Systems and methods for controlling egr flow during transient conditions

Patent metadata

Field	Value
Publication number	US-2016237928-A1
Application number	US-201615138892-A
Country	US
Kind code	A1
Filing date	Apr 26, 2016
Priority date	Nov 4, 2013
Publication date	Aug 18, 2016
Grant date	—

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, 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 structured to interpret 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 in response to the EGR fraction deviation condition to adjust the amount of recirculated exhaust gas to the intake system toward the expected EGR fraction.

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 low pressure EGR loop that connects the exhaust passage downstream of the turbine to the intake passage upstream of the compressor, wherein the controller is configured to actuate a 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.

4 . 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.

5 . The system of claim 4 , wherein the controller is configured 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.

6 . The system of claim 2 , further comprising:
a compressor EGR passage connecting the EGR passage to the intake system upstream of the compressor; a high pressure EGR passage connecting the EGR passage to the exhaust passage; and a three-way control valve operable to selectively connect the EGR passage with each of the compressor EGR passage and the high pressure EGR passage, wherein the controller is configured to actuate the three-way control valve to adjust the amount of recirculated exhaust gas toward the expected EGR fraction by selectively providing at least one of a first portion of the EGR flow from the EGR passage to the intake passage through the compressor EGR passage, a second portion of the EGR flow from the EGR passage to the exhaust passage, and a portion of the exhaust flow from the exhaust passage to the intake system through the high pressure EGR passage and the EGR passage.

7 . The system of claim 1 , further comprising:
a high pressure EGR passage connecting the EGR passage to the exhaust passage and a one-way valve in the high pressure EGR passage operable to selectively permit a portion of the exhaust flow from the exhaust passage to the EGR passage; and a control valve in the EGR passage downstream of the connection of the high pressure EGR passage to the EGR passage, wherein the controller is configured to adjust the amount of recirculated exhaust gas toward the expected EGR fraction by actuating the one-way valve to selectively provide a portion of the exhaust flow from the exhaust passage to the intake system through the EGR passage and by actuating the control valve to selectively provide EGR flow and the portion of the exhaust flow in the EGR passage from the EGR passage to the intake system.

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 . 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:
a low pressure EGR passage connecting the EGR passage to the exhaust passage downstream of the turbine; and a control valve in the low 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 provide a portion of the EGR flow from the EGR passage to the exhaust passage.

11 . The system of claim 1 , wherein the at least one primary EGR cylinder is connected to the intake system with a first intake manifold and a first intake throttle, the plurality of non-primary EGR cylinders are connected to the intake system with a second intake manifold and a second intake throttle, and the controller is configured to adjust the amount of recirculated exhaust gas toward the expected EGR fraction by actuating the first intake throttle to regulate the charge flow to the at least one primary EGR cylinder to change the EGR flow from the at least one primary EGR cylinder.

12 . The system of claim 1 , wherein the at least one primary EGR cylinder is connected to a variable valve actuation mechanism and the controller is configured to adjust the amount of recirculated exhaust gas toward the expected EGR fraction by controlling the EGR flow from the at least one primary EGR cylinder with the variable valve actuating mechanism.

13 . The system of claim 1 , further comprising a fuel system connected by at least one injector to each of the at least one primary EGR cylinder and the plurality of non-primary EGR cylinders, wherein the controller is configured to adjust the amount of recirculated exhaust gas toward the expected EGR fraction by cutting fuelling to the at least one primary EGR cylinder to reduce the EGR flow from the at least one primary EGR cylinder.

14 . The system of claim 1 , wherein the at least one primary EGR cylinder includes at least two primary EGR cylinders, wherein a first exhaust port of each primary EGR cylinder is connected to the EGR passage and a second exhaust port of each primary EGR cylinder is connected to the exhaust passage.

15 . The system of claim 14 , wherein the exhaust

Assignees

• Cummins Inc

Inventors

• Lana Carlos Alcides
• Stroh David J
• Geckler Samuel C
• Dane Marten H
• Perfetto Anthony K
• 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

• F02M26/05

  High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor · CPC title

• F02D2021/083

  controlling exhaust gas recirculation electronically · 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

• F02M26/37

  with temporary storage of recirculated exhaust gas (internal exhaust gas recirculation F02M26/01) · CPC title