| 摘要 |
An efficient method and an apparatus are provided to reduce selectively NOx in an exhaust gas feedstream in automobiles and other applications of lean-burn internal combustion engines. An exhaust gas post-treatment system for an internal combustion engine(10) comprises: a catalytic reaction device comprising silver; an injection device(16) operated to inject a hydrocarbon reductant into an exhaust gas feedstream upstream of the catalytic reaction device; and a control system adapted to determine a parametric measurement of NOx gases in the exhaust gas feedstream, determine a preferred hydrocarbon/NOx ratio, and control the injection device such that the hydrocarbon reductant is optionally injected into the exhaust gas feedstream during the lean operation of the internal combustion engine. The silver of the catalytic reaction device comprises silver-alumina. The hydrocarbon reductant comprises an engine fuel. The control system adapted to determine a parametric measurement of NOx gases in the exhaust gas feedstream comprises a control system adapted to determine the parametric measurement of the NOx gases based on engine operating conditions. The control system adapted to determine a parametric measurement of NOx gases in the exhaust gas feedstream comprises a control system adapted to monitor an ON-input signal from a NOx sensor(12) operated to monitor the exhaust gas feedstream. The exhaust gas post-treatment system further comprises an oxidation catalyst(14) upstream of the injection device and the catalytic reaction device. The exhaust gas post-treatment system further comprises a plasma ozone generator upstream of the injection device and the catalytic reaction device. The exhaust gas post-treatment system further comprises one of an oxidation catalyst, a diesel particulate filter, an air pump inlet, an external heating device, a sulfur trap, a phosphorous trap, and a selective reduction device.
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