 25.0 | 36.9 | 261 | 69.6 | s8.8 /00 71.9 27.6 | 29.2 | 19,25| 66.0 | /7,.25 ey 8.4. | 33.8 | 20.3 | 42.6 | 620 | 1409 30 | 9.06 | 5647 | /4.3 6.86 | 41.0 8.7 Test V0.7. Gomp. No.8. Mix.No.2. Lewy) 2702! 41.4 | 31.6 | 769 | 12.5 135 | 6.54 | 28.02 | 36.79 | 25.7 | 7,9 | 16.8 /00 7.9 | 28.9 | 2766 | /9.3 | 69.8 | 6.4 65 | 8.0 | 343 | 20.6/:| 1265} 6.75 | /3.8 30 | 8.3 | 546 | /3.28| 59 | 944 | 8.75 Test Vo.8.Comp. No.2. Mix. No.3. KT 7.394 | 2295| 39.05) 3/.92! 8/.15 | 20.7 (35 "| 7.62 | 26/6 | 33.3 | 25.68 | 77./ Sa /00 -| 8.56 |273 | 27.58 | 19.26! 69.9 | /7.3 65 | 8.69 | 343 | 2086/| 12.6 | Gos | 7/3. 30 A) 56.4 | /468 | 5.86| 40.0 j. 6.55 Test No.9.Gomp Noe. Mix. No. oa RE 7.8 | 22.21 | 39.4] | 31475 | 80.6 | 21.2 KEY 7.8 | 245 | 92/2 | 25.6 | 79.7 | 13.4 /00 8/3. | 27.7 | 26.e5 | /9.2 |-9Z.0 eA Ce 33.9 | 20.53 | 12.63} 61.6 | /4.0 30 | 9.35 | 59.2 | 4438 | 5.867| 408 | 8.75 Test Vo./0.Gomp LE /Tix.No.9. Ee) ton /0.8 23.7 32.67 | 25.12 | 76.9 Pa TT oe ee ee eee eee eee ese een ee 32.0 | 2054 | 126 | 644 | 485 CT eee a 490 | /4.77 | 685 | 46.4 | 9.7 Fratio of Com 1-16 A , (Oat aK Wa lille ressure LAE 3.3 Oe bie cor) * : Pe [4] 2.73 Ratro of Compre ssio. : Cyl 7.4 Pi (nV) a ALLL | ; waa) Pest NoJl2.Com , S ara AUS AO IEd ~ OMPRE 8S 10" NUM BER. s Bp es hy Pe cpt ere Me ia ae om SE: all dol fale Cee eat “ bea | 1a | re + wien ag mere eae aa [40 a cee EE 529 re < (ones TE QUIRED RR SBN) 24 er ee eo M ato cee ’ ns =) wv a, ore ee & he oe oie < = 7 r om 5 reo aera dot ad fe ys F - A 2 Cg —y B = = an how oe pe ae ro bite Sk SP Bia oth Be ae We fe OS cee es —" hee Bel cz cao | é a = - Oe 9 F f ed at tas oe a ae A ‘ a a Shy WR RU Ry 0D at " int re ee, Vigr tee Comp. /. | /3.2 I "as ‘ er : 92 Xero /,0 oe ee - = } ; 9.6 mB B 12.2 | 7.6 hn 3.6 Peat S aaa 8.8 O ere (4) 10.4 oe es ols|o Be is 0 a a sah RF. Crk. ey hla ka on ae THETEM AL ee aAE THE pe ab Ce fe ~ E Ral aaa F.CcYkh sea ae TLL ren aad FOR dul 6 7.C YL. agen Av. THEO. | cae nani Fal Tae COM PTRESS/OM 1 Ma aR 7 S/N GAS ENGINE. ren ca Ne mat ada F. CYh. 5.28 OQ) 45 # as“ a) rs rem 434 12,900 oe 20.6 re ey CA 46.7 ERA Pinst Bie. me) ry ee La ~=|™ fas x mf: aT hv4 49.6 xe K | 4.9.9 13,600 /66 ™~ © S rs Curves showing the relationship of I. H. P., mechanical efficiency, thermal efficiency, ratio of air to gas and Cu. ft. of gas used per B. IH. P. with B. H. P. --0000$0000-~ ] } i SRE TEA EL ee PIR EE | “4 re ~ ' ig cl Re Oy RL eWon ey ss - yr agesees ; eeraee — | N eee 2 a alates Eee a bbb) bbb hos oh 4 1 65 os Mibeae hi i itereseas on Pan AOS Cas ae pm Ams a3) vat aaa 2 ae ee TesT No.9. THST No.t2. eae Wee exha Cee eno-- 4 test Wo. 1. FO*¥ spring: eta, rat rms FA 50% spring. At alae ap Catt aA 60" spring: APOCRNDIX ra OUTLINE OF THST Efficiency of a Gas Enpine as Determined by Fuel Mixture and Com,ression. The test will be run under different conditions of fuel mixture with different loads and different conditions of comoression. 