Economic Fuel-Volatility and Engine Acceleration 290027
THIS PAPER is a continuation of one presented at the 1928 Semi-Annual Meeting and gives the results of tests made to determine the effect of the A.S.T.M. 50-per cent point on acceleration and on the most economical fuel-volatility from the standpoint of acceleration.
Test made in connection with the first investigation were on three special fuels and covered a range of manifold temperatures representing the extremes of winter warming-up and summer-operating temperatures. These tests showed a consistent variation in the relative accelerations as the manifold temperature was varied and that the effect on engine acceleration of increasing the A.S.T.M. 50-per cent point volatility is negligbile under most conditions except those under which a car is operated in the summer.
In the second series of tests the objective was the quantity of each of the four special fuels that would give the same acceleration as United States Motor gasoline at an air-fuel ratio of 11.5 to 1. The operating conditions were chosen to give the maximum differences between the fuels used. Data are presented on the relative fuel-flows and approximate estimates of the relative yields from some average crudes.
From the data on relative fuel-flows, it is concluded that the effect of the A.S.T.M. 50-per cent point on the quantity of fuel required to give a stated acceleration appears to be negligible, except under summer-operating conditions. No conclusions are drawn at present from the estimated yields.