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Viewing 16411 to 16440 of 16636
1939-01-01
Technical Paper
390123
A. T. McDonald
DATA are presented to show that compounded lubricants for use in the lubrication of high-speed Diesel engines have come to be regarded as indispensable, and to demonstrate their influence in high-temperature operation on engine deposits, oil deterioration, and strength and corrosion of bearing metals. The author divides filters into two general classes: the adsorbent type and the absorbent type. Adsorbent filters, the paper explains, incorporate in their composition Fuller's earth, charcoal, or other adsorbent materials and attempt to incorporate features which have as their object the refining of oil. Tests are described, the results of which lead the author to the conclusion that such filters remove addition agents used in compounding Diesel engine lubricants to a surprising degree and, therefore, are detrimental in such applications.
1939-01-01
Technical Paper
390146
H. Blok
IT does not yet seem to be recognized fully that it is the local temperature at the surface of contact and not the local specific pressure that chiefly determines the occurrence of seizure under extreme-pressure-lubrication conditions. This local temperature is the result of the temperature level of the parts lubricated, considered as a whole (“bulk” temperature) and of a superimposed instantaneous temperature rise (temperature “flash”) which is localized in the surface of contact. It appears typical for extreme-pressure-lubrication conditions, as met in gear practice, that the temperature flash is much higher than the bulk temperature. With existing conventional test methods for the determination of the protection against seizure afforded by EP lubricants, a considerable rise of the bulk temperature mostly occurs; as it cannot be controlled sufficiently; thus, leaving an unknown margin for the temperature flash, it renders impossible a reliable determination.
1939-01-01
Technical Paper
390137
A. F. Robertson, R. A. Rose, G. C. Wilson
NOT only does a high-cetane diesel fuel start to burn earlier in the cycle due to its shorter ignition-lag period, but it continues to burn longer during the expansion stroke than does a low-cetane fuel, the authors announce. This and other findings, they explain, are the results of an investigation of the effect of fuel quality and injection advance angle on ignition lag and combustion duration in a 4-cycle high-turbulence diesel engine. The same photo-electric combustion indicator, developed at the University of Wisconsin, was used, they point out, as was described previously before the Society, with the exception of several improvements. Combustion characteristics of 27 different fuels were determined by studying the oscillograms for more than 5000 engine cycles obtained at a film speed of 60 fps. From dynamometer tests run both on 1-cyl and 6-cyl 4-cycle diesel engines, fuel rates were obtained from six different fuels varying in cetane number from 25 to 87.
1939-01-01
Technical Paper
390018
R. Stansfield, H. B. Taylor
1939-01-01
Technical Paper
390121
E. L. Bass, C. H. Barton
IT may be necessary to compromise among the ring-sticking, sludge-forming, and corrosion properties of oil for civil aircraft engines, the authors suggest. No laboratory tests are yet able to predict the performance of an oil in an aircraft engine, they contend, and therefore, full-scale engine tests are necessary for final judgment. However, they explain, much preliminary work can be carried out in suitable small units. To illustrate the complexity of the problem the authors set forth five requirements for an aircraft-engine lubricant: 1. It must not cause ring-sticking under the full-throttle detonating conditions of take-off. 2. It must not cause ring-sticking under weak-mixture cruising conditions. 3. It must give freedom from sludging so that there is no ring-jamming, so that the oil scrapers are kept free, and so that the overhaul periods are not limited. 4. It must provide protection from cold corrosion. 5.
1939-01-01
Technical Paper
390157
Frank C. Mock
RECENT developments in fuel-refining processes have developed new safety fuels, and have revived general interest in the subject, Mr. Mock reports. “Safety” or fireproof aircraft fuels, he explains, must be less volatile than gasoline and should have a flash point of about 105 F, a distillation range between 375 and 475 F, and about 87 octane rating. In his paper he summarizes the program probably necessary before such fuels can be employed successfully in every-day service operations. Three methods of fuel feed are discussed: injection into the cylinder, into the intake pipes, and into the supercharger. Injection into the cylinder, he reports, has been tested on a full-scale engine on the dynamometer with some success, but it was not flown. Injection into the supercharger, he feels, is attractive because of its simplicity. Five detail problems are listed: injection equipment; changes in engine and cylinder; fuel-air metering and power control; starting; and installation.
