AUDIBILITY ANTI-KNOCK TESTS AND KNOCK-INTENSITY EVALUATION 260030
Valuable data pertaining to the anti-knock qualities of fuels, combustion-chamber shapes and the efficiency of gasoline dopes are believed to be obtainable by the method described. Several hundred tests have failed to show anything seriously wrong with the method; on the contrary, involved matters such as the relative effect of various anti-knock fuels, anti-knock dopes, altitude, compression, mixture-ratio, and cylinder actions, have become clearer. No apparent reason exists why the method is not applicable to the determination of the relative merits of combustion-chamber shapes, various spark-plug locations and other important considerations necessary to the realization of higher compression-pressure and its accompanying substantial fuel-saving. Further, the incidental information gained concerning engines of present-day compressions is of no small value.
As an example of its application, the method has been used to appraise the value of anti-knock dopes or fuels, and to determine the quantities necessary to produce equivalent anti-knock results. Evidently, the proportional blends can be determined conclusively. Refining processes can be surveyed from the anti-knock viewpoint and the data used as aids in the writing of refinery control-specifications. Inspections by this method of many proposed anti-knock dopes have shown their effectiveness or ineffectiveness. Apparently, the method is applicable either to knock-suppressers or to knock-inducers, as shown by the several knock-suppressing tests and the normal butyl nitrite knock-inducer test. In the method as used, the effect of the personal equation is more imaginary than real. A certain technique is necessary, but check results are repeatedly obtained with unknown fuels and indiscriminate change-overs of the testing engineer during the series of test runs on any fuel have been made by Prof.
H. S. White3 and the author with the same results as though the test were completed by one engineer. It is stated by the author that the purpose of the paper will be fulfilled if the limitations as well as the advantages of the test-method are brought out by the discussion.