Fuel control system for limiting turbocharger speed

• US 20090293476A1
• Filed: 05/30/2008
• Published: 12/03/2009
• Est. Priority Date: 05/30/2008
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Evans, Raymond Geraint
• Granted Patent: US 8,061,137 B2
• Time in Patent Office: Days
• US Class Current: 60/602
• CPC Class Codes: F02D 23/00 Controlling engines characterised by their being supercharged
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A method is provided for operating a turbocharger. The method includes sensing a parameter indicative of a speed of a turbocharger and a parameter indicative of an engine speed. The method also includes determining a first desired engine speed based on the speed of the turbocharger, the engine speed, and a maximum desired speed of the turbocharger. The method further includes regulating a flow of fuel to an engine based on the first desired engine speed.

Claims

1. A method for operating a turbocharger, comprising:

sensing a parameter indicative of a speed of the turbocharger;

sensing a parameter indicative of an engine speed;

determining a first desired engine speed based on the speed of the turbocharger, the engine speed, and a maximum desired speed of the turbocharger; and

regulating a flow of fuel to an engine based on the first desired engine speed.

2. The method of claim 1, wherein determining the first desired engine speed further includes multiplying the engine speed by a ratio, the ratio being a relation between the maximum desired speed of the turbocharger and the speed of the turbocharger.

3. The method of claim 2, wherein regulating the flow of fuel to the engine further includes comparing the first desired engine speed to a second desired engine speed and regulating the flow of fuel to the engine based on the desired engine speed having a lower value, the second desired engine speed being based on a desired throttle setting of the engine.

4. The method of claim 3, further including modifying the ratio before determining the first desired engine speed so that when the regulation of the flow of fuel to the engine is based on the first desired engine speed, the speed of the turbocharger is overdamped.

5. The method of claim 4, further including modifying the engine speed to increase the likelihood that the regulation of the flow of fuel to the engine is based on the first desired engine speed when the engine speed is accelerating.

6. The method of claim 5, further including determining a first desired engine fuel rate based on the first and second desired engine speeds.

7. The method of claim 6, wherein regulating the flow of fuel to the engine further includes comparing the first desired engine fuel rate and a second desired engine fuel rate and regulating the flow of fuel to the engine based on the fueling rate having a lower value, the second desired engine fuel rate being based on fuel limiting methods performed independently of the rotational speed of the turbocharger.

8. The method of claim 1, wherein the maximum desired speed of the turbocharger is an overspeed limit of the turbocharger.

9. A method for operating a plurality of turbochargers, comprising:

sensing a parameter indicative of a speed of each turbocharger;

sensing a parameter indicative of an engine speed;

determining a first desired engine speed based on the speeds of the plurality of turbochargers, the engine speed, and maximum desired speeds of each turbocharger; and

regulating a flow of fuel to an engine based on the first desired engine speed.

10. The method of claim 9, further including selecting a turbocharger speed from a plurality of turbocharger speeds, the selected turbocharger speed being a speed of the turbocharger operating closest to its maximum desired speed.

11. The method of claim 10, wherein determining the first desired engine speed further includes multiplying the engine speed by a ratio, the ratio being a relation between the maximum desired speed of the turbocharger associated with the selected turbocharger speed and the selected turbocharger speed.

12. The method of claim 11, wherein regulating the flow of fuel to the engine further includes comparing the first desired engine speed to a second desired engine speed and regulating the flow of fuel to the engine based on the desired engine speed having a lower value, the second desired engine speed being based on a desired throttle setting of the engine.

13. The method of claim 12, further including modifying the ratio before determining the first desired engine speed so that when the regulation of the flow of fuel to the engine is based on the first desired engine speed, the speed of the turbocharger is overdamped.

14. The method of claim 13, further including modifying the engine speed to increase the likelihood that the regulation of the flow of fuel to the engine is based on the first desired engine speed when the engine speed is accelerating.

15. The method of claim 14, further including determining a first desired engine fuel rate based on the first and second desired engine speeds.

16. The method of claim 15, wherein regulating the flow of fuel to the engine further includes comparing the first desired engine fuel rate and a second desired engine fuel rate and regulating the flow of fuel to the engine based on the fueling rate having a lower value, the second desired engine fuel rate being based on fuel limiting methods performed independently of the rotational speed of the turbocharger.

17. The method of claim 9, wherein the maximum desired speed of the turbocharger is an overspeed limit of the turbocharger.

18. A power system, comprising:

an engine;

a fuel system situated to supply fuel to the engine;

at least one turbocharger situated to supply charged air to the engine; and

a controller configured to regulate the rate of fuel being supplied to the engine based on a first parameter indicative of a speed of the at least one turbocharger, a second parameter indicative of an engine speed, and a maximum desired speed of the at least one turbocharger.

19. The power system of claim 18, wherein the controller is configured to regulate the rate of fuel being supplied to the engine based on a comparison between a first desired engine speed determined from a desired position of a throttle of the engine and a second desired engine speed based on the speed of the at least one turbocharger, the engine speed, and the maximum desired speed of the at least one turbocharger.

20. The power system of claim 18, wherein the maximum desired speed of the at least one turbocharger is an overspeed limit of the at least one turbocharger.