Shift control apparatus for transmission

1. A shift control apparatus of a transmission for vehicle having an input shaft driven by an engine and an output shaft connecting with a drive wheel for automatically changing a speed ratio between said input shaft and said output shaft, comprising:

accelerator pedal depression amount detecting means for detecting a depression amount of an accelerator pedal;

road gradient detecting means for detecting a gradient of a road on which said vehicle travels;

kick-down mode establishing means for establishing a kick-down mode when said depression amount of said accelerator pedal exceeds a threshold value; and

control means for changing said threshold value at least based on said road gradient;

wherein said threshold value comprises a high value when said vehicle travels on an upgrade, compared to when said vehicle travels on an even road.

2. A shift control apparatus of a transmission for vehicle having an input shaft driven by an engine and an output shaft connecting with a drive wheel for automatically changing a speed ratio between said input shaft and said output shaft, comprising:

accelerator pedal depression amount detecting means for detecting a depression amount of an accelerator pedal;

road gradient detecting means for detecting a gradient of a road on which said vehicle travels;

kick-down mode establishing means for establishing a kick-down mode when said depression amount of said accelerator pedal exceeds a threshold value; and

control means for changing said threshold value at least based on said road gradient,

wherein said threshold value comprises a small value when said vehicle travels on a downgrade, compared to when said vehicle travels on an even road.

3. A shift control apparatus of a transmission for a vehicle having an input shaft driven by an engine and an output shaft connecting with a drive wheel for automatically changing a speed ratio between said input shaft and said output shaft, comprising:

an accelerator pedal sensor for detecting a depression amount of an accelerator pedal;

a road gradient module for detecting a gradient of a road on which said vehicle travels;

a vehicle speed detector for detecting a vehicle speed;

a kick-down mode module for establishing a kick-down mode when said depression amount of said accelerator pedal exceeds a threshold value; and

a controller for changing said threshold value based on said road gradient and said vehicle speed,

wherein said threshold value comprises a high value when said vehicle travels on an upgrade, compared to when said vehicle travels on an even road.

4. A shift control apparatus of a transmission for vehicle having an input shaft driven by an engine and an output shaft connecting with a drive wheel for automatically changing a speed ratio between said input shaft and said output shaft, comprising:

an accelerator pedal sensor for detecting a depression amount of an accelerator pedal;

a road gradient module for detecting a gradient of a road on which said vehicle travels;

a vehicle speed detector for detecting a vehicle speed;

a kick-down mode module for establishing a kick-down mode when said depression amount of said accelerator pedal exceeds a threshold value; and

a controller for changing said threshold value based on said road gradient and said vehicle speed,

wherein said threshold value comprises a small value when said vehicle travels on a downgrade, compared to when said vehicle travels on an even road.

5. A shift control apparatus of a transmission for vehicle for automatically changing a speed ratio of the transmission, comprising:

an accelerator pedal sensor for detecting a depression amount of an accelerator pedal;

a road gradient sensor for detecting a gradient of a road on which said vehicle travels;

a kick-down module for establishing a kick-down mode when said depression amount of said accelerator pedal exceeds a threshold value; and

a controller for changing said threshold value at least based on said road gradient;

wherein said threshold value comprises a high value when said vehicle travels on an upgrade, compared to when said vehicle travels on an even road.

6. The apparatus according to claim 5 , wherein said accelerator pedal sensor comprises a sensor attached to said accelerator pedal.

7. The apparatus according to claim 5 , wherein said kick-down module determines whether a present traveling mode of said vehicle comprises kick-down mode.

8. The apparatus according to claim 5 , wherein said kick-down module determines whether said present traveling mode comprises said kick-down mode by:

reading an accelerator pedal operating amount calculated from an output signal of said accelerator pedal sensor, a vehicle speed and an engine speed;

obtaining said gradient from said road gradient sensor;

calculating said threshold value based on said vehicle speed and said gradient;

comparing said accelerator pedal depression amount with said threshold value to determine if said kick-down mode is permitted.

9. The apparatus according to claim 7 , wherein said kick-down module determines whether said present traveling mode could be kick-down mode by:

determining whether said kick-down mode is permitted to be canceled by determining if said accelerator pedal depression amount decreases compared to a previous accelerator pedal depression amount; and

canceling said kick-down mode.

