Transmission control apparatus for an automatic transmission

• US 6,811,515 B2
• Filed: 04/28/2003
• Issued: 11/02/2004
• Est. Priority Date: 11/25/1996
• Status: Expired due to Fees

• Current Assignee: Hitachi Car Engineering Company Limited (Hitachi, Ltd.), Hitachi, Ltd.
• Original Assignee: Hitachi Car Engineering Company Limited (Hitachi, Ltd.), Hitachi, Ltd.
• Inventors: Sato, Kazuhiko, Ibamoto, Masahiko, Kuroiwa, Hiroshi, Shioya, Makoto
• Primary Examiner(s): ESTREMSKY, SHERRY LYNN
• Application Number:
  US10/423,926
• Publication Number:
  US 20040014558A1
• Time in Patent Office: 554 Days
• Field of Search: 477/46, 477/48, 477/49, 477/97, 477/901, 701/57, 701/60, 701/61, 701/65
• US Class Current: 477/97
• CPC Class Codes: F16H 2061/0015 Transmission control for optimising fuel consumptions
• CPC Class Codes: F16H 61/66254 controlling of shifting being influenced by a signal derived from the engine and the main coupling
• CPC Class Codes: Y10S 477/901 Control signal is slope

Abstract

The improved CVT control apparatus for a vehicle is disclosed. By using the CVT control apparatus, it becomes possible that the drive feeling is constant independently of a running state, the vehicle is accelerated as the driver'"'"'s intention if accelerated due to the actuation of an accelerator pedal, and the run of the vehicle is performed so as to improve the fuel consumption rate if the acceleration is not required.

By always calculating a correct driving torque, the transmission gear ratio is calculated to obtain the target driving torque set based on the amount of actuation of an accelerator pedal, and the obtained target driving torque is corrected by the gradient of a road obtained from the calculated driving torque. Further, the gear ratio which aims at the improvement of acceleration and the gear ratio which aims at the improvement of the rate of fuel consumption are weighted and combined with each other, and the optimum gear ratio is obtained by using fuzzy inference.

Claims

1. A control apparatus for an automatic transmission of a vehicle including a gear ratio calculating unit for controlling the automatic transmission to transfer an output of an engine of the vehicle to driven wheels, for changing a gear ratio, and for calculating the gear ratio, and a speed- change control unit for controlling the gear ratio based on a result of the calculation, comprising:

a target driving torque generating unit for generating a value of a target driving torque based on an adaptation coefficient indicative of a vehicle running state and a vehicle speed,

a driving torque calculating unit for calculating a value of driving torque based on the adaptation coefficient, vehicle speed and engine speed,

a correcting unit for obtaining a correcting value for correcting the value of the target driving torque by deriving a difference between the driving torque calculated by said driving torque calculating unit and the target driving torque, and

a gear-ratio-change-command unit for generating a gear-ratio-change-command based on the correcting value obtained by said correcting unit, and for commanding a change in the gear ratio,

wherein said speed-change control unit changes the gear ratio based on the gear-ratio-change-command from the gear-ratio-change-command unit.

2. A control apparatus for an automatic transmission of a vehicle according to claim 1, wherein the value of the target driving torque is determined from predetermined target driving torque characteristics based on the adaptation coefficient and the vehicle speed.

3. A control apparatus for an automatic transmission of a vehicle according to claim 1, wherein the adaptation coefficient is an opening of a throttle valve for controlling an amount of air taken into the engine of the vehicle.

4. A control apparatus for an automatic transmission of a vehicle including a gear ratio calculating unit for controlling the automatic transmission to transfer an output of an engine of the vehicle to driven wheels, for changing a gear ratio, and for calculating the gear ratio, and a speed-change control unit for controlling the gear ratio based on a result of the calculation, comprising:

a road gradient calculating unit for calculating a gradient of a road,

a target driving torque generating portion for generating a value of a target driving torque based on an adaptation coefficient indicative of a vehicle running state, a vehicle speed and the road gradient,

a driving torque calculating unit for calculating a value of driving torque based on the adaptation coefficient, vehicle speed and engine speed,

a correcting unit for obtaining a correcting value for correcting the value of the target driving torque by deriving a difference between the driving torque calculated by said driving torque calculating unit and the target driving torque, and

a gear-ratio-change-command means for generating a gear-ratio-change-command based on the correcting value obtained by said correcting unit and for commanding a change in the gear ratio,

wherein said speed-change control unit changes the gear ratio based on the gear-ratio-change-command from the gear-ratio-change-command means.

