Automatic Transmission Pre-Shift Control Delay for Synchronization Stability
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Solution Overview
Problem
Conventional automatic transmissions experience torque fluctuations due to reaction forces from the road, leading to temporary failures in synchronization mechanisms during pre-shift control, which shortens their service life and causes gear noise, affecting marketability.
Innovation Solution
The automatic transmission employs dual power transmission paths with synchronized mechanisms and control means to delay pre-shift control when torque fluctuations are anticipated, ensuring stable connection operations and preventing gear noise by calculating convergence times based on motive power differences and vehicle speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pre-shift control is executed in conventional automatic transmissions, then shift operations can be performed, but synchronization mechanisms suffer from temporary failures due to torque fluctuations, shortening their service life
Solution Approach 1:
The control means determines whether motive power fluctuation will occur before executing pre-shift control. When fluctuation is predicted, the pre-shift control is delayed until the fluctuation subsides. This preliminary assessment prevents synchronization failures by ensuring pre-shift control only executes during stable torque conditions, thereby maintaining reliability while preserving shift operation capability.
2Productivity
If pre-shift control is executed during torque fluctuation, then shift operations proceed, but gear noise occurs due to synchronization failures
Solution Approach 1:
The control means uses the presence of torque fluctuation as a diagnostic criterion to delay pre-shift control. By detecting fluctuation conditions and postponing synchronization operations until stability is achieved, the system eliminates gear noise caused by premature synchronization attempts, while still maintaining efficient shift operations through rapid execution when conditions are favorable.
3Reliability
If pre-shift control is delayed when torque fluctuation is detected, then synchronization stability improves, but shift operation time increases
Solution Approach 1:
The control means performs a preliminary determination of torque fluctuation conditions before initiating pre-shift control. When no fluctuation is detected, pre-shift control executes immediately without delay. This selective timing approach ensures synchronization stability is maintained only when necessary, while minimizing shift operation time by avoiding unnecessary delays during stable conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the stability and reliability of synchronization mechanisms, prolongs their service life, and improves marketability by avoiding synchronization failures and gear noise, while allowing for faster shift operations when conditions permit.
Implementation Method 1
This generates frictional forces between the blocking ring and the transmission gear, to rotate an outer ring of the blocking ring, whereby the spline teeth of the sleeve are brought into contact with ring gear teeth of the blocking ring.
Data Source
AI summary
An automatic transmission capable of improving stability and reliability of connection operation of a synchronization mechanism when pre-shift control is executed, thereby making it possible to prolong the service life of the mechanism and improve marketability thereof. To change the speed position of a vehicle, one of two power transmission paths from an internal combustion engine to drive wheels is switched to the other, and pre-shift control is executed before switching the path. In doing this, when conditions for executing the pre-shift control are satisfied, whether or not a motive power fluctuation state of the engine occurs after satisfaction of the execution conditions is determined. If the motive power fluctuation state occurs, delay control for delaying the start of the pre-shift control is executed, whereas if the same does not occur, the pre-shift control is executed without executing the delay control.