Granted Patent B2

US 7,963,268 · App. 12/400,022 · Granted Jun 21, 2011

Abstract

Claims (55)

1. Method for controlling a spark-ignition direct injection internal combustion engine including a controllable valvetrain having intake and exhaust valves, and a controllable intake air throttle valve, the method comprising:

commanding engine operation to transition between a controlled auto-ignition combustion mode and a homogeneous spark-ignition combustion mode; and

operating the engine in a stratified-charge spark-ignition combustion mode during said transition, wherein operating in the stratified-charge spark-ignition combustion mode comprises:

controlling the valve cam phasing and variable lift control devices;

injecting a fuel pulse during a compression stroke sufficient to power the engine; and

executing a spark discharge immediately subsequent to the injected fuel pulse.

2. The method of claim 1 , further comprising:

monitoring an engine operating point; and

commanding engine operation to transition to a preferred one of the controlled auto-ignition combustion mode and the homogeneous spark-ignition combustion mode based on the engine operating point.

3. The method of claim 2 , further comprising commanding the engine operation to transition to the preferred one of the controlled auto-ignition combustion mode and the homogeneous spark-ignition combustion mode when the engine operating point corresponds to an engine operating zone associated therewith.

4. The method of claim 2 , further comprising:

associating the controlled auto-ignition combustion mode with a first engine operating zone;

associating the homogeneous spark-ignition combustion mode with a second engine operating zone;

operating the engine in the controlled auto-ignition when the engine operating point corresponds to the first engine operating zone; and

commanding engine operation to transition to the homogeneous spark-ignition combustion mode when the engine operating point transitions from the first to the second engine operating zone.

5. The method of claim 4 , further comprising:

operating the engine in the homogeneous spark ignition combustion mode when the engine operating point corresponds to the second engine operating zone; and

commanding engine operation to transition to the controlled auto-ignition combustion mode when the engine operating point transitions from the second engine operating zone to the first engine operating zone.

6. The method of claim 1 , wherein the stratified-charge spark-ignition combustion mode further comprises:

estimating a cylinder air charge determined from operation in the selected combustion mode; and

controlling the intake air throttle valve based upon the estimated cylinder air charge.

7. The method of claim 1 , wherein a transition to the controlled auto-ignition combustion mode from the homogeneous spark-ignition combustion mode comprises:

opening the throttle valve;

controlling the intake and exhaust valves to a negative valve overlap; and

controlling the intake valves from a high lift to a low lift.

8. The method of claim 7 , wherein the controllable valvetrain further includes a variable cam phasing mechanism, and wherein controlling the intake and exhaust valves to a negative valve overlap comprises controlling the variable cam phasing mechanism.

9. The method of claim 7 , wherein the controllable valvetrain further includes a two-step variable lift control mechanism, and wherein controlling the intake valves from a high lift to a low lift comprises controlling the two-step variable lift control mechanism.

10. The method of claim 7 , further comprising:

operating the engine in the stratified-charge spark-ignition combustion mode immediately subsequent to commanding engine operation to transition to the controlled auto-ignition combustion mode.

11. The method of claim 1 , wherein a transition to the homogeneous spark-ignition combustion mode from the controlled auto-ignition combustion mode comprises:

controlling the throttle valve to achieve a predetermined position;

controlling the intake and exhaust valves to a positive valve overlap; and

controlling the intake valves from a low lift to a high lift.

12. The method of claim 11 , wherein the controllable valvetrain further includes a variable cam phasing mechanism, and wherein controlling the intake and exhaust valves to a positive valve overlap comprises controlling the variable cam phasing mechanism.

13. The method of claim 11 , wherein the controllable valvetrain further includes a two-step variable lift control mechanism, and wherein controlling the intake valves from a low lift to a high lift comprises controlling the two-step variable lift control mechanism.

14. The method of claim 11 , further comprising:

operating the engine in the stratified-charge spark-ignition combustion mode subsequent to controlling the intake valves from a low lift to a high lift.

15. The method of claim 1 , further comprising:

monitoring intake airflow; and

operating the engine in the stratified-charge spark-ignition combustion mode during a transition when the intake airflow exceeds a predetermined threshold and discontinuing operating the engine in the stratified-charge spark-ignition combustion mode when the intake airflow recedes from the predetermined threshold.

16. Method for controlling a spark-ignition direct injection internal combustion engine configured to operate in one of a controlled auto-ignition combustion mode and a homogeneous spark-ignition combustion mode, comprising:

operating in an initial combustion mode comprising one of the controlled auto-ignition combustion mode and the homogeneous spark-ignition combustion mode;

monitoring an engine operating point;

determining a preferred combustion mode corresponding to the engine operating point;

commanding engine operation to transition from the initial combustion mode to the preferred combustion mode when the preferred combustion mode is not the initial combustion mode; and

operating the engine in a stratified-charge spark-ignition combustion mode during the transition to the preferred combustion mode, wherein operating in the stratified-charge spark-ignition combustion mode comprises:

estimating a cylinder air charge determined from operation in the preferred combustion mode;

controlling a throttle valve, valve cam phasing device, and variable lift control device based upon the estimated cylinder air charge;

injecting a fuel pulse during a compression stroke sufficient to power the engine; and

executing a spark discharge at or immediately subsequent to the injected fuel pulse.

17. The method of claim 16 , further comprising:

adjusting an intake airflow during the transition from the initial combustion mode to the preferred combustion mode; and

invoking operating in the stratified-charge spark-ignition combustion mode from the initial combustion mode when the intake airflow is within a predetermined airflow range.

18. The method of claim 17 , further comprising:

invoking operating in the preferred combustion mode from the stratified-charge spark-ignition combustion mode when the intake airflow is outside the predetermined airflow range.

Assignments (8)