Mixture Distribution 300007

HOPING that discussion and dissemination of information on the fundamentals of distribution routine will continue, the author reiterates known facts, which include (a) the method of charting distribution progress, (b) a suggestion for locating the error in distribution and (c) a series of thoughts on construction. The paper is divided into two parts, the first being a study of distribution routine and the other a discussion of a few of the problems that are met every day in the search for perfect distribution.
Complete satisfactory distribution and the quantitative measurement of its quality are the two major problems of distribution. The interrelation of these problems is mentioned and the complexity of the subject of distribution is emphasized by listing nine detailed factors, the point being made that if the information that engineers have on these items could be collected and codified considerable progress would be made. Following this, the usual test procedure of runs for power, economy and friction is outlined, and the questions of efficiency based on air consumption, economy versus power, the maximum-economy point and car-driving loads are discussed, and the procedure to be followed in securing this information described.
The employment of preheated air or an externally heated T-manifold to heat the mixture is discussed and the conclusion is drawn that distribution of extremely lean mixtures is improved by the use of heated air. The author emphasizes the importance of using data to indicate where errors in distribution occur and comparing mixture fishhooks for a quantitative measurement.
In Part 2 consideration is given to the influence of the carbureter on distribution, throttle-plate deflection, balancing the airstream and the relation of manifold and valve size. The recommendation is made that the valve capacity that would give a high-speed range exceeding the requirements should be used and the top range limited to the required point by decreasing the area of the manifold. Precipitation and its control by the application of heat, the means employed to divide the wet fuel accurately and keeping the fuel in the airstream by correct design are mentioned and concrete examples given.
The discussion,* which was almost exclusively written contributions, emphasized the analytical value of the fishhooks, established a criterion for part-load efficiency, mentioned the use of separators to indicate the faults of the distribution by catching the unvaporized fuel, pointed out the effect of the direction in which the carbureter air-horn was turned on the richness of the air-fuel mixture, described the task of the carbureter engineer in adapting his design to an engine, presented data on air and fuel distribution and the application of heat and mentioned the possibility of using indicator diagrams to measure the relative filling of the several cylinders.


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