DEVELOPMENT AND EVALUATION OF AUTOMOBILE EXHAUST CATALYTIC CONVERTER SYSTEMS 620397
For the past seven years, the Ford Motor Company has been working on the development of catalytic exhaust treating systems designed to minimize the emission of certain vehicle exhaust gas constituents. In 1959, the development of a low-temperature, catalytic-converter system for the oxidation of exhaust gas hydrocarbons was described in a paper presented to the SAE. That system, which used vanadium pentoxide as the catalyst, has since been extensively developed in a program that included 250,000 miles of converter evaluation on vehicles. Many of the basic system requirements and problems covered in those tests are relevant in vehicle applications of a catalytic converter system with any type of catalyst.
With the insertion of a carbon monoxide limit in the California Exhaust Standard, work on the low-temperature, catalytic converter system was discontinued since this system did not, and was not designed to, oxidize carbon monoxide. An engine-dynamometer catalyst screening procedure was developed and used to select catalysts capable of oxidizing both hydrocarbons and carbon monoxide for vehicle evaluation. Tests were made of catalysts submitted by outside suppliers, catalysts made by outside suppliers to Ford specifications, and catalysts made at the Ford Research Laboratories. From the results of the screening tests, three of the catalysts were accepted for vehicle tests.
Tests of vehicle systems employing catalysts selected from the screening tests showed the systems to be inadequate from the standpoint of the catalysts maintaining oxidation performance for extended mileage.
If a satisfactory catalyst can be found to improve the performance of the systems to an acceptable level, much work still remains to be done to develop an acceptable catalytic converter system for vehicles.