IDEAL AND COMMERCIAL CARBURETER CHARACTERISTICS

Since previous papers by the author on this subject have dealt with the engine mixture-requirements at some length and these requirements are available to the public, only general information is included in the first part of this paper to illustrate the ideal carbureter-mixture requirements when using a fully developed acceleration device. In the second part, computed data illustrate the car carburetion-requirements of various cars for level-road operation. The car-test data were procured from various sources and combined with research results obtained in the Purdue University Engineering Experiment Station to delineate the factors desired. The results show the information regarding the advisability of using straight-line mixtures.

The third part constitutes the main section of the paper, and especial attention is called to it. Data are presented on commercial carbureters, the results of tests made on 23 carbureters are shown in detail, and a summary of the characteristics of the different devices is included for the general conclusions. The test results consist of information on the effect of pulsations on metering characteristics, on frictional loss across carbureter bodies and on the effect of air temperatures on metering. Using the methods of computation by which the data in the second part of the paper were determined, the results are expressed in terms of ideal mileage per gallon of fuel for various cars that are assembled into four classes. Using the same methods, the carbureter results were computed to show the economy any one device would effect in car operation and, in the fourth part of the paper, 11 devices are thus compared with the ideal carbureter at various car speeds.