Systems and method for exhaust gas recirculation

Patent metadata

Field	Value
Publication number	US-2018347484-A1
Application number	US-201816043321-A
Country	US
Kind code	A1
Filing date	Jul 24, 2018
Priority date	Mar 28, 2016
Publication date	Dec 6, 2018
Grant date	—

Abstract

Various systems and methods are provided for exhaust gas recirculation. In one example, an exhaust gas recirculation (EGR) system includes an EGR passage coupling an engine exhaust system to an engine intake system, a first EGR cooler positioned in the EGR passage, the first EGR cooler configured to cool EGR with a first fluid, and a second EGR cooler positioned in the EGR passage downstream of the first EGR cooler, the second EGR cooler configured to cool EGR with a second fluid.

First claim

What is claimed is:

1 . A system, comprising:
an engine having a first subset of cylinders and a second subset of cylinders; a first exhaust manifold coupled to the first subset of cylinders and a second exhaust manifold coupled to the second subset of cylinders; a high-pressure turbocharger turbine coupled in an exhaust passage downstream of the engine; a low-pressure turbocharger turbine coupled in the exhaust passage downstream of the high-pressure turbocharger turbine; an exhaust gas recirculation (EGR) passage coupling the first exhaust manifold to an intake manifold of the engine; and a low-pressure exhaust passage coupling the exhaust passage downstream of the low-pressure turbine to the EGR passage via a venturi.

2 . The system of claim 1 , further comprising a valve positioned in the low-pressure exhaust passage and a controller configured to adjust a position of the valve based on one or more of EGR demand or a temperature of EGR in the EGR passage.

3 . The system of claim 1 , further comprising
a first EGR cooler positioned in the EGR passage, the first EGR cooler configured to cool EGR with a first fluid; and a second EGR cooler positioned in the EGR passage downstream of the first EGR cooler, the second EGR cooler configured to cool EGR with a second fluid.

4 . The system of claim 3 , wherein the first fluid comprises liquid coolant and the second fluid comprises exhaust gas from downstream of the low-pressure turbocharger turbine.

5 . The system of claim 3 , wherein the first fluid comprises exhaust gas from downstream of the low-pressure turbocharger turbine and the second fluid comprises liquid coolant.

6 . The system of claim 5 , wherein the EGR passage is configured to direct EGR from the engine exhaust system upstream of the low-pressure turbocharger turbine to the first EGR cooler, from the first EGR cooler to the second EGR cooler, and from the second EGR cooler to the engine intake system.

7 . The system of claim 5 , further comprising a cooling exhaust flow passage fluidically coupling the engine exhaust system downstream of the low-pressure turbocharger turbine to a cooling inlet of the first EGR cooler.

8 . The system of claim 7 , further comprising an exhaust return passage fluidically coupling a cooling outlet of the first EGR cooler to the engine exhaust system downstream of the low-pressure turbocharger turbine, wherein all exhaust gas that flows through the cooling exhaust flow passage also flows through the exhaust return passage.

9 . The system of claim 8 , wherein the first EGR cooler comprises an EGR inlet fluidically coupled to the EGR passage and an EGR outlet fluidically coupled to the second EGR cooler.

10 . The system of claim 9 , wherein the first EGR cooler is configured to flow EGR from the EGR inlet to the EGR outlet via one or more EGR flow passages, wherein the first EGR cooler is configured to flow exhaust gas from the cooling inlet to the cooling outlet via one or more coolant passages, and wherein the EGR and exhaust gas are maintained separately throughout an entirety of the first EGR cooler.

11 . The system of claim 9 , wherein EGR entering the first EGR cooler at the EGR inlet is at a higher pressure than exhaust gas entering the first EGR cooler at the cooling inlet.

12 . The system of claim 8 , wherein the cooling exhaust flow passage has an inlet coupled to an exhaust passage of the engine exhaust system downstream of the low-pressure turbocharger turbine, the exhaust return passage has an outlet coupled to the exhaust passage downstream of the inlet of the cooling exhaust flow passage, and the venturi is intermediate the inlet of the cooling exhaust flow passage and the outlet of the exhaust return passage.

