Systems and methods for controlling EGR flow during transient conditions

Patent metadata

Field	Value
Publication number	US-11028792-B2
Application number	US-201916241443-A
Country	US
Kind code	B2
Filing date	Jan 7, 2019
Priority date	Nov 4, 2013
Publication date	Jun 8, 2021
Grant date	Jun 8, 2021

Abstract

Systems, apparatus, and methods are disclosed that include a divided exhaust engine with at least one primary EGR cylinder and a plurality of non-primary EGR cylinders. The systems, apparatus and methods control the amount of recirculated exhaust gas in a charge flow in response to EGR fraction deviation conditions.

First claim

What is claimed is:

1. A system comprising:
an internal combustion engine having at least one primary exhaust gas recirculation (EGR) cylinder connected to provide an EGR flow to an EGR passage and a plurality of non-primary cylinders connected to provide an exhaust flow to an exhaust passage;
wherein the EGR passage is connected to an intake system to provide an EGR flow from the at least one primary EGR cylinder to the intake system, the EGR passage being one of flow isolated and flow isolatable from the exhaust passage;

the internal combustion engine having a low pressure EGR loop that connects the exhaust passage to the intake system;
wherein the intake system provides a charge flow to the at least one primary EGR cylinder and the plurality of non-primary cylinders, the charge flow including an intake air flow and an EGR fraction provided by an amount of recirculated exhaust gas from at least the at least one primary EGR cylinder; and

a controller operably connected to the internal combustion engine, the controller including a non-transitory computer readable medium with executable instructions:
during a transient operating condition of the internal combustion engine,
to determine an EGR fraction deviation condition in which the EGR fraction provided by the amount of recirculated exhaust gas in the charge flow deviates from an expected EGR fraction; and
to adjust the amount of recirculated exhaust gas to the intake system toward the expected EGR fraction in response to the EGR fraction deviation condition via actuation of an EGR control valve in the low pressure EGR loop to adjust the amount of recirculated exhaust gas toward the expected EGR fraction by selectively providing a portion of the exhaust flow from the exhaust passage to the intake system through the low pressure EGR loop and simultaneously providing a portion of EGR flow from the at least one primary EGR cylinder to the intake system.

2. The system of claim 1 , wherein:
the intake system includes a compressor in an intake passage that is connected to a turbine in the exhaust passage operable to drive the compressor with the exhaust flow from the plurality of non-primary EGR cylinders; and
the EGR passage is connected to the intake passage downstream of the compressor.

3. The system of claim 2 , wherein the EGR passage is flow isolated from the exhaust passage and further comprising a compressor EGR passage connecting the EGR passage to the intake system upstream of the compressor.

4. The system of claim 3 , wherein the controller further comprises executable instructions to actuate a control valve in the compressor EGR passage to selectively adjust the amount of recirculated exhaust gas toward the expected EGR fraction by selectively providing a portion of the EGR flow from the EGR passage to the intake system through the compressor EGR passage.

5. The system of claim 1 , wherein the intake system includes a compressor connected to a turbine in the exhaust passage and the turbine is operable to drive the compressor with the exhaust flow in the exhaust passage, and further comprising:
the low pressure EGR passage connecting the EGR passage to the exhaust passage downstream of the turbine.

6. The system of claim 1 , further comprising:
an EGR cooler in the low pressure EGR loop that is positioned upstream of the control valve.

7. The system of claim 1 , wherein the at least one primary EGR cylinder includes a single primary EGR cylinder that provides the EGR flow.

8. The system of claim 1 , further comprising a high pressure EGR passage connecting the EGR passage to the exhaust passage and a control valve in the high pressure EGR passage, wherein the controller is configured to adjust the amount of recirculated exhaust gas toward the expected EGR fraction by actuating the control valve to selectively provide one of a portion of the exhaust flow from the exhaust passage to the EGR passage and a portion of the EGR flow from the EGR passage to the exhaust passage.

9. The system of claim 8 , wherein the intake system includes a compressor that is connected to a turbine in the exhaust passage and the turbine is operable to drive the compressor with the exhaust flow in the exhaust passage, and the high pressure EGR passage is connected to the exhaust passage upstream of the turbine.

10. A method of controlling a charge flow to an internal combustion engine having at least one primary exhaust gas recirculation (EGR) cylinder connected to an EGR passage and a plurality of non-primary EGR cylinders connected to an exhaust passage, comprising:
supplying an exhaust flow from the non-primary EGR cylinders through the exhaust passage, wherein the exhaust passage is connected to a low pressure EGR loop that connects the exhaust passage to an intake system;
supplying an EGR flow from the at least one primary EGR cylinder through the EGR passage to the intake system, the charge flow including an EGR fraction corresponding to an amount of recirculated exhaust gas in the charge flow from at least the at least one primary EGR cylinder;
during a transient operating condition of the internal combustion engine,
determining, with a controller, an EGR fraction deviation condition in the charge flow to the internal combustion engine in response to a deviation of the EGR fraction from an expected EGR fraction via adjusting an EGR control valve in the low pressure EGR loop to adjust the amount of recirculated exhaust gas provided to the intake system; and
adjusting, with the controller, the amount of recirculated exhaust gas provided to the intake system to mitigate or reduce the deviation of the EGR fraction from the expected EGR fraction in response to determining the EGR fraction deviation condition.

11. The method of claim 10 , further comprising compressing the intake flow with a compressor in an intake passage of the intake system;
wherein the compressor is connected to a turbine in the exhaust passage that drives the compressor with the exhaust flow from the plurality of non-primary EGR cylinders.

12. The method of claim 11 , wherein:
the EGR passage is flow isolated from the exhaust passage and connected to the intake system downstream of the compressor; and
adjusting the recirculated amount of exhaust gas includes selectively providing a portion of the exhaust flow from the exhaust passage into the intake passage through the low pressure EGR loop connecting the exhaust passage to the intake passage downstream of the turbine and upstream of the compressor.

13. The method of claim 11 , wherein:
the EGR passage is flow isolated from the exhaust passage and connected to the intake system downstream of the compressor; and
adjusting the recirculated amount of exhaust gas includes selectively providing a portion of the EGR flow to the intake system through a compressor EGR passage that is connected to the intake system upstream of the compressor.

14. The method of claim 11 , wherein adjusting the recirculated amount of exhaust gas includes selectively providing a portion of the EGR flow from the EGR passage to the exhaust passage through a low pressure EGR passage connecting the EGR passage to the exhaust passage downstream of the turbine.

15. The method of claim 14 , wherein determining, with the controller, the EGR fraction deviation condition includes detecting a change in an engine operating condition during the transient operating condition of the internal combustion engine.

16. The method of claim 15 , wherein the engine operating condition includes at least one of a change in engine speed, a change in engine torque output, a

Assignees

• Cummins Inc

Inventors

• Lana Carlos Alcides
• Stroh David J
• Geckler Samuel C
• Dane Marten H
• Perfetto Anthony Kyle
• Kappaganthu Karthik
• Kothandaraman Govindarajan

Classifications

• F02B37/18 Primary

  by bypassing exhaust {from the inlet to the outlet of turbine or to the atmosphere} · CPC title

• Y02T10/12

  Improving ICE efficiencies · CPC title

• Y02T10/40

  Engine management systems · CPC title

• F02D13/02

  during engine operation · CPC title

• F02M26/13

  Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories · CPC title