SYSTEM FOR CONTROLLING ENGINE FUELING TO LIMIT ENGINE OUTPUT POWER

• US 20080271452A1
• Filed: 05/01/2007
• Published: 11/06/2008
• Est. Priority Date: 05/01/2007
• Status: Active Grant

• Current Assignee: Cummins Incorporated
• Original Assignee: Cummins Incorporated
• Inventors: Reynolds, David J., Schwab, Zachary, Gutman, Ralph
• Granted Patent: US 7,721,539 B2
• Time in Patent Office: Days
• US Class Current: 60/611
• CPC Class Codes: F02D 2200/0414 Air temperature
• CPC Class Codes: F02D 2250/26 by applying a torque limit
• CPC Class Codes: F02D 41/0007 for control of turbo-charged or super-charged engines control of the pumps per se F02B37/12
• CPC Class Codes: F02D 41/1447 with determination means using an estimation
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A method for controlling fueling of an internal combustion engine is provided. The engine may include an intake manifold, one or more exhaust manifolds and a turbocharger coupled between the intake and exhaust manifolds. The method may comprise estimating an operating condition of the turbocharger, determining a maximum value of an operating parameter as a function of the estimated operating condition of the turbocharger, measuring a value of the operating parameter, determining an error value as a function of the maximum value of the first operating parameter and the measured value of the operating parameter, and limiting fuel supplied to the engine based on the error value.

Claims

1. A method for controlling fueling of an internal combustion engine, the engine including an intake manifold, one or more exhaust manifolds and a turbocharger coupled between the intake and exhaust manifolds, the method comprising:

estimating an operating condition of the turbocharger,

determining a maximum value of an operating parameter as a function of the estimated operating condition of the turbocharger,

measuring a value of the operating parameter,

determining an error value as a function of the maximum value of the first operating parameter and the measured value of the operating parameter, and

limiting fuel supplied to the engine based on the error value.

2. The method of claim 1 wherein estimating an operating condition of the turbocharger comprises:

determining ambient pressure, and

estimating an inlet density of a compressor of the turbocharger as a function of the ambient pressure.

3. The method of claim 2 wherein estimating an operating condition of the turbocharger further comprises:

determining ambient temperature, and

estimating the inlet density of the compressor as a function of both the measured ambient pressure and the measured ambient temperature.

4. The method of claim 2 wherein determining a maximum value of an operating parameter comprises determining a maximum value of rotational speed of the turbocharger as a function of the inlet density of the compressor of the turbocharger,

and wherein measuring a value of the operating parameter comprises measuring turbocharger rotational speed.

5. The method of claim 4 wherein limiting fuel supplied to the engine comprises:

determining an engine acceleration value,

determining a limit value as a function of the error value and of the engine acceleration value in a manner that limits the turbocharger rotational speed to the maximum value of rotational speed of the turbocharger, and

limiting fuel supplied to the engine as a function of the limit value.

6. The method of claim 2 wherein determining a maximum value of an operating parameter comprises:

measuring turbocharger rotational speed, and

determining a maximum value of engine boost pressure as a function of the inlet density of the compressor of the turbocharger and also as a function of the measured turbocharger rotational speed.

7. The method of claim 6 wherein measuring a value of the operating parameter comprises measuring engine boost pressure.

8. The method of claim 7 wherein limiting fuel supplied to the engine comprises:

determining an engine acceleration value,

determining a limit value as a function of the error value and of the engine acceleration value in a manner that limits the engine boost pressure to the maximum value of engine boost pressure, and

limiting fuel supplied to the engine as a function of the limit value.

9. The method of claim 2 wherein determining a maximum value of an operating parameter comprises:

measuring engine exhaust temperature, and

determining a maximum value of engine boost pressure as a function of the inlet density of the compressor of the turbocharger and also as a function of the measured engine exhaust temperature.

10. The method of claim 9 wherein measuring engine exhaust temperature comprises:

measuring a cylinder exhaust temperature produced by each cylinder of the engine, and

computing an average of the measured cylinder exhaust temperatures.

