SYSTEMS AND METHODS FOR A SPLIT EXHAUST ENGINE SYSTEM

• US 20180171898A1
• 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, Corona, Julian Barnaby, Madison, Daniel Paul, Boyer, Brad Alan
• Granted Patent: US 10,683,817 B2
• Time in Patent Office: Days
• CPC Class Codes: F01N 13/107 More than one exhaust manifold or exhaust collector
• CPC Class Codes: F01N 2240/02 a heat exchanger
• CPC Class Codes: F01N 2240/36 an exhaust flap
• CPC Class Codes: F01N 2410/00 By-passing, at least partially, exhaust from inlet to outlet of apparatus, to atmosphere or to other device
• CPC Class Codes: F01N 2430/10 by modifying inlet or exhaust valve timing
• CPC Class Codes: F01N 2560/08 the means being a pressure sensor
• CPC Class Codes: F01N 2590/11 for hybrid vehicles
• CPC Class Codes: F01N 2900/08 said parameters being related to the engine
• CPC Class Codes: F01N 3/023 using means for regenerating the filters, e.g. by burning trapped particles by electrically controlling the supply of combustible mixture or its constituents only F02D41/0235
• CPC Class Codes: F01N 3/101 Three-way catalysts
• CPC Class Codes: F01N 3/103 Oxidation catalysts for HC and CO only
• CPC Class Codes: F01N 3/2053 By-passing catalytic reactors, e.g. to prevent overheating
• CPC Class Codes: F02B 25/145 with intake and exhaust valves exclusively in the cylinder head
• CPC Class Codes: F02D 13/0215 changing the valve timing only
• 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 2041/001 for engines with variable valve actuation
• CPC Class Codes: F02D 41/005 according to engine operating conditions
• 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 41/144 Sensor in intake manifold
• CPC Class Codes: F02D 41/1448 the characteristics being an exhaust gas pressure
• CPC Class Codes: F02D 41/26 : using computer, e.g. microprocessor
• CPC Class Codes: F02M 26/04 : with a single turbocharger
• CPC Class Codes: F02M 26/14 : in relation to the exhaust system
• CPC Class Codes: F02M 26/20 : Feeding recirculated exhaust gases directly into the combustion chambers or into the intake runners
• CPC Class Codes: F02M 26/53 : using electric actuators, e.g. solenoids
• CPC Class Codes: Y02T 10/12 : Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 : Engine management systems

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, each of a first valve positioned in an exhaust gas recirculation (EGR) passage, the EGR passage coupled between the intake passage and the first exhaust manifold coupled to a first set of cylinder exhaust valves, and a second valve positioned in a flow passage coupled between the first exhaust manifold and the exhaust passage may be adjusted based on a measured pressure in the first exhaust manifold.

Claims

1. A method, comprising:

adjusting each of a first valve positioned in an exhaust gas recirculation (EGR) passage, the EGR passage coupled between an intake passage and a first exhaust manifold coupled to a first set of cylinder exhaust valves, and a second valve positioned in a flow passage coupled between the first exhaust manifold and an exhaust passage based on a measured pressure in the first exhaust manifold, the exhaust passage coupled to a second exhaust manifold coupled to a second set of cylinder exhaust valves.

2. The method of claim 1, further comprising, further adjusting the first valve and the second valve based on a desired pressure of the first exhaust manifold and further comprising determining the desired pressure based on an intake manifold pressure and a timing of cylinder intake valve and a timing of the first and second sets of cylinder exhaust valves.

3. The method of claim 2, wherein the adjusting each of the first valve and the second valve includes decreasing an amount of opening of the first valve in response to a request to reduce EGR and the determined desired pressure being higher that the measured pressured in the first exhaust manifold.

4. The method of claim 1, further comprising, further adjusting the first valve and the second valve based on one or more of engine speed, a desired amount of EGR, and boost pressure.

5. The method of claim 1, wherein adjusting each of the first valve and second valve includes decreasing an amount of opening of the first valve to a first amount of opening in response to an increase in engine load over a threshold load while engine speed is below a threshold speed, where the first amount of opening increases the measured pressure in the first exhaust manifold to an intake manifold pressure, and further comprising maintaining the first valve at the first amount of opening until the intake manifold pressure reaches a desired intake manifold pressure based on the engine load.