5. A control apparatus for an automatic transmission of a vehicle according to claim 4, wherein the value of the target driving torque is determined from predetermined target driving torque characteristics based on the adaptation coefficient, the vehicle speed and the road gradient.

6. A control apparatus for an automatic transmission of a vehicle according to claim 4, wherein the road gradient is calculated based on vehicle speed and the value of the driving torque calculated by the driving torque calculating unit.

7. A control apparatus for an automatic transmission of a vehicle including a gear ratio calculating unit for controlling the automatic transmission to transfer an output of an engine of the vehicle to driven wheels, for changing a gear ratio, and for calculating the gear ratio, and a speed-change control unit for controlling the gear ratio based on a result of the calculation, comprising:

a fuel consumption calculating unit for calculating an amount of fuel consumption,

a first gear-ratio-change-command unit for generating a first gear-ratio-change-command, based on the fuel consumption amount calculated by the fuel consumption calculating unit,

a road gradient calculating unit for calculating a gradient of a road,

a target driving torque generating portion for generating a value of target driving torque based on an adaptation coefficient indicative of a vehicle running state, a vehicle speed and the road gradient,

a driving torque calculating unit for calculating a value of driving torque based on the adaptation coefficient, vehicle speed, engine speed and a turbine speed,

a second gear-ratio-change-command unit for correcting the target driving torque by deriving a difference between the driving torque calculated by said driving torque calculating unit and the target driving torque, and generating a second gear-ratio-change-command,

a means for recognizing driver'"'"'s intention and running environment based on the adaptation coefficient and the vehicle speed, and

a fuzzy inference means for generating a third gear-ratio-change-command based on an output value of the first gear-ratio-change-command unit, an output value of the second gear-ratio-change-command unit, an output value of the means for recognizing driver'"'"'s intention and running environment and a predetermined rule for fuzzy inference,

wherein said speed-change control unit changes the gear ratio based on the third gear-ratio-change-command generated by the fuzzy inference means.

8. A control apparatus for an automatic transmission of a vehicle according to claim 7, wherein the fuzzy inference is performed by weighting the first gear-ratio-change-command as compared with the second gear-ratio-change-command.

9. A method of controlling an automatic transmission for a vehicle, in which a gear ratio of the automatic transmission is changed based on conditions for speed-change, in which a load of an engine for the vehicle is set as a parameter, comprising the steps of:

changing conditions for speed-change based on an operation mode selected from at least two modes including a mode which aims at improvement of acceleration and a mode which aims at improvement of a fuel consumption rate, and

correcting a value of a target driving torque by using a driving torque obtained based on a value indicative of a running state of the vehicle, a vehicle speed, an engine speed and a turbine speed of a torque converter for the automatic transmission,

wherein, in area of a low load, a magnitude of variation of the engine speed relative to variation of engine load is set larger in the mode which aims at improvement of acceleration than in the mode which aims at improvement of the fuel consumption rate, and wherein, in an area of a high load, the magnitude of variation of the engine speed relative to variation of engine load is set larger in the mode which aims at improvement of the fuel consumption rate than in the mode which aims at improvement of acceleration.

10. A method of controlling an automatic transmission for a vehicle according to claim 9, further comprising the steps of:

inferring an adaptation coefficient based on a predetermined rule for fuzzy inference, and

changing conditions of speed-change by using the fuzzy inference for determining the adaptation coefficient based on the extent of the increase and decrease of the inferred adaptation coefficient.

11. A method of controlling an automatic transmission for a vehicle according to claim 9, wherein conditions of speed-change are changed by using the fuzzy inference for inferring the extent of the increase and decrease of a an adaptation coefficient and determining the adaptation coefficient based on the extent of an increase and decrease.