11. The method of claim 9 wherein measuring exhaust temperature comprises determining a stack temperature corresponding to a temperature of exhaust gas flowing through the one or more exhaust manifolds.

12. The method of claim 9 wherein measuring a value of the operating parameter comprises measuring engine boost pressure.

13. The method of claim 12 wherein limiting fuel supplied to the engine comprises:

determining an engine acceleration value,

determining a limit value as a function of the error value and of the engine acceleration value in a manner that limits the engine boost pressure to the maximum value of engine boost pressure, and

limiting fuel supplied to the engine as a function of the limit value.

14. The method of claim 2 wherein determining a maximum value of an operating parameter comprises determining a maximum value of engine exhaust temperature as a function of the inlet density of the compressor of the turbocharger,

and wherein measuring a value of the operating parameter comprises measuring engine exhaust temperature.

15. The method of claim 14 wherein measuring engine exhaust temperature comprises:

measuring a cylinder exhaust temperature produced by each cylinder of the engine, and

computing an average of the measured cylinder exhaust temperatures.

16. The method of claim 15 wherein determining a maximum value of engine exhaust temperature comprises determining a maximum value of average exhaust temperature as a function of the inlet density of the compressor of the turbocharger, the maximum value of average exhaust temperature corresponding to a maximum value of the average of the cylinder exhaust temperatures.

17. The method of claim 14 wherein limiting fuel supplied to the engine comprises:

determining an engine acceleration value,

determining a limit value as a function of the error value and of the engine acceleration value in a manner that limits the engine exhaust temperature to the maximum value of engine exhaust temperature, and

limiting fuel supplied to the engine as a function of the limit value.

18. A method for controlling fueling of an internal combustion engine, the engine including a turbocharger having a compressor fluidly coupled to an intake manifold of the engine and a turbine fluidly coupled to one or more exhaust manifolds of the engine, the method comprising:

determining ambient pressure,

estimating an inlet density of the turbocharger compressor as a function of the ambient pressure,

measuring rotational speed of the turbocharger,

determining a first maximum value of engine boost pressure as a function of the inlet density of the turbocharger compressor and of the rotational speed of the turbocharger,

measuring engine exhaust temperature,

determining a second maximum value of engine boost pressure as a function of the inlet density of the turbocharger compressor and of the engine exhaust temperature,

measuring engine boost pressure,

determining an error value as a function of a minimum of the first maximum value of engine boost pressure and the second maximum value of engine boost pressure and also as a function of the measured engine boost pressure, and

limiting fuel supplied to the engine based on the error value.

19. The method of claim 18 wherein measuring engine exhaust temperature comprises:

measuring a cylinder exhaust temperature produced by each cylinder of the engine, and

computing an average of the measured cylinder exhaust temperatures.

20. The method of claim 18 wherein measuring exhaust temperature comprises determining a stack temperature corresponding to a temperature of exhaust gas flowing through the one or more exhaust manifolds.

21. The method of claim 18 wherein limiting fuel supplied to the engine comprises:

determining an engine acceleration value,

determining a limit value as a function of the error value and of the engine acceleration value in a manner that limits the engine boost pressure to the minimum of the first and second maximum values of engine boost pressure, and

limiting fuel supplied to the engine as a function of the limit value.

22. A method for controlling fueling of an internal combustion engine, the engine including a turbocharger having a compressor fluidly coupled to an intake manifold of the engine and a turbine fluidly coupled to one or more exhaust manifolds of the engine, the method comprising:

determining ambient pressure,

estimating an inlet density of the turbocharger compressor as a function of the ambient pressure,

measuring rotational speed of the turbocharger,

determining a first maximum value of engine boost pressure as a function of the inlet density of the turbocharger compressor and of the rotational speed of the turbocharger,

measuring engine exhaust temperature,

determining a second maximum value of engine boost pressure as a function of the inlet density of the turbocharger compressor and of the engine exhaust temperature,

measuring engine boost pressure,

determining a first error value as a function of a minimum of the first maximum value of engine boost pressure and the second maximum value of engine boost pressure and also as a function of the measured engine boost pressure,

determining a maximum value of rotational speed of the turbocharger as a function of the inlet density of the turbocharger compressor,

determining a second error value as a function of the maximum value of rotational speed of the turbocharger and of the measured rotational speed of the turbocharger,

determining a maximum value of engine exhaust temperature as a function of the inlet density of the turbocharger compressor,

determining a third error value as a function of the maximum value of engine exhaust temperature and of the measured engine exhaust temperature, and

limiting fuel supplied to the engine based on a minimum of the first, second and third error values.

