Systems and methods for decreasing torque fluctuations during cylinder deactivation and reactivation

1. A control system for an engine, the control system comprising:

an engine module that determines whether M of N cylinders of the engine are to be deactivated or reactivated, where M is an integer greater than or equal to one, and where N is an integer greater than M;

a first spark control module that, based on the engine module determining the M cylinders of the engine are to be deactivated or reactivated, retards spark timing for the M cylinders of the engine to a first spark timing during a period before the deactivating or after the reactivating of the M cylinders of the engine; and

a second spark control module that, based on the engine module determining the M cylinders of the engine are to be deactivated or reactivated, advances spark timing for N−M active cylinders of the engine to a second desired spark timing during the period before the deactivating or after the reactivating of the M cylinders of the engine, wherein the second spark timing is more advanced than the first spark timing.

2. The control system of claim 1 , further comprising a torque split module that determines, based on a base torque request, a torque split value for the M cylinders of the engine and the N−M active cylinders of the engine.

3. The control system of claim 2 , wherein:

the torque split module determines the torque split value based on a plurality of operating parameters; and

the plurality of operating parameters include minimum and maximum torque capacities at minimum and maximum spark advances allowed at current operating conditions, respectively.

4. The control system of claim 1 , further comprising a torque split module that determines, based on a base torque request, a minimum torque capacity, and a maximum torque capacity, a torque split value for the M cylinders of the engine and the N−M active cylinders of the engine, wherein the torque split value is a lesser of:

(1) a product of (i) a difference between the base torque request and the minimum torque capacity and (ii) a quotient of M and N−M; and

(2) a difference between the maximum torque capacity and the base torque request.

5. The control system of claim 2 , wherein the torque split module determines a first torque request for the M cylinders of the engine based on a difference between the base torque request and a product of (i) the torque split value and (ii) a quotient of N−M and M.

6. The control system of claim 5 , wherein the first spark control module determines the first spark timing based on the first torque request.

7. The control system of claim 4 , wherein the torque split module determines a second torque request for the N−M active cylinders of the engine based on a sum of the base torque request and the torque split value.

8. The control system of claim 7 , wherein the second spark control module determines the second spark timing based on the second torque request.

9. The control system of claim 1 , wherein N equals a total number of cylinders in the engine, and wherein M equals one half of N.

10. The control system of claim 1 , wherein the engine is coupled to a manual transmission.

11. A method for controlling an engine, the method comprising:

determining whether M of N cylinders of the engine are to be deactivated or reactivated, where M is an integer greater than or equal to one, and where N is an integer greater than M;

based on determining the M cylinders of the engine are to be deactivated or reactivated, retarding spark timing for the M cylinders of the engine to a first spark timing during a period before the deactivating or after the reactivating of the M cylinders of the engine; and

based on determining the M cylinders of the engine are to be deactivated or reactivated, advancing spark timing for N−M active cylinders of the engine to a second desired spark timing during the period before the deactivating or after the reactivating of the M cylinders of the engine, wherein the second spark timing is more advanced than the first spark timing.

12. The method of claim 11 , further comprising determining a torque split value for the M cylinders of the engine and the N−M active cylinders of the engine based on a base torque request.

13. The method of claim 12 , wherein:

the torque split value is determined based on a plurality of operating parameters; and

the plurality of operating parameters include minimum and maximum torque capacities at minimum and maximum spark advances allowed at current operating conditions, respectively.

14. The method of claim 11 , further comprising determining a torque split value for the M cylinders of the engine and the N−M active cylinders of the engine based on a base torque request, a minimum torque capacity, and a maximum torque capacity, wherein the torque split value is a lesser of:

(1) a product of (i) a difference between the base torque request and the minimum torque capacity and (ii) a quotient of M and N−M; and

(2) a difference between the maximum torque capacity and the base torque request.

15. The method of claim 12 , further comprising determining a first torque request for the M cylinders of the engine based on a difference between the base torque request and a product of (i) the torque split and (ii) a quotient of N−M and M.

16. The method of claim 15 , further comprising determining the first spark timing based on the first torque request.

17. The method of claim 14 , further comprising determining a second torque request for the N−M active cylinders of the engine based on a sum of the base torque request and the torque split value.

18. The method of claim 17 , further comprising determining the second spark timing based on the second torque request.

19. The method of claim 11 , wherein N equals a total number of cylinders in the engine, and wherein M equals one half of N.

20. The method of claim 11 , wherein the engine is coupled to a manual transmission.