1. An exhaust aftertreatment system, comprising:
a NOx adsorber-catalyst configured to treat an exhaust flow;
an SCR catalyst configured to adsorb ammonia released by the NOx adsorber-catalyst during denitration and to subsequently use the ammonia to reduce NOx in the exhaust;
a particulate filter located upstream of the NOx adsorber-catalyst or downstream of the SCR catalyst; and
means for preventing the SCR catalyst from becoming heated to near the same peak temperatures as the NOx adsorber-catalyst during desulfation of the NOx adsorber-catalyst, the means being disposed between the NOx adsorber-catalyst and the SCR catalyst;
wherein the means comprises a flow diverter configured to prevent the exhaust leaving the NOx adsorber-catalyst from entering the SCR catalyst during desulfation of the NOx adsorber-catalyst.
2. A method of desulfating an NOx adsorber-catalyst in an exhaust aftertreatment system comprising an NOx adsorber-catalyst followed by an SCR catalyst, comprising:
in a first step, providing a flow of gas heated to at least about 650\xb0 C. to the NOx adsorber-catalyst, wherein the flow of gas passes through the NOx adsorber-catalyst and then the SCR catalyst;
maintaining the flow until a time after the NOx adsorber-catalyst has been heated by the gas to at least about 650\xb0 C., but terminating the flow before the SCR catalyst has reached a temperature of 550\xb0 C.;
in a second step, providing a second flow of gas at a temperature of about 500\xb0 C. or less to the NOx adsorber-catalyst, wherein the second flow of gas passes through the NOx adsorber-catalyst and then the SCR catalyst;
maintaining the second flow until a time after the NOx adsorber-catalyst has been cooled by the gas to a temperature at or below about 550\xb0 C.;
repeating the first and second steps at least several times to complete the desulfation.
3. The method of claim 2, wherein there is a device between the NOx adsorber-catalyst and the SCR catalyst, the device having a substantial thermal mass in comparison to the SCR catalyst.
4. The method of claim 3, wherein the thermal mass is a particulate filter.
5. The method of claim 3, wherein exhaust aftertreatment system comprises a particulate filter either upstream of the NOx adsorber-catalyst or downstream of the SCR catalyst.
6. A method of desulfating an NOx adsorber-catalyst in an exhaust aftertreatment system comprising an NOx adsorber-catalyst followed by an SCR catalyst, comprising:
cycling the temperature of the NOx adsorber-catalyst;
creating a reducing environment in the NOx adsorber-catalyst during portions of the cycles where the NOx adsorber-catalyst is at temperatures effective for desulfation;
wherein the cycles have peak temperatures in a range effective for desulfation and an average temperature that is at least 100\xb0 C. lower;
wherein peak temperature reached by the SCR catalyst during the cycles is at least 100\xb0 C. lower than the peak temperature reached by the NOx adsorber-catalyst.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A method for verifying an electronic financial transaction, the method comprising:
generating a user interface comprising a security code, the user interface associating different portions of the code with different parts of a user input device, and associating at least one code portion with a user input device part having visual indicia dissimilar to the visual representation of the code portion;
detecting activation of the user input device in a manner that generates a code; and
determining whether the code generated by activation of the user input device corresponds to the security code.
2. The method of claim 1, wherein the security code is a sequence of numerals.
3. The method of claim 1, wherein generating a user interface comprises inserting the portions of the security code in a random order in the user interface.
4. The method of claim 3, wherein the order of the portions of the security code changes each time the code is inserted.
5. The method of claim 1, wherein generating a user interface comprises inserting, in the user interface, symbols that are comparable to the code portions but that are not part of the security code so that the symbols are associated with different parts of the user input device by the user interface.
6. The method of claim 1, further comprising:
detecting a financial transaction card;
generating a user interface comprising a query for a second security code;
detecting activation of a user input device in a manner that generates a code; and
generating a message to have the generated code validated.
7. The method of claim 6, wherein the financial transaction card comprises a magnetic strip storing card owner identity data.
8. A system for verifying an electronic financial transaction, the system comprising:
a display device operable to display a user interface;
a user input device comprising parts operable to detect user activation in a manner that generates a code; and
a processor operable to:
generate a user interface comprising a security code, the user interface associating different portions of the code with different parts of the user input device, and associating at least one code portion with a user input device part having visual indicia dissimilar to the visual representation of the code portion, and
determine whether the code generated by activation of the user input device corresponds to the security code.
9. The system of claim 8, wherein the processor is further operable to insert the portions of the security code in a random order in the user interface.
10. The system of claim 9, wherein the order of the portions of the security code changes each time the code is inserted.
11. The system of claim 9, wherein the processor is further operable to randomize the order of the security code portions in the user interface.
12. The system of claim 8, wherein the processor, in generating amuser interface, is further operable to insert symbols that are comparable to the code portions but that are not part of the security code in the user interface so that the symbols are associated with different parts of the user input device by the user interface.