10. The apparatus according to claim 8 , further comprising:

determining whether said kick-down mode is permitted to be canceled by determining if said accelerator pedal depression amount decreases compared to a previous accelerator pedal depression amount; and

canceling said kick-down mode.

11. The apparatus according to claim 8 , further comprising:

a crank angle sensor for detecting said engine speed.

12. The apparatus according to claim 8 , further comprising:

a vehicle speed detector for detecting said vehicle speed.

13. A shift control apparatus of a transmission for a vehicle for automatically changing a speed ratio of the transmission comprising:

an accelerator pedal sensor for detecting a depression amount of an accelerator pedal;

a road gradient sensor for detecting a gradient of a road on which said vehicle travels;

a kick-down module for establishing a kick-down mode when said depression amount of said accelerator pedal exceeds a threshold value; and

a controller for changing said threshold value at least based on said road gradient;

wherein said threshold value comprises a small value when said vehicle travels on a downgrade, compared to when said vehicle travels on an even road.

14. The apparatus according to claim 13 , wherein said accelerator pedal sensor comprises a sensor attached to said accelerator pedal.

15. The apparatus according to claim 13 , wherein said kick-down module determines whether a present traveling mode of said vehicle comprises a kick-down mode.

16. The apparatus according to claim 15 , wherein said kick-down module determines whether said present traveling mode comprises said kick-down mode by:

reading an accelerator pedal operating amount calculated from an output signal of said accelerator pedal sensor, a vehicle speed and an engine speed;

obtaining said gradient from said road gradient sensor;

calculating said threshold value based on said vehicle speed and said gradient;

comparing said accelerator pedal depression amount with said threshold value to determine if said kick-down mode is permitted.

17. The apparatus according to claim 15 , wherein said kick-down module determines whether said present traveling mode comprises said kick-down mode by:

determining whether said kick-down mode is permitted to be canceled by determining if said accelerator pedal depression amount decreases compared to a previous accelerator pedal depression amount; and

canceling said kick-down mode.

18. The apparatus according to claim 16 , further comprising:

determining whether said kick-down mode is permitted to be canceled by determining if said accelerator pedal depression amount decreases compared to a previous accelerator pedal depression amount; and

canceling said kick-down mode.

19. The apparatus according to claim 16 , further comprising:

a crank angle sensor for detecting said engine speed.

20. The apparatus according to claim 16 , further comprising:

a vehicle speed detector for detecting said vehicle speed.

21. A method of controlling a kick-down mode, comprising:

sensing an amount of road gradient;

calculating a kick-down mode threshold based on said road gradient; and

establishing a kick-down mode when an amount of an accelerator pedal depression exceeds said threshold value,

wherein said kick-down mode threshold comprises a high value when a vehicle travels on an upgrade, compared to when said vehicle travels on an even road.

22. A method of controlling a kick-down mode, comprising:

sensing an amount of road gradient;

calculating a kick-down mode threshold based on said road gradient; and

establishing a kick-down mode when an amount of an accelerator pedal depression exceeds said threshold value,

wherein said kick-down mode threshold comprises a small value when a vehicle travels on a downgrade, compared to when said vehicle travels on an even road.

23. The method of claim 21 , further comprising:

sensing said amount of an accelerator pedal depression; and

comparing said amount of accelerator pedal depression with said kick-down mode threshold.

24. The method of claim 22 , further comprising:

sensing said amount of an accelerator pedal depression; and

comparing said amount of accelerator pedal depression with said kick-down mode threshold.

25. An apparatus for controlling shifting for transmission, comprising:

a gradient module that calculates a current gradient;

a kick-down mode threshold module that calculates a kick-down mode threshold based on said gradient; and

a kick-down mode module for establishing a kick-down mode when a depression amount of an accelerator pedal exceeds said kick-down mode threshold,

wherein said kick-down mode threshold comprises a high value when a vehicle travels on an upgrade, compared to when said vehicle travels on an even road.

26. An apparatus for controlling shifting for transmission, comprising:

a gradient module that calculates a current gradient;

a kick-down mode threshold module that calculates a kick-down mode threshold based on said gradient; and

a kick-down mode module for establishing a kick-down mode when a depression amount of an accelerator pedal exceeds said kick-down mode threshold,

wherein said kick-down mode threshold comprises a small value when a vehicle travels on a downgrade, compared to when said vehicle travels on an even road.