SYSTEMS AND METHODS FOR A SPLIT EXHAUST ENGINE SYSTEM

• US 20180171911A1
• Filed: 12/16/2016
• Published: 06/21/2018
• Est. Priority Date: 12/16/2016
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Ulrey, Joseph Norman, Lewis, Donald
• Granted Patent: US 10,161,332 B2
• Time in Patent Office: Days
• CPC Class Codes: F01N 13/107 More than one exhaust manifold or exhaust collector
• CPC Class Codes: F01N 3/021 by means of filters
• CPC Class Codes: F01N 3/101 Three-way catalysts
• CPC Class Codes: F02B 29/08 Modifying distribution valve timing for charging purposes F02B29/06 takes precedence
• CPC Class Codes: F02B 37/00 Engines characterised by provision of pumps driven at least for part of the time by exhaust
• CPC Class Codes: F02D 13/0234 changing the valve timing only
• CPC Class Codes: F02D 13/0246 changing valve lift or valve lift and timing
• CPC Class Codes: F02D 13/0257 Independent control of two or more intake or exhaust valves respectively, i.e. one of two intake valves remains closed or is opened partially while the other is fully opened
• CPC Class Codes: F02D 13/0261 Controlling the valve overlap
• CPC Class Codes: F02D 13/06 Cutting-out cylinders
• 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 41/005 according to engine operating conditions
• CPC Class Codes: F02D 41/025 by changing the composition of the exhaust gas, e.g. for exothermic reaction on exhaust gas treating apparatus
• CPC Class Codes: F02D 41/029 the exhaust gas treating apparatus being a particulate filter
• 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: F02M 35/10222 Exhaust gas recirculation [EGR]; Positive crankcase ventilation [PCV]; Additional air admission, lubricant or fuel vapour admission
• CPC Class Codes: F02M 35/104 Intake manifolds
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, an air-fuel control method for the engine system may include flowing air from the intake manifold through a plurality of engine cylinders to a junction of the exhaust passage and a bypass passage in response to a condition, the junction positioned along the exhaust passage between first and second emission control devices. The method may further include flowing exhaust gas to the first emission control device while flowing the air to the junction.

Claims

1. An engine operating method, comprising:

flowing air from an intake manifold through a plurality of engine cylinders to a junction of an exhaust passage and a bypass passage in response to a condition, the junction positioned along the exhaust passage between first and second emission control devices; and

flowing exhaust gas to the first emission control device while flowing the air to the junction.

2. The method of claim 1, where the exhaust passage is coupled to a blowdown exhaust manifold and the bypass passage is coupled between a scavenge exhaust manifold and the exhaust passage, between the first and second emission control devices.

3. The method of claim 2, where the blowdown exhaust manifold is coupled to a turbocharger and where the exhaust passage is coupled to the turbocharger.

4. The method of claim 3, where the exhaust gas is provided via the plurality of engine cylinders via a plurality of blowdown exhaust valves, the plurality of blowdown exhaust valves in fluidic communication with the blowdown exhaust manifold.

5. The method of claim 1, where the exhaust gas is a rich exhaust gas mixture that does not include air that has not participated in combustion in the plurality of engine cylinders, and where the air does not participate in combustion within the plurality of engine cylinders.

6. The method of claim 1, where the condition is a flow rate into the engine exceeding a threshold.

7. The method of claim 1, where the condition is a pressure drop across the second emission control device greater than a threshold, and where the first emission control device is a three-way catalyst and the second emission control device is a particulate filter.

8. The method of claim 1, further comprising providing a stoichiometric gas mixture at the junction.

9. An engine operating method, comprising:

flowing exhaust from a first exhaust manifold to a first catalyst and a second catalyst, the first exhaust manifold receiving exhaust gas exclusively via a first set of exhaust valves, the second catalyst arranged downstream of the first catalyst in an exhaust passage;

during a first mode while flowing the exhaust gas, increasing an amount of overlap between a first set of intake valves and a set of second exhaust valves to flow intake blowthrough air to the second catalyst without flowing intake blowthrough air to the first catalyst via a second exhaust manifold receiving gas exclusively via the set of second exhaust valves; and

during a second mode while flowing the exhaust gas, adjusting the amount of overlap to vary exhaust gas recirculation to an intake manifold of an engine.

10. The method of claim 9, further comprising providing a stoichiometric gas mixture in between the first catalyst and the second catalyst.

11. An engine operating method, comprising:

flowing blowdown gas without blowthrough from a cylinder of an engine to a first and a second exhaust emissions devices via a blowdown manifold during a cycle of the cylinder, the second exhaust emissions device downstream of the first exhaust emissions device; and

flowing blowthrough from the cylinder to the second exhaust emissions device and not the first exhaust emissions device via a scavenge manifold during the cycle.

12. The method of claim 11, where the blowthrough is air passing through the cylinder without participating in a combustion event and where the blowdown gas is blowdown exhaust gas that participated in the combustion event.

13. The method of claim 11, where the blowdown manifold is a first exhaust manifold in fluidic communication with a plurality of engine cylinders and a turbocharger turbine.

14. The method of claim 13, where the scavenge manifold is a second exhaust manifold in direct fluidic communication with the plurality of engine cylinders and an inlet of the second exhaust emissions device.

15. The method of claim 14, where flowing blowthrough is in response to a request to regenerate the second exhaust emissions device and engine intake manifold pressure greater than a pressure at an inlet of the second exhaust emissions device.

16. The method of claim 15, further comprising opening a valve positioned along a passage between the scavenge manifold and the inlet of the second exhaust emissions device in response to the request to regenerate the second exhaust emissions device.

17. The method of claim 11, further comprising flowing exhaust gas and blowthrough to an intake manifold of an engine via the scavenge manifold while flowing blowthrough from the cylinder to the second exhaust emissions device via the scavenge manifold.

18. The method of claim 11, further comprising adjusting an amount of blowthrough from the cylinder to the second exhaust emissions device via adjusting at least one of scavenge valve timing and intake valve timing.

19. The method of claim 18, further comprising adjusting the amount of blowthrough in response to an output of an oxygen sensor.

20. The method of claim 11, further comprising opening a valve in response to flow into an engine, the opening the valve enabling the flowing blowthrough from the cylinder to the second exhaust emissions device.