Effects of Tetraethyl Lead on Catalyst Life and Efficiency in Customer Type Vehicle Operation 690016

Effects of four levels of tetraethyl lead (TEL) on the efficiency and life of a commercially available hydrocarbon and carbon monoxide catalyst were investigated. The four fuels used in mileage accumulation were the base Indolene with no added lead and blends containing respectively 0.5, 1.5, and 3.0 ml TEL/gal. The vehicles were eight Fords equipped with 289-CID non-emission-controlled 2-V engines unmodified, except for a lean carburetor and the catalytic exhaust system. The eight vehicles were paired off, and each pair was operated on one of the four fuel blends. In each pair, a radial flow converter, which required no supplemental air, was located under the front seat in one vehicle and near the rear axle in the other vehicle.

Exhaust emissions were monitored at approximately 3000-mile intervals during accumulation of 18,000 miles in customer-type service. TEL in the fuel adversely affected the rate of warm-up, the ability of the catalyst to remove hydrocarbons from the exhaust, and accentuated the differences in the performance between front and rear converters as mileage was accumulated. On nonleaded fuel, the catalyst performed well in preferentially removing olefins and aromatic hydrocarbons to yield an exhaust of very low reactivity, until problems were encountered with losses of catalyst. The catalyst removed CO, aliphatic aldehydes, and acetylenes equally well on leaded or nonleaded fuel.