System and method for controlling a firing sequence of an engine to reduce vibration when cylinders of the engine are deactivated

1. A system comprising:

a vibration prediction module that predicts a vibration response of a vehicle based on a firing sequence of an engine when a cylinder of the engine is deactivated; and

a firing sequence module that adjusts the firing sequence of the engine based on the predicted vibration response of the vehicle.

2. The system of claim 1 wherein the vibration prediction module predicts the vibration response based on torque pulses of firing cylinders and non-firing cylinders in the firing sequence.

3. The system of claim 2 wherein the vibration prediction module:

predicts the vibration response for each torque pulse;

determines the timing of the vibration response for each torque pulse; and

sums portions of the vibration responses that overlap in time to yield the vibration response of the firing sequence.

4. The system of claim 2 further comprising a torque pulse module that estimates the torque pulses based on a pressure within an intake manifold of the engine and engine speed.

5. The system of claim 2 wherein the vibration prediction module predicts the vibration response of each torque pulse based on a predetermined relationship between crankshaft torque and vehicle vibration.

6. The system of claim 5 wherein the predetermined relationship includes an impulse response function.

7. The system of claim 1 wherein:

the vibration prediction module predicts the vibration response of the vehicle corresponding to multiple firing sequence options; and

the firing sequence module selects one of the firing sequence options based on the predicted vibration response of the vehicle.

8. The system of claim 7 wherein the firing sequence module determines the firing sequence options based on a quantity of active cylinders that satisfies a driver torque request.

9. The system of claim 7 wherein the vibration prediction module:

determines a first vibration response for a previous firing sequence;

predicts a second vibration response for each of the firing sequence options;

determines a total vibration response for each of the firing sequence options based on the first vibration response and the corresponding second vibration response; and

selects one of the firing sequence options based on the total vibration response.

10. The system of claim 9 wherein the vibration prediction module determines the total vibration response for each of the firing sequence options by:

determining the timing of the first vibration response and the corresponding second vibration response; and

summing portions of the first vibration response and the corresponding second vibration response that overlap in time.

11. A method comprising:

predicting a vibration response of a vehicle based on a firing sequence of an engine when a cylinder of the engine is deactivated; and

adjusting the firing sequence of the engine based on the predicted vibration response of the vehicle.

12. The method of claim 11 further comprising predicting the vibration response based on torque pulses of firing cylinders and non-firing cylinders in the firing sequence.

13. The method of claim 12 further comprising:

predicting the vibration response for each torque pulse;

determining the timing of the vibration response for each torque pulse; and

summing portions of the vibration responses that overlap in time to yield the vibration response of the firing sequence.

14. The method of claim 12 further comprising estimating the torque pulses based on a pressure within an intake manifold of the engine and engine speed.

15. The method of claim 12 further comprising predicting the vibration response of each torque pulse based on a predetermined relationship between crankshaft torque and vehicle vibration.

16. The method of claim 15 wherein the predetermined relationship includes an impulse response function.

17. The method of claim 11 further comprising:

predicting the vibration response of the vehicle corresponding to multiple firing sequence options; and

selecting one of the firing sequence options based on the predicted vibration response of the vehicle.

18. The method of claim 17 further comprising determining the firing sequence options based on a quantity of active cylinders that satisfies a driver torque request.

19. The method of claim 17 further comprising:

determining a first vibration response for a previous firing sequence;

predicting a second vibration response for each of the firing sequence options;

determining a total vibration response for each of the firing sequence options based on the first vibration response and the corresponding second vibration response; and

selecting one of the firing sequence options based on the total vibration response.

20. The method of claim 19 further comprising determining the total vibration response for each of the firing sequence options by:

determining the timing of the first vibration response and the corresponding second vibration response; and

summing portions of the first vibration response and the corresponding second vibration response that overlap in time.