Pressure-charged internal combustion engine

• US 20060059910A1
• Filed: 09/22/2005
• Published: 03/23/2006
• Est. Priority Date: 09/22/2004
• Status: Abandoned Application

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Schorn, Norbert A., Kindl, Helmut M., Spaeder, Uwe R.
• Application Number:
  US11/232,607
• Publication Number:
  US 20060059910A1
• Time in Patent Office: Days
• US Class Current: 60/612
• CPC Class Codes: F01N 13/009 having two or more separate purifying devices arranged in series
• CPC Class Codes: F01N 13/0093 the purifying devices are of the same type
• CPC Class Codes: F01N 13/107 More than one exhaust manifold or exhaust collector
• CPC Class Codes: F01N 2240/36 an exhaust flap
• CPC Class Codes: F01N 2340/02 characterised by the distance of the apparatus to the engine, or the distance between two exhaust treating apparatuses
• CPC Class Codes: F01N 2340/06 characterised by the arrangement of the exhaust apparatus relative to the turbine of a turbocharger
• CPC Class Codes: F01N 3/101 Three-way catalysts
• CPC Class Codes: F01N 3/2006 Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating by electrically controlling the supply of combustible mixture or its constituents only F02D41/0235
• CPC Class Codes: F02B 29/0406 Layout of the intake air cooling or coolant circuit
• CPC Class Codes: F02B 37/013 with exhaust-driven pumps arranged in series
• CPC Class Codes: F02B 37/16 by bypassing charging air
• CPC Class Codes: F02B 37/162 by bypassing, e.g. partially, intake air from pump inlet to pump outlet
• 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 37/22 by varying cross-section of exhaust passages or air passages , e.g. by throttling turbine inlets or outlets or by varying effective number of guide conduits F02B37/24 takes precedence
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

The invention relates to a system and method for improving the emission characteristics of a pressure-charged internal combustion engine. The engine (1) has an intake line (2) and an exhaust-gas line (4) and at least two exhaust-gas turbochargers (6, 7) connected in series. Each turbocharger has a turbine (6a, 7a) in the exhaust-gas line (4) and a compressor (6b, 7b) in the intake line (2). The first exhaust-gas turbocharger (6) serves as high-pressure stage (6). The second exhaust-gas turbocharger (7) serves as low-pressure stage (7). Two exhaust-gas aftertreatment systems are located in between and after the turbines.

Claims

1. A pressure-charged internal combustion engine (1), comprising:

an intake line (2) for supplying fresh air;

an exhaust-gas line (4) for discharging the exhaust gas;

a first exhaust-gas turbocharger (6) having a first turbine (6a) arranged in the exhaust-gas line (4) and a first compressor (6b) arranged in the intake line (2), said first exhaust-gas turbocharger (6) serving as a high-pressure stage;

a second exhaust-gas turbocharger (7) having a second turbine (7a) arranged in the exhaust-gas line (4) downstream of said first turbine (6a) and a second compressor (7b) arranged in the intake line (2) upstream of said first compressor (6b), said second exhaust-gas turbocharger (7) serving as a low-pressure stage;

a first exhaust-gas aftertreatment system (8a) arranged downstream of said second turbine (7a); and

a second exhaust-gas aftertreatment system (8b) arranged between said two turbines (6a, 7a).

2. The engine of claim 1, further comprising:

a bypass line (9) connecting said exhaust-gas line (4) upstream of said first turbine (6a) to said exhaust-gas line (4) downstream of said second exhaust-gas aftertreatment system (8b); and

a valve (10) arranged in said bypass line (9).

3. The engine of claim 1 wherein said valve (10) is a butterfly valve.

4. The engine of claim 1 wherein said first and second exhaust-gas aftertreatment systems (8a, 8b) are of a similar type.

5. The engine (1) of claim 1 wherein said second exhaust-gas aftertreatment system (8b) is volumetrically smaller than said first exhaust-gas aftertreatment system (8a).

6. The engine (1) of claim 1 wherein said first and second exhaust-gas aftertreatment systems (8a, 8b) are oxidation catalytic converters.

