The author selects and sets forth some of the main laws and basic considerations influencing carbureter action. A brief defense of the carbureter as a means of supplying fuel to an engine is made, as compared with the fuel-injection method, and conditions in the cylinder, the manifold and the carbureter during normal operation are stated. The relations of throttle positions, manifold vacuum and engine torque are discussed, followed by an exposition of the effect of manifold vacuum upon vaporization.
The subject of air-flow in carbureters is treated at some length and the venturi-tube form of air-passage is commented upon in considerable detail. The flow of air through air-valves, fuel-flow and mixture-proportion requirements are given detailed consideration, the last being inclusive of passenger-car, motor-truck, tractor, motorboat and airplane needs. The essentials for obtaining accurate information with regard to carbureter and engine tests are outlined. Drawings and charts supplement the text.