METHOD FOR REDUCING EMISSIONS OF NOx AND PARTICULATES FROM A DIESEL ENGINE

摘要

A method improves the operation of a diesel engine (10) through the use of a fluel additive in container (50), a diesel particulate trap (20) and an NOx-reducing catalyst in chamber (30). The operation of the NOx-reducing catalyst is enhanced by the introduction of urea or like compound upstream in mixing device (60) of the catalyst at temperatures effective for non-catalytic NOx reduction and the generation of ammonia. The additive comprises fuel-soluble compositions of platinum group metal in effective amounts to lower the emissions of unburned hydrocarbons and carbon monoxide form the trap. The catalytic activity provided to the exhaust system (20 and 30) by the fuel additive is selective and preferably reduces the oxidation of SO2 to SO3. The platinum group metal compositions are preferably added in amounts effective to provide concentrations of the metal in the fuel in fuel tank (40) of less than 1 part per million (ppm). Lithium and/or sodium compositions can be used in amounts effective to reduce the trap regeneration temperature, e.g. concentrations to provide about 1 to 100 ppm lithium metal, and/or 1 tp 30 ppm sodium metal.