152 



National Resources Planning Board 



experience. Clearly, this improvement is not to be 

 attributed to the progress in fuels alone. And, an indi- 

 cation of the relationship that e.xists between the parallel 

 lines of development of fuels and of engines may be 

 obtained from figure 37, which shows the increase in 

 compression ratio and improvement in octane number 

 by years. 



The high speed automobile engine with its high 

 power output and lightweight construction places rigid 

 requirements on lubrication. As we have already seen, 

 the petroleum industry has contributed to meeting this 

 requirement by the development of oils that retain 

 their fluidity at low temperature, show a minimum 

 change in viscosity on temperature rise, and possess 

 stabiUty toward oxidation in high temperature oper- 

 ation. The magnitude of the problem involved in im- 

 parting oxidation stability may be appreciated from the 

 fact that the oil temperature in the crankcase of a light 

 passenger car engine may reach as high as 285° F. 

 under not exceptional driving conditions, and on the 

 piston crown of a heavy-duty bus or truck engine, the 

 oil film is exposed to temperatures of 600°-700° F. 



Maintaining adequate bearing lubrication in the face 

 of increasing bearing loads is an ever-present problem. 

 The need for a change from white metal to copper-lead 

 and silver-cadmium alloy bearings, in certain types of 

 high temperature service, has introduced additional 

 comphcations. The problems have been solved, never- 

 theless, by the development of lubricants representing 

 further improvements in resistance to deterioration in 

 high temperature service and in freedom from bearing 

 corrosion. 



Special problems in chassis lubrication have been 

 solved through cooperative research, and new extreme 

 pressure lubricants have permitted the wide adoption 

 of hypoid gears for power transmission. 



OCTANE 

 NUMBERS 



COMPRESSION 

 NUMBERS 



1929 I930 1931 1932 1933 1934 1935 1936 r937 1938 I9J9 



Figure 37. — The Trends of Octane Gasoline Ratings and Auto- 

 mobile Engine Compression Ratios, 1929-39 



\Vhat has been said about the relation of petroleum 

 research to developments in the automobile field holds 

 true, in general, also for aviation — with the exception 

 that the progress in this case has been even more 

 spectacular from the standpoint of both accomplish- 

 ments and the speed with which the results have been 

 forthcoming. 



Only a few years ago the aviation industry had be- 

 come standardized on a 73-octane-number fuel which — 

 on the addition of 3 cc. of tetraethyl lead per gallon — 

 could be brought up to 87-octane-number. The 

 horsepower output in general did not exceed 40 horse- 

 power, per cylinder. At present, engines of well over 

 100 horsepower, per cylinder, are running on fuels of 

 up to 100-octanc-number, and a great deal of research 

 effort is being expended by the aviation and petroleum 

 industries on extending these limits still further. By 

 going from an aviation gasoline of 87 to one of 100- 

 octane-numbcr, it has been possible to effect a 15- to 

 30-percent increase in power for take-off and climbing, 

 or a 20-percent reduction in cruising fuel consumption. 

 Where engine design or performance requirements are 

 such that full advantage cannot be taken of the 100- 

 octane-number fuel, fuels of intermediate octane 

 ratings are satisfactory and are finding a wide field 

 of use. 



Aviation superfuels, as fuels of 100-octane-number 

 or over are sometimes called, are usually mixtures of a 

 special aviation gasoline base stock, and blending 

 agents, synthetic or natural, to which have been 

 added 3 cc. of tetraethyl lead per gallon. The syn- 

 thetic blending agents are produced by the previously 

 mentioned polymerization and alkylation processes. 

 The capacity for alkylation, either in operation or 

 under construction, has within about 2 years reached 

 some 12,000 to 15,000 barrels a day. To provide 

 sufficient base stock of suitable high octane number, 

 the natural supplies are at present being augmented 

 by high pressure hydrogcnation. 



In the 7 years from 1932 to 1939 the gasoline con- 

 sumed by Government and civil aircraft in the United 

 States increased twofold, from 54 to 108 million gallons 

 annual^. During this same period the improvement 

 in aviation lubricants led to a decrease in consiunption 

 of from 1 gallon of oil per 37 gallons of gasoline to a 

 ratio of 1 to 42.« 



Other Industries Affected 



It would be practically impossible to enumerate all 

 the industries which in one way or another have 

 benefited directly from the technical accomplishments 

 of the petroleum industry. A plentiful supply of 

 heavy fuel oil has had a profound effect on develop- 



• Norman, H. Stanley. Aviation gasoline assaming Increasing Importance. T\f 

 Oil and Oat Journal, 38, No. 44, 21 (March 14, 1940). 



