Control apparatus for idling stop of internal combustion engine and vehicle with the apparatus mounted thereon

• US 6,453,865 B2
• Filed: 02/20/2001
• Issued: 09/24/2002
• Est. Priority Date: 03/06/2000
• Status: Expired due to Term

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Takahashi, Jun, Hirose, Kiyoo, Kitamura, Tooru, Ito, Yukikazu, Kato, Senji
• Primary Examiner(s): Mancene, Gene
• Assistant Examiner(s): Castro, Arnold
• Application Number:
  US09/785,226
• Publication Number:
  US 20010018903A1
• Time in Patent Office: 581 Days
• Field of Search: 123/179.4, 180/65.2, 180/65.3, 180/65.4, 477/5, 290/34, 290/38.E, 290/38.R, 290/40.A, 307/10.6
• US Class Current: 123/179.4
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60W 10/06 including control of combustion engines
• 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 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/0676 Engine temperature
• CPC Class Codes: B60W 2555/20 Ambient conditions, e.g. wind or rain
• CPC Class Codes: B60W 2710/081 Speed
• CPC Class Codes: F02D 2041/389 for injecting directly into the cylinder
• CPC Class Codes: F02D 41/042 for stopping the engine
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y10S 903/919 Stepped shift

Abstract

The technique of the present invention reduces or even omits potential shocks and vibrations arising due to the coupling action of a coupling mechanism at the time of starting an internal combustion engine, and ensures a quick restart of the internal combustion engine. In a vehicle with an idling stop control apparatus of the present invention mounted thereon, a control unit inputs an inverted phase current Eon, which is determined according to the energy absorbing state of a transmission belt, into an auxiliary machinery driving electric motor, so as to brake rotations of the auxiliary machinery driving electric motor. After the input of the inverted phase current Eon into the auxiliary machinery driving electric motor, the control unit couples an electromagnetic clutch to link a crankshaft of the internal combustion engine with the auxiliary machinery driving electric motor. The value of the inverted phase current Eon is varied according to the energy absorbing state of the transmission belt. The braking force of the auxiliary machinery driving electric motor is thus varied according to the energy absorbing state of the transmission belt.

Claims

1. An idling stop control apparatus mounted on a vehicle, wherein auxiliary machinery is driven by means of either one of an internal combustion engine and an electric motor, and an output shaft of said internal combustion engine and an output shaft of said electric motor are linked with each other via a coupling mechanism that is coupled to connect said internal combustion engine with said electric motor and is released to disconnect said internal combustion engine from said electric motor, said coupling mechanism being released and said auxiliary machinery being driven by means of said electric motor via a transmission belt while said internal combustion engine is at a stop, said idling stop control apparatus comprising:

a decision unit that determines whether a driving stop condition or a driving restart condition of said internal combustion engine is fulfilled;

a braking load specification unit that, when the driving restart condition of said internal combustion engine is fulfilled, specifies a braking load to be applied to said electric motor, in order to reduce electric motor velocity or number of revolutions of said electric motor according to a kinetic energy absorbing state of said transmission belt;

a drive stand-by unit that, when the driving restart condition of said internal combustion engine is fulfilled and said coupling mechanism is released, causes said output shaft of said internal combustion engine to be coupled with said output shaft of said electric motor via said coupling mechanism after application of the specified braking load to said electric motor; and

an internal combustion engine operation control unit that executes a series of processing to restart operation of said internal combustion engine after said internal combustion engine is coupled with said electric motor via said coupling mechanism.

2. An idling stop control apparatus in accordance with claim 1, wherein said vehicle further comprises a transmission belt elasticity measurement unit that measures elasticity of said transmission belt, and

said braking load specification unit determines the kinetic energy absorbing state of said transmission belt based on the observed elasticity of said transmission belt and increases the braking load with a decrease in observed elasticity of said transmission belt.

3. An idling stop control apparatus in accordance with claim 1, wherein said vehicle comprises a transmission belt temperature measurement unit that measures temperature of said transmission belt, and

said braking load specification unit determines the kinetic energy absorbing state of said transmission belt based on the observed temperature of said transmission belt and increases the braking load with a decrease in observed temperature of said transmission belt.

4. An idling stop control apparatus in accordance with claim 3, wherein said transmission belt temperature measurement unit comprises a cooling fluid temperature measurement unit that measures temperature of a cooling fluid passing through said internal combustion engine, and

said braking load specification unit determines the kinetic energy absorbing state of said transmission belt based on the observed temperature of the cooling fluid and increases the braking load with a decrease in observed temperature of the cooling fluid.

5. An idling stop control apparatus in accordance with claim 3, wherein said transmission belt temperature measurement unit comprises an engine velocity accumulation unit that accumulates engine velocity or number of revolutions of said internal combustion engine from a start to a stop of driving of said internal combustion engine, and

said braking load specification unit determines the kinetic energy absorbing state of said transmission belt based on the accumulated engine velocity and decreases the braking load with an increase in accumulated engine velocity.

