The authors outline some of the problems that confront the automobile engineer today, showing how the demand for better performance and economy and the ever-increasing cost of volatile fuels has emphasized the necessity for thorough engineering work in the successful automobile manufacturing plant. Believing that the accurate analysis of the heat distribution in a modern automobile engine will be of great value, the authors describe a comprehensive test, made under their direction, of such an engine.
This test includes measurements of the brake horsepower, friction horsepower, fuel consumption and heat losses to jackets, exhaust and cooling air. The engine tested was inclosed in a hood, similar to that used on the car in normal service and an air blast was directed through this hood at speeds approximating those at which the engine would drive a car with a given gear ratio.
The authors analyze the results of the test, emphasizing the small percentage of the total heat supplied that is converted into useful work, especially at the light loads. This fact is made the basis for conclusions that suggest a consideration of means for decreasing heat losses. The possible application of Diesel and other constant-pressure cycles is mentioned, as are also certain modifications in the Otto cycle.