SINCE the design of the automobile engine depends largely upon the volatility and knock rating of the gasoline fuel it uses, a major problem is the fitting of the engine to these two fuel-characteristics.
Regarding volatility, the engine must take the best advantage of the present available fuels; its design cannot be entirely made to suit an average gasoline; and, once an engine has been built, it must operate and give satisfactory service over a considerable period of years.
Recent trends in important items of design are noted, as well as the trends to automatic chokes and warm-up controls.
The author states that a system of classifying gasolines in terms of volatility is needed, and discusses various aspects of the starting problem. Other features include comments upon the trends in mixture temperatures, acceleration, crankcase dilution, and vapor lock.
The conclusion reached is that changes will continue to be made in fuels and in cars; hence, there is need for fitting fuels to engines and engines to fuels to the best advantage of the user, especially because the automobile manufacturer and the gasoline producer are trying to please the same people.