A review of experimental studies of knock chemistry in engines

Early engine research related to the chemistry of knock produced results which complement and support modern work and, in many cases, provide intriguing data against which modern concepts and models of knock can be compared. This article presents a chronological summary of research in motored and fired engines conducted to understand the chemical processes associated with knock. Further, it attempts to highlight the superior and intriguing aspects of these works. Four basic research areas are covered: fuel effects, including fuel structure, additives and pre-oxidation, pre-combustion heat release, spectroscopic investigations and rapid sampling valve research.