The oxidation of soot: a review of experiments, mechanisms and models

A particulate trap for diesel engine use which is less likely to vibrate or deform under exhaust pressures achieves goods results in particulate trapping properties, pressure drop, durability and regenerating properties. This trap has a filter element having a plurality of flat or cylindrical filters of three-dimensionally reticulated porous member. Longitudinally extending exhaust incoming and outgoing spaces are defined alternately between the adjacent filters by alternately closing the inlet and outlet ends of the spaces between the adjacent filters. Gas permeable reinforcing members are inserted in the exhaust outgoing spaces to prevent the filter from being deformed due to the difference between the pressure upstream and downstream of each filter produced when exhausts pass through the filters. Similar gas permeable reinforcing members may also be inserted in the exhaust incoming spaces or at both ends of the filter element to more positively prevent vibration of the filters.

Particulate trap for diesel engine

Provided is a catalyst article for simultaneously remediating the nitrogen oxides (NOx), particulate matter, and gaseous hydrocarbons present in diesel engine exhaust streams. The catalyst article has a soot filter coated with a material effective in the Selective Catalytic Reduction (SCR) of NOx by a reductant, e.g., ammonia.

Catalyzed scr filter and emission treatment system

An exhaust gas purification device having a NOx absorbent includes a by-pass passage for by-passing the NOx absorbent, an exhaust gas flow rate control portion for regulating both a flow rate of exhaust gas flowing to the NOx absorbent and the flow rate of the exhaust gas bypassing the NOx absorbent, and a reductant addition portion for adding reductant into an exhaust passage upstream of the NOx absorbent In this device, when it is necessary to discharge sulfur components from the NOx absorbent, a temperature rise control is executed such that a temperature of the NOx absorbent becomes higher than a predetermined temperature Next, a rich condition control is executed such that an air-fuel ratio of the exhaust gas flowing to the NOx absorbent becomes one of a substantially stoichiometric condition and a rich condition The flow rate of the exhaust gas to the NOx absorbent during the temperature rise control is controlled so as to be higher than that during the rich condition control

exhaust gas purification device

An exhaust gas aftertreatment installment and associated exhaust gas aftertreatment method utilizes a nitrogen oxide storage catalytic converter and an SCR catalytic converter. A particulate filter is provided upstream of the nitrogen oxide storage catalytic converter or between the latter and the SCR catalytic converter or downstream of the SCR catalytic converter. The time of regeneration operating phases of the nitrogen oxide storage catalytic converter can be determined as a function of the nitrogen oxide content of the exhaust gas downstream of the nitrogen oxide storage catalytic converter or of the SCR catalytic converter and/or as a function of the ammonia loading of the latter. Moreover, a desired ammonia generation quantity can be determined for a respective regeneration operating phase. The installation and method are adopted for use for motor vehicle internal combustion engines and other engines which are operated predominantly in lean-burn mode.

Exhaust Gas Aftertreatment Installation and Method

In a process wherein diesel exhaust gas is passed through a filter (3) to remove particulate therefrom before discharge and particulate deposited on the filter is combusted, the improvement which comprises combusting the particulate with a gas containing NO₂ which may be catalytically generated in the exhaust system (1).

Treatment of diesel exhaust gas

An SCR catalyst consisting essentially of iron sulfate or oxysulfur iron compound carried by a mixture of ceria and alumina on a support.

Selective catalytic reduction catalysts

A supported vanadium oxides/tungsten oxides catalyst, a process for using the same for the reduction of nitrogen oxide, and a process for preparing the same by impregnating a support with a tungsten solution followed by impregnating with a vanadium solution, calcining to convert tungsten and vanadium to oxides.

Vanadium/tungsten catalyst and process

An SCR catalyst consisting essentially of at least one oxysulfur compound of manganese, nickel or mixtures thereof, carried by a supported mixture of ceria and alumina. The catalyst is characterized by its high activity and by its stability even when used in the absence of sulfur oxides.

Selective catalytic reduction catalyst consisting essentially of nickel and/or manganese sulfate, ceria and alumina

PURPOSE: To combust particles at low temperature with a gas containing NO 2 by passing the diesel exhaust through a filter to remove the particles and combusting these particles collected by the filter. CONSTITUTION: Alumina wash coat carrying Pt catalyst is coated on the ceramic honeycomb monolith 1, a particle filter or a trap 3 for receiving the gas from the monolith 1 is connected to lower side of the monolith 1 through a connection passage 2. Low price metal catalyst, for example, catalyst absorbing sulfur or sulfate is kept on the surface of the filter 3. During use, the diesel exhaust gas flows from inlet 4 into the device, is treated there by the monolith 1, and NO 2 is generated from NO gas by catalyst reaction. The gas containing high content NO 2 is delivered to the filter 3 and the soot particles are combusted at 250 to 400°C. COPYRIGHT: (C)1989,JPO

Hyun Jong Jung

Papers

Treatment of diesel exhaust gas

Selective catalytic reduction catalysts

Vanadium/tungsten catalyst and process

Selective catalytic reduction catalyst consisting essentially of nickel and/or manganese sulfate, ceria and alumina

Treatment of diesel exhaust gases and apparatus therefor