12. A control apparatus for an automatic transmission of a vehicle which has an accelerator physically linked with a throttle valve for adjusting an output of an internal combustion engine, a transmission speed ratio calculating unit for controlling the automatic transmission to transfer an output of the engine to driven wheels, and for changing a transmission speed ratio, and for calculating the transmission speed ratio, and a speed-change control unit for controlling the transmission speed ratio based on a result of a calculation, comprising:

a target driving torque generating unit for generating a value of a target driving torque based on an adaptation coefficient indicative of a vehicle running state and a vehicle speed,

a driving torque calculating unit for calculating a value of driving torque based on the adaptation coefficient, vehicle speed and engine speed,

a correcting unit for obtaining a correcting value for correcting the value of the target driving torque based on the value of the driving torque calculated by said driving torque calculating unit and correcting the target driving torque, and

a transmission speed-ratio-change-command unit for generating a transmission speed-ratio-change-command based on the correcting value obtained by said correcting unit and for commanding a change in the transmission speed ratio,

wherein said speed-change control unit changes the transmission speed ratio based on the transmission speed-ratio-change-command from the transmission speed-ratio-change-command unit.

13. A control apparatus for an automatic transmission of a vehicle according to claim 12, wherein the value of the target driving torque is determined from predetermined target driving torque characteristics based on the adaptation coefficient and the vehicle speed.

14. A control apparatus for an automatic transmission of a vehicle according to claim 12, wherein the adaptation coefficient is an opening of a throttle valve for controlling an amount of air taken into the engine of the vehicle.

15. A control apparatus for an automatic transmission of a vehicle which has an accelerator physically linked with a throttle valve for adjusting an output of an internal combustion engine, a transmission speed ratio calculating unit for controlling the automatic transmission to transfer an output of the engine to driven wheels, and for changing a transmission speed ratio, and for calculating the transmission speed ratio, and a speed-change control unit for controlling the transmission speed ratio based on a result of the calculation, comprising:

a road gradient calculating unit for calculating a gradient of a road,

a target driving torque generating portion for generating a value of target driving torque based on an adaptation coefficient indicative of a vehicle running state, a vehicle speed and the road gradient,

a driving torque calculating unit for calculating a value of driving torque based on the adaptation coefficient, vehicle speed and engine speed,

a correcting unit for obtaining a correcting value for correcting the value of the target driving torque based on the value of the driving torque calculated by said driving torque calculating unit and correcting the target driving torque, and

a transmission speed-ratio-change-command unit for generating a transmission speed-ratio-change-command based on the correcting value obtained by said correcting unit and for commanding a change in the transmission speed ratio,

wherein said speed-change control unit changes the transmission speed ratio based on the transmission speed-ratio-change-command from the transmission speed-ratio-change-command unit.

16. A control apparatus for an automatic transmission of a vehicle according to claim 15, wherein the value of the target driving torque is determined from predetermined target driving torque characteristics based on the adaptation coefficient, the vehicle speed and the road gradient.

17. A control apparatus for an automatic transmission of a vehicle according to claim 15, wherein the road gradient is calculated based on vehicle speed and the value of the driving torque calculated by the driving torque calculating unit.

18. A control apparatus for an automatic transmission of a vehicle including a gear ratio calculating unit for controlling the automatic transmission to transfer an output of an engine of the vehicle to driven wheels after changing the gear ratio, and calculating the gear ratio, and a speed-change control unit for controlling the gear ratio based on the result of the calculation, comprising:

a target driving torque generating unit for generating a value of the target driving torque based on an adaptation coefficient indicative of a vehicle running state and a vehicle speed,

a driving torque calculating unit for calculating a value of driving torque based on the adaptation coefficient, the vehicle speed and the engine speed,

a correcting unit forming a feedback system for driving torque taking gear ratio as a control amount, and

a gear-ratio-change-command unit for generating a gear-ratio-change-command based on the correcting value obtained by said correcting unit and commanding the change in the gear ratio,

wherein said speed-change control unit changes the gear ratio based on the gear-ratio-change-command from the gear-ratio-change-command unit.