6. An idling stop control apparatus in accordance with claim 3, wherein said transmission belt temperature measurement unit comprises an electric motor velocity accumulation unit that accumulates the electric motor velocity or the number of revolutions of said electric motor after a stop of driving of said internal combustion engine, and

said braking load specification unit determines the kinetic energy absorbing state of said transmission belt based on the accumulated electric motor velocity and decreases the braking load with an increase in accumulated electric motor velocity.

7. An idling stop control apparatus in accordance with claim 5, wherein said transmission belt temperature measurement unit further comprises an outside air temperature measurement unit that measures outside air temperature, and said braking load specification unit increases a rate of decrease of the braking load with an increase in observed outside air temperature.

8. A vehicle having an idling stop function to selectively stop and restart driving an internal combustion engine according to a driving state of said vehicle, wherein auxiliary machinery is driven by means of an electric motor while said internal combustion engine is at a stop and by means of said internal combustion engine while said internal combustion engine is in active state, said vehicle comprising:

a coupling mechanism that links an output shaft of said internal combustion engine with an output shaft of said electric motor, such as to be coupled to connect said internal combustion engine with said electric motor and to be released to disconnect said internal combustion engine from said electric motor;

a transmission belt that is laid through said output shaft of said internal combustion engine, an input shaft of said auxiliary machinery, and said output shaft of said electric motor;

a transmission belt state detection unit that detects a kinetic energy absorbing state of said transmission belt; and

an idling stop control unit that specifies a rate of decrease in electric motor velocity or number of revolutions of said electric motor based on the detected kinetic energy absorbing state of said transmission belt, and when a driving restart condition for restarting operation of said internal combustion engine is fulfilled, lowers the electric motor velocity by the specified rate of decrease, causes said output shaft of said internal combustion engine to be coupled with said output shaft of said electric motor via said coupling mechanism, and subsequently carries out a series of processing to restart driving said internal combustion engine.

9. A vehicle in accordance with claim 8, wherein said transmission belt state detection unit detects the kinetic energy absorbing state of said transmission belt based on elasticity of said transmission belt, and

said idling stop control unit enhances the rate of decrease in electric motor velocity with a decrease in elasticity of said transmission belt.

10. A vehicle in accordance with claim 8, wherein said transmission belt state detection unit detects the kinetic energy absorbing state of said transmission belt based on temperature of said transmission belt, and

said idling stop control unit enhances the rate of decrease in electric motor velocity with a decrease in temperature of said transmission belt.

11. A vehicle in accordance with claim 10, said vehicle further comprising:

a heat dissipation unit that is arranged on a windward side of said transmission belt to dissipate heat of a cooling fluid, which has passed through and cooled down said internal combustion engine; and

a cooling fluid temperature measurement unit that measures temperature of the cooling fluid,

wherein said transmission belt state detection unit calculates the temperature of said transmission belt from the observed temperature of the cooling fluid and detects the kinetic energy absorbing state of said transmission belt based on the calculated temperature of said transmission belt.

12. A vehicle in accordance with claim 10, said vehicle further comprising an engine velocity accumulation unit that accumulates engine velocity or number of revolutions of said internal combustion engine from a start to a stop of driving of said internal combustion engine,

wherein said transmission belt state detection unit calculates the temperature of said transmission belt from the accumulated engine velocity and detects the kinetic energy absorbing state of said transmission belt based on the calculated temperature of said transmission belt.

13. A vehicle in accordance with claim 10, said vehicle further comprising an electric motor velocity accumulation unit that accumulates electric motor velocity or number of revolutions of said electric motor after a stop of driving of said internal combustion engine,

wherein said transmission belt state detection unit calculates the temperature of said transmission belt from the accumulated electric motor velocity and detects the kinetic energy absorbing state of said transmission belt based on the calculated temperature of said transmission belt.

14. A vehicle in accordance with claim 12, said vehicle further comprising an outside air temperature measurement unit that measures outside air temperature,

wherein said transmission belt state detection unit calculates the temperature of said transmission belt from the observed outside air temperature in addition to at least one of the observed temperature of the cooling fluid, the accumulated engine velocity, and the accumulated electric motor velocity and detects the kinetic energy absorbing state of said transmission belt based on the calculated temperature of said transmission belt.

15. A vehicle in accordance with claim 8, wherein said idling stop control unit stops driving said internal combustion engine and releases said coupling mechanism when a driving stop condition of said internal combustion engine is fulfilled.

