Control of an Exhaust Gas Aftertreatment Device in a Hybrid Vehicle

• US 20090025371A1
• Filed: 06/17/2008
• Published: 01/29/2009
• Est. Priority Date: 06/19/2007
• Status: Active Grant

• Current Assignee: Volvo Car Corporation (AB Volvo)
• Original Assignee: Volvo Car Corporation (AB Volvo)
• Inventors: Vollmer, Niklas, Johnsson, Anders Holger, Hermansson, Jonas
• Granted Patent: US 8,438,837 B2
• Time in Patent Office: Days
• US Class Current: 60/286
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60L 2240/445 Temperature
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/30 including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 2510/068 Engine exhaust temperature
• CPC Class Codes: B60W 2710/0605 Throttle position
• CPC Class Codes: B60W 2710/0616 Position of fuel or air injector
• CPC Class Codes: B60W 2710/0688 Engine temperature
• CPC Class Codes: B60W 2710/088 Temperature
• CPC Class Codes: F01N 3/20 specially adapted for catalytic conversion F01N3/22 takes precedence; Methods of operation or control of catalytic converters
• CPC Class Codes: F01N 3/2033 using a fuel burner or introducing fuel into exhaust duct
• CPC Class Codes: F01N 3/22 Control of additional air supply only, e.g. using by-passes or variable air pump drives
• CPC Class Codes: F02D 41/025 by changing the composition of the exhaust gas, e.g. for exothermic reaction on exhaust gas treating apparatus
• CPC Class Codes: F02D 41/123 the fuel injection being cut-off
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 Engine management systems
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles

Abstract

The present invention involves a method for maintaining temperature in an exhaust gas treatment device for an internal combustion engine in a hybrid vehicle. The engine has a crankshaft and at least one cylinder. The hybrid vehicle has a fuel storage device and a fuel supply device. An exhaust gas treatment device is located downstream of the cylinder. The method comprises, in an engine off mode, pumping air to the exhaust gas aftertreatment device controlling the fuel supply device so that fuel is allowed to the exhaust gas aftertreatment device. Air flow to the exhaust gas aftertreatment device can be controlled by a throttle in an inlet duct to the engine and/or the fuel supply device to control the combustion and air-fuel ratio in the exhaust gas treatment device.

Claims

1. A method for operating an internal combustion engine in a hybrid vehicle, the engine having a crankshaft, at least one cylinder and an exhaust gas aftertreatment device coupled to an exhaust of the engine, the hybrid vehicle having a fuel storage device and a fuel supply device, said method comprising:

pumping air to the exhaust gas aftertreatment device when the engine is off;

commanding the fuel supply device to provide a desired amount of fuel to provide combustion in the exhaust gas aftertreatment device.

2. The method of claim 1 wherein said hybrid vehicle has an additional power source and said pumping air is provided by causing said additional power source to rotate the engine, said engine and said additional power source are coupled via a transmission.

3. The method of claim 1 wherein said commanding the fuel supply device is controlled to provide a desired location of maximum temperature in the exhaust gas aftertreatment device.

4. The method of claim 1 wherein said engine has an inlet duct in which a throttle valve is disposed, the method further comprising:

controlling a position of said throttle valve to provide a desired location of maximum temperature in the exhaust gas aftertreatment device.

5. The method of claim 1 wherein said additional power source is controlled to provide a desired air flow into said engine to thereby provide a desired location of maximum temperature in the exhaust gas aftertreatment device.

6. The method of claim 1 wherein said combustion in the exhaust gas aftertreatment device provides a location of maximum temperature downstream of an upstream end of the exhaust gas aftertreatment device.

7. The method of claim 6 wherein said location of maximum temperature is at least 20% of the length away from an upstream end of the exhaust gas aftertreatment device.

8. The method of claim 6 wherein said location of maximum temperature is at least 50% of the length away from an upstream end of the exhaust gas aftertreatment device.

