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Light Duty Vehicle CO Emissions During Cold Weather
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Abstract
Recent tests conducted by the Alaska Department of Environmental Conservation and low ambient temperature tests previously conducted by a variety of other organizations indicate that less progress is being achieved in the control of emissions during cold weather than under temperatures similar to those used during EPA certification testing. Although CO emission standards dropped from 15 grams per mile to 7 grams per mile between 1975 and 1981, far less of a change occurred in CO emissions from new vehicles at 20°F. Cold start CO emissions at 20°F are about 60 grams per mile for late model cars at low mileages. The available test data on these cars seem to indicate that results achieved using the standard emission test procedure are poorly correlated with emissions at lower temperatures.
However, the low temperature CO emissions of cars certified at 3.4 grams per mile CO are nearly 502 lower than vehicles certified to a standard of 15 grams per mile. The benefits of the 3.4 gram CO standard on low temperature emission control appears to be due to the fact that manufacturers have been induced to use systems which are much more effective in reducing the degree of mixture enrichment needed during cold start operation.
Test data indicate that cold temperature emission performance from cars equipped with fuel injection systems are clearly superior to most carburetor equipped cars. However, comparable levels of low temperature CO control may be possible with carburetors through the use of electric intake manifold heating grids. Unless new regulations provide an alternative mechanism for encouraging the use of such systems, the achievement of the ambient air quality standard for CO in areas which experience violations during cold weather may depend on the continued requirement for a 3.4 gram per mile standard.
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Austin, T., Rubenstein, G., Verrelli, L., and Moyer, T., "Light Duty Vehicle CO Emissions During Cold Weather," SAE Technical Paper 831698, 1983, https://doi.org/10.4271/831698.Also In
References
- Norbeck J. Chang T. “An Analysis of Ambient CO Concentrations in Alaska,” Engineering and Research Staff, Ford Motor Company, (undated)
- Gilmore T. M. “Acceptability Survey for Cold Start Automobile Emissions Study.” Prepared for the Fairbanks North Star Borough May 1978
- Duckworth, S. et al. “Analysis of Meteorological and Other Factors Influencing Air Quality Trends,” California Air Resources Board 1980
- Hoyles M. Moyer T. “The Significance of Engine Warm-Up Time on Carbon Monoxide Emissions from Motor Vehicles,” Alaska Department of Environmental Conservation November 1981
- Service G. “CO Hot Spot Preliminary Investigation,” Report No. 77-13” Technology Assessment and Evaluation Branch, Emission Control Technology Division, Office of Mobile Source Air Pollution Control, U.S. Environmental Protection Agency December 1977
- Bruetsch R. “Carbon Monoxide and Non-FTP Ambient Temperature,” Report No. EPA/AA/CTAB/TA/81-7, Control Technology Assessment and Characterization Branch, Emission Control Technology Division, Office of Mobile Source Air Pollution Control, U.S. Environmental Protection Agency February 1981
- Branham R. “Evaluation of the Temperature Effects on Five 1981 Passenger Vehicles,” Report No. EPA-AA-TEB-82-4, Test and Evaluation Branch, Emission Control Technology Division, Office of Mobile Source Air Pollution Control, U.S. Environmental Protection Agency December 1981
- Murrell, J. et al., “Light Duty Automotive Fuel Economy… Trends thru 1983,” SAE Paper No. 830544 , February 1983
- Unpublished results from 1982-83 METFac testing program, Alaska Department of Environmental Conservation
- Austin T. Rubenstein G. “Estimated Emissions Benefits of Vehicle Inspection and Maintenance Programs in Alaska,” memo report to Alaska Department of Environmental Conservation July 1983
- Based on an analysis of the data contained in Figure 1 of reference 10