17 March 1999

The Manufacturers of Emission Controls Association (MECA) released a report entitled "The Impact of Sulfur in Diesel Fuel on Catalyst Emission Control Technology" which concludes that reducing the level of sulfur in diesel fuel will allow the introduction in the United States of several promising control technologies to reduce oxides of nitrogen (NOx) and particulate matter (PM) from diesel engines.

The report states that the current diesel sulfur levels (500 ppm for on-road vehicles and higher for off-road engines) are a major barrier to the introduction of such technologies as NOx adsorbers and lean NOx catalysts, which have demonstrated the potential to control greater than 50% of the engine-out NOx emissions. These high sulfur fuels also preclude the use of attractive and commercially available PM filter system that uses a NOx catalyst to facilitate the destruction of the diesel particulate (so called CRT trap). Lower sulfur fuel further enhances the performance of other PM and HC control technologies, such as oxidation catalysts and catalyzed diesel particulate filters, which can operate on current diesel fuels.

The report notes that current research and development efforts indicate that sulfur levels below 30 ppm likely will be required to enable the full range of promising exhaust control technologies to be introduced and fully optimized for maximum emission control performance.

Bruce Bertelsen, executive director of MECA, stated, "We believe the goal of a truly clean and environmentally friendly diesel engine is achievable. But meeting this goal will take considerable effort and will require a systems approach utilizing the most advanced engine designs, advanced and integrated exhaust control technologies, and low sulfur diesel fuel."

The report can be downloaded form the MECA web site (256k pdf).

Contact: Bruce Bertelsen, MECA, 202/296-4797
Source: MECA