Granted Patent B2

US 7,950,371 · App. 12/424,175 · Granted May 31, 2011

Abstract

Claims (30)

1. A control system comprising:

a fuel pump control module that controls a fuel pump to provide fuel to a fuel rail;

a fuel injection control module that selectively suspends fuel injection from the fuel rail based on vehicle operating conditions; and

a diagnostic module that controls the fuel pump control module to provide a predetermined amount of fuel to the fuel rail when fuel injection from the fuel rail is suspended based on the vehicle operating conditions, that determines an estimated pressure increase within the fuel rail based on the predetermined amount of fuel, that compares an actual pressure increase within the fuel rail to the estimated pressure increase, and that selectively diagnoses a fault in the fuel pump based on the comparison.

2. The control system of claim 1 wherein the diagnostic module determines the estimated pressure increase within the fuel rail based on a mathematical model.

3. The control system of claim 2 wherein the mathematical model includes an expression that relates the estimated pressure increase to a fuel bulk modulus, a fuel density, a fuel rail volume, and the predetermined amount of fuel.

4. The control system of claim 1 wherein the diagnostic module calculates a compensation factor based on the comparison.

5. The control system of claim 4 wherein the diagnostic module calculates the compensation factor based on a difference between the estimated pressure increase and the actual pressure increase.

6. The control system of claim 4 wherein the diagnostic module sets a service indicator when the compensation factor is greater than or equal to a predetermined threshold.

7. The control system of claim 4 further comprising a compensation module that selectively generates a compensated pressure signal based on the compensation factor and a desired pressure, and wherein the fuel pump control module selectively controls the fuel pump based on the compensated pressure signal.

8. The control system of claim 7 wherein the fuel pump control module suspends controlling based on the compensated pressure signal and controls based on the desired pressure when the actual pressure increase is greater than or equal to the estimated pressure increase.

9. A method comprising:

selectively suspending fuel injection from a fuel rail based on vehicle operating conditions;

controlling a fuel pump to provide a predetermined amount of fuel to the fuel rail when fuel injection from the fuel rail is suspended based on the vehicle operating conditions;

determining an estimated pressure increase within the fuel rail based on the predetermined amount of fuel;

comparing an actual pressure increase within the fuel rail to the estimated pressure increase; and

selectively diagnosing a fault in the fuel pump based on the comparison.

10. The method of claim 9 further comprising determining the estimated pressure increase within the fuel rail based on a mathematical model.

11. The method of claim 10 wherein the mathematical model includes an expression that relates the estimated pressure increase to a fuel bulk modulus, a fuel density, a fuel rail volume, and the predetermined amount of fuel.

12. The method of claim 9 further comprising calculating a compensation factor based on the comparison.

13. The method of claim 12 further comprising calculating the compensation factor based on a difference between the estimated pressure increase and the actual pressure increase.

14. The method of claim 12 further comprising setting a service indicator when the compensation factor is greater than or equal to a predetermined threshold.

15. The method of claim 12 further comprising:

selectively generating a compensated pressure signal based on the compensation factor and a desired pressure; and

selectively controlling the fuel pump based on the compensated pressure signal.

16. The method of claim 15 further comprising, when the actual pressure increase is greater than or equal to the estimated pressure increase, controlling based on the desired pressure and suspending the controlling based on the compensated pressure signal.

17. The control system of claim 1 , wherein the fuel pump control module selectively controls the fuel pump based on the comparison.

18. The method of claim 9 , further comprising selectively controlling the fuel pump based on the comparison.

19. The control system of claim 1 , wherein the fuel injection control module suspends fuel injection from the fuel rail during at least one of a coasting event and a braking event.

20. The method of claim 9 , further comprising suspending fuel injection from the fuel rail during at least one of a coasting event and a braking event.

Assignments (8)