9. The method of claim 1 wherein said fuel storage device is a fuel vapor canister and said fuel supply device is a fuel purge gas valve.

10. The method of claim 1 wherein said fuel storage device is a fuel tank and said fuel supply device is a fuel injector.

11. The method of claim 1 wherein said pumping air to the exhaust gas aftertreatment device comprises supplying air downstream of the at least one cylinder.

12. The method of claim 1 wherein said commanding the fuel supply device comprises supplying fuel downstream of the at least one cylinder.

13. The method of claim 1 wherein the air-fuel mixture supplied to the exhaust gas aftertreatment device has a lambda value of at least 1.0.

14. The method of claim 1 wherein the air-fuel mixture supplied to the exhaust gas aftertreatment device has a lambda value between 1.25 and 2.0.

15. A method for operating a hybrid propulsion system, said propulsion system having an internal combustion engine and an additional power source, the engine having a crankshaft, at least one cylinder, an exhaust gas aftertreatment device coupled to an exhaust of the engine, a fuel tank for supplying fuel to the engine'"'"'s at least one fuel injector, said method comprising:

pumping air to the exhaust gas aftertreatment device when the engine is off by rotating the crankshaft by said additional power source;

commanding at least one fuel injector to inject fuel, said fuel transported through said at least one cylinder to the exhaust gas aftertreatment device.

16. The method of claim 15, further comprising:

controlling the quantity of injected fuel to control combustion in the exhaust gas aftertreatment device.

17. The method of claim 16 wherein said controlling comprises controlling a region of the exhaust gas aftertreatment device at which the temperature is at a maximum.

18. A hybrid vehicle propulsion system having an internal combustion engine and an additional power source, the internal combustion engine having a crankshaft and at least one cylinder, the hybrid vehicle propulsion system further having a fuel storage device, a fuel supply device coupled to the fuel storage device and disposed in the engine, an exhaust gas treatment device located downstream of the at least one cylinder, and a control unit electronically coupled to the fuel supply device and the additional power source, wherein said control unit causes the engine to be rotated by the additional power source while commanding the fuel supply device to provide fuel to the engine when the engine is off.

19. The system of claim 18, further comprising:

a throttle valve disposed in an intake duct of the engine, said throttle valve electronically coupled to the control unit wherein said control unit controls said throttle valve so as to provide a maximum temperature in the exhaust gas aftertreatment device at a desired location.

20. The system of claim 19 wherein the location of the maximum temperature of the exhaust gas aftertreatment device is downstream of an upstream end of the exhaust gas aftertreatment device.

21. The system of claim 19 wherein the location of the maximum temperature of the exhaust gas aftertreatment device is downstream of an upstream end of the exhaust gas aftertreatment device by at least 20% of the total length of said exhaust gas aftertreatment device.

22. The system of claim 19 wherein the location of the maximum temperature of the exhaust gas aftertreatment device is downstream of an upstream end of the exhaust gas aftertreatment device by at least 50% of the total length of said exhaust gas aftertreatment device.

23. The system of claim 18 wherein said fuel storage device is a fuel tank and said fuel supply device is a fuel injector.

24. The system of claim 18 wherein said fuel storage device is a fuel vapor container and said fuel supply device is a fuel purge gas valve.

25. The system of claim 18 wherein an air-fuel ratio supplied to the exhaust gas aftertreatment device is at least 1.0.

26. The system of claim 18 wherein an air-fuel ratio supplied to the exhaust gas aftertreatment device is between 1.25 and 2.0.

27. The system of claim 18 wherein said engine is off when substantially no combustion occurs within said at least one cylinder.

28. The system of claim 18 wherein said engine is a diesel engine, said fuel supply device is a fuel injector, and said fuel injector supplies fuel late in an expansion stroke when said engine is off.

29. The system of claim 23 wherein said fuel injector is disposed upstream of the cylinder.

30. The system of claim 23 wherein said fuel injector is disposed in the cylinder.