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U.S. Department of Energy
Office of Scientific and Technical Information

Exhaust emissions from 2-stroke outboard motors and their impact

Conference ·
OSTI ID:7157170

To characterize the exhaust emissions from water-cooled 2-stroke outboard motors, four new motors were tested on dynamometer stands. The engines ranged from 4 to 65 hp in size, and operating conditions were chosen along lines of simulated boat loading. All the measurements were taken at steady-state conditions. Emissions were measured in the raw exhaust gas and after the gases had been bubbled through water in a specially constructed tank. Constituents measured included hydrocarbons, carbon monoxide, carbon dioxide, nitric oxide, nitrogen oxides, oxygen, light hydrocarbons, and aldehydes. Emissions of sulfur oxides were estimated on the basis of fuel consumed. All the exhaust emissions data were used with available information on population and usage of motors to estimate exhaust emission factors and national exhaust emissions impact. The study did not address the fate of pollutants in either air or water as a function of residence time, nor did it include any assessment of environmental effects due to outboard emissions. As percentages of revised 1970 national air pollutants from all sources, outboard atmospheric emissions account for about 1 percent of HC, 0.9 percent of CO, 0.008 percent of NO/sub x/, and 0.004 percent of SO/sub x/. Expressed as percentages of revised 1970 totals for mobile sources only, outboards account for about 2 percent of HC, 1 percent of CO, 0.02 percent of NO/sub x/, and 0.1 percent of SO/sub x/.

OSTI ID:
7157170
Country of Publication:
United States
Language:
English