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The two year design-development program for the sonic carburetor is reviewed. Use of the sonic nozzle as an air flow meter, and the design criteria to achieve low unchoke points is discussed. The relation between sonic flow and improved fuel atomization and A/F ratio distribution to the engine is also discussed. Unchoke data and A/F distribution data are presented, and the tradeoffs between low unchoke points and good A/F distribution are explained. Conclusions are drawn relative to the overall benefits of the sonic carburetor.

An investigation of transient A/F characteristics was conducted using a 1.6 liter engine equipped with a Sequential Electronic Fuel Injection (SEFI) system. The engine was tested on a dynamometer facility capable of providing environmental temperatures as low as 10°F. A test procedure was developed to determine the effects of steady state A/F, engine speed, size of throttle ramp, injection timing, and hardware changes, on the transient A/F characteristics while the engine warmed up. It was found that, under cold operating conditions, the A/F excursions for the SEFI system were similar to those previously measured for a Central Fuel Injection (CFI) system on the same engine. It was also found that the sensitivity of the A/F excursions to variations in the test parameters, while quite dramatic at reduced temperatures, decreased as the engine warmed up.