1939-01-01
Technical Paper
390170
F. R. Banks
FUTURE engine developments for powers between 2000 and 4000 bhp and the author's views on the form which such engines will take, together with optimum cylinder sizes and number of cylinders, are covered in the latter part of Mr. Banks' paper. Because it concerns the possible future development of military aviation in America as well as his own Country, the author considers this part the important one. In the first part, he gives a short résumé of the aviation fuel position in Great Britain, and then goes on to describe some work which he has done in conjunction with the British Air Ministry and one of the aero engine manufacturers on very high-duty aviation engines. He also discusses what, in his opinion, is a characteristic of the American two-valve hemispherical cylinder head relative to British four-valve engines in regard to fuel behavior. He continues, mentioning certain new developments, such as the treatment of poppet type exhaust valves with Brightray.
1938-01-01
Technical Paper
380030
L. B. Kimball
1938-01-01
Technical Paper
380027
C. G. A. Rosen
1938-01-01
Technical Paper
380001
J. A. Moller, H. L. Moir
1938-01-01
Technical Paper
380005
C. M. Larson
With 1,250,000 tractors in use today, the question of tractor engine wear in relation to lubrication becomes a very important study. Yet the problem is a very complex one, as the types of fuels vary greatly, the load conditions and time of continuous operation are seldom the same, dust fall is between two and ten tons per square mile per day, and the operation-service, care and engine rebuilding may be doubtful. Besides this, engine design, combustion rates and bearing materials all add to the variables in selecting the adopted lubricant. Clean air, efficient fuels, adopted lubricant and proper care of operation and service are factors affecting wear of a given tractor engine.
1938-01-01
Technical Paper
380168
J. R. Sabina
NO change in the method for correlating road and laboratory ratings is recommended, this report concludes. The failure to achieve better correlation, it explains, is not due primarily to shortcomings of the data, but to the failure to take cognizance of all the factors influencing car ratings. Furthermore, it reports, no material improvement can be expected from accumulation of additional laboratory data involving only speed, temperature, and spark advance. At the November, 1936, meeting of the Cooperative Fuel Research Committee the study of the correlation between laboratory knock ratings and road ratings in the then-current automobiles was authorized. The outcome of a preliminary study, based on information submitted by individual companies in 1934, 1935, and 1936 cars, indicated the desirability of collecting cooperatively road and laboratory data under controlled conditions for a more accurate evaluation of the correlation problem.
1938-01-01
Technical Paper
380166
Stanwood W. Sparrow
MR. SPARROW'S paper emphasizes the importance of the question: “What is the minimum safe viscosity for an engine oil?” Although he does not attempt to solve the problem, he presents material “accumulated as a by-product of routine engine tests and development,” which, he says, indicates that rather low viscosities may be safe for bearings if and when we can be sure that the amount of lubricant which reaches the bearings will be adequate. He adds that it also indicates the extent to which safe lubrication of the cylinder bores depends upon the ability to produce and maintain smooth surfaces on pistons, piston-rings, and cylinder walls. He illustrates how a low viscosity is effective in increasing cranking speed and in reducing friction -thereby producing a gain in horsepower and fuel economy. He also cites examples to show the extent to which low viscosity is detrimental as regards oil consumption, blowby, and the protection which the oil film affords to the rubbing surfaces.
1938-01-01
Technical Paper
380170
By A. J. Blackwood, C. B. Kass, G. H. B. Davis, G. H. B. Davis
PRESENT methods of correlating road knock behavior of fuels with laboratory methods are unsatisfactory and should be discarded in favor of a method that makes a new approach to the problem, the authors contend. Reviewing the causes of this situation, the paper offers evidence to show that the use of mathematical averages applied to the study of the car detonation problem has been very misleading and that the so-called average fuel octane-number requirement of existing cars and its corollary, the octane requirement of the average car, are values having little practical significance. A procedure is recommended by the authors as one approach to the problem of setting up a simple, practical way of evaluating fuels. It consists in selecting a number of privately owned cars and testing both reference-fuel blends and branded fuels in these cars without making any changes whatsoever in the engine adjustments. The results of two such surveys are reported.
1938-01-01
Technical Paper
380169
John M. Campbell, W. G. Lovell
CONCLUSIVE evidence that any one make of car has a real, as distinguished from accidental, tendency to rate fuels higher or lower than the average for all cars is difficult to find in existing data, the authors report. The growing economic and technical importance of antiknock quality, they point out, is making it increasingly desirable to estimate the random distribution of errors that occur in making measurements of knock, either in the laboratory or in road tests. Statistical analysis, they explain, offers a means of appraising the probability of occurrence of errors of various magnitudes. To make a beginning in such a statistical analysis of the available data on fuel ratings is the purpose of their paper, they announce. The variability, or random error, among successive measurements in road tests was from three to six times higher than the variability among measurements of octane number in the A.S.T.M.-C.F.R. single-cylinder test engine, the paper reports.
