Hybrid vehicle exhaust control strategy

• US 8,322,472 B2
• Filed: 05/04/2009
• Issued: 12/04/2012
• Est. Priority Date: 05/04/2009
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Gonze, Eugene V.
• Primary Examiner(s): Ilan, Ruth
• Assistant Examiner(s): SPISICH, GEORGE D
• Application Number:
  US12/434,986
• Publication Number:
  US 20100276223A1
• Time in Patent Office: 1,310 Days
• Field of Search: 180/65.21, 180/65.27, 180/65.275, 180/309, 123/142.5 R, 123/672, 123/676, 123/697, 701/102, 602/82, 602/86, 602/87, 603/00, 603/03
• US Class Current: 180/65.21
• CPC Class Codes: B01D 2251/208 Hydrocarbons
• CPC Class Codes: B01D 2258/012 Diesel engines and lean burn gasoline engines
• CPC Class Codes: B01D 53/9409 Nitrogen oxides
• CPC Class Codes: B01D 53/944 Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts three-way-catalysts [TWC] B01D53/9445
• CPC Class Codes: B01D 53/9477 with catalysts positioned on separate bricks, e.g. exhaust systems
• CPC Class Codes: B01D 53/9495 Controlling the catalytic process
• CPC Class Codes: B60L 2240/445 Temperature
• CPC Class Codes: B60W 10/06 including control of combustion engines
• 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: F01N 2590/11 for hybrid vehicles
• CPC Class Codes: F01N 3/2013 using electric or magnetic heating means
• CPC Class Codes: F01N 3/2066 Selective catalytic reduction [SCR]
• 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 41/405 with post injections
• 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

Abstract

A hybrid vehicle emission control method may include operating the hybrid vehicle in a first mode during which a combustion engine is off and an electric motor propels the hybrid vehicle. An electrically heated selective catalytic reduction catalyst (EHSCR) may be energized during the first mode. The vehicle may be operated in a second mode after the first mode during which the engine propels the hybrid vehicle.

Claims

1. A method comprising:

operating a hybrid vehicle in a first mode during which a combustion engine is off and an electric motor propels the hybrid vehicle;

energizing an electrically heated selective catalytic reduction catalyst (EHSCR) during the first mode;

operating the vehicle in a second mode after the first mode during which the engine propels the hybrid vehicle;

determining a first operating temperature of a passive selective catalytic reduction catalyst (PSCR) in communication with exhaust gas from the combustion engine and located downstream of the EHSCR; and

operating the vehicle in a catalyst combustion mode during the second mode when the first operating temperature is below a first predetermined limit, wherein the catalyst combustion mode includes injecting fuel into exhaust gas from the engine at a location before the PSCR.

2. The method of claim 1, further comprising determining a second operating temperature of the PSCR after operating the engine in the catalyst combustion mode and maintaining engine operation in the catalyst combustion mode when the second operating temperature is below the first predetermined limit.

3. The method of claim 2, wherein the first predetermined limit is at least 200 degrees Celsius.

4. The method of claim 2, further comprising deactivating the catalyst combustion mode when the second operating temperature is above the first predetermined limit.

5. The method of claim 1, further comprising determining a second operating temperature of an oxidation catalyst located upstream of the EHSCR before operating the vehicle in the second mode, wherein the engine operates in the catalyst combustion mode during the second mode when the second operating temperature is above a second predetermined limit.

6. The method of claim 5, wherein the second predetermined limit is at least 200 degrees Celsius.

7. The method of claim 5, wherein the fuel is injected at a location upstream of the oxidation catalyst.

8. The method of claim 1, wherein the EHSCR is maintained at an operating temperature of at least 200 degrees Celsius during vehicle operation in the first and second modes.

9. The method of claim 1, wherein the EHSCR is energized and operated at a temperature of at least 200 degrees Celsius before operation in the second mode.

10. A control module comprising:

a hybrid vehicle mode control module controlling vehicle operation in a first mode during which a combustion engine is off and an electric motor propels the vehicle and in a second mode during which the engine propels the vehicle;

an EHSCR control module in communication with the hybrid vehicle mode control module and an electrically heated selective catalytic reduction catalyst (EHSCR) and energizing the EHSCR during the first mode;

a catalyst temperature evaluation module determining an operating temperature of a passive selective catalytic reduction catalyst (PSCR); and

an engine emission control module in communication with the hybrid vehicle mode control module and the catalyst temperature evaluation module and operating the vehicle in a catalyst combustion mode during the second mode when the operating temperature is below a first predetermined limit, the catalyst combustion mode including injecting fuel into exhaust gas from the engine at a location before the PSCR.

11. The control module of claim 10, wherein the catalyst temperature evaluation module determines a second operating temperature of the PSCR after operating the engine in the catalyst combustion mode and the engine emission control module maintains engine operation in the catalyst combustion mode when the second operating temperature is below the first predetermined limit.

12. The control module of claim 11, wherein the first predetermined limit is at least 200 degrees Celsius.

13. The control module of claim 11, wherein the engine emission control module deactivates engine operation in the catalyst combustion mode when the second operating temperature is above the first predetermined limit.

14. The control module of claim 10, wherein the catalyst temperature evaluation module determines a second operating temperature of an oxidation catalyst located upstream of the EHSCR before operating the vehicle in the second mode, and wherein the engine emission control module operates the engine in the catalyst combustion mode during the second mode when the second operating temperature is above a second predetermined limit.

15. The control module of claim 14, wherein the second predetermined limit is at least 200 degrees Celsius.

16. The control module of claim 14, wherein the fuel is injected at a location upstream of the oxidation catalyst.

17. The control module of claim 10, wherein the EHSCR control module maintains the EHSCR at an operating temperature of at least 200 degrees Celsius during vehicle operation in the first and second modes.

18. The control module of claim 10, wherein the EHSCR control module energizes and operates the EHSCR at a temperature of at least 200 degrees Celsius before operation in the second mode.