System and method for NOx reduction optimization

Abstract

An engine controller determines the cost of operating a combustion engine and the cost of operating an emissions after-treatment device. Accordingly, the engine controller adjusts parameters for operation of the engine and the after-treatment device to ensure cost-effective use of the engine and the after-treatment device while complying with exhaust emissions requirements. In particular, the engine controller receives the price of fuel consumed by the engine and the price of reductant used by the after-treatment device to determine the respective cost of operation. Specifically, the fuel is diesel fuel used in a diesel engine; the reductant is urea use in a urea-based Selective Catalytic Reduction (SCR) system; and the regulated exhaust emissions is nitrogen oxide (NOx) emissions. The engine operating parameters may include cooled exhaust gas recirculation airflow, fuel injection timing, fuel injection pressure, and air-to-fuel ratio. The SCR system operating parameters may include the volume of urea injected.

Description

BRIEF SUMMARY OF THE DRAWINGS

FIG. 1 provides a chart illustrating how the overall system NOx is created according to various characteristics of the engine and a urea-based SCR system.

FIG. 2 provides a chart illustrating an exemplary embodiment with the data that are input into an ECM and how output signals are directed.

FIG. 3 provides a chart illustrating exemplary output signals from the ECM to maximize fuel efficiency when the cost of operating the engine is higher than the cost of operating the SCR system.

FIG. 4 provides a chart illustrating exemplary output signals from the ECM to minimize urea usage when the cost of operating the engine is lower than the cost of operating the SCR system.

FIG. 5 provides a chart illustrating another embodiment of the present invention which utilizes additional input regarding the urea supply.

FIG. 6 provides a chart illustrating exemplary output signals from the ECM to minimize urea usage when the supply of urea usage drops below a critical threshold level.

Claims

1. A system for controlling exhaust emissions from a combustion engine, the system comprising: a combustion engine adapted to produce a first mixture of exhaust emissions after combustion of fuel according to one or more engine operating parameters;an exhaust after-treatment device adapted to convert the first exhaust emissions to a second mixture of exhaust emissions according to one or more after-treatment parameters; andan engine controller adapted to control the engine and the after-treatment device,wherein the engine controller determines a cost to operate the engine and a cost to operate the after-treatment device, compares the cost to operate the engine with the cost to operate the after-treatment device, and at least one of adjusts the one or more engine operating parameters and adjusts the one or more after-treatment parameters, at least partially based on the comparison of the cost to operate the engine with the cost to operate the after-treatment device.

2. The system for controlling exhaust emissions from a combustion engine according to claim 1, wherein the engine controller at least one of adjusts the one or more engine operating parameters and adjusts the one or more after-treatment parameters, based partially further on a limit for an amount of a part in the second mixture of exhaust emissions.

3. The system for controlling exhaust emissions from a combustion engine according to claim 2, wherein the part in the second mixture of exhaust emissions comprises nitrogen oxides.

4. The system for controlling exhaust emissions from a combustion engine according to claim 1, wherein the engine is a diesel engine and the fuel is diesel fuel.

5. The system for controlling exhaust emissions from a combustion engine according to claim 1, wherein the engine controller receives a fuel price to determine the cost to operate the engine.

6. The system for controlling exhaust emissions from a combustion engine according to claim 5, wherein the fuel price is entered into the engine controller through a manual input device.

7. The system for controlling exhaust emissions from a combustion engine according to claim 5, wherein the fuel price is entered into the engine controller through an automated network.

8. The system controlling exhaust emissions from a combustion engine according to claim 1, wherein the after-treatment device is a selective catalytic reduction device.

9. The system for controlling exhaust emissions from a combustion engine according to claim 8, wherein the selective catalytic reduction device injects a reductant into the first exhaust emissions.

10. The system for controlling exhaust emissions from a combustion engine according to claim 9, wherein the reductant is urea.

11. The system for controlling exhaust emissions from a combustion engine according to claim 9, wherein the engine controller receives a reductant price to determine the cost to operate the after-treatment device.

12. The system for controlling exhaust emissions from a combustion engine according to claim 11, wherein the reductant price is entered into the engine controller through a manual input device.

13. The system for controlling exhaust emissions from a combustion engine according to claim 11, wherein the reductant price is entered into the engine controller through an automated network.

14. The system for controlling exhaust emissions from a combustion engine according to claim 11, wherein the engine controller receives a fuel price to determine the cost to operate the engine,wherein the one or more engine operating parameters comprises at least one of a fuel injector timing, an air-to-fuel ratio, an injection pressure, and a cooled exhaust gas recirculation airflow, andwherein the one or more after-treatment parameters comprises a reductant injection volume.

