Verfahren und eine Katalysatoreinheit zur Reduktion von Schadstoffen, insbesondere zur Reduktion von Stickoxiden in Abgasen von Verbrennungskraftmaschinen

摘要

A catalyst unit, especially one for reducing NOx in oxygen-containing exhausts, is one constructed to take advantage of non-Faraday electrochemical modification of catalytic activity ie where the activity is affected and so controllable by applied voltage. As shown, the unit 1 has a catalytic layer 5 and a counterelectrode 8, separated by an ion-conducting layer 6. A controllable voltage is applied by source 10. The layers and unit are constructed of materials stable in the exhaust gas, and the catalyst layer may be porous and have a noble metal catalyst. The voltage may be varied with the temperature and composition of the exhaust gas and also in response to engine speed or load. The reduction of NOx may be by reaction with hydrocarbons present in the exhaust. The ion-conducting layer may be connected to a supply 9 of ions. <IMAGE>