Piston Actuated Split Input Transmission Synchronizer

Abstract

A piston actuated synchronizer system for a split torque transmission where the piston is attached directly to the synchronizer shift collar on the synchronizer centerline to provide the required actuation in a small volume of space and resolve fork and rod deflection issues seen on other synchronizers that use such a system. The piston is pressure applied and spring released. This design also uses a displacement sensor to monitor synchronizer engagement.

1 - 10 . (canceled) 
     
     
         11 . A process of range shifting in a split path CVT having a first input driven by an engine and a second input driven by another power source, the CVT also having an output and supporting multiple ratio ranges between the first input and the output, as well as a piston-driven synchronizer actuated via a solenoid valve, the method comprising:
 receiving an acceleration command to accelerate the split path CVT output;   causing the split path CVT output to accelerate;   determining that a shift point has been attained;   in response to determining that a shift point has been attained, reducing a torque at one or both of the first and second inputs;   activating the solenoid valve and thereby actuating the piston of the synchronizer;   determining that the range has been shifted;   increasing the torque applied at one or both of the first and second inputs to resume the prior rate of acceleration.   
     
     
         12 . The process of range shifting in a split path CVT according to  claim 11 , wherein causing the split path CVT output to accelerate further comprising causing one of the variator and the engine to accelerate. 
     
     
         13 . The process of range shifting in a split path CVT according to  claim 11 , wherein reducing a torque at one or both of the first and second inputs further comprises reducing a torque at one or both of the engine and variator. 
     
     
         14 . The process of range shifting in a split path CVT according to  claim 11 , wherein determining that the range has been shifted comprises detecting a position of a range shifting member via a position switch. 
     
     
         15 . The process of range shifting in a split path CVT according to  claim 11 , wherein increasing the torque applied at one or both of the first and second inputs to resume the prior rate of acceleration comprises increasing the torque applied at least one of the engine and the variator. 
     
     
         16 . A controller for executing a process of range shifting in a split path CVT having a first input driven by an engine and a second input driven by another power source, the CVT also having an output and supporting multiple ratio ranges between the first input and the output, as well as a piston-driven synchronizer actuated via a solenoid valve, the controller having a computer-readable medium containing computer-readable instructions including:
 instructions for receiving an acceleration command to accelerate the split path CVT output;   instructions for causing the split path CVT output to accelerate;   instructions for determining that a shift point has been attained;   instructions for reducing a torque at one or both of the first and second inputs in response to determining that a shift point has been attained;   instructions for activating the solenoid valve and thereby actuating the piston of the synchronizer;   instructions for determining that the range has been shifted;   instructions for increasing the torque applied at one or both of the first and second inputs to resume the prior rate of acceleration.   
     
     
         17 . The controller according to  claim 16 , wherein the instructions for causing the split path CVT output to accelerate further comprise instructions for causing one of the variator and the engine to accelerate. 
     
     
         18 . The controller according to  claim 16 , wherein the instructions for reducing a torque at one or both of the first and second inputs further comprise instructions for reducing a torque at one or both of the engine and variator. 
     
     
         19 . The controller according to  claim 16 , wherein the instructions for determining that the range has been shifted comprise instructions for detecting a position of a range shifting member via a position switch. 
     
     
         20 . The controller according to  claim 16 , wherein the instructions for increasing the torque applied at one or both of the first and second inputs to resume the prior rate of acceleration comprise instructions for increasing the torque applied at least one of the engine and the variator.