Systems and methods for control of turbine-generator in a split exhaust engine system

Patent metadata

Field	Value
Publication number	US-10364757-B2
Application number	US-201615145686-A
Country	US
Kind code	B2
Filing date	May 3, 2016
Priority date	May 3, 2016
Publication date	Jul 30, 2019
Grant date	Jul 30, 2019

Abstract

Methods and systems are provided to control exhaust energy delivered to a turbine of a turbine-generator coupled to a split exhaust engine system in order to limit turbine over-speed conditions and/or reduce generator vibration or reduce component over-heating conditions. In one example, a method may comprise in response to turbine speed greater than a threshold speed, selectively deactivating a first exhaust valve of one or more cylinders of a first and second cylinder group.

First claim

The invention claimed is:

1. A method for an engine, comprising:
delivering exhaust from a first exhaust valve of all cylinders of a first cylinder group to a first scroll of an exhaust turbine while delivering exhaust from a first exhaust valve of all cylinders of a second cylinder group to a second scroll of the exhaust turbine; and
delivering exhaust from a second exhaust valve of all cylinders of the first and second cylinder groups to an exhaust catalyst, while bypassing the exhaust turbine,
wherein, in response to a turbine speed of the exhaust turbine being greater than a threshold speed, selectively deactivating at least one first exhaust valve of at least one cylinder selected from the first and the second cylinder groups.

2. The method of claim 1 , wherein the exhaust turbine drives a generator.

3. The method of claim 1 , wherein the selectively deactivating at least one first exhaust valve of at least one cylinder selected from the first and the second cylinder groups further comprises selecting a sequence of selectively deactivating the at least one first exhaust valve of at least one cylinder selected from the first and the second cylinder groups and a duration of the selectively deactivating the at least one first exhaust valve of at least one cylinder selected from the first and the second cylinder groups based on the turbine speed.

4. The method of claim 3 , wherein the exhaust turbine drives a generator, and wherein the selectively deactivating at least one first exhaust valve of at least one cylinder selected from the first and the second cylinder groups for deactivation, the sequence of the selectively deactivating the at least one first exhaust valve of at least one cylinder selected from the first and the second cylinder groups, and the duration of the selectively deactivating at least one first exhaust valve of at least one cylinder selected from the first and the second cylinder groups is further based on generator power or current generator output relative to a threshold output.

5. The method of claim 3 , wherein the selectively deactivating at least one first exhaust valve of at least one cylinder selected from the first and the second cylinder groups for deactivation, the sequence of the selectively deactivating the at least one first exhaust valve of at least one cylinder selected from the first and the second cylinder groups, and the duration of the selectively deactivating the at least one first exhaust valve of at least one cylinder selected from the first and the second cylinder groups is further selected based on an exhaust system temperature relative to a threshold temperature.

6. The method of claim 1 , wherein the first exhaust valve of all cylinders of the first cylinder group is coupled to the first scroll of the exhaust turbine via a first exhaust manifold and the first exhaust valve of all cylinders of the second cylinder group is coupled to the second scroll of the exhaust turbine via a second, different exhaust manifold, and wherein the second exhaust valve of all cylinders of the first and second cylinder groups is coupled to the exhaust catalyst via a third exhaust manifold which bypasses the exhaust turbine.

7. The method of claim 1 , wherein the at least one first exhaust valve of at least one cylinder selected from the first cylinder group or the second cylinder group is selected based on a cylinder position along an engine block and firing order.

8. The method of claim 1 , wherein the selectively deactivating at least one first exhaust valve of at least one cylinder selected from the first and the second cylinder groups in response to the turbine speed greater than a threshold speed includes deactivating the first exhaust valve of one cylinder of the first and the second cylinder groups when a difference between the turbine speed and the threshold speed is larger than a first threshold value; and deactivating the first exhaust valve of each cylinder of the first and the second cylinder groups when the difference between the turbine speed and the threshold speed is larger than a second threshold value, wherein the second threshold value is larger than the first threshold value.

9. The method of claim 5 , wherein selectively deactivating at least one first exhaust valve of at least one cylinder selected from the first and the second cylinder groups for deactivation, the sequence of the selectively deactivating at least one first exhaust valve of at least one cylinder selected from the first and the second cylinder groups, and the duration of the selectively deactivating at least one first exhaust valve of at least one cylinder selected from the first and the second cylinder groups based on the exhaust system temperature further includes, in response to the exhaust system temperature being less than the threshold temperature, selectively deactivating the first exhaust valve of all cylinders of the first and second cylinder groups.

10. The method of claim 1 , wherein delivering exhaust from the first exhaust valve includes operating the first exhaust valve of each of the first cylinder and the second cylinder with a first exhaust valve opening timing advanced with respect to a second exhaust valve opening timing of the second exhaust valve of each of the first cylinder and the second cylinder.

11. The method of claim 1 , wherein delivering exhaust from the first exhaust valve further includes operating the first exhaust valve of each cylinder of the first cylinder group and the second cylinder group with a first exhaust valve closing timing advanced with respect to a second exhaust valve closing timing of the second exhaust valve of each cylinder of the first cylinder group and the second cylinder group.

12. A method for an engine, comprising:
flowing exhaust from a first exhaust valve of all cylinders of a first cylinder group to a first scroll of an exhaust turbine;
flowing exhaust from a first exhaust valve of all cylinders of a second cylinder group to a second scroll of the exhaust turbine, the exhaust turbine driving a generator;
flowing exhaust from a second exhaust valve of all cylinders of the first and second cylinder groups to an exhaust catalyst while bypassing the exhaust turbine; and
deactivating a first cylinder pattern of individual first exhaust valve mechanisms of the first and second cylinder groups responsive to a turbine speed higher than a threshold speed during a first operating condition; and
deactivating a second, different, cylinder pattern of individual first exhaust valve mechanisms of the first and second cylinder groups responsive to turbine speed higher than the threshold speed during a second operating condition different than and mutually exclusive from the first condition.

13. The method of claim 12 , wherein each of the first and second cylinder patterns is based on one or more of engine speed, engine load, engine temperature, and transmission gear selection.

14. The method of claim 12 , wherein the first cylinder pattern includes a first cylinder of the first cylinder group and a first cylinder of the second cylinder group and the second cylinder pattern includes a second cylinder of the first cylinder group and a second cylinder of the second cylinder group.

15. The method of claim 13 , wherein deactivating the first cylinder pattern includes:
selectively deactivating individual first exhaust valve mechanisms of one or more cylinders of only the first cylinder group when engine load is higher than a predetermined value, and selectively deactivating individual first exhaust valve mechanisms of one or more cylinders of both the first and the second cyl

Assignees

• Ford Global Tech Llc

Inventors

• Leone Thomas G
• Ulrey Joseph Norman

Classifications

• F02D41/021

  Introducing corrections for particular conditions exterior to the engine (conjoint control of vehicle sub-units for propelling the vehicle B60W30/18) · CPC title

• F02D17/02

  Cutting-out (cutting-out engines in multiple engine arrangements F02D25/04) · CPC title

• F02D13/0257

  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 title

• F01N13/107

  More than one exhaust manifold or exhaust collector · CPC title

• F01N13/10

  of exhaust manifolds {(with cooling jacket F01N3/046)} · CPC title