The Institution of Automobile Engineers.
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An Address on the Fuel Problem.
The first meeting of the 1913-1914 session, of the Institution of Automobile Engineers, was held in London on Wednesday of last week. The proceedings were opened by a presentation of the Crompton medals of the Institution to Colonel R. E. Crompton, GB., Mr. F. W. Lanchester, and Mr. L. A. Legros, past presidents, in recognition of their rah-et/ate' services. The presentations were made by Mr. T. B. Browne, the retiring President, who announced that Dr. Dugald Clark and Dr. Hele-Shaw, to whom Crompton medals had also been awarded, were unable to be present that evening to receive the honour personally.
Mr. J. S. Critchley, M.I.Mech.E., the new President, opened his address by a. brief review of the growth of the Association in all branches. He had chosen the subject of "The Fuel Question" because the automobile engineer had seriously to consider the future prospects of obtaining a fuel suitable for the internalcombustion motor, and to do so at a price which would not impede the development of the industry.
Concerning Heat Values.
We make certain excerpts from. Mr. Critehley's address, and the first of these appears to disclose a, discrepancy which may call for a word of explanation. We do not exactly follow why the losses in use are not a:so deducted in order to find the ultimate costs of he useful heat in the fuels other than petrol.
Petrol is to-day about the most expensive fuel that can he employed commercially for power production. Taking its cost at 20. per gallon, approximately 7000 B.Th.U. will be obtained for one penny, suit' allowing for the loss in motor efficiency and the transmission losses, only about 1500 B.Th.U. for one penny remain, while crude oil at 30. per gallon would give some 40,000 'fl.Th.C. for the penny, coal at 18s. per ton would give about 62,000, and coal gas at 2s. 6d. per 1000 cubic ft. some 23,000 B.Th.D. With petrol at its present prevailing price it is obvious that the automobile cannot be compared in economy with other types of motors in which a cheap-'r foci is employed.
Consumption and Prices.
The growth of petrol imports and the fluctuations of prices next receive attention.
The following table gives the imports of petrol into Great Britain and the retail Prices* from the year 1902:—
Mr. Critchley next proceeded to quote certain interesting points concerning views and experiences in the United States. The calculations in regard to the maximum possible running per working day, if all internal-combustion engines were used regularly, are certainly most suggestive.
Referring to the decreased output, the United States Geological Survey states : " That the decrease of production would doubtless have been much greater but for the effort to apply laws of supply a-nd demand by increase of prices. Prices have advanced so greatly as to stimulate drilling even in the old New York and Penes,ylva,nia fields, and so checked the decline." The price of petrol on the West Coast of America is now 15d. per gallon. Professor Magruder, of Ohio State University, calculates that in addition to the motorcar engines there are 1,000,090 motors used for farm work and motor boats, and that taking the average horse-power of car motors at 25 and that of other motors at 10, 35,000,000 horse-power of gasoline engines are available for the practical generation of power. He assurms that each motor uses a maximum at rated load of 0.75 pound, or one pint., of gasoline per horse-power per hour, and that the total requirements of gasoline would be approximately 4,500,000 gallons per hour. The total annual supply of gasoline in America is estimated at 1,500,000,000 gallons, which would last. only 333 hours, If, therefore, every gasoline motor were run at its rated load each day the annual distillation of gasoline would only permit them to be operated for about one hour per day or 333 hours per year. In other words, the present supply of gasoline is sufficient to operate continuously at their rated load only 5 per cent. of the gasoline engines now sold and in operation. In Great Britain, the. estimated amount of petrol which will be consumed during the current year is 100,000,000 gallons. The total registration of vehicles in Great Britain in 1912 was 188,874, showing an increase of 28,982 over the preceding year. A considerable number of registrations are cancelled, but I think it would be safe to assume that 110,000 motor vehicles are in use. The buses and taxicabs of London number about 10,000 vehicles, and will consume approximately 20,000,000 gallons, while motor boats, motorcycles, and other users will absorb at least another 10.000,000 gallons, so that for 100,000 vehicles we have some 70,000,000 gallons of petrol consumed. Assuming that the average horse-power of each vehicle is 20, and that the petrol consumed is 0.75 pints per horse-power per hour, the 70,000,000 gallons spread over the resultant horse-power hours would only provide for the running of the vehicles 373 hours .per year, which is little over one hour per day for every day m the year. When it is considered that commercial vehicles must run at least three times as many hours as pleasure cars, it will he realized how great the increase in the demand for motor fuel must be with the increasing output and more general use of commercial vehicles.
