A NEW, simple method, applicable in the laboratory or on the road, for detecting even mild preignition, is described in this paper. The method requires a small amount of inexpensive equipment, easily installed without mechanical modifications to the engine. The procedure is likewise simple, accurate, and will yield reproducible results. Mild preignition can be detected, regardless of the location of the source, and the results also clearly indicate the difference between preignition and detonation.
An oscilloscope is used to identify preignition; detonation is determined by its audible knock. With increase in compression ratios and power output necessitating study of these phenomena, it is expected that proper instrumentation for differentiating between the two will be extremely useful.