NOx Catalytic Converter Development

The ammonia forming characteristics of two NO_x catalysts have been thoroughly studied under steady-state conditions after defining the ranges of such parameters as intake air flow, inlet gas temperature, Inlet exhaust emissions and inlet CO/O₂ under the CVS-III (hot) mode.

A four-cylinder 1.6 liter engine equipped with a dual-bed catalytic converter system was used. Two catalysts having the same catalytic materials and loadings were prepared on pelleted and monolithic supports. The test results show how and why the bleed air, added ahead of the NO_x catalyst, is effective in reducing ammonia formation and improving the net NO_x reduction efficiency of the system.