IMPORTANT PAPERS AT THE ROME CONGRESS.
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Mr. Shave's Masterly Treatise on Motor Fuels and Fuel Economy and Colonel Hacking's Statement on Motors in Municipal Service.
fr1HE sittings of the World Motor Transport Con gress commence in Rome to-day (Tuesday) and continue until Friday next, Of the papers submitted by representatives of Great Britain the two which are of the greatest importance are that by Mr. G. J. Shave, who is a Government delegate and who deals with the question of motor fuel and fuel economy, and that by Colonel Alfred Hacking, D.S.O., representing the Society of Motor Manufacturers and Traders, who deals with the use of motor vehicles by local-government authorities in Great Britain. We ,propose to outline the contents of the two papers.
Mr. Shave, in dealing with the question of motor fuel and fuel economy, will refer to the conditions and limitations to be met in providing suitable types of fuel to serve the needs of the several different classes of mechanical road transport at present operating on the roads of Great Britain, in the hope that It may prove of some assistance to those responsible for the direction of research and production in respect of fuels intended for use In this type of internal-combustion engine.
Motor Spirit of the Early Days.
In the early days of development of the motor vehicle a fuel was demanded which would, at all costs, ignite with the least possible provocation, since the means tif ignition were primitive and frequently unreliable. This was met by a straight-run product of low specific gravity, approximating .680 to .700, with a boiling range of about 60 degrees C. to 150 degrees C. The spirit was, however, of a badly detonating character and necessitated the use of a very low compression. Spirits of higher specific gravity were, of course, known at the time. The diminishing supply of the very light grade of fuel at an economic price, coupled with a realization that high efficiencies were to be obtained by raising the compression pressure, led to experiments in the possibilities of utilizing a blended type of fuel.
The heaviest specific gravity fuel yielded the more economical performance, partly because of its higher calorific value per gallon. The value of aromatic hydrocarbons as anti-knock agents is now fully recognized and advantage is taken of them. Thus, in 1910, Shell ordinary petrol had a specific gravity of about .720, whereas in 1922 it was as high as .765. In 1925 the specific gravity had dropped to about .740, and it was becoming common for a fuel to be a blend, not of two constituents, bit as many as seven, each drawn from a different oil field.
The desirability of including the lower fractions is self-evident, owing to their importance in regard to ease of starting and acceleration. In respect of the limits imposed unon the higher end of the boiling range, these may be said to be set by practical considerations in regard to a design of engine and auxiliaries.
Modern petrols at present in use in Great Britain may broadly be classified into No. 1 spirit used for pleasure cars, No. 2 commercial petrols used for goods transport and provincial motorbuses, and No. 3' a special spirit used by the L.G.O.C. The characteristics of these three fuels are set out in the following table:— An important development of recent years is the expedient a increasing the yield of motor fuel by the s30
process of cracking. An objection to cracked spirits in general is the somewhat objectionable odour of the unburned spirit and also in some cases of the exhaust fumes. Some of the less satisfactory types of cracked spirit show a ,tendency to the formation of gummy deposits. The cracked spirit, however, has come to stay and is bound to be more widely utilized, since the advantages of increasing the sources of motor fuel are self-evident and, moreover, the unsaturated hydrocarbons present in the fuel possess quite good antidetonating value.
The Diesel Engine and its Fuel.
Considerable possibilities of utilizing yet greater proportions of the heavier fractions of crude petroleum undoubtedly lie in the development of the solid injection or semi-Diesel type of engine. Certain difficulties exist in connection with the distribution of the fuel or delivering of the correct quantities, according to the vehicle speed required, but these being overcome, it remains to be found whether an engine can be produced which, whilst fulfilling the necessary requirements in respect of weight, compares favourably with the petrol engine in so far as reliability and low cost of maintenance are concerned.
Alternative bases other than petrol for the production of motor fuels will assume more importance in the not distant future, especially in those countries which are, themselves, devoid of petroleum deposits. Perhaps first in importance—at any rate in Great Britain—is the production of motor fuel from coal, and a large amount of experimental work has been done in Great Britain by the Fuel Research Board in regard to the low-temperature carbonization of coal, although no process is as yet being worked commercially. It has been carried on commercially in Germany, but it should be remembered that coals are available in that country which are more suited to the treatment than are those of Great Britain.
