sign in sign up
<<
Home , Dynamo

1 .LADJUS ON H 1 .IFOm . I.C.

SSIS 3ented to the Faculty of the Division of Graduate Studies Georgia Institute of Technology

In Partial Fulfillment of the Requirements for the Degree Lor of Science in Mechanical Engineering

by- Ernest Elsevier September 1950 ii

STUDY O.1 3 , .NTS

ON THE PERFC EM I.C. ENGINE

Approved: •' —-' s /n. 7 -"U

t

1

/

_^v a A n J •

Date Approved by Caairmans&^^&sf? iii

On the completion of this rork I vish to express :ay sincerest thanks to Professor H. L. Allen for his most valuable aid ana guidance. 1 should also like to thank Mr. T. D. Sangster, mechanician, for his cooperation in the construction ;ine. TABLE

Acknowledgments List of Tables List of Figures List o£ Abbreviations

Introduction Purpose Objectives Equipment Procedure Discussion Conclusion

Bibliography Appendix I Appendix II LIST 0 1LKS

I Performance Data of the Engine irk Plug Ga: .010 inches II Performance Data of the Engine Gap .020 inches III Performance Dar-a of the Engine Spark Plug Gap .030 inches IV Performance D C the Sri' ark Plug Gap ,05-C inches V Performance Data of th^ En Spark Plur Gap . 0-;<0 inches VI Performance Data of the En Spark Plug Gap .060 inches /II Results of the Performance of the Engine B.H.P. and Thermal Efficiency For Table I and Table II VIII Results of the Performance of the Anrlne B.H.P. and Thermal Efficiency For Table III and Table IV IX Results of the Performance of the Engine B.H.P. and Thermal Efficiency For Table V and Table VI vi

LIST OF FIGUBSS FIGI PAGE 1 Photograph of the Fisher Gas Analyzer 23 2 Photograph of the Control Panel, Taylor , Fairbanks Scales, and the Direct Reading Potentiometer 2k 3 Photograph of the thermocouple leads, variable , and spark advance control 25 Graph of sparking required to jump a given spark plug gap 26 5 Graph of the thermal efficiency for a given spark advance at 5 in. Hg vacuum 2? Iraph of the thermal efficiency for a given spark advance at 10 in. Hg vacuum 28 7 Graph of the thermal efficiency for a given sp a dvance at 15 in. Hg vacuum 29 8 Graph of the thermal efficiency for a given spark plug gap in. Hg vacuum 30 9 Graph of the thermal efficiency for a given spark plug gap at 10 in. Hg vacuum 31 10 Graph of the thermal efficiency for a given spark plug gap at 15 in. Hg vacuum 32 vii

TICKS

1. C02 Carbon Dioxide 2. Oxygen c 3. CO Carbon Monoxide h. KOH Potas3ium Hyd r oxid e 5. HGL Hydrochloric Acid

6. CuCl2 Cuprous Chloride 7. Hg Mercury 3. R.J •;lutions Per Minute

. B.H.P. Brake Horse Power 10. c.c. Cubic Centimeter 11. lbs. Pounds 12. in. Inches 13. min. Li mites 1

A STUDY 0

ON THE PE MANCE 3 ' . : I.C. ENGINE

INTRO1.'

Purpose

Current internal combustion are charac­ terized by their higher operating speeds and -vider speed range, higher compression ratios, higher specific out­ puts, and greater economy.

From the spark plug point of view this resolves itself into operation over wider ranges of speed pressures, and temperatures, and in leaner or less easily ignitible mixtures.

Furthermore, the addition of detonation inhibitors to the fuel, notably tetraethyl lead, has greatly in­ fluenced spark plug behavior.^ Two of the more easily met requirements of the spark plug are: the conduction of high tension current in"co the , and the furnishing of a suitable pair of elect een vhieh the voltage

1 Bychinsky, ".-.,, "Factors Affecting Functioning of Spark Plugs", S.A.E. Quarterly Transactions. Vol, 2, No. 2, 19M3, pageTH -It??. 2 can spark. These n ements are considered simple and easily met. There are many things that a spark plug must not do. It must not cause an extra hezvy load on the ig­ nition system. The gap should no": change or wear, the required sparking voltage should not vary, and it must not be located in the engine where the initial ignition is undesired. It must not run at too high a temperature, thereby causing preignition. The electrical needs of the engine are not, by any means, constant in value,fife ar e required to furnish a voltage sufficient to bhe grip of the plug. The amount of voltage required, is a function of gap size.2 In presenting the fol] ; thesis, the author will show that if a spark is obtained across the gap of a spark plug of .020 inch, the mixture will be ignited satisfacto­ rily and even if the spark plug gap is opened to .060 inch, it will have little or no influence on the burning after the mixture has been ignited, Objectives The objectives selected for this thesis were as follows;

