Gasoline engine emissions treatment systems having particulate filters

• US 8,815,189 B2
• Filed: 04/15/2011
• Issued: 08/26/2014
• Est. Priority Date: 04/19/2010
• Status: Active Grant

• Current Assignee: BASF Corporation (BASF SE)
• Original Assignee: BASF Corporation (BASF SE)
• Inventors: Arnold, Mirko, Siani, Attilio, Wassermann, Knut, Siemund, Stephan
• Primary Examiner(s): VANOY, TIMOTHY C
• Application Number:
  US13/087,497
• Publication Number:
  US 20110252773A1
• Time in Patent Office: 1,229 Days
• Field of Search: 423/213.2, 423/213.7, 602/74, 602/99, 603/01, 952/85, 555/24, 55D/IG.30
• US Class Current: 423/213.2
• CPC Class Codes: B01D 2255/1021 Platinum
• CPC Class Codes: B01D 2255/1023 Palladium
• CPC Class Codes: B01D 2255/1025 Rhodium
• CPC Class Codes: B01D 2255/407 Zr-Ce mixed oxides
• CPC Class Codes: B01D 2255/9037 More than three zones
• CPC Class Codes: B01D 2255/908 O2-storage component incorporated in the catalyst
• CPC Class Codes: B01D 2255/9202 Linear dimensions
• CPC Class Codes: B01D 2255/9205 Porosity
• CPC Class Codes: B01D 2279/30 for treatment of exhaust gases from IC Engines
• CPC Class Codes: B01D 46/2429 of the honeycomb walls or cells
• CPC Class Codes: B01D 46/24491 Porosity
• CPC Class Codes: B01D 46/24492 Pore diameter
• CPC Class Codes: B01D 53/945 characterised by a specific catalyst
• CPC Class Codes: B01J 23/58 with alkali- or alkaline earth metals
• CPC Class Codes: B01J 23/63 with rare earths or actinides
• CPC Class Codes: B01J 35/19 Catalysts containing parts with different compositions
• CPC Class Codes: B01J 35/40 characterised by dimensions, e.g. grain size in a colloidal state B01J35/23; crystallite size B01J35/77
• CPC Class Codes: B01J 35/657 larger than 1000 nm
• CPC Class Codes: B01J 37/0215 Coating
• CPC Class Codes: F01N 13/009 having two or more separate purifying devices arranged in series
• CPC Class Codes: F01N 13/0097 : the purifying devices are arranged in a single housing
• CPC Class Codes: F01N 2510/06 : for exhaust purification, e.g. catalytic reaction
• CPC Class Codes: F01N 3/035 : with catalytic reactors , e.g. catalysed diesel particulate filters
• CPC Class Codes: F01N 3/0821 : combined with particulate filters catalysed diesel particulate filters F01N3/035
• CPC Class Codes: F01N 3/101 : Three-way catalysts
• CPC Class Codes: F01N 3/2066 : Selective catalytic reduction [SCR]
• CPC Class Codes: Y02A 50/20 : Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02T 10/12 : Improving ICE efficiencies

Abstract

Exhaust systems and components are suitable for use with gasoline engines to capture particulates and to reduce gaseous emissions, where three-way conversion (TWC) catalysts located on a particulate filters are provided. Coated particle filters having washcoat loadings in the range of 1 to 4 g/ft³ result in minimal impact on back pressure while simultaneously providing TWC catalytic activity and particle trapping functionality to meet increasingly stringent regulations such as Euro 6. Sufficient to high levels of oxygen storage components (OSC) are also delivered on and/or within the filter. The filters can have a coated porosity that is substantially the same as its uncoated porosity. The TWC catalytic material can comprise a particle size distribution such that a first set of particles has a first d₉₀ particle size of 7.5 μm or less and a second set of particles has a second d₉₀ particle size of more than 7.5 μm.

Claims

1. An emission treatment system downstream of a gasoline direct injection engine for treatment of an exhaust stream comprising hydrocarbons, carbon monoxide, nitrogen oxides, and particulates, the emission treatment system comprising a catalyzed particulate filter comprising:

a three-way conversion (TWC) catalytic material that is coated onto or within a particulate filter having an uncoated porosity;

wherein the catalyzed particulate filter has a coated porosity that is substantially the same as the uncoated porosity of the particulate filter.

2. The emission treatment system of claim 1, wherein the TWC catalytic material stores at least 100 mg/L of oxygen after a full useful life aging.

3. The emission treatment system of claim 1, wherein the uncoated porosity and the coated porosity are within 7% of each other.

4. The emission treatment system of claim 1, wherein the uncoated porosity and the coated porosity are in the range of 55 to 70%.

5. The emission treatment system of claim 1 comprising the TWC catalytic material in an amount in the range of 1.0 to 4.0 g/in³ (61 to 244 g/L).

6. The emission treatment system of claim 1, wherein the particulate filter comprises a pore size distribution such that a first set of pores has a first mean pore size of 30 μ

m or less and second set of pores has a second mean pore size of more than 30 μ

m.

