Apparatus and method for controlling vehicle so as to purify exhaust emission from engine

• US 6,829,887 B2
• Filed: 12/26/2001
• Issued: 12/14/2004
• Est. Priority Date: 01/16/2001
• Status: Expired due to Term

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Kusada, Masaki, Suzuki, Takashi, Suzuki, Naoto, Yamazaki, Makoto
• Primary Examiner(s): Denion, Thomas
• Assistant Examiner(s): TRAN, DIEM T
• Application Number:
  US10/025,693
• Publication Number:
  US 20020092295A1
• Time in Patent Office: 1,084 Days
• Field of Search: 602/74, 602/84, 602/85, 602/99, 180/65.2, 180/65.4
• US Class Current: 60/284
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: F01N 13/009 having two or more separate purifying devices arranged in series
• CPC Class Codes: F01N 3/0814 combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts
• CPC Class Codes: F01N 3/0835 Hydrocarbons
• 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: F02D 41/0235 in relation with the state of the exhaust gas treating apparatus control of exhaust gas treating apparatus per se F01N
• CPC Class Codes: F02D 41/062 for starting F02D41/061 takes precedence
• CPC Class Codes: F02N 11/0818 Conditions for starting or stopping the engine or for deactivating the idle-start-stop mode
• 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
• CPC Class Codes: Y10S 903/903 having energy storing means, e.g. battery, capacitor

Abstract

Method and apparatus for controlling a vehicle so as to purify an exhaust emission from an internal combustion engine with an exhaust-emission purifying catalyst disposed in an exhaust system of the engine, and such that the engine is brought into a temporary engine-stop state while a predetermined vehicle condition is satisfied, wherein the engine is operated for heating the catalyst, when a temperature of the catalyst has been lowered below a predetermined lower limit threshold, even while the predetermined vehicle condition is still satisfied. The catalyst maintains an exhaust-emission purifying ability at a temperature above the lower limit threshold. When the catalyst temperature has been raised to a predetermined upper limit threshold, as a result of the engine operation, the engine is restored to the temporary engine-stop state if the predetermined condition is still satisfied. The present method and apparatus permit the catalyst temperature to be held at a level higher than the activation lower limit, while minimizing the reduction of an effect of the temporary engine stop in an economy-running-system vehicle or a hybrid vehicle.

Claims

1. A method of controlling a vehicle including an internal combustion engine such that the internal combustion is controlled so as to purify an exhaust emission from the internal combustion engine with an exhaust-emission purifying catalyst disposed in an exhaust system of the internal combustion engine, and such that the internal combustion engine is brought into a temporary engine-stop state while a predetermined condition of the vehicle is satisfied, said method comprising the steps of:

detecting a temperature of said exhaust-emission purifying catalyst;

operating the internal combustion engine when the detected temperature of the exhaust-emission purifying catalyst has been lowered below a predetermined lower limit threshold, even while said predetermined condition of the vehicle is still satisfied, the catalyst maintaining an exhaust-emission purifying ability at a temperature above said predetermined lower limit threshold; and

restoring the internal combustion engine to the temporary engine-stop state if the predetermined condition of the vehicle is still satisfied, when the temperature of the exhaust-emission purifying catalyst has been raised to a predetermined upper limit threshold higher than the lower limit threshold, the upper limit threshold providing a compromise between the frequency and time duration of the heating to occur as a result of the operation of the internal combustion engine while said predetermined condition of the vehicle is satisfied; and

wherein the operation of the internal combustion engine while said predetermined condition of the vehicle is satisfied is controlled so as to effectively heat said exhaust-emission purifying catalyst.

2. A method according to claim 1, wherein the operation of the internal combustion engine while said predetermined condition of the vehicle is satisfied is controlled so as to effectively heat said exhaust-emission purifying catalyst.

3. A method according to claim 2, wherein that the operation of the internal combustion engine while said predetermined condition of the vehicle is satisfied is effected with a delayed ignition timing of the engine, to promote the heating of the exhaust-emission purifying catalyst.

4. A method according to claim 2, wherein said vehicle is an economy-running-system vehicle or a hybrid vehicle.

5. A method according to claim 1, wherein said vehicle is an economy-running-system vehicle or a hybrid vehicle.

6. A method according to claim 1, wherein the operation of the internal combustion engine while said predetermined condition of the vehicle is satisfied is controlled so as to effectively heat said exhaust-emission purifying catalyst.

