The principles of the application of power to road transport; (a series of six lectures delivered at the Technical College, Finsbury) - Tapa blanda

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1913 Excerpt: ...is that whereas in the latter the power depends upon the engine alone, in the former the primary source of power is the boiler. The boiler is capable of supplying steam at a certain average rate, and in the long run the engine can only develop power at a corresponding rate. By drawing on the reserves of steam in the boiler it may produce for short periods an amount of power greatly exceeding the average, but, unless the boiler be a very large one, such periods of over-load will result in a drop of pressure, and must be set off by periods of comparatively light load, during which the boiler can make up the pressure again. In a steam car, as in other cars, the engine is only occasionally called upon to develop its full power, and the average is much less than the maximum. These short spurts at high pressure can be provided for by a comparatively small boiler--a boiler quite incapable of producing steam at that rate continuously. The maximum power available for short periods--say, in ascending a hill--is determined largely by the size of the engine. But the average power on a long run depends solely on the boiler. The power of a steam car ought to be taken as 1 "Report of Treasury Committee on H.P. Rating of Motor Cars, 1912." proportional to the capacity of the boiler for evaporating water, and this depends upon the heating surface, and on the rate at which the burner can consume fuel. The ideal rating formula for steam cars would be based simply on these quantities, and would be independent of engine dimensions. The capacity of a boiler depends upon the heating surface exposed to the flame and on the arrangements for burning fuel. With equally efficient burners the capacities of different boilers will be in proportion to their effective heating sur...