IN-CYLINDER EGR FOR AIR FUEL RATIO CONTROL

• US 20180106204A1
• Filed: 01/19/2017
• Published: 04/19/2018
• Est. Priority Date: 01/19/2016
• Status: Active Grant

• Current Assignee: Eaton Intelligent Power Limited (Eaton Corporation PLC.)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: McCarthy, JR., James E., Nielsen, Douglas
• Granted Patent: US 10,801,430 B2
• Time in Patent Office: Days
• CPC Class Codes: F02D 13/0215 changing the valve timing only
• CPC Class Codes: F02D 13/06 Cutting-out cylinders
• CPC Class Codes: F02D 2041/001 for engines with variable valve actuation
• CPC Class Codes: F02D 2041/0012 with selective deactivation of cylinders
• CPC Class Codes: F02D 41/0002 Controlling intake air
• CPC Class Codes: F02D 41/0052 Feedback control of engine parameters, e.g. for control of air/fuel ratio or intake air amount
• CPC Class Codes: F02D 41/0082 per groups or banks F02D41/0087 takes precedence
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02D 41/123 the fuel injection being cut-off
• CPC Class Codes: F02D 41/1454 the characteristics being an oxygen content or concentration or the air-fuel ratio
• CPC Class Codes: F02D 41/1475 Regulating the air fuel ratio at a value other than stoichiometry
• CPC Class Codes: F02D 41/3005 Details not otherwise provided for
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

Air to fuel ratio management comprises sensing a power output request for the engine and determining a fuel-efficient air to fuel ratio. A current air to fuel ratio is sensed in one or both of an intake manifold and an exhaust manifold connected to the engine. An air to fuel ratio adjustment is determined based on the fuel-efficient air to fuel ratio and based on the current air to fuel ratio. An in-cylinder exhaust gas recirculation technique is selected. The in-cylinder exhaust gas recirculation technique adjusts an oxygen and particulate content of exhaust gas resulting from combustion. A number of cylinders of the multiple-cylinder engine are selected to implement the in-cylinder exhaust gas recirculation technique. The intake valves and the exhaust valves are controlled to adjust the oxygen and particulate content of the exhaust gas by applying a second compression stroke of the respective reciprocating pistons to the exhaust gas.

Claims

1. A system for air to fuel ratio (AFR) management in a multiple-cylinder engine, the engine comprising respective reciprocating pistons in the multiple cylinders, the respective reciprocating pistons connected to a crankshaft for rotation of the crankshaft, a computer-controllable fuel injection system configured to inject fuel in to the multiple cylinders, respective computer-controllable intake valves and exhaust valves for opening and closing the multiple cylinders, and a computer control network connected to the fuel injection system and the respective intake valves and respective exhaust valves, the network comprising a processor, a tangible memory device, and processor-executable control algorithms for implementing a method for AFR management, the method comprising:

sensing a power output request for the engine;

determining a fuel-efficient air to fuel ratio based on the sensed power output;

sensing a current air to fuel ratio in one or both of an intake manifold connected to the engine and an exhaust manifold connected to the engine;

determining an air to fuel ratio adjustment based on the determined fuel-efficient air to fuel ratio and based on the sensed current air to fuel ratio;

selecting an in-cylinder exhaust gas recirculation technique based on the determined air to fuel ratio adjustment, wherein the in-cylinder exhaust gas recirculation technique adjusts an oxygen and particulate content of exhaust gas resulting from combustion;

selecting a number of cylinders of the multiple-cylinder engine to implement the in-cylinder exhaust gas recirculation technique; and

controlling the intake valves and the exhaust valves for the selected number of cylinders to adjust the oxygen and particulate content of the exhaust gas by applying a second compression stroke of the respective reciprocating pistons of the selected number of cylinders to the exhaust gas.

2. The system of claim 1, further comprising adjusting fuel injection by the fuel injection system based on the selected in-cylinder exhaust gas recirculation technique.

3. The system of claim 2, wherein adjusting fuel injection to the multiple-cylinders comprises increasing fuel injection to combustion cylinders of the multiple-cylinders to increase a torque output of the combustion cylinders.

4. The system of claim 2, wherein adjusting fuel injection comprises terminating fuel injection to at least half of the cylinders of the multiple-cylinders.

5. The system of claim 2, wherein adjusting fuel injection comprises terminating fuel injection to all of the cylinders of the multiple-cylinders.

6. The system of claim 2, wherein adjusting fuel injection comprises increasing fuel injected in to the selected number of cylinders.

7. The system of claim 2, wherein adjusting fuel injection comprises decreasing fuel injected in to the selected number of cylinders.