15. The system for controlling exhaust emissions from a combustion engine according to claim 14, wherein if the cost of operating the engine is greater than the cost to operate the after-treatment device, the engine controller at least one of adjusts the one or more engine operating parameters and adjusts the one or more after-treatment parameters by at least one of advancing the fuel injector timing, increasing the air-to-fuel ratio, increasing the fuel injection pressure, decreasing the cooled exhaust gas recirculation airflow, and increasing the reductant injection volume.

16. The system for controlling exhaust emissions from a combustion engine according to claim 14, wherein if the cost of operating the engine is less than the cost to operate the after-treatment device, the engine controller at least one of adjusts the one or more engine operating parameters and adjusts the one or more after-treatment parameters by at least one of retarding the fuel injector timing, decreasing the air-to-fuel ratio, decreasing the fuel injection pressure, increasing the cooled exhaust gas recirculation airflow, and decreasing from the reductant injection volume.

17. The system for controlling exhaust emissions from a combustion engine according to claim 1, wherein the engine controller receives sensor data from the engine and the after-treatment device.

18. The system for controlling exhaust emissions from a combustion engine according to claim 9, wherein the engine controller further determines an optimal rate of reductant usage, and wherein the engine controller adjusts the one or more after-treatment parameters by at least adjusting reductant usage to a rate not greater than the optimal rate of reductant usage.

19. The system for controlling exhaust emissions from a combustion engine according to claim 18, wherein the engine controller receives input data indicating a volume of available urea and a number of route miles to be driven by the system.

20. A system for controlling exhaust emissions from a combustion engine, the system comprising: a combustion engine adapted to produce a first mixture of exhaust emissions after combustion of fuel according one or more engine operating parameters;an exhaust after-treatment device adapted to convert the first exhaust emissions to a second mixture of exhaust emissions according to one or more after-treatment parameters, and adapted to inject a reductant from a supply of the reductant into the first exhaust emissions; andan engine controller adapted to control the engine and the after-treatment device, and adapted to determine the supply of the reductant,wherein, according to the supply of the reductant, the engine controller at least one of adjusts the one or more engine operating parameters and adjusts the one or more after-treatment parameters.

21. The system for controlling exhaust emissions from a combustion engine according to claim 20, wherein the one or more engine operating parameters comprise at least one of a fuel injector timing, an air-to-fuel ratio, a fuel injection pressure, and a cooled exhaust gas recirculation airflow, andwherein the one or more after-treatment parameters comprise a reductant injection volume.

22. The system for controlling exhaust emissions from a combustion engine according to claim 21, wherein if the supply of the reductant falls below a threshold, the engine controller at least one of adjusts the one or more engine operating parameters and adjusts the one or more after-treatment parameters by at least one of retarding the fuel injector timing, decreasing the air-to-fuel ratio, decreasing the fuel injection pressure, increasing the cooled exhaust gas recirculation airflow, and decreasing the reductant injection volume.

23. The system for controlling exhaust emissions from a combustion engine according to claim 20, wherein the reductant is urea.

24. A method for controlling exhaust emissions from a combustion engine, the method comprising: determining a cost to operate a combustion engine and a cost to operate an after-treatment device;comparing the cost to operate the combustion engine with the cost to operate the after-treatment device; andat least one of adjusting one or more engine operating parameters and adjusting one or more after-treatment parameters, at least partially based on the comparison of the cost to operate the engine with the cost to operate the after-treatment device,wherein the one or more engine operating parameters determine a first mixture of exhaust emissions after combustion of fuel by the combustion engine, andwherein the one or more after-treatment parameters determine a second mixture of exhaust emissions converted from the first exhaust emissions by the exhaust after-treatment device.

25. The method for controlling exhaust emissions from a combustion engine according to claim 24, wherein the step of at least one of adjusting the one or more engine operating parameters and adjusting the one or more after-treatment parameters is based partially further on a limit for an amount of a part in the second mixture of exhaust emissions.

26. The method for controlling exhaust emissions from a combustion engine according to claim 25, wherein the part in the second mixture of exhaust emissions comprises nitrogen oxides.

27. The method for controlling exhaust emissions from a combustion engine according to claim 24, wherein the combustion engine is a diesel engine and the fuel is diesel fuel.

28. The method for controlling exhaust emissions from a combustion engine according to claim 24, wherein the step of determining the cost to operate the engine includes receiving a fuel price.

29. The method for controlling exhaust emissions from a combustion engine according to claim 24, wherein the step of determining the cost to operate the engine includes receiving a fuel price through a manual input device.

