Diesel aftertreatment systems

• US 20040098975A1
• Filed: 11/21/2002
• Published: 05/27/2004
• Est. Priority Date: 11/21/2002
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Ruona, William Charles, van Nieuwstadt, Michiel J., Upadhyay, Devesh, Goebelbecker, Michael
• Granted Patent: US 6,834,498 B2
• Time in Patent Office: Days
• US Class Current: 60/286
• CPC Class Codes: B01D 53/9431 Processes characterised by a specific device
• CPC Class Codes: B01D 53/9495 Controlling the catalytic process
• CPC Class Codes: F01N 13/009 having two or more separate purifying devices arranged in series
• CPC Class Codes: F01N 2240/16 an electric heater, i.e. a resistance heater
• CPC Class Codes: F01N 2570/10 Carbon or carbon oxides
• CPC Class Codes: F01N 2570/12 Hydrocarbons
• CPC Class Codes: F01N 2570/14 Nitrogen oxides
• CPC Class Codes: F01N 2610/03 the substance being hydrocarbons, e.g. engine fuel
• CPC Class Codes: F01N 2610/08 with prior mixing of the substances with a gas, e.g. air
• CPC Class Codes: F01N 2610/10 the substance being heated, e.g. by heating tank or supply line of the added substance
• CPC Class Codes: F01N 2610/107 using glow plug heating elements
• CPC Class Codes: F01N 3/023 using means for regenerating the filters, e.g. by burning trapped particles by electrically controlling the supply of combustible mixture or its constituents only F02D41/0235
• CPC Class Codes: F01N 3/035 with catalytic reactors , e.g. catalysed diesel particulate filters
• CPC Class Codes: F01N 3/2066 Selective catalytic reduction [SCR]
• CPC Class Codes: F02D 41/1475 Regulating the air fuel ratio at a value other than stoichiometry
• 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

A method and a system for improved reductant delivery to an exhaust gas aftertreatment device for a lean burn internal combustion engine exhaust is presented. The system includes a heated evaporator unit into which a mixture of reductant and air in injected, wherein the mixture is vaporized and introduced into the exhaust gas aftertreatment device. Introducing the reductant mixed with air into the heated evaporator unit prevents lacquering and soot deposits on the heated element housed inside the unit, and also speeds up the vaporization process due to better reductant distribution thus reducing system response delays and improving conversion efficiency of the exhaust gas aftertreatment device. The reductant delivery system is further improved by adding a catalyst to it, and by preventing the reductant and air mixture from coming into direct contact with the surface of the heating element.

Claims

1. A reductant delivery system, comprising:

an evaporator unit including at least a heating element;

a mixing device having at least one inlet and at least one outlet coupled to said evaporator unit; and

a controller for introducing reductant and air into said mixing device through said inlet, injecting a mixture of said reductant and said air through said outlet into said evaporator unit thereby causing evaporation of said reductant and air mixture.

2. The system as set forth in claim 1 wherein said reductant is hydrocarbon.

3. The system as set forth in claim 1 further comprising a delivery tube for housing said injected reductant and air mixture, wherein said reductant and air mixture evaporates inside said delivery tube without coming into direct contact with a surface of said heating element.

4. The system as set forth in claim 1 wherein said heating element is an electrically heated elongated heater plug.

5. The system as set forth in claim 4 wherein said heater plug is cylindrically shaped.

6. The system as set forth in claim 4 wherein said heater plug is rectangular shaped.

7. The system as set forth in claim 1 wherein said evaporator unit further comprises an oxidation catalyst.

8. The system as set forth in claim 1 wherein said mixing device outlet is configured to inject said mixture of said reductant and said air onto at least two predetermined areas on a surface of said heating element.

9. The system as set forth in claim 8 wherein said controller is further adapted to enable and disable injection of said mixture of said reductant and said air onto said predetermined areas of said heating device.

10. A method for vaporizing a substance in a reductant delivery system for an exhaust gas aftertreatment device, the system having at least a heating element, the method comprising:

generating a mixture by mixing a predetermined amount of reductant with a predetermined amount of air; and

injecting said mixture into the reductant delivery system thereby causing said mixture to vaporize.

11. The method as set forth in claim 10 wherein said reductant is hydrocarbon.

12. The method as set forth in claim 10 wherein the exhaust gas aftertreatment device is an Active Lean NOx Catalyst (ALNC).

13. The method as set forth in claim 12 further comprising directing said vaporized mixture into said ALNC.

14. A method for controlling a reductant delivery system having at least a heating element, the system coupled upstream of an exhaust gas aftertreatment device of an internal combustion engine in a mobile vehicle, the method comprising:

injecting air into the system;

injecting a reductant into the system thereby creating a vaporized mixture; and

directing said vaporized mixture into the exhaust gas aftertreatment device.

15. The method as set forth in claim 14 wherein said reductant is hydrocarbon.

16. The method as said forth in claim 14 wherein the engine is a diesel engine.

17. The method as set forth in claim 14 wherein the exhaust gas aftertreatment device is an ALNC.