8. The system of claim 2, wherein adjusting fuel injection comprises terminating fuel injected in to the selected number of cylinders.

9. The system of claim 1, wherein selecting the in-cylinder exhaust gas recirculation technique comprises selecting among a cylinder deactivation mode, a reverse-breathing mode, and a re-breathing mode.

10. The system of claim 9, wherein selecting the in-cylinder exhaust gas recirculation technique comprises selecting two in-cylinder exhaust gas recirculation techniques to implement simultaneously on different cylinders of the multiple cylinders.

11. The system of claim 9, wherein the cylinder deactivation mode comprises deactivating fuel injection, intake valve actuation and exhaust valve actuation for at least one stroke cycle of the reciprocating pistons, and wherein a stroke cycle comprises from two to sixteen strokes of the reciprocating pistons within their respective cylinders.

12. The system of claim 11, wherein the cylinder deactivation mode further comprises reactivating fuel injection by the fuel injection system to the selected number of cylinders after a respective piston stroke from bottom dead center to top dead center in the selected number of cylinders without opening either of the respective intake valves or the respective exhaust valves for the selected number of cylinders.

13. The system of claim 9, wherein the re-breathing mode comprises:

deactivating intake valve actuation for the selected number of cylinders, and adjusting timing of exhaust valve actuation to correspond with piston travel in the selected number of cylinders such that the exhaust valves for the selected number of cylinders open when respective reciprocating pistons travel from top dead center to bottom dead center in the selected number of cylinders so as to draw exhaust from an exhaust manifold in to the selected number of cylinders.

14. The system of claim 13, wherein the re-breathing mode comprises closing both of the respective intake valves and the respective exhaust valves for the selected number of cylinders while the respective reciprocating pistons travel in a compression stroke and through a power stroke, from bottom dead center to top dead center and back to bottom dead center, in the selected number of cylinders.

15. The system of claim 14, wherein the re-breathing mode further comprises opening the respective exhaust valves for the selected number of cylinders after the power stroke and as the respective reciprocating pistons travel from bottom dead center back to top dead center in the selected number of cylinders.

16. The system of claim 14, wherein the re-breathing mode comprises holding the respective exhaust valves open to expel compressed exhaust after the power stroke as the respective reciprocating pistons rise from bottom dead center back to top dead center and, without closing the respective exhaust valves, holding the respective exhaust valves open as the respective reciprocating pistons travel from top dead center back to bottom dead center in the selected number of cylinders.

17. The system of claim 14 further comprising reactivating fuel injection by the fuel injection system to the selected number of cylinders while both of the respective intake valves and the respective exhaust valves are closed during the compression stroke and the power stroke.

18. The system of claim 9, wherein the reverse-breathing mode comprises:

adjusting timing of respective exhaust valve actuation for the selected number of cylinders to correspond with piston travel in the selected number of cylinders such that the exhaust valves for the selected number of cylinders open when respective reciprocating pistons travel from top dead center to bottom dead center in the selected number of cylinders so as to draw exhaust from an exhaust manifold in to the selected number of cylinders; and

adjusting timing of respective intake valve actuation for the selected number of cylinders to correspond with piston travel in the selected number of cylinders such that the respective intake valves open when respective reciprocating pistons travel from bottom dead center to top dead center in the selected number of cylinders.

19. The system of claim 18, wherein the reverse-breathing mode comprises closing both of the respective intake valves and the respective exhaust valves for the selected number of cylinders while the respective reciprocating pistons travel in a compression stroke and through a power stroke, from bottom dead center to top dead center and back to bottom dead center, in the selected number of cylinders.

20. The system of claim 19, wherein the reverse-breathing mode further comprises opening the respective intake valves for the selected number of cylinders after the power stroke and as the respective reciprocating pistons travel from bottom dead center back to top dead center in the selected number of cylinders.

21. The system of claim 19, further comprising reactivating fuel injection by the fuel injection system to the selected number of cylinders while both of the respective intake valves and the respective exhaust valves are closed during the compression stroke and the power stroke.

22. The system of claim 18, wherein the reverse-breathing mode comprises a two-stroke cycle for pumping exhaust through the selected number of cylinders, and wherein the second compression stroke corresponds to when respective reciprocating pistons travel from bottom dead center to top dead center in the selected number of cylinders.

23. The system of claim 1, wherein the second compression stroke reduces the amount of available oxygen in the exhaust gas.

24. The system of claim 1, further comprising increasing the temperature of the exhaust gas to raise the temperature of a catalyst downstream from the engine.

