Split-Axis Transmission Hybrid System for Seamless Torque Transitions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle transmissions suffer from power losses and inefficiencies during gear ratio changes, particularly in automated mechanical transmissions and dual-clutch transmissions, which can lead to reduced performance and drivability due to incorrect gear preselection and torque interruptions.
Innovation Solution
A split-axis transmission hybrid system utilizing two planetary gear sets to provide parallel torque paths, allowing for improved preselection of target gears and minimizing torque interruption during gear changes, with the option to couple a secondary power source to either the input or output axis to enhance efficiency and drivability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If automated mechanical transmissions or dual-clutch transmissions are used to automatically determine gear shifts, then shifting speed and automation are improved, but power losses during shifting and torque interruptions occur
Solution Approach 1:
The transmission system is divided into two independent planetary gear sets (first and second torque paths) that operate in parallel. Each torque path can be independently engaged or disengaged without affecting the other, allowing one path to be preselected while the other transmits torque, thereby eliminating the need to disconnect the power source during shifts and reducing power losses.
Solution Approach 2:
The system preselects a target gear ratio in advance by configuring the desired gear ratio in the opposite torque path before the shift is needed. This allows the transmission to switch between torque paths smoothly without interruption, as the target gear is already prepared and ready to engage immediately when the shift command is executed.
2Device complexity
If dual-clutch transmissions preselect only one gear ratio at a time, then device complexity is reduced, but excessive delays occur when incorrect gear prediction happens
Solution Approach 1:
The transmission is segmented into two independent planetary gear sets, each capable of handling different gear ratios. This segmentation allows the system to preselect multiple gear ratios simultaneously by configuring different ratios in each torque path, eliminating the bottleneck of single-gear preselection and reducing shift delays when incorrect prediction occurs.
Solution Approach 2:
The system changes the parameter of gear ratio configuration by allowing different gear ratios to be set in each torque path independently. This enables flexible preselection of multiple gear ratios based on driving conditions, and the control system can select the optimal torque path during shifts, thereby reducing delays caused by incorrect gear prediction.
3Ease of operation
If traditional transmissions decouple the power source during gear ratio changes, then gear shifting is simplified, but torque interruption and performance reduction occur
Solution Approach 1:
The transmission system is divided into two independent torque paths with separate planetary gear sets. During a gear ratio change, the system disengages one torque path while simultaneously engaging the other, allowing torque to flow continuously through the active path without interruption. This segmentation eliminates the need to decouple the power source entirely, maintaining torque continuity while enabling smooth gear shifts.
Solution Approach 2:
The system maintains continuous torque transmission by ensuring that while one torque path is being disengaged, the other torque path is already configured and ready to take over. The overlap in configuration and engagement ensures that torque flow never stops, providing continuous useful action from the power source to the drive axles throughout the gear ratio change process.
Data Source
AI summary
A split-axis transmission hybrid system may include two planetary gear sets to provide two parallel torque paths from an input axis to an output axis. A secondary power source may be coupled to either the input axis or the output axis to provide torque to the system. Thus, the split-axis transmission hybrid system may provide the ratio preselection capability and the low power losses of a dual-clutch transmission and the ratio-changing control and smoothness of a traditional powershift automatic transmission, while also providing the improved efficiency and enhanced drivability of a hybrid power source arrangement.