The paper is a progress report supplementing a previous report made by R. E. Carlson on the same subject and covers further investigations made by the Bureau of Standards to secure data that can be used as a basis for estimating the effect of a change in the gasoline volatility on the fuel-consumption of cars now in service throughout the United States. Actual tests began in August, 1922, to determine the effect of four fuels of different characteristics on the number of car-miles obtainable per gallon of fuel, as well as on the crankcase-oil dilution. The earlier paper discussed tests run in summer time. The present paper treats those run under winter conditions. Observations also were made on an engine which was set-up and operated in the laboratory under test conditions.
Descriptions are given of the fuels used, the test-cars, the apparatus, the tests and the test methods. The paper also covers a continuation of the crankcase-oil-dilution investigation, with appropriate accompanying data. The results are discussed briefly.