System and method for detecting fuel injector malfunction based on engine vibration

1. A control system for an engine, comprising:

an injection control module that commands a fuel injector to operate in a split injection mode;

a processing module that measures engine vibration during a period after commanding the split injection mode; and

a malfunction detection module that detects a malfunction of the fuel injector based on a comparison between the measured engine vibration and expected engine vibration.

2. The control system of claim 1 , wherein the split injection mode includes both a pilot injection and a main injection during each combustion cycle.

3. The control system of claim 1 , wherein the malfunction detection module detects a malfunction of the fuel injector when the measured engine vibration is less than the expected engine vibration.

4. The control system of claim 1 , wherein when the malfunction of the fuel injector is detected, the malfunction detection module at least one of generates an error signal and determines a parameter of the fuel injector.

5. The control system of claim 4 , wherein the parameter of the fuel injector is one of an estimation and a determination of a flow rate of the fuel injector based on a difference between the expected engine vibration and the measured engine vibration.

6. The control system of claim 5 , wherein the injection control module modifies fuel injection based on the estimated or determined flow rate.

7. The control system of claim 1 , wherein the measured engine vibration is measured by an engine knock sensor or an accelerometer, and wherein the measured engine vibration has an intensity and a frequency.

8. The control system of claim 7 , wherein the processing module determines the intensity based on a maximum of the measured engine vibration during a period.

9. The control system of claim 7 , wherein the processing module determines the frequency based on a maximum of a fast Fourier transform (FFT) of the measured engine vibration.

10. The control system of claim 1 , wherein the expected engine vibration is based on predetermined engine vibration associated with properly functioning fuel injectors.

11. A method for controlling an engine, comprising:

commanding a fuel injector to operate in a split injection mode;

measuring engine vibration during a period after commanding the split injection mode; and

detecting a malfunction of the fuel injector based on a comparison between the measured engine vibration and expected engine vibration.

12. The method of claim 11 , wherein the split injection mode includes both a pilot injection and a main injection during each combustion cycle.

13. The method of claim 11 , wherein a malfunction of the fuel injector is detected when the measured engine vibration is less than the expected engine vibration.

14. The method of claim 11 , further comprising:

when the malfunction of the fuel injector is detected, at least one of generating an error signal and determining a parameter of the fuel injector.

15. The method of claim 14 , wherein the parameter of the fuel injector is one of an estimation and a determination of a flow rate of the fuel injector based on a difference between the expected engine vibration and the measured engine vibration.

16. The method of claim 15 , further comprising modifying fuel injection based on the estimated or determined flow rate.

17. The method of claim 11 , further comprising measuring engine vibration using an engine knock sensor or an accelerometer, wherein the measured engine vibration has an intensity and a frequency.

18. The method of claim 17 , further comprising determining the intensity based on a maximum of the measured engine vibration during a period.

19. The method of claim 17 , further comprising determining the frequency based on a maximum of a fast Fourier transform (FFT) of the measured engine vibration.

20. The method of claim 11 , wherein the expected engine vibration is based on predetermined engine vibration associated with properly functioning fuel injectors.