23. The method of claim 22 wherein limiting fuel supplied to the engine comprises:

determining an engine acceleration value,

determining a limit value as a function of the minimum of the first, second and third error values and of the engine acceleration value, and

limiting fuel supplied to the engine as a function of the limit value.

24. A method for controlling fueling of an internal combustion engine, the engine including a fuel system having at least one fuel injector and a turbocharger having a compressor fluidly coupled to an intake manifold of the engine and a turbine fluidly coupled to at least one exhaust manifold of the engine, the method comprising:

determining a fuel quantity to inject into the engine via the at least one fuel injector,

mapping the determined fuel quantity to at least one injector on-time,

determining a fuel limit value as a function of one or more of a difference between a maximum turbocharger speed and a measured turbocharger speed, a difference between a maximum boost pressure and a measured boost pressure and a difference between a maximum engine exhaust temperature and a measured engine exhaust temperature, and

reducing the at least one injector on-time if the fuel limit value exceeds a threshold fuel value for at least a predetermined time period.

25. The method of claim 24 wherein reducing the at least one injector on-time comprises reducing the at least one injector on-time by a predetermined time value.

26. The method of claim 25 wherein the engine further includes an ignition key that is in an on state when the engine is running and is in an off state when the engine is not running,

and wherein reducing the at least one injector on-time comprises reducing the at least one injector on-time by the predetermined time value each time the ignition key transitions from its off state to its on state if the fuel limit value exceeds a threshold fuel value for at least a predetermined time period.

27. The method of claim 26 further comprising:

determining a change in the at least one injector on-time, and

activating an error flag if the change in the at least one injector on-time exceeds a threshold value.

28. The method of claim 26 further comprising:

determining a change in the at least one injector on-time, and

activating visual indicator if the change in the at least one injector on-time exceeds a threshold value.

29. The method of claim 26 wherein reducing the at least one injector on-time further comprises limiting reduction of the at least one injector on-time to a minimum reduction value.

30. The method of claim 26 wherein the engine includes an intake manifold pressure sensor configured to produce the measured boost pressure value and an ambient pressure sensor,

and wherein the method further comprises:

determining whether the intake manifold pressure sensor has failed, and

determining whether the ambient pressure sensor has failed,

and wherein reducing the at least one injector on-time comprises reducing the at least one injector on-time if the fuel limit value exceeds the threshold fuel value for at least the predetermined time period only if the intake manifold pressure sensor has not failed and the ambient pressure sensor has not failed.

31. The method of claim 30 further comprising maintaining the at least one injector on-time if at least one of the intake manifold pressure sensor has not failed and the ambient pressure sensor has not failed.

32. The method of claim 24 further comprising limiting the determined fuel quantity to the fuel limit value prior to mapping the determined fuel quantity to at least one injector on-time.

33. A method for controlling fueling of an internal combustion engine, the engine including a fuel system having at least one fuel injector and a turbocharger having a compressor fluidly coupled to an intake manifold of the engine and a turbine fluidly coupled to at least one exhaust manifold of the engine, the method comprising:

measuring engine rotational speed,

determining a maximum engine output torque of the engine as a function of the measured engine rotational speed,

determining a fuel limit value as a function of one or more of a difference between a maximum turbocharger speed and a measured turbocharger speed, a difference between a maximum boost pressure and a measured boost pressure and a difference between a maximum engine exhaust temperature and a measured engine exhaust temperature,

determining a fueling growth derate amount as a function of the fuel limit value and the maximum engine output torque if engine fueling is being limited by the fuel limit value, and

activating an error flag if the fueling growth derate amount is greater than a threshold value.

34. The method of claim 33 further comprising activating visual indicator if the fueling growth derate amount is greater than the threshold value.