1 Bychinsky, /.A., "Factors Affecting Functioning of Spark Plugs", page 160-189. 1. To redesign the whereby the spark advance would have a positive control. 2. To install a carburetor whereby the air-fuel ratio could be controlled. 3. To study the effects on the performance as spark plug gaps were opened and the distributor spark advancede k

iiNT The engine used for this thesis was a four Continental Red Seal Engine, whose was 2£ in. and whose was 3~ in. The was 6.2-1, and the S.A.E. rated horsepower was 10.0,3 The engine was connected to a Taylor Dynamometer with an automotive type univ 1 joint. The dynamometer constant was 6000. The dynamome­ ter was connected to a Fairbanks scale so the load applied to the dynamometer could be measi The fuel for the engine we• ghed on a Toledo Le. The scale c be read to one hundredth of a p ound 3 A control panel was installed which contained an manifold manometer, i . manometer, a chometer, a direct reading manifold pressure gage, and engine oil pressure gage, a , a , a bubton, and a temperature selector switch. An aircraft type tachometer generator was installed

5 Figure 3, Page 25« ^ Figure 2, Page 2k. 5 Figure 2, Page 2k. 0 Figure 2, Page 2k. on the shaft end of the Taylor Dynamometer.' The distributor which came installed on the engine was taken apart and the fly weights were locked in the closed position, a plate marked in degrees was then in­ stalled and an indicator was so set whereby the advancing or retarding of the distributor, in degrees, could be accurately controlled. This engine was not equipped with vacuum advance. Thermocouples were installed in the water jacket and in the , whereby the operating temper­ atures could be checked vith a direct reading potenti­ ometer. '

Figure 2, Page 21*. 8 Figure 2, Page 2h. 1 Figure 3, Page 2?. )CEDTJRE The degree of distributor nee desired was set on the engine and the spark plug gap was opened to its desired size. The engine tachometer was checked and cali­ brated with a strobotac. The engine iven ample time to reach its re­ quired operating temperatures, the required R.P.M. and manifold pressure were then set to their desired values. Before any data were taken, from the dynamometer, to de­ termine the horsepower, the air-fuel ratio was first de­ termined by analyzing the exhaust gas. The exhaust gas was analyzed in a Fisher Gas Analyzer, Unitized, Technical Universal Model, of the Orsat type.1 0 The procedure consists of first confining a measured (lO c.c.) quantity of *as in a graduated tube called the burrett and then passing the gas into vessels called pipettes containing different chemical solutions wherein uhe various components are successively absorbed. After the exhaust :•• s is bubbled through each pipette it is returned to the burette and the volume measured. The decrease in volume is determined and the percentage of trie particular component present in the exhaus: calculated.

Figure 1, . 23. 7 The Orsat analysis of the exhaust gases absorbs three distinct gases in the following order, CCU, 02* and CO, The CO^ was absorbed in the first pipette con­ taining a twenty-five percent solution of potassium hydroxide. The Op was absorbed in a solution of pyro- gallic acid made by dissolving fifteen grams of resubli- mated pyrogallic acid in lJO c.c. of twenty-five percent solution of the potassium hydroxide. The GO, if present in the gas, was determined by absorption in acid cuprous chloride made by saturating HCL with CuClp, and reduced with wire. A sampling bulb unit was used for the transference of the exhaust sample to the precision gas analysis assembly. The sampling bulbs were attached to each ex­ haust port on the engine. A supply of fresh chemicals was available at all times and the aspirator ABS in continuous operation dur­ ing the duration of -he run, insuring accurate results. Chemicals were replaced according to instructions given by the manufacturer. Care was taken to see that the water used in ohe burette was saturated with a salt solution to prevent absorption of the gas in the water. If, Volume of sample <=- A Volume after (COo) absorption = B Contraction (A-B) =C then % C02 * (C x 100) 7 A

