HYDROCARBON RETAINING AND PURGING SYSTEM

• US 20100011746A1
• Filed: 09/25/2008
• Published: 01/21/2010
• Est. Priority Date: 07/17/2008
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Lupescu, Jason
• Granted Patent: US 8,413,433 B2
• Time in Patent Office: Days
• US Class Current: 60/278
• CPC Class Codes: F02M 25/12 the apparatus having means for generating such gases using rays and simultaneously generating ozone F02M27/06
• CPC Class Codes: F02M 26/35 with means for cleaning or treating the recirculated gases, e.g. catalysts, condensate traps, particle filters or heaters
• CPC Class Codes: F02M 26/36 with means for adding fluids other than exhaust gas to the recirculation passage; with reformers
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

Methods and systems are provided for reducing hydrocarbon emissions from an engine having a hydrocarbon retaining system. One example method comprises flowing exhaust gas over a hydrocarbon trap, the trap having a plurality of layers with different porosity and/or a different adsorptive affinity to hydrocarbon chains, and flowing hydrocarbons from a fuel tank over the hydrocarbon trap.

Claims

1. A method comprising:

flowing exhaust gas over a hydrocarbon trap, the trap having a plurality of layers of different porosity and/or of different adsorptive affinity to hydrocarbon chains; and

flowing hydrocarbons from a fuel tank over the hydrocarbon trap.

2. The method of claim 1 wherein the plurality of layers include zeolites.

3. The method of claim 1 further comprising, flowing a purging gas over the hydrocarbon trap to carry away adsorbed hydrocarbons, and routing the purging gas to an engine intake manifold.

4. The method of claim 1 further comprising, flowing hydrocarbons from a fuel tank over the hydrocarbon trap, flowing a purging gas over the hydrocarbon trap to carry away fuel tank adsorbed hydrocarbons and exhaust adsorbed hydrocarbons, routing the purging gas to an engine intake manifold, mixing the purging gas with engine intake air, and combusting the purging gas with engine intake air in a combustion chamber of the engine.

5. The method of claim 1 wherein the plurality of layers includes a first layer with a first pore size, and a second layer with a second, larger, pore size, the second layer interposed between the first layer and the exhaust gas.

6. A method of operating an engine having a hydrocarbon retaining system coupled to an engine exhaust, an engine intake, and a fuel tank, said hydrocarbon retaining system including a first zeolite layer with a first pore size, and a second zeolite layer with a second pore size, said first pore size being smaller than said second pore size, the method comprising:

during an engine cold start, routing exhaust gas to the hydrocarbon retaining system to store hydrocarbons in the hydrocarbon retaining system;

routing fuel vapors from the fuel tank to the hydrocarbon retaining system to store fuel tank hydrocarbons in the hydrocarbon retaining system; and

during a purging condition, purging the hydrocarbon retaining system with at least a purging gas, and directing the purging gas to the engine intake.

7. The method of claim 6 wherein the purging gas is exhaust gas.

8. The method of claim 6 wherein the purging gas is fresh air.

9. The method of claim 6 wherein the first zeolite layer further has a first adsorptive affinity to selected hydrocarbon chains and wherein the second zeolite layer further has a second adsorptive affinity to the selected hydrocarbon chains, said second affinity being greater than said first affinity.

10. The method of claim 9 wherein the selected hydrocarbon chains are long chains.

11. The method of claim 6 wherein the first and second zeolite layers are supported by a base substrate.

12. The method of claim 11 wherein the first zeolite layer is coated on the base substrate to form a lower layer and the second zeolite layer is coated on the first zeolite layer to form an upper layer, and wherein at least one of the first and second zeolite layers include metal-exchanged zeolites.

13. The method of claim 12 wherein the base substrate has a porosity of 30 to 95%.

14. A system for a vehicle including an engine intake, an engine exhaust, and a fuel tank, the system comprising:

a hydrocarbon retaining system coupled to the engine intake, the engine exhaust, and the fuel tank, said hydrocarbon retaining system including a first zeolite layer with a first pore size, and a second zeolite layer with a second pore size, said first pore size being smaller than said second pore size.

15. The system of claim 14 wherein the first zeolite layer further has a first adsorptive affinity to selected hydrocarbon chains and wherein the second zeolite layer further has a second adsorptive affinity to the selected hydrocarbon chains, said second affinity being greater than said first affinity, and wherein the first zeolite layer is coated on a substrate support to form a lower layer and the second zeolite layer is coated on the first zeolite layer to form an upper layer.

16. A system for a vehicle including an engine intake, an engine exhaust, and a fuel tank, the system comprising:

a hydrocarbon retaining system coupled to the engine intake, the engine exhaust, and the fuel tank, said hydrocarbon retaining system including a first zeolite layer with a first pore size and a first adsorptive affinity to selected hydrocarbon chains, and a second zeolite layer with a second pore size and a second adsorptive affinity to the selected hydrocarbon chains, the first pore size being smaller than the second pore size, said second affinity being greater than said first affinity.

17. The system of claim 16 wherein the first zeolite layer is coated on the substrate support to form an inner layer and the second zeolite layer is coated on the first zeolite layer to form an outer layer.

18. The system of claim 16 wherein the selected hydrocarbon chains are long chains.

19. The system of claim 17 wherein at least one of the first and second zeolite layers include metal-exchanged zeolites.

20. The system of claim 17 wherein the hydrocarbon retaining system further includes a third layer coated on the second layer.