Abstract: A system for NOx reduction in combustion gases, especially from diesel engines, incorporates an oxidation catalyst to convert at least a portion of NO to NO2, a particulate filter, a source of reductant such as NH3 and an SCR catalyst. Considerable improvements in NOx conversion are observed.

Abstract: A system for NOx reduction in combustion gases, especially from diesel engines, incorporates an oxidation catalyst to convert at least a portion of NO to NO2, a particulate filter, a source of reductant such as NH3 and an SCR catalyst. Considerable improvements in NOx conversion are observed.

Abstract: An exhaust system for a vehicular lean-burn internal combustion engine includes a NOx reduction catalyst, a source reductant, means (20) for contacting the catalyst with the reductant, means for sensing the temperature of the exhaust gas and/or the catalyst bed and means, when in use, for controlling reductant addition. The reductant addition control means supplies an amount of reductant to the catalyst at a rate corresponding to a measured temperature value of the exhaust gas and/or catalyst bed, which temperature value has been pre-determined to correlate, in use, with an amount of NOx in the exhaust gas.

Abstract: A process for treating an exhaust gas on a lean-burn reciprocating internal combustion engine includes the steps of collecting particulate matter (PM) on a first filter and combusting a carbon fraction thereof, periodically reversing the direction of gas flow through the first filter thereby displacing uncombusted PM from the upstream side of the first filter and collecting at least part of the displaced PM on a second filter.

Abstract: A method of treating an exhaust gas of a lean-burn reciprocating engine includes sorbing NOx on at least one NOx sorber when the exhaust gas is lean, intermittently contacting the at least one NOx sorber with an agent effective to convert NOx to N2, thereby to regenerate the at least one NOx sorber and feeding effluent of said intermittent contacting step to the engine inlet.

Abstract: A system for NOx reduction in combustion gases, especially from diesel engines, incorporates an oxidation catalyst to convert at least a portion of NO to NO2, a particulate filter, a source of reductant such as NH3 and an SCR catalyst. Considerable improvements in NOx conversion are observed.

Abstract: Selective catalytic reduction of NOx in combustion gases, especially from diesel engines, utilizes a system incorporating an oxidation catalyst to convert at least a portion of NO to NO2, a particulate filter downstream of the oxidation catalyst, a source of reductant such as NH3 or urea for injection downstream of the particulate filter, and an SCR catalyst located downstream of the point of injection of the reductant. Considerable improvements in NOx conversion are observed.

Abstract: A heavy duty diesel engine having an exhaust system incorporating a catalyst to convert NO to NO2 and a particulate trap on which soot particles are continuously oxidized, and a portion of the exhaust gases are recirculated through a cooler and exhaust gas flow valve before being mixed with air and fed to the engine cylinders. The system also incorporates a sensor to detect the amount of NOx in the exhaust to adjust the gas flow valve, thereby adjusting the portion of recirculated exhaust gas fed to the engine cylinders.