and, Volume after 0? absorption *= D Contraction (B-D) s=B

then, J 0 = (E x 100) r A and, Volume after CO absorption «=F

Contraction (D-F) *=G

then, % CO sr(G x LOO) * A

and, ! N2^ CJ,f. 0-,-t J CO) The air-fuel ratio was kept constant for all the runs, After the carburetor was readjusted and the air- fuel ratio checked again, the fuel consumption was then recorded for a ten minute run and the load on the dyna­ mometer scale was recorded, Calculations isrere then made for the B.H.P. and the thermal efficiency. DISCUSSION The fuel consumption ?as the same for the same but the load and the efficiencies varied. The efficiencies were plotted against the spark plug gap opening and the degree of spark advance. Where the thermal efficiencies were plotted against the spark plug gap, it was shown that for 5 in. Hg vacuum, the optimum spark advance was 10 degrees advanced, and for 10 in. Hg vacuum, the optimum spark advance was 20 degrees advanced, and for 15 in, Hg vacuum, the optimum spark advance was 20 degrees, although the 30 degrees advanced was only .03 percent less for 15 He in. vacuum. Where the thermal efficiencies were plotted against the spark advance, it was shown that for 5 in Hg vacuum, that the maximum efficiencies were reached at a little less than 10 degrees spark advance for all the spark plug gap openings, and for 10 in. Hg vacuum, the maximum ef­ ficiencies occurred at 18 degrees spark advance, and for 15 in Hg vacuum the maximum efficiencies occurred at 20 degrees spark advance. Conclusion It has been shown that if a good spark is obtained across a gap of .020 or greater, the mixture will be

Figure 10, Page 32. ignited satisfactorily and the rap size will have little or no effect on the efficiency- 12 From the preceding statemenc it may seem that ;?e should set all spark plugs at the highest settings, but to do so would increase the sparking voltage requirement. The higher sparking voltage would decrease the amount of fouling that could be tolerated without engine miss.

2 Figure 7, Page 29. 11

TABI

Perf rmance Data of the iinrine

Run Dynamo- bpark Spark Intake Air- R.P.M. ;>nuel No. meter Plug Advance Vacuum Fuel Cons. degrees Hg,in. Ratio 10 min, Load, Gap, lbs. lbs. in.

32.50 .010 10 5 1^.9 1500 o.97 2 32.00 .010 20 5 1U.9 1500 0.98 ' 29.50 .010 30 l'+.9 1500 0.97 26.50 .010 1+0 1^.9 1500 0.97 20.80 .010 10 10 lh. 9 1500 0.76 6 21.00 .010 20 10 l*+.9 1500 0.77 7 20.30 .010 3n 10 l*+.9 1500 0.77 6 18.20 .010 l+O 10 11+.9 1500 0.76 9 8.80 .010 10 11+.9 1500 0.55 10 9.00 .010 20 15 l!+.9 1500 0.55 li 8.50 .010 30 lf; I1-, i :.. 0.56 ! 1500 12 5.00 .010 ho 1 5 l't-,9 o.^5 12

TABLE II

Performance Data he Engine

Hun Dynamo­ Spark 8 p.- rk Intake Air- R.P.M. Fuel Mo. meter Plug Advance Vacuum Fuel Cons. Load, Gap, degri Hg,in. Ratio iin. lbs. in. lbs.

13 10 5 A. 9 1500 0.99 Ik 32.80 .020 20 1V.9 1500 0.93 15 29. 10 .020 30 r: 1U.9 1500 0.98 16 26.10 .020 hO 5-' ll>.9 1500 0.98 17 2C.70 .020 10 10 1^.9 1500 0.76 18 2C.90 .020 20 10 1^.9 1500 0.76 19 2C . 2C .0-20 30 10 l^f.9 1500 0.76 20 18.00 .020 ho 10 l'f.9 1500 0.76 21 . -3C .020 10 15 1^.9 1500 0.5*+ 22 10.00 .020 15 1^.9 1500 0.5^ 23 10.00 .020 30 15 l^f.; 1500 0.5^ 2h 8 Ac .020 IfO 15 IV.9 1500 0.5h 13

LE III

Performance Data of the Engine

Run Dynamo- Spark Spark Intake Air- R.P.M. Fuel Mo. meter Lug Advance Vacuum i"*uel Cons. Load, Gap, degrees Kg,in. Ratio lr min. lbs. in. lbs. 25 3^.20 .030 10 5 l>+,9 1500 0,98 26 33.10 .030 20 lli-.9 150c 0.98 27 30,1+0 .030 30 llf.9 1500 0.98 28 26.70 .030 ho 5 l*+.9 1500 0.97 29 20,90 .030 10 10 1V.9 1500 0.77 30 20. 50 .030 10 1^.9 150c O.76 31 20.1+0 .030 30 10 1^.9 1500 0.77 32 17.60 .030 kO 10 1V,9 1500 0.76

33 9.36 rop 10 15 1^.9 1500 0.55 3^ 10.00 .030 20 15 lh.0 1500 0.5^ 35 10.00 . 30 15 1U.9 1500 0.^5 36 9.00 .03c 1+0 15 1J+.9 1500 0.56 lU

JA3LE IV

Performance Data of the Engine

Run Dynamo- 6park Spark Intake Air- R.P.M. Fuel No. meter Plug dvance Vacuum i^uel Cons, Load, Gap, degrees Hg,in, Ratio 10 min. lbs, in. lbs.

