초록 ▼

An engine system having a reductant delivery and storage system is described. In one example, a physical condition associated with a reductant storage device is correlated with a characteristic of a fluid stored in the reductant storage device to determine the availability and make-up of the stored

An engine system having a reductant delivery and storage system is described. In one example, a physical condition associated with a reductant storage device is correlated with a characteristic of a fluid stored in the reductant storage device to determine the availability and make-up of the stored fluid. In response, engine operation may be adjusted.

대표청구항 ▼

1. A method for operating an engine having a reductant system, comprising: identifying a reductant amount from reductant storage level and hydrostatic pressure of stored reductant;identifying a reductant make-up from reductant permittivity and reductant thermal conductivity;adjusting operation based

1. A method for operating an engine having a reductant system, comprising: identifying a reductant amount from reductant storage level and hydrostatic pressure of stored reductant;identifying a reductant make-up from reductant permittivity and reductant thermal conductivity;adjusting operation based on the identified reductant amount and make-up; andperforming a default diagnostic mode in response to disagreement between a NOx based reductant monitor and the identified reductant make-up from reductant permittivity and reductant thermal conductivity. 2. The method of claim 1, wherein said adjusting operation includes sending a signal prompting a reductant fill event based on the identified reductant amount and make-up. 3. The method of claim 1, wherein said adjusting operation includes using less or no reductant during engine operation based on the identified reductant amount and make-up. 4. The method of claim 1, wherein the make-up is a reductant concentration. 5. The method of claim 1 wherein the NOx based reductant monitor includes a NOx based reductant mass monitor. 6. The method of claim 1 wherein the NOx based reductant monitor includes a NOx based urea mass monitor. 7. A method for operating an engine having a reductant system, comprising: identifying a reductant storage amount from first and second sensors coupled to a reductant storage tank at different locations and each indicating different properties of stored reductant;identifying a reductant make-up from third and fourth sensors each indicating different properties of stored reductant;adjusting reductant delivery to downstream of an oxidation catalyst in an engine exhaust based on the identified reductant amount and make-up. 8. The method of claim 7, wherein the third sensor is a permittivity sensor, and the fourth sensor is a thermal conductivity sensor. 9. The method of claim 7, wherein the properties include one or more of an electrical conductivity, a viscosity, an opacity, and an acidity of the stored fluid. 10. The method of claim 7, wherein the adjusting operation includes degradation management, including temporarily stopping reductant usage. 11. The method of claim 7, wherein the adjusting reductant delivery further includes adjusting reductant injection into an exhaust of the engine upstream of an SCR catalyst based on the identified make-up and the amount. 12. The method of claim 7, wherein the first sensor is a level sensor and the second sensor is a hydrostatic pressure sensor coupled to a lower region of a reductant storage tank. 13. A method for operating an engine having a reductant system, comprising: identifying a reductant storage amount from a level sensor and a hydrostatic pressure sensor coupled to a reductant storage tank at different locations, the hydrostatic pressure sensor coupled to a lower region of the storage tank;identifying a reductant make-up from permittivity and thermal conductivity sensors each indicating different properties of stored reductant; andadjusting operation based on the identified reductant amount and make-up. 14. The method of claim 10, wherein the adjusting operation includes degradation management, including temporarily stopping reductant usage. 15. The method of claim 10, wherein the adjusting reductant delivery further includes adjusting reductant injection into an exhaust of the engine upstream of an SCR catalyst based on the identified make-up and the amount.