Atmospheric Humidity and Engine Performance
SO-CALLED correction factors to compensate for variations in atmospheric temperature and pressure have been in practical use in connection with engine testing; but the influence of the varying amount of aqueous vapor present in the atmosphere has not had sufficient consideration. The author submits brief test-data indicative of the effect of humidity on some factors of engine performance and of the feasibility of using rational power-correction factors. By assigning due importance to the effect of humidity, he believes that a more satisfactory analysis of car and of engine performance can be obtained. Using a single-cylinder engine operated at full throttle and 1000 r.p.m. under stabilized conditions, tests were made observing maximum power, air-flow, fuel-flow, detonation and spark-advance requirements over a wide range of relative humidity for an air-intake temperature of 100 deg. fahr. Curves made from the data obtained are given and discussed.