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The problem associated with laboratory evaluation of muffler acoustical characteristics are complicated both by the acoustical considerations involved in obtaining an adequate noise source and by the ambiguities involved in defining what constitutes quality in a muffler built for general application. In order to quantitatively define the characteristics of quality mufflers, an extensive series of field tests were conducted on a variety of sizes and types of mufflers in conjunction with four engine configurations. Work then turned to the development of a wide band siren noise source and acoustical test system which would simulate the high impedance character of an engine exhaust noise source, and in addition generate the necessary intensity and spectral characteristics required to obtain test data over the range of noise conditions encountered in the field.

This paper presents the results of an investigation of the normal sources of hydrocarbon emissions of passenger cars. The sources were considered to consist of the crankcase ventilation and exhaust systems, the carburetor, and the fuel tank vent. Many studies involving the emissions from several of these sources have been conducted and reported; however, it is believed that this is the first study designed to develop emission data from all the sources of a single group of passenger cars. Although only five vehicles were used, several mechanical conditions and engine and power train configurations were examined. The largest single source of hydrocarbon emissions was found to be the exhaust, followed by the road draft tube. Relatively minor emissions were measured as a result of fuel evaporation from the carburetor and fuel tank during periods of operation and hot soak.

This paper discusses the experimental work that produced a revised military standard piston ring (conformable steel-rail oil control ring) with improved oil consumption and wear characteristics. The testing of these parameters was accelerated by the use of radio-tracer techniques. The effects of variables such as engine speed, load, jacket temperature, air-fuel ratio, intermittent starts and stops, and cyclic load operation is described. Performance characteristics of the present standard and experimental piston rings are included.