Hybrid Power Train Variable Shift Ratio Torque Control
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Solution Overview
Problem
Conventional hybrid power trains with manual transmissions face challenges in ensuring smooth shift feelings and preventing torque interruptions during gear changes, leading to poor shift quality and fuel efficiency due to wide intervals between shift stages and inherent AMT drawbacks.
Innovation Solution
A hybrid power train configuration featuring a synchromesh type manual transmission with a gear module, a motor-driven second input shaft, a clutch mechanism, and variable shift ratio providing means using an external engaged-gear pair to establish effective shift ratios and prevent torque interruptions by allowing selective transmission in two different shift ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional AMT is used to control the motor and transmission, then the structure is simplified and ease of manufacture is improved, but torque interruptions occur during gear changes and shift quality deteriorates
Solution Approach 1:
The synchronizer is pre-positioned and pre-engaged with the gear before the clutch disengages, so that when the clutch cuts power to the input shaft, the gear is already meshed and ready to transmit torque immediately when power is restored, eliminating torque interruption and shift quality deterioration while maintaining AMT simplicity
2Device complexity
If wide intervals between shift stages are used in an AMT, then the device complexity is reduced, but smooth shift feeling cannot be ensured and shift quality worsens
Solution Approach 1:
The synchronizer mechanism is activated before the actual gear change to pre-align and pre-mesh the gears, ensuring that when the clutch engages/disengages, the transmission can immediately transmit torque through the new gear ratio without interruption, maintaining smooth shift feeling with simpler wide-interval gearing
3Use of energy by moving object
If the hybrid power train is designed with main reduction gears for low speeds and speed-increasing gears for high speeds, then fuel efficiency is improved, but torque interruptions occur at gear changes and shift quality deteriorates
Solution Approach 1:
The synchronizer is engaged in advance to pre-mesh the gears before the clutch cuts power, so that when the clutch re-engages after a gear change, torque is immediately transmitted through the newly engaged gear pair without interruption, eliminating shift quality deterioration while maintaining the fuel-efficient division of labor between reduction and speed-increasing gears
Data Source
AI summary
A hybrid power train for a vehicle may include a gear module having a plurality of shift stages of a synchromesh type on a first input shaft and an output shaft arranged in parallel, a second input shaft driven by a motor and disposed coaxially with the first input shaft, a clutch means for connecting or disconnecting the second input shaft and the first input shaft, and variable shift ratio providing means for transmitting the torque of the second input shaft to the output shaft through an external engaged-gear pair selectively in two different shift ratios.