ONCE a method for standard Diesel-fuel knock-rating has been established, a standard for Diesel-fuel specifications should be set which will cover standard knock-rating, gravity, viscosity, pour point, Conradson carbon, water, sediment and sulphur content. The last three items have an important influence on the wear and depreciation of the engine as well as on the carbon formation in the combustion chamber.
The foregoing conclusions are reached after the author has treated the subject in general as well as in particular, under the headings: Combustion process, delay period, turbulence, drop-size, variable delay-time, spontaneous and controlled combustion, chemical characteristics of the fuel and physical properties. Practical methods for oil-engine-fuel knock-ratings are also suggested.