The Development of a Catalytic Converter for the Oxidation of Exhaust Hydrocarbons 590225

The development of a catalytic converter system for oxidizing exhaust hydrocarbons is presented. Also presented are possible solutions to several mechanical problems associated with catalytic converters such as introduction of secondary air, excessive exhaust system back pressure, attrition loss of catalyst material, and exhaust system noise.

Data are presented on the efficiency of vanadium pentoxide catalyst in the Ford catalytic converter system. Overall operating efficiencies of 6-3% can be expected in the removal of exhaust hydrocarbons. During tests with the converter in a smog chamber, average hydrocarbon conversion efficiencies of 88 and 91% respectively were achieved for idle and deceleration, and efficiencies of 68 and 74% respectively were achieved for acceleration and cruise. For the catalytic converter system described, minimum warm-up time has been achieved, and with a converter only slightly larger than a standard muffler, catalyst durability of over 10,000 miles has been reached. Since a low-temperature catalyst is used, expensive stainless steel is not required in the construction of the converter.

In smog chamber tests eye irritation was created by detuning the engine and using a disproportionate sample of deceleration exhaust. When the Ford catalytic converter was then used under the same conditions, no eye irritation was experienced.

Among those problems yet to be solved are the elimination of occasional unpleasant odors, and the improvement of catalyst durability and efficiency.