With regard to the use of gas producers employing either coke or charcoal, this form of fuel would only be applicable to certain limited forms of vehicle transport.
The use of power alcohol has been the subject of considerable experiment; the greatest objection which must be faced in connection with its use, at any rate so far as this country is concerned, is the fact that it is practically impossible for it to be produced at a price competitive with that of other liquid fuels.
What is required of Fuel.
The principal requirements of the vehicles in which fuels are intended to be used may be summarized under the following heads: ease of starting and rapid acceleration; the need for guarding against dilution of lubricant; the absence of pungent and sickly odours end of any tendency to " creep "; the avoidance of variations in respect of specific gravity, general volatility ; the highest useful compression ratio in any one particular brand of fuel and the absence of corrosive effects.
With the exception of ethyl aleohol and benzole there is very little knowledge as to the actual performance, under practical conditions, of fuels derived from sources other than petroleum. It is more easy for a concern operating a large fleet of vehicles to Switch from petrol to such a choice of fuel, because it will be possible to segregate a number of vehicles to use the Qther fuel exclusively. It is, however, clearly impossible at the present time to predict which of the choice of fuels will first become available and, during tha transition period to the use cf another fuel, it must give a practical performance comparable with that of the petroleum product which it would replace, although where 'operating conditions are much less restricted scope is offered for a more diversified selection of fuels.
Mr. Shave proceeded at this point to consider several special features of design and method of maintenance which experience with a large fleet of the passengercarrying type of vehicle indicates to be of value in obtaining the maximum economy of fuel consumption under actual operating conditions, dealing, not only with the engine and its auxiliaries, but with the transmission of the power to the road wheels, embracing such matters as lubrication, provision of the most suitable gear ratio for the gearbox and rear axle, the employment of pneumatic tyres and the influence of chassis and body design upon fuel economy.
Colonel Hacking's Paper.
Colonel Hacking, in his paper, stated that the use if mechanical transport by local authorities in Great Britain may be divided under three heads; 1, passenger-carrying vehicles; 2, public health vehicles; 3, public safety vehicles; the first being the most important in that the motor omnibus and railless traction vehicle constitute the latest development of municipal passenger transport, following upon the adoption last century of the horse tram and, later, the steam tram, and, finally, the electric tram.
Progress in the adoption of the motorbus by municipal authorities along new routes, sometimes within but frequently without the borough boundaries, has been rapid since the war, and there are to-day some 75 local corporations in Great Britain operating motoromnibus services. Parliament has deliberately adopted the policy of eneouraging local authorities to provide facilities for the transport of passengers and, to some extent, of goods, the Tramways Act of 1870 making the necessary provision for the construction of tramways by local authorities or companies. Local
authorities, however, were not allowed to work the tramways, but were obliged to lease them. In 1893 it became the established practice to sanction the working of tramways by such authorities. Many undertakings have been provided and worked by local authorities under the Light Railway Act of 1806. Parliament proceeded very cautiously in the first instance in permitting local authorities to provide and work buses. It was in 1902 that the Eastbourne Corporation obtained general powers to run buses anywhere in its borough and for a prescribed distance beyond the borough.
Municipal Bus Estimates.
A fair estimate of the number of buses owned by authorities in Great Britain in the year 1927 was 1,940, carrying 283,000,000 passengers and having a total gross income of over £2,650,000.
During the past few years a beginning has been made of the conversion from rail-tram systems so motoromnibus systems, whilst the railless traction vehicle has been substituted by the tram in different places with varying success. Amongst other types of vehicle used by local authorities are staff cars (many of them of the utility type), borough surveyors' vehicles, street cleansing vehicles with special bodies for different purposes and fire-engines, there being probably over 700 motor fire-engines of one type or another owned by local authorities.
Mechanical road transport has thus become an essential and ever-growing part of the work of the local authority in Great Britain, and, as time goes on, it cannot be doubted that authorities, charged with She duty of maintaining public health and discharging in the interests of each community their many and growing obligations to the public, will be forced, to an even greater extent, to rely upon the various forms of mechanical road transport produced by the vision and energies of the motor-manufacturing industries of the world.