7. The engine (1) of claim 1 wherein said first and second exhaust-gas aftertreatment systems (8a, 8b) are diesel particulate filters.

8. The engine (1) of claim 1 wherein said first and second exhaust-gas aftertreatment systems (8a, 8b) are 3-way catalytic converters.

9. The engine (1) of claim 1, further comprising:

a bypass line (11) connecting said intake line (2) upstream of said second compressor (6b) to said intake line (2) downstream of said second compressor (6b); and

a valve (12) arranged in said bypass line (11).

10. The engine (1) of claim 1, further comprising:

a charge-air cooler (5) arranged in said intake line (2) downstream of said first and second compressors (6b, 7b).

11. The engine (1) of claim 1 wherein said first turbine (6a) has a variable turbine geometry.

12. The engine (1) of claim 1 wherein said first compressor (6b) has a variable compressor geometry.

13. The engine (1) of claim 1 wherein said second turbine (7a) has a variable turbine geometry.

14. The engine (1) of claim 1, further comprising:

a bypass line (13) connecting said exhaust-gas line (4) upstream of said second turbine (7a) to said exhaust-gas line (4) downstream of said second turbine (7a); and

a valve (14) arranged in said bypass line (13).

15. A method for operating a pressure-charged internal combustion engine (1), comprising:

directing a predominant proportion of an exhaust gas-flow through a first turbine (6a) and a second exhaust-gas aftertreatment system (8b) during particular engine operating conditions wherein the engine (1) has an intake line (2) for supplying fresh air;

an exhaust-gas line (4) for discharging the exhaust gas;

a first exhaust-gas turbocharger (6) having said first turbine (6a) arranged in the exhaust-gas line (4) and a first compressor (6b) arranged in the intake line (2), said first exhaust-gas turbocharger (6) serving as a high-pressure stage;

a second exhaust-gas turbocharger (7) having a second turbine (7a) arranged in the exhaust-gas line (4) downstream of said first turbine (6a) and a second compressor (7b) arranged in the intake line (2) upstream of said first compressor (6b), said second exhaust-gas turbocharger (7) serving as a low-pressure stage;

a first exhaust-gas aftertreatment system (8a) arranged downstream of said second turbine (7a); and

said second exhaust-gas aftertreatment system (8b) arranged between said two turbines (6a, 7a). The method of claim 15 wherein said particular operating conditions include;

low exhaust mass flow and engine warm-up, said low exhaust mass flow occurring at low speed conditions and at low torque conditions.

17. The method of claim 15 wherein substantially all of said exhaust-gas flow is directed through said first turbine (6a) and said second exhaust-gas aftertreatment system (8b).

18. The method of claim 15, further comprising:

increasing a proportion of exhaust-gas flowing through a bypass line (9) when one of exhaust temperature, exhaust pressure, and engine torque increase wherein said bypass line (9) connects said exhaust-gas line (4) upstream of said first turbine (6a) to said exhaust-gas line (4) downstream of said second exhaust-gas aftertreatment system (8b) and said bypass line (9) has a valve (10) arranged therein.

19. The method of claim 15 wherein more than 80% of exhaust-gas is directed through said first bypass line (9) when a temperature in said first exhaust gas-aftertreatment system (8a) is greater than a light-off temperature of said first exhaust gas-aftertreatment system (8a).

20. The method of claim 15, further comprising:

adjusting a first valve (12) arranged in a first bypass line (11) based on a position of a second valve (10) arranged in a second bypass line wherein said first bypass line (11) connects said intake line (2) upstream of said first compressor (6b) to said intake line (2) downstream of said first compressor (6b), said second bypass line (9) connects said exhaust-gas line (4) upstream of said first turbine (6a) to said exhaust-gas line (4) downstream of said second exhaust-gas aftertreatment system (8b).

21. The method of claim 15, further comprising:

increasing exhaust-gas flow bypassing said second turbine (7a) when at least one of an engine torque and an engine speed increase wherein said exhaust-gas flow is conducted through a bypass line (13) connecting said exhaust-gas line (4) upstream of said second turbine (7a) to said exhaust-gas line (4) downstream of said second turbine (7a) said bypass line (13) having a valve (14) arranged therein.