EARLY COMBUSTION REACTIONS IN ENGINE OPERATION 520249
IN this paper the authors present results of their study of precombustion reactions - which are chemical changes occurring in the fuel-air mixture ahead of the flame front - based on thermodynamic analysis of engine data. A single-cylinder, knock-test engine, operated at a fixed compression ratio, was used in conjunction with balanced pressure equipment for obtaining experimental data.
The thermodynamic analysis showed that simplification in computation of the heat of precombustion reactions would be possible if ignition timing were retarded, so that the normal flame would be initiated after completion of the precombustion reaction. Therefore, tests were run both at normal ignition timing and with retarded spark.
Another series of tests were made to determine the effects of precombustion reactions on the power developed by the engine.