37 3^.00 . oi+o 10 !r l*+.9 1500 38 33.00 .oi+o 20 l*+.9 1500 0.97 39 30.00 . oi+o 30 lif.9 1500 0.97 kc 27.10 .oi+o hO 1^.9 1500 0.^7 1+1 20. .OhO 10 10 JA.9 150c 0.76 1+2 21AO .01+0 20 10 llf-,9 1500 0.76 -3 20.60 .oWo 30 1C XU.9 1500 0.76 M+ 16.00 .0^0 40 10 1U.9 1500 0.75 h? 9.80 .oi+o 10 15 1'+. 9 1500 0-53 >+6 lr'. !C .oi+o 15 11+.9 0.52 h7 10.00 ,ci+o 30 1V.9 1500 0.53 k8 8.50 .0*+0 VO 15 li . ) 1500 0.52 15

TABLi V

Performance Data of the Engine

Run Dynamo- Spark Spark Intake Air- R.P.M. ?uel No. meter Plug Advance Vacuum Fuel Cons. Load, Gap, degrees Hg.in. Ratio 10 min. lbs. in. lbs.

h9 33.70 .050 10 5 ltf.9 1500 0.97 50 32.50 .050 20 ' 1^.9 1500 0.97 51 30.00 .050 30 5 1^.9 1500 0.97 52 27.30 .050 IfO 1^.9 1500 0.97 §? 21.50 .050 10 10 llf.9 1500 O.76 5? 22.00 .050 20 10 1^.9 1500 0.77 55 20.70 .050 30 10 1^.9 1^00 0.76 56 17.60 .050 ko 10 1U.9 1500 0.77

57 9.20 .050 10 15 l*+.9 i5oc 0.53 5S 10.10 .050 20 15 l^.Q 1500 0.5^ 59 9.80 .050 30 15 1U.9 1500 0-5^ 60 8.70 .050 ho 15 11+.9 1500 0.55 TABLE VI

Performance Data of the Engine

Run Dynamo- Spark Spark Intake Air- R.P.M. Fuel No. meter Plug Advance Vacuum Fuel Cons. Load, lbs • Gap, degrees Hg,in. Ratio 10 min in. lbs.

61 33-70 1^.9 1500 .97 62 32.20 .060 20 1V.9 1500 0, .98 63 3C00 .060 30 lif.9 1500 0. .97 6% 27.20 .060 1+0 1500 .97 on o-\ .060 10 1500 0, ,76 65 CX m j \-' 66 22.00 .060 10 l^-.9 150O .77 67 20.80 .060 30 10 1^.9 1500 ^75 68 18. UC .060 10 1^.9 1500 0, .76 Ao 8. SO .060 10 15 llh.9 1500 0, .53 70 10.00 .060 20 15 Ik.9 1500 ,52 71 9.80 .060 30 15 m.9 1500 ,5^ 72 9.60 .060 15 11+.9 1500 0. .53 17

TABLE VII

Results of the Performance of the Engine

For Table I For Table II Spark Gap Spark Ga{) .010 in. .020 in. Run B.H.P. Thermal Run B.H.P. Thermal No. Efficiency No. Efficiency %

1 i?.-;;o 13 S.55 18.72 8.0 17.52 Ik 8.2 17.95 3 7A 16.21 15 7.5 16 A3 It 6.5 1H-.2H 16 t.5 lh.2h 5 5.2 1^.3 17 5.2 Ik. 30 £ 5.25 1V.5V 18 5.28 lh.52 7 5.1 1^.03 19 5.1 IW03 8 k.55 12.51 20 V.5 12.38 9 2.2 .1+8 21 2.3 8.87 10 2.25 67 22 2.50 9.65 11 2.1 ,10 2.5 9.65 12 1.25 h.^2 2h 2.1 8.10 TABLE VIII