1. The loads are to be aprlied by means of a water cooled Prony brake and applied in this order; determine the largest loud the engine will carry under operating con- ditions and divide it up into five increments, the loads to te applied successively. This will give five points on all curves plotted with loads. “@e The length of tests are to be from 50 to 40 minutes, taking readings every five minutes. 3. R@adinrs necessary. Gas meter. Temperature on both sides of the meter, the inlet side and outlet side. Pressure on corresponding sides of the meter. R. P. M. of engine. Venturi-~meter manometer rexdings. Air temperature ut venturi-meter. Barometer reading, beginnine and end of test. Loads. Time. 25 4. The ges is to be measured by a standard gas meter. Samrbes are to be pumped into a tank during the test and the calorific calue determined at the end of each test if possible. An ultimate analysis is to be run at the same time in order to check all work. 5. The air is to be measured by means of a suitable low pressure orifice arranged with a by-pass for starting. 6. The compression is chanced by putting in or taking out Shims in the connecting rod. The amount of compression is measured by use of an indicator and reducing motion cutting out spark at the tims of taking card. 7. An ultimate analysis will be made of the exhaust gases, thus giving a check on the amount of air passing through the engine. 8. The I. H. P. is measured by means of indicator cards, taken every five minutes, and the engine constant. 9. The B. H. Pw. i8 measured bd means of brake load, which must be kept constant thruout the test, and the B. Il. P. constant. In refard to the different mixtures, the limits will be found by tra@al and work will be carried on within those limits. The outlet temperature of the cooling water should be maintained as nexur as possible at 180 degrees F. The angle of ignition is to be set at 15 deg. and is to be maintained constant thruout the test. 24 BIBLIOGRAPHY 1. The gas, Petrol and Oil Engines, By D. Clark, Member of the Institution of Mechanical Engineers. Published by John Wiley and Sons, 1909 edition. Combustion and explosion Chap. 5. Treats on the true explosive mixtures and heat of combustion. Efficiency of Gags in Fxplosive mixtures, p. 140, Oldham gas gives maximum with air to gas ratio of 12 tol. A treutment of the thermal and mechanical efficiency of the different types of gas engines le given in Chup. 9. 2. Gas Engines Design. By. C. E. Lucke of Columbla University. Published by D. Van Nostrand Co. 1905 edition. Air required for combustion,.p 25. Ratio of air to coal gas 5.06—8.38 to 1. Effect of fuel mixtures on compression, p. 33. 1 atmosphere should be deducted, from amount of compression, for each 5% of hydrogen present. City gas allows a compression of 60 to 100# per sq. in.. 5. Guldners Internal Combustion Engines. A translation by H. Diederichs of Cornell. Published by D. Van Nostrand Co., 1910 edition. Ratio of air to gas p. 554 Illuminatin:s gas 11.7 to 1, water gas 7.1 to 1. Air required for true explosive mixture p. 538.