Developments in Fuel and Power
France - The Internal Combustion Engine
PARIS, Jan. 9
In connexion with the recent Motor Show and Aeronautical Exhibition held here, an interesting congress was held relating to the use for navigation purposes of motors working on the explosive mixtures and internal combustion engines. Navigation in its various forms seems to offer a large opening for this class of motor. In the case of the navy, they would appear to be well adapted for vessels of light draught and for submarines; for the mercantile navy they can be used with advantage in vessels of moderate power; for pleasure purposes such motors are well suited for small yachts and racing boats; and for internal navigation they can be employed with success for barges and tow-boats.
The chief aim of the congress was to define clearly the type of motor which seems likely to answer best for each of the above purposes, and the question of screw propellers was also brought forward.
THE QUALITY OF FUELS
The first question that arose was the quality of the fuel. The combustible fluids which are now actually available are petroleum spirit, light petroleum oil, alcohol, benzine, shale oil, and the heavier oils distilled from coal; lastly naphthalene and producer gas are also entitled to consideration.
Petroleum spirit, or petrol, is relatively costly, and it is thus only capable of being used for pleasure vehicles or for racing cars; moreover, the danger due to its ready inflamability is much more serious at sea than on dry land. Mr. Renault has pointed out how this danger may be diminished by the use of petrol tanks, constructed with a dependable thickness of metal, the space between the two skins being filled with sand. It is expedient that the carburettor should be placed as far as possible away from the motor.
This fuel has an advantage of being cheaper, when it is used for marine purposes, as in this case it is free from Customs duty. These are excellent types of combustion engines for using the petrol, which give complete satisfaction, and their employment for fishing boats would appear to be expedient. There can be no doubt that, by the adaption of this type of motor to fishing smacks, the greatest possible service would be rendered to the French fisheries, and Mr. Lumet shows that there is a great opening for the production by the motor trade of an engine of this kind. There are, however, many precautions needed in the selection of a fuel-oil for such a purpose as this. Messrs. Guiselin and Ventou-Duclaux have shown that the most advantageous composition of the requisite fuel corresponds with a mixture of light oils, not too readily inflammable (flash point 20deg. to 25deg. Centigrade), adapted to effect a rapid and regular carburation, and thus to favour the start off, combined with some of the more heavy distillates of raw petroleum, which come over first. These latter must be well rectified, that is to say, they must boil under 300deg. Centigrade. The mixture of these constituents must have undergone a most careful process of refining.
Mr. Grebel, who has advocated for some years past in France the use of benzoline for motors, has shown that this product, a great part of which could be furnished by French gas works and coke ovens, gives good results in ordinary internal combustion engines. At the respective price of 26f. per hectolitre for benzoline and 35f. for petrol (inclusive of Customs duty), it is possible to effect a saving of from 15 to 20 per cent, per kilometric ton in the cost of transport. He has likewise proved that the tar distilleries, coke-oven plants, and gas works were in a condition to furnish at a reasonable cost large quantities of heavy coal-oils capable of being used in Diesel motors. The employment of benzoline for ordinary motor-car engines only involves a different system of regulation for the carburettor. In order to maintain the level constantly at the same height in respect to the aperture of injection, it is necessary to weight the float. The opening for the jet must also be reduced in area by about 10 per cent. Finally, Mr. Grebel recommends the extra heating of the carburettor by means of a contrivance using the exhaust gases, and it is advisable to expedite a little the passage of the gases towards the combustion head.
In the case of the use of alcohol, its employment for the engines of motor-cars has on numerous occasions been shown to be practicable, but its price is such as to exclude it from competition, even with petrol, except in Paris where the latter is charged with heavy supplementary dues.
The shale oils are utilized successfully for Diesel motors and the employment of naphthalene has recently received considerable attention. Mr. Ventou-Duclaux has described the experiments of Messrs. Chardon and Lion. The naphthalene having been melted by making a start during an interval of from 8 to 10 minutes with petrol is maintained at about 80deg. Centigrade, and is admitted at this temperature into the carburettor along with the air heated by admixture with the exhaust gases. The trials they describe took place with a tractor wagon having a second heavy van attached to it as a trailer. The entire load was eight tons, and the four-cylinder motor was rated at 45 H.P. The cylinders had a diameter of 140 mm. with a stroke of 150 mm. The amount of fuel consumed was 9 kg. of naphthalene and from 15 to 16 litres of petrol per hour.
The cheapest fuel oils are undoubtedly the heavy oils derived from coal or petroleum, and the Diesel motor would seem to be the best adapted to work in this class of fuel. Mr. Bochet has made a detailed study of this subject and has recorded the results recently obtained with this motor for the submarines of the French navy. The shipbuilding yards on the Loire at St. Nazaire are about to carry out practical trials with respect to the possibility of the employment of this motor for larger vessels, that is to say for ships with engines of 20,000 to 30,000 h.p.
THE GAS TURBINE
Mr. Lemale presented a highly-interesting report on the progress accomplished with turbo-compressors. Multicellular compressors employed for blowing purposes are in actual use in the navy for the supply of the air blast to the furnaces on warships. The application of multicellular air-compressors coupled to turbines is daily extending. he pointed out further that the improvement secured by the results of working this kind of apparatus would shortly render it practicable to employ the petrol-driven turbine. This question of the use of petrol for turbines has been under trial for some years past by Messrs. Armengand and Lemale, and a 300 h.p. machine is now actually being tested. The difficulties encountered by the inventors were two-fold in character. In the first instance it was necessary to compress the mixture of gases in a special chamber, and the compressors formerly employed absorbed nearly all the power developed by the engine. On the other hand the high temperature evolved by the combustion of the petrol rapidly destroyed the metal work of those parts of the engine with which the gases came in contact. The Creusot works are now supplying nickel steel which attains its Maximum resistance at a temperature of 250deg. C. and it is contemplated that it may ere long be possible to produce a steel which shall reach its Maximum strength at a temperature of 600deg. C. When this has been accomplished on a commercial basis, all the difficulties which confront Mr. Lemale in the definite realization of the problem of the petrol turbine will be removed.
The subject of screw propellers was alluded to on several occasions during the congress, but it was not fully debated. The great interest now taken in matters pertaining to aerial navigation caused certain of the discussions to turn to the question of aerial propellers. From the observations made it would seem that the numerous investigators are dealing with this matter. It was laid down that it was essential to carry out experiments with screws moving in the direction of their axes, and not with fixed propellers. This might be done for instance with hydroplanes provided with air propellers. it would likewise be a matter of interest to carry out a series of tests with several screws mounted on the same shaft. Reports were also presented by Messrs. Tellier and Sacconney on the question of hydroplanes.
(Transcribed from the Times of London, Jan. 13, 1909, p. 17. )
[Thanks to Greg Calkins for help in preparing this page LF]
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