6. The method of claim 1, wherein adjusting each of the first valve and second valve includes decreasing an amount of opening of the second valve in response to a request to increase EGR flow through the EGR passage when the first valve is in a fully open position, and wherein the amount of decreasing is based on a desired pressure in the first exhaust manifold based on the requested increase in EGR flow and the measured pressure in the first exhaust manifold.

7. The method of claim 1, wherein adjusting each of the first valve and second valve includes fully opening the second valve and adjusting an amount of opening of the first valve to increase the measured pressure in the first exhaust manifold above an exhaust pressure of the exhaust passage in response to an intake throttle being at least partially closed during boosted engine operation.

8. The method of claim 1, further comprising estimating an amount of blowthrough air flow from cylinder intake valves to the first exhaust manifold via the first set of cylinder exhaust valves and an amount of exhaust gas flow from the first set of cylinder exhaust valves to the first exhaust manifold based on the measured pressure in the first exhaust manifold.

9. The method of claim 8, wherein adjusting each of the first valve and second valve includes adjusting a position of each of the first valve and the second valve to deliver a desired blowthrough air amount and a desired exhaust gas flow amount based on engine operating conditions.

10. The method of claim 1, further comprising adjusting a timing of the first set of cylinder exhaust valves based on the measured pressure in the first exhaust manifold.

11. The method of claim 10, further comprising further adjusting each of the first valve and the second valve in response to the adjusted timing of the first set of cylinder exhaust valves at the measured pressure in the first exhaust manifold.

12. The method of claim 1, wherein the measured pressure is determined based on an output of a pressures sensor positioned within the first exhaust manifold.

13. A method, comprising:

estimating a blowthrough amount from a cylinder intake valve to a first exhaust manifold via a first cylinder exhaust valve based on an output of a pressure sensor positioned in the first exhaust manifold, the first exhaust manifold coupled to an intake passage via an exhaust gas recirculation (EGR) passage, where a second cylinder exhaust valve of a same cylinder is coupled to a second exhaust manifold coupled to an exhaust passage; and

adjusting engine operation based on the estimated blowthrough amount.

14. The method of claim 13, wherein the estimating the blowthrough amount is further based on the output of the pressure sensor between a time of opening the cylinder intake valve of the same cylinder and a time of closing the first cylinder exhaust valve.

15. The method of claim 13, further comprising estimating an EGR flow amount based on the output of the pressure sensor and adjusting engine operation based on the estimated EGR flow, wherein the estimating the EGR flow amount if further based on the output of the pressure sensor between a time of opening the first cylinder exhaust valve and a time right before opening the cylinder intake valve of the same cylinder.

16. The method of claim 15, further comprising closing an EGR valve disposed in the EGR passage in response engine speed below a threshold speed and maintaining the EGR valve closed until the estimated EGR flow decreases to a desired EGR flow level based on the engine speed.

17. The method of claim 15, further comprising modulating a position of an EGR valve disposed in the EGR passage, wherein a rate of the modulating is based on a desired EGR flow based on engine operating conditions and the estimated EGR flow.

18. The method of claim 15, further comprising opening a valve disposed in a bypass passage coupled between the first exhaust manifold and the exhaust passage in response to engine power above a threshold power level and maintaining the valve open until the estimated EGR flow decreases to a desired EGR flow level based on the engine power.

19. The method of claim 13, wherein adjusting engine operation based on the estimated blowthrough amount includes adjusting one or more of a position of a first valve disposed in the EGR passage, a position of a second valve disposed in a bypass passage coupled between the first exhaust manifold and the exhaust passage, downstream of a turbine, a timing of the first cylinder exhaust valve, and a timing of a cylinder intake valve of the same cylinder.

20. A method, comprising:

in response to an increase in engine load over a threshold load while engine speed is below a threshold speed, decreasing an opening of a first valve positioned in a first passage, the first passage coupled between an intake passage and a first exhaust manifold exclusively coupled to a first set of cylinder exhaust valves, where the amount of decreasing is based on a pressure of the first exhaust manifold and an intake manifold pressure, while flowing a portion of exhaust gases to an exhaust passage via a second set of exhaust valves.