Before pas-sing away from these considerations, Mr. Critchley directed attention to the more-important bearing of fuel cost upon commercial-vehicle use, compared with pleasure-car use, by reasen of its high relation to total cost. He also made acknowledgment to our sister journal " The Motor," for its splendid activity in respect of benzole, and expressed his approval for the general use of kerosene a,ed petrol mixed in commercial motors. Arising from this, he proceeded to deal at some length with carburetters.
Concerning Carburetter Conditions.
The carburetter for an automobile must fulfil the following conditions :—The combustion must be perfect to a degree that there shall not be any offensive odour or visible exhaust the feel must be regulated to respond instantaneously to changes due to varying speed and load, and the combustion of the fuel must not deposit carbon or any other substance within the cylinder. In addition to its lack f vola,ility, kerosene has a smaller rangeof combustible mixtures with air than petrol, and greater viscosity, and it is much snore difficult to obtain the proper physical conditions for combustion than in the case of volatile liquids and gases. It is, indeed, difficult to fulfil the requirements with kerosene carburetters as we know them to-day, and I do not think we are yet able to come to a conelusive opinions as to the best method of dealing with this fluid. The provision of an apparatus for kerosene which will give uniformity of temperature and complete vaporization before the mixture enters the combustion chamber is practically impossible with a motor which is subjected to such varying speeds and loads as the present-day motor engine, and while heated carburetters such as the Stewart Morris, Standard, G. S., and many others which give more or less satisfactory results, I do not consider that anything approaching finality has been reached in connection with the method and means of dealing with this fluid, and now that real necessity has arisen not only in this but every other country for reducing fuel cost. I feel eertaM that improved methods will be found for bringing into use a fuel which contains, as far as
ite constituents are concerned, all that is necessary. One of the difficulties with the heated paraffin carburetter is to keep the temperature constant. There is, of course, one correct temperature at which a properly vaporized explosive mixture can be obtained, and this depends upon the boiling point, of the fuel employed. To ensure proper combustion it is necessary to maintain the temperature up to the point of firing. Condensation causes in the first place a weak mixture, while an accumulation of the condensed paraffin elves tee rich a mixture. In both cases a foul exhaust is the result, in addition to a bumpy engine.
The claims of various " cracking " processes were next mentioned, and certain figures in regard to achieved and prospective yields were included. The address next touched upon matters concerning creosote, bituminous coal, shale, arid alcohol. We have only space to make very brief extracts.
Creosote Prospects.
Creosote has recently been referred to as an available
material for the production of motor fuel. it is a coal tar distillate of from 0.940 to 0.980 speclic gravity. The creosote cii usually contains about 40 per cent, of naphthalene, Cracking of creosote oil has often been attempted in Germanyand given up, one reason being the sulphur content which spoiled the distillates, giving them a most objectionable smell. Again, the temperature required for distillation is very high, and success was practically only achieved at one special temperatore. Below that temperature the output of benzoic was very small, and above it the benzole turned into naphthalene. The amount of benzole obtained by this German process was about 2 per eent.
The cracking of creosote is a very much more complicated proposition than with crude oil, and, further, it is scoot tar preduct obtained with a high temperature retort distillation, a id is therefore in itself a crack produce Further development in the employment of this material will be awaited with juiciest. 'Mere is, however, no evidence as yet of nov coinnee cial treatment.
A Few Difficulties with Alcohol.
he low heat value of alcohol is due to the presence of oxygen, a portion of the carbon being, in a senev, already burnt. Alcohol has a definite chemical composition alio
therefore the air necessary for combustion call exactly cal
culated. It can only be approximately calculated for a fuel like petrol, which is a mixture of variable proportions and of a large number of different. chsmicai substances. The amount of air required for complete combustion of 90 pe.r cent, alcohol is about 9 to 1, whereas petrol of a sriecific gravity of 0.730 requires a proportion of about 15 to 1 for complete combustion. raking the heat value of the two fuels, without taking into consideration the heat units absorbed in actual work, the power is approximately 10 to 18 in favour of petrol. The boiling point of alcohol is about 170° F. ; it is therefore necessary to have some form of heated carburetter or spraying device similar to that which would be used for petroleum. Iii addition to haying 10 per cent, of water to deal with, the bent required for evaporation of alcohol is considerably greater than that required for petrol. Put into figures, about 2 times greater heat is required for evaporation of the pure alcohol, and then the 10 per cent, of water requires about fi times the amount as compared with petrol. Bo making use of the saturation equivalents of alcohol and water for air at various temperatures it is possible to find the temperature et the. air supply to the carburetter.
