Catalytic converters will be required in some future truck exhaust systems because of recently enacted emission standards. A computer model was developed to evaluate means to cool the exhaust to protect the converters to improve their durability. The model showed that changing the pipe diameter or wall thickness had little effect on exhaust cooling. Adding internal ribbing or exterior fins improved the exhaust cooling by only a few degrees C. Counterflow air-cooling was not found to be effective, but counterflow water-cooling was able to cool the muffler-out exhaust gas below the target temperature £or all test conditions.
