CLEAN EMMISSIONS
Article Date: 2-27-2003

New Method and Device Eliminate One of Three Main Pollutants in Exhaust Fumes

Werner H. Stemer and Laurence A. Greenberg with the law firm Lerner & Greenberg, P.A. have successfully obtained patents from the United States Patent and Trademark Office for a method and device that clean exhaust fumes from internal combustion engines (Patent numbers 6,516,610 and 6,516,607.)

The process reduces nitrogen oxide, one of three main pollutants in gas and diesel engines. Stemer, senior attorney at Lerner & Greenberg, said the concentration of nitrogen oxides is higher when the engine is operating in an optimal fuel consumption mode because the air to fuel mixture produces more of that gas.

While this type of gas is regulated in the United States and Europe, Stemer said, the legal limits cannot be achieved solely by improving the way the engine burns the fuel. That is why automobiles have catalytic converters. But while catalytic converters help reduce hydrocarbons, especially in gasoline engines, they don't reduce nitrogen oxide.

            "In gasoline engines with mixtures having higher air than fuel content and, in general, in diesel engines, the nitrogen oxide fraction cannot be converted without additional measures," Stemer said.

            Hence, that is the importance of a cleaning process such as the one patented by the attorneys.

            In the method and device, invented by Rolf Brück and Wolfgang Maus of the company Emitec Emissionstechnologie of Germany, liquid ammonia is injected into the exhaust fumes through a system that uses sensors to determine the amount of ammonia needed. The ammonia bonds to the nitrogen oxide before arriving at the catalytic converter. Mixed in this manner, all the components of the exhaust fumes can be better processed by the converter.

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