7. A method according to claim 6, wherein that the operation of the internal combustion engine while said predetermined condition of the vehicle is satisfied is effected with a delayed ignition timing of the engine, to promote the heating of the exhaust-emission purifying catalyst.

8. A method according to claim 6, wherein said vehicle is an economy-running-system vehicle or a hybrid vehicle.

9. A method according to claim 1, wherein said vehicle is an economy-running-system vehicle or a hybrid vehicle.

10. An apparatus for controlling a vehicle including an internal combustion engine such that the internal combustion engine is controlled so as to purify an exhaust emission from the internal combustion engine with an exhaust-emission purifying catalyst disposed in an exhaust system of the internal combustion engine, and such that the internal combustion engine is brought into a temporary engine-stop state while a predetermined condition of the vehicle is satisfied, said apparatus comprising a controller operable to operate the internal combustion engine when a temperature of the exhaust-emission purifying catalyst has been lowered below a predetermined lower limit threshold (Tcc1), even while said predetermined condition of the vehicle is still satisfied, the catalyst maintaining an exhaust-emission purifying ability at a temperature above said predetermined lower limit threshold;

and wherein said controller is operable to restore the internal combustion engine to said temporary engine-stop state if said predetermined condition of the vehicle is still satisfied, when the temperature of the exhaust-emission purifying catalyst has been raised to a predetermined upper limit threshold (Tcc2) higher than the lower limit threshold (Tcc1), the upper limit threshold providing a compromise between the frequency and time duration of the heating to occur as a result of the operation of the internal combustion engine while the predetermined condition of the vehicle is satisfied; and

wherein said controller is operable to control the operation of the internal combustion engine while said predetermined condition of the vehicle is satisfied, such that the operation of the internal combustion engine is effective to heat said exhaust-emission purifying catalyst.

11. An apparatus according to claim 10, wherein said controller is operable to control the operation of the internal combustion engine while said predetermined condition of the vehicle is satisfied, such that the operation of the internal combustion engine is effective to heat said exhaust-emission purifying catalyst.

12. An apparatus according to claim 11, wherein said controller is operable to control the operation of the internal combustion engine while said predetermined condition of the vehicle is satisfied, such that the internal combustion engine is operated with a delayed ignition timing, to promote the heating of the exhaust-emission purifying catalyst.

13. An apparatus according to claim 10, wherein said controller is operable to control the operation of the internal combustion engine while said predetermined condition of the vehicle is satisfied, such that the operation of the internal combustion engine is effective to heat said exhaust-emission purifying catalyst.

14. An apparatus according to claim 13, wherein said controller is operable to control the operation of the internal combustion engine while said predetermined condition of the vehicle is satisfied, such that the internal combustion engine is operated with a delayed timing, to promote the heating of the exhaust-emission purifying catalyst.

15. An economy-running-system vehicle provided with an apparatus according to claim 10.

16. An economy-running-system vehicle provided with an apparatus for controlling a vehicle including an internal combustion engine such that the internal combustion engine is controlled so as to purify an exhaust emission from the internal combustion engine with an exhaust-emission purifying catalyst disposed in an exhaust system of the internal combustion engine, and such that the internal combustion engine is brought into a temporary engine-stop state while a predetermined condition of the vehicle is satisfied, said apparatus comprising a controller operable to operate the internal combustion engine when a temperature of the exhaust-emission purifying catalyst has been lowered below a predetermined lower limit threshold (Tcc1), even while said predetermined condition of the vehicle is still satisfied, the catalyst maintaining an exhaust-emission purifying ability at a temperature above said predetermined lower limit threshold;

wherein said apparatus comprises the controller as recited in claim 10.

17. A hybrid vehicle provided with an apparatus according to claim 10.

18. A hybrid vehicle provided with an apparatus for controlling a vehicle including an internal combustion engine such that the internal combustion engine is controlled so as to purify an exhaust emission from the internal combustion engine with an exhaust-emission purifying catalyst disposed in an exhaust system of the internal combustion engine, and such that the internal combustion engine is brought into a temporary engine-stop state while a predetermined condition of the vehicle is satisfied, said apparatus comprising a controller operable to operate the internal combustion engine when a temperature of the exhaust-emission purifying catalyst has been lowered below a predetermined lower limit threshold (Tcc1), even while said predetermined condition of the vehicle is still satisfied, the catalyst maintaining an exhaust-emission purifying ability at a temperature above said predetermined lower limit threshold;

wherein said apparatus comprises the controller as recited in claim 10.