Professor Meyer found that of 10 alcohol motors, the one which gave the most economical results required the ingoing air to the carburetter to be raised to a temperature of about
125c' C. The important feature in connection with alcohol meters is the necessity of keeping a high degree f heat in the
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water jacket.; it has been found, n fact, that the consumption with light load and water at 15° C. is double that -when the temperature of the jacket is 100° C. At ordinary compressions the consumption of alcohol is practically 50 per cent. greater than that of petrol for the same lop. ; it is therefore necessary, when using alcohol, to have a compression which should not be less than 125 lb. and which may go up to 200 lb. Therefore, while alcohol has a low percentage of heat units, its efficiency with an engine properly constructed and with the rightcompression is greater than in the case of petroleum prnducts. The range, too, of explosive mixture with alcohol is much greater than with petrol. Mixtures of alcohol can be tired varying from 4 to 13 per cent., which is about three times the range of petrol. Alcohol vapour and air is a slow burning fuel, and with a fast running motor will continue to burn practically during the whole period of the struke, and whilst, therefore, it shows excellent efficiency with'. siow running motors it appears necessary for high speeds to look for soma. thing to increase the speed of ignition or flame propagation. There is evidence that alcohol requires 0.004 seconds more time for ignition than petrol. It would, therefore, appear desirable to add some other fuel to alcohol with a view to increasing the calorific value, and at the same time to provide for a more speedy propagation of the ignition.
French and German Experiments.
Both in France and Germany the conclusion has been arrived at Unit if alcohol is to be used it must be uniched or blended, and benzole has been tried for this purpose. The Bus Co. in Paris have made extensive trials of mixtures of alcohol and benzole, in the prpportions of 50 per cent., the consumption per kilometric ton being 0.09 litres. These motors were worked at a compression of about 100 lb. per sq. in. and ran at 900 r.p.m., and were fitted with an automatic regulator to prevent. any increase. The most efficient speed was felled to be 650 r.p.m. Experiments have also been conducted with a Mixture of acetylene gas aad alcohol. In the Barker and White system dilnted alcohol is sprayed on to calcium cubicle. It would appear that the addition of acetylene adds considerably to the speed of ignition of the vapour. Picric acid has also been suggested as an enricher of alcohol, but investigation in this direction has resulted in the conclusion that it is not practicable for the reason that picric acid when mixed with the water in the alcohol has a corroding effect on metals.
Conclusion.
In conclusion, I am afraid thatI have not., perhaps, told you much that is new, but I have endeavoured to give you a general review of the present position of the fuel situation. There is no doubt that a cheap fuel would be of the utmost benefit to commercial vehicle builders, and I am of opinion that the development of the motor omnibus is to a considerable extent due to the low price of fuel at a time when economy of working was not possible in other directions. Had the London General Omnibus Co., for instance, hem paying ls. per gallon fur fuel during' the change over to the mechanicallypropelled omnibus, J. fear the results achieved would have been quite different, aud in all probability we should not in London be served by the excellent transportation facilities we now enjoy. The question of both alcohol mid the more econonneai utilization of our coal wealth are matters of the utmost importance ; they are„ in fact, national matters. In coal we have all that we require for motor fuel, both heavy and light. I would therefore like to see the whole question of fuel supply taken in hand by a body of experts with a large sum of money to carry out research work so as to decide oil matters which are in doubt, and which can only be proved by trials and experi
ments of a costly nature. In some of our colonies, South Africa, for example, there are vast deposits of low grade coal which might be turned to account for the production of motor fuels, and other products of dietillation. This coal is of a very low grade and will not burn in au ordinary grate, and can be obtained for practically the cost of moving it, which is very low on account of the deposits being on the surface. I am of opinion that the British Empire could within itself produce all the fuel it requires, and in place of giving prizes for new fuels the money would, I am sure, be far better employed in research work on the lines indicated.