19. A control apparatus for an automatic transmission of a vehicle including a gear ratio calculating unit for controlling the automatic transmission to transfer an output of an engine of the vehicle to driven wheels, for changing gear ratio, and for calculating the gear ratio, and a speed-change control unit for controlling the gear ratio based on a result of the calculation, comprising:

a road gradient calculating unit for calculating gradient of a road,

a target driving torque generating portion for generating a value of a target driving torque based on an adaptation coefficient indicative of a vehicle running state, a vehicle speed and the road gradient,

a driving torque calculating unit for calculating a value of driving torque based on the adaptation coefficient, vehicle speed and engine speed,

a correcting unit forming a feedback system for driving torque taking gear ratio as a control amount, and

a gear-ratio-change-command means for generating a gear-ratio-change-command based on the correcting value obtained by said correcting unit and for commanding change in the gear ratio,

wherein said speed-change control unit changes the gear ratio based on the gear-ratio-change-command from the gear-ratio-change-command means.

20. A method of controlling an automatic transmission for a vehicle, in which a gear ratio of the automatic transmission is changed based on conditions for speed-change, in which a load of an engine for the vehicle is set as a parameter, comprising the steps of:

changing conditions for speed-change based on an operation mode selected from at least two modes including a mode which aims at improvement of acceleration and a mode which aims at the improvement of fuel consumption rate, and

forming a feedback system for driving torque taking gear ratio as a control amount,

wherein, the area of a low load, a magnitude of variation of the engine speed relative to variation of the engine load is set larger in the mode which aims at the improvement of acceleration maybe larger than in a mode which aims at improvement of fuel consumption rate, and wherein, in an area of a high load, the magnitude of variation of the engine speed relative to variation of engine load is set larger in the mode which aims at improvement of the fuel consumption rate than in the mode which aims at improvement of acceleration at an area of a high load.

21. A control apparatus for an automatic transmission of a vehicle which has an accelerator physically linked with a throttle valve for adjusting an output of an internal combustion engine, a transmission speed ratio calculating unit for controlling the automatic transmission to transfer an output of the engine to driven wheels, and for changing a transmission speed ratio, and for calculating the transmission speed ratio, and a speed-change control unit for controlling the transmission speed ratio based on the result of a calculation, comprising:

a target driving torque generating unit for generating a value of a target driving torque based on an adaptation coefficient indicative of a vehicle running state and a vehicle speed,

a driving torque calculating unit for calculating a value of driving torque based on the adaptation coefficient, vehicle speed and engine speed,

a correcting unit forming a feedback system for driving torque taking gear ratio as a control amount, and

a transmission speed ratio-change command unit for generating a transmission speed ratio-change command based on the correcting value obtained by said correcting unit and for commanding the change in the transmission speed ratio,

wherein said speed-change control unit changes the transmission speed ratio based on the transmission speed ratio-change command from the transmission speed-ratio-change command unit.

22. A control apparatus for an automatic transmission of a vehicle which has an accelerator physically linked with a throttle valve for adjusting an output of an internal combustion engine, a transmission speed ratio calculating unit for controlling the automatic transmission to transfer an output of the engine to driven wheels, and for changing a transmission speed ratio, and for calculating the transmission speed ratio, and a speed-change control unit for controlling the transmission speed ratio based on a result of the calculation, comprising:

a road gradient calculating unit for calculating a gradient of a road;

a target driving torque generating portion for generating a value of the target driving torque based on an adaptation coefficient indicative of a vehicle running state, a vehicle speed and the road gradient,

a driving torque calculating unit for calculating a value of driving torque based on the adaptation coefficient, vehicle speed and engine speed,

a correcting unit forming a feedback system for driving torque taking gear ratio as a control amount, and

a transmission speed-ratio-change-command unit for generating a transmission speed-ratio-change-command based on the correcting value obtained by said correcting unit and for commanding a change in the transmission speed ratio,

wherein said speed-change control unit changes the transmission speed ratio based on the transmission speed-ratio-command unit.