Results of the ormance of the Engine

For Table III For Table IV Spark Gap Spark Gap .030 in. .Ql+0 in. Hun B.H.P. Thermal Run B.H.P. Thermal No. Efficiency % No. Efficiency

25 .55 18, .72 37 .5 18, .62 26 &\,2 8 18, .13 38 .25 18, ,06 27 ,6 16, ,61+ 3? 7, .5 16. M 28 ,68 lV.63 1+0 ,78 lV.85

29 .23 lht ,uo 1*1 y 1. 3 li+, ,60 30 .13 1^.65 •: ,1*2 11+,.9 0 31 ,1 l*+. .05 ^3 \ .15 lit, .17 32 k, ,1+0 12, .30 U1+ h,, 5 12, .38 33 ,3h 9.,0 2 1+5 .37 ,1*+ 31* 2, SO ?. 1+6 2, ,55 ,.8 3 35 .50 ..61 + 1+7 2, .5 ,61+ 36 ,25 1+8 -13 \ ,20 19

Results of the Performance of the Engine

For Table For Table VI Spark Gap Spark Gci p .050 in. .060 in. Run B.H.P. Thecal Run B.H.P. Thermal No. Efficiency I No. Efficiency ;C

1+9 8. »f 3 18.1+6 61 8 A3 18.1+6 50 8.13 17-80 62 8.05 17.60 16.1+3 51 7.5 63 7.5 16.1+0 52 lU.78 6>+ lU.85 6.75 6.83 5} 5.38 65 5.39 l*+.80 5.5 15-13 66 5.5 15.13 5h 5. IS 1^.25 67 5.2 l^f.30 55 12.50 56 V.33 11.90 68 h.58 57 2.3 8.85 69 2.2 S.hd 2 58 2.53 9^5 70 9.6h 59 9A5 71 2A'? 5 60 2.1+5 8A n2 1.25 2.18 2A0 20

Bychinsky, V.A., "Factors Affecting Functioning of Spark Plui's", S.A.E. uarterly Transactions, Vol.2, No.2, 19V8.

Fraas, Arthur P., Combustion jinr'.re;, N.Y.: McGraw-Hill, 19V8. p.197-212.

Jennings, B.H., and E.F. Obert, Internal Combustion WEngines^ . PP..: Intel nal l'extbook, 19M-9- P-3^3- Judge, Arthur .'/., *UT;omobile and Aircraft Engines» London: Sir Isaac Pitman and Sons, 193^. p.3^-35-

' s 9y, A. T. J., I n b ~: rnz.' Combus t i on Eng ine erinK , London: Blackie and Son, 194-0. p.120-121.

Lichty, Lester- C, Internal Combu51ion liln«-ines . N.Y.: McGraw-Hill, 1939- p.3^5-351*-. Poison, J.A., Intern.I Conbu-jtion Engines. N.Y.: John /iley and Sons, 1932. p. 250-251.

Ricardo, Harry R., The Kirn Speed Internal Combustion Engine. N.Y.: Inferscience, 19^1. p.171-173* SNDIX I General Test Material

Contine Red Seal Engine Manufacturer - Continental Motors Corp. Type - Y-69 Direct Reading Galvanometer Manufacturer - Leeds & Nothrurc Co, No. 5067^3 Generator - Tachometer Manufacturer - General Electric Co. Type - AN 5531-1 Taylor Dynamometer Manufacturer - Taylor Manufacturing Co. Type HI-. Fairbanks Sc.^le Ma nu fa c turer - Fa i r bank s Morse %. Co. Tyne - KI-EFF (J

APPENDIX II plr- Calculations

Load on Dynamometer Scaler 20.80 lbs. Engine R.P.M.^ 1 Heating value of fuelt 20000 Btu per lb. B.H.P. - 25^5 Btu per hour 3 H p = load on dynamometer scale x R.P.M. 6000 _ s.e.o x 15^0 __ p 9n 6000 - 2'20 Thermal Efficiency & 25U-5 x B.H.P. 20000 x Fuel consumed per hr. - 25^5 x 2.20 - o uA; " 20000 x .<>5 x 6 ^ 8AW -^ />^P - -if^^WBF Z. ^^3 7V d?

.-—-.-j-l^fr /•'V'tfiiiiito

26 FORM 5000 ••-•<••"!

FORM 5000 rut ai -, • • , • • f .HV tooo THE ij -.: II , , • I • ,j FORM 5C00 THL • FORM 5000 TilL ^t-:-1 fCRr* SCCJO ,