Apparatus and Method for Rating Motor Fuels in the Order of Detonation 270004
AS the title indicates, this paper comprises a description of the construction of an apparatus and the development of a method of operating it in determining the rating of motor fuels in the order of their detonation. A Delco-light unit, consisting of a single-cylinder internal-combustion engine directly connected to a direct-current generator, was the basic outfit used but it was changed in many ways in its course of development as a testing-machine. The changes made are explained in detail. The method of testing adopted for rating a motor fuel was to match it, by trial and error, with a blend of chemically pure benzene and selected straight-run Pennsylvania gasoline. Several series of experiments were made to determine what blend or blends of benzene and the standard gasoline match a given fuel under widely different conditions of compression-ratio and spark-setting. The author hopes to standardize these blends later in terms of pure heptane and pure octane, as has been proposed by Dr. Graham Edgar. The results obtained in the experiments are presented in an easily understood series of charts.