Pages: 2 Published: Jan 1958
The data presented in this book have been prepared with the objective of assembling in one publication antiknock values of a wide range of pure hydrocarbons. The values in the tables represent the most complete and accurate comparable data on the knocking characteristics of pure hydrocarbons in existence. However, a word of caution in using these data as absolute values is necessary because of the empirical nature of the values and the knocking peculiarities of the hydrocarbons themselves. So often the question is asked, “What is the antiknock value of a given hydrocarbon, and what relationship exists, if any, between its structure and one of a different configuration?” The greatest use of the values presented here has been in the development of correlations between the molecular structure of the hydrocarbons and their knocking characteristics. Many of these correlations are given in another section of this book. They may be used to better understand the chemical reactions leading to the phenomenon of knock, to suggest chemical refining processes which may lead to fuels of desirable knocking properties, and to predict the knock ratings of new and untested hydrocarbons. The data are also an invaluable aid in the planning of future test programs involving the use of pure hydrocarbons. The knock ratings of these pure hydrocarbons cannot be used at present to predict with any degree of accuracy the knock ratings of mixtures of hydrocarbons since the knocking characteristics of a hydrocarbon in mixtures, as discussed later, are dependent on the base fuel or mixture of which it is a part, on its concentration, and on engine operating conditions.
Paper ID: STP47002S