Exhaust gas catalyst.

摘要

An exhaust gas catalyst for treatment of exhaust gases developed by burning a hydrocarbon fuel or a fuel containing hydrocarbon and alcohol blends in an internal combustion engine comprises a support having deposited thereon palladium and finely divided tungsten. The palladium/tungsten combination is effective in the catalytic oxidation of unburned hydrocarbons and carbon monoxide and the catalytic reduction of oxides of nitrogen without production of significant amounts of ammonia when the internal combustion engine is operating under fuel rich conditions. In one embodiment the palladium and tungsten are both distributed over the whole of the support; in another embodiment the palladium is distributed over the whole of the support and the tungsten only over a downstream portion thereof; in a third embodiment the palladium is distributed over an upstream portion of the support and the tungsten over a downstream portion thereof.