Since the detonation tendency of the fuel is the limiting factor in the development of power and the efficiency with which the fuel can be burned, the author considers this phase of the subject with the idea of laying down the principles on which better economy can be attained through higher compression. The subject is discussed in regard to the causes of detonation and the methods of controlling them because detonation limits the compression at which an engine can run.
The phenomenon of detonation is analyzed, the author's opinion being that increasing the temperature causes an increasing frequency of radiant-energy impulses and that, finally, it reaches a point where the frequency corresponds with the critical rate of the electrons that bind the elements together; thus, it breaks them asunder and then the velocity attains the highest rate possible in a gas of that density and temperature.
The causes of detonation are enumerated and the methods of control are explained, consideration being given also to hot-spots, cooling difficulties and turbulence as controlling factors. A statement is made of the actual compression pressures attained without detonation in road tests, and charts showing the horse-power developed and the fuel consumption are presented.