Technical Paper
Predicted Cold Start Emission Reductions Resulting from Exhaust Thermal Energy Conservation to Quicken Catalytic Converter Lightoff
1993-04-01
931087
Catalytic converters are a primary component of an automotive emissions control system used to control exhaust emissions to the low levels required by current regulations. During cold starts, the converter is ineffective until it reaches a lightoff temperature of approximately 3500 C. During this time 50% to 80% of the regulated hydrocarbon and carbon monoxide emissions are emitted from the tailpipe. To reduce these cold start emissions to meet the more stringent emission standards required by the Revised Clean Air Act of 1990 and the more restrictive California emissions standards, the catalytic converter must be heated quickly to lightoff temperature. Conservation of exhaust thermal energy is one of several approaches being studied to quicken lightoff. Much thermal energy is available in the gases leaving the combustion chamber with temperatures exceeding 350°C following engine ignition.
