A SGB has been designed and developed to study the reduction of O₂ content of exhaust emissions from heavy duty diesel engined vehicles. Inlet gas mixture simulates the emission concentration of a diesel engine. This SGB of the ORS provides the ability to validate O₂ reduction under various temperatures (300-750^oC), humidity and inlet gas mixture concentration conditions. The inlet mixture is regulated by utilization of flow meters and the mixture is directed into the reactor. A gas chromatograph (GC) was used for outlet gas analysis.