7. The emission treatment system of claim 6, wherein the first mean pore size is in the range of 5-30 μ

m and the second mean pore size is in the range of 30-300 μ

m.

8. The emission treatment system of claim 1, wherein the TWC catalytic material comprises a particle size distribution such that a first set of particles has a first d₉₀ particle size of 7.5 μ

m or less and a second set of particles has a second d₉₀ particle size of more than 7.5 μ

m.

9. The emission treatment system of claim 8, wherein the first d₉₀ particle size is 6.0 μ

m or less and the second d₉₀ particle size is 10.0 μ

m or more.

10. The emission treatment system of claim 8, wherein the first d₉₀ particle size is in the range of 1-7.5 μ

m and the second d₉₀ particle size is in the range of 7.6-100 μ

m.

11. The emission treatment system of claim 8, wherein the TWC catalytic material comprises the second set of particles in an amount in the range of 10-50% by weight.

12. The emission treatment system of claim 1, wherein the TWC catalytic material is formed from a single washcoat composition that is coated onto or within an inlet side, an outlet side, or both of the particulate filter.

13. The emission treatment system of claim 1, wherein the TWC catalytic material comprises rhodium, palladium, ceria or a ceria composite, and alumina.

14. The emissions treatment system of claim 12, wherein a first single washcoat layer is present on the inlet side along 100% of the axial length of the particulate filter and a second single washcoat layer is present on the outlet side along 100% of the axial length of the particulate filter.

15. The emissions treatment system of claim 12, wherein a first single washcoat layer is present on the inlet side along 50 to 75% of the axial length of the particulate filter from the upstream end and a second single washcoat layer is present on the outlet side along 50 to 75% of the axial length of the particulate filter from the downstream end.

16. The emissions treatment system of claim 12, wherein a first single washcoat layer is present on the inlet side along up to 50% of the axial length of the particulate filter from the upstream end and a second single washcoat layer is present on the outlet side along up to 50% of the axial length of the particulate filter from the downstream end.

17. The emission treatment system of claim 1, wherein the particulate filter comprises cordierite, alumina, silicon carbide, aluminum titanate, or mullite.

18. A catalyzed particulate filter located in an emission treatment system downstream of a gasoline direct injection engine for treatment of an exhaust stream comprising hydrocarbons, carbon monoxide, nitrogen oxides, and particulates, the catalyzed particulate filter comprising:

a three-way conversion (TWC) catalytic material that is coated onto or within a particulate filter in an amount in the range of 1.0 to 4 g/in³ (122 to 244 g/L);

wherein the TWC catalytic material stores at least 100 mg/L of oxygen after a full useful life aging and comprises an oxygen storage component in an amount in the range of 1.0 to 4.0 g/in³ (122 g/L to 244 g/L);

wherein the particulate filter comprises a pore size distribution such that a first set of pores has a first mean pore size of 30 μ

m or less and second set of pores has a second mean pore size of more than 30 μ

m; and

wherein the TWC catalytic material comprises a particle size distribution such that a first set of particles has a first d₉₀ particle size of 7.5 μ

m or less and a second set of particles has a second d₉₀ particle size of more than 7.5 μ

m.

19. The emissions treatment system of claim 18, wherein an upstream zone and a downstream zone both comprise a palladium component, wherein the upstream zone comprises the palladium component in an amount that is greater than the amount of the palladium component in the downstream zone.

20. The emissions treatment system of claim 18, wherein a first single washcoat layer is present on the inlet side along 50 to 75% of the axial length of the particulate filter from the upstream end and a second single washcoat layer is present on the outlet side along 50 to 75% of the axial length of the particulate filter from the downstream end.

23. The method of claim 21, comprising providing the catalyzed particulate filter of claim 18.

21. A method of treating an exhaust gas comprising hydrocarbons, carbon monoxide, nitrogen oxides, and particulates, the method comprising:

providing a catalyzed particulate filter comprising a three-way conversion (TWC) catalytic material coated onto or within a particulate filter in an amount of effective to provide a particulate emissions number of no more than 6×

10¹¹ per kilometer;

locating the catalyzed particulate filter downstream of a gasoline direct injection engine; and

contacting exhaust gas from the gasoline direct injection engine with the catalyzed particulate filter.

22. The method of claim 21 further comprising providing full TWC functionality by the catalyzed particulate filter, a TWC catalyst on a flow through substrate, or combinations thereof.

24. The method of claim 21 further comprising providing the TWC catalytic material in an amount in the range of 1.0-4.0 g/in³ (61-244 g/L).

25. The method of claim 21 further comprising storing at least 100 mg/L of oxygen by the TWC catalytic material after a full useful life aging.

26. A method of making a catalyzed particulate filter, the method comprising:

providing a particulate filter;

providing a three-way conversion (TWC) catalytic material; and

coating the TWC catalytic material onto or into the particulate filter in an amount of at least 1.0 g/in³ (61 g/L) to form the catalyzed particulate filter such that the catalyzed particulate filter has a coated porosity that is substantially the same as an uncoated porosity of the particulate filter.