Method and apparatus to control a transition between HCCI and SI combustion in a direct-injection gasoline engine

• US 20070272202A1
• Filed: 05/17/2007
• Published: 11/29/2007
• Est. Priority Date: 05/25/2006
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Najt, Paul M., Wermuth, Nicole, Kuo, Tang-Wei, Eng, James A.
• Granted Patent: US 7,478,620 B2
• Time in Patent Office: Days
• US Class Current: 123/295
• CPC Class Codes: F01L 1/34 characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
• CPC Class Codes: F01L 13/0015 for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque
• CPC Class Codes: F01L 2001/0537 Double overhead camshafts [DOHC]
• CPC Class Codes: F01L 2013/001 Deactivating cylinders
• CPC Class Codes: F01L 2305/00 Valve arrangements comprising rollers
• CPC Class Codes: F01L 2820/01 Absolute values
• CPC Class Codes: F02B 1/12 with compression ignition with fuel-air charge ignited by compression ignition of an additional fuel F02B7/00
• CPC Class Codes: F02B 2075/125 Direct injection in the combustion chamber for spark ignition engines, i.e. not in pre-combustion chamber
• CPC Class Codes: F02B 23/104 the injector being placed on a side position of the cylinder
• CPC Class Codes: F02D 13/0211 the change of valve timing is caused by the change in valve lift, i.e. both valve lift and timing are functionally related
• CPC Class Codes: F02D 13/0219 by shifting the phase, i.e. the opening periods of the valves are constant
• CPC Class Codes: F02D 13/06 Cutting-out cylinders
• CPC Class Codes: F02D 17/02 Cutting-out cutting-out engines in multiple engine arrangements F02D25/04
• CPC Class Codes: F02D 2041/001 for engines with variable valve actuation
• CPC Class Codes: F02D 41/008 Controlling each cylinder individually
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02D 41/3035 a mode being the premixed charge compression-ignition mode
• CPC Class Codes: F02D 41/3076 with special conditions for selecting a mode of combustion, e.g. for starting, for diagnosing
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A method to operate a multi-cylinder direct-injection engine in one of a controlled auto-ignition and a spark-ignition combustion mode is described. Engine operation and an operator torque request are monitored. Fuel delivery to a portion of the cylinders is selectively deactivated and torque output from non-deactivated cylinders is selectively increased to achieve the operator torque request when the monitored engine operation is above a predetermined threshold. An engine operating point at which an engine load demand exceeds an operating capability of the engine in a stoichiometric HCCI mode is identified. The engine is selectively operated in an unthrottled spark-ignition mode with at least one cylinder unfueled and torque output from the remaining cylinders is selectively increased.

Claims

1. Method to operate a multi-cylinder direct-injection engine, comprising:

adapting the engine to selectively operate in one of a controlled auto-ignition combustion mode and a spark-ignition combustion mode;

monitoring engine operation and an operator torque request; and

,

selectively deactivating fuel delivery to a portion of the cylinders and selectively increasing torque output from non-deactivated cylinders to achieve the operator torque request when the monitored engine operation is above a predetermined first threshold.

2. The method of claim 1, wherein the monitored engine operation comprises engine speed, and the predetermined first threshold is based upon the operator torque request.

3. The method of claim 1, further comprising:

adapting the engine to be selectively operative in one of a low-lift and a high-lift engine valve operation; and

,

controlling the engine to the high-lift engine valve operation concurrent with the selective deactivation of fuel delivery to the portion of the cylinders.

4. The method of claim 3, further comprising:

adapting the engine to be selectively operative at an air/fuel ratio that is one of lean of stoichiometry and substantially stoichiometric; and

,

controlling the engine to the substantially stoichiometric air/fuel ratio concurrent with the selective deactivation of fuel delivery to a portion of the cylinders.

5. The method of claim 1, further comprising:

adapting the engine to be selectively operative at an air/fuel ratio that is one of lean of stoichiometry and substantially stoichiometric; and

,

controlling the engine to the substantially stoichiometric air/fuel ratio concurrent with the selective deactivation of fuel delivery to a portion of the cylinders.

6. The method of claim 1, further comprising:

controlling throttle opening to a wide-open position concurrent with the selective deactivation of fuel delivery to a portion of the cylinders.

7. The method of claim 1, further comprising:

controlling spark timing and dwell of the ignition based upon the engine operation concurrent with the selective deactivation of fuel delivery to a portion of the cylinders.

8. The method of claim 1, further comprising:

selectively enabling fuel delivery to all of the cylinders when the operator torque request exceeds a second predetermined threshold.

9. Method for transitioning engine operation between a controlled auto-ignition combustion mode and a spark-ignition combustion mode, comprising:

adapting the engine to be selectively operative in one of a low-lift and a high-lift engine valve operation;

monitoring engine speed and engine load;

determining the engine speed is above a predetermined threshold;

selectively deactivating fuel delivery to a portion of the cylinders and selectively increasing torque output from non-deactivated cylinders to achieve the operator torque request and operating the engine at the high-lift engine valve operation when the engine load is within a predetermined range.

10. The method of claim 9, wherein the predetermined range for the engine load is based upon the engine speed.

11. The method of claim 10, further comprising:

adapting the engine to be selectively operative at an air/fuel ratio that is one of lean of stoichiometry and substantially stoichiometric; and

,

controlling the engine to the substantially stoichiometric air/fuel ratio concurrent with the selective deactivation of fuel delivery to a portion of the cylinders.

12. The method of claim 9, further comprising:

controlling throttle opening to a wide-open position concurrent with the selective deactivation of fuel delivery to a portion of the cylinders.

13. The method of claim 12, further comprising:

controlling spark timing and dwell of the ignition based upon the engine operation concurrent with the selective deactivation of fuel delivery to a portion of the cylinders.

14. The method of claim 9, further comprising:

controlling spark timing and dwell of the ignition based upon the engine operation concurrent with the selective deactivation of fuel delivery to a portion of the cylinders.

15. The method of claim 9, further comprising:

selectively enabling fuel delivery to all of the cylinders when the engine load is outside the predetermined threshold.

16. The method of claim 9, further comprising:

adapting the engine to be selectively operative in one of a low-lift, an intermediate-lift, and, a high-lift engine valve operation; and

,

selectively deactivating fuel delivery to a portion of the cylinders and operating the engine at one of the medium-lift and the high-lift engine valve operation and selectively increasing torque output from non-deactivated cylinders based upon an operator torque request.

17. Internal combustion engine, comprising:

a multi-cylinder direct-injection engine, adapted to operate at an air/fuel ratio that is one of lean of stoichiometry and substantially stoichiometric, comprising;

a variable valve lift control device selectively operative at one of low valve lift and high valve lift;

a control module, adapted to monitor inputs from a plurality of sensing devices and control a plurality of actuators based upon predetermined control schemes and adapted to cutoff fuel delivery to a portion of the cylinders during ongoing operation;

a control scheme, comprising a computer program encoded therein executable in the control module for controlling operation of the engine, the program comprising;

code to monitor engine operation and an operator torque request;

code to determine engine speed is above a predetermined threshold;

code to effect a transition between a spark-ignition combustion mode and a controlled auto-ignition combustion mode based upon the engine operation when the engine speed is above the predetermined threshold;

wherein the transition comprises;

code to control air/fuel ratio substantially to stoichiometry;

code to command variable valve lift to a high valve lift opening;

code to deactivate the portion of the cylinders by cutting off fuel delivery thereto during ongoing operation;

code to increase fuel delivery to the non-deactivated cylinders to meet the operator torque request;

code to control spark-ignition timing and dwell; and

,

code to control throttle to a wide-open position.