30. The method for controlling exhaust emissions from a combustion engine according to claim 24, wherein the step of determining the cost to operate the engine includes receiving a fuel price through an automated network.

31. The method controlling exhaust emissions from a combustion engine according to claim 24, wherein the after-treatment device is a selective catalytic reduction device.

32. The method for controlling exhaust emissions from a combustion engine according to claim 31, wherein the after-treatment device injects a reductant into the first exhaust emissions.

33. The method for controlling exhaust emissions from a combustion engine according to claim 31, wherein the reductant is urea.

34. The method for controlling exhaust emissions from a combustion engine according to claim 32, wherein the step of determining the cost to operate the after-treatment device includes receiving a reductant price.

35. The method for controlling exhaust emissions from a combustion engine according to claim 32, wherein the step of determining the cost to operate the after-treatment device includes receiving a reductant price through a manual input device.

36. The method for controlling exhaust emissions from a combustion engine according to claim 32, wherein the step of determining the cost to operate the after-treatment device includes receiving a reductant price through an automated network.

37. The method for controlling exhaust emissions from a combustion engine according to claim 34, wherein the step of determining the cost to operate the engine includes receiving a fuel price,wherein the one or more engine operating parameters comprises at least one of a fuel injector timing, an air-to-fuel ratio, an injection pressure, and a cooled exhaust gas recirculation airflow, andwherein the one or more after-treatment parameters comprises a reductant injection volume.

38. The method for controlling exhaust emissions from a combustion engine according to claim 37, wherein if the cost of operating the engine is greater than the cost to operate the after-treatment device, the step of at least one of adjusting the one or more engine operating parameters and adjusting the one or more after-treatment parameters includes at least one of advancing the fuel injector timing, increasing the air-to-fuel ratio, increasing the fuel injection pressure, decreasing the cooled exhaust gas recirculation airflow, and increasing the reductant injection volume.

39. The method for controlling exhaust emissions from a combustion engine according to claim 37, wherein if the cost of operating the engine is less than the cost to operate the after-treatment device, the step of at least one of adjusting the one or more engine operating parameters and adjusting the one or more after-treatment parameters includes at least one of retarding the fuel injector timing, decreasing the air-to-fuel ratio, decreasing the fuel injection pressure, increasing the cooled exhaust gas recirculation airflow, and decreasing from the reductant injection volume.

40. The method for controlling exhaust emissions from a combustion engine according to claim 24, wherein the step of determining a cost to operate a combustion engine and a cost to operate an after-treatment device includes receiving sensor data from the engine and the after-treatment device.

41. The method for controlling exhaust emissions from a combustion engine according to claim 32, further comprising determining an optimal rate of reductant usage, and wherein the step of adjusting the one or more after-treatment parameters includes at least adjusting reductant usage to a rate not greater than the optimal rate of reductant usage.

42. The method for controlling exhaust emissions from a combustion engine according to claim 41, further comprising before the step of determining an optimal rate of reductant usage, receiving input data indicating a volume of available urea and a number of route miles to be driven using the engine.

43. A method for controlling exhaust emissions from a combustion engine, the method comprising: determining a supply of a reductant for an exhaust after-treatment device; andat least one of adjusting one or more engine operating parameters and adjusting one or more after-treatment parameters according to the supply of a reductant,wherein the one or more engine operating parameters determine a first mixture of exhaust emissions after combustion of fuel by a combustion engine,wherein the one or more after-treatment parameters determine a second mixture of exhaust emissions converted from the first exhaust emissions by the exhaust after-treatment device, andwherein the exhaust after-treatment device injects the reductant from a supply of the reductant into the first exhaust emissions.

44. The method for controlling exhaust emissions from a combustion engine according to claim 43, wherein the one or more engine operating parameters comprise at least one of a fuel injector timing, an air-to-fuel ratio, a fuel injection pressure, and a cooled exhaust gas recirculation airflow, andwherein the one or more after-treatment parameters comprise a reductant injection volume.

45. The method for controlling exhaust emissions from a combustion engine according to claim 44, wherein if the supply of the reductant falls below a threshold, the step of at least one of adjusting the one or more engine operating parameters and adjusting the one or more after-treatment parameters includes at least one of retarding the fuel injector timing, decreasing the air-to-fuel ratio, decreasing the fuel injection pressure, increasing the cooled exhaust gas recirculation airflow, and decreasing the reductant injection volume.

46. The method for controlling exhaust emissions from a combustion engine according to claim 43, wherein the reductant is urea.