Engine speed based valvetrain control systems and methods

1. A system for a vehicle, comprising:

a trigger module that generates a trigger when an engine speed is greater than a first predetermined speed, wherein the first predetermined speed is greater than zero;

a fuel control module that cuts off fuel to cylinders of the engine in response to the generation of the trigger; and

a cylinder control module that selectively disables opening of intake and exhaust valves of the cylinders in response to the generation of the trigger after the fuel is cut off.

2. The system of claim 1 wherein the cylinder control module disables opening of the intake and exhaust valves of one of the cylinders starting at a time between an intake stroke of a combustion cycle of the one of the cylinders and an exhaust stroke of the combustion cycle of the one of the cylinders.

3. The system of claim 1 wherein the cylinder control module enables opening of the intake and exhaust valves of a first one of the cylinders when the engine speed is less than a second predetermined speed, and

wherein the second predetermined speed is less than the first predetermined speed.

4. The system of claim 3 wherein the cylinder control module enables opening of the intake and exhaust valves of the first one of the cylinders starting at a time between an intake stroke of a first combustion cycle of the first one of the cylinders and an exhaust stroke of the first combustion cycle of the first one of the cylinders.

5. The system of claim 4 wherein the fuel control module starts providing fuel to the cylinder during a second combustion cycle that follows the first combustion cycle.

6. The system of claim 3 wherein, at least a predetermined period after opening of the intake and exhaust valves of the first one of the cylinders is enabled, enables the intake and exhaust valves of a second one of the cylinders when the engine speed is less than the second predetermined speed.

7. The system of claim 6 wherein the predetermined period is at least two combustion cycles.

8. The system of claim 3 wherein, at least a predetermined period after opening of the intake and exhaust valves of the first one of the cylinders is enabled, the fuel control module cuts off fuel to the engine when the engine speed is greater than a third predetermined speed, and

wherein the third predetermined speed is greater than the first predetermined speed.

9. The system of claim 8 wherein the cylinder control module enables opening of the exhaust valves of the cylinders based on a predetermined lift when the engine speed is greater than the third predetermined speed.

10. The system of claim 8 wherein, when the engine speed is greater than the third predetermined speed, the cylinder control module enables opening of an exhaust valve of a second one of the cylinders when a volume within the second one of the cylinders is increasing and disables opening of the exhaust valve when the volume within the second one of the cylinders is decreasing.

11. A method for a vehicle, comprising:

generating a trigger when an engine speed is greater than a first predetermined speed,

wherein the first predetermined speed is greater than zero;

cutting off fuel to cylinders of the engine in response to the generation of the trigger; and

selectively disabling opening of intake and exhaust valves of the cylinders in response to the generation of the trigger after the fuel is cut off.

12. The method of claim 11 further comprising disabling opening of the intake and exhaust valves of one of the cylinders starting at a time between an intake stroke of a combustion cycle of the one of the cylinders and an exhaust stroke of the combustion cycle of the one of the cylinders.

13. The method of claim 11 further comprising enabling opening of the intake and exhaust valves of a first one of the cylinders when the engine speed is less than a second predetermined speed,

wherein the second predetermined speed is less than the first predetermined speed.

14. The method of claim 13 further comprising enabling opening of the intake and exhaust valves of the first one of the cylinders starting at a time between an intake stroke of a first combustion cycle of the first one of the cylinders and an exhaust stroke of the first combustion cycle of the first one of the cylinders.

15. The method of claim 14 further comprising starting providing fuel to the cylinder during a second combustion cycle that follows the first combustion cycle.

16. The method of claim 13 further comprising, at least a predetermined period after opening of the intake and exhaust valves of the first one of the cylinders is enabled, enabling the intake and exhaust valves of a second one of the cylinders when the engine speed is less than the second predetermined speed.

17. The method of claim 16 wherein the predetermined period is at least two combustion cycles.

18. The method of claim 13 further comprising, at least a predetermined period after opening of the intake and exhaust valves of the first one of the cylinders is enabled, cutting off fuel to the engine when the engine speed is greater than a third predetermined speed,

wherein the third predetermined speed is greater than the first predetermined speed.

19. The method of claim 18 further comprising enabling opening of the exhaust valves of the cylinders based on a predetermined lift when the engine speed is greater than the third predetermined speed.

20. The method of claim 18 further comprising, when the engine speed is greater than the third predetermined speed:

enabling opening of an exhaust valve of a second one of the cylinders when a volume within the second one of the cylinders is increasing; and

disabling opening of the exhaust valve when the volume within the second one of the cylinders is decreasing.