Methods and system for aging compensation of a fuel system

Patent metadata

Field	Value
Publication number	US-10260446-B2
Application number	US-201615215620-A
Country	US
Kind code	B2
Filing date	Jul 21, 2016
Priority date	Jul 21, 2016
Publication date	Apr 16, 2019
Grant date	Apr 16, 2019

Abstract

Various methods and systems are provided for health assessments of a fuel system. In one example, a fuel system includes a low-pressure pump operable to pump fuel from a fuel source at a first pressure, a high-pressure pump operable to increase the first pressure to a second pressure, a valve positioned between the low-pressure pump and the high-pressure pump and operable to control fuel flow to the high-pressure pump, a common fuel rail fluidly coupling the high-pressure pump to a plurality of fuel injectors coupled to cylinders of an engine, and a controller. The controller is operable to adjust an amount of valve electrical current supplied to the valve to reach a commanded pressure of the common fuel rail during cylinder firing conditions, the supplied valve electrical current adjusted based on a valve pre-firing correction factor for the valve obtained based on valve electrical current prior to cylinder firing commencing.

First claim

What is claimed is:

1. A fuel system, comprising:
a low-pressure fuel pump operable to pump fuel from a fuel source at a first pressure;
a high-pressure fuel pump operable to increase the first pressure to a second pressure;
a valve positioned between the low-pressure fuel pump and the high-pressure fuel pump, the valve being operable to control fuel flow to the high-pressure fuel pump;
a common fuel rail fluidly coupling the high-pressure fuel pump to a plurality of fuel injectors that is operable to inject fuel to cylinders of an engine; and
a controller operable to:
adjust an amount of valve electrical current supplied to the valve to reach a commanded pressure of the common fuel rail during cylinder firing conditions, the supplied valve electrical current adjusted based on a valve pre-firing correction factor for the valve obtained based on valve electrical current prior to cylinder firing commencing; and
further adjust the amount of valve electrical current supplied to the valve to reach the commanded pressure based on a valve firing correction factor, the valve firing correction factor based on valve electrical current during cylinder firing conditions.

2. The fuel system of claim 1 , wherein the controller is operable to obtain the valve pre-firing correction factor by:
opening the valve until a pre-firing pressure of the common fuel rail is reached;
measuring the valve electrical current at the pre-firing pressure;
determining a first difference between the measured valve electrical current and a predicted valve electrical current, the predicted valve electrical current indicative of a predicted amount of valve electrical current to be supplied to the valve to reach the pre-firing pressure; and
setting the valve pre-firing correction factor as the first difference.

3. The fuel system of claim 2 , wherein the controller is operable to obtain the pre-firing correction factor during an engine start while the engine is rotating but no fuel injection is occurring.

4. The fuel system of claim 2 , wherein the controller is operable to indicate a change in performance of one or more of the valve or high-pressure fuel pump if the first difference is greater than a threshold difference.

5. The fuel system of claim 2 , wherein the controller is operable to obtain the valve firing correction factor during steady state engine operation at a given engine speed, a given engine power, and a given pressure of the common fuel rail.

6. The fuel system of claim 5 , wherein to obtain the valve firing correction factor, the controller is operable to:
measure the valve electrical current at the given engine speed, the given engine power, and the given pressure;
determine a second difference between the measured valve electrical current and the predicted valve electrical current, the predicted valve electrical current defining an amount of valve electrical current predicted to be supplied to the valve to reach the given pressure at the given engine speed; and
set the valve firing correction factor as the second difference.

7. The fuel system of claim 6 , wherein the controller is operable to indicate a change in performance of the fuel system responsive to the second difference being greater than a threshold difference.

8. The fuel system of claim 7 , wherein the controller is operable to adjust one or more engine operating parameters in response to the indication of the change in performance.

9. The fuel system of claim 7 , further comprising an optical sensor positioned to detect a quantity of fuel, wherein the controller is operable to indicate the change in performance responsive to output from the optical sensor.

10. A method for a fuel system for an engine, comprising:
during a no-load condition of the engine while the engine is rotating, determining a first correction factor indicative of a difference between a first predicted position of a valve and a first measured position of the valve, the valve being operable to control fuel flow to a fuel pump that pumps fuel to a common fuel rail of the engine;
during steady state engine operation, determining a second correction factor indicative of a difference between a second predicted position of the valve and a second measured position of the valve, the second predicted position of the valve based on the first correction factor;
responsive to an indication to perform a fuel system test, indicating a change in performance of the fuel system based on a difference between a third measured position of the valve and a threshold position, the threshold position based on both the first correction factor and second correction factor; and
adjusting one or more engine operating parameters responsive to the change in performance of the fuel system.

11. The method of claim 10 , further comprising determining an age of the valve based on a rate of change of the first correction factor over a duration.

12. The method of claim 10 , further comprising determining an age of one or more fuel injectors of the engine based on a rate of change of the second correction factor over a duration.

13. A method for a fuel system for an engine, the fuel system including a valve operable to control fuel flow to a fuel pump that pumps fuel to a common fuel rail of the engine, the method comprising:
indicating a change in performance in the fuel system responsive to valve electrical current of the valve differing from a corrected valve electrical current threshold by more than a threshold amount, the corrected valve electrical current threshold including a base valve electrical current corrected with a first, pre-firing correction factor indicative of valve and/or fuel pump age and a second, firing correction factor indicative of fuel injector age; and
adjusting one or more engine operating parameters responsive to the change in performance of the fuel system.

14. The method of claim 13 , further comprising correcting the base valve electric current with the first, pre-firing correction factor by opening the valve until a pre-firing pressure of the common fuel rail is reached, measuring valve electrical current at the pre-firing pressure, determining a first difference between the measured valve electrical current and the base valve electrical current, and correcting the base valve electrical current based on the first difference to reach a reference valve electrical current.

15. The method of claim 14 , wherein correcting the base valve electric current with the first, pre-firing correction factor comprises correcting the base valve electric current with the first, pre-firing correction factor during an engine start while the engine is rotating but no fuel injection is occurring.

16. The method of claim 14 , further comprising correcting the reference valve electrical current with the second, firing correction factor by measuring the valve electrical current at a given engine speed and a given pressure of the common fuel rail; determining a second difference between the measured valve electrical current at the given engine speed and the given pressure and the reference valve electrical current, and correcting the reference valve electrical current based on the second difference to reach the corrected valve electrical current threshold.

17. The method of claim 16 , wherein correcting the reference valve electrical current with the second firing correction factor comprises correcting the reference valve electrical current with the second firing correction factor during cylinder firing conditions that include steady state engine operation at the given engine

Assignees

• Gen Electric
• Ge Global Sourcing Llc

Inventors

• Ottikkutti Pradheepram
• Chandrashekar Bharath
• Nair Shailesh
• Willis Jeffrey David

Classifications

• F02D2200/0602

  Fuel pressure · CPC title

• F02M59/466

  Electrically operated valves, e.g. using electromagnetic or piezoelectric operating means · CPC title

• F02D2041/2058

  using information of the actual current value · CPC title

• F02D2041/224

  Diagnosis of the fuel system · CPC title

• F02M55/025

  Common rails · CPC title