Method of controlling a synchronizer actuator fork of a transmission

Patent metadata

Field	Value
Publication number	US-2016146341-A1
Application number	US-201414549584-A
Country	US
Kind code	A1
Filing date	Nov 21, 2014
Priority date	Nov 21, 2014
Publication date	May 26, 2016
Grant date	—

Abstract

A method and system for controlling movement of an actuator fork of a transmission through a pre-synchronization phase of a synchronization event at a pre-synchronization fork velocity includes adjusting the level of fluid pressure applied to an actuator operatively attached to the actuator fork to control the pre-synchronization fork velocity within a predetermined range of a velocity target. The method determines, via a controller, the fork velocity during the pre-synchronization phase of a current synchronization event, compares the determined fork velocity to a velocity target, and adjusts the pressure level of fluid applied to an actuator piston of the actuator to control the velocity of the actuator fork within a predetermined range defined by the velocity target during a subsequent pre-synchronization phase. The velocity target may be defined for a shift type, such as a fast or slow shift, where the shift type is determined by the controller.

First claim

1 . A method of controlling a transmission including a shaft, the shaft having a synchronizer and a gear mounted thereon, the method comprising:
moving, at a fork velocity, an actuator fork of the synchronizer in a gear engagement direction, through a pre-synchronization phase of a synchronization event; wherein:
movement of the actuator fork is controlled by an actuator including an actuator piston;
the actuator is operatively connected to the actuator fork and actuable to move the actuator fork in the gear engagement direction by applying a fluid pressure to the actuator piston at an applied fluid pressure level;
the applied fluid pressure is commanded by a controller in communication with the actuator; and
the fork velocity is defined by the applied fluid pressure level;
determining, via the controller, the fork velocity; comparing, via the controller, the fork velocity to a fork velocity target; and adjusting, via the controller, the applied fluid pressure level when the fork velocity and the velocity target are not equal.

2 . The method of claim 1 , further comprising:
comparing, via the controller, the fork velocity to a predetermined range defined by the velocity target; maintaining the applied fluid pressure level when the fork velocity is within the predetermined range; and adjusting the applied fluid pressure level when the fork velocity is outside of the predetermined range.

3 . The method of claim 2 , further comprising:
adjusting the applied fluid pressure level by a predetermined amount when the fork velocity is outside the predetermined range; wherein the predetermined amount is defined by the difference between the fork velocity and the velocity target.

4 . The method of claim 1 , further comprising:
selecting, via the controller, a look-up table; wherein the look-up table provides a predetermined amount to adjust the applied fluid pressure according to the difference between the fork velocity and the velocity target; and determining the predetermined amount to adjust the applied fluid pressure from the look-up table.

5 . The method of claim 1 , further comprising:
commanding, via the controller, a shift including the synchronization event; wherein:
the commanded shift is characterized by a shift type;
the shift type is one of a plurality of shift types executable by the transmission; and
the velocity target is defined by the shift type.

6 . The method of claim 5 , further comprising:
selecting, via the controller, a look-up table from a plurality of look-up tables, each corresponding to a respective one of the plurality of shift types; wherein the selected look-up table corresponds to the shift type of the commanded shift and provides a predetermined amount to adjust the applied fluid pressure according to the difference between the fork velocity and the velocity; and determining the predetermined amount to adjust the applied fluid pressure from the selected look-up table.

7 . The method of claim 1 , wherein:
moving the actuator fork through a pre-synchronization phase comprises moving the actuator fork in the gear engagement direction from a first fork position to a second fork position; the method further comprising:
sensing, via at least one fork position sensor in communication with the controller, the actuator fork at the first fork position at a first time;
outputting a first signal to the controller at the first time;
sensing, via at least one fork position sensor, the actuator fork at the second fork position; and
outputting a second signal to the controller at the second time.

8 . The method of claim 7 , further comprising:
determining the fork velocity using the first and second fork positions and the first and second times.

9 . The method of claim 7 , further comprising:
time stamping, via the controller, the first signal with a first time stamp; time stamping, via the controller, the second signal with a second time stamp; and determining the fork velocity using the first and second fork positions and the first and second time stamps.

10 . The method of claim 9 , further comprising:
storing the first and second timestamps to a memory in communication with the controller.

11 . The method of claim 7 , wherein:
the actuator fork is operatively attached to a synchronizer sleeve; and the first position is defined by a neutral position of the actuator fork relative to the synchronizer sleeve.

12 . The method of claim 7 , further comprising:
monitoring, via the controller, synchronizer slip of the synchronizer during the synchronization event; wherein during the pre-synchronization phase the synchronizer slip is characterized by a first rate of slip and a second rate of slip; and wherein the second position is defined by a change in the rate of synchronizer slip from the first rate to the second rate.

13 . A method of controlling a transmission including a shaft, the shaft having a synchronizer and a gear mounted thereon, the method comprising:
commanding, via a controller, application of a fluid pressure at an applied fluid pressure level to an actuator piston of an actuator; applying the fluid pressure to the actuator piston at an applied fluid pressure level to move an actuator fork operatively connected to the actuator in a gear engagement direction from a first pre-synchronization position to a second pre-synchronization position; wherein the actuator fork is moved from the first pre-synchronization position to the second pre-synchronization position at a fork velocity defined by the applied fluid pressure level; measuring an elapsed time to move the actuator fork from the first pre-synchronization position to the second pre-synchronization position; determining the fork velocity of the fork using the first and second pre-synchronization positions and the elapsed time; comparing, via the controller, the fork velocity to a fork velocity target; and adjusting, via the controller, the applied fluid pressure level when the fork velocity and the velocity target are not equal.

14 . The method of claim 1 , further comprising:
comparing, via the controller, the fork velocity to a predetermined range defined by the velocity target; maintaining the applied fluid pressure level when the fork velocity is within the predetermined range; and adjusting the applied fluid pressure level by a predetermined amount when the fork velocity is outside of the predetermined range; wherein the predetermined amount is defined by the difference between the fork velocity and the velocity target.

15 . The method of claim 13 , further comprising:
sensing, via at least one fork position sensor in communication with the controller, the actuator fork at the first fork position at a first time; sensing, via at least one fork position sensor, the actuator fork at the second fork position; and determining the elapsed time using the first and second times.

16 . The method of claim 13 , further comprising:
outputting, via at least one fork position sensor in communication with the controller, a first signal to the controller when the at least one fork position sensor senses the actuator fork at the first fork position; time stamping, via the controller, the first signal with a first time stamp; outputting, via the at least one fork position sensor in communication with the controller, a second signal to the controller when the at least one fork position sensor senses the actuator fork at the second fork position; time stamping, via the controller, the second signal with a second time stamp;

Assignees

• Gm Global Tech Operations Inc

Inventors

• Hoefflin Glenn W
• Truong Minh Q
• Weingartz Christopher Jay

Classifications

• F16H61/30 Primary

  Hydraulic {or pneumatic} motors {or related fluid control means} therefor · CPC title

• F16H2061/2823

  Controlling actuator force way characteristic, i.e. controlling force or movement depending on the actuator position, e.g. for adapting force to synchronisation and engagement of gear clutch · CPC title

• F16H63/32 Primary

  Gear shift yokes, {e.g. shift forks} · CPC title

• F16H61/0204

  for gearshift control, e.g. control functions for performing shifting or generation of shift signal · CPC title

• F16H2306/00

  Shifting · CPC title