1939-01-01

Spark Timing - Its Relation to Road Octane Numbers and Performance 390148

MEASUREMENTS in the authors' laboratory have shown that the differences between the power that is obtained with present spark timings and that which could be obtained at maximum power spark timing do not differ greatly among cars, and are of the order of 1 to 2%.
As a future program, the authors recommend investigation of how the shape and slope of the highest useful spark-advance curve is influenced by fuel characteristics, engine design, and by the conditions under which the engine is operated, and of how it can be fitted to the maximum-power spark-advance curve.
Such work, they believe, will go a long way toward solving the riddle of the excessive variability of road octane numbers; it will allow the engine designer to fit his engine to the fuels now available without complicated gadgets.

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