Shift control method for automatic transmission

• US 6,500,091 B2
• Filed: 12/29/2000
• Issued: 12/31/2002
• Est. Priority Date: 06/26/2000
• Status: Expired due to Fees

• Current Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Original Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Inventors: Yeo, Chang-Gi
• Primary Examiner(s): Lorence, Richard M.
• Assistant Examiner(s): HO, HA DINH
• Application Number:
  US09/749,942
• Publication Number:
  US 20010056007A1
• Time in Patent Office: 732 Days
• Field of Search: 477/97, 477/900, 477/901, 701/56, 701/55, 701/65, 701/66
• US Class Current: 477/97
• CPC Class Codes: F16H 2059/142 of driving resistance calculated from weight, slope, or the like
• CPC Class Codes: F16H 59/66 Road conditions, e.g. slope, slippery
• CPC Class Codes: F16H 61/0213 characterised by the method for generating shift signals
• CPC Class Codes: Y10S 477/90 Control signal is vehicle weight
• CPC Class Codes: Y10S 477/901 Control signal is slope

Abstract

A shift control method for an automatic transmission while a vehicle runs up a slope while towing a trailer includes the steps of determining if present shift lever position indicates a driving range 2, calculating weight-slope resistance if the shift lever position indicates the driving range 2, determining if the weight-slope resistance is greater than a threshold weight-slope resistance, measuring time duration during which the weight-slope resistance is maintained over the threshold value if the weight-slope resistance is greater than the threshold weight-slope resistance, determining if the time duration is longer than a threshold time, converting a present normal shift pattern into a trailer-towing shift pattern if the time duration is longer than a threshold time, and returning the trailer-towing shift pattern to the normal shift pattern if the weight-slope resistance becomes equal to or less than the threshold weight-slope resistance and this condition is maintained over a second threshold time.

Claims

1. A shift control method for an automatic transmission while a vehicle runs up a slope while towing a trailer comprising the steps of:

determining if present shift lever position indicates a driving range 2;

calculating weight-slope resistance if the shift lever position indicates the driving range 2;

determining if the weight-slope resistance is greater than a threshold weight-slope resistance;

measuring a time duration during which the weight-slope resistance is maintained over the threshold value when the weight-slope resistance is greater than the threshold weight-slope resistance;

determining if the time duration is longer than a threshold time; and

converting a present normal shift pattern into a trailer-towing shift pattern when the time duration is longer than a threshold time.

2. The shift control method of claim 1 wherein when the weight-slope resistance becomes equal to or less than the threshold weight-slope resistance and this condition is maintained over a second threshold time, the trailer-towing shift pattern is returned to the normal shift pattern.

3. A shift control method for an automatic transmission while a vehicle runs up a slope and tows a trailer comprising the steps of:

a) determining if present shift lever position indicates a driving range 2;

b) calculating weight-slope resistance when the present shift lever position indicates the driving range 2;

c) determining if the weight-slope resistance is greater than a threshold weight-slope resistance;

d) starting a timer when the weight-slope resistance is greater than the threshold weight-slope resistance;

e) measuring a time duration during which the weight-slope resistance is greater than the threshold weight-slope resistance;

f) determining if the time duration is longer than a threshold time duration;

g) determining that the vehicle runs up a slope when the time duration is longer than the threshold time duration; and

h) converting a present normal shift pattern into a trailer-towing shift pattern.

4. The shift control method of claim 3 further comprising the steps of:

i) determining if the weight-slope resistance is equal to or less than a second threshold weight-slope resistance;

j) starting the timer if the weight-slope resistance is equal to or less than the second threshold weight-slope resistance;

k) measuring time duration during which the weight-slope resistance is equal to or less than the second threshold weight-slope resistance;

l) determining if the time duration is longer than a second threshold time duration;

m) determining that the vehicle is not running up a slope when the time duration is longer than a second threshold time duration; and

n) returning the trailer-towing shift pattern to the normal shift pattern.