# US 2019/0093579 A1 · Systems and methods for a split exhaust engine system

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- Number: US 2019/0093579 A1
- Document ID: US20190093579A1
- Status: Published application
- Kind: A1
- Application number: 16/204,604
- Filed: 2018-11-29
- Published: 2019-03-28
- Earliest claimed: 2016-12-16
- Assignees: Ford Global Technologies, LLC
- Applicants: Ford Global Technologies, LLC
- Inventors: Joseph Norman Ulrey; Donald Lewis
- Web page: https://patentgrep.com/patent/US20190093579A1

## CPC

- F02D 41/029: {the exhaust gas treating apparatus being a particulate filter}
- F01N 3/021: by means of filters
- F01N 3/101: {Three-way catalysts}
- F01N 13/107: {More than one exhaust manifold or exhaust collector}
- F02B 29/08: Modifying distribution valve timing for charging purposes (F02B29/06 takes precedence)
- F02B 37/00: Engines characterised by provision of pumps driven at least for part of the time by exhaust
- F02D 13/0234: {changing the valve timing only}
- 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}
- F02D 13/0261: {Controlling the valve overlap}
- F02D 13/06: Cutting-out cylinders
- F02D 41/0007: {for control of turbo-charged or super-charged engines (control of the pumps per se F02B37/12)}
- F02D 41/005: {according to engine operating conditions}
- F02D 41/025: {by changing the composition of the exhaust gas, e.g. for exothermic reaction on exhaust gas treating apparatus}
- F02D 41/1454: {the characteristics being an oxygen content or concentration or the air-fuel ratio}
- F02D 41/1475: {Regulating the air fuel ratio at a value other than stoichiometry}
- F02M 35/10222: {Exhaust gas recirculation [EGR]; Positive crankcase ventilation [PCV]; Additional air admission, lubricant or fuel vapour admission}
- F02M 35/104: Intake manifolds
- F02D 13/0246: {changing valve lift or valve lift and timing}
- Y02T 10/12: Improving ICE efficiencies
- F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W)
- F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16)
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)
- F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## 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

### Claim 1

An engine operating method, comprising:
flowing air from an intake manifold through a plurality of engine cylinders, via a first set of cylinder exhaust valves exclusively coupled to a scavenge exhaust manifold, 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, the exhaust passage coupled to a blowdown exhaust manifold and the bypass passage coupled between the scavenge exhaust manifold and the exhaust passage, between the first and second emission control devices; and
flowing exhaust gas from a second set of cylinder exhaust valves exclusively coupled to the blowdown manifold to the first emission control device, via the exhaust passage, while flowing the air to the junction.

### Claim 2 (depends on 1)

The method of claim 1, wherein the exhaust passage includes a turbocharger turbine positioned upstream of the first emission control device.

### Claim 3 (depends on 1)

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.

### Claim 4 (depends on 1)

The method of claim 1, wherein flowing air from the intake manifold to the junction includes increasing an amount of opening of a first valve disposed in the bypass passage.

### Claim 5 (depends on 4)

The method of claim 4, where the condition is a flow rate into the engine exceeding a threshold.

### Claim 6 (depends on 4)

The method of claim 4, 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.

### Claim 7 (depends on 4)

The method of claim 4, wherein flowing air from the intake manifold to the junction further includes decreasing an amount of opening of a second valve disposed in an exhaust gas recirculation passage, the exhaust gas recirculation passage coupled between and to each of the scavenge exhaust manifold and an intake passage, the intake passage coupled to the intake manifold.

### Claim 8 (depends on 1)

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

### Claim 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; and
while flowing the exhaust gas, increasing an amount of overlap between a first set of intake valves and a set of second exhaust valves and increasing an amount of opening of a valve disposed in a bypass passage 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, the bypass coupled between and to each of the second exhaust manifold and the exhaust passage, between the first catalyst and the second catalyst.

### Claim 10 (depends on 9)

The method of claim 9, further comprising providing a stoichiometric gas mixture in between the first catalyst and the second catalyst and wherein the exhaust passage includes a turbocharger turbine disposed upstream of the first catalyst.

### Claim 11 (depends on 10)

The method of claim 10, further comprising, while flowing the exhaust gas, increasing the amount of overlap and increasing the amount of opening of the valve, decreasing an amount of opening of an exhaust gas recirculation valve disposed in a recirculation passage coupled between the second exhaust manifold and an intake passage of an engine, upstream of a turbocharger compressor.

### Claim 12

An engine operating method, comprising:
flowing blowdown gas without blowthrough air from a cylinder of an engine to a first and a second exhaust emissions devices via a blowdown exhaust valve and a blowdown manifold coupled to the blowdown exhaust valve during a cycle of the cylinder, the second exhaust emissions device downstream of the first exhaust emissions device; and
flowing an amount of blowthrough air from the cylinder to the second exhaust emissions device and not the first exhaust emissions device via a scavenge exhaust valve and scavenge manifold coupled to the scavenge exhaust valve during the cycle;
where the blowdown manifold is a first exhaust manifold in fluidic communication with a plurality of engine cylinders and a turbocharger turbine;
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; and
adjusting an amount of overlap between opening of the scavenge exhaust valve and opening of an intake valve of the cylinder to adjust the amount of blowthrough air in response to an air-fuel ratio of gases in the scavenge manifold.

### Claim 13 (depends on 12)

The method of claim 12, where the blowthrough air 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.

### Claim 14 (depends on 12)

The method of claim 12, 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.

### Claim 15 (depends on 14)

The method of claim 14, 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.

### Claim 16 (depends on 12)

The method of claim 12, further comprising flowing exhaust gas and blowthrough air to an intake manifold of an engine via the scavenge manifold while flowing blowthrough air from the cylinder to the second exhaust emissions device via the scavenge manifold.

### Claim 17 (depends on 12)

The method of claim 12, further comprising adjusting an amount of blowthrough air from the cylinder to the second exhaust emissions device via adjusting timing valve positioned along a passage between the scavenge manifold and the inlet of the second exhaust emissions device.

### Claim 18 (depends on 17)

The method of claim 17, further comprising adjusting the amount of blowthrough in response to an output of an oxygen sensor disposed in the scavenge manifold.

### Claim 19 (depends on 12)

The method of claim 12, further comprising opening a first valve in response to flow into an engine, the opening the first valve enabling the flowing blowthrough from the cylinder to the second exhaust emissions device.

### Claim 20 (depends on 19)

The method of claim 19, further comprising closing a second valve during opening the first valve, the second valve disposed in a passage between the scavenge manifold and an intake passage.