Torque control strategy for a diesel engine during lean-rich modulation using independent fuel injection maps

• US 6,990,951 B1
• Filed: 07/12/2004
• Issued: 01/31/2006
• Est. Priority Date: 07/12/2004
• Status: Active Grant

• Current Assignee: International Engine Intellectual Property Company, LLC (Volkswagen AG)
• Original Assignee: International Engine Intellectual Property Company, LLC (Volkswagen AG)
• Inventors: Liu, Zhengbai, Wei, Puning
• Primary Examiner(s): HUYNH, HAI H
• Application Number:
  US10/889,382
• Publication Number:
  US 20060005805A1
• Time in Patent Office: 568 Days
• Field of Search: 123/299, 123/300, 123/305, 123/443, 701103-105
• US Class Current: 123/299
• CPC Class Codes: F02D 2250/21 during a transition between engine operation modes or states
• CPC Class Codes: F02D 41/0007 for control of turbo-charged or super-charged engines control of the pumps per se F02B37/12
• CPC Class Codes: F02D 41/0077 Control of the EGR valve or actuator, e.g. duty cycle, closed loop control of position EGR valve position sensor F02M26/48
• CPC Class Codes: F02D 41/0275 the exhaust gas treating apparatus being a NOx trap or adsorbent
• CPC Class Codes: F02D 41/307 to avoid torque shocks

Abstract

A compression ignition engine (10) for a motor vehicle has a control system (20) for processing data, one or more combustion chambers (12), and fuel injectors (18) for injecting fuel into the chambers. The control system controls lean-rich modulation of fueling using independent maps. One set of maps is a set of lean fueling maps, and another set is a set of rich fueling maps. The strategy is represented by a flow diagram (30) and is useful in regenerating a NO_x adsorber catalyst (16) in the engine exhaust system (14) in a manner that controls torque so that the regeneration process is transparent to the operator of the vehicle.

Claims

1. A method of operating a compression ignition engine to accomplish lean-rich modulation of fueling, the method comprising:

processing certain data to modulate fueling between lean modulation and rich modulation;

during lean modulation, processing data representing a particular set of operating conditions to select a particular lean fueling map that comprises fueling data appropriate to the particular set of operating conditions for causing the engine to be fueled in a manner that causes the engine to run lean and develop a corresponding torque; and

during rich modulation, processing data representing substantially the same particular set of operating conditions to select a particular rich fueling map that comprises fueling data appropriate to that substantially same particular set of operating conditions for causing the engine to be fueled in a manner that causes the engine to run rich and develop substantially the same corresponding torque as during lean modulation.

2. A method as set forth in claim 1 wherein during lean modulation, the particular lean fueling map selected causes the engine to be fueled by a main fuel injection without post-injection.

3. A method as set forth in claim 1 wherein during lean modulation, the particular lean fueling map selected causes the engine to be fueled by a one or more pilot injections followed by a main fuel injection without post-injection.

4. A method as set forth in claim 1 wherein during rich modulation, the particular rich fueling map selected causes the engine to be fueled by a main fuel injection with post-injection.

5. A method as set forth in claim 1 wherein during rich modulation, the particular rich fueling map selected causes the engine to be fueled by a one or more pilot injections followed by a main fuel injection with post-injection.

6. A compression ignition engine comprising:

a control system for processing data including a set of lean fueling maps and a set of rich fueling maps;

one or more combustion chambers; and

a fueling system for injecting fuel into the one or more combustion chambers;

wherein the control system at times modulates fueling between lean modulation and rich modulation, and

for lean modulation, processes data representing a particular set of operating conditions to select a particular lean fueling map that comprises fueling data appropriate to the particular set of operating conditions for causing the engine to be fueled in a manner that causes the engine to run lean and develop a corresponding torque; and

for rich modulation, processes data representing substantially the same particular set of operating conditions to select a particular rich fueling map that comprises fueling data appropriate to that substantially same particular set of operating conditions for causing the engine to be fueled in a manner that causes the engine to run rich and develop substantially the same corresponding torque as during lean modulation.

