Control method for automobile transmissions

• US 7,349,784 B2
• Filed: 12/31/2003
• Issued: 03/25/2008
• Est. Priority Date: 07/10/2003
• Status: Expired due to Fees

• Current Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Original Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Inventors: Lee, Jung-Suk
• Primary Examiner(s): Black; Thomas
• Assistant Examiner(s): Behncke; Christine M
• Application Number:
  US10/750,660
• Publication Number:
  US 20050010349A1
• Time in Patent Office: 1,546 Days
• Field of Search: 701/51, 701/62, 701/64, 701/95, 701/67, 192/219.1, 192/3.58, 477/125, 477/126, 477/110, 477/79, 477/116, 475/119, 475/133
• US Class Current: 701/62
• CPC Class Codes: F16H 2061/165 Preventing reverse gear shifts if vehicle speed is too high for safe shifting
• CPC Class Codes: F16H 61/12 Detecting malfunction or potential malfunction, e.g. fail safe in control of hydrostatic gearing F16H61/4192; Circumventing or fixing failures
• CPC Class Codes: F16H 61/16 Inhibiting or initiating shift during unfavourable conditions, e.g. preventing forward reverse shift at high vehicle speed, preventing engine over speed unintentional control input F16H61/18

Abstract

A control method for automatic transmissions wherein a reverse motion condition in the neutral or drive ranges, caused by burning or the like in the operating devices of the automatic transmission, can be automatically detected to prevent an unwanted reverse motion of a vehicle from occurring, thereby enhancing the safety of the automatic transmission and improving the running stability of the vehicle.

Claims

1. A control method for an automatic transmission, comprising:

determining whether an engine is operating;

checking a shift range selection state when the engine is in a normal operation;

determining whether operating elements that commonly operate at N, D and R ranges are operating when said shift range is in N or D range, or in the midst of N-D change;

calculating an inspection speed by multiplying an output axle speed of the automatic transmission by a reversing gear ratio when said common operating elements are operating;

determining whether a difference between an input axle speed of the automatic transmission and the inspection speed is within a predetermined range for a prescribed period of time; and

stopping operation of the common operating elements when it is determined that a vehicle is reversing as a result of the determination in, the previous step.

2. The method as defined in claim 1, wherein the range checking step comprises:

ascertaining whether said shift range is in N range or D range; and

ascertaining whether said shift range is in the midst of N-D change control.

3. The method as defined in claim 1, further comprising a step of determining whether the vehicle is running at a predetermined speed between the operation element checking step and the inspection speed calculating step, and carrying out the inspection speed calculating step if the vehicle speed is within a predetermined speed.