PRECOMBUSTION REACTIONS IN A MOTORED ENGINE

THE work reported in this paper is the first phase of a general project on end-gas reaction studies having as its broad objective the development of new information on the chemical factors causing knock.

This investigation has shown that the manifestations of precombustion reactions are affected by chemical and physical variables in much the same manner as these variables affect knock in a fired engine.

It has also been found that the temperatures and pressures required for trace knock in a fired engine are approximately the same as the conditions required for autoignition in a motored engine operated at the same speed, indicating that the precombustion reactions that lead to autoignition in the motored engine are probably the same as those that lead to knock in a fired engine.