TESTS conducted to determine how air-fuel ratios obtained by analyzing the exhaust gases checked with ratios obtained by measuring the air and fuel are analyzed by the author, the tests having been made on a six-cylinder 3½ x 5-in. engine and the air measured by using a Durley air-box having a 2-in. flat-plate orifice. As a check, a 1½-in. well-rounded orifice was also used with the same results. The exhaust gases were analyzed in conventional Orsat apparatus having four absorption bottles. The tests were made at a constant air-fuel ratio at an engine speed of about 1300 r.p.m. with a wide-open throttle and maximum-power carbureter-setting. Thus far, 31 samples have been taken by different men and the air and fuel were measured each time a sample was taken. Three methods of obtaining air-fuel ratios from the exhaust-gas analyses were used and compared, and the author comments upon the results obtained.
In the discussion following the paper, checking-up tests on the accuracy of air-fuel ratios determined by exhaust-gas analysis are summarized, and a subsequent statement is made by the author that the tests he made were conducted to ascertain how reliable the simple method described in his paper is.