7. An engine as set forth in claim 6 wherein for lean modulation, the control system selects a particular lean fueling map that causes the engine to be fueled by a main fuel injection without post-injection.

8. An engine as set forth in claim 6 wherein for lean modulation, the control system selects a particular lean fueling map that causes the engine to be fueled by one or more pilot injections followed by a main fuel injection without post-injection.

9. An engine as set forth in claim 6 wherein for rich modulation, the control system selects a particular rich fueling map that causes the engine to be fueled by a main fuel injection with post-injection.

10. An engine as set forth in claim 6 wherein for rich modulation, the control system selects a particular rich fueling map that causes the engine to be fueled by one or more pilot injections followed by a main fuel injection with post-injection.

11. A method of operating a compression ignition engine to accomplish lean-rich modulation of fueling for regeneration of a NO_x adsorber catalyst in an exhaust system of the engine, the method comprising:

processing certain data to modulate fueling between lean modulation and rich modulation;

during lean modulation, processing data representing a particular set of operating conditions to select a particular lean fueling map that comprises fueling data appropriate to the particular set of operating conditions for causing the engine to be fueled in a manner that causes the engine to run lean and develop a corresponding torque; and

during rich modulation, processing data representing substantially the same particular set of operating conditions to select a particular rich fueling map that comprises fueling data appropriate to that substantially same particular set of operating conditions for causing the engine to be fueled in a manner that causes the engine to run sufficiently rich to create sufficient carbon monoxide for regenerating the NO_x adsorber catalyst while developing substantially the same corresponding torque as during lean modulation.

12. A method as set forth in claim 11 wherein during lean modulation, the particular lean fueling map selected causes the engine to be fueled by a main fuel injection without post-injection.

13. A method as set forth in claim 11 wherein during lean modulation, the particular lean fueling map selected causes the engine to be fueled by a one or more pilot injections followed by a main fuel injection without post-injection.

14. A method as set forth in claim 11 wherein during rich modulation, the particular rich fueling map selected causes the engine to be fueled by a main fuel injection with post-injection.

15. A method as set forth in claim 11 wherein during rich modulation, the particular rich fueling map selected causes the engine to be fueled by a one or more pilot injections followed by a main fuel injection with post-injection.

16. A compression ignition engine comprising:

a control system for processing data including a set of lean fueling maps and a set of rich fueling maps;

one or more combustion chambers;

a fueling system for injecting fuel into the one or more combustion chambers; and

an exhaust system having a NO_x adsorber catalyst through which exhaust from the combustion chambers is constrained to pass;

wherein the control system at times modulates fueling between lean modulation and rich modulation for regenerating the NO_x adsorber catalyst, and

for lean modulation, processes data representing a particular set of operating conditions to select a particular lean fueling map that comprises fueling data appropriate to the particular set of operating conditions for causing the engine to be fueled in a manner that causes the engine to run lean and develop a corresponding torque; and

for rich modulation, processes data representing substantially the same particular set of operating conditions to select a particular rich fueling map that comprises fueling data appropriate to that substantially same particular set of operating conditions for causing the engine to be fueled in a manner that causes the engine to run sufficiently rich to create sufficient carbon monoxide for regenerating the NO_x adsorber catalyst while developing substantially the same corresponding torque as during lean modulation.

17. An engine as set forth in claim 16 wherein for lean modulation, the control system selects a particular lean fueling map that causes the engine to be fueled by a main fuel injection without post-injection.

18. An engine as set forth in claim 16 wherein for lean modulation, the control system selects a particular lean fueling map that causes the engine to be fueled by one or more pilot injections followed by a main fuel injection without post-injection.

19. An engine as set forth in claim 16 wherein for rich modulation, the control system selects a particular rich fueling map that causes the engine to be fueled by a main fuel injection with post-injection.

20. An engine as set forth in claim 16 wherein for rich modulation, the control system selects a particular rich fueling map that causes the engine to be fueled by one or more pilot injections followed by a main fuel injection with post-injection.