Shift control method of automatic transmission

• US 7,765,047 B2
• Filed: 12/26/2006
• Issued: 07/27/2010
• Est. Priority Date: 04/07/2006
• Status: Expired due to Fees

• Current Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Original Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Inventors: Yu, Pyung Hwan
• Primary Examiner(s): To; Tuan C
• Application Number:
  US11/646,071
• Publication Number:
  US 20070118267A1
• Time in Patent Office: 1,309 Days
• Field of Search: 701/57, 701/51, 701/67, 701/58, 702/154, 477/43, 477/39, 477/121, 477/125
• US Class Current: 701/57
• CPC Class Codes: F16H 2059/663 Road slope
• CPC Class Codes: F16H 2061/0081 Fuzzy logic
• 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

Abstract

A shift control method of an automatic transmission includes the steps of: determining whether a road has a gradient; calculating road gradient in real time; filtering the gradient; controlling shifting according to the greater of calculated and filtered gradients if the calculated gradient is negative; and controlling shifting according to the calculated gradient if the calculated gradient is positive.

Claims

1. A shift control method of an automatic transmission comprising:

a step for inputting an opening amount of a throttle and a speed of a vehicle;

a gradient determining step for determining whether a road has a gradient according to a change in the opening amount of the throttle when an acceleration pedal of the vehicle is depressed;

a gradient calculating step for calculating the gradient of the road in real time if the road is determined to have the gradient, and outputting a calculated gradient;

a gradient filtering step for filtering the calculated gradient and outputting a filtered gradient; and

a first shift controlling step for comparing the calculated gradient to the filtered gradient, outputting a greater gradient, and controlling shifting according to the greater gradient, the opening amount of the throttle, and the speed of the vehicle.

2. The method of claim 1, wherein the first shift controlling step is performed only if the calculated gradient is negative.

3. The method of claim 2, further comprising a second shifting controlling step for controlling shifting according to the calculated gradient if the calculated gradient is positive.

4. The method of claim 3, wherein the first shift controlling step is performed when the calculated gradient changes to negative after the second shift controlling step is performed.

5. The method of claim 1, wherein the gradient filtering step further comprises a step for averaging a plurality of calculated gradients calculated during a predetermined time period.

6. The method of claim 1, wherein the gradient calculating step further comprises a step for calculating the gradient based on a difference between acceleration on a flat road and that on the road.

7. The method of claim 3, wherein the second shift controlling step further comprises a step for inputting a throttle opening and a vehicle speed.

8. The method of claim 7, wherein the second shift controlling step further comprises a step for fuzzy logic that determines a shift pattern based on the calculated gradient, the throttle opening, and the vehicle speed.