1938-01-01
Technical Paper
380158
C. F. Prutton, A. O. Willey
IN the work reported in this paper the performance of several recognized commercial types of hypoid lubricants has been studied and a comparison made of a number of test methods including: film-strength machine tests; various types of continuous-load tests; laboratory shock tests; and road shock tests. This work has been in progress for more than fifteen months, has involved more than 50 lubricants, and more than 150 individual gear tests, each test requiring the use of a new set of gears. The results of these tests indicate deficiencies in some of the lubricants under certain of the extreme conditions employed. Of the commercial lubricants studied, those that passed the laboratory shock test lubricate hypoids quite satisfactorily under practically all other test conditions where normal temperatures were used. The performance of the lubricants in the gear tests seems to bear but a slight relation to film-strength data as obtained on laboratory test machines.
1938-01-01
Technical Paper
380149
J. R. MacGregor, W. V. Hanley
FUEL deposition and ring-sticking tests are described which were performed in several single-cylinder and multicylinder service Diesel engines in the laboratory. The development of an accelerated test method is outlined with special reference to the effects of engine variables on deposition. Decrease in load, speed, or jacket temperature or increase in altitude were found to increase fuel deposition. Increase in running time increased the exhaust deposits linearly but, within the combustion-chamber, equilibrium deposition was reached in a few hours of operation. Marked differences were found among fuels in the single-cylinder test engine after 24 hr. of operation under the accelerated conditions. Fuels doped with different types of cetane-number improvers indicated that ignition quality is a factor in fuel deposition under certain operating conditions in some engines.
1938-01-01
Technical Paper
380154
G. A. Round
1938-01-01
Technical Paper
380145
T. A. Boyd
THIS paper deals with the road-test portion of the extensive efforts made during 1937 by the Cooperative Fuel Research Committee to get as precise a correlation as possible between the laboratory knock ratings of automobile fuels and their corresponding ratings in cars on the road. It is anticipated that the comprehensive results of car tests reported here, taken together with the results of the laboratory rating program reported in the companion paper, will serve as the basis of the continuing studies aimed at developing the best possible correlation between road and laboratory knock ratings. Work similar to that reported here has been conducted concurrently in England by the Institution of Petroleum Technologists, using British cars and fuels. An exchange of information between the British and American groups working on this problem is being made.
1938-01-01
Technical Paper
380125
A. E. Becker
THIS paper is a progress report of the Cooperative Fuel Research Committee, dealing with the laboratory section of the study of the knock-rating correlation problem. It is proposed that these results and those obtained on the road be the basis for further study aimed at the development of better correlation between road and laboratory ratings.
1938-01-01
Technical Paper
380121
C. H. Baxley, T. B. Rendel
FOLLOWING the adoption of a suitable design of engine and a tentative procedure for operating this engine, the work of the Volunteer Group has covered the investigation of other methods of measuring cetane number of Diesel fuels looking towards a simplification and improvement of reproducibility of the procedure. Results of a second series of cooperative tests are given, using the procedure adopted in the Group's last report together with a series of tests on the same fuel using the critical-compression-ratio method with an interval timing-control device. Results of the first series do not show such good agreement, the grand average deviation on twelve samples being of the order of ±1.9. Results of the critical-compression-ratio tests show improved agreement due to better standardization. Tests on three alternative methods based on the delay method, but using different instruments for recording the delay, are given. Results on two different full-scale engines also are presented.
1938-01-01
Technical Paper
380113
M. J. Zucrow
1938-01-01
Technical Paper
380084
Joseph Geschelin
1938-01-01
Technical Paper
380079
C. F. Lienesch
1938-01-01
Technical Paper
380076
D. E. HAMILTON
1938-01-01
Technical Paper
380054
A. George, W. Brown
1938-01-01
Technical Paper
380112
T. B. Rendel
1938-01-01
Technical Paper
380032
O.C. Bridgeman, M.L. Leidig
1938-01-01
Technical Paper
380177
H. K. Cummings
DATA in this report represent work carried out in accordance with assignments made in the first report of the C.F.R. Committee presented at the 1936 Annual Meeting of the Society, as follows: 1. Establish the validity of the C.F.R. Recommended Procedure for Rating Fuels in Full-Scale Aircraft Engines for fuels above 87 octane number. 2. Conduct full-scale engine tests in the range from 87 octane number to the highest octane number available. 3. Concurrently with Assignment 1, develop or revise knock-test methods leading to correlation with full-scale engine data. The data presented are in accordance with Assignments 1 and 2, and the data required for Assignment 3 have been obtained in part. Further tests on olefinic fuels are reported.
Viewing 16411 to 16440 of 16636