13. The system of claim 8, wherein the user input device comprises Automated Teller Machine function selection keys.
14. The system of claim 8, further comprising a card reader for detecting and reading a financial transaction card, wherein the processor is further operable to generate a user interface comprising a query for a second security code and generate a message to have a generated code validated.
15. An article comprising a machine-readable medium storing instructions operable to cause one or more machines to perform operations comprising:
generating a user interface comprising a security code, the user interface associating different portions of the code with different parts of a user input device, and associating at least one code portion with a user input device part having visual indicia dissimilar to the visual representation of the code portion;
detecting activation of the user input device in a manner that generates a code; and
determining whether the code generated by activation of the user input device corresponds to the security code.
16. The article of claim 15, wherein generating a user interface comprises inserting the portions of the security code are in a random order in the user interface.
17. The article of claim 16, wherein the order of the portion of the security code changes each time the code is inserted.
18. The article of claim 15, wherein generating a user interface comprises inserting symbols that are comparable to the code portions but that are not part of the security code in the user interface so that the symbols that are associated with different parts of the user input device by the user interface.
19. The article of claim 15, wherein the instructions are further operable to cause one or more machines to perform operations comprising:
detecting a financial transaction card;
generating a user interface comprising a query for a second security code;
detecting activation of a user input device in a manner that generated a code; and
generating a message to have the detected code validated.
20. A method for verifying an electronic financial transaction, the method comprising:
receiving a message comprising identity data for an electronic financial transaction;
retrieving a security code associated with the identity data, the security code for presentation in a user interface that associates different portions of the code with different parts of a user input device, with at least one code portion being associated with a user input device part having visual indicia dissimilar to the visual representation of the code portion; and
generating a message including the security code.
21. The method of claim 20, further comprising:
randomizing the order of the portions of the security code; and
inserting the randomized order into the message along with the security code.
22. The method of claim 21, further comprising inserting symbols that are comparable to the code portions but that are not part of the security code into the randomized order.
23. The method of claim 20, further comprising determining whether the security code is required.
24. A system for verifying an electronic financial transaction, the system comprising:
a memory operable to store identity data for card owners and associated security codes;
a communication interface operable to receive a message comprising identity data for an electronic financial transaction; and
a processor operable to:
retrieve a security code associated with the identity data, the security code for presentation in a user interface that associates different portions of the code with different parts of a user input device, with at least one code portion being associated with a user input device part having visual indicia dissimilar to the visual representation of the code portion, and
generate a message including the security code.
25. The system of claim 24, wherein the processor is further operable to:
randomize the order of the portions of the security code; and
insert the randomized order into the message along with the security code.
26. The system of claim 25, wherein the processor is further operable to insert symbols that are comparable to the code portions but that are not part of the security code into the randomized order.
27. The system of claim 24, wherein the processor is further operable to determine whether the security code is required.
28. An article comprising a machine-readable medium storing instructions operable to cause one or more machines to perform operations comprising:
detecting a message comprising identity data for an electronic financial transaction;
retrieving a security code associated with the identity data, the security code for presentation in a user interface that associates different portions of the code with different parts of a user input device, with at least one code portion being associated with a user input device part having visual indicia dissimilar to the visual representation of the code portion; and
generating a message including the security code.
29. The article of claim 28, wherein the instructions are further operable to cause one or more machines to perform operations comprising:
randomizing the order of the portions of the security code; and
inserting the randomized order into the message along with the security code.
30. The article of claim 29, wherein the instructions are further operable to cause one or more machines to perform operations comprising inserting symbols that are comparable to the code portions but that are not part of the security code into the randomized order.
31. The article of claim 28, wherein the instructions are further operable to cause one or more machines to perform operations comprising determining whether the security code is required.
32. A system for verifying an electronic financial transaction, the system comprising:
a remote financial transaction station operable to:
detect a financial transaction card comprising a magnetic strip storing card owner identity data,
read the data from the card,
generate a user interface comprising a query for a first security code,
detect activation of a user input device in a manner that generates a code,
generate a message comprising card owner identity data and the generated code,
receive a response message,
determine whether the generated code was validated,
if the generated code was validated, determine whether a second security code was received in the response message,
if a second security code was received, generate a user interface comprising:
the second security code, the user interface associating different portions of the code with different parts of a user input device, and associating at least one code portion with a user input device part having visual indicia dissimilar to the visual representation of the code portion, the portions of the code in a random order in the user interface, and
symbols that are comparable to the code portions but that are not part of the security code so that the symbols are associated with different parts of the user input device,
detect activation of the user input device in a manner that generates a second code,
and
determine whether the second generated code corresponds to the second security code; and
a financial transaction manager operable to:
receive the message comprising card owner identity data and the generated code,
determine whether the generated code is valid by examining a card file,
if the generated code is valid, determine whether the second security code is required,
if the second security code is required, retrieve the second security code, the second security code associated with the identity data,
randomize the order of the portions of the second security code,
insert into the randomized order symbols that are comparable to the code portions but that are not part of the security code, and
generate a message including the second security code and the randomized, symbol-inserted version of the second security code.