摘要:
Described is a method for cleaning the exhaust gases of internal combustion engines, which method is suitable for reducing harmful gases and particle emissions. Here, the exhaust gas to be cleaned is conducted, under operating conditions, with a discontinuous profile of the air ratio λ across a wall-flow filter substrate which comprises a catalytically active coating containing one storage material. The storage material is suitable for temporarily storing one or more exhaust-gas components under certain operating conditions and releasing said exhaust-gas components again in a targeted fashion in the event of a suitable change in the operating conditions. The coating is configured such that the component has a gradient of the storage material concentration and/or of the total coating amount, with the highest concentration of the storage material in the longitudinal direction of the component being present on the inflow side. At least 60% by weight of the storage material in relation to its total amount is present in the walls between inflow and outflow ducts, and at least 50% by weight of the storage material in relation to its total amount is present in a first, inflow-side zone in the wall-flow filter substrate.
摘要:
Described is a method for cleaning the exhaust gases of internal combustion engines, which method is suitable for reducing harmful gases and particle emissions. Here, the exhaust gas to be cleaned is conducted, under operating conditions, with a discontinuous profile of the air ratio λ across a wall-flow filter substrate which comprises a catalytically active coating containing one storage material. The storage material is suitable for temporarily storing one or more exhaust-gas components under certain operating conditions and releasing said exhaust-gas components again in a targeted fashion in the event of a suitable change in the operating conditions. The coating is configured such that the component has a gradient of the storage material concentration and/or of the total coating amount, with the highest concentration of the storage material in the longitudinal direction of the component being present on the inflow side. At least 60% by weight of the storage material in relation to its total amount is present in the walls between inflow and outflow ducts, and at least 50% by weight of the storage material in relation to its total amount is present in a first, inflow-side zone in the wall-flow filter substrate.
摘要:
Proposed is a diesel particle filter which comprises a ceramic wall-flow filter substrate and a coating applied in the inflow ducts, which coating is composed of material with a high melting point. The coating (6) is provided such that, by means of said coating, pores (5), which connect the inflow ducts (1) and outflow ducts (2), in the wall (4) are closed off for the soot particles (7) at the inflow side without said coating thereby preventing the passage of the gaseous exhaust-gas constituents. The coating may be produced from one or more oxides with a high melting point or from fibrous material with a high melting point. In both cases, the coating has the effect that the depth filtration is considerably reduced, and therefore the back pressure increase encountered during the depth filtration phase is significantly reduced.
摘要:
An SCR-catalytically active diesel particle filter having a ceramic wall flow filter substrate with inflow channels, outflow channels, walls separating the inflow and outflow channels, and two coatings. The first coating is applied in inflow channels, is composed of high-melting point materials, and closes the inflow sides of pores in walls connecting the inflow channels and outflow channels to soot particles without preventing passage of gaseous exhaust gas constituents. The second coating is within the walls between inflow channels and outflow channels, and effectively catalyzes the selective reduction of nitrogen oxides when in the presence of a reducing agent. The particle filter displays excellent banking-up pressure properties combined with high filtration efficiency and good regeneration properties; and displays good aging stability of NOx conversion activity.
摘要:
To equip a diesel particle filter with a zeolite-containing coating uniformly over the entire length of the particle filter and with a further zeolite-free coating which is applied, from the entry side of the filter, solely up to a specific length of the filter, it is proposed, first, to apply the zeolite-free coating from the entry side of the filter and only thereafter to apply the zeolite-containing coating over the entire length of the filter from the exit side of the filter. As a result of this sequence of coatings, a better adhesive strength of the coatings than when both coatings are applied from the entry side is ensured.
摘要:
To equip a diesel particle filter with a zeolite-containing coating uniformly over the entire length of the particle filter and with a further zeolite-free coating which is applied, from the entry side of the filter, solely up to a specific length of the filter, it is proposed, first, to apply the zeolite-free coating from the entry side of the filter and only thereafter to apply the zeolite-containing coating over the entire length of the filter from the exit side of the filter. As a result of this sequence of coatings, a better adhesive strength of the coatings than when both coatings are applied from the entry side is ensured.
摘要:
The invention relates to a catalytically active particulate filter which, in addition to the properties typical of particulate filters, has hydrogen sulphide block function, and to a process for removing nitrogen oxides and particulates from the exhaust gas of internal combustion engines operated predominantly under lean conditions (so-called “lean-burn engines”) using the inventive catalytically active particulate filter. This particulate filter comprises a filter body, a copper compound and an oxidation-catalytic active coating which comprises at least one catalytically active platinum group metal. The copper compound is in a second coating applied to the filter body. The two functional coatings may be applied to the filter body consecutive in the direction of flow, i.e. zoned, or layered one on top of the other.
摘要:
Proposed is a diesel particle filter which comprises a ceramic wall-flow filter substrate and a coating applied in the inflow ducts, which coating is composed of material with a high melting point. The coating (6) is provided such that, by means of said coating, pores (5), which connect the inflow ducts (1) and outflow ducts (2), in the wall (4) are closed off for the soot particles (7) at the inflow side without said coating thereby preventing the passage of the gaseous exhaust-gas constituents. The coating may be produced from one or more oxides with a high melting point or from fibrous material with a high melting point. In both cases, the coating has the effect that the depth filtration is considerably reduced, and therefore the back pressure increase encountered during the depth filtration phase is significantly reduced.
摘要:
A diesel particle filter which comprises a ceramic wall flow filter substrate and two coatings is described. The first coating which is applied in the inflow channels and is composed of high-melting materials has such a nature that it closes the inflow channels and pores in the wall connecting the inflow channels and outflow channels to soot particles on the inflow side without preventing passage of the gaseous exhaust gas constituents. The second coating is introduced into the wall between inflow channels and outflow channels and is of such a nature that it can effectively catalyze the selective reduction of nitrogen oxides by means of a reducing agent. The resulting component is an SCR-catalytically active particle filter and displays excellent banking-up pressure properties combined with high filtration efficiency and good regeneration properties. Furthermore, the component displays good aging stability of the NOx conversion activity.