25. The system of claim 1, further comprising an intake manifold port configured to direct intake gases within the intake manifold connected to the engine, and wherein the intake manifold port is configured to encourage homogenous mixing of gases in the intake manifold when the in-cylinder exhaust gas recirculation technique is implemented.

26. The system of claim 1, further comprising an intake manifold port configured to direct intake gases within the intake manifold connected to the engine, and wherein the intake manifold port is configured to concentrate heat in areas of the intake manifold when the in-cylinder exhaust gas recirculation technique is implemented.

27. The system of claim 1, further comprising an intake manifold port configured to direct intake gases within the intake manifold connected to the engine, and wherein the intake manifold port is configured to concentrate the presence of recirculated exhaust gas in areas of the intake manifold when the in-cylinder exhaust gas recirculation technique is implemented.

28. The system of claim 1, further comprising a first intake plenum and a second intake plenum, and a divider therebetween.

29. The system of claim 28 further comprising a controllable valve in the divider.

30. The system of claim 28, further comprising a second intake manifold port, wherein the first intake manifold port is affiliated with the first intake plenum and the first intake manifold port and the first intake plenum are configured to tailor fluid flow to the selected number of cylinders, and wherein the second intake manifold port is affiliated with the second intake plenum and the second intake manifold port and the second intake manifold plenum are configured to tailor fluid flow to remaining cylinders of the multiple cylinders.

31. The system of claim 1, further comprising an exhaust manifold port configured to direct exhaust gases within the exhaust manifold connected to the engine, and wherein the exhaust manifold port is configured to encourage homogenous mixing of gases in the exhaust manifold when the in-cylinder exhaust gas recirculation technique is implemented.

32. The system of claim 1, further comprising an exhaust manifold port configured to direct exhaust gases within the exhaust manifold connected to the engine, and wherein the exhaust manifold port is configured to concentrate heat in areas of the exhaust manifold when the in-cylinder exhaust gas recirculation technique is implemented.

33. The system of claim 1, further comprising an exhaust manifold port configured to direct intake gases within the exhaust manifold connected to the engine, and wherein the exhaust manifold port is configured to concentrate exhaust gas in areas of the exhaust manifold when the in-cylinder exhaust gas recirculation technique is implemented.

34. The system of claim 33, further comprising at least one valve in the exhaust manifold port to control a back-pressure in the exhaust manifold.

35. The system of claim 1, further comprising a first exhaust plenum and a second exhaust plenum, and a divider therebetween.

36. The system of claim 35 further comprising a controllable valve in the divider.

37. The system of claim 28, further comprising a second exhaust manifold port, wherein the first exhaust manifold port is affiliated with the first exhaust plenum and the first exhaust manifold port and the first exhaust plenum are configured to tailor fluid flow to the selected number of cylinders, and wherein the second exhaust manifold port is affiliated with the second exhaust plenum and the second exhaust manifold port and the second exhaust manifold plenum are configured to tailor fluid flow to remaining cylinders of the multiple cylinders.

38. The system of claim 1, wherein the method for AFR management further comprises scavenging exhaust gas from downstream of the exhaust manifold.

39. A system for temperature management in a multiple-cylinder engine, the engine comprising respective reciprocating pistons in the multiple cylinders, the respective reciprocating pistons connected to a crankshaft for rotation of the crankshaft, a computer-controllable fuel injection system configured to inject fuel in to the multiple cylinders, respective computer-controllable intake valves and exhaust valves for opening and closing the multiple cylinders, and a computer control network connected to the fuel injection system and the respective intake valves and respective exhaust valves, the network comprising a processor, a tangible memory device, and processor-executable control algorithms for implementing a method for temperature management, the method comprising:

sensing a power output request for the engine;

sensing a current air to fuel ratio in one or both of an intake manifold connected to the engine and an exhaust manifold connected to the engine;

sensing a low temperature condition in one or both of the intake manifold or the exhaust manifold;

determining a thermal management air to fuel ratio adjustment based on the sensed current air to fuel ratio and based on the low temperature condition;

selecting an in-cylinder exhaust gas recirculation technique based on the determined thermal management air to fuel ratio adjustment, wherein the in-cylinder exhaust gas recirculation technique adjusts an oxygen and particulate content of exhaust gas resulting from combustion to lower the air to fuel ratio of gases available for combustion;

selecting a number of cylinders of the multiple-cylinder engine to implement the in-cylinder exhaust gas recirculation technique;

controlling the intake valves and the exhaust valves for the selected number of cylinders to apply a second compression stroke of the respective reciprocating pistons of the selected number of cylinders to the exhaust gas; and

adjusting the temperature of the exhaust gas by recombusting the exhaust gas that has had a second compression stroke applied.