Oil Engines for Traction Purposes
Page 49
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MHE first of a series of three papers on Oil-engine
Trac
tion, by Mr. Alan E. L. Chorlton, C.B.E., M.P., M.Inst.C.E., M.I.Mech.E., was read by its author at the Royal Society of Arts, London, on March 7th. The chair was taken by Sir Lincoln Tangye.
The second and third of the series are being read during this month, and, after the completion of the course, the three lectures will be published in amphlet form, and may be obtained at the price of 2s. 6d. from the secretary of the Royal Society of Arts, 18, John Street, Adelphi, London, W.02.
The major portion of the first lecture was devoted to the application of the oil engine to work on rails, and Mr. Chorlton made many interesting comparisons between steam, electric, oil-electric, and oil power.
Coming to the question of road traction, he said that the problem of substituting the oil type of engine for the petrol unit had been extremely well tackled.
He pointed out that, in the latest designs of oil-engined vehicle, progress had been such that a weight of only 10i lb. per b.h.p. had now been attained, which he considered a very satisfactory figure indeed for a power of 130 b.h.p. Such a vehicle, he added, could accelerate as fast as most suburban electric trains, in spite of the use of friction clutches and conventional gearboxes, and it might naturally be expected that transmission systems would come in for more consideration.
He considered that the limit of the " step " type of gear seemed to have been reached, and that present indications pointed to electric transmission or to modifications based on a more gradually acting slipping device than the older friction clutch, and a gearbox with the wheels in constant mesh, the change from one ratio to another being made without jar and break of torque.
Two respects were named in which the road led the railway, namely, the practice, of streamlining, with its great advantage at high speeds, and that of employing ball and roller instead of plain bearings.
To prove his statements on the subject of acceleration, and to demonstrate the excellence of modern braking systems, as compared with the performances of electric rail trains, he quoted figures obtained from actual tests of A.E.C. and Leyland standard 10-ton buses.
A feature of the road passenger vehicle, to which he drew attention, was the light weight per passenger. "It is remarkable," he said, "that this, equal to five or more passengers per ton, is so effectively eitrried out."
Besides the reduction of weight, without sacrificing reliability or low upkeep charges, the first coat of engines for road work had been brought down more than in the case of engines for use on the rail, which fact was of predominant importance in accounting for the greater rapidity of the use of oil engines on the road.
In conclusion, he quoted the following approximate figures, which form an interesting comparison of the weights and costs of the two forms of passenger transport.