Constant EGR rate engine and method

• US 20070175215A1
• Filed: 02/02/2006
• Published: 08/02/2007
• Est. Priority Date: 02/02/2006
• Status: Active Grant

• Current Assignee: International Engine Intellectual Property Company, LLC (Volkswagen AG)
• Original Assignee: International Engine Intellectual Property Company, LLC (Volkswagen AG)
• Inventors: Rowells, Robert
• Granted Patent: US 7,788,923 B2
• Time in Patent Office: Days
• US Class Current: 60/605.200
• CPC Class Codes: F01N 13/009 having two or more separate purifying devices arranged in series
• CPC Class Codes: F02B 29/0418 the intake air cooler having a bypass or multiple flow paths within the heat exchanger to vary the effective heat transfer surface
• CPC Class Codes: F02B 37/04 Engines with exhaust drive and other drive of pumps, e.g. with exhaust-driven pump and mechanically-driven second pump
• CPC Class Codes: F02B 37/16 by bypassing charging air
• CPC Class Codes: F02B 37/18 by bypassing exhaust from the inlet to the outlet of turbine or to the atmosphere
• CPC Class Codes: F02B 37/24 by using pumps or turbines with adjustable guide vanes
• CPC Class Codes: F02M 26/08 for engines having two or more intake charge compressors or exhaust gas turbines, e.g. a turbocharger combined with an additional compressor
• CPC Class Codes: F02M 26/23 Layout, e.g. schematics
• CPC Class Codes: F02M 26/34 with compressors, turbines or the like in the recirculation passage
• CPC Class Codes: F02M 26/43 in which exhaust from only one cylinder or only a group of cylinders is directed to the intake of the engine
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

An internal combustion engine (100) includes a first exhaust manifold (120), and a second exhaust manifold (118) fluidly connected to the first exhaust manifold (120) through an exhaust valve (122). An exhaust gas recirculation (EGR) cooler (124) constantly fluidly connects the second exhaust manifold (118) with an intake manifold (112). A turbocharger (102) has a turbine (126) in fluid communication with the first exhaust manifold (120), and a compressor (132) in fluid communication with a supercharger (140). A charge air cooler (150) fluidly connects the supercharger (140) with the intake manifold (112).

Claims

1. An internal combustion engine, comprising:

a first exhaust manifold;

a second exhaust manifold fluidly connected to the first exhaust manifold through an exhaust valve;

an intake manifold in constant fluid communication with the second exhaust manifold;

an exhaust gas recirculation (EGR) cooler disposed between the second exhaust manifold and the intake manifold; and

a turbocharger having

a turbine in fluid communication with the first exhaust manifold, and

a compressor in fluid communication with a supercharger;

2. The internal combustion engine of claim 1, further comprising a supercharger bypass valve fluidly connecting the compressor with the intake manifold.

3. The internal combustion engine of claim 2, further comprising a check valve disposed between the compressor and the intake manifold.

4. The internal combustion engine of claim 1, further comprising a charge air cooler disposed between the supercharger and the intake manifold, and a charge air cooler bypass passage fluidly connecting the supercharger with the intake manifold.

5. The internal combustion engine of claim 4, further comprising a charge air cooler cut-off valve disposed between the supercharger and the charge air cooler.

6. The internal combustion engine of claim 1, further comprising a second turbine disposed between the EGR cooler and the second exhaust manifold, wherein the second turbine is arranged and constructed to provide a work output to the supercharger.

7. The internal combustion engine of claim 1, further comprising an after-treatment module disposed in fluid communication with the turbine.

8. The internal combustion engine of claim 7, wherein the after-treatment module is disposed between the turbine and the first exhaust manifold.

9. The internal combustion engine of claim 1, further comprising an EGR valve in fluid communication with the EGR cooler and disposed between the second exhaust manifold and the intake manifold.

10. A method comprising the steps of:

dividing an exhaust flow of an engine into a first portion and a second portion;

passing the first portion through a turbocharger;

recirculating the second portion to an intake system through an exhaust gas recirculation cooler;

compressing intake air in a compressor; and

supercharging intake air in a supercharger.

11. The method of claim 10, further comprising the step of bypassing a portion of intake air flow around the supercharger.

12. The method of claim 10, further comprising the step of passing the second portion through a second turbine before recirculating it to the exhaust gas recirculation cooler.

13. The method of claim 12, further comprising the step of bypassing an intake air flow around the charge air cooler.

14. The method of claim 10, further comprising the step of mixing the first portion and the second portion when the engine is cold.

15. The method of claim 10, wherein the first portion of exhaust gas is collected from a first set of cylinders, and wherein the second portion of exhaust gas is collected from a second set of cylinders.

16. The method of claim 15, further comprising the step of using a first exhaust valve timing for the first set of cylinders and using a second exhaust valve timing for the second set of cylinders.

17. The method of claim 15, further comprising the step of using an asymmetric fuel injection strategy for the first set of cylinders and the second set of cylinders.

18. The method of claim 10, wherein the engine is disposed in a vehicle and connected to a transmission having a clutch, further comprising the step of increasing a clutch engagement torque in the transmission.

19. A method for an internal combustion engine, comprising the steps of:

recirculating a substantially constant percentage of exhaust flow from an exhaust system of the engine into an intake system of the engine;

controlling a boost pressure of the engine with a supercharger having a bypass valve;

cooling an intake air flow using at least one of an inter-stage cooler disposed between the supercharger and a turbo-compressor and a charge air cooler disposed between the supercharger and the intake system;

controlling an exhaust pressure of the engine using at least one of a variable geometry turbine and a turbine waste-gate valve.

20. The method of claim 19, further comprising the step of controlling an air-to-fuel ratio of the engine with the bypass valve of the supercharger during a period of changing engine speed.