Tt E often said that the safest method of predicting the future is to examine the past and present. In the past, automotive engineers have taken advantage of constantly improving fuel quality by increasing the compression ratio with resultant increases in power per cubic inch displacement and power per gallon of fuel The improvement of the anti-knock quality of gasolene is a necessary part of this correlated development because the tendency of fuel to knock limits the ability of the spark ignition engine to convert the energy of fuel into power.
Research engineers, using an automobile equipped with a valve-in-head engine as a test vehicle, conducted a series of tests in the laboratory and on the road at a number of ce pression ratios end gear ratios. Fuels in each case were just capable of avoiding knock—approximately 69 octane for 5.25 compression ratio; 95 octane for 8.0 compression ratio, and something over 190 octane for 10.3 compression ratio. At 40 miles per hour the miles per gallon improved from 125 at 525 compression ratio to 18 at 8.0 and 21 at 103 The average increase in economy, between 10 and 60 miles per hour, is about 45 per cent, going from 5.25 to 8.0 compression ratio under conditions of constant performance.
It has been found that a relatively small increase in compression ratio in the engine of a heavy commercial vehicle made it possible under certain circumstances to haul heavier pay loads at increased speeds with less fuel consumption. The data has some practical applization at the present time, but its greatest importance lies in the fact that it points the way -9 even greater gains in the future.
Text read from the printed page and cleaned; old type leaves the occasional error.