13 . The system of claim 5 , further comprising a first coolant passage fluidically coupled to a cooling inlet of the second EGR cooler and a second coolant passage fluidically coupled to a cooling outlet of the second EGR cooler, and wherein the second EGR cooler comprises an EGR inlet fluidically coupled to the EGR passage.

14 . A system, comprising:
an engine having a first subset of cylinders and a second subset of cylinders; a first exhaust manifold coupled to the first subset of cylinders and a second exhaust manifold coupled to the second subset of cylinders; a high-pressure turbocharger coupled in an exhaust passage downstream of the engine, the high-pressure turbocharger comprising a high-pressure compressor and a high-pressure turbine, wherein the high-pressure turbine is coupled to the second exhaust manifold by the exhaust passage, and wherein all the exhaust produced by the second subset of cylinders is routed to the high-pressure turbine by the exhaust passage; a low-pressure turbocharger coupled in the exhaust passage downstream of the high-pressure turbocharger, the low-pressure turbocharger comprising a low-pressure compressor and a low-pressure turbine; an exhaust gas recirculation (EGR) passage coupling the first exhaust manifold to an intake manifold of the engine; and a low-pressure exhaust passage coupling the exhaust passage downstream of the low-pressure turbine to the EGR passage via a venturi.

15 . The system of claim 14 , further comprising a valve positioned in the low-pressure exhaust passage and a controller configured to adjust a position of the valve based on one or more of EGR demand or a temperature of EGR in the EGR passage.

16 . The system of claim 14 , further comprising
a first EGR cooler positioned in the EGR passage, the first EGR cooler configured to cool EGR with a first fluid; and a second EGR cooler positioned in the EGR passage downstream of the first EGR cooler, the second EGR cooler configured to cool EGR with a second fluid.

17 . The system of claim 16 , wherein the first fluid comprises liquid coolant and the second fluid comprises exhaust gas from downstream of the low-pressure turbine.

18 . The system of claim 16 , wherein the first fluid comprises exhaust gas from downstream of the low-pressure turbine and the second fluid comprises liquid coolant.

19 . The system of claim 18 , wherein the EGR passage is configured to direct EGR from upstream of the low-pressure turbine to the first EGR cooler, from the first EGR cooler to the second EGR cooler, and from the second EGR cooler to the intake manifold.

20 . A vehicle comprising:
an engine having a first subset of cylinders and a second subset of cylinders; an alternator configured to be driven by the engine to produce electrical power; one or more traction motors configured to receive the electrical power from the alternator to propel the vehicle; a first exhaust manifold coupled to the first subset of cylinders and a second exhaust manifold coupled to the second subset of cylinders; a high-pressure turbocharger coupled in an exhaust passage downstream of the engine, the high-pressure turbocharger comprising a high-pressure compressor and a high-pressure turbine, wherein the high-pressure turbine is coupled to the second exhaust manifold by the exhaust passage, and wherein all the exhaust produced by the second subset of cylinders is routed to the high-pressure turbine by the exhaust passage; a low-pressure turbocharger coupled in the exhaust passage downstream of the high-pressure turbocharger, the low-pressure turbocharger comprising a low-pressure compressor and a low-pressure turbine; an exhaust gas recirculation (EGR) passage coupling the first exhaust manifold to an intake manifold of the engine;

Assignees

• Gen Electric

Inventors

• Govind Shrinivas
• Jain Jayesh
• Sheth Pushkar Haresh

Classifications

• Y02T10/47

  Cross-Sectional Technologies · mapped topic

• F02D41/144

  Sensor in intake manifold · CPC title

• F02D41/0065

  Specific aspects of external EGR control (constructional details of EGR system F02M26/00) · CPC title

• F02M35/10222

  Exhaust gas recirculation [EGR]; Positive crankcase ventilation [PCV]; Additional air admission, lubricant or fuel vapour admission · CPC title

• F02M26/08

  for engines having two or more intake charge compressors or exhaust gas turbines, e.g. a turbocharger combined with an additional compressor · CPC title