The Application of Superchargers to Automotive Vehicles

MOST passenger automobiles are overpowered and probably 80 per cent of such vehicles operate at less than 35 m.p.h. for 90 per cent of the time, according to the author. At 30 m.p.h. an average 3000 to 3500-lb. passenger-car requires from 12 to 15 hp., but the engine carried is capable of developing from 50 to 55 hp. The result is that the car is operated for the greater part of the time at one-third to one-quarter throttle opening. Full power is needed only for accelerating and hill-climbing; during the remainder of the time the excess weight of the engine and other parts must be carried at a loss of efficiency. The author maintains that smaller engines can be used advantageously when equipped with superchargers, the supercharger being used only when excess power is required. Curves and a table are given to show the results of comparative tests with and without a supercharger, and views are shown of the design and construction of a supercharger believed by the author to possess special advantages.