16. A vehicle having an idling stop function to selectively stop and restart driving an internal combustion engine according to a driving state of said vehicle, wherein auxiliary machinery is driven by means of an electric motor via a transmission belt while said internal combustion engine is at a stop and by means of said internal combustion engine while said internal combustion engine is in active state, said vehicle comprising:

a coupling mechanism that links an output shaft of said internal combustion engine with an output shaft of said electric motor, such as to be coupled to connect said internal combustion engine with said electric motor and to be released to disconnect said internal combustion engine from said electric motor;

a target braking velocity determination unit that determines a target braking velocity for braking said electric motor prior to a restart of driving of said internal combustion engine by taking into account temperature of said transmission belt; and

an idling stop control unit that, when a driving restart condition for restarting operation of said internal combustion engine is fulfilled, drives said electric motor at the target braking velocity, causes said output shaft of said internal combustion engine to be coupled with said output shaft of said electric motor via said coupling mechanism, and subsequently carries out a series of processing to restart driving said internal combustion engine.

17. A vehicle in accordance with claim 16, said vehicle further comprising:

a heat dissipation unit that is arranged on a windward side of said transmission belt to dissipate heat of a cooling fluid, which has passed through and cooled down said internal combustion engine; and

a cooling fluid temperature measurement unit that measures temperature of the cooling fluid,

wherein said target braking velocity determination unit takes into account the temperature of said transmission belt based on the observed temperature of the cooling fluid and lowers the target braking velocity with a decrease in observed temperature of the cooling fluid.

18. A vehicle in accordance with claim 17, said vehicle further comprising an engine velocity accumulation unit that accumulates engine velocity or number of revolutions of said internal combustion engine from a start to a stop of driving of said internal combustion engine,

wherein said target braking velocity determination unit takes into account the temperature of said transmission belt based on the accumulated engine velocity and raises the target braking velocity with an increase in accumulated engine velocity.

19. A vehicle in accordance with claim 17, said vehicle further comprising an electric motor velocity accumulation unit that accumulates electric motor velocity or number of revolutions of said electric motor after a stop of driving of said internal combustion engine,

wherein said target braking velocity determination unit takes into account the temperature of said transmission belt based on the accumulated electric motor velocity and raises the target braking velocity with an increase in accumulated electric motor velocity.

20. A vehicle in accordance with claim 18, said vehicle further comprising an outside air temperature measurement unit that measures outside air temperature,

wherein said target braking velocity determination unit varies a rate of increase in target braking velocity according to the observed outside air temperature.

21. A vehicle in accordance with claim 20, wherein said target braking velocity determination unit enhances the rate of increase in target braking velocity with an increase in observed outside air temperature.

22. A vehicle in accordance with claim 16, wherein said idling stop control unit stops driving said internal combustion engine and releases said coupling mechanism when a driving stop condition of said internal combustion engine is fulfilled.

23. A method of controlling idling stop in a vehicle that has an idling stop function to selectively stop and restart driving an internal combustion engine according to a driving state of said vehicle, wherein auxiliary machinery is driven by means of an electric motor while said internal combustion engine is at a stop, said method comprising the steps of:

detecting a kinetic energy absorbing state of a transmission belt that is laid through said internal combustion engine, said electric motor, and said auxiliary machinery;

determining whether or not a driving restart condition for restarting operation of said internal combustion engine is fulfilled;

when it is determined that the driving restart condition is fulfilled, specifying a rate of decrease in electric motor velocity or number of revolutions of said electric motor based on the detected kinetic energy absorbing state of said transmission belt; and

lowering the electric motor velocity by the specified rate of decrease and subsequently causing said output shaft of said internal combustion engine to be coupled with said output shaft of said electric motor via said coupling mechanism, so as to restart driving said internal combustion engine.

24. A method in accordance with claim 23, said method further comprising the steps of:

measuring elasticity of said transmission belt;

detecting the kinetic energy absorbing state of said transmission belt based on the observed elasticity of said transmission belt; and

enhancing the rate of decrease in electric motor velocity with a decrease in observed elasticity of said transmission belt.

25. A method in accordance with claim 23, said method further comprising the steps of:

measuring temperature of said transmission belt;

detecting the kinetic energy absorbing state of said transmission belt based on the observed temperature of said transmission belt; and

enhancing the rate of decrease in electric motor velocity with a decrease in observed temperature of said transmission belt.

26. A method in accordance with claim 25, said method further comprising the steps of:

measuring temperature of a cooling fluid that passed through said internal combustion engine; and

enhancing the rate of decrease in electric motor velocity with a decrease in observed temperature of the cooling fluid.

27. A method in accordance with claim 26, said method further comprising the steps of:

accumulating engine velocity or number of revolutions of said internal combustion engine from a start to a stop of driving of said internal combustion engine; and

lowering the rate of decrease in electric motor velocity with an increase in accumulated engine velocity.

28. A method in accordance with claim 26, said method further comprising the steps of:

accumulating electric motor velocity or number of revolutions of said electric motor after a stop of driving of said internal combustion engine; and

lowering the rate of decrease in electric motor velocity with an increase in accumulated electric motor velocity.

29. A method in accordance with claim 27, said method further comprising the steps of:

measuring an outside air temperature; and

enhancing the rate of decrease in electric motor velocity with an increase in observed outside air temperature.