Tests to determine the location under the hood of a motor vehicle where the air-intake of the carbureter will be exposed to the least dust were made by the agricultural engineering division of the University of California at Davis, Cal., and the results are given in the hope that they will serve a useful purpose. Of three types of dust-screen devised to catch the dust at different locations so that it could be photographed, and still would present little hindrance to passage of the air from point to point under the hood, the most effective was one of coarse hospital gauze stretched over frames set in transverse vertical positions on either side of and above the engine.
The tests were made on two phaetons and a speed truck, run for less than 3 miles and following another car on a dusty road. Photographs show the screens in position in the vehicles and removed to show the distribution of dust as collected under various operating conditions, as with the radiator fan idle and with it revolving with the fan-belt normally tight.
The conclusion reached as a result of the tests is that, in normal cases, the best carbureter-intake position would seem to be (a) on the side of the engine on which the fan-blades have a descending motion, (b) about midway between the radiator and the dash, (c) about midway between the side of the hood and the center line of the engine, and (d) about one-third of the distance down from the top of the hood toward the top of the cylinder-head.