Patent ID: 6125317
Filing Date: 2000-09-26
Classification: B60K,B60W,F16H

Abstract:
A method for controlling a transfer case having a neutral state and a plurality of drive modes in an automatic four-wheel-drive driveline for a motor vehicle having an engine drivably connected to the transfer case, a MSS having a plurality of positions for selecting the drive modes, an upshift relay and a downshift relay to energize a motor to effect a shift of the transfer case to the selected drive mode, and an encoder for detecting a value corresponding to the rotational position of the motor, the method comprising:sensing if the encoder has lost power;upon sensing the encoder has lost power:comparing a current MSS position with a MSS position prior to losing power to the encoder;if the current and prior MSS positions differ, determining the most recent valid MSS position;determining whether the upshift and downshift relays are turned ""on"";determining the direction of rotation of the motor;determining the desired motor destination;determining the direction in which to rotate the motor; anddetermining the